Contract 0xe950284c462d8d00cf8e628791e255604f7b2001

Contract Overview

Balance:
0 MATIC
Txn Hash
Method
Block
From
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Value [Txn Fee]
0xadb40de468ad21a758829c0e0b1e96bb658ff5969b34a82aa9c5190a640e020dBurn334120702023-03-22 3:22:15184 days 8 hrs ago0x52fdcd2f20c852eed8e7d072651901a64a489838 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.0000526275 1.500000016
0xa217c0f9b34d81298e2311534416ac4a380d7540289a838be33a4c70bbb2745fSafe Transfer Fr...331932542023-03-16 18:12:16189 days 17 hrs ago0x4a92ed7514f667f9a7d75a796b5b1f368381d343 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.000108570001 1.500000015
0x788c10634184360641779e0d0bf636353d35112864bf56106a5e191ec30523cfSet Approval For...331430452023-03-15 12:34:02190 days 23 hrs ago0x7941221056f87a7e90b2888e7db8d462026fe717 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.0000804 1.500000016
0xd81da4a310652c055893a1576b4af8ea842e4fd3377dc87a1cdefc8fa4b65189Burn331428862023-03-15 12:28:24190 days 23 hrs ago0x7941221056f87a7e90b2888e7db8d462026fe717 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.0000526455 1.500000016
0x15e257973902b48afeb2771245f8402b3d318f2ab615f04e571c63aeaeed0b09Burn328328282023-03-07 21:24:15198 days 14 hrs ago0x053b1fcabaed2fe7cf35ea95f62a66fe815d74cb IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.000057243534 1.630451859
0x5a2ead1324f57187edba20730a4a812f6055713e3507afc838c803e703eb09daSafe Transfer Fr...326648432023-03-03 18:14:22202 days 17 hrs ago0x0b3b455d1c6c3059d35dc5a8a6526a5ffd7c7dc2 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.00016520294 2.281682515
0xe14a486d21b5b9172decafa098c9cfa76515a2f1b75c4668a168d0028ebaca61Set Approval For...326644942023-03-03 18:02:00202 days 18 hrs ago0x0b3b455d1c6c3059d35dc5a8a6526a5ffd7c7dc2 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.000132864747 2.478819912
0x4bb1f5e9cb40b8dd4de7584e44ca2b1f82d94197cbee3d16e115ab2a3ef9a66aBurn326643692023-03-03 17:57:36202 days 18 hrs ago0x0b3b455d1c6c3059d35dc5a8a6526a5ffd7c7dc2 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.000087028888 2.478819912
0x8e1e694d248f3ce66dd040f90f48ba0c0ccf741b6007b540135d98eabcc2923cBurn326228562023-03-02 17:25:43203 days 18 hrs ago0xaf90c638b9ee4e6d7623a73c37860bedc7dd3360 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.000180895757 5.152404168
0x8728629c803db60aa2b7db89765e2f444235ba7db7396f2a90c5adae2162498eSet Approval For...325806832023-03-01 16:32:03204 days 19 hrs ago0xc7ff56702d5acf15cfa88ca581bb8d9a32818a40 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.0000536 1.000000018
0x7201131836ffe1d74954e0f1a08f07fab399d2e6076fb177eae9c316510d5821Set Approval For...325805612023-03-01 16:27:45204 days 19 hrs ago0xc7ff56702d5acf15cfa88ca581bb8d9a32818a40 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.0000536 1.000000018
0x7a4ea431895b63e804fe83e5bec6313fdac7c2c95d629c6ea1f52e0c650389b6Set Approval For...322096682023-02-19 21:56:09214 days 14 hrs ago0xc7ff56702d5acf15cfa88ca581bb8d9a32818a40 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.0000536 1.000000015
0x31dd55f69c8123c35c1bd6bc7830cc9cf4b413da5d023b40bfdc9efe1e6f238dSet Approval For...317824712023-02-06 11:18:43228 days 47 mins ago0xd6ed8b38841f1fc64b2704d0a5ff77c3d1d97874 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.00008041.500000016
0x3113dc94329ce70100897cca224d8367def3c9358a83f09c200025a959f0e854Initialize317824712023-02-06 11:18:43228 days 47 mins ago0xd6ed8b38841f1fc64b2704d0a5ff77c3d1d97874 IN  0xe950284c462d8d00cf8e628791e255604f7b20010 MATIC0.0005314575051.500000016
0xf9a80770ad6de5f94425ad687b1082edb64651e1c9af070af040f8cb7f06069a0x60806040317824712023-02-06 11:18:43228 days 47 mins ago0xd6ed8b38841f1fc64b2704d0a5ff77c3d1d97874 IN  Contract Creation0 MATIC0.0008544585091.500000016
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This contract contains unverified libraries: __CACHE_BREAKER__

Similar Match Source Code
This contract matches the deployed ByteCode of the Source Code for Contract 0x8e586C52315B6D2CbEd7d6bFBd05d15eaDF3759F
The constructor portion of the code might be different and could alter the actual behaviour of the contract

Contract Name:
TransparentUpgradeableProxy

Compiler Version
v0.7.6+commit.7338295f

Optimization Enabled:
Yes with 200 runs

Other Settings:
default evmVersion, MIT license
File 1 of 79 : BaseEnigmaNFT1155.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;

import "@openzeppelin/contracts-upgradeable/token/ERC1155/ERC1155BurnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/utils/EnumerableMapUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/utils/StringsUpgradeable.sol";
import "../interfaces/ITransferGatekeeper.sol";
import "../interfaces/IRoyaltyAwareNFT.sol";

/// @title BaseEnigmaNFT1155
///
/// @dev This contract is a ERC1155 burnable and upgradable based in openZeppelin v3.4.0.
///         Be careful when upgrade, you must respect the same storage.

abstract contract BaseEnigmaNFT1155 is IRoyaltyAwareNFT, ERC1155BurnableUpgradeable, OwnableUpgradeable {
    using EnumerableMapUpgradeable for EnumerableMapUpgradeable.UintToAddressMap;
    using StringsUpgradeable for uint256;

    /* Storage */
    //mapping from token ID to account balances
    mapping(uint256 => address) private creators;
    //mapping for token royaltyFee
    mapping(uint256 => uint256) private _royaltyFee;
    //mapping for token URIs
    mapping(uint256 => string) private _tokenURIs;
    //mapping for token owners
    EnumerableMapUpgradeable.UintToAddressMap private _tokenOwners;

    //tokens base uri
    string public tokenURIPrefix;

    string private _name;

    string private _symbol;

    //token id counter, increase by 1 for each new mint
    uint256 public newItemId;

    //Transfer Gatekeeper with logic to allow token transfers
    ITransferGatekeeper public transferGatekeeper;

    /* events */
    event TokenBaseURI(string value);

    /* functions */

    /**
     * @notice Initialize NFT1155 contract.
     *
     * @param name_ the token name
     * @param symbol_ the token symbol
     * @param tokenURIPrefix_ the toke base uri
     */
    function initialize(
        string memory name_,
        string memory symbol_,
        string memory tokenURIPrefix_
    ) external initializer {
        __ERC1155_init(tokenURIPrefix_);
        __ERC1155Burnable_init();
        __Ownable_init();

        _name = name_;
        _symbol = symbol_;
        newItemId = 1;
        _setTokenURIPrefix(tokenURIPrefix_);
    }

    /// oz-upgrades-unsafe-allow constructor
    // solhint-disable-next-line
    constructor() initializer {}

    function name() external view virtual returns (string memory) {
        return _name;
    }

    function symbol() external view virtual returns (string memory) {
        return _symbol;
    }

    /**
     * @notice Internal function to set the token URI for a given token.
     * Reverts if the token ID does not exist.
     * @param tokenId_ uint256 ID of the token to set its URI
     * @param uri_ string URI to assign
     */
    function _setTokenURI(uint256 tokenId_, string memory uri_) internal {
        _tokenURIs[tokenId_] = uri_;
    }

    /**
     * @notice Get the royalty associated with tokenID.
     * @param tokenId ID of the Token.
     * @return royaltyFee of given ID.
     */
    function royaltyFee(uint256 tokenId) external view virtual override returns (uint256) {
        return _royaltyFee[tokenId];
    }

    /**
     * @notice Get the creator of given tokenID.
     * @param tokenId ID of the Token.
     * @return creator of given ID.
     */
    function getCreator(uint256 tokenId) external view virtual override returns (address) {
        return creators[tokenId];
    }

    /**
     * @dev Internal function to set the token URI for all the tokens.
     * @param _tokenURIPrefix string memory _tokenURIPrefix of the tokens.
     */
    function _setTokenURIPrefix(string memory _tokenURIPrefix) internal {
        tokenURIPrefix = _tokenURIPrefix;
        emit TokenBaseURI(_tokenURIPrefix);
    }

    /**
     * @dev Returns an URI for a given token ID.
     * Throws if the token ID does not exist. May return an empty string.
     * @param tokenId uint256 ID of the token to query
     */
    function tokenURI(uint256 tokenId) public view virtual returns (string memory) {
        require(_exists(tokenId), "ERC1155Metadata: URI query for nonexistent token");
        string memory _tokenURI = _tokenURIs[tokenId];
        string memory base = tokenURIPrefix;

        if (bytes(base).length == 0) {
            return _tokenURI;
        }
        if (bytes(_tokenURI).length > 0) {
            return string(abi.encodePacked(base, _tokenURI));
        }
        return string(abi.encodePacked(base, tokenId.toString()));
    }

    /**
     * @dev Returns the URI for token type `id`.
     *
     * If the `\{id\}` substring is present in the URI, it must be replaced by
     * clients with the actual token type ID.
     */
    function uri(uint256 id) external view override returns (string memory) {
        return tokenURI(id);
    }

    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _tokenOwners.contains(tokenId);
    }

    /**
     * @notice Get the balance of an account's Tokens.
     * @param account The address of the token holder
     * @param tokenId ID of the Token
     * @return The owner's balance of the Token type requested
     */

    function balanceOf(address account, uint256 tokenId) public view override returns (uint256) {
        require(_exists(tokenId), "ERC1155Metadata: balance query for nonexistent token");
        return super.balanceOf(account, tokenId);
    }

    /**
     * @notice call transfer fucntion after check transfer gatekeeper allowance
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        uint256 amount,
        bytes memory data
    ) public virtual override {
        bytes memory allData = abi.encode("1155", tokenId, amount, data);
        require(transferGatekeeper.canTransfer(from, to, _msgSender(), allData), "Transfer not approved");
        super.safeTransferFrom(from, to, tokenId, amount, data);
    }

    /**
     * @notice call transfer fucntion after check transfer gatekeeper allowance
     */
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) public virtual override {
        bytes memory allData = abi.encode("1155_batch", ids, amounts, data);
        require(transferGatekeeper.canTransfer(from, to, _msgSender(), allData), "Batch transfer not approved");
        super.safeBatchTransferFrom(from, to, ids, amounts, data);
    }

    /**
     * @dev Internal function to mint a new token.
     * Reverts if the given token ID already exists.
     * @param tokenId_ uint256 ID of the token to be minted
     * @param supply_ uint256 supply of the token to be minted
     * @param uri_ string memory URI of the token to be minted
     * @param fee_ uint256 royalty of the token to be minted
     */

    function _mint(
        uint256 tokenId_,
        uint256 supply_,
        string memory uri_,
        uint256 fee_
    ) internal {
        require(!_exists(tokenId_), "ERC1155: token already minted");
        require(supply_ != 0, "Supply should be positive");
        require(bytes(uri_).length > 0, "uri should be set");

        creators[tokenId_] = msg.sender;
        require(_tokenOwners.set(tokenId_, msg.sender), "ERC1155: token already minted");
        _royaltyFee[tokenId_] = fee_;
        _setTokenURI(tokenId_, uri_);

        emit URI(uri_, tokenId_);
        super._mint(msg.sender, tokenId_, supply_, "");
    }

    /**
     * @notice call burn function after check that token exists
     */
    function _burn(
        address account,
        uint256 tokenId,
        uint256 amount
    ) internal virtual override {
        require(_exists(tokenId), "ERC1155Metadata: burn query for nonexistent token");
        super._burn(account, tokenId, amount);
    }

    /**
     * @notice burn tokens to msg.sender
     */
    function burn(uint256 tokenId, uint256 amount) external {
        _burn(msg.sender, tokenId, amount);
    }

    /**
     * @dev external function to set the token URI for all the tokens.
     * @param baseURI_ string memory _tokenURIPrefix of the tokens.
     */
    function setBaseURI(string memory baseURI_) external onlyOwner {
        _setTokenURIPrefix(baseURI_);
    }

    /**
     * @notice Set a transferGatekeeper with the logic to allow transfer NFTs
     *
     * @param _transferGatekeeper The Transfer Gatekeeper contract address
     */
    function setTransferGatekeeper(ITransferGatekeeper _transferGatekeeper) external onlyOwner {
        transferGatekeeper = _transferGatekeeper;
    }
}

File 2 of 79 : ERC1155BurnableUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./ERC1155Upgradeable.sol";
import "../../proxy/Initializable.sol";

/**
 * @dev Extension of {ERC1155} that allows token holders to destroy both their
 * own tokens and those that they have been approved to use.
 *
 * _Available since v3.1._
 */
abstract contract ERC1155BurnableUpgradeable is Initializable, ERC1155Upgradeable {
    function __ERC1155Burnable_init() internal initializer {
        __Context_init_unchained();
        __ERC165_init_unchained();
        __ERC1155Burnable_init_unchained();
    }

    function __ERC1155Burnable_init_unchained() internal initializer {
    }
    function burn(address account, uint256 id, uint256 value) public virtual {
        require(
            account == _msgSender() || isApprovedForAll(account, _msgSender()),
            "ERC1155: caller is not owner nor approved"
        );

        _burn(account, id, value);
    }

    function burnBatch(address account, uint256[] memory ids, uint256[] memory values) public virtual {
        require(
            account == _msgSender() || isApprovedForAll(account, _msgSender()),
            "ERC1155: caller is not owner nor approved"
        );

        _burnBatch(account, ids, values);
    }
    uint256[50] private __gap;
}

File 3 of 79 : OwnableUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../utils/ContextUpgradeable.sol";
import "../proxy/Initializable.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    function __Ownable_init() internal initializer {
        __Context_init_unchained();
        __Ownable_init_unchained();
    }

    function __Ownable_init_unchained() internal initializer {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
    uint256[49] private __gap;
}

File 4 of 79 : EnumerableMapUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Library for managing an enumerable variant of Solidity's
 * https://solidity.readthedocs.io/en/latest/types.html#mapping-types[`mapping`]
 * type.
 *
 * Maps have the following properties:
 *
 * - Entries are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Entries are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableMap for EnumerableMap.UintToAddressMap;
 *
 *     // Declare a set state variable
 *     EnumerableMap.UintToAddressMap private myMap;
 * }
 * ```
 *
 * As of v3.0.0, only maps of type `uint256 -> address` (`UintToAddressMap`) are
 * supported.
 */
library EnumerableMapUpgradeable {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Map type with
    // bytes32 keys and values.
    // The Map implementation uses private functions, and user-facing
    // implementations (such as Uint256ToAddressMap) are just wrappers around
    // the underlying Map.
    // This means that we can only create new EnumerableMaps for types that fit
    // in bytes32.

    struct MapEntry {
        bytes32 _key;
        bytes32 _value;
    }

    struct Map {
        // Storage of map keys and values
        MapEntry[] _entries;

        // Position of the entry defined by a key in the `entries` array, plus 1
        // because index 0 means a key is not in the map.
        mapping (bytes32 => uint256) _indexes;
    }

    /**
     * @dev Adds a key-value pair to a map, or updates the value for an existing
     * key. O(1).
     *
     * Returns true if the key was added to the map, that is if it was not
     * already present.
     */
    function _set(Map storage map, bytes32 key, bytes32 value) private returns (bool) {
        // We read and store the key's index to prevent multiple reads from the same storage slot
        uint256 keyIndex = map._indexes[key];

        if (keyIndex == 0) { // Equivalent to !contains(map, key)
            map._entries.push(MapEntry({ _key: key, _value: value }));
            // The entry is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            map._indexes[key] = map._entries.length;
            return true;
        } else {
            map._entries[keyIndex - 1]._value = value;
            return false;
        }
    }

    /**
     * @dev Removes a key-value pair from a map. O(1).
     *
     * Returns true if the key was removed from the map, that is if it was present.
     */
    function _remove(Map storage map, bytes32 key) private returns (bool) {
        // We read and store the key's index to prevent multiple reads from the same storage slot
        uint256 keyIndex = map._indexes[key];

        if (keyIndex != 0) { // Equivalent to contains(map, key)
            // To delete a key-value pair from the _entries array in O(1), we swap the entry to delete with the last one
            // in the array, and then remove the last entry (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = keyIndex - 1;
            uint256 lastIndex = map._entries.length - 1;

            // When the entry to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

            MapEntry storage lastEntry = map._entries[lastIndex];

            // Move the last entry to the index where the entry to delete is
            map._entries[toDeleteIndex] = lastEntry;
            // Update the index for the moved entry
            map._indexes[lastEntry._key] = toDeleteIndex + 1; // All indexes are 1-based

            // Delete the slot where the moved entry was stored
            map._entries.pop();

            // Delete the index for the deleted slot
            delete map._indexes[key];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the key is in the map. O(1).
     */
    function _contains(Map storage map, bytes32 key) private view returns (bool) {
        return map._indexes[key] != 0;
    }

    /**
     * @dev Returns the number of key-value pairs in the map. O(1).
     */
    function _length(Map storage map) private view returns (uint256) {
        return map._entries.length;
    }

   /**
    * @dev Returns the key-value pair stored at position `index` in the map. O(1).
    *
    * Note that there are no guarantees on the ordering of entries inside the
    * array, and it may change when more entries are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Map storage map, uint256 index) private view returns (bytes32, bytes32) {
        require(map._entries.length > index, "EnumerableMap: index out of bounds");

        MapEntry storage entry = map._entries[index];
        return (entry._key, entry._value);
    }

    /**
     * @dev Tries to returns the value associated with `key`.  O(1).
     * Does not revert if `key` is not in the map.
     */
    function _tryGet(Map storage map, bytes32 key) private view returns (bool, bytes32) {
        uint256 keyIndex = map._indexes[key];
        if (keyIndex == 0) return (false, 0); // Equivalent to contains(map, key)
        return (true, map._entries[keyIndex - 1]._value); // All indexes are 1-based
    }

    /**
     * @dev Returns the value associated with `key`.  O(1).
     *
     * Requirements:
     *
     * - `key` must be in the map.
     */
    function _get(Map storage map, bytes32 key) private view returns (bytes32) {
        uint256 keyIndex = map._indexes[key];
        require(keyIndex != 0, "EnumerableMap: nonexistent key"); // Equivalent to contains(map, key)
        return map._entries[keyIndex - 1]._value; // All indexes are 1-based
    }

    /**
     * @dev Same as {_get}, with a custom error message when `key` is not in the map.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {_tryGet}.
     */
    function _get(Map storage map, bytes32 key, string memory errorMessage) private view returns (bytes32) {
        uint256 keyIndex = map._indexes[key];
        require(keyIndex != 0, errorMessage); // Equivalent to contains(map, key)
        return map._entries[keyIndex - 1]._value; // All indexes are 1-based
    }

    // UintToAddressMap

    struct UintToAddressMap {
        Map _inner;
    }

    /**
     * @dev Adds a key-value pair to a map, or updates the value for an existing
     * key. O(1).
     *
     * Returns true if the key was added to the map, that is if it was not
     * already present.
     */
    function set(UintToAddressMap storage map, uint256 key, address value) internal returns (bool) {
        return _set(map._inner, bytes32(key), bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the key was removed from the map, that is if it was present.
     */
    function remove(UintToAddressMap storage map, uint256 key) internal returns (bool) {
        return _remove(map._inner, bytes32(key));
    }

    /**
     * @dev Returns true if the key is in the map. O(1).
     */
    function contains(UintToAddressMap storage map, uint256 key) internal view returns (bool) {
        return _contains(map._inner, bytes32(key));
    }

    /**
     * @dev Returns the number of elements in the map. O(1).
     */
    function length(UintToAddressMap storage map) internal view returns (uint256) {
        return _length(map._inner);
    }

   /**
    * @dev Returns the element stored at position `index` in the set. O(1).
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintToAddressMap storage map, uint256 index) internal view returns (uint256, address) {
        (bytes32 key, bytes32 value) = _at(map._inner, index);
        return (uint256(key), address(uint160(uint256(value))));
    }

    /**
     * @dev Tries to returns the value associated with `key`.  O(1).
     * Does not revert if `key` is not in the map.
     *
     * _Available since v3.4._
     */
    function tryGet(UintToAddressMap storage map, uint256 key) internal view returns (bool, address) {
        (bool success, bytes32 value) = _tryGet(map._inner, bytes32(key));
        return (success, address(uint160(uint256(value))));
    }

    /**
     * @dev Returns the value associated with `key`.  O(1).
     *
     * Requirements:
     *
     * - `key` must be in the map.
     */
    function get(UintToAddressMap storage map, uint256 key) internal view returns (address) {
        return address(uint160(uint256(_get(map._inner, bytes32(key)))));
    }

    /**
     * @dev Same as {get}, with a custom error message when `key` is not in the map.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryGet}.
     */
    function get(UintToAddressMap storage map, uint256 key, string memory errorMessage) internal view returns (address) {
        return address(uint160(uint256(_get(map._inner, bytes32(key), errorMessage))));
    }
}

File 5 of 79 : StringsUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev String operations.
 */
library StringsUpgradeable {
    /**
     * @dev Converts a `uint256` to its ASCII `string` representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        uint256 index = digits - 1;
        temp = value;
        while (temp != 0) {
            buffer[index--] = bytes1(uint8(48 + temp % 10));
            temp /= 10;
        }
        return string(buffer);
    }
}

File 6 of 79 : ITransferGatekeeper.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

/// @title ITransferGatekeeper
/// @notice an interface that allows an asset transfer to be guard.

interface ITransferGatekeeper {
    /**
     * @param _from the address that owns what's being transfered
     * @param _to the address that would receive what's being transfered
     * @param _proxy the address that wants to transfer
     * @param _data any other aditional data that might be relevant to allow/block the transfer
     * @dev Returns true if this transfer is allowed under current context
     */
    function canTransfer(
        address _from,
        address _to,
        address _proxy,
        bytes memory _data
    ) external view returns (bool);
}

File 7 of 79 : IRoyaltyAwareNFT.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

interface IRoyaltyAwareNFT {
    function royaltyFee(uint256 tokenId) external view returns (uint256);

    function getCreator(uint256 tokenId) external view returns (address);
}

File 8 of 79 : ERC1155Upgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./IERC1155Upgradeable.sol";
import "./IERC1155MetadataURIUpgradeable.sol";
import "./IERC1155ReceiverUpgradeable.sol";
import "../../utils/ContextUpgradeable.sol";
import "../../introspection/ERC165Upgradeable.sol";
import "../../math/SafeMathUpgradeable.sol";
import "../../utils/AddressUpgradeable.sol";
import "../../proxy/Initializable.sol";

/**
 *
 * @dev Implementation of the basic standard multi-token.
 * See https://eips.ethereum.org/EIPS/eip-1155
 * Originally based on code by Enjin: https://github.com/enjin/erc-1155
 *
 * _Available since v3.1._
 */
contract ERC1155Upgradeable is Initializable, ContextUpgradeable, ERC165Upgradeable, IERC1155Upgradeable, IERC1155MetadataURIUpgradeable {
    using SafeMathUpgradeable for uint256;
    using AddressUpgradeable for address;

    // Mapping from token ID to account balances
    mapping (uint256 => mapping(address => uint256)) private _balances;

    // Mapping from account to operator approvals
    mapping (address => mapping(address => bool)) private _operatorApprovals;

    // Used as the URI for all token types by relying on ID substitution, e.g. https://token-cdn-domain/{id}.json
    string private _uri;

    /*
     *     bytes4(keccak256('balanceOf(address,uint256)')) == 0x00fdd58e
     *     bytes4(keccak256('balanceOfBatch(address[],uint256[])')) == 0x4e1273f4
     *     bytes4(keccak256('setApprovalForAll(address,bool)')) == 0xa22cb465
     *     bytes4(keccak256('isApprovedForAll(address,address)')) == 0xe985e9c5
     *     bytes4(keccak256('safeTransferFrom(address,address,uint256,uint256,bytes)')) == 0xf242432a
     *     bytes4(keccak256('safeBatchTransferFrom(address,address,uint256[],uint256[],bytes)')) == 0x2eb2c2d6
     *
     *     => 0x00fdd58e ^ 0x4e1273f4 ^ 0xa22cb465 ^
     *        0xe985e9c5 ^ 0xf242432a ^ 0x2eb2c2d6 == 0xd9b67a26
     */
    bytes4 private constant _INTERFACE_ID_ERC1155 = 0xd9b67a26;

    /*
     *     bytes4(keccak256('uri(uint256)')) == 0x0e89341c
     */
    bytes4 private constant _INTERFACE_ID_ERC1155_METADATA_URI = 0x0e89341c;

    /**
     * @dev See {_setURI}.
     */
    function __ERC1155_init(string memory uri_) internal initializer {
        __Context_init_unchained();
        __ERC165_init_unchained();
        __ERC1155_init_unchained(uri_);
    }

    function __ERC1155_init_unchained(string memory uri_) internal initializer {
        _setURI(uri_);

        // register the supported interfaces to conform to ERC1155 via ERC165
        _registerInterface(_INTERFACE_ID_ERC1155);

        // register the supported interfaces to conform to ERC1155MetadataURI via ERC165
        _registerInterface(_INTERFACE_ID_ERC1155_METADATA_URI);
    }

    /**
     * @dev See {IERC1155MetadataURI-uri}.
     *
     * This implementation returns the same URI for *all* token types. It relies
     * on the token type ID substitution mechanism
     * https://eips.ethereum.org/EIPS/eip-1155#metadata[defined in the EIP].
     *
     * Clients calling this function must replace the `\{id\}` substring with the
     * actual token type ID.
     */
    function uri(uint256) external view virtual override returns (string memory) {
        return _uri;
    }

    /**
     * @dev See {IERC1155-balanceOf}.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function balanceOf(address account, uint256 id) public view virtual override returns (uint256) {
        require(account != address(0), "ERC1155: balance query for the zero address");
        return _balances[id][account];
    }

    /**
     * @dev See {IERC1155-balanceOfBatch}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(
        address[] memory accounts,
        uint256[] memory ids
    )
        public
        view
        virtual
        override
        returns (uint256[] memory)
    {
        require(accounts.length == ids.length, "ERC1155: accounts and ids length mismatch");

        uint256[] memory batchBalances = new uint256[](accounts.length);

        for (uint256 i = 0; i < accounts.length; ++i) {
            batchBalances[i] = balanceOf(accounts[i], ids[i]);
        }

        return batchBalances;
    }

    /**
     * @dev See {IERC1155-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        require(_msgSender() != operator, "ERC1155: setting approval status for self");

        _operatorApprovals[_msgSender()][operator] = approved;
        emit ApprovalForAll(_msgSender(), operator, approved);
    }

    /**
     * @dev See {IERC1155-isApprovedForAll}.
     */
    function isApprovedForAll(address account, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[account][operator];
    }

    /**
     * @dev See {IERC1155-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes memory data
    )
        public
        virtual
        override
    {
        require(to != address(0), "ERC1155: transfer to the zero address");
        require(
            from == _msgSender() || isApprovedForAll(from, _msgSender()),
            "ERC1155: caller is not owner nor approved"
        );

        address operator = _msgSender();

        _beforeTokenTransfer(operator, from, to, _asSingletonArray(id), _asSingletonArray(amount), data);

        _balances[id][from] = _balances[id][from].sub(amount, "ERC1155: insufficient balance for transfer");
        _balances[id][to] = _balances[id][to].add(amount);

        emit TransferSingle(operator, from, to, id, amount);

        _doSafeTransferAcceptanceCheck(operator, from, to, id, amount, data);
    }

    /**
     * @dev See {IERC1155-safeBatchTransferFrom}.
     */
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    )
        public
        virtual
        override
    {
        require(ids.length == amounts.length, "ERC1155: ids and amounts length mismatch");
        require(to != address(0), "ERC1155: transfer to the zero address");
        require(
            from == _msgSender() || isApprovedForAll(from, _msgSender()),
            "ERC1155: transfer caller is not owner nor approved"
        );

        address operator = _msgSender();

        _beforeTokenTransfer(operator, from, to, ids, amounts, data);

        for (uint256 i = 0; i < ids.length; ++i) {
            uint256 id = ids[i];
            uint256 amount = amounts[i];

            _balances[id][from] = _balances[id][from].sub(
                amount,
                "ERC1155: insufficient balance for transfer"
            );
            _balances[id][to] = _balances[id][to].add(amount);
        }

        emit TransferBatch(operator, from, to, ids, amounts);

        _doSafeBatchTransferAcceptanceCheck(operator, from, to, ids, amounts, data);
    }

    /**
     * @dev Sets a new URI for all token types, by relying on the token type ID
     * substitution mechanism
     * https://eips.ethereum.org/EIPS/eip-1155#metadata[defined in the EIP].
     *
     * By this mechanism, any occurrence of the `\{id\}` substring in either the
     * URI or any of the amounts in the JSON file at said URI will be replaced by
     * clients with the token type ID.
     *
     * For example, the `https://token-cdn-domain/\{id\}.json` URI would be
     * interpreted by clients as
     * `https://token-cdn-domain/000000000000000000000000000000000000000000000000000000000004cce0.json`
     * for token type ID 0x4cce0.
     *
     * See {uri}.
     *
     * Because these URIs cannot be meaningfully represented by the {URI} event,
     * this function emits no events.
     */
    function _setURI(string memory newuri) internal virtual {
        _uri = newuri;
    }

    /**
     * @dev Creates `amount` tokens of token type `id`, and assigns them to `account`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - If `account` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function _mint(address account, uint256 id, uint256 amount, bytes memory data) internal virtual {
        require(account != address(0), "ERC1155: mint to the zero address");

        address operator = _msgSender();

        _beforeTokenTransfer(operator, address(0), account, _asSingletonArray(id), _asSingletonArray(amount), data);

        _balances[id][account] = _balances[id][account].add(amount);
        emit TransferSingle(operator, address(0), account, id, amount);

        _doSafeTransferAcceptanceCheck(operator, address(0), account, id, amount, data);
    }

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {_mint}.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function _mintBatch(address to, uint256[] memory ids, uint256[] memory amounts, bytes memory data) internal virtual {
        require(to != address(0), "ERC1155: mint to the zero address");
        require(ids.length == amounts.length, "ERC1155: ids and amounts length mismatch");

        address operator = _msgSender();

        _beforeTokenTransfer(operator, address(0), to, ids, amounts, data);

        for (uint i = 0; i < ids.length; i++) {
            _balances[ids[i]][to] = amounts[i].add(_balances[ids[i]][to]);
        }

        emit TransferBatch(operator, address(0), to, ids, amounts);

        _doSafeBatchTransferAcceptanceCheck(operator, address(0), to, ids, amounts, data);
    }

    /**
     * @dev Destroys `amount` tokens of token type `id` from `account`
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens of token type `id`.
     */
    function _burn(address account, uint256 id, uint256 amount) internal virtual {
        require(account != address(0), "ERC1155: burn from the zero address");

        address operator = _msgSender();

        _beforeTokenTransfer(operator, account, address(0), _asSingletonArray(id), _asSingletonArray(amount), "");

        _balances[id][account] = _balances[id][account].sub(
            amount,
            "ERC1155: burn amount exceeds balance"
        );

        emit TransferSingle(operator, account, address(0), id, amount);
    }

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {_burn}.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     */
    function _burnBatch(address account, uint256[] memory ids, uint256[] memory amounts) internal virtual {
        require(account != address(0), "ERC1155: burn from the zero address");
        require(ids.length == amounts.length, "ERC1155: ids and amounts length mismatch");

        address operator = _msgSender();

        _beforeTokenTransfer(operator, account, address(0), ids, amounts, "");

        for (uint i = 0; i < ids.length; i++) {
            _balances[ids[i]][account] = _balances[ids[i]][account].sub(
                amounts[i],
                "ERC1155: burn amount exceeds balance"
            );
        }

        emit TransferBatch(operator, account, address(0), ids, amounts);
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning, as well as batched variants.
     *
     * The same hook is called on both single and batched variants. For single
     * transfers, the length of the `id` and `amount` arrays will be 1.
     *
     * Calling conditions (for each `id` and `amount` pair):
     *
     * - When `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * of token type `id` will be  transferred to `to`.
     * - When `from` is zero, `amount` tokens of token type `id` will be minted
     * for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens of token type `id`
     * will be burned.
     * - `from` and `to` are never both zero.
     * - `ids` and `amounts` have the same, non-zero length.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address operator,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    )
        internal
        virtual
    { }

    function _doSafeTransferAcceptanceCheck(
        address operator,
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes memory data
    )
        private
    {
        if (to.isContract()) {
            try IERC1155ReceiverUpgradeable(to).onERC1155Received(operator, from, id, amount, data) returns (bytes4 response) {
                if (response != IERC1155ReceiverUpgradeable(to).onERC1155Received.selector) {
                    revert("ERC1155: ERC1155Receiver rejected tokens");
                }
            } catch Error(string memory reason) {
                revert(reason);
            } catch {
                revert("ERC1155: transfer to non ERC1155Receiver implementer");
            }
        }
    }

    function _doSafeBatchTransferAcceptanceCheck(
        address operator,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    )
        private
    {
        if (to.isContract()) {
            try IERC1155ReceiverUpgradeable(to).onERC1155BatchReceived(operator, from, ids, amounts, data) returns (bytes4 response) {
                if (response != IERC1155ReceiverUpgradeable(to).onERC1155BatchReceived.selector) {
                    revert("ERC1155: ERC1155Receiver rejected tokens");
                }
            } catch Error(string memory reason) {
                revert(reason);
            } catch {
                revert("ERC1155: transfer to non ERC1155Receiver implementer");
            }
        }
    }

    function _asSingletonArray(uint256 element) private pure returns (uint256[] memory) {
        uint256[] memory array = new uint256[](1);
        array[0] = element;

        return array;
    }
    uint256[47] private __gap;
}

File 9 of 79 : Initializable.sol
// SPDX-License-Identifier: MIT

// solhint-disable-next-line compiler-version
pragma solidity >=0.4.24 <0.8.0;

import "../utils/AddressUpgradeable.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {UpgradeableProxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 */
abstract contract Initializable {

    /**
     * @dev Indicates that the contract has been initialized.
     */
    bool private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Modifier to protect an initializer function from being invoked twice.
     */
    modifier initializer() {
        require(_initializing || _isConstructor() || !_initialized, "Initializable: contract is already initialized");

        bool isTopLevelCall = !_initializing;
        if (isTopLevelCall) {
            _initializing = true;
            _initialized = true;
        }

        _;

        if (isTopLevelCall) {
            _initializing = false;
        }
    }

    /// @dev Returns true if and only if the function is running in the constructor
    function _isConstructor() private view returns (bool) {
        return !AddressUpgradeable.isContract(address(this));
    }
}

File 10 of 79 : IERC1155Upgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

import "../../introspection/IERC165Upgradeable.sol";

/**
 * @dev Required interface of an ERC1155 compliant contract, as defined in the
 * https://eips.ethereum.org/EIPS/eip-1155[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155Upgradeable is IERC165Upgradeable {
    /**
     * @dev Emitted when `value` tokens of token type `id` are transferred from `from` to `to` by `operator`.
     */
    event TransferSingle(address indexed operator, address indexed from, address indexed to, uint256 id, uint256 value);

    /**
     * @dev Equivalent to multiple {TransferSingle} events, where `operator`, `from` and `to` are the same for all
     * transfers.
     */
    event TransferBatch(address indexed operator, address indexed from, address indexed to, uint256[] ids, uint256[] values);

    /**
     * @dev Emitted when `account` grants or revokes permission to `operator` to transfer their tokens, according to
     * `approved`.
     */
    event ApprovalForAll(address indexed account, address indexed operator, bool approved);

    /**
     * @dev Emitted when the URI for token type `id` changes to `value`, if it is a non-programmatic URI.
     *
     * If an {URI} event was emitted for `id`, the standard
     * https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[guarantees] that `value` will equal the value
     * returned by {IERC1155MetadataURI-uri}.
     */
    event URI(string value, uint256 indexed id);

    /**
     * @dev Returns the amount of tokens of token type `id` owned by `account`.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function balanceOf(address account, uint256 id) external view returns (uint256);

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {balanceOf}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(address[] calldata accounts, uint256[] calldata ids) external view returns (uint256[] memory);

    /**
     * @dev Grants or revokes permission to `operator` to transfer the caller's tokens, according to `approved`,
     *
     * Emits an {ApprovalForAll} event.
     *
     * Requirements:
     *
     * - `operator` cannot be the caller.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns true if `operator` is approved to transfer ``account``'s tokens.
     *
     * See {setApprovalForAll}.
     */
    function isApprovedForAll(address account, address operator) external view returns (bool);

    /**
     * @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If the caller is not `from`, it must be have been approved to spend ``from``'s tokens via {setApprovalForAll}.
     * - `from` must have a balance of tokens of type `id` of at least `amount`.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function safeTransferFrom(address from, address to, uint256 id, uint256 amount, bytes calldata data) external;

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {safeTransferFrom}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function safeBatchTransferFrom(address from, address to, uint256[] calldata ids, uint256[] calldata amounts, bytes calldata data) external;
}

File 11 of 79 : IERC1155MetadataURIUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

import "./IERC1155Upgradeable.sol";

/**
 * @dev Interface of the optional ERC1155MetadataExtension interface, as defined
 * in the https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155MetadataURIUpgradeable is IERC1155Upgradeable {
    /**
     * @dev Returns the URI for token type `id`.
     *
     * If the `\{id\}` substring is present in the URI, it must be replaced by
     * clients with the actual token type ID.
     */
    function uri(uint256 id) external view returns (string memory);
}

File 12 of 79 : IERC1155ReceiverUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../../introspection/IERC165Upgradeable.sol";

/**
 * _Available since v3.1._
 */
interface IERC1155ReceiverUpgradeable is IERC165Upgradeable {

    /**
        @dev Handles the receipt of a single ERC1155 token type. This function is
        called at the end of a `safeTransferFrom` after the balance has been updated.
        To accept the transfer, this must return
        `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))`
        (i.e. 0xf23a6e61, or its own function selector).
        @param operator The address which initiated the transfer (i.e. msg.sender)
        @param from The address which previously owned the token
        @param id The ID of the token being transferred
        @param value The amount of tokens being transferred
        @param data Additional data with no specified format
        @return `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))` if transfer is allowed
    */
    function onERC1155Received(
        address operator,
        address from,
        uint256 id,
        uint256 value,
        bytes calldata data
    )
        external
        returns(bytes4);

    /**
        @dev Handles the receipt of a multiple ERC1155 token types. This function
        is called at the end of a `safeBatchTransferFrom` after the balances have
        been updated. To accept the transfer(s), this must return
        `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))`
        (i.e. 0xbc197c81, or its own function selector).
        @param operator The address which initiated the batch transfer (i.e. msg.sender)
        @param from The address which previously owned the token
        @param ids An array containing ids of each token being transferred (order and length must match values array)
        @param values An array containing amounts of each token being transferred (order and length must match ids array)
        @param data Additional data with no specified format
        @return `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))` if transfer is allowed
    */
    function onERC1155BatchReceived(
        address operator,
        address from,
        uint256[] calldata ids,
        uint256[] calldata values,
        bytes calldata data
    )
        external
        returns(bytes4);
}

File 13 of 79 : ContextUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;
import "../proxy/Initializable.sol";

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract ContextUpgradeable is Initializable {
    function __Context_init() internal initializer {
        __Context_init_unchained();
    }

    function __Context_init_unchained() internal initializer {
    }
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
    uint256[50] private __gap;
}

File 14 of 79 : ERC165Upgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./IERC165Upgradeable.sol";
import "../proxy/Initializable.sol";

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts may inherit from this and call {_registerInterface} to declare
 * their support of an interface.
 */
abstract contract ERC165Upgradeable is Initializable, IERC165Upgradeable {
    /*
     * bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7
     */
    bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;

    /**
     * @dev Mapping of interface ids to whether or not it's supported.
     */
    mapping(bytes4 => bool) private _supportedInterfaces;

    function __ERC165_init() internal initializer {
        __ERC165_init_unchained();
    }

    function __ERC165_init_unchained() internal initializer {
        // Derived contracts need only register support for their own interfaces,
        // we register support for ERC165 itself here
        _registerInterface(_INTERFACE_ID_ERC165);
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     *
     * Time complexity O(1), guaranteed to always use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return _supportedInterfaces[interfaceId];
    }

    /**
     * @dev Registers the contract as an implementer of the interface defined by
     * `interfaceId`. Support of the actual ERC165 interface is automatic and
     * registering its interface id is not required.
     *
     * See {IERC165-supportsInterface}.
     *
     * Requirements:
     *
     * - `interfaceId` cannot be the ERC165 invalid interface (`0xffffffff`).
     */
    function _registerInterface(bytes4 interfaceId) internal virtual {
        require(interfaceId != 0xffffffff, "ERC165: invalid interface id");
        _supportedInterfaces[interfaceId] = true;
    }
    uint256[49] private __gap;
}

File 15 of 79 : SafeMathUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMathUpgradeable {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        uint256 c = a + b;
        if (c < a) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b > a) return (false, 0);
        return (true, a - b);
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) return (true, 0);
        uint256 c = a * b;
        if (c / a != b) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a / b);
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a % b);
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) return 0;
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: division by zero");
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: modulo by zero");
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        return a - b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryDiv}.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a % b;
    }
}

File 16 of 79 : AddressUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library AddressUpgradeable {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

File 17 of 79 : IERC165Upgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165Upgradeable {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

File 18 of 79 : TestEnigmaNFT1155.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "../ERC1155/BaseEnigmaNFT1155.sol";

/// @title TestEnigmaNFT1155
///
/// @dev This contract extends from BaseEnigmaNFT1155 for upgradeablity testing

contract TestEnigmaNFT1155 is BaseEnigmaNFT1155 {
    event CollectibleCreated(uint256 tokenId);

    /**
     * @notice public function to mint a new token.
     * @param uri_ string memory URI of the token to be minted.
     * @param supply_ tokens amount to be minted
     * @param fee_ uint256 royalty of the token to be minted.
     */
    function mint(
        string memory uri_,
        uint256 supply_,
        uint256 fee_
    ) external {
        uint256 tokenCounter = newItemId;
        newItemId = newItemId + 1;
        emit CollectibleCreated(tokenCounter);
        _mint(tokenCounter, supply_, uri_, fee_);
    }
}

File 19 of 79 : EnigmaUserToken1155.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "./BaseEnigmaNFT1155.sol";

/// @title EnigmaUserToken1155
///
/// @dev This contract extends from BaseEnigmaNFT1155

contract EnigmaUserToken1155 is BaseEnigmaNFT1155 {
    /// oz-upgrades-unsafe-allow constructor
    // solhint-disable-next-line
    constructor() initializer {}

    /**
     * @notice public function to mint a new token.
     * @param uri_ string memory URI of the token to be minted.
     * @param supply_ tokens amount to be minted
     * @param fee_ uint256 royalty of the token to be minted.
     */
    function mint(
        string memory uri_,
        uint256 supply_,
        uint256 fee_
    ) external {
        uint256 tokenCounter = newItemId;
        newItemId = newItemId + 1;
        _mint(tokenCounter, supply_, uri_, fee_);
    }
}

File 20 of 79 : EnigmaNFT1155.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "./BaseEnigmaNFT1155.sol";

/// @title EnigmaNFT1155
///
/// @dev This contract extends from BaseEnigmaNFT1155

contract EnigmaNFT1155 is BaseEnigmaNFT1155 {
    struct Sign {
        uint8 v;
        bytes32 r;
        bytes32 s;
    }

    /// oz-upgrades-unsafe-allow constructor
    // solhint-disable-next-line
    constructor() initializer {}

    /**
     * @notice Internal function to verify a sign to mint tokens
     * Reverts if the sign verification fails.
     * @param tokenURI_ string memory URI of the token to be minted.
     * @param sign_ struct combination of uint8, bytes32, bytes32 are v, r, s.
     */
    function verifySign(string memory tokenURI_, Sign memory sign_) internal view {
        bytes32 hash = keccak256(abi.encodePacked(this, tokenURI_));
        require(
            owner() ==
                ecrecover(
                    keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash)),
                    sign_.v,
                    sign_.r,
                    sign_.s
                ),
            "Owner sign verification failed"
        );
    }

    /**
     * @notice public function to mint a new token.
     * @param uri_ string memory URI of the token to be minted.
     * @param supply_ tokens amount to be minted
     * @param fee_ uint256 royalty of the token to be minted.
     * @param sign_ struct combination of uint8, bytes32, bytes32 are v, r, s.
     */
    function mint(
        string memory uri_,
        uint256 supply_,
        uint256 fee_,
        Sign memory sign_
    ) external {
        uint256 tokenCounter = newItemId;
        verifySign(uri_, sign_);
        newItemId = newItemId + 1;
        _mint(tokenCounter, supply_, uri_, fee_);
    }
}

File 21 of 79 : TradeV4.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/math/SafeMathUpgradeable.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts-upgradeable/utils/ReentrancyGuardUpgradeable.sol";
import "../interfaces/ITransferProxy.sol";
import "../interfaces/IRoyaltyAwareNFT.sol";

/// @title TradeV4
///
/// @dev This contract is a Transparent Upgradable based in openZeppelin v3.4.0.
///         Be careful when upgrade, you must respect the same storage.

abstract contract TradeV4 is ReentrancyGuardUpgradeable, OwnableUpgradeable {
    using SafeMathUpgradeable for uint256;

    enum AssetType { ERC1155, ERC721 }

    event SellerFee(uint8 sellerFee);
    event BuyerFee(uint8 buyerFee);
    event CustodialAddressChanged(address prevAddress, address newAddress);
    event BuyAsset(address indexed assetOwner, uint256 indexed tokenId, uint256 quantity, address indexed buyer);
    event ExecuteBid(address indexed assetOwner, uint256 indexed tokenId, uint256 quantity, address indexed buyer);
    event TokenWithdraw(address indexed assetOwner, uint256 indexed authId, uint256 indexed tokenId, uint256 quantity);

    uint8 internal buyerFeePermille;
    uint8 internal sellerFeePermille;
    ITransferProxy public transferProxy;
    address public enigmaNFT721Address;
    address public enigmaNFT1155Address;
    // Address that acts as custodial for platform hold NFTs,
    address public custodialAddress;

    // This is a packed array of booleans, to track processed authorizations
    mapping(uint256 => uint256) internal processedAuthorizationsBitMap;

    struct Fee {
        uint256 platformFee;
        uint256 assetFee;
        uint256 royaltyFee;
        uint256 price;
        address tokenCreator;
    }

    /* An ECDSA signature. */
    struct Sign {
        uint8 v;
        bytes32 r;
        bytes32 s;
    }

    struct Order {
        address seller;
        address buyer;
        address erc20Address;
        address nftAddress;
        AssetType nftType;
        uint256 unitPrice;
        uint256 amount;
        uint256 tokenId;
        uint256 qty;
    }

    struct WithdrawRequest {
        uint256 authId; // Unique id for this withdraw authorization
        address assetAddress;
        AssetType assetType;
        uint256 tokenId;
        uint256 qty;
    }

    function initializeTradeV4(
        uint8 _buyerFee,
        uint8 _sellerFee,
        ITransferProxy _transferProxy,
        address _enigmaNFT721Address,
        address _enigmaNFT1155Address,
        address _custodialAddress
    ) internal initializer {
        buyerFeePermille = _buyerFee;
        sellerFeePermille = _sellerFee;
        transferProxy = _transferProxy;
        enigmaNFT721Address = _enigmaNFT721Address;
        enigmaNFT1155Address = _enigmaNFT1155Address;
        custodialAddress = _custodialAddress;
        __Ownable_init();
        __ReentrancyGuard_init();
    }

    function buyerServiceFee() external view virtual returns (uint8) {
        return buyerFeePermille;
    }

    function sellerServiceFee() external view virtual returns (uint8) {
        return sellerFeePermille;
    }

    function setBuyerServiceFee(uint8 _buyerFee) external onlyOwner returns (bool) {
        buyerFeePermille = _buyerFee;
        emit BuyerFee(buyerFeePermille);
        return true;
    }

    function setSellerServiceFee(uint8 _sellerFee) external onlyOwner returns (bool) {
        sellerFeePermille = _sellerFee;
        emit SellerFee(sellerFeePermille);
        return true;
    }

    function setCustodialAddress(address _custodialAddress) external onlyOwner returns (bool) {
        emit CustodialAddressChanged(custodialAddress, _custodialAddress);
        custodialAddress = _custodialAddress;
        return true;
    }

    function getSigner(bytes32 hash, Sign memory sign) internal pure returns (address) {
        return ecrecover(keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash)), sign.v, sign.r, sign.s);
    }

    function verifySellerSignature(
        address seller,
        uint256 tokenId,
        uint256 amount,
        address paymentAssetAddress,
        address assetAddress,
        Sign memory sign
    ) internal pure {
        bytes32 hash = keccak256(abi.encodePacked(assetAddress, tokenId, paymentAssetAddress, amount));
        require(seller == getSigner(hash, sign), "seller sign verification failed");
    }

    function verifyBuyerSignature(
        address buyer,
        uint256 tokenId,
        uint256 amount,
        address paymentAssetAddress,
        address assetAddress,
        uint256 qty,
        Sign memory sign
    ) internal pure {
        bytes32 hash = keccak256(abi.encodePacked(assetAddress, tokenId, paymentAssetAddress, amount, qty));
        require(buyer == getSigner(hash, sign), "buyer sign verification failed");
    }

    /**
     * @notice Verifies the custodial authorization for this withdraw for this assetOwner
     * @param assetCustodial current asset holder
     * @param assetOwner real asset owner address
     * @param wr struct with the withdraw information. What asset and how much of it
     * @param sign struct combination of uint8, bytes32, bytes32 are v, r, s.
     */
    function verifyWithdrawSignature(
        address assetCustodial,
        address assetOwner,
        WithdrawRequest memory wr,
        Sign memory sign
    ) internal pure {
        bytes32 hash = keccak256(abi.encodePacked(assetOwner, wr.authId, wr.tokenId, wr.assetAddress, wr.qty));
        require(assetCustodial == getSigner(hash, sign), "withdraw sign verification failed");
    }

    function getFees(
        uint256 paymentAmt,
        address buyingAssetAddress,
        uint256 tokenId
    ) internal view returns (Fee memory) {
        address tokenCreator;
        uint256 platformFee;
        uint256 royaltyFee;
        uint256 assetFee;
        uint256 royaltyPermille;
        uint256 price;
        uint256 sellerFee = paymentAmt.mul(sellerFeePermille).div((1000 + buyerFeePermille));
        if (buyerFeePermille != 0) {
            price = paymentAmt.mul(1000).div((1000 + buyerFeePermille));
            uint256 buyerFee = paymentAmt.sub(price);
            platformFee = buyerFee.add(sellerFee);
        } else {
            price = paymentAmt;
            platformFee = sellerFee;
        }

        // If trade with no enigma NFT royalty fee is 0
        if (buyingAssetAddress == enigmaNFT721Address || buyingAssetAddress == enigmaNFT1155Address) {
            royaltyPermille = ((IRoyaltyAwareNFT(buyingAssetAddress).royaltyFee(tokenId)));
            tokenCreator = ((IRoyaltyAwareNFT(buyingAssetAddress).getCreator(tokenId)));
            royaltyFee = paymentAmt.mul(royaltyPermille).div((1000 + buyerFeePermille));
        } else {
            tokenCreator = address(0);
            royaltyFee = 0;
        }
        assetFee = price.sub(royaltyFee).sub(sellerFee);
        return Fee(platformFee, assetFee, royaltyFee, price, tokenCreator);
    }

    function tradeNFT(Order memory order) internal virtual {
        safeTransferFrom(order.nftType, order.seller, order.buyer, order.nftAddress, order.tokenId, order.qty);
    }

    function safeTransferFrom(
        AssetType nftType,
        address from,
        address to,
        address nftAddress,
        uint256 tokenId,
        uint256 qty
    ) internal virtual {
        nftType == AssetType.ERC721
            ? transferProxy.erc721safeTransferFrom(nftAddress, from, to, tokenId)
            : transferProxy.erc1155safeTransferFrom(nftAddress, from, to, tokenId, qty, "");
    }

    function tradeAssetWithERC20(Order memory order, Fee memory fee) internal virtual {
        tradeNFT(order);
        if (fee.platformFee > 0) {
            // TODO: review if this owner still makes sense
            transferProxy.erc20safeTransferFrom(order.erc20Address, order.buyer, owner(), fee.platformFee);
        }
        if (fee.royaltyFee > 0) {
            transferProxy.erc20safeTransferFrom(order.erc20Address, order.buyer, fee.tokenCreator, fee.royaltyFee);
        }
        transferProxy.erc20safeTransferFrom(order.erc20Address, order.buyer, order.seller, fee.assetFee);
    }

    /**
     * @dev Disable slither warning because there is a nonReentrant check and the address are known
     * https://github.com/crytic/slither/wiki/Detector-Documentation#functions-that-send-ether-to-arbitrary-destinations
     */
    function tradeAssetWithETH(Order memory order, Fee memory fee) internal virtual {
        tradeNFT(order);
        if (fee.platformFee > 0) {
            // TODO: review if we don't need a new field for collecting fees
            // slither-disable-next-line arbitrary-send
            (bool platformSuccess, ) = owner().call{ value: fee.platformFee }("");
            require(platformSuccess, "sending ETH to owner failed");
        }
        if (fee.royaltyFee > 0) {
            // slither-disable-next-line arbitrary-send
            (bool royaltySuccess, ) = fee.tokenCreator.call{ value: fee.royaltyFee }("");
            require(royaltySuccess, "sending ETH to creator failed");
        }
        // slither-disable-next-line arbitrary-send
        (bool sellerSuccess, ) = order.seller.call{ value: fee.assetFee }("");
        require(sellerSuccess, "sending ETH to seller failed");
    }

    /**
     * @notice Verifies if this authorization index has already been processed
     * @param _index of the Authorization signature you want to know it's been processed
     */
    function isAuthProcessed(uint256 _index) public view returns (bool) {
        uint256 wordIndex = _index / 256;
        uint256 bitIndex = _index % 256;
        uint256 processedWord = processedAuthorizationsBitMap[wordIndex];
        uint256 mask = (1 << bitIndex);
        return processedWord & mask == mask;
    }

    /**
     * @notice Sets this authorization index as processed
     * @param _index of the Authorization signature you want to mark as processed
     */
    function setAuthProcessed(uint256 _index) internal {
        uint256 wordIndex = _index / 256;
        uint256 bitIndex = _index % 256;
        processedAuthorizationsBitMap[wordIndex] = processedAuthorizationsBitMap[wordIndex] | (1 << bitIndex);
    }

    /*********************
     ** PUBLIC FUNCTIONS *
     *********************/

    function buyAsset(Order memory order, Sign memory sign) public returns (bool) {
        Fee memory fee = getFees(order.amount, order.nftAddress, order.tokenId);
        require((fee.price >= order.unitPrice * order.qty), "Paid invalid amount");
        verifySellerSignature(order.seller, order.tokenId, order.unitPrice, order.erc20Address, order.nftAddress, sign);
        order.buyer = msg.sender;
        emit BuyAsset(order.seller, order.tokenId, order.qty, msg.sender);
        tradeAssetWithERC20(order, fee);
        return true;
    }

    function buyAssetWithETH(Order memory order, Sign memory sign) public payable nonReentrant returns (bool) {
        require(order.amount == msg.value, "Paid invalid ETH amount");
        Fee memory fee = getFees(order.amount, order.nftAddress, order.tokenId);
        require((fee.price >= order.unitPrice * order.qty), "Paid invalid amount");
        verifySellerSignature(order.seller, order.tokenId, order.unitPrice, address(0), order.nftAddress, sign);
        order.buyer = msg.sender;
        emit BuyAsset(order.seller, order.tokenId, order.qty, msg.sender);
        tradeAssetWithETH(order, fee);
        return true;
    }

    function executeBid(Order memory order, Sign memory sign) public returns (bool) {
        Fee memory fee = getFees(order.amount, order.nftAddress, order.tokenId);
        verifyBuyerSignature(
            order.buyer,
            order.tokenId,
            order.amount,
            order.erc20Address,
            order.nftAddress,
            order.qty,
            sign
        );
        order.seller = msg.sender;
        emit ExecuteBid(msg.sender, order.tokenId, order.qty, order.buyer);
        tradeAssetWithERC20(order, fee);
        return true;
    }

    /**
     * @notice Verifies and executes a safe Token withdraw for this sender, if authorized by the custodial
     * @param wr struct with the withdraw information. What asset and how much of it
     * @param sign asset custodial authorization signature
     */
    function withdrawToken(WithdrawRequest memory wr, Sign memory sign) external returns (bool) {
        address assetOwner = msg.sender;
        require(!isAuthProcessed(wr.authId), "Authorization signature already processed");
        // Verifies that this asset custodial, is actually authorizing this user withdraw
        verifyWithdrawSignature(custodialAddress, assetOwner, wr, sign);
        setAuthProcessed(wr.authId);
        safeTransferFrom(wr.assetType, custodialAddress, assetOwner, wr.assetAddress, wr.tokenId, wr.qty);
        emit TokenWithdraw(assetOwner, wr.authId, wr.tokenId, wr.qty);
        return true;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[1000] private __gap;
}

File 22 of 79 : IERC20.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

File 23 of 79 : ReentrancyGuardUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;
import "../proxy/Initializable.sol";

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuardUpgradeable is Initializable {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    function __ReentrancyGuard_init() internal initializer {
        __ReentrancyGuard_init_unchained();
    }

    function __ReentrancyGuard_init_unchained() internal initializer {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
    uint256[49] private __gap;
}

File 24 of 79 : ITransferProxy.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

interface ITransferProxy {
    function erc721safeTransferFrom(
        address token,
        address from,
        address to,
        uint256 tokenId
    ) external;

    function erc1155safeTransferFrom(
        address token,
        address from,
        address to,
        uint256 id,
        uint256 value,
        bytes calldata data
    ) external;

    function erc20safeTransferFrom(
        address token,
        address from,
        address to,
        uint256 value
    ) external;
}

File 25 of 79 : TransferProxy.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts-upgradeable/token/ERC721/IERC721Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC1155/IERC1155Upgradeable.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "./interfaces/ITransferProxy.sol";

contract TransferProxy is ITransferProxy {
    event OperatorChanged(address indexed from, address indexed to);
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    address public owner;
    address public operator;

    constructor() {
        owner = msg.sender;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */

    modifier onlyOwner() {
        require(owner == msg.sender, "Ownable: caller is not the owner");
        _;
    }

    modifier onlyOperator() {
        require(operator == msg.sender, "OperatorRole: caller does not have the Operator role");
        _;
    }

    /** change the OperatorRole from contract creator address to trade contractaddress
            @param _operator :trade address 
        */

    function changeOperator(address _operator) external onlyOwner returns (bool) {
        require(_operator != address(0), "Operator: new operator is the zero address");
        emit OperatorChanged(operator, _operator);
        operator = _operator;
        return true;
    }

    /** change the Ownership from current owner to newOwner address
        @param newOwner : newOwner address */

    function ownerTransfership(address newOwner) external onlyOwner returns (bool) {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(owner, newOwner);
        owner = newOwner;
        return true;
    }

    function erc721safeTransferFrom(
        address token,
        address from,
        address to,
        uint256 tokenId
    ) external override onlyOperator {
        IERC721Upgradeable(token).safeTransferFrom(from, to, tokenId);
    }

    function erc1155safeTransferFrom(
        address token,
        address from,
        address to,
        uint256 tokenId,
        uint256 value,
        bytes calldata data
    ) external override onlyOperator {
        IERC1155Upgradeable(token).safeTransferFrom(from, to, tokenId, value, data);
    }

    function erc20safeTransferFrom(
        address token,
        address from,
        address to,
        uint256 value
    ) external override onlyOperator {
        require(IERC20(token).transferFrom(from, to, value), "failure while transferring");
    }
}

File 26 of 79 : IERC721Upgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

import "../../introspection/IERC165Upgradeable.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721Upgradeable is IERC165Upgradeable {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);

    /**
      * @dev Safely transfers `tokenId` token from `from` to `to`.
      *
      * Requirements:
      *
      * - `from` cannot be the zero address.
      * - `to` cannot be the zero address.
      * - `tokenId` token must exist and be owned by `from`.
      * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
      * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
      *
      * Emits a {Transfer} event.
      */
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external;
}

File 27 of 79 : ERC20.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../../utils/Context.sol";
import "./IERC20.sol";
import "../../math/SafeMath.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
     * a default value of 18.
     *
     * To select a different value for {decimals}, use {_setupDecimals}.
     *
     * All three of these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name_, string memory symbol_) public {
        _name = name_;
        _symbol = symbol_;
        _decimals = 18;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
     * called.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual returns (uint8) {
        return _decimals;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * Requirements:
     *
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Sets {decimals} to a value other than the default one of 18.
     *
     * WARNING: This function should only be called from the constructor. Most
     * applications that interact with token contracts will not expect
     * {decimals} to ever change, and may work incorrectly if it does.
     */
    function _setupDecimals(uint8 decimals_) internal virtual {
        _decimals = decimals_;
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be to transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}

File 28 of 79 : Context.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

File 29 of 79 : SafeMath.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        uint256 c = a + b;
        if (c < a) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b > a) return (false, 0);
        return (true, a - b);
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) return (true, 0);
        uint256 c = a * b;
        if (c / a != b) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a / b);
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a % b);
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) return 0;
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: division by zero");
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: modulo by zero");
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        return a - b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryDiv}.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a % b;
    }
}

File 30 of 79 : ERC721.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../../utils/Context.sol";
import "./IERC721.sol";
import "./IERC721Metadata.sol";
import "./IERC721Enumerable.sol";
import "./IERC721Receiver.sol";
import "../../introspection/ERC165.sol";
import "../../math/SafeMath.sol";
import "../../utils/Address.sol";
import "../../utils/EnumerableSet.sol";
import "../../utils/EnumerableMap.sol";
import "../../utils/Strings.sol";

/**
 * @title ERC721 Non-Fungible Token Standard basic implementation
 * @dev see https://eips.ethereum.org/EIPS/eip-721
 */
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata, IERC721Enumerable {
    using SafeMath for uint256;
    using Address for address;
    using EnumerableSet for EnumerableSet.UintSet;
    using EnumerableMap for EnumerableMap.UintToAddressMap;
    using Strings for uint256;

    // Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
    // which can be also obtained as `IERC721Receiver(0).onERC721Received.selector`
    bytes4 private constant _ERC721_RECEIVED = 0x150b7a02;

    // Mapping from holder address to their (enumerable) set of owned tokens
    mapping (address => EnumerableSet.UintSet) private _holderTokens;

    // Enumerable mapping from token ids to their owners
    EnumerableMap.UintToAddressMap private _tokenOwners;

    // Mapping from token ID to approved address
    mapping (uint256 => address) private _tokenApprovals;

    // Mapping from owner to operator approvals
    mapping (address => mapping (address => bool)) private _operatorApprovals;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Optional mapping for token URIs
    mapping (uint256 => string) private _tokenURIs;

    // Base URI
    string private _baseURI;

    /*
     *     bytes4(keccak256('balanceOf(address)')) == 0x70a08231
     *     bytes4(keccak256('ownerOf(uint256)')) == 0x6352211e
     *     bytes4(keccak256('approve(address,uint256)')) == 0x095ea7b3
     *     bytes4(keccak256('getApproved(uint256)')) == 0x081812fc
     *     bytes4(keccak256('setApprovalForAll(address,bool)')) == 0xa22cb465
     *     bytes4(keccak256('isApprovedForAll(address,address)')) == 0xe985e9c5
     *     bytes4(keccak256('transferFrom(address,address,uint256)')) == 0x23b872dd
     *     bytes4(keccak256('safeTransferFrom(address,address,uint256)')) == 0x42842e0e
     *     bytes4(keccak256('safeTransferFrom(address,address,uint256,bytes)')) == 0xb88d4fde
     *
     *     => 0x70a08231 ^ 0x6352211e ^ 0x095ea7b3 ^ 0x081812fc ^
     *        0xa22cb465 ^ 0xe985e9c5 ^ 0x23b872dd ^ 0x42842e0e ^ 0xb88d4fde == 0x80ac58cd
     */
    bytes4 private constant _INTERFACE_ID_ERC721 = 0x80ac58cd;

    /*
     *     bytes4(keccak256('name()')) == 0x06fdde03
     *     bytes4(keccak256('symbol()')) == 0x95d89b41
     *     bytes4(keccak256('tokenURI(uint256)')) == 0xc87b56dd
     *
     *     => 0x06fdde03 ^ 0x95d89b41 ^ 0xc87b56dd == 0x5b5e139f
     */
    bytes4 private constant _INTERFACE_ID_ERC721_METADATA = 0x5b5e139f;

    /*
     *     bytes4(keccak256('totalSupply()')) == 0x18160ddd
     *     bytes4(keccak256('tokenOfOwnerByIndex(address,uint256)')) == 0x2f745c59
     *     bytes4(keccak256('tokenByIndex(uint256)')) == 0x4f6ccce7
     *
     *     => 0x18160ddd ^ 0x2f745c59 ^ 0x4f6ccce7 == 0x780e9d63
     */
    bytes4 private constant _INTERFACE_ID_ERC721_ENUMERABLE = 0x780e9d63;

    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    constructor (string memory name_, string memory symbol_) public {
        _name = name_;
        _symbol = symbol_;

        // register the supported interfaces to conform to ERC721 via ERC165
        _registerInterface(_INTERFACE_ID_ERC721);
        _registerInterface(_INTERFACE_ID_ERC721_METADATA);
        _registerInterface(_INTERFACE_ID_ERC721_ENUMERABLE);
    }

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: balance query for the zero address");
        return _holderTokens[owner].length();
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        return _tokenOwners.get(tokenId, "ERC721: owner query for nonexistent token");
    }

    /**
     * @dev See {IERC721Metadata-name}.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev See {IERC721Metadata-symbol}.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");

        string memory _tokenURI = _tokenURIs[tokenId];
        string memory base = baseURI();

        // If there is no base URI, return the token URI.
        if (bytes(base).length == 0) {
            return _tokenURI;
        }
        // If both are set, concatenate the baseURI and tokenURI (via abi.encodePacked).
        if (bytes(_tokenURI).length > 0) {
            return string(abi.encodePacked(base, _tokenURI));
        }
        // If there is a baseURI but no tokenURI, concatenate the tokenID to the baseURI.
        return string(abi.encodePacked(base, tokenId.toString()));
    }

    /**
    * @dev Returns the base URI set via {_setBaseURI}. This will be
    * automatically added as a prefix in {tokenURI} to each token's URI, or
    * to the token ID if no specific URI is set for that token ID.
    */
    function baseURI() public view virtual returns (string memory) {
        return _baseURI;
    }

    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
        return _holderTokens[owner].at(index);
    }

    /**
     * @dev See {IERC721Enumerable-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        // _tokenOwners are indexed by tokenIds, so .length() returns the number of tokenIds
        return _tokenOwners.length();
    }

    /**
     * @dev See {IERC721Enumerable-tokenByIndex}.
     */
    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
        (uint256 tokenId, ) = _tokenOwners.at(index);
        return tokenId;
    }

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721.ownerOf(tokenId);
        require(to != owner, "ERC721: approval to current owner");

        require(_msgSender() == owner || ERC721.isApprovedForAll(owner, _msgSender()),
            "ERC721: approve caller is not owner nor approved for all"
        );

        _approve(to, tokenId);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), "ERC721: approved query for nonexistent token");

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        require(operator != _msgSender(), "ERC721: approve to caller");

        _operatorApprovals[_msgSender()][operator] = approved;
        emit ApprovalForAll(_msgSender(), operator, approved);
    }

    /**
     * @dev See {IERC721-isApprovedForAll}.
     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(address from, address to, uint256 tokenId) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");

        _transfer(from, to, tokenId);
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory _data) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        _safeTransfer(from, to, tokenId, _data);
    }

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * `_data` is additional data, it has no specified format and it is sent in call to `to`.
     *
     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
     * implement alternative mechanisms to perform token transfer, such as signature-based.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeTransfer(address from, address to, uint256 tokenId, bytes memory _data) internal virtual {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted (`_mint`),
     * and stop existing when they are burned (`_burn`).
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _tokenOwners.contains(tokenId);
    }

    /**
     * @dev Returns whether `spender` is allowed to manage `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        require(_exists(tokenId), "ERC721: operator query for nonexistent token");
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || ERC721.isApprovedForAll(owner, spender));
    }

    /**
     * @dev Safely mints `tokenId` and transfers it to `to`.
     *
     * Requirements:
     d*
     * - `tokenId` must not exist.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(address to, uint256 tokenId) internal virtual {
        _safeMint(to, tokenId, "");
    }

    /**
     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
     */
    function _safeMint(address to, uint256 tokenId, bytes memory _data) internal virtual {
        _mint(to, tokenId);
        require(_checkOnERC721Received(address(0), to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    /**
     * @dev Mints `tokenId` and transfers it to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - `to` cannot be the zero address.
     *
     * Emits a {Transfer} event.
     */
    function _mint(address to, uint256 tokenId) internal virtual {
        require(to != address(0), "ERC721: mint to the zero address");
        require(!_exists(tokenId), "ERC721: token already minted");

        _beforeTokenTransfer(address(0), to, tokenId);

        _holderTokens[to].add(tokenId);

        _tokenOwners.set(tokenId, to);

        emit Transfer(address(0), to, tokenId);
    }

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721.ownerOf(tokenId); // internal owner

        _beforeTokenTransfer(owner, address(0), tokenId);

        // Clear approvals
        _approve(address(0), tokenId);

        // Clear metadata (if any)
        if (bytes(_tokenURIs[tokenId]).length != 0) {
            delete _tokenURIs[tokenId];
        }

        _holderTokens[owner].remove(tokenId);

        _tokenOwners.remove(tokenId);

        emit Transfer(owner, address(0), tokenId);
    }

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    function _transfer(address from, address to, uint256 tokenId) internal virtual {
        require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own"); // internal owner
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId);

        // Clear approvals from the previous owner
        _approve(address(0), tokenId);

        _holderTokens[from].remove(tokenId);
        _holderTokens[to].add(tokenId);

        _tokenOwners.set(tokenId, to);

        emit Transfer(from, to, tokenId);
    }

    /**
     * @dev Sets `_tokenURI` as the tokenURI of `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _setTokenURI(uint256 tokenId, string memory _tokenURI) internal virtual {
        require(_exists(tokenId), "ERC721Metadata: URI set of nonexistent token");
        _tokenURIs[tokenId] = _tokenURI;
    }

    /**
     * @dev Internal function to set the base URI for all token IDs. It is
     * automatically added as a prefix to the value returned in {tokenURI},
     * or to the token ID if {tokenURI} is empty.
     */
    function _setBaseURI(string memory baseURI_) internal virtual {
        _baseURI = baseURI_;
    }

    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
     * The call is not executed if the target address is not a contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param _data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkOnERC721Received(address from, address to, uint256 tokenId, bytes memory _data)
        private returns (bool)
    {
        if (!to.isContract()) {
            return true;
        }
        bytes memory returndata = to.functionCall(abi.encodeWithSelector(
            IERC721Receiver(to).onERC721Received.selector,
            _msgSender(),
            from,
            tokenId,
            _data
        ), "ERC721: transfer to non ERC721Receiver implementer");
        bytes4 retval = abi.decode(returndata, (bytes4));
        return (retval == _ERC721_RECEIVED);
    }

    function _approve(address to, uint256 tokenId) private {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721.ownerOf(tokenId), to, tokenId); // internal owner
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal virtual { }
}

File 31 of 79 : IERC721.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

import "../../introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);

    /**
      * @dev Safely transfers `tokenId` token from `from` to `to`.
      *
      * Requirements:
      *
      * - `from` cannot be the zero address.
      * - `to` cannot be the zero address.
      * - `tokenId` token must exist and be owned by `from`.
      * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
      * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
      *
      * Emits a {Transfer} event.
      */
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external;
}

File 32 of 79 : IERC721Metadata.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

import "./IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {

    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}

File 33 of 79 : IERC721Enumerable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

import "./IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {

    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}

File 34 of 79 : IERC721Receiver.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(address operator, address from, uint256 tokenId, bytes calldata data) external returns (bytes4);
}

File 35 of 79 : ERC165.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./IERC165.sol";

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts may inherit from this and call {_registerInterface} to declare
 * their support of an interface.
 */
abstract contract ERC165 is IERC165 {
    /*
     * bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7
     */
    bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;

    /**
     * @dev Mapping of interface ids to whether or not it's supported.
     */
    mapping(bytes4 => bool) private _supportedInterfaces;

    constructor () internal {
        // Derived contracts need only register support for their own interfaces,
        // we register support for ERC165 itself here
        _registerInterface(_INTERFACE_ID_ERC165);
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     *
     * Time complexity O(1), guaranteed to always use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return _supportedInterfaces[interfaceId];
    }

    /**
     * @dev Registers the contract as an implementer of the interface defined by
     * `interfaceId`. Support of the actual ERC165 interface is automatic and
     * registering its interface id is not required.
     *
     * See {IERC165-supportsInterface}.
     *
     * Requirements:
     *
     * - `interfaceId` cannot be the ERC165 invalid interface (`0xffffffff`).
     */
    function _registerInterface(bytes4 interfaceId) internal virtual {
        require(interfaceId != 0xffffffff, "ERC165: invalid interface id");
        _supportedInterfaces[interfaceId] = true;
    }
}

File 36 of 79 : Address.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

File 37 of 79 : EnumerableSet.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;

        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping (bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) { // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

            bytes32 lastvalue = set._values[lastIndex];

            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastvalue;
            // Update the index for the moved value
            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        require(set._values.length > index, "EnumerableSet: index out of bounds");
        return set._values[index];
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }


    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
}

File 38 of 79 : EnumerableMap.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Library for managing an enumerable variant of Solidity's
 * https://solidity.readthedocs.io/en/latest/types.html#mapping-types[`mapping`]
 * type.
 *
 * Maps have the following properties:
 *
 * - Entries are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Entries are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableMap for EnumerableMap.UintToAddressMap;
 *
 *     // Declare a set state variable
 *     EnumerableMap.UintToAddressMap private myMap;
 * }
 * ```
 *
 * As of v3.0.0, only maps of type `uint256 -> address` (`UintToAddressMap`) are
 * supported.
 */
library EnumerableMap {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Map type with
    // bytes32 keys and values.
    // The Map implementation uses private functions, and user-facing
    // implementations (such as Uint256ToAddressMap) are just wrappers around
    // the underlying Map.
    // This means that we can only create new EnumerableMaps for types that fit
    // in bytes32.

    struct MapEntry {
        bytes32 _key;
        bytes32 _value;
    }

    struct Map {
        // Storage of map keys and values
        MapEntry[] _entries;

        // Position of the entry defined by a key in the `entries` array, plus 1
        // because index 0 means a key is not in the map.
        mapping (bytes32 => uint256) _indexes;
    }

    /**
     * @dev Adds a key-value pair to a map, or updates the value for an existing
     * key. O(1).
     *
     * Returns true if the key was added to the map, that is if it was not
     * already present.
     */
    function _set(Map storage map, bytes32 key, bytes32 value) private returns (bool) {
        // We read and store the key's index to prevent multiple reads from the same storage slot
        uint256 keyIndex = map._indexes[key];

        if (keyIndex == 0) { // Equivalent to !contains(map, key)
            map._entries.push(MapEntry({ _key: key, _value: value }));
            // The entry is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            map._indexes[key] = map._entries.length;
            return true;
        } else {
            map._entries[keyIndex - 1]._value = value;
            return false;
        }
    }

    /**
     * @dev Removes a key-value pair from a map. O(1).
     *
     * Returns true if the key was removed from the map, that is if it was present.
     */
    function _remove(Map storage map, bytes32 key) private returns (bool) {
        // We read and store the key's index to prevent multiple reads from the same storage slot
        uint256 keyIndex = map._indexes[key];

        if (keyIndex != 0) { // Equivalent to contains(map, key)
            // To delete a key-value pair from the _entries array in O(1), we swap the entry to delete with the last one
            // in the array, and then remove the last entry (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = keyIndex - 1;
            uint256 lastIndex = map._entries.length - 1;

            // When the entry to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

            MapEntry storage lastEntry = map._entries[lastIndex];

            // Move the last entry to the index where the entry to delete is
            map._entries[toDeleteIndex] = lastEntry;
            // Update the index for the moved entry
            map._indexes[lastEntry._key] = toDeleteIndex + 1; // All indexes are 1-based

            // Delete the slot where the moved entry was stored
            map._entries.pop();

            // Delete the index for the deleted slot
            delete map._indexes[key];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the key is in the map. O(1).
     */
    function _contains(Map storage map, bytes32 key) private view returns (bool) {
        return map._indexes[key] != 0;
    }

    /**
     * @dev Returns the number of key-value pairs in the map. O(1).
     */
    function _length(Map storage map) private view returns (uint256) {
        return map._entries.length;
    }

   /**
    * @dev Returns the key-value pair stored at position `index` in the map. O(1).
    *
    * Note that there are no guarantees on the ordering of entries inside the
    * array, and it may change when more entries are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Map storage map, uint256 index) private view returns (bytes32, bytes32) {
        require(map._entries.length > index, "EnumerableMap: index out of bounds");

        MapEntry storage entry = map._entries[index];
        return (entry._key, entry._value);
    }

    /**
     * @dev Tries to returns the value associated with `key`.  O(1).
     * Does not revert if `key` is not in the map.
     */
    function _tryGet(Map storage map, bytes32 key) private view returns (bool, bytes32) {
        uint256 keyIndex = map._indexes[key];
        if (keyIndex == 0) return (false, 0); // Equivalent to contains(map, key)
        return (true, map._entries[keyIndex - 1]._value); // All indexes are 1-based
    }

    /**
     * @dev Returns the value associated with `key`.  O(1).
     *
     * Requirements:
     *
     * - `key` must be in the map.
     */
    function _get(Map storage map, bytes32 key) private view returns (bytes32) {
        uint256 keyIndex = map._indexes[key];
        require(keyIndex != 0, "EnumerableMap: nonexistent key"); // Equivalent to contains(map, key)
        return map._entries[keyIndex - 1]._value; // All indexes are 1-based
    }

    /**
     * @dev Same as {_get}, with a custom error message when `key` is not in the map.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {_tryGet}.
     */
    function _get(Map storage map, bytes32 key, string memory errorMessage) private view returns (bytes32) {
        uint256 keyIndex = map._indexes[key];
        require(keyIndex != 0, errorMessage); // Equivalent to contains(map, key)
        return map._entries[keyIndex - 1]._value; // All indexes are 1-based
    }

    // UintToAddressMap

    struct UintToAddressMap {
        Map _inner;
    }

    /**
     * @dev Adds a key-value pair to a map, or updates the value for an existing
     * key. O(1).
     *
     * Returns true if the key was added to the map, that is if it was not
     * already present.
     */
    function set(UintToAddressMap storage map, uint256 key, address value) internal returns (bool) {
        return _set(map._inner, bytes32(key), bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the key was removed from the map, that is if it was present.
     */
    function remove(UintToAddressMap storage map, uint256 key) internal returns (bool) {
        return _remove(map._inner, bytes32(key));
    }

    /**
     * @dev Returns true if the key is in the map. O(1).
     */
    function contains(UintToAddressMap storage map, uint256 key) internal view returns (bool) {
        return _contains(map._inner, bytes32(key));
    }

    /**
     * @dev Returns the number of elements in the map. O(1).
     */
    function length(UintToAddressMap storage map) internal view returns (uint256) {
        return _length(map._inner);
    }

   /**
    * @dev Returns the element stored at position `index` in the set. O(1).
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintToAddressMap storage map, uint256 index) internal view returns (uint256, address) {
        (bytes32 key, bytes32 value) = _at(map._inner, index);
        return (uint256(key), address(uint160(uint256(value))));
    }

    /**
     * @dev Tries to returns the value associated with `key`.  O(1).
     * Does not revert if `key` is not in the map.
     *
     * _Available since v3.4._
     */
    function tryGet(UintToAddressMap storage map, uint256 key) internal view returns (bool, address) {
        (bool success, bytes32 value) = _tryGet(map._inner, bytes32(key));
        return (success, address(uint160(uint256(value))));
    }

    /**
     * @dev Returns the value associated with `key`.  O(1).
     *
     * Requirements:
     *
     * - `key` must be in the map.
     */
    function get(UintToAddressMap storage map, uint256 key) internal view returns (address) {
        return address(uint160(uint256(_get(map._inner, bytes32(key)))));
    }

    /**
     * @dev Same as {get}, with a custom error message when `key` is not in the map.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryGet}.
     */
    function get(UintToAddressMap storage map, uint256 key, string memory errorMessage) internal view returns (address) {
        return address(uint160(uint256(_get(map._inner, bytes32(key), errorMessage))));
    }
}

File 39 of 79 : Strings.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    /**
     * @dev Converts a `uint256` to its ASCII `string` representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        uint256 index = digits - 1;
        temp = value;
        while (temp != 0) {
            buffer[index--] = bytes1(uint8(48 + temp % 10));
            temp /= 10;
        }
        return string(buffer);
    }
}

File 40 of 79 : IERC165.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

File 41 of 79 : AccessControl.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../utils/EnumerableSet.sol";
import "../utils/Address.sol";
import "../utils/Context.sol";

/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context {
    using EnumerableSet for EnumerableSet.AddressSet;
    using Address for address;

    struct RoleData {
        EnumerableSet.AddressSet members;
        bytes32 adminRole;
    }

    mapping (bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);

    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view returns (bool) {
        return _roles[role].members.contains(account);
    }

    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) public view returns (uint256) {
        return _roles[role].members.length();
    }

    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) public view returns (address) {
        return _roles[role].members.at(index);
    }

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view returns (bytes32) {
        return _roles[role].adminRole;
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to grant");

        _grantRole(role, account);
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to revoke");

        _revokeRole(role, account);
    }

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) public virtual {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");

        _revokeRole(role, account);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }

    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        emit RoleAdminChanged(role, _roles[role].adminRole, adminRole);
        _roles[role].adminRole = adminRole;
    }

    function _grantRole(bytes32 role, address account) private {
        if (_roles[role].members.add(account)) {
            emit RoleGranted(role, account, _msgSender());
        }
    }

    function _revokeRole(bytes32 role, address account) private {
        if (_roles[role].members.remove(account)) {
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}

File 42 of 79 : Ownable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../utils/Context.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

File 43 of 79 : TransferGatekepper.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/access/Ownable.sol";
import "../interfaces/ITransferGatekeeper.sol";
import "../interfaces/IWhitelist.sol";
import "../interfaces/IWhitelistHandler.sol";
import "../interfaces/IWyvernProxyRegistry.sol";

/// @title TransferGatekeeper
///
/// @dev This contract abstracts the transfer gatekeeping implementation to the caller, ie, ERC721 & ERC1155 tokens
///			 The logic can be replaced and the `canTransfer` will invoke the proper target function. It's important
///			 to mention that no storage is shared between this contract and the corresponding implementation
///			 call is used instead of delegate call to avoid different implementations storage compatibility.
contract TransferGatekeeper is ITransferGatekeeper, IWhitelistHandler, Ownable {
    event WhitelistChanged(address indexed _oldImplementation, address indexed _newImplementation);
    event RegistryChanged(address indexed _oldImplementation, address indexed _newImplementation);

    // The address of the whitelist implementation
    IWhitelist public whitelist;

    // The Wyvern compatible registry on wich to very user-proxy
    IWyvernProxyRegistry public registry;

    // Allowd the owner to enable/disable the registry
    bool public useRegistry;

    constructor(IWhitelist _whitelist) {
        require(address(_whitelist) != address(0), "invalid address");
        whitelist = _whitelist;
        useRegistry = false;
    }

    /**
        @notice Legacy function to support retrocompatibility on migration
                from WhitelistProxy to TransferGatekeeper
     */
    function canTransfer(address _proxy) external view returns (bool) {
        return whitelist.canTransfer(_proxy);
    }

    /**
     * @inheritdoc ITransferGatekeeper
     */
    function canTransfer(
        address _from,
        address,
        address _proxy,
        bytes memory
    ) external view override returns (bool) {
        return
            _from == _proxy || // the owner is executing the transfer
            whitelist.canTransfer(_proxy) || // the executor is whitelisted
            canTransferFromProxy(_from, _proxy); // the executor is an authorized proxy
    }

    function canTransferFromProxy(address _from, address _proxy) internal view returns (bool) {
        if (!useRegistry || address(registry) == address(0)) return false;
        address registryProxy = registry.proxies(_from);
        return address(registryProxy) == _proxy;
    }

    /**
     * @notice Sets the new address on wich to check whitelisting and enables its use
     * @param _registry the address of the new proxy registry implementation
     */
    function setRegistry(IWyvernProxyRegistry _registry) external onlyOwner {
        require(address(_registry) != address(0), "setRegistry: invalid address");
        emit RegistryChanged(address(registry), address(_registry));
        registry = _registry;
        setUseRegistry(true);
    }

    /**
     * @notice Enables/disable the registry use
     * @param _useRegistry true if you want to enable it
     */
    function setUseRegistry(bool _useRegistry) public onlyOwner {
        require(address(registry) != address(0), "Cannot change registry use with empty address");
        useRegistry = _useRegistry;
    }

    /**
     * @notice Sets the new address on wich to check whitelisting
     * @param _whitelist the address of the new whitelist implementation
     */
    function setWhitelist(IWhitelist _whitelist) external override onlyOwner {
        require(address(_whitelist) != address(0), "updateWhitelist: invalid address");
        emit WhitelistChanged(address(whitelist), address(_whitelist));
        whitelist = _whitelist;
    }
}

File 44 of 79 : IWhitelist.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

/// All the whitelists logics that want to be used in the NFTs contracts must implement this interface.
///
/// By implementing this interface, can be transfered.
///

interface IWhitelist {
    /**
     * @param _who the address that wants to transfer a NFT
     * @dev Returns true if address has permission to transfer a NFT
     */
    function canTransfer(address _who) external view returns (bool);
}

File 45 of 79 : IWhitelistHandler.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;
import "./IWhitelist.sol";

/// @title IWhitelistHandler

interface IWhitelistHandler {
    /**
     * @param _whitelist the contract that implements IWhitelist
     */
    function setWhitelist(IWhitelist _whitelist) external;
}

File 46 of 79 : IWyvernProxyRegistry.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

/**
 * @title IWyvernProxyRegistry
 * @author Wyvern Protocol Developers
 */
interface IWyvernProxyRegistry {
    /**
     * Returns The Wyvern Proxy for the given owner
     * @param owner the owner of the Proxy
     * @dev based on Apr '22 https://github.com/wyvernprotocol/wyvern-v3
     */
    function proxies(address owner) external view returns (address);
}

File 47 of 79 : TestsWyvernProxyRegistry.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "../interfaces/IWyvernProxyRegistry.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC721/IERC721Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC1155/IERC1155Upgradeable.sol";

contract TestsWyvernProxy {
    function proxyType() public pure returns (uint256 proxyTypeId) {
        return 2;
    }

    function erc721TransferFrom(
        address token,
        address from,
        address to,
        uint256 tokenId
    ) external {
        IERC721Upgradeable(token).transferFrom(from, to, tokenId);
    }

    function erc1155TransferFrom(
        address token,
        address from,
        address to,
        uint256 tokenId,
        uint256 value,
        bytes memory data
    ) external {
        IERC1155Upgradeable(token).safeTransferFrom(from, to, tokenId, value, data);
    }

    function erc1155BatchTransferFrom(
        address token,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) external {
        IERC1155Upgradeable(token).safeBatchTransferFrom(from, to, ids, amounts, data);
    }
}

contract TestsWyvernProxyRegistry {
    /* Authenticated proxies by user. */
    mapping(address => TestsWyvernProxy) public proxies;

    function registerProxy() public returns (TestsWyvernProxy proxy) {
        require(address(proxies[msg.sender]) == address(0), "Proxy mast not me initilized already");
        proxy = new TestsWyvernProxy();
        proxies[msg.sender] = proxy;
        return proxy;
    }
}

File 48 of 79 : NFTMarketReserveAuction.sol
// SPDX-License-Identifier: MIT OR Apache-2.0

pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

/// @dev Taken from https://github.com/f8n/fnd-protocol/tree/v2.0.3

import "@openzeppelin/contracts-upgradeable/utils/ReentrancyGuardUpgradeable.sol";

import "./NFTMarketAuction.sol";
import "./NFTMarketCore.sol";
import "./SendValueWithFallbackWithdraw.sol";

// The gas limit to send ETH to a single recipient, enough for a contract with a simple receiver.
uint256 constant SEND_VALUE_GAS_LIMIT_SINGLE_RECIPIENT = 20000;

// solhint-disable max-line-length
string constant ReserveAuction_Already_Listed = "ReserveAuction_Already_Listed";
string constant ReserveAuction_Bid_Must_Be_At_Least_Min_Amount = "ReserveAuction_Bid_Must_Be_At_Least_Min_Amount";
string constant ReserveAuction_Cannot_Admin_Cancel_Without_Reason = "ReserveAuction_Cannot_Admin_Cancel_Without_Reason";
string constant ReserveAuction_Cannot_Bid_Lower_Than_Reserve_Price = "ReserveAuction_Cannot_Bid_Lower_Than_Reserve_Price";
string constant ReserveAuction_Cannot_Bid_On_Ended_Auction = "ReserveAuction_Cannot_Bid_On_Ended_Auction";
string constant ReserveAuction_Cannot_Bid_On_Nonexistent_Auction = "ReserveAuction_Cannot_Bid_On_Nonexistent_Auction";
string constant ReserveAuction_Cannot_Cancel_Nonexistent_Auction = "ReserveAuction_Cannot_Cancel_Nonexistent_Auction";
string constant ReserveAuction_Cannot_Finalize_Already_Settled_Auction = "ReserveAuction_Cannot_Finalize_Already_Settled_Auction";
string constant ReserveAuction_Cannot_Finalize_Auction_In_Progress = "ReserveAuction_Cannot_Finalize_Auction_In_Progress";
string constant ReserveAuction_Cannot_Rebid_Over_Outstanding_Bid = "ReserveAuction_Cannot_Rebid_Over_Outstanding_Bid";
string constant ReserveAuction_Cannot_Update_Auction_In_Progress = "ReserveAuction_Cannot_Update_Auction_In_Progress";
string constant ReserveAuction_Subceeds_Min_Duration = "ReserveAuction_Subceeds_Min_Duration";
string constant ReserveAuction_Exceeds_Max_Duration = "ReserveAuction_Exceeds_Max_Duration";
string constant ReserveAuction_Less_Than_Extension_Duration = "ReserveAuction_Less_Than_Extension_Duration";
string constant ReserveAuction_Must_Set_Non_Zero_Reserve_Price = "ReserveAuction_Must_Set_Non_Zero_Reserve_Price";
string constant ReserveAuction_Not_Matching_Bidder = "ReserveAuction_Not_Matching_Bidder";
string constant ReserveAuction_Only_Owner_Can_Update_Auction = "ReserveAuction_Only_Owner_Can_Update_Auction";
string constant ReserveAuction_Price_Already_Set = "ReserveAuction_Price_Already_Set";

// solhint-enable max-line-length

/**
 * @title Allows the owner of an NFT to list it in auction.
 * @notice NFTs in auction are escrowed in the market contract.
 */
abstract contract NFTMarketReserveAuction is
    ReentrancyGuardUpgradeable,
    NFTMarketCore,
    NFTMarketAuction,
    SendValueWithFallbackWithdraw
{
    // Stores the auction configuration for a specific NFT.
    struct ReserveAuction {
        // The address of the NFT contract.
        address nftContract;
        // The id of the NFT.
        uint256 tokenId;
        // The owner of the NFT which listed it in auction.
        address payable seller;
        // The duration for this auction.
        uint256 duration;
        // The extension window for this auction.
        uint256 extensionDuration;
        // The time at which this auction will not accept any new bids.
        // @dev This is `0` until the first bid is placed.
        uint256 endTime;
        // The current highest bidder in this auction.
        // @dev This is `address(0)` until the first bid is placed.
        address payable bidder;
        // The latest amount locked in for this auction. Includes buyerFee.
        // @dev This is set to the reserve price + buyerFee, and then to the highest bid once the auction has started.
        uint256 amount;
        // The buyerFee at the moment the auction was created. Expressed as x1000 (ej: 100 => 10% = 0.1)
        uint8 buyerFeePermille;
        // The sellerFee at the moment the auction was created. Expressed as x1000 (ej: 100 => 10% = 0.1)
        uint8 sellerFeePermille;
    }

    /// @dev The auction configuration for a specific auction id.
    mapping(address => mapping(uint256 => uint256)) internal nftContractToTokenIdToAuctionId;

    /// @dev The auction id for a specific NFT.
    /// @dev This is deleted when an auction is finalized or canceled.
    mapping(uint256 => ReserveAuction) internal auctionIdToAuction;

    /// @dev Minimal value for how long an auction can lasts for once the first bid has been received.
    uint256 internal minDuration;

    /// @dev Maximal value for how long an auction can lasts for once the first bid has been received.
    uint256 internal maxDuration;

    /// @dev The window for auction extensions, any bid placed in the final 15 minutes
    /// of an auction will reset the time remaining to 15 minutes.
    uint256 internal constant EXTENSION_DURATION = 15 minutes;

    /// @dev Caps the max duration that may be configured so that overflows will not occur.
    uint256 internal constant MAX_MAX_DURATION = 1000 days;

    /**
     * @notice Emitted when a bid is placed.
     * @param auctionId The id of the auction this bid was for.
     * @param bidder The address of the bidder.
     * @param amount The amount of the bid.
     * @param endTime The new end time of the auction (which may have been set or extended by this bid).
     */
    event ReserveAuctionBidPlaced(uint256 indexed auctionId, address indexed bidder, uint256 amount, uint256 endTime);
    /**
     * @notice Emitted when an auction is cancelled.
     * @dev This is only possible if the auction has not received any bids.
     * @param auctionId The id of the auction that was cancelled.
     */
    event ReserveAuctionCanceled(uint256 indexed auctionId);
    /**
     * @notice Emitted when an auction is canceled by a Enigma admin.
     * @dev When this occurs, the highest bidder (if there was a bid) is automatically refunded.
     * @param auctionId The id of the auction that was cancelled.
     * @param reason The reason for the cancellation.
     */
    event ReserveAuctionCanceledByAdmin(uint256 indexed auctionId, string reason);
    /**
     * @notice Emitted when an NFT is listed for auction.
     * @param seller The address of the seller.
     * @param nftContract The address of the NFT contract.
     * @param tokenId The id of the NFT.
     * @param duration The duration of the auction (always 24-hours).
     * @param extensionDuration The duration of the auction extension window (always 15-minutes).
     * @param reservePrice The reserve price to kick off the auction.
     * @param bidAmount Reserve price, plus buyerFee. Min amount required to win this auction.
     * @param auctionId The id of the auction that was created.
     */
    event ReserveAuctionCreated(
        address indexed seller,
        address indexed nftContract,
        uint256 indexed tokenId,
        uint256 duration,
        uint256 extensionDuration,
        uint256 reservePrice,
        uint256 bidAmount,
        uint256 auctionId
    );
    /**
     * @notice Emitted when an auction that has already ended is finalized,
     * indicating that the NFT has been transferred and revenue from the sale distributed.
     * @dev The amount of the highest bid / final sale price for this auction is `f8nFee` + `creatorFee` + `ownerRev`.
     * @param auctionId The id of the auction that was finalized.
     * @param seller The address of the seller.
     * @param bidder The address of the highest bidder that won the NFT.
     * @param platformFee The amount of ETH that was sent to Enigma for this sale.
     * @param royaltyFee The amount of ETH that was sent to the creator for this sale.
     * @param sellerRev The amount of ETH that was sent to the sellet for this NFT.
     */
    event ReserveAuctionFinalized(
        uint256 indexed auctionId,
        address indexed seller,
        address indexed bidder,
        uint256 platformFee,
        uint256 royaltyFee,
        uint256 sellerRev
    );
    /**
     * @notice Emitted when the auction's reserve price is changed.
     * @dev This is only possible if the auction has not received any bids.
     * @param auctionId The id of the auction that was updated.
     * @param reservePrice The new reserve price for the auction.
     */
    event ReserveAuctionUpdated(uint256 indexed auctionId, uint256 reservePrice);

    /// @notice Confirms that the reserve price is not zero.
    modifier onlyValidAuctionConfig(uint256 reservePrice) {
        if (reservePrice == 0) {
            revert(ReserveAuction_Must_Set_Non_Zero_Reserve_Price);
        }
        _;
    }

    /// oz-upgrades-unsafe-allow constructor
    // solhint-disable-next-line
    constructor() {}

    /**
     * @notice Configures the duration for auctions.
     * @param _minDuration The min duration for auctions, in seconds.
     * @param _maxDuration The max duration for auctions, in seconds.
     */
    function _initializeNFTMarketReserveAuction(uint256 _minDuration, uint256 _maxDuration) internal {
        if (_maxDuration > MAX_MAX_DURATION) {
            // This ensures that math in this file will not overflow due to a huge duration.
            revert(ReserveAuction_Exceeds_Max_Duration);
        }
        if (_minDuration < EXTENSION_DURATION) {
            // The auction duration configuration must be greater than the extension window of 15 minutes
            revert(ReserveAuction_Less_Than_Extension_Duration);
        }
        minDuration = _minDuration;
        maxDuration = _maxDuration;
    }

    /**
     * @notice Creates an auction for the given NFT.
     * The NFT is held in escrow until the auction is finalized or canceled.
     * buyer and seller fees are locked at creation time
     * @param nftContract The address of the NFT contract.
     * @param tokenId The id of the NFT.
     * @param duration seconds for how long an auction lasts for once the first bid has been received.
     * @param reservePrice The initial reserve price for the auction.
     * @param buyerFeePermille the fee taken from the buyer, expressed in *1000 (ej: 10% = 0.1 => 100)
     * @param sellerFeePermille the fee taken from the saller, expressed in *1000 (ej: 10% = 0.1 => 100)
     */
    function createReserveAuctionFor(
        address nftContract,
        uint256 tokenId,
        uint256 duration,
        uint256 reservePrice,
        uint256 amount,
        uint8 buyerFeePermille,
        uint8 sellerFeePermille
    ) internal {
        uint256 auctionId = nftContractToTokenIdToAuctionId[nftContract][tokenId];
        if (auctionId == 0) {
            // NFT is not in auction
            // If the `msg.sender` is not the owner of the NFT, transferring into escrow should fail.
            _transferToEscrow(nftContract, tokenId);
        } else {
            // Using storage saves gas since most of the data is not needed
            ReserveAuction storage auction = auctionIdToAuction[auctionId];
            if (auction.endTime == 0) {
                revert(ReserveAuction_Already_Listed);
            } else {
                // Auction in progress, confirm the highest bidder is a match
                if (auction.bidder != msg.sender) {
                    revert(ReserveAuction_Not_Matching_Bidder);
                }

                // Finalize auction but leave NFT in escrow, reverts if the auction has not ended
                _finalizeReserveAuction({ auctionId: auctionId, keepInEscrow: true });
            }
        }
        // Get the new Id
        auctionId = _getNextAndIncrementAuctionId();

        // This checks if duration is between acceptable
        if (minDuration > duration) {
            revert(ReserveAuction_Subceeds_Min_Duration);
        }
        if (duration > maxDuration) {
            revert(ReserveAuction_Exceeds_Max_Duration);
        }

        // Store the auction details
        nftContractToTokenIdToAuctionId[nftContract][tokenId] = auctionId;
        auctionIdToAuction[auctionId] = ReserveAuction(
            nftContract,
            tokenId,
            payable(msg.sender),
            duration,
            EXTENSION_DURATION,
            0, // endTime is only known once the reserve price is met
            payable(0), // bidder is only known once a bid has been placed
            amount,
            buyerFeePermille, // fees are locked-in at create time
            sellerFeePermille
        );

        emit ReserveAuctionCreated(
            msg.sender,
            nftContract,
            tokenId,
            duration,
            EXTENSION_DURATION,
            reservePrice,
            amount,
            auctionId
        );
    }

    /**
     * @notice Once the countdown has expired for an auction, anyone can settle the auction.
     * This will send the NFT to the highest bidder and distribute revenue for this sale.
     * @param auctionId The id of the auction to settle.
     */
    function finalizeReserveAuction(uint256 auctionId) external nonReentrant {
        if (auctionIdToAuction[auctionId].endTime == 0) {
            revert(ReserveAuction_Cannot_Finalize_Already_Settled_Auction);
        }
        _finalizeReserveAuction({ auctionId: auctionId, keepInEscrow: false });
    }

    /**
     * @notice Settle an auction that has already ended.
     * This will send the NFT to the highest bidder and distribute revenue for this sale.
     * @param keepInEscrow If true, the NFT will be kept in escrow to save gas by avoiding
     * redundant transfers if the NFT should remain in escrow, such as when the new owner
     * sets a buy price or lists it in a new auction.
     */
    function _finalizeReserveAuction(uint256 auctionId, bool keepInEscrow) internal {
        ReserveAuction memory auction = auctionIdToAuction[auctionId];

        if (auction.endTime >= block.timestamp) {
            revert(ReserveAuction_Cannot_Finalize_Auction_In_Progress);
        }

        // Remove the auction.
        delete nftContractToTokenIdToAuctionId[auction.nftContract][auction.tokenId];
        delete auctionIdToAuction[auctionId];

        if (!keepInEscrow) {
            // The seller was authorized when the auction was originally created
            _transferFromEscrow(auction.nftContract, auction.tokenId, auction.bidder);
        }

        // Distribute revenue for this sale.
        (uint256 platformFee, uint256 royaltyFee, uint256 assetFee) = _distAuctionFunds(auction);

        emit ReserveAuctionFinalized(auctionId, auction.seller, auction.bidder, platformFee, royaltyFee, assetFee);
    }

    function _distAuctionFunds(ReserveAuction memory auction)
        internal
        returns (
            uint256 platformFee,
            uint256 royaltyFee,
            uint256 assetFee
        )
    {
        return _distFunds(auction.nftContract, auction.tokenId, auction.amount, auction.seller);
    }

    /**
     * @notice Allows Enigma to cancel an auction, refunding the bidder and returning the NFT to
     * the seller (if not active buy price set).
     * This should only be used for extreme cases such as DMCA takedown requests.
     * @param auctionId The id of the auction to cancel.
     * @param reason The reason for the cancellation (a required field).
     */
    function adminCancelReserveAuction(uint256 auctionId, string calldata reason) external onlyOwner nonReentrant {
        if (bytes(reason).length == 0) {
            revert(ReserveAuction_Cannot_Admin_Cancel_Without_Reason);
        }
        ReserveAuction memory auction = auctionIdToAuction[auctionId];
        if (auction.amount == 0) {
            revert(ReserveAuction_Cannot_Cancel_Nonexistent_Auction);
        }

        delete nftContractToTokenIdToAuctionId[auction.nftContract][auction.tokenId];
        delete auctionIdToAuction[auctionId];

        // Return the NFT to the owner.
        _transferFromEscrow(auction.nftContract, auction.tokenId, auction.seller);

        if (auction.bidder != address(0)) {
            // Refund the highest bidder if any bids were placed in this auction.
            _sendValueWithFallbackWithdraw(auction.bidder, auction.amount, SEND_VALUE_GAS_LIMIT_SINGLE_RECIPIENT);
        }

        emit ReserveAuctionCanceledByAdmin(auctionId, reason);
    }

    /**
     * @notice If an auction has been created but has not yet received bids, it may be canceled by the seller.
     * @dev The NFT is transferred back to the owner unless there is still a buy price set.
     * @param auctionId The id of the auction to cancel.
     */
    function cancelReserveAuction(uint256 auctionId) external nonReentrant {
        ReserveAuction memory auction = auctionIdToAuction[auctionId];
        if (auction.amount == 0) {
            revert(ReserveAuction_Cannot_Cancel_Nonexistent_Auction);
        }
        if (auction.seller != msg.sender) {
            revert(ReserveAuction_Only_Owner_Can_Update_Auction);
        }
        if (auction.endTime != 0) {
            revert(ReserveAuction_Cannot_Update_Auction_In_Progress);
        }

        // Remove the auction.
        delete nftContractToTokenIdToAuctionId[auction.nftContract][auction.tokenId];
        delete auctionIdToAuction[auctionId];

        // Transfer the NFT.
        _transferFromEscrow(auction.nftContract, auction.tokenId, auction.seller);

        emit ReserveAuctionCanceled(auctionId);
    }

    /**
     * @notice Place a bid in an auction.
     * A bidder may place a bid which is at least the value defined by `getMinBidAmount`.
     * If this is the first bid on the auction, the countdown will begin.
     * If there is already an outstanding bid, the previous bidder will be refunded at this time
     * and if the bid is placed in the final moments of the auction, the countdown may be extended.
     * @param auctionId The id of the auction to bid on.
     */
    /* solhint-disable-next-line code-complexity */
    function placeBid(uint256 auctionId) external payable nonReentrant {
        ReserveAuction storage auction = auctionIdToAuction[auctionId];

        if (auction.amount == 0) {
            // No auction found
            revert(ReserveAuction_Cannot_Bid_On_Nonexistent_Auction);
        }

        uint256 endTime = auction.endTime;
        if (endTime == 0) {
            // This is the first bid, kicking off the auction.

            if (msg.value < auction.amount) {
                // The bid must be >= the reserve price.
                revert(ReserveAuction_Cannot_Bid_Lower_Than_Reserve_Price);
            }

            // Store the bid details.
            auction.amount = msg.value;
            auction.bidder = payable(msg.sender);

            // On the first bid, set the endTime to now + duration.
            // Duration is always less than MAX MAX, so the below can't overflow.
            endTime = block.timestamp + auction.duration;

            auction.endTime = endTime;
        } else {
            if (endTime < block.timestamp) {
                // The auction has already ended.
                revert(ReserveAuction_Cannot_Bid_On_Ended_Auction);
            } else if (auction.bidder == msg.sender) {
                // We currently do not allow a bidder to increase their bid unless another user has outbid them first.
                revert(ReserveAuction_Cannot_Rebid_Over_Outstanding_Bid);
            } else {
                uint256 minIncrement = _getMinIncrement(auction.amount);
                if (msg.value < minIncrement) {
                    // If this bid outbids another, it must be at least 10% greater than the last bid.
                    revert(ReserveAuction_Bid_Must_Be_At_Least_Min_Amount);
                }
            }

            // Cache and update bidder state
            uint256 originalAmount = auction.amount;
            address payable originalBidder = auction.bidder;
            auction.amount = msg.value;
            auction.bidder = payable(msg.sender);

            // When a bid outbids another, check to see if a time extension should apply.
            // We confirmed that the auction has not ended, so endTime is always >= the current timestamp.
            // Current time plus extension duration (always 15 mins) cannot overflow.
            uint256 endTimeWithExtension = block.timestamp + EXTENSION_DURATION;
            if (endTime < endTimeWithExtension) {
                endTime = endTimeWithExtension;
                auction.endTime = endTime;
            }
            // Refund the previous bidder
            _sendValueWithFallbackWithdraw(originalBidder, originalAmount, SEND_VALUE_GAS_LIMIT_SINGLE_RECIPIENT);
        }
        emit ReserveAuctionBidPlaced(auctionId, msg.sender, msg.value, endTime);
    }

    /**
     * @notice If an auction has been created but has not yet received bids, the reservePrice may be
     * changed by the seller.
     * @param auctionId The id of the auction to change.
     * @param reservePrice The new reserve price for this auction.
     */
    function updateReserveAuction(uint256 auctionId, uint256 reservePrice)
        external
        onlyValidAuctionConfig(reservePrice)
    {
        ReserveAuction storage auction = auctionIdToAuction[auctionId];
        if (auction.seller != msg.sender) {
            revert(ReserveAuction_Only_Owner_Can_Update_Auction);
        } else if (auction.endTime != 0) {
            revert(ReserveAuction_Cannot_Update_Auction_In_Progress);
        }

        // get the amount, including buyer fee for this reserve price
        uint256 amount = applyBuyerFee(reservePrice, auction.buyerFeePermille);
        if (auction.amount == amount) revert(ReserveAuction_Price_Already_Set);

        // Update the current reserve price.
        auction.amount = amount;

        emit ReserveAuctionUpdated(auctionId, reservePrice);
    }

    /**
     * @notice Returns the minimum amount a bidder must spend to participate in an auction.
     * Bids must be greater than or equal to this value or they will revert.
     * @param auctionId The id of the auction to check.
     * @return minimum The minimum amount for a bid to be accepted.
     */
    function getMinBidAmount(uint256 auctionId) external view returns (uint256 minimum) {
        ReserveAuction storage auction = auctionIdToAuction[auctionId];
        if (auction.endTime == 0) {
            return auction.amount;
        }
        return _getMinIncrement(auction.amount);
    }

    /**
     * @notice Returns auction details for a given auctionId.
     * @param auctionId The id of the auction to lookup.
     * @return auction The auction details.
     */
    function getReserveAuction(uint256 auctionId) external view returns (ReserveAuction memory auction) {
        return auctionIdToAuction[auctionId];
    }

    /**
     * @notice Returns the auctionId for a given NFT, or 0 if no auction is found.
     * @dev If an auction is canceled, it will not be returned. However the auction may be over
     *  and pending finalization.
     * @param nftContract The address of the NFT contract.
     * @param tokenId The id of the NFT.
     * @return auctionId The id of the auction, or 0 if no auction is found.
     */
    function getReserveAuctionIdFor(address nftContract, uint256 tokenId) external view returns (uint256 auctionId) {
        auctionId = nftContractToTokenIdToAuctionId[nftContract][tokenId];
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[1000] private __gap;
}

File 49 of 79 : NFTMarketAuction.sol
// SPDX-License-Identifier: MIT OR Apache-2.0

pragma solidity ^0.7.6;

/// @dev Taken from https://github.com/f8n/fnd-protocol/tree/v2.0.3

/**
 * @title An abstraction layer for auctions.
 * @dev This contract can be expanded with reusable calls and data as more auction types are added.
 */
abstract contract NFTMarketAuction {
    /**
     * @dev A global id for auctions of any type.
     */
    uint256 private nextAuctionId;

    /**
     * @notice Called once to configure the contract after the initial proxy deployment.
     * @dev This sets the initial auction id to 1, making the first auction cheaper
     * and id 0 represents no auction found.
     */
    function _initializeNFTMarketAuction() internal {
        nextAuctionId = 1;
    }

    /**
     * @notice Returns id to assign to the next auction.
     */
    function _getNextAndIncrementAuctionId() internal returns (uint256) {
        // AuctionId cannot overflow 256 bits.
        return nextAuctionId++;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[1000] private __gap;
}

File 50 of 79 : NFTMarketCore.sol
// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity ^0.7.6;

/// @dev Taken from https://github.com/f8n/fnd-protocol/tree/v2.0.3

import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/math/SafeMathUpgradeable.sol";

/**
 * @title A place for common modifiers and functions used by various NFTMarket mixins, if any.
 * @dev This also leaves a gap which can be used to add a new mixin to the top of the inheritance tree.
 */
abstract contract NFTMarketCore is OwnableUpgradeable {
    using SafeMathUpgradeable for uint256;

    /// @notice Emitted when owner has updated the minIncrementPermille
    event MinIncrementPermilleUpdated(uint16 prevValue, uint16 newValue);

    /// @dev The minimum required when making an offer or placing a bid. Ej: 100 => 0.1 => 10%
    uint16 public minIncrementPermille;

    /**
     * @param _minIncrementPermille The increment to outbid. Ej: 100 => 0.1 => 10%
     */
    function _initializeNFTMarketCore(uint16 _minIncrementPermille) internal {
        minIncrementPermille = _minIncrementPermille;
    }

    function setMinIncrementPermille(uint16 _minIncrementPermille) external onlyOwner {
        emit MinIncrementPermilleUpdated(minIncrementPermille, _minIncrementPermille);
        minIncrementPermille = _minIncrementPermille;
    }

    /**
     * @notice Transfers the NFT from escrow and clears any state tracking this escrowed NFT.
     */
    function _transferFromEscrow(
        address nftContract,
        uint256 tokenId,
        address recipient
    ) internal virtual;

    /**
     * @notice Transfers an NFT into escrow
     */
    function _transferToEscrow(address nftContract, uint256 tokenId) internal virtual;

    /**
     * @notice Applies fees and distributes funds for a finalized market operation.
     * For all creator, platforma and seller.
     * @param nftContract The address of the NFT contract.
     * @param tokenId The id of the NFT.
     * @param amount Reserve price, plus buyerFee.
     * @param seller The address of the seller.
     * @return platformFee Platform share total from the sale, both taken from the buyer and seller
     * @return royaltyFee Rayalty fee distributed to owner/s
     * @return assetFee Total received bu the saller
     */
    function _distFunds(
        address nftContract,
        uint256 tokenId,
        uint256 amount,
        address payable seller
    )
        internal
        virtual
        returns (
            uint256 platformFee,
            uint256 royaltyFee,
            uint256 assetFee
        );

    /**
     * @notice For a given price and fee, it returns the total amount a buyer must provide to cover for both
     * @param _price the target price
     * @param _buyerFeePermille the fee taken from the buyer, expressed in *1000 (ej: 10% = 0.1 => 100)
     * @return amount the buyer must sent to comply to this price and fees
     */
    function applyBuyerFee(uint256 _price, uint8 _buyerFeePermille) internal pure returns (uint256 amount) {
        if (_buyerFeePermille == 0) {
            amount = _price;
        } else {
            amount = _price.add(_price.mul(_buyerFeePermille).div(1000));
        }
    }

    /**
     * @dev Determines the minimum amount when increasing an existing offer or bid.
     */
    function _getMinIncrement(uint256 currentAmount) internal view returns (uint256) {
        uint256 minIncrement = currentAmount.mul(minIncrementPermille).div(1000);
        if (minIncrement == 0) {
            // Since minIncrement reduces from the currentAmount, this cannot overflow.
            // The next amount must be at least 1 wei greater than the current.
            return currentAmount + 1;
        }

        return minIncrement + currentAmount;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[1000] private __gap;
}

File 51 of 79 : SendValueWithFallbackWithdraw.sol
// SPDX-License-Identifier: MIT OR Apache-2.0

/// @dev Taken from https://github.com/f8n/fnd-protocol/tree/v2.0.3

import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";

pragma solidity ^0.7.6;

/**
 * @title A mixin for sending ETH with a fallback withdraw mechanism.
 * @notice Attempt to send ETH and if the transfer fails or runs out of gas, store the balance
 * in the pendingWithdrawals for future withdrawal instead.
 */
abstract contract SendValueWithFallbackWithdraw is OwnableUpgradeable {
    /// @dev Tracks the amount of ETH that is stored in escrow for future withdrawal.
    mapping(address => uint256) internal pendingWithdrawals;

    /**
     * @notice Emitted when escrowed funds are withdrawn.
     * @param executor The account which has withdrawn ETH, either the owner or an Admin.
     * @param owner The owner whose ETH has been withdrawn from.
     * @param recipient The address where the funds were transfered to.
     * @param amount The amount of ETH which has been withdrawn.
     */
    event PendingWithdrawalCompleted(
        address indexed executor,
        address indexed owner,
        address recipient,
        uint256 amount
    );

    /**
     * @notice Emitted when escrowed funds are deposite into pending Withdrawals.
     * @param owner The owner whose ETH has been deposit.
     * @param amount The amount of ETH which has been deposit.
     */
    event PendingWithdrawalDeposit(address indexed owner, uint256 amount);

    /**
     * @dev Attempt to send a user or contract ETH and
     * if it fails store the amount owned for later withdrawal .
     *  @dev This function doesn't check for reentrancy issues so be careful when invoking
     */
    function _sendValueWithFallbackWithdraw(
        address payable user,
        uint256 amount,
        uint256 gasLimit
    ) internal {
        if (amount == 0) {
            return;
        }
        // Cap the gas to prevent consuming all available gas to block a tx from completing successfully
        // solhint-disable-next-line avoid-low-level-calls
        (bool success, ) = user.call{ value: amount, gas: gasLimit }("");
        if (!success) {
            // Store the funds that failed to send for the user pendingWithdrawals list
            pendingWithdrawals[user] += amount;
            emit PendingWithdrawalDeposit(user, amount);
        }
    }

    function _withdrawTo(address from, address payable recipient) internal {
        uint256 pendingAmount = pendingWithdrawals[from];
        if (pendingAmount != 0) {
            // No reentray is possible
            pendingWithdrawals[from] = 0;
            (bool success, ) = recipient.call{ value: pendingAmount }("");
            require(success, "withdrawal failed");
            emit PendingWithdrawalCompleted(msg.sender, from, recipient, pendingAmount);
        }
    }

    /**
     * @notice Allows owner to widthawl pending funds (on failed sale send).
     * @param recipient The address to sent the locked funds to.
     */
    function withdrawTo(address payable recipient) public {
        _withdrawTo(msg.sender, recipient);
    }

    /**
     * @notice Allows Enigma to widthawl pending funds (on failed sale send) on behalf of a user.
     * This should only be used for extreme cases when the user has prove unintended funds locked up.
     * @param fundsOwner The user address holding the pending funds.
     * @param recipient The address to sent the locked funds to.
     */
    function adminWithdrawTo(address fundsOwner, address payable recipient) external onlyOwner {
        _withdrawTo(fundsOwner, recipient);
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[500] private __gap;
}

File 52 of 79 : ERC721Upgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../../utils/ContextUpgradeable.sol";
import "./IERC721Upgradeable.sol";
import "./IERC721MetadataUpgradeable.sol";
import "./IERC721EnumerableUpgradeable.sol";
import "./IERC721ReceiverUpgradeable.sol";
import "../../introspection/ERC165Upgradeable.sol";
import "../../math/SafeMathUpgradeable.sol";
import "../../utils/AddressUpgradeable.sol";
import "../../utils/EnumerableSetUpgradeable.sol";
import "../../utils/EnumerableMapUpgradeable.sol";
import "../../utils/StringsUpgradeable.sol";
import "../../proxy/Initializable.sol";

/**
 * @title ERC721 Non-Fungible Token Standard basic implementation
 * @dev see https://eips.ethereum.org/EIPS/eip-721
 */
contract ERC721Upgradeable is Initializable, ContextUpgradeable, ERC165Upgradeable, IERC721Upgradeable, IERC721MetadataUpgradeable, IERC721EnumerableUpgradeable {
    using SafeMathUpgradeable for uint256;
    using AddressUpgradeable for address;
    using EnumerableSetUpgradeable for EnumerableSetUpgradeable.UintSet;
    using EnumerableMapUpgradeable for EnumerableMapUpgradeable.UintToAddressMap;
    using StringsUpgradeable for uint256;

    // Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
    // which can be also obtained as `IERC721Receiver(0).onERC721Received.selector`
    bytes4 private constant _ERC721_RECEIVED = 0x150b7a02;

    // Mapping from holder address to their (enumerable) set of owned tokens
    mapping (address => EnumerableSetUpgradeable.UintSet) private _holderTokens;

    // Enumerable mapping from token ids to their owners
    EnumerableMapUpgradeable.UintToAddressMap private _tokenOwners;

    // Mapping from token ID to approved address
    mapping (uint256 => address) private _tokenApprovals;

    // Mapping from owner to operator approvals
    mapping (address => mapping (address => bool)) private _operatorApprovals;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Optional mapping for token URIs
    mapping (uint256 => string) private _tokenURIs;

    // Base URI
    string private _baseURI;

    /*
     *     bytes4(keccak256('balanceOf(address)')) == 0x70a08231
     *     bytes4(keccak256('ownerOf(uint256)')) == 0x6352211e
     *     bytes4(keccak256('approve(address,uint256)')) == 0x095ea7b3
     *     bytes4(keccak256('getApproved(uint256)')) == 0x081812fc
     *     bytes4(keccak256('setApprovalForAll(address,bool)')) == 0xa22cb465
     *     bytes4(keccak256('isApprovedForAll(address,address)')) == 0xe985e9c5
     *     bytes4(keccak256('transferFrom(address,address,uint256)')) == 0x23b872dd
     *     bytes4(keccak256('safeTransferFrom(address,address,uint256)')) == 0x42842e0e
     *     bytes4(keccak256('safeTransferFrom(address,address,uint256,bytes)')) == 0xb88d4fde
     *
     *     => 0x70a08231 ^ 0x6352211e ^ 0x095ea7b3 ^ 0x081812fc ^
     *        0xa22cb465 ^ 0xe985e9c5 ^ 0x23b872dd ^ 0x42842e0e ^ 0xb88d4fde == 0x80ac58cd
     */
    bytes4 private constant _INTERFACE_ID_ERC721 = 0x80ac58cd;

    /*
     *     bytes4(keccak256('name()')) == 0x06fdde03
     *     bytes4(keccak256('symbol()')) == 0x95d89b41
     *     bytes4(keccak256('tokenURI(uint256)')) == 0xc87b56dd
     *
     *     => 0x06fdde03 ^ 0x95d89b41 ^ 0xc87b56dd == 0x5b5e139f
     */
    bytes4 private constant _INTERFACE_ID_ERC721_METADATA = 0x5b5e139f;

    /*
     *     bytes4(keccak256('totalSupply()')) == 0x18160ddd
     *     bytes4(keccak256('tokenOfOwnerByIndex(address,uint256)')) == 0x2f745c59
     *     bytes4(keccak256('tokenByIndex(uint256)')) == 0x4f6ccce7
     *
     *     => 0x18160ddd ^ 0x2f745c59 ^ 0x4f6ccce7 == 0x780e9d63
     */
    bytes4 private constant _INTERFACE_ID_ERC721_ENUMERABLE = 0x780e9d63;

    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    function __ERC721_init(string memory name_, string memory symbol_) internal initializer {
        __Context_init_unchained();
        __ERC165_init_unchained();
        __ERC721_init_unchained(name_, symbol_);
    }

    function __ERC721_init_unchained(string memory name_, string memory symbol_) internal initializer {
        _name = name_;
        _symbol = symbol_;

        // register the supported interfaces to conform to ERC721 via ERC165
        _registerInterface(_INTERFACE_ID_ERC721);
        _registerInterface(_INTERFACE_ID_ERC721_METADATA);
        _registerInterface(_INTERFACE_ID_ERC721_ENUMERABLE);
    }

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: balance query for the zero address");
        return _holderTokens[owner].length();
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        return _tokenOwners.get(tokenId, "ERC721: owner query for nonexistent token");
    }

    /**
     * @dev See {IERC721Metadata-name}.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev See {IERC721Metadata-symbol}.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");

        string memory _tokenURI = _tokenURIs[tokenId];
        string memory base = baseURI();

        // If there is no base URI, return the token URI.
        if (bytes(base).length == 0) {
            return _tokenURI;
        }
        // If both are set, concatenate the baseURI and tokenURI (via abi.encodePacked).
        if (bytes(_tokenURI).length > 0) {
            return string(abi.encodePacked(base, _tokenURI));
        }
        // If there is a baseURI but no tokenURI, concatenate the tokenID to the baseURI.
        return string(abi.encodePacked(base, tokenId.toString()));
    }

    /**
    * @dev Returns the base URI set via {_setBaseURI}. This will be
    * automatically added as a prefix in {tokenURI} to each token's URI, or
    * to the token ID if no specific URI is set for that token ID.
    */
    function baseURI() public view virtual returns (string memory) {
        return _baseURI;
    }

    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
        return _holderTokens[owner].at(index);
    }

    /**
     * @dev See {IERC721Enumerable-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        // _tokenOwners are indexed by tokenIds, so .length() returns the number of tokenIds
        return _tokenOwners.length();
    }

    /**
     * @dev See {IERC721Enumerable-tokenByIndex}.
     */
    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
        (uint256 tokenId, ) = _tokenOwners.at(index);
        return tokenId;
    }

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721Upgradeable.ownerOf(tokenId);
        require(to != owner, "ERC721: approval to current owner");

        require(_msgSender() == owner || ERC721Upgradeable.isApprovedForAll(owner, _msgSender()),
            "ERC721: approve caller is not owner nor approved for all"
        );

        _approve(to, tokenId);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), "ERC721: approved query for nonexistent token");

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        require(operator != _msgSender(), "ERC721: approve to caller");

        _operatorApprovals[_msgSender()][operator] = approved;
        emit ApprovalForAll(_msgSender(), operator, approved);
    }

    /**
     * @dev See {IERC721-isApprovedForAll}.
     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(address from, address to, uint256 tokenId) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");

        _transfer(from, to, tokenId);
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory _data) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        _safeTransfer(from, to, tokenId, _data);
    }

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * `_data` is additional data, it has no specified format and it is sent in call to `to`.
     *
     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
     * implement alternative mechanisms to perform token transfer, such as signature-based.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeTransfer(address from, address to, uint256 tokenId, bytes memory _data) internal virtual {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted (`_mint`),
     * and stop existing when they are burned (`_burn`).
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _tokenOwners.contains(tokenId);
    }

    /**
     * @dev Returns whether `spender` is allowed to manage `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        require(_exists(tokenId), "ERC721: operator query for nonexistent token");
        address owner = ERC721Upgradeable.ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || ERC721Upgradeable.isApprovedForAll(owner, spender));
    }

    /**
     * @dev Safely mints `tokenId` and transfers it to `to`.
     *
     * Requirements:
     d*
     * - `tokenId` must not exist.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(address to, uint256 tokenId) internal virtual {
        _safeMint(to, tokenId, "");
    }

    /**
     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
     */
    function _safeMint(address to, uint256 tokenId, bytes memory _data) internal virtual {
        _mint(to, tokenId);
        require(_checkOnERC721Received(address(0), to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    /**
     * @dev Mints `tokenId` and transfers it to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - `to` cannot be the zero address.
     *
     * Emits a {Transfer} event.
     */
    function _mint(address to, uint256 tokenId) internal virtual {
        require(to != address(0), "ERC721: mint to the zero address");
        require(!_exists(tokenId), "ERC721: token already minted");

        _beforeTokenTransfer(address(0), to, tokenId);

        _holderTokens[to].add(tokenId);

        _tokenOwners.set(tokenId, to);

        emit Transfer(address(0), to, tokenId);
    }

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721Upgradeable.ownerOf(tokenId); // internal owner

        _beforeTokenTransfer(owner, address(0), tokenId);

        // Clear approvals
        _approve(address(0), tokenId);

        // Clear metadata (if any)
        if (bytes(_tokenURIs[tokenId]).length != 0) {
            delete _tokenURIs[tokenId];
        }

        _holderTokens[owner].remove(tokenId);

        _tokenOwners.remove(tokenId);

        emit Transfer(owner, address(0), tokenId);
    }

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    function _transfer(address from, address to, uint256 tokenId) internal virtual {
        require(ERC721Upgradeable.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own"); // internal owner
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId);

        // Clear approvals from the previous owner
        _approve(address(0), tokenId);

        _holderTokens[from].remove(tokenId);
        _holderTokens[to].add(tokenId);

        _tokenOwners.set(tokenId, to);

        emit Transfer(from, to, tokenId);
    }

    /**
     * @dev Sets `_tokenURI` as the tokenURI of `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _setTokenURI(uint256 tokenId, string memory _tokenURI) internal virtual {
        require(_exists(tokenId), "ERC721Metadata: URI set of nonexistent token");
        _tokenURIs[tokenId] = _tokenURI;
    }

    /**
     * @dev Internal function to set the base URI for all token IDs. It is
     * automatically added as a prefix to the value returned in {tokenURI},
     * or to the token ID if {tokenURI} is empty.
     */
    function _setBaseURI(string memory baseURI_) internal virtual {
        _baseURI = baseURI_;
    }

    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
     * The call is not executed if the target address is not a contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param _data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkOnERC721Received(address from, address to, uint256 tokenId, bytes memory _data)
        private returns (bool)
    {
        if (!to.isContract()) {
            return true;
        }
        bytes memory returndata = to.functionCall(abi.encodeWithSelector(
            IERC721ReceiverUpgradeable(to).onERC721Received.selector,
            _msgSender(),
            from,
            tokenId,
            _data
        ), "ERC721: transfer to non ERC721Receiver implementer");
        bytes4 retval = abi.decode(returndata, (bytes4));
        return (retval == _ERC721_RECEIVED);
    }

    function _approve(address to, uint256 tokenId) private {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721Upgradeable.ownerOf(tokenId), to, tokenId); // internal owner
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal virtual { }
    uint256[41] private __gap;
}

File 53 of 79 : IERC721MetadataUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

import "./IERC721Upgradeable.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721MetadataUpgradeable is IERC721Upgradeable {

    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}

File 54 of 79 : IERC721EnumerableUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

import "./IERC721Upgradeable.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721EnumerableUpgradeable is IERC721Upgradeable {

    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}

File 55 of 79 : IERC721ReceiverUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721ReceiverUpgradeable {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(address operator, address from, uint256 tokenId, bytes calldata data) external returns (bytes4);
}

File 56 of 79 : EnumerableSetUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 */
library EnumerableSetUpgradeable {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;

        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping (bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) { // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

            bytes32 lastvalue = set._values[lastIndex];

            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastvalue;
            // Update the index for the moved value
            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        require(set._values.length > index, "EnumerableSet: index out of bounds");
        return set._values[index];
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }


    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
}

File 57 of 79 : ERC721HolderUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./IERC721ReceiverUpgradeable.sol";
import "../../proxy/Initializable.sol";

  /**
   * @dev Implementation of the {IERC721Receiver} interface.
   *
   * Accepts all token transfers. 
   * Make sure the contract is able to use its token with {IERC721-safeTransferFrom}, {IERC721-approve} or {IERC721-setApprovalForAll}.
   */
contract ERC721HolderUpgradeable is Initializable, IERC721ReceiverUpgradeable {
    function __ERC721Holder_init() internal initializer {
        __ERC721Holder_init_unchained();
    }

    function __ERC721Holder_init_unchained() internal initializer {
    }

    /**
     * @dev See {IERC721Receiver-onERC721Received}.
     *
     * Always returns `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(address, address, uint256, bytes memory) public virtual override returns (bytes4) {
        return this.onERC721Received.selector;
    }
    uint256[50] private __gap;
}

File 58 of 79 : EnigmaMarket.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC721/ERC721HolderUpgradeable.sol";
import "../interfaces/ITransferProxy.sol";
import "./NFTMarketReserveAuction.sol";
import "./TradeV4.sol";

/// @title EnigmaMarket
///
/// @dev This contract is a Transparent Upgradable based in openZeppelin v3.4.0.
///         Be careful when upgrade, you must respect the same storage.

contract EnigmaMarket is
    TradeV4,
    ERC721HolderUpgradeable, // Make sure the contract is able to use its
    NFTMarketReserveAuction
{
    /// oz-upgrades-unsafe-allow constructor
    // solhint-disable-next-line
    constructor() initializer {}

    /**
     * @notice Called once to configure the contract after the initial proxy deployment.
     * @dev This farms the initialize call out to inherited contracts as needed to initialize mutable variables.
     * @param _buyerFee the fee taken from the buyer, expressed in *1000 (ej: 10% = 0.1 => 100)
     * @param _sellerFee the fee taken from the seller, expressed in *1000 (ej: 10% = 0.1 => 100)
     * @param _transferProxy the proxy from wich all NFT transfers are gonna be processed from.
     * @param _enigmaNFT721Address Enigma ERC721 NFT proxy.
     * @param _enigmaNFT1155Address Enigma ERC1155 NFT proxy.
     * @param _custodialAddress The address on wich NFTs are gonna be kept during Fiat Trades.
     * @param _minDuration The min duration for auctions, in seconds.
     * @param _maxDuration The max duration for auctions, in seconds.
     * @param _minIncrementPermille The minimum required when making an offer or placing a bid. Ej: 100 => 0.1 => 10%
     */
    function fullInitialize(
        uint8 _buyerFee,
        uint8 _sellerFee,
        ITransferProxy _transferProxy,
        address _enigmaNFT721Address,
        address _enigmaNFT1155Address,
        address _custodialAddress,
        uint256 _minDuration,
        uint256 _maxDuration,
        uint16 _minIncrementPermille
    ) external initializer {
        initializeTradeV4(
            _buyerFee,
            _sellerFee,
            _transferProxy,
            _enigmaNFT721Address,
            _enigmaNFT1155Address,
            _custodialAddress
        );
        __Ownable_init();
        __ReentrancyGuard_init();
        _initializeNFTMarketAuction();
        _initializeNFTMarketReserveAuction(_minDuration, _maxDuration);
        _initializeNFTMarketCore(_minIncrementPermille);
    }

    /**
     * @notice Called once to configure the contract after the initial proxy deployment.
     * @dev as we are updating an already deployed contracts, legacy vars don't need init.
     * @param _minDuration The min duration for auctions, in seconds.
     * @param _maxDuration The max duration for auctions, in seconds.
     */
    function upgradeInitialize(uint256 _minDuration, uint256 _maxDuration) external onlyOwner {
        _initializeNFTMarketAuction();
        _initializeNFTMarketReserveAuction(_minDuration, _maxDuration);
    }

    function getPlatformTreasury() public view returns (address payable) {
        // TODO: review if we don't need a new field for collecting fees
        return payable(owner());
    }

    /**
     * @inheritdoc NFTMarketCore
     */
    function _transferFromEscrow(
        address nftContract,
        uint256 tokenId,
        address recipient
    ) internal virtual override {
        // As we are transfering through our own market, there's no need to go by transferProxy
        IERC721(nftContract).transferFrom(address(this), recipient, tokenId);
    }

    /**
     * @inheritdoc NFTMarketCore
     */
    function _transferToEscrow(address nftContract, uint256 tokenId) internal virtual override {
        safeTransferFrom(AssetType.ERC721, msg.sender, address(this), nftContract, tokenId, 1);
    }

    /**
     * @dev Be careful when invoking this function as reentrancy guard should be put in place
     */
    // slither-disable-next-line reentrancy-eth
    function _distFunds(
        address nftContract,
        uint256 tokenId,
        uint256 amount,
        address payable seller
    )
        internal
        override
        returns (
            uint256 platformFee,
            uint256 royaltyFee,
            uint256 assetFee
        )
    {
        // Disable slither warning because it's only invoked from functions with nonReentrant checks
        Fee memory fee = getFees(amount, nftContract, tokenId);
        _sendValueWithFallbackWithdraw(getPlatformTreasury(), fee.platformFee, SEND_VALUE_GAS_LIMIT_SINGLE_RECIPIENT);
        uint256 toSeller;
        // Verifies it the seller is the creator, to avoid doble sent and save some gas
        if (seller == fee.tokenCreator) {
            toSeller = fee.royaltyFee + fee.assetFee;
        } else {
            _sendValueWithFallbackWithdraw(
                payable(fee.tokenCreator),
                fee.royaltyFee,
                SEND_VALUE_GAS_LIMIT_SINGLE_RECIPIENT
            );
            toSeller = fee.assetFee;
        }
        _sendValueWithFallbackWithdraw(seller, toSeller, SEND_VALUE_GAS_LIMIT_SINGLE_RECIPIENT);
        return (fee.platformFee, fee.royaltyFee, fee.assetFee);
    }

    /*********************
     ** PUBLIC FUNCTIONS *
     *********************/

    /**
     * @notice Creates an auction for the given NFT.
     * The NFT is held in escrow until the auction is finalized or canceled.
     * @param nftContract The address of the NFT contract.
     * @param tokenId The id of the NFT.
     * @param duration seconds for how long an auction lasts for once the first bid has been received.
     * @param reservePrice The initial reserve price for the auction.
     */
    function createReserveAuction(
        address nftContract,
        uint256 tokenId,
        uint256 duration,
        uint256 reservePrice
    ) external nonReentrant onlyValidAuctionConfig(reservePrice) {
        // get the amount, including buyer fee for this reserve price
        uint256 amount = applyBuyerFee(reservePrice, buyerFeePermille);
        createReserveAuctionFor(
            nftContract,
            tokenId,
            duration,
            reservePrice,
            amount,
            buyerFeePermille,
            sellerFeePermille
        );
    }
}

File 59 of 79 : TestTradeV4.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "../market/EnigmaMarket.sol";

/// @title TestTradeV4
///
/// @dev This contract extends from Trade Series for upgradeablity testing

contract TestTradeV4 is TradeV4 {
    function initialize(
        uint8 _buyerFee,
        uint8 _sellerFee,
        ITransferProxy _transferProxy,
        address _enigmaNFT721Address,
        address _enigmaNFT1155Address,
        address _custodialAddress
    ) external initializer {
        initializeTradeV4(
            _buyerFee,
            _sellerFee,
            _transferProxy,
            _enigmaNFT721Address,
            _enigmaNFT1155Address,
            _custodialAddress
        );
    }
}

File 60 of 79 : TestEnigmaMarket.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "../market/EnigmaMarket.sol";
import "../ERC721/EnigmaNFT721.sol";

/// @title TestEnigmaMarket
///
/// @dev This contract extends from Trade Series for upgradeablity testing

contract TestEnigmaMarket is EnigmaMarket {
    uint256 public aNewValue;

    /// @dev trivial getter override, to verify actual change
    function sellerServiceFee() external view virtual override returns (uint8) {
        return 42;
    }

    /// @dev makes internal storage visible
    function getMaxDuration() external view returns (uint256) {
        return maxDuration;
    }

    /// @dev makes internal storage visible
    function getMinDuration() external view returns (uint256) {
        return minDuration;
    }
}

contract TestAuctionSeller {
    bool public doFail;

    function doApprove(
        address enigmaNFT721,
        address transferProxy,
        uint256 tokenId
    ) public {
        EnigmaNFT721(enigmaNFT721).approve(transferProxy, tokenId);
    }

    function doCreateReserveAuction(
        address market,
        address nftContract,
        uint256 tokenId,
        uint256 duration,
        uint256 reservePrice
    ) public {
        doFail = true;
        TestEnigmaMarket(market).createReserveAuction(nftContract, tokenId, duration, reservePrice);
    }

    function doWithdrawTo(address market, address payable user) public {
        doFail = false;
        TestEnigmaMarket(market).withdrawTo(user);
    }

    function setDoFail(bool _doFail) public {
        doFail = _doFail;
    }

    /// receive fails on purpose to test this scenario
    receive() external payable {
        if (doFail) revert("test only");
    }
}

File 61 of 79 : EnigmaNFT721.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "./BaseEnigmaNFT721.sol";

/// @title EnigmaNFT721
///
/// @dev This contract extends from BaseEnigmaNFT721

contract EnigmaNFT721 is BaseEnigmaNFT721 {
    struct Sign {
        uint8 v;
        bytes32 r;
        bytes32 s;
    }

    /// oz-upgrades-unsafe-allow constructor
    // solhint-disable-next-line
    constructor() initializer {}

    /**
     * @notice Internal function to verify a sign to mint tokens
     * Reverts if the sign verification fails.
     * @param tokenURI_ string memory URI of the token to be minted.
     * @param sign_ struct combination of uint8, bytes32, bytes32 are v, r, s.
     */
    function verifySign(string memory tokenURI_, Sign memory sign_) internal view {
        bytes32 hash = keccak256(abi.encodePacked(this, tokenURI_));
        require(
            owner() ==
                ecrecover(
                    keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash)),
                    sign_.v,
                    sign_.r,
                    sign_.s
                ),
            "Owner sign verification failed"
        );
    }

    /**
     * @notice public function to mint a new token.
     * @param tokenURI_ string memory URI of the token to be minted.
     * @param fee_ uint256 royalty of the token to be minted.
     * @param sign_ struct combination of uint8, bytes32, bytes32 are v, r, s.
     */
    function createCollectible(
        string memory tokenURI_,
        uint256 fee_,
        Sign memory sign_
    ) external returns (uint256) {
        uint256 newItemId = tokenCounter;
        verifySign(tokenURI_, sign_);
        tokenCounter = tokenCounter + 1;
        _safeMint(msg.sender, newItemId, fee_);
        _setTokenURI(newItemId, tokenURI_);
        return newItemId;
    }
}

File 62 of 79 : BaseEnigmaNFT721.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;

import "@openzeppelin/contracts-upgradeable/token/ERC721/ERC721BurnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";

import "../interfaces/ITransferGatekeeper.sol";
import "../interfaces/IRoyaltyAwareNFT.sol";

/// @title BaseEnigmaNFT721
///
/// @dev This contract is a ERC721 burnable and upgradable based in openZeppelin v3.4.0.
///         Be careful when upgrade, you must respect the same storage.

abstract contract BaseEnigmaNFT721 is IRoyaltyAwareNFT, ERC721BurnableUpgradeable, OwnableUpgradeable {
    /* Storage */
    //mapping for token royaltyFee
    mapping(uint256 => uint256) private _royaltyFee;

    //mapping for token creator
    mapping(uint256 => address) private _creator;

    //token id counter, increase by 1 for each new mint
    uint256 public tokenCounter;

    //Transfer Gatekeeper with logic to allow token transfers
    ITransferGatekeeper public transferGatekeeper;

    /* events */
    event URI(string value, uint256 indexed id);
    event TokenBaseURI(string value);

    /* functions */

    /**
     * @notice Initialize NFT721 contract.
     *
     * @param name_ the token name
     * @param symbol_ the token symbol
     * @param tokenURIPrefix_ the toke base uri
     */
    function initialize(
        string memory name_,
        string memory symbol_,
        string memory tokenURIPrefix_
    ) external initializer {
        __ERC721_init(name_, symbol_);
        __ERC721Burnable_init();
        __Ownable_init();

        tokenCounter = 1;
        _setBaseURI(tokenURIPrefix_);
    }

    /// oz-upgrades-unsafe-allow constructor
    // solhint-disable-next-line
    constructor() initializer {}

    /**
     * @notice get the royalty fee of a token
     *
     * @param tokenId the token id
     * @return the royalty fee seted to the token
     */
    function royaltyFee(uint256 tokenId) external view virtual override returns (uint256) {
        return _royaltyFee[tokenId];
    }

    /**
     * @notice Get the creator of given tokenID.
     * @param tokenId ID of the Token.
     * @return creator of given ID.
     */
    function getCreator(uint256 tokenId) external view virtual override returns (address) {
        return _creator[tokenId];
    }

    /**
     * @notice Internal function to set the base URI for all token IDs. It is
     * automatically added as a prefix to the value returned in {tokenURI},
     * or to the token ID if {tokenURI} is empty.
     * @param baseURI_ the new base uri
     */
    function _setBaseURI(string memory baseURI_) internal virtual override {
        super._setBaseURI(baseURI_);
        emit TokenBaseURI(baseURI_);
    }

    /**
     * @notice Internal function to set the token URI for a given token.
     * Reverts if the token ID does not exist.
     * @param tokenId uint256 ID of the token to set its URI
     * @param _tokenURI string URI to assign
     */
    function _setTokenURI(uint256 tokenId, string memory _tokenURI) internal virtual override {
        super._setTokenURI(tokenId, _tokenURI);
        emit URI(_tokenURI, tokenId);
    }

    /**
     * @notice call safe mint function and set token creator and royalty fee
     */
    function _safeMint(
        address to,
        uint256 tokenId,
        uint256 fee
    ) internal virtual {
        _creator[tokenId] = msg.sender;
        _royaltyFee[tokenId] = fee;
        super._safeMint(to, tokenId, "");
    }

    /**
     * @notice call transfer fucntion after check transferGatekeeper allowance
     */
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual override {
        bytes memory allData = abi.encode("721", tokenId);
        require(transferGatekeeper.canTransfer(from, to, _msgSender(), allData), "Transfer not approved");
        super._transfer(from, to, tokenId);
    }

    /**
     * @notice external function to set the base URI for all token IDs
     * @param baseURI_ the new base uri
     */
    function setBaseURI(string memory baseURI_) external onlyOwner {
        _setBaseURI(baseURI_);
    }

    /**
     * @notice Set a transferGatekeeper with the logic to allow transfer NFTs
     * @param _transferGatekeeper The transferGatekeeper contract address
     */
    function setTransferGatekeeper(ITransferGatekeeper _transferGatekeeper) external onlyOwner {
        transferGatekeeper = _transferGatekeeper;
    }
}

File 63 of 79 : ERC721BurnableUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../../utils/ContextUpgradeable.sol";
import "./ERC721Upgradeable.sol";
import "../../proxy/Initializable.sol";

/**
 * @title ERC721 Burnable Token
 * @dev ERC721 Token that can be irreversibly burned (destroyed).
 */
abstract contract ERC721BurnableUpgradeable is Initializable, ContextUpgradeable, ERC721Upgradeable {
    function __ERC721Burnable_init() internal initializer {
        __Context_init_unchained();
        __ERC165_init_unchained();
        __ERC721Burnable_init_unchained();
    }

    function __ERC721Burnable_init_unchained() internal initializer {
    }
    /**
     * @dev Burns `tokenId`. See {ERC721-_burn}.
     *
     * Requirements:
     *
     * - The caller must own `tokenId` or be an approved operator.
     */
    function burn(uint256 tokenId) public virtual {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721Burnable: caller is not owner nor approved");
        _burn(tokenId);
    }
    uint256[50] private __gap;
}

File 64 of 79 : TestEnigmaNFT721.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "../ERC721/BaseEnigmaNFT721.sol";

/// @title TestEnigmaNFT721
///
/// @dev This contract extends from BaseEnigmaNFT721 for upgradeablity testing

contract TestEnigmaNFT721 is BaseEnigmaNFT721 {
    event CollectibleCreated(uint256 tokenId);

    /**
     * @notice public function to mint a new token.
     * @param tokenURI_ string memory URI of the token to be minted.
     * @param fee_ uint256 royalty of the token to be minted.
     */
    function createCollectible(string memory tokenURI_, uint256 fee_) external returns (uint256) {
        uint256 newItemId = tokenCounter;
        tokenCounter = tokenCounter + 1;
        emit CollectibleCreated(newItemId);
        _safeMint(msg.sender, newItemId, fee_);
        _setTokenURI(newItemId, tokenURI_);
        return newItemId;
    }
}

File 65 of 79 : EnigmaUserToken721.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "./BaseEnigmaNFT721.sol";

/// @title EnigmaUserToken721
///
/// @dev This contract extends from BaseEnigmaNFT721

contract EnigmaUserToken721 is BaseEnigmaNFT721 {
    /// oz-upgrades-unsafe-allow constructor
    // solhint-disable-next-line
    constructor() initializer {}

    /**
     * @notice public function to mint a new token.
     * @param tokenURI_ string memory URI of the token to be minted.
     * @param fee_ uint256 royalty of the token to be minted.
     */
    function createCollectible(string memory tokenURI_, uint256 fee_) external returns (uint256) {
        uint256 newItemId = tokenCounter;
        tokenCounter = tokenCounter + 1;
        _safeMint(msg.sender, newItemId, fee_);
        _setTokenURI(newItemId, tokenURI_);
        return newItemId;
    }
}

File 66 of 79 : TestTransferGatekepper.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "../interfaces/ITransferGatekeeper.sol";

/// @title TestTransferGatekeeper

contract TestTransferGatekeeper is ITransferGatekeeper {
    string public encodeType;
    bytes public data;
    uint256[2] public tokenIds;
    uint256[2] public amounts;

    function canTransfer(
        address,
        address,
        address,
        bytes memory encodedData
    ) external view override returns (bool) {
        if (bytes(encodeType).length != 0) {
            string memory _encodeType = abi.decode(encodedData, (string));
            if (keccak256(bytes(_encodeType)) == keccak256(bytes("721"))) {
                (, uint256 _tokenId) = abi.decode(encodedData, (string, uint256));
                return tokenIds[0] == _tokenId;
            }
            if (keccak256(bytes(_encodeType)) == keccak256(bytes("1155"))) {
                (, uint256 _tokenId, uint256 _amount, bytes memory _data) =
                    abi.decode(encodedData, (string, uint256, uint256, bytes));
                return (tokenIds[0] == _tokenId &&
                    amounts[0] == _amount &&
                    keccak256(bytes(data)) == keccak256(bytes(_data)));
            }
            if (keccak256(bytes(_encodeType)) == keccak256(bytes("1155_batch"))) {
                (, uint256[] memory _tokenIds, uint256[] memory _amounts, bytes memory _data) =
                    abi.decode(encodedData, (string, uint256[], uint256[], bytes));
                return (tokenIds[0] == _tokenIds[0] &&
                    tokenIds[1] == _tokenIds[1] &&
                    amounts[0] == _amounts[0] &&
                    amounts[1] == _amounts[1] &&
                    keccak256(bytes(data)) == keccak256(bytes(_data)));
            }
        }
        return false;
    }

    function set721Data(uint256 _tokenId) public {
        encodeType = "721";
        tokenIds[0] = _tokenId;
    }

    function set1155Data(
        uint256 _tokenId,
        uint256 _amount,
        bytes memory _data
    ) public {
        encodeType = "1155";
        tokenIds[0] = _tokenId;
        amounts[0] = _amount;
        data = _data;
    }

    function set1155BatchData(
        uint256 _tokenId,
        uint256 _amount,
        bytes memory _data
    ) public {
        encodeType = "1155_batch";
        tokenIds[1] = _tokenId;
        amounts[1] = _amount;
        data = _data;
    }
}

File 67 of 79 : ERC1155.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./IERC1155.sol";
import "./IERC1155MetadataURI.sol";
import "./IERC1155Receiver.sol";
import "../../utils/Context.sol";
import "../../introspection/ERC165.sol";
import "../../math/SafeMath.sol";
import "../../utils/Address.sol";

/**
 *
 * @dev Implementation of the basic standard multi-token.
 * See https://eips.ethereum.org/EIPS/eip-1155
 * Originally based on code by Enjin: https://github.com/enjin/erc-1155
 *
 * _Available since v3.1._
 */
contract ERC1155 is Context, ERC165, IERC1155, IERC1155MetadataURI {
    using SafeMath for uint256;
    using Address for address;

    // Mapping from token ID to account balances
    mapping (uint256 => mapping(address => uint256)) private _balances;

    // Mapping from account to operator approvals
    mapping (address => mapping(address => bool)) private _operatorApprovals;

    // Used as the URI for all token types by relying on ID substitution, e.g. https://token-cdn-domain/{id}.json
    string private _uri;

    /*
     *     bytes4(keccak256('balanceOf(address,uint256)')) == 0x00fdd58e
     *     bytes4(keccak256('balanceOfBatch(address[],uint256[])')) == 0x4e1273f4
     *     bytes4(keccak256('setApprovalForAll(address,bool)')) == 0xa22cb465
     *     bytes4(keccak256('isApprovedForAll(address,address)')) == 0xe985e9c5
     *     bytes4(keccak256('safeTransferFrom(address,address,uint256,uint256,bytes)')) == 0xf242432a
     *     bytes4(keccak256('safeBatchTransferFrom(address,address,uint256[],uint256[],bytes)')) == 0x2eb2c2d6
     *
     *     => 0x00fdd58e ^ 0x4e1273f4 ^ 0xa22cb465 ^
     *        0xe985e9c5 ^ 0xf242432a ^ 0x2eb2c2d6 == 0xd9b67a26
     */
    bytes4 private constant _INTERFACE_ID_ERC1155 = 0xd9b67a26;

    /*
     *     bytes4(keccak256('uri(uint256)')) == 0x0e89341c
     */
    bytes4 private constant _INTERFACE_ID_ERC1155_METADATA_URI = 0x0e89341c;

    /**
     * @dev See {_setURI}.
     */
    constructor (string memory uri_) public {
        _setURI(uri_);

        // register the supported interfaces to conform to ERC1155 via ERC165
        _registerInterface(_INTERFACE_ID_ERC1155);

        // register the supported interfaces to conform to ERC1155MetadataURI via ERC165
        _registerInterface(_INTERFACE_ID_ERC1155_METADATA_URI);
    }

    /**
     * @dev See {IERC1155MetadataURI-uri}.
     *
     * This implementation returns the same URI for *all* token types. It relies
     * on the token type ID substitution mechanism
     * https://eips.ethereum.org/EIPS/eip-1155#metadata[defined in the EIP].
     *
     * Clients calling this function must replace the `\{id\}` substring with the
     * actual token type ID.
     */
    function uri(uint256) external view virtual override returns (string memory) {
        return _uri;
    }

    /**
     * @dev See {IERC1155-balanceOf}.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function balanceOf(address account, uint256 id) public view virtual override returns (uint256) {
        require(account != address(0), "ERC1155: balance query for the zero address");
        return _balances[id][account];
    }

    /**
     * @dev See {IERC1155-balanceOfBatch}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(
        address[] memory accounts,
        uint256[] memory ids
    )
        public
        view
        virtual
        override
        returns (uint256[] memory)
    {
        require(accounts.length == ids.length, "ERC1155: accounts and ids length mismatch");

        uint256[] memory batchBalances = new uint256[](accounts.length);

        for (uint256 i = 0; i < accounts.length; ++i) {
            batchBalances[i] = balanceOf(accounts[i], ids[i]);
        }

        return batchBalances;
    }

    /**
     * @dev See {IERC1155-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        require(_msgSender() != operator, "ERC1155: setting approval status for self");

        _operatorApprovals[_msgSender()][operator] = approved;
        emit ApprovalForAll(_msgSender(), operator, approved);
    }

    /**
     * @dev See {IERC1155-isApprovedForAll}.
     */
    function isApprovedForAll(address account, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[account][operator];
    }

    /**
     * @dev See {IERC1155-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes memory data
    )
        public
        virtual
        override
    {
        require(to != address(0), "ERC1155: transfer to the zero address");
        require(
            from == _msgSender() || isApprovedForAll(from, _msgSender()),
            "ERC1155: caller is not owner nor approved"
        );

        address operator = _msgSender();

        _beforeTokenTransfer(operator, from, to, _asSingletonArray(id), _asSingletonArray(amount), data);

        _balances[id][from] = _balances[id][from].sub(amount, "ERC1155: insufficient balance for transfer");
        _balances[id][to] = _balances[id][to].add(amount);

        emit TransferSingle(operator, from, to, id, amount);

        _doSafeTransferAcceptanceCheck(operator, from, to, id, amount, data);
    }

    /**
     * @dev See {IERC1155-safeBatchTransferFrom}.
     */
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    )
        public
        virtual
        override
    {
        require(ids.length == amounts.length, "ERC1155: ids and amounts length mismatch");
        require(to != address(0), "ERC1155: transfer to the zero address");
        require(
            from == _msgSender() || isApprovedForAll(from, _msgSender()),
            "ERC1155: transfer caller is not owner nor approved"
        );

        address operator = _msgSender();

        _beforeTokenTransfer(operator, from, to, ids, amounts, data);

        for (uint256 i = 0; i < ids.length; ++i) {
            uint256 id = ids[i];
            uint256 amount = amounts[i];

            _balances[id][from] = _balances[id][from].sub(
                amount,
                "ERC1155: insufficient balance for transfer"
            );
            _balances[id][to] = _balances[id][to].add(amount);
        }

        emit TransferBatch(operator, from, to, ids, amounts);

        _doSafeBatchTransferAcceptanceCheck(operator, from, to, ids, amounts, data);
    }

    /**
     * @dev Sets a new URI for all token types, by relying on the token type ID
     * substitution mechanism
     * https://eips.ethereum.org/EIPS/eip-1155#metadata[defined in the EIP].
     *
     * By this mechanism, any occurrence of the `\{id\}` substring in either the
     * URI or any of the amounts in the JSON file at said URI will be replaced by
     * clients with the token type ID.
     *
     * For example, the `https://token-cdn-domain/\{id\}.json` URI would be
     * interpreted by clients as
     * `https://token-cdn-domain/000000000000000000000000000000000000000000000000000000000004cce0.json`
     * for token type ID 0x4cce0.
     *
     * See {uri}.
     *
     * Because these URIs cannot be meaningfully represented by the {URI} event,
     * this function emits no events.
     */
    function _setURI(string memory newuri) internal virtual {
        _uri = newuri;
    }

    /**
     * @dev Creates `amount` tokens of token type `id`, and assigns them to `account`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - If `account` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function _mint(address account, uint256 id, uint256 amount, bytes memory data) internal virtual {
        require(account != address(0), "ERC1155: mint to the zero address");

        address operator = _msgSender();

        _beforeTokenTransfer(operator, address(0), account, _asSingletonArray(id), _asSingletonArray(amount), data);

        _balances[id][account] = _balances[id][account].add(amount);
        emit TransferSingle(operator, address(0), account, id, amount);

        _doSafeTransferAcceptanceCheck(operator, address(0), account, id, amount, data);
    }

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {_mint}.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function _mintBatch(address to, uint256[] memory ids, uint256[] memory amounts, bytes memory data) internal virtual {
        require(to != address(0), "ERC1155: mint to the zero address");
        require(ids.length == amounts.length, "ERC1155: ids and amounts length mismatch");

        address operator = _msgSender();

        _beforeTokenTransfer(operator, address(0), to, ids, amounts, data);

        for (uint i = 0; i < ids.length; i++) {
            _balances[ids[i]][to] = amounts[i].add(_balances[ids[i]][to]);
        }

        emit TransferBatch(operator, address(0), to, ids, amounts);

        _doSafeBatchTransferAcceptanceCheck(operator, address(0), to, ids, amounts, data);
    }

    /**
     * @dev Destroys `amount` tokens of token type `id` from `account`
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens of token type `id`.
     */
    function _burn(address account, uint256 id, uint256 amount) internal virtual {
        require(account != address(0), "ERC1155: burn from the zero address");

        address operator = _msgSender();

        _beforeTokenTransfer(operator, account, address(0), _asSingletonArray(id), _asSingletonArray(amount), "");

        _balances[id][account] = _balances[id][account].sub(
            amount,
            "ERC1155: burn amount exceeds balance"
        );

        emit TransferSingle(operator, account, address(0), id, amount);
    }

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {_burn}.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     */
    function _burnBatch(address account, uint256[] memory ids, uint256[] memory amounts) internal virtual {
        require(account != address(0), "ERC1155: burn from the zero address");
        require(ids.length == amounts.length, "ERC1155: ids and amounts length mismatch");

        address operator = _msgSender();

        _beforeTokenTransfer(operator, account, address(0), ids, amounts, "");

        for (uint i = 0; i < ids.length; i++) {
            _balances[ids[i]][account] = _balances[ids[i]][account].sub(
                amounts[i],
                "ERC1155: burn amount exceeds balance"
            );
        }

        emit TransferBatch(operator, account, address(0), ids, amounts);
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning, as well as batched variants.
     *
     * The same hook is called on both single and batched variants. For single
     * transfers, the length of the `id` and `amount` arrays will be 1.
     *
     * Calling conditions (for each `id` and `amount` pair):
     *
     * - When `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * of token type `id` will be  transferred to `to`.
     * - When `from` is zero, `amount` tokens of token type `id` will be minted
     * for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens of token type `id`
     * will be burned.
     * - `from` and `to` are never both zero.
     * - `ids` and `amounts` have the same, non-zero length.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address operator,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    )
        internal
        virtual
    { }

    function _doSafeTransferAcceptanceCheck(
        address operator,
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes memory data
    )
        private
    {
        if (to.isContract()) {
            try IERC1155Receiver(to).onERC1155Received(operator, from, id, amount, data) returns (bytes4 response) {
                if (response != IERC1155Receiver(to).onERC1155Received.selector) {
                    revert("ERC1155: ERC1155Receiver rejected tokens");
                }
            } catch Error(string memory reason) {
                revert(reason);
            } catch {
                revert("ERC1155: transfer to non ERC1155Receiver implementer");
            }
        }
    }

    function _doSafeBatchTransferAcceptanceCheck(
        address operator,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    )
        private
    {
        if (to.isContract()) {
            try IERC1155Receiver(to).onERC1155BatchReceived(operator, from, ids, amounts, data) returns (bytes4 response) {
                if (response != IERC1155Receiver(to).onERC1155BatchReceived.selector) {
                    revert("ERC1155: ERC1155Receiver rejected tokens");
                }
            } catch Error(string memory reason) {
                revert(reason);
            } catch {
                revert("ERC1155: transfer to non ERC1155Receiver implementer");
            }
        }
    }

    function _asSingletonArray(uint256 element) private pure returns (uint256[] memory) {
        uint256[] memory array = new uint256[](1);
        array[0] = element;

        return array;
    }
}

File 68 of 79 : IERC1155.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

import "../../introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC1155 compliant contract, as defined in the
 * https://eips.ethereum.org/EIPS/eip-1155[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155 is IERC165 {
    /**
     * @dev Emitted when `value` tokens of token type `id` are transferred from `from` to `to` by `operator`.
     */
    event TransferSingle(address indexed operator, address indexed from, address indexed to, uint256 id, uint256 value);

    /**
     * @dev Equivalent to multiple {TransferSingle} events, where `operator`, `from` and `to` are the same for all
     * transfers.
     */
    event TransferBatch(address indexed operator, address indexed from, address indexed to, uint256[] ids, uint256[] values);

    /**
     * @dev Emitted when `account` grants or revokes permission to `operator` to transfer their tokens, according to
     * `approved`.
     */
    event ApprovalForAll(address indexed account, address indexed operator, bool approved);

    /**
     * @dev Emitted when the URI for token type `id` changes to `value`, if it is a non-programmatic URI.
     *
     * If an {URI} event was emitted for `id`, the standard
     * https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[guarantees] that `value` will equal the value
     * returned by {IERC1155MetadataURI-uri}.
     */
    event URI(string value, uint256 indexed id);

    /**
     * @dev Returns the amount of tokens of token type `id` owned by `account`.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function balanceOf(address account, uint256 id) external view returns (uint256);

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {balanceOf}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(address[] calldata accounts, uint256[] calldata ids) external view returns (uint256[] memory);

    /**
     * @dev Grants or revokes permission to `operator` to transfer the caller's tokens, according to `approved`,
     *
     * Emits an {ApprovalForAll} event.
     *
     * Requirements:
     *
     * - `operator` cannot be the caller.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns true if `operator` is approved to transfer ``account``'s tokens.
     *
     * See {setApprovalForAll}.
     */
    function isApprovedForAll(address account, address operator) external view returns (bool);

    /**
     * @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If the caller is not `from`, it must be have been approved to spend ``from``'s tokens via {setApprovalForAll}.
     * - `from` must have a balance of tokens of type `id` of at least `amount`.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function safeTransferFrom(address from, address to, uint256 id, uint256 amount, bytes calldata data) external;

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {safeTransferFrom}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function safeBatchTransferFrom(address from, address to, uint256[] calldata ids, uint256[] calldata amounts, bytes calldata data) external;
}

File 69 of 79 : IERC1155MetadataURI.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

import "./IERC1155.sol";

/**
 * @dev Interface of the optional ERC1155MetadataExtension interface, as defined
 * in the https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155MetadataURI is IERC1155 {
    /**
     * @dev Returns the URI for token type `id`.
     *
     * If the `\{id\}` substring is present in the URI, it must be replaced by
     * clients with the actual token type ID.
     */
    function uri(uint256 id) external view returns (string memory);
}

File 70 of 79 : IERC1155Receiver.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../../introspection/IERC165.sol";

/**
 * _Available since v3.1._
 */
interface IERC1155Receiver is IERC165 {

    /**
        @dev Handles the receipt of a single ERC1155 token type. This function is
        called at the end of a `safeTransferFrom` after the balance has been updated.
        To accept the transfer, this must return
        `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))`
        (i.e. 0xf23a6e61, or its own function selector).
        @param operator The address which initiated the transfer (i.e. msg.sender)
        @param from The address which previously owned the token
        @param id The ID of the token being transferred
        @param value The amount of tokens being transferred
        @param data Additional data with no specified format
        @return `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))` if transfer is allowed
    */
    function onERC1155Received(
        address operator,
        address from,
        uint256 id,
        uint256 value,
        bytes calldata data
    )
        external
        returns(bytes4);

    /**
        @dev Handles the receipt of a multiple ERC1155 token types. This function
        is called at the end of a `safeBatchTransferFrom` after the balances have
        been updated. To accept the transfer(s), this must return
        `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))`
        (i.e. 0xbc197c81, or its own function selector).
        @param operator The address which initiated the batch transfer (i.e. msg.sender)
        @param from The address which previously owned the token
        @param ids An array containing ids of each token being transferred (order and length must match values array)
        @param values An array containing amounts of each token being transferred (order and length must match ids array)
        @param data Additional data with no specified format
        @return `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))` if transfer is allowed
    */
    function onERC1155BatchReceived(
        address operator,
        address from,
        uint256[] calldata ids,
        uint256[] calldata values,
        bytes calldata data
    )
        external
        returns(bytes4);
}

File 71 of 79 : UpgradeableProxy.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./Proxy.sol";
import "../utils/Address.sol";

/**
 * @dev This contract implements an upgradeable proxy. It is upgradeable because calls are delegated to an
 * implementation address that can be changed. This address is stored in storage in the location specified by
 * https://eips.ethereum.org/EIPS/eip-1967[EIP1967], so that it doesn't conflict with the storage layout of the
 * implementation behind the proxy.
 *
 * Upgradeability is only provided internally through {_upgradeTo}. For an externally upgradeable proxy see
 * {TransparentUpgradeableProxy}.
 */
contract UpgradeableProxy is Proxy {
    /**
     * @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
     *
     * If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
     * function call, and allows initializating the storage of the proxy like a Solidity constructor.
     */
    constructor(address _logic, bytes memory _data) public payable {
        assert(_IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
        _setImplementation(_logic);
        if(_data.length > 0) {
            Address.functionDelegateCall(_logic, _data);
        }
    }

    /**
     * @dev Emitted when the implementation is upgraded.
     */
    event Upgraded(address indexed implementation);

    /**
     * @dev Storage slot with the address of the current implementation.
     * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
     * validated in the constructor.
     */
    bytes32 private constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

    /**
     * @dev Returns the current implementation address.
     */
    function _implementation() internal view virtual override returns (address impl) {
        bytes32 slot = _IMPLEMENTATION_SLOT;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            impl := sload(slot)
        }
    }

    /**
     * @dev Upgrades the proxy to a new implementation.
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeTo(address newImplementation) internal virtual {
        _setImplementation(newImplementation);
        emit Upgraded(newImplementation);
    }

    /**
     * @dev Stores a new address in the EIP1967 implementation slot.
     */
    function _setImplementation(address newImplementation) private {
        require(Address.isContract(newImplementation), "UpgradeableProxy: new implementation is not a contract");

        bytes32 slot = _IMPLEMENTATION_SLOT;

        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(slot, newImplementation)
        }
    }
}

File 72 of 79 : Proxy.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
 * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
 * be specified by overriding the virtual {_implementation} function.
 *
 * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
 * different contract through the {_delegate} function.
 *
 * The success and return data of the delegated call will be returned back to the caller of the proxy.
 */
abstract contract Proxy {
    /**
     * @dev Delegates the current call to `implementation`.
     *
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _delegate(address implementation) internal virtual {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            // Copy msg.data. We take full control of memory in this inline assembly
            // block because it will not return to Solidity code. We overwrite the
            // Solidity scratch pad at memory position 0.
            calldatacopy(0, 0, calldatasize())

            // Call the implementation.
            // out and outsize are 0 because we don't know the size yet.
            let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)

            // Copy the returned data.
            returndatacopy(0, 0, returndatasize())

            switch result
            // delegatecall returns 0 on error.
            case 0 { revert(0, returndatasize()) }
            default { return(0, returndatasize()) }
        }
    }

    /**
     * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
     * and {_fallback} should delegate.
     */
    function _implementation() internal view virtual returns (address);

    /**
     * @dev Delegates the current call to the address returned by `_implementation()`.
     *
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _fallback() internal virtual {
        _beforeFallback();
        _delegate(_implementation());
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
     * function in the contract matches the call data.
     */
    fallback () external payable virtual {
        _fallback();
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
     * is empty.
     */
    receive () external payable virtual {
        _fallback();
    }

    /**
     * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
     * call, or as part of the Solidity `fallback` or `receive` functions.
     *
     * If overriden should call `super._beforeFallback()`.
     */
    function _beforeFallback() internal virtual {
    }
}

File 73 of 79 : TransparentUpgradeableProxy.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./UpgradeableProxy.sol";

/**
 * @dev This contract implements a proxy that is upgradeable by an admin.
 *
 * To avoid https://medium.com/nomic-labs-blog/malicious-backdoors-in-ethereum-proxies-62629adf3357[proxy selector
 * clashing], which can potentially be used in an attack, this contract uses the
 * https://blog.openzeppelin.com/the-transparent-proxy-pattern/[transparent proxy pattern]. This pattern implies two
 * things that go hand in hand:
 *
 * 1. If any account other than the admin calls the proxy, the call will be forwarded to the implementation, even if
 * that call matches one of the admin functions exposed by the proxy itself.
 * 2. If the admin calls the proxy, it can access the admin functions, but its calls will never be forwarded to the
 * implementation. If the admin tries to call a function on the implementation it will fail with an error that says
 * "admin cannot fallback to proxy target".
 *
 * These properties mean that the admin account can only be used for admin actions like upgrading the proxy or changing
 * the admin, so it's best if it's a dedicated account that is not used for anything else. This will avoid headaches due
 * to sudden errors when trying to call a function from the proxy implementation.
 *
 * Our recommendation is for the dedicated account to be an instance of the {ProxyAdmin} contract. If set up this way,
 * you should think of the `ProxyAdmin` instance as the real administrative interface of your proxy.
 */
contract TransparentUpgradeableProxy is UpgradeableProxy {
    /**
     * @dev Initializes an upgradeable proxy managed by `_admin`, backed by the implementation at `_logic`, and
     * optionally initialized with `_data` as explained in {UpgradeableProxy-constructor}.
     */
    constructor(address _logic, address admin_, bytes memory _data) public payable UpgradeableProxy(_logic, _data) {
        assert(_ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
        _setAdmin(admin_);
    }

    /**
     * @dev Emitted when the admin account has changed.
     */
    event AdminChanged(address previousAdmin, address newAdmin);

    /**
     * @dev Storage slot with the admin of the contract.
     * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
     * validated in the constructor.
     */
    bytes32 private constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;

    /**
     * @dev Modifier used internally that will delegate the call to the implementation unless the sender is the admin.
     */
    modifier ifAdmin() {
        if (msg.sender == _admin()) {
            _;
        } else {
            _fallback();
        }
    }

    /**
     * @dev Returns the current admin.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyAdmin}.
     *
     * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
     * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
     * `0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103`
     */
    function admin() external ifAdmin returns (address admin_) {
        admin_ = _admin();
    }

    /**
     * @dev Returns the current implementation.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyImplementation}.
     *
     * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
     * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
     * `0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc`
     */
    function implementation() external ifAdmin returns (address implementation_) {
        implementation_ = _implementation();
    }

    /**
     * @dev Changes the admin of the proxy.
     *
     * Emits an {AdminChanged} event.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-changeProxyAdmin}.
     */
    function changeAdmin(address newAdmin) external virtual ifAdmin {
        require(newAdmin != address(0), "TransparentUpgradeableProxy: new admin is the zero address");
        emit AdminChanged(_admin(), newAdmin);
        _setAdmin(newAdmin);
    }

    /**
     * @dev Upgrade the implementation of the proxy.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-upgrade}.
     */
    function upgradeTo(address newImplementation) external virtual ifAdmin {
        _upgradeTo(newImplementation);
    }

    /**
     * @dev Upgrade the implementation of the proxy, and then call a function from the new implementation as specified
     * by `data`, which should be an encoded function call. This is useful to initialize new storage variables in the
     * proxied contract.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-upgradeAndCall}.
     */
    function upgradeToAndCall(address newImplementation, bytes calldata data) external payable virtual ifAdmin {
        _upgradeTo(newImplementation);
        Address.functionDelegateCall(newImplementation, data);
    }

    /**
     * @dev Returns the current admin.
     */
    function _admin() internal view virtual returns (address adm) {
        bytes32 slot = _ADMIN_SLOT;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            adm := sload(slot)
        }
    }

    /**
     * @dev Stores a new address in the EIP1967 admin slot.
     */
    function _setAdmin(address newAdmin) private {
        bytes32 slot = _ADMIN_SLOT;

        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(slot, newAdmin)
        }
    }

    /**
     * @dev Makes sure the admin cannot access the fallback function. See {Proxy-_beforeFallback}.
     */
    function _beforeFallback() internal virtual override {
        require(msg.sender != _admin(), "TransparentUpgradeableProxy: admin cannot fallback to proxy target");
        super._beforeFallback();
    }
}

File 74 of 79 : TransparentUpgradeableProxy.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;

// Importing this file so it get compiled and get the artifact to deploy
import "@openzeppelin/contracts/proxy/TransparentUpgradeableProxy.sol";

/// @title TransparentUpgradeableProxy
///
/// @dev This contract implements the transparent proxy by openZeppelin that is upgradeable by an admin.
///         The proxy admin can update the implementation logic

File 75 of 79 : TestERC1155.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;

import "@openzeppelin/contracts/token/ERC1155/ERC1155.sol";

contract TestERC1155 is ERC1155 {
    constructor() ERC1155("https://testERC1155/") {
        _mint(msg.sender, 1, 10, "");
    }
}

File 76 of 79 : AccessControlBasedWhitelist.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/access/AccessControl.sol";
import "../interfaces/IWhitelist.sol";

/// @title AccessControlBasedWhitelist
///
/// @dev This contract is based in OpenZeppelin AccessControl that allows to implement role-based access

contract AccessControlBasedWhitelist is IWhitelist, AccessControl {
    // Create a new role identifier for the transfer role
    bytes32 public constant TRANSFER_ROLE = keccak256("TRANSFER_ROLE");

    constructor(address _trader) {
        require(_trader != address(0), "invalid address");
        // Grant the transfer role to a specified account
        _setupRole(TRANSFER_ROLE, _trader);
        // Grant the contract deployer the default admin role: it will be able
        // to grant and revoke any roles
        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);
    }

    /**
     * @param _who the address that wants to transfer a NFT
     * @dev Returns true if address has permission to transfer a NFT
     */
    function canTransfer(address _who) external view override returns (bool) {
        return hasRole(TRANSFER_ROLE, _who);
    }
}

File 77 of 79 : TestWhitelist.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

import "../interfaces/IWhitelist.sol";

/* solhint-disable */

///This whitelist is for test updating whitelistProxy to allow any address to transfer
contract TestWhitelist is IWhitelist {
    function canTransfer(address) external pure override returns (bool) {
        return true;
    }
}

File 78 of 79 : TestERC721.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity ^0.7.6;

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";

contract TestERC721 is ERC721 {
    constructor() ERC721("TestERC721", "TEST") {
        _safeMint(msg.sender, 1);
    }
}

File 79 of 79 : TestToken.sol
// SPDX-License-Identifier:UNLICENSED
pragma solidity 0.7.6;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract TestToken is ERC20 {
    constructor(string memory name_, string memory symbol_) ERC20(name_, symbol_) {
        _mint(msg.sender, 1e10);
    }
}

Settings
{
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "outputSelection": {
    "*": {
      "*": [
        "evm.bytecode",
        "evm.deployedBytecode",
        "devdoc",
        "userdoc",
        "metadata",
        "abi"
      ]
    }
  },
  "metadata": {
    "useLiteralContent": true
  },
  "libraries": {
    "": {
      "__CACHE_BREAKER__": "0x00000000d41867734bbee4c6863d9255b2b06ac1"
    }
  }
}

Contract ABI

[{"inputs":[{"internalType":"address","name":"_logic","type":"address"},{"internalType":"address","name":"admin_","type":"address"},{"internalType":"bytes","name":"_data","type":"bytes"}],"stateMutability":"payable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"previousAdmin","type":"address"},{"indexed":false,"internalType":"address","name":"newAdmin","type":"address"}],"name":"AdminChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"implementation","type":"address"}],"name":"Upgraded","type":"event"},{"stateMutability":"payable","type":"fallback"},{"inputs":[],"name":"admin","outputs":[{"internalType":"address","name":"admin_","type":"address"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"newAdmin","type":"address"}],"name":"changeAdmin","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"implementation","outputs":[{"internalType":"address","name":"implementation_","type":"address"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"newImplementation","type":"address"}],"name":"upgradeTo","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"newImplementation","type":"address"},{"internalType":"bytes","name":"data","type":"bytes"}],"name":"upgradeToAndCall","outputs":[],"stateMutability":"payable","type":"function"},{"stateMutability":"payable","type":"receive"}]

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Block Transaction Gas Used Reward
Age Block Fee Address BC Fee Address Voting Power Jailed Incoming
Block Uncle Number Difficulty Gas Used Reward
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