ETH Price: $2,555.19 (+1.22%)

Transaction Decoder

Block:
13372103 at Oct-07-2021 01:35:45 PM +UTC
Transaction Fee:
0.008274458856670578 ETH $21.14
Gas Used:
60,489 Gas / 136.792786402 Gwei

Emitted Events:

182 AdminUpgradeabilityProxy.0x26ea3ebbda62eb1baef13e1c237dddd956c87f80b2801f2616d806d52557b121( 0x26ea3ebbda62eb1baef13e1c237dddd956c87f80b2801f2616d806d52557b121, 0x0000000000000000000000000000000000000000000000000000000000017b3a, 0x0000000000000000000000002b3d6391020c2aa61411bf31c38b0da66fb81813, 00000000000000000000000000000000000000000000000004bbd4a48ce2c000, 00000000000000000000000000000000000000000000000000000000615f8437 )

Account State Difference:

  Address   Before After State Difference Code
(Hiveon Pool)
5,823.898909731529598554 Eth5,823.899000465029598554 Eth0.0000907335
0x2b3D6391...66Fb81813
0.628894041318886425 Eth
Nonce: 3
0.279519582462215847 Eth
Nonce: 4
0.349374458856670578
0x4e0d7CB3...71a229242 2.181753852016747607 Eth2.491753852016747607 Eth0.31
0xcDA72070...3623d0B6f
(Foundation: Market)
200.96918 Eth201.00028 Eth0.0311

Execution Trace

ETH 0.3411 AdminUpgradeabilityProxy.9979ef45( )
  • ETH 0.3411 FNDNFTMarket.placeBid( auctionId=97082 )
    • ETH 0.31 0x4e0d7cb37ddd8cfa5786455b04acf8871a229242.CALL( )
      File 1 of 2: AdminUpgradeabilityProxy
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.6.0;
      import './UpgradeabilityProxy.sol';
      /**
       * @title AdminUpgradeabilityProxy
       * @dev This contract combines an upgradeability proxy with an authorization
       * mechanism for administrative tasks.
       * All external functions in this contract must be guarded by the
       * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
       * feature proposal that would enable this to be done automatically.
       */
      contract AdminUpgradeabilityProxy is UpgradeabilityProxy {
        /**
         * Contract constructor.
         * @param _logic address of the initial implementation.
         * @param _admin Address of the proxy administrator.
         * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
         * It should include the signature and the parameters of the function to be called, as described in
         * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
         * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
         */
        constructor(address _logic, address _admin, bytes memory _data) UpgradeabilityProxy(_logic, _data) public payable {
          assert(ADMIN_SLOT == bytes32(uint256(keccak256('eip1967.proxy.admin')) - 1));
          _setAdmin(_admin);
        }
        /**
         * @dev Emitted when the administration has been transferred.
         * @param previousAdmin Address of the previous admin.
         * @param newAdmin Address of the new admin.
         */
        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 internal constant ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
        /**
         * @dev Modifier to check whether the `msg.sender` is the admin.
         * If it is, it will run the function. Otherwise, it will delegate the call
         * to the implementation.
         */
        modifier ifAdmin() {
          if (msg.sender == _admin()) {
            _;
          } else {
            _fallback();
          }
        }
        /**
         * @return The address of the proxy admin.
         */
        function admin() external ifAdmin returns (address) {
          return _admin();
        }
        /**
         * @return The address of the implementation.
         */
        function implementation() external ifAdmin returns (address) {
          return _implementation();
        }
        /**
         * @dev Changes the admin of the proxy.
         * Only the current admin can call this function.
         * @param newAdmin Address to transfer proxy administration to.
         */
        function changeAdmin(address newAdmin) external ifAdmin {
          require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
          emit AdminChanged(_admin(), newAdmin);
          _setAdmin(newAdmin);
        }
        /**
         * @dev Upgrade the backing implementation of the proxy.
         * Only the admin can call this function.
         * @param newImplementation Address of the new implementation.
         */
        function upgradeTo(address newImplementation) external ifAdmin {
          _upgradeTo(newImplementation);
        }
        /**
         * @dev Upgrade the backing implementation of the proxy and call a function
         * on the new implementation.
         * This is useful to initialize the proxied contract.
         * @param newImplementation Address of the new implementation.
         * @param data Data to send as msg.data in the low level call.
         * It should include the signature and the parameters of the function to be called, as described in
         * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
         */
        function upgradeToAndCall(address newImplementation, bytes calldata data) payable external ifAdmin {
          _upgradeTo(newImplementation);
          (bool success,) = newImplementation.delegatecall(data);
          require(success);
        }
        /**
         * @return adm The admin slot.
         */
        function _admin() internal view returns (address adm) {
          bytes32 slot = ADMIN_SLOT;
          assembly {
            adm := sload(slot)
          }
        }
        /**
         * @dev Sets the address of the proxy admin.
         * @param newAdmin Address of the new proxy admin.
         */
        function _setAdmin(address newAdmin) internal {
          bytes32 slot = ADMIN_SLOT;
          assembly {
            sstore(slot, newAdmin)
          }
        }
        /**
         * @dev Only fall back when the sender is not the admin.
         */
        function _willFallback() internal override virtual {
          require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
          super._willFallback();
        }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.6.0;
      import './Proxy.sol';
      import '@openzeppelin/contracts/utils/Address.sol';
      /**
       * @title UpgradeabilityProxy
       * @dev This contract implements a proxy that allows to change the
       * implementation address to which it will delegate.
       * Such a change is called an implementation upgrade.
       */
      contract UpgradeabilityProxy is Proxy {
        /**
         * @dev Contract constructor.
         * @param _logic Address of the initial implementation.
         * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
         * It should include the signature and the parameters of the function to be called, as described in
         * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
         * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
         */
        constructor(address _logic, bytes memory _data) public payable {
          assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1));
          _setImplementation(_logic);
          if(_data.length > 0) {
            (bool success,) = _logic.delegatecall(_data);
            require(success);
          }
        }  
        /**
         * @dev Emitted when the implementation is upgraded.
         * @param implementation Address of the new implementation.
         */
        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 internal constant IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
        /**
         * @dev Returns the current implementation.
         * @return impl Address of the current implementation
         */
        function _implementation() internal override view returns (address impl) {
          bytes32 slot = IMPLEMENTATION_SLOT;
          assembly {
            impl := sload(slot)
          }
        }
        /**
         * @dev Upgrades the proxy to a new implementation.
         * @param newImplementation Address of the new implementation.
         */
        function _upgradeTo(address newImplementation) internal {
          _setImplementation(newImplementation);
          emit Upgraded(newImplementation);
        }
        /**
         * @dev Sets the implementation address of the proxy.
         * @param newImplementation Address of the new implementation.
         */
        function _setImplementation(address newImplementation) internal {
          require(Address.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");
          bytes32 slot = IMPLEMENTATION_SLOT;
          assembly {
            sstore(slot, newImplementation)
          }
        }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.6.0;
      /**
       * @title Proxy
       * @dev Implements delegation of calls to other contracts, with proper
       * forwarding of return values and bubbling of failures.
       * It defines a fallback function that delegates all calls to the address
       * returned by the abstract _implementation() internal function.
       */
      abstract contract Proxy {
        /**
         * @dev Fallback function.
         * Implemented entirely in `_fallback`.
         */
        fallback () payable external {
          _fallback();
        }
        /**
         * @dev Receive function.
         * Implemented entirely in `_fallback`.
         */
        receive () payable external {
          _fallback();
        }
        /**
         * @return The Address of the implementation.
         */
        function _implementation() internal virtual view returns (address);
        /**
         * @dev Delegates execution to an implementation contract.
         * This is a low level function that doesn't return to its internal call site.
         * It will return to the external caller whatever the implementation returns.
         * @param implementation Address to delegate.
         */
        function _delegate(address implementation) internal {
          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 Function that is run as the first thing in the fallback function.
         * Can be redefined in derived contracts to add functionality.
         * Redefinitions must call super._willFallback().
         */
        function _willFallback() internal virtual {
        }
        /**
         * @dev fallback implementation.
         * Extracted to enable manual triggering.
         */
        function _fallback() internal {
          _willFallback();
          _delegate(_implementation());
        }
      }
      // 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);
          }
          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 2 of 2: FNDNFTMarket
      /*
        ・
         * ★
            ・ 。
               ・ ゚☆ 。
            * ★ ゚・。 *  。
                  * ☆ 。・゚*.。
               ゚ *.。☆。★ ・
      ​
                            `                     .-:::::-.`              `-::---...```
                           `-:`               .:+ssssoooo++//:.`       .-/+shhhhhhhhhhhhhyyyssooo:
                          .--::.            .+ossso+/////++/:://-`   .////+shhhhhhhhhhhhhhhhhhhhhy
                        `-----::.         `/+////+++///+++/:--:/+/-  -////+shhhhhhhhhhhhhhhhhhhhhy
                       `------:::-`      `//-.``.-/+ooosso+:-.-/oso- -////+shhhhhhhhhhhhhhhhhhhhhy
                      .--------:::-`     :+:.`  .-/osyyyyyyso++syhyo.-////+shhhhhhhhhhhhhhhhhhhhhy
                    `-----------:::-.    +o+:-.-:/oyhhhhhhdhhhhhdddy:-////+shhhhhhhhhhhhhhhhhhhhhy
                   .------------::::--  `oys+/::/+shhhhhhhdddddddddy/-////+shhhhhhhhhhhhhhhhhhhhhy
                  .--------------:::::-` +ys+////+yhhhhhhhddddddddhy:-////+yhhhhhhhhhhhhhhhhhhhhhy
                `----------------::::::-`.ss+/:::+oyhhhhhhhhhhhhhhho`-////+shhhhhhhhhhhhhhhhhhhhhy
               .------------------:::::::.-so//::/+osyyyhhhhhhhhhys` -////+shhhhhhhhhhhhhhhhhhhhhy
             `.-------------------::/:::::..+o+////+oosssyyyyyyys+`  .////+shhhhhhhhhhhhhhhhhhhhhy
             .--------------------::/:::.`   -+o++++++oooosssss/.     `-//+shhhhhhhhhhhhhhhhhhhhyo
           .-------   ``````.......--`        `-/+ooooosso+/-`          `./++++///:::--...``hhhhyo
                                                    `````
         * 
            ・ 。
          ・  ゚☆ 。
            * ★ ゚・。 *  。
                  * ☆ 。・゚*.。
               ゚ *.。☆。★ ・
          *  ゚。·*・。 ゚*
           ☆゚・。°*. ゚
        ・ ゚*。・゚★。
        ・ *゚。   *
       ・゚*。★・
       ☆∴。 *
      ・ 。
      */
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      pragma abicoder v2; // solhint-disable-line
      import "@openzeppelin/contracts-upgradeable/utils/ReentrancyGuardUpgradeable.sol";
      import "./mixins/FoundationTreasuryNode.sol";
      import "./mixins/roles/FoundationAdminRole.sol";
      import "./mixins/roles/FoundationOperatorRole.sol";
      import "./mixins/NFTMarketCore.sol";
      import "./mixins/SendValueWithFallbackWithdraw.sol";
      import "./mixins/NFTMarketCreators.sol";
      import "./mixins/NFTMarketFees.sol";
      import "./mixins/NFTMarketAuction.sol";
      import "./mixins/NFTMarketReserveAuction.sol";
      import "./mixins/AccountMigration.sol";
      import "./mixins/NFTMarketPrivateSale.sol";
      /**
       * @title A market for NFTs on Foundation.
       * @dev This top level file holds no data directly to ease future upgrades.
       */
      contract FNDNFTMarket is
        FoundationTreasuryNode,
        FoundationAdminRole,
        FoundationOperatorRole,
        AccountMigration,
        NFTMarketCore,
        ReentrancyGuardUpgradeable,
        NFTMarketCreators,
        SendValueWithFallbackWithdraw,
        NFTMarketFees,
        NFTMarketAuction,
        NFTMarketReserveAuction,
        NFTMarketPrivateSale
      {
        /**
         * @notice Called once to configure the contract after the initial deployment.
         * @dev This farms the initialize call out to inherited contracts as needed.
         */
        function initialize(address payable treasury) public initializer {
          FoundationTreasuryNode._initializeFoundationTreasuryNode(treasury);
          NFTMarketAuction._initializeNFTMarketAuction();
          NFTMarketReserveAuction._initializeNFTMarketReserveAuction();
        }
        /**
         * @notice Allows Foundation to update the market configuration.
         */
        function adminUpdateConfig(
          uint256 minPercentIncrementInBasisPoints,
          uint256 duration,
          uint256 primaryF8nFeeBasisPoints,
          uint256 secondaryF8nFeeBasisPoints,
          uint256 secondaryCreatorFeeBasisPoints
        ) public onlyFoundationAdmin {
          // It's okay to call _reinitialize multiple times, but it must be called at least once after upgrade
          _reinitialize();
          _updateReserveAuctionConfig(minPercentIncrementInBasisPoints, duration);
          _updateMarketFees(primaryF8nFeeBasisPoints, secondaryF8nFeeBasisPoints, secondaryCreatorFeeBasisPoints);
        }
        /**
         * @dev Checks who the seller for an NFT is, this will check escrow or return the current owner if not in escrow.
         * This is a no-op function required to avoid compile errors.
         */
        function _getSellerFor(address nftContract, uint256 tokenId)
          internal
          view
          virtual
          override(NFTMarketCore, NFTMarketReserveAuction)
          returns (address payable)
        {
          return super._getSellerFor(nftContract, tokenId);
        }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.7.0;
      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;
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      import "@openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
      import "@openzeppelin/contracts-upgradeable/utils/AddressUpgradeable.sol";
      /**
       * @notice A mixin that stores a reference to the Foundation treasury contract.
       */
      abstract contract FoundationTreasuryNode is Initializable {
        using AddressUpgradeable for address payable;
        address payable private treasury;
        /**
         * @dev Called once after the initial deployment to set the Foundation treasury address.
         */
        function _initializeFoundationTreasuryNode(address payable _treasury) internal initializer {
          require(_treasury.isContract(), "FoundationTreasuryNode: Address is not a contract");
          treasury = _treasury;
        }
        /**
         * @notice Returns the address of the Foundation treasury.
         */
        function getFoundationTreasury() public view returns (address payable) {
          return treasury;
        }
        // `______gap` is added to each mixin to allow adding new data slots or additional mixins in an upgrade-safe way.
        uint256[2000] private __gap;
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      import "../../interfaces/IAdminRole.sol";
      import "../FoundationTreasuryNode.sol";
      /**
       * @notice Allows a contract to leverage the admin role defined by the Foundation treasury.
       */
      abstract contract FoundationAdminRole is FoundationTreasuryNode {
        // This file uses 0 data slots (other than what's included via FoundationTreasuryNode)
        modifier onlyFoundationAdmin() {
          require(_isFoundationAdmin(), "FoundationAdminRole: caller does not have the Admin role");
          _;
        }
        function _isFoundationAdmin() internal view returns (bool) {
          return IAdminRole(getFoundationTreasury()).isAdmin(msg.sender);
        }
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      import "../../interfaces/IOperatorRole.sol";
      import "../FoundationTreasuryNode.sol";
      /**
       * @notice Allows a contract to leverage the operator role defined by the Foundation treasury.
       */
      abstract contract FoundationOperatorRole is FoundationTreasuryNode {
        // This file uses 0 data slots (other than what's included via FoundationTreasuryNode)
        function _isFoundationOperator() internal view returns (bool) {
          return IOperatorRole(getFoundationTreasury()).isOperator(msg.sender);
        }
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      import "@openzeppelin/contracts-upgradeable/token/ERC721/IERC721Upgradeable.sol";
      /**
       * @notice 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 {
        /**
         * @dev If the auction did not have an escrowed seller to return, this falls back to return the current owner.
         * This allows functions to calculate the correct fees before the NFT has been listed in auction.
         */
        function _getSellerFor(address nftContract, uint256 tokenId) internal view virtual returns (address payable) {
          return payable(IERC721Upgradeable(nftContract).ownerOf(tokenId));
        }
        // 50 slots were consumed by adding ReentrancyGuardUpgradeable
        uint256[950] private ______gap;
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      import "@openzeppelin/contracts-upgradeable/utils/AddressUpgradeable.sol";
      import "@openzeppelin/contracts-upgradeable/math/SafeMathUpgradeable.sol";
      import "@openzeppelin/contracts-upgradeable/utils/ReentrancyGuardUpgradeable.sol";
      /**
       * @notice Attempt to send ETH and if the transfer fails or runs out of gas, store the balance
       * for future withdrawal instead.
       */
      abstract contract SendValueWithFallbackWithdraw is ReentrancyGuardUpgradeable {
        using AddressUpgradeable for address payable;
        using SafeMathUpgradeable for uint256;
        mapping(address => uint256) private pendingWithdrawals;
        event WithdrawPending(address indexed user, uint256 amount);
        event Withdrawal(address indexed user, uint256 amount);
        /**
         * @notice Returns how much funds are available for manual withdraw due to failed transfers.
         */
        function getPendingWithdrawal(address user) public view returns (uint256) {
          return pendingWithdrawals[user];
        }
        /**
         * @notice Allows a user to manually withdraw funds which originally failed to transfer to themselves.
         */
        function withdraw() public {
          withdrawFor(msg.sender);
        }
        /**
         * @notice Allows anyone to manually trigger a withdrawal of funds which originally failed to transfer for a user.
         */
        function withdrawFor(address payable user) public nonReentrant {
          uint256 amount = pendingWithdrawals[user];
          require(amount > 0, "No funds are pending withdrawal");
          pendingWithdrawals[user] = 0;
          user.sendValue(amount);
          emit Withdrawal(user, amount);
        }
        /**
         * @dev Attempt to send a user ETH with a reasonably low gas limit of 20k,
         * which is enough to send to contracts as well.
         */
        function _sendValueWithFallbackWithdrawWithLowGasLimit(address payable user, uint256 amount) internal {
          _sendValueWithFallbackWithdraw(user, amount, 20000);
        }
        /**
         * @dev Attempt to send a user or contract ETH with a moderate gas limit of 90k,
         * which is enough for a 5-way split.
         */
        function _sendValueWithFallbackWithdrawWithMediumGasLimit(address payable user, uint256 amount) internal {
          _sendValueWithFallbackWithdraw(user, amount, 210000);
        }
        /**
         * @dev Attempt to send a user or contract ETH and if it fails store the amount owned for later withdrawal.
         */
        function _sendValueWithFallbackWithdraw(
          address payable user,
          uint256 amount,
          uint256 gasLimit
        ) private {
          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) {
            // Record failed sends for a withdrawal later
            // Transfers could fail if sent to a multisig with non-trivial receiver logic
            // solhint-disable-next-line reentrancy
            pendingWithdrawals[user] = pendingWithdrawals[user].add(amount);
            emit WithdrawPending(user, amount);
          }
        }
        uint256[499] private ______gap;
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      import "../interfaces/IFNDNFT721.sol";
      import "../interfaces/ITokenCreatorPaymentAddress.sol";
      import "../interfaces/ITokenCreator.sol";
      import "../interfaces/IGetRoyalties.sol";
      import "../interfaces/IHasSecondarySaleFees.sol";
      import "../interfaces/IOwnable.sol";
      import "@openzeppelin/contracts/access/Ownable.sol";
      import "@openzeppelin/contracts-upgradeable/utils/ReentrancyGuardUpgradeable.sol";
      import "./OZ/ERC165Checker.sol";
      import "./Constants.sol";
      /**
       * @notice A mixin for associating creators to NFTs.
       * @dev In the future this may store creators directly in order to support NFTs created on a different platform.
       */
      abstract contract NFTMarketCreators is
        Constants,
        ReentrancyGuardUpgradeable // Adding this unused mixin to help with linearization
      {
        using ERC165Checker for address;
        /**
         * @dev Returns the destination address for any payments to the creator,
         * or address(0) if the destination is unknown.
         * It also checks if the current seller is the creator for isPrimary checks.
         */
        // solhint-disable-next-line code-complexity
        function _getCreatorPaymentInfo(
          address nftContract,
          uint256 tokenId,
          address seller
        )
          internal
          view
          returns (
            address payable[] memory recipients,
            uint256[] memory splitPerRecipientInBasisPoints,
            bool isCreator
          )
        {
          // All NFTs implement 165 so we skip that check, individual interfaces should return false if 165 is not implemented
          // 1st priority: getTokenCreatorPaymentAddress w/ 165
          if (nftContract.supportsERC165Interface(type(ITokenCreatorPaymentAddress).interfaceId)) {
            try
              ITokenCreatorPaymentAddress(nftContract).getTokenCreatorPaymentAddress{ gas: READ_ONLY_GAS_LIMIT }(tokenId)
            returns (address payable tokenCreatorPaymentAddress) {
              if (tokenCreatorPaymentAddress != address(0)) {
                recipients = new address payable[](1);
                recipients[0] = tokenCreatorPaymentAddress;
                if (tokenCreatorPaymentAddress == seller) {
                  // splitPerRecipientInBasisPoints is not relevant when only 1 recipient is defined
                  return (recipients, splitPerRecipientInBasisPoints, true);
                }
                // else persist recipients but look for other isCreator definitions
              }
            } catch // solhint-disable-next-line no-empty-blocks
            {
              // Fall through
            }
          }
          // 2nd priority: tokenCreator w/ 165
          if (nftContract.supportsERC165Interface(type(ITokenCreator).interfaceId)) {
            try IFNDNFT721(nftContract).tokenCreator{ gas: READ_ONLY_GAS_LIMIT }(tokenId) returns (address payable _creator) {
              if (_creator != address(0)) {
                if (recipients.length == 0) {
                  // Only pay the tokenCreator if there wasn't a tokenCreatorPaymentAddress defined
                  recipients = new address payable[](1);
                  recipients[0] = _creator;
                }
                // splitPerRecipientInBasisPoints is not relevant when only 1 recipient is defined
                return (recipients, splitPerRecipientInBasisPoints, _creator == seller);
              }
            } catch // solhint-disable-next-line no-empty-blocks
            {
              // Fall through
            }
          }
          // 3rd priority: getRoyalties
          if (recipients.length == 0 && nftContract.supportsERC165Interface(type(IGetRoyalties).interfaceId)) {
            try IGetRoyalties(nftContract).getRoyalties{ gas: READ_ONLY_GAS_LIMIT }(tokenId) returns (
              address payable[] memory _recipients,
              uint256[] memory recipientBasisPoints
            ) {
              if (_recipients.length > 0 && _recipients.length == recipientBasisPoints.length) {
                bool hasRecipient = false;
                for (uint256 i = 0; i < _recipients.length; i++) {
                  if (_recipients[i] != address(0)) {
                    hasRecipient = true;
                    if (_recipients[i] == seller) {
                      isCreator = true;
                    }
                  }
                }
                if (hasRecipient) {
                  return (_recipients, recipientBasisPoints, isCreator);
                }
              }
            } catch // solhint-disable-next-line no-empty-blocks
            {
              // Fall through
            }
          }
          // 4th priority: getFee*
          if (recipients.length == 0 && nftContract.supportsERC165Interface(type(IHasSecondarySaleFees).interfaceId)) {
            try IHasSecondarySaleFees(nftContract).getFeeRecipients{ gas: READ_ONLY_GAS_LIMIT }(tokenId) returns (
              address payable[] memory _recipients
            ) {
              if (_recipients.length > 0) {
                try IHasSecondarySaleFees(nftContract).getFeeBps{ gas: READ_ONLY_GAS_LIMIT }(tokenId) returns (
                  uint256[] memory recipientBasisPoints
                ) {
                  if (_recipients.length == recipientBasisPoints.length) {
                    bool hasRecipient = false;
                    for (uint256 i = 0; i < _recipients.length; i++) {
                      if (_recipients[i] != address(0)) {
                        hasRecipient = true;
                        if (_recipients[i] == seller) {
                          isCreator = true;
                        }
                      }
                    }
                    if (hasRecipient) {
                      return (_recipients, recipientBasisPoints, isCreator);
                    }
                  }
                } catch // solhint-disable-next-line no-empty-blocks
                {
                  // Fall through
                }
              }
            } catch // solhint-disable-next-line no-empty-blocks
            {
              // Fall through
            }
          }
          // 5th priority: owner
          try IOwnable(nftContract).owner{ gas: READ_ONLY_GAS_LIMIT }() returns (address owner) {
            if (owner != address(0)) {
              if (recipients.length == 0) {
                // Only pay the owner if there wasn't a tokenCreatorPaymentAddress defined
                recipients = new address payable[](1);
                recipients[0] = payable(owner);
              }
              // splitPerRecipientInBasisPoints is not relevant when only 1 recipient is defined
              return (recipients, splitPerRecipientInBasisPoints, owner == seller);
            }
          } catch // solhint-disable-next-line no-empty-blocks
          {
            // Fall through
          }
          // 6th priority: tokenCreator w/o requiring 165
          try IFNDNFT721(nftContract).tokenCreator{ gas: READ_ONLY_GAS_LIMIT }(tokenId) returns (address payable _creator) {
            if (_creator != address(0)) {
              if (recipients.length == 0) {
                // Only pay the tokenCreator if there wasn't a tokenCreatorPaymentAddress defined
                recipients = new address payable[](1);
                recipients[0] = _creator;
              }
              // splitPerRecipientInBasisPoints is not relevant when only 1 recipient is defined
              return (recipients, splitPerRecipientInBasisPoints, _creator == seller);
            }
          } catch // solhint-disable-next-line no-empty-blocks
          {
            // Fall through
          }
          // If no valid payment address or creator is found, return 0 recipients
        }
        // 500 slots were added via the new SendValueWithFallbackWithdraw mixin
        uint256[500] private ______gap;
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      import "@openzeppelin/contracts-upgradeable/math/SafeMathUpgradeable.sol";
      import "@openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
      import "@openzeppelin/contracts-upgradeable/token/ERC721/IERC721Upgradeable.sol";
      import "./FoundationTreasuryNode.sol";
      import "./Constants.sol";
      import "./NFTMarketCore.sol";
      import "./NFTMarketCreators.sol";
      import "./SendValueWithFallbackWithdraw.sol";
      /**
       * @notice A mixin to distribute funds when an NFT is sold.
       */
      abstract contract NFTMarketFees is
        Constants,
        Initializable,
        FoundationTreasuryNode,
        NFTMarketCore,
        NFTMarketCreators,
        SendValueWithFallbackWithdraw
      {
        using SafeMathUpgradeable for uint256;
        uint256 private _primaryFoundationFeeBasisPoints;
        uint256 private _secondaryFoundationFeeBasisPoints;
        uint256 private _secondaryCreatorFeeBasisPoints;
        mapping(address => mapping(uint256 => bool)) private nftContractToTokenIdToFirstSaleCompleted;
        event MarketFeesUpdated(
          uint256 primaryFoundationFeeBasisPoints,
          uint256 secondaryFoundationFeeBasisPoints,
          uint256 secondaryCreatorFeeBasisPoints
        );
        /**
         * @notice Returns true if the given NFT has not been sold in this market previously and is being sold by the creator.
         */
        function getIsPrimary(address nftContract, uint256 tokenId) public view returns (bool isPrimary) {
          address payable seller = _getSellerFor(nftContract, tokenId);
          bool isCreator;
          (, , isCreator) = _getCreatorPaymentInfo(nftContract, tokenId, seller);
          isPrimary = isCreator && !nftContractToTokenIdToFirstSaleCompleted[nftContract][tokenId];
        }
        /**
         * @notice Returns the current fee configuration in basis points.
         */
        function getFeeConfig()
          public
          view
          returns (
            uint256 primaryFoundationFeeBasisPoints,
            uint256 secondaryFoundationFeeBasisPoints,
            uint256 secondaryCreatorFeeBasisPoints
          )
        {
          return (_primaryFoundationFeeBasisPoints, _secondaryFoundationFeeBasisPoints, _secondaryCreatorFeeBasisPoints);
        }
        /**
         * @notice Returns how funds will be distributed for an Auction sale at the given price point.
         * @dev This is required for backwards compatibility with subgraph.
         */
        function getFees(
          address nftContract,
          uint256 tokenId,
          uint256 price
        )
          public
          view
          returns (
            uint256 foundationFee,
            uint256 creatorRev,
            uint256 ownerRev
          )
        {
          address payable seller = _getSellerFor(nftContract, tokenId);
          (foundationFee, , , creatorRev, , ownerRev) = _getFees(nftContract, tokenId, seller, price);
        }
        /**
         * @dev Calculates how funds should be distributed for the given sale details.
         */
        function _getFees(
          address nftContract,
          uint256 tokenId,
          address payable seller,
          uint256 price
        )
          private
          view
          returns (
            uint256 foundationFee,
            address payable[] memory creatorRecipients,
            uint256[] memory creatorShares,
            uint256 creatorRev,
            address payable ownerRevTo,
            uint256 ownerRev
          )
        {
          bool isCreator;
          (creatorRecipients, creatorShares, isCreator) = _getCreatorPaymentInfo(nftContract, tokenId, seller);
          bool isPrimary = isCreator && !nftContractToTokenIdToFirstSaleCompleted[nftContract][tokenId];
          // The SafeMath usage below should only be applicable if a huge (unrealistic) price is used
          // or fees are misconfigured.
          // Calculate the Foundation fee
          foundationFee =
            price.mul(isPrimary ? _primaryFoundationFeeBasisPoints : _secondaryFoundationFeeBasisPoints) /
            BASIS_POINTS;
          // Calculate the Creator revenue.
          if (isPrimary) {
            creatorRev = price.sub(foundationFee);
            // The owner is the creator so ownerRev is not broken out here.
          } else {
            if (creatorRecipients.length > 0) {
              if (isCreator) {
                // Non-primary sales by the creator should go to the payment address.
                creatorRev = price.sub(foundationFee);
              } else {
                creatorRev = price.mul(_secondaryCreatorFeeBasisPoints) / BASIS_POINTS;
                // If a secondary sale, calculate the owner revenue.
                ownerRevTo = seller;
                ownerRev = price.sub(foundationFee).sub(creatorRev);
              }
            } else {
              // If a secondary sale, calculate the owner revenue.
              ownerRevTo = seller;
              ownerRev = price.sub(foundationFee);
            }
          }
        }
        /**
         * @dev Distributes funds to foundation, creator, and NFT owner after a sale.
         * This call will respect the creator's payment address if defined.
         */
        // solhint-disable-next-line code-complexity
        function _distributeFunds(
          address nftContract,
          uint256 tokenId,
          address payable seller,
          uint256 price
        )
          internal
          returns (
            uint256 foundationFee,
            uint256 creatorFee,
            uint256 ownerRev
          )
        {
          address payable[] memory creatorRecipients;
          uint256[] memory creatorShares;
          address payable ownerRevTo;
          (foundationFee, creatorRecipients, creatorShares, creatorFee, ownerRevTo, ownerRev) = _getFees(
            nftContract,
            tokenId,
            seller,
            price
          );
          // Anytime fees are distributed that indicates the first sale is complete,
          // which will not change state during a secondary sale.
          // This must come after the `_getFees` call above as this state is considered in the function.
          nftContractToTokenIdToFirstSaleCompleted[nftContract][tokenId] = true;
          _sendValueWithFallbackWithdrawWithLowGasLimit(getFoundationTreasury(), foundationFee);
          if (creatorFee > 0) {
            if (creatorRecipients.length > 1) {
              uint256 maxCreatorIndex = creatorRecipients.length - 1;
              if (maxCreatorIndex > MAX_CREATOR_INDEX) {
                maxCreatorIndex = MAX_CREATOR_INDEX;
              }
              // Determine the total shares defined so it can be leveraged to distribute below
              uint256 totalShares;
              for (uint256 i = 0; i <= maxCreatorIndex; i++) {
                if (creatorShares[i] > BASIS_POINTS) {
                  // If the numbers are >100% we ignore the fee recipients and pay just the first instead
                  maxCreatorIndex = 0;
                  break;
                }
                totalShares = totalShares.add(creatorShares[i]);
              }
              if (totalShares == 0) {
                maxCreatorIndex = 0;
              }
              // Send payouts to each additional recipient if more than 1 was defined
              uint256 totalDistributed;
              for (uint256 i = 1; i <= maxCreatorIndex; i++) {
                uint256 share = (creatorFee.mul(creatorShares[i])) / totalShares;
                totalDistributed = totalDistributed.add(share);
                _sendValueWithFallbackWithdrawWithMediumGasLimit(creatorRecipients[i], share);
              }
              // Send the remainder to the 1st creator, rounding in their favor
              _sendValueWithFallbackWithdrawWithMediumGasLimit(creatorRecipients[0], creatorFee.sub(totalDistributed));
            } else {
              _sendValueWithFallbackWithdrawWithMediumGasLimit(creatorRecipients[0], creatorFee);
            }
          }
          _sendValueWithFallbackWithdrawWithMediumGasLimit(ownerRevTo, ownerRev);
        }
        /**
         * @notice Allows Foundation to change the market fees.
         */
        function _updateMarketFees(
          uint256 primaryFoundationFeeBasisPoints,
          uint256 secondaryFoundationFeeBasisPoints,
          uint256 secondaryCreatorFeeBasisPoints
        ) internal {
          require(primaryFoundationFeeBasisPoints < BASIS_POINTS, "NFTMarketFees: Fees >= 100%");
          require(
            secondaryFoundationFeeBasisPoints.add(secondaryCreatorFeeBasisPoints) < BASIS_POINTS,
            "NFTMarketFees: Fees >= 100%"
          );
          _primaryFoundationFeeBasisPoints = primaryFoundationFeeBasisPoints;
          _secondaryFoundationFeeBasisPoints = secondaryFoundationFeeBasisPoints;
          _secondaryCreatorFeeBasisPoints = secondaryCreatorFeeBasisPoints;
          emit MarketFeesUpdated(
            primaryFoundationFeeBasisPoints,
            secondaryFoundationFeeBasisPoints,
            secondaryCreatorFeeBasisPoints
          );
        }
        uint256[1000] private ______gap;
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      /**
       * @notice 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;
        function _initializeNFTMarketAuction() internal {
          nextAuctionId = 1;
        }
        function _getNextAndIncrementAuctionId() internal returns (uint256) {
          return nextAuctionId++;
        }
        uint256[1000] private ______gap;
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      pragma abicoder v2; // solhint-disable-line
      import "@openzeppelin/contracts-upgradeable/math/SafeMathUpgradeable.sol";
      import "@openzeppelin/contracts-upgradeable/token/ERC721/IERC721Upgradeable.sol";
      import "@openzeppelin/contracts-upgradeable/utils/ReentrancyGuardUpgradeable.sol";
      import "./Constants.sol";
      import "./NFTMarketCore.sol";
      import "./NFTMarketFees.sol";
      import "./SendValueWithFallbackWithdraw.sol";
      import "./NFTMarketAuction.sol";
      import "./roles/FoundationAdminRole.sol";
      import "./AccountMigration.sol";
      /**
       * @notice Manages a reserve price auction for NFTs.
       */
      abstract contract NFTMarketReserveAuction is
        Constants,
        FoundationAdminRole,
        AccountMigration,
        NFTMarketCore,
        ReentrancyGuardUpgradeable,
        SendValueWithFallbackWithdraw,
        NFTMarketFees,
        NFTMarketAuction
      {
        using SafeMathUpgradeable for uint256;
        struct ReserveAuction {
          address nftContract;
          uint256 tokenId;
          address payable seller;
          uint256 duration;
          uint256 extensionDuration;
          uint256 endTime;
          address payable bidder;
          uint256 amount;
        }
        mapping(address => mapping(uint256 => uint256)) private nftContractToTokenIdToAuctionId;
        mapping(uint256 => ReserveAuction) private auctionIdToAuction;
        uint256 private _minPercentIncrementInBasisPoints;
        // This variable was used in an older version of the contract, left here as a gap to ensure upgrade compatibility
        uint256 private ______gap_was_maxBidIncrementRequirement;
        uint256 private _duration;
        // These variables were used in an older version of the contract, left here as gaps to ensure upgrade compatibility
        uint256 private ______gap_was_extensionDuration;
        uint256 private ______gap_was_goLiveDate;
        // Cap the max duration so that overflows will not occur
        uint256 private constant MAX_MAX_DURATION = 1000 days;
        uint256 private constant EXTENSION_DURATION = 15 minutes;
        event ReserveAuctionConfigUpdated(
          uint256 minPercentIncrementInBasisPoints,
          uint256 maxBidIncrementRequirement,
          uint256 duration,
          uint256 extensionDuration,
          uint256 goLiveDate
        );
        event ReserveAuctionCreated(
          address indexed seller,
          address indexed nftContract,
          uint256 indexed tokenId,
          uint256 duration,
          uint256 extensionDuration,
          uint256 reservePrice,
          uint256 auctionId
        );
        event ReserveAuctionUpdated(uint256 indexed auctionId, uint256 reservePrice);
        event ReserveAuctionCanceled(uint256 indexed auctionId);
        event ReserveAuctionBidPlaced(uint256 indexed auctionId, address indexed bidder, uint256 amount, uint256 endTime);
        event ReserveAuctionFinalized(
          uint256 indexed auctionId,
          address indexed seller,
          address indexed bidder,
          uint256 f8nFee,
          uint256 creatorFee,
          uint256 ownerRev
        );
        event ReserveAuctionCanceledByAdmin(uint256 indexed auctionId, string reason);
        event ReserveAuctionSellerMigrated(
          uint256 indexed auctionId,
          address indexed originalSellerAddress,
          address indexed newSellerAddress
        );
        modifier onlyValidAuctionConfig(uint256 reservePrice) {
          require(reservePrice > 0, "NFTMarketReserveAuction: Reserve price must be at least 1 wei");
          _;
        }
        /**
         * @notice Returns auction details for a given auctionId.
         */
        function getReserveAuction(uint256 auctionId) public view returns (ReserveAuction memory) {
          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.
         */
        function getReserveAuctionIdFor(address nftContract, uint256 tokenId) public view returns (uint256) {
          return nftContractToTokenIdToAuctionId[nftContract][tokenId];
        }
        /**
         * @dev Returns the seller that put a given NFT into escrow,
         * or bubbles the call up to check the current owner if the NFT is not currently in escrow.
         */
        function _getSellerFor(address nftContract, uint256 tokenId)
          internal
          view
          virtual
          override
          returns (address payable seller)
        {
          seller = auctionIdToAuction[nftContractToTokenIdToAuctionId[nftContract][tokenId]].seller;
          if (seller == address(0)) {
            return super._getSellerFor(nftContract, tokenId);
          }
        }
        /**
         * @notice Returns the current configuration for reserve auctions.
         */
        function getReserveAuctionConfig() public view returns (uint256 minPercentIncrementInBasisPoints, uint256 duration) {
          minPercentIncrementInBasisPoints = _minPercentIncrementInBasisPoints;
          duration = _duration;
        }
        function _initializeNFTMarketReserveAuction() internal {
          _duration = 24 hours; // A sensible default value
        }
        function _updateReserveAuctionConfig(uint256 minPercentIncrementInBasisPoints, uint256 duration) internal {
          require(minPercentIncrementInBasisPoints <= BASIS_POINTS, "NFTMarketReserveAuction: Min increment must be <= 100%");
          // Cap the max duration so that overflows will not occur
          require(duration <= MAX_MAX_DURATION, "NFTMarketReserveAuction: Duration must be <= 1000 days");
          require(duration >= EXTENSION_DURATION, "NFTMarketReserveAuction: Duration must be >= EXTENSION_DURATION");
          _minPercentIncrementInBasisPoints = minPercentIncrementInBasisPoints;
          _duration = duration;
          // We continue to emit unused configuration variables to simplify the subgraph integration.
          emit ReserveAuctionConfigUpdated(minPercentIncrementInBasisPoints, 0, duration, EXTENSION_DURATION, 0);
        }
        /**
         * @notice Creates an auction for the given NFT.
         * The NFT is held in escrow until the auction is finalized or canceled.
         */
        function createReserveAuction(
          address nftContract,
          uint256 tokenId,
          uint256 reservePrice
        ) public onlyValidAuctionConfig(reservePrice) nonReentrant {
          // If an auction is already in progress then the NFT would be in escrow and the modifier would have failed
          uint256 auctionId = _getNextAndIncrementAuctionId();
          nftContractToTokenIdToAuctionId[nftContract][tokenId] = auctionId;
          auctionIdToAuction[auctionId] = ReserveAuction(
            nftContract,
            tokenId,
            msg.sender,
            _duration,
            EXTENSION_DURATION,
            0, // endTime is only known once the reserve price is met
            address(0), // bidder is only known once a bid has been placed
            reservePrice
          );
          IERC721Upgradeable(nftContract).transferFrom(msg.sender, address(this), tokenId);
          emit ReserveAuctionCreated(
            msg.sender,
            nftContract,
            tokenId,
            _duration,
            EXTENSION_DURATION,
            reservePrice,
            auctionId
          );
        }
        /**
         * @notice If an auction has been created but has not yet received bids, the configuration
         * such as the reservePrice may be changed by the seller.
         */
        function updateReserveAuction(uint256 auctionId, uint256 reservePrice) public onlyValidAuctionConfig(reservePrice) {
          ReserveAuction storage auction = auctionIdToAuction[auctionId];
          require(auction.seller == msg.sender, "NFTMarketReserveAuction: Not your auction");
          require(auction.endTime == 0, "NFTMarketReserveAuction: Auction in progress");
          auction.amount = reservePrice;
          emit ReserveAuctionUpdated(auctionId, reservePrice);
        }
        /**
         * @notice If an auction has been created but has not yet received bids, it may be canceled by the seller.
         * The NFT is returned to the seller from escrow.
         */
        function cancelReserveAuction(uint256 auctionId) public nonReentrant {
          ReserveAuction memory auction = auctionIdToAuction[auctionId];
          require(auction.seller == msg.sender, "NFTMarketReserveAuction: Not your auction");
          require(auction.endTime == 0, "NFTMarketReserveAuction: Auction in progress");
          delete nftContractToTokenIdToAuctionId[auction.nftContract][auction.tokenId];
          delete auctionIdToAuction[auctionId];
          IERC721Upgradeable(auction.nftContract).transferFrom(address(this), auction.seller, auction.tokenId);
          emit ReserveAuctionCanceled(auctionId);
        }
        /**
         * @notice 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.
         */
        function placeBid(uint256 auctionId) public payable nonReentrant {
          ReserveAuction storage auction = auctionIdToAuction[auctionId];
          require(auction.amount != 0, "NFTMarketReserveAuction: Auction not found");
          if (auction.endTime == 0) {
            // If this is the first bid, ensure it's >= the reserve price
            require(auction.amount <= msg.value, "NFTMarketReserveAuction: Bid must be at least the reserve price");
          } else {
            // If this bid outbids another, confirm that the bid is at least x% greater than the last
            require(auction.endTime >= block.timestamp, "NFTMarketReserveAuction: Auction is over");
            require(auction.bidder != msg.sender, "NFTMarketReserveAuction: You already have an outstanding bid");
            uint256 minAmount = _getMinBidAmountForReserveAuction(auction.amount);
            require(msg.value >= minAmount, "NFTMarketReserveAuction: Bid amount too low");
          }
          if (auction.endTime == 0) {
            auction.amount = msg.value;
            auction.bidder = msg.sender;
            // On the first bid, the endTime is now + duration
            auction.endTime = block.timestamp + auction.duration;
          } else {
            // Cache and update bidder state before a possible reentrancy (via the value transfer)
            uint256 originalAmount = auction.amount;
            address payable originalBidder = auction.bidder;
            auction.amount = msg.value;
            auction.bidder = msg.sender;
            // When a bid outbids another, check to see if a time extension should apply.
            if (auction.endTime - block.timestamp < auction.extensionDuration) {
              auction.endTime = block.timestamp + auction.extensionDuration;
            }
            // Refund the previous bidder
            _sendValueWithFallbackWithdrawWithLowGasLimit(originalBidder, originalAmount);
          }
          emit ReserveAuctionBidPlaced(auctionId, msg.sender, msg.value, auction.endTime);
        }
        /**
         * @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 funds.
         */
        function finalizeReserveAuction(uint256 auctionId) public nonReentrant {
          ReserveAuction memory auction = auctionIdToAuction[auctionId];
          require(auction.endTime > 0, "NFTMarketReserveAuction: Auction was already settled");
          require(auction.endTime < block.timestamp, "NFTMarketReserveAuction: Auction still in progress");
          delete nftContractToTokenIdToAuctionId[auction.nftContract][auction.tokenId];
          delete auctionIdToAuction[auctionId];
          IERC721Upgradeable(auction.nftContract).transferFrom(address(this), auction.bidder, auction.tokenId);
          (uint256 f8nFee, uint256 creatorFee, uint256 ownerRev) = _distributeFunds(
            auction.nftContract,
            auction.tokenId,
            auction.seller,
            auction.amount
          );
          emit ReserveAuctionFinalized(auctionId, auction.seller, auction.bidder, f8nFee, creatorFee, ownerRev);
        }
        /**
         * @notice Returns the minimum amount a bidder must spend to participate in an auction.
         */
        function getMinBidAmount(uint256 auctionId) public view returns (uint256) {
          ReserveAuction storage auction = auctionIdToAuction[auctionId];
          if (auction.endTime == 0) {
            return auction.amount;
          }
          return _getMinBidAmountForReserveAuction(auction.amount);
        }
        /**
         * @dev Determines the minimum bid amount when outbidding another user.
         */
        function _getMinBidAmountForReserveAuction(uint256 currentBidAmount) private view returns (uint256) {
          uint256 minIncrement = currentBidAmount.mul(_minPercentIncrementInBasisPoints) / BASIS_POINTS;
          if (minIncrement == 0) {
            // The next bid must be at least 1 wei greater than the current.
            return currentBidAmount.add(1);
          }
          return minIncrement.add(currentBidAmount);
        }
        /**
         * @notice Allows Foundation to cancel an auction, refunding the bidder and returning the NFT to the seller.
         * This should only be used for extreme cases such as DMCA takedown requests. The reason should always be provided.
         */
        function adminCancelReserveAuction(uint256 auctionId, string memory reason) public onlyFoundationAdmin {
          require(bytes(reason).length > 0, "NFTMarketReserveAuction: Include a reason for this cancellation");
          ReserveAuction memory auction = auctionIdToAuction[auctionId];
          require(auction.amount > 0, "NFTMarketReserveAuction: Auction not found");
          delete nftContractToTokenIdToAuctionId[auction.nftContract][auction.tokenId];
          delete auctionIdToAuction[auctionId];
          IERC721Upgradeable(auction.nftContract).transferFrom(address(this), auction.seller, auction.tokenId);
          if (auction.bidder != address(0)) {
            _sendValueWithFallbackWithdrawWithMediumGasLimit(auction.bidder, auction.amount);
          }
          emit ReserveAuctionCanceledByAdmin(auctionId, reason);
        }
        /**
         * @notice Allows an NFT owner and Foundation to work together in order to update the seller
         * for auctions they have listed to a new account.
         * @param signature Message `I authorize Foundation to migrate my account to ${newAccount.address.toLowerCase()}`
         * signed by the original account.
         * @dev This will gracefully skip any auctions that have already been finalized.
         */
        function adminAccountMigration(
          uint256[] calldata listedAuctionIds,
          address originalAddress,
          address payable newAddress,
          bytes calldata signature
        ) public onlyAuthorizedAccountMigration(originalAddress, newAddress, signature) {
          for (uint256 i = 0; i < listedAuctionIds.length; i++) {
            uint256 auctionId = listedAuctionIds[i];
            ReserveAuction storage auction = auctionIdToAuction[auctionId];
            // The seller would be 0 if it was finalized before this call
            if (auction.seller != address(0)) {
              require(auction.seller == originalAddress, "NFTMarketReserveAuction: Auction not created by that address");
              auction.seller = newAddress;
              emit ReserveAuctionSellerMigrated(auctionId, originalAddress, newAddress);
            }
          }
        }
        uint256[1000] private ______gap;
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      import "@openzeppelin/contracts/cryptography/ECDSA.sol";
      import "@openzeppelin/contracts/utils/Address.sol";
      import "@openzeppelin/contracts/utils/Strings.sol";
      import "./roles/FoundationOperatorRole.sol";
      import "../interfaces/IERC1271.sol";
      /**
       * @notice Checks for a valid signature authorizing the migration of an account to a new address.
       * @dev This is shared by both the FNDNFT721 and FNDNFTMarket, and the same signature authorizes both.
       */
      abstract contract AccountMigration is FoundationOperatorRole {
        // From https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.1.0/contracts/utils/cryptography
        function _isValidSignatureNow(
          address signer,
          bytes32 hash,
          bytes memory signature
        ) private view returns (bool) {
          if (Address.isContract(signer)) {
            try IERC1271(signer).isValidSignature(hash, signature) returns (bytes4 magicValue) {
              return magicValue == IERC1271(signer).isValidSignature.selector;
            } catch {
              return false;
            }
          } else {
            return ECDSA.recover(hash, signature) == signer;
          }
        }
        // From https://ethereum.stackexchange.com/questions/8346/convert-address-to-string
        function _toAsciiString(address x) private pure returns (string memory) {
          bytes memory s = new bytes(42);
          s[0] = "0";
          s[1] = "x";
          for (uint256 i = 0; i < 20; i++) {
            bytes1 b = bytes1(uint8(uint256(uint160(x)) / (2**(8 * (19 - i)))));
            bytes1 hi = bytes1(uint8(b) / 16);
            bytes1 lo = bytes1(uint8(b) - 16 * uint8(hi));
            s[2 * i + 2] = _char(hi);
            s[2 * i + 3] = _char(lo);
          }
          return string(s);
        }
        function _char(bytes1 b) private pure returns (bytes1 c) {
          if (uint8(b) < 10) return bytes1(uint8(b) + 0x30);
          else return bytes1(uint8(b) + 0x57);
        }
        // From https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.1.0/contracts/utils/cryptography/ECDSA.sol
        // Modified to accept messages (instead of the message hash)
        function _toEthSignedMessage(bytes memory message) private pure returns (bytes32) {
          return keccak256(abi.encodePacked("\\x19Ethereum Signed Message:\
      ", Strings.toString(message.length), message));
        }
        /**
         * @dev Confirms the msg.sender is a Foundation operator and that the signature provided is valid.
         * @param signature Message `I authorize Foundation to migrate my account to ${newAccount.address.toLowerCase()}`
         * signed by the original account.
         */
        modifier onlyAuthorizedAccountMigration(
          address originalAddress,
          address newAddress,
          bytes memory signature
        ) {
          require(_isFoundationOperator(), "AccountMigration: Caller is not an operator");
          require(originalAddress != newAddress, "AccountMigration: Cannot migrate to the same account");
          bytes32 hash = _toEthSignedMessage(
            abi.encodePacked("I authorize Foundation to migrate my account to ", _toAsciiString(newAddress))
          );
          require(
            _isValidSignatureNow(originalAddress, hash, signature),
            "AccountMigration: Signature must be from the original account"
          );
          _;
        }
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      import "@openzeppelin/contracts-upgradeable/token/ERC721/IERC721Upgradeable.sol";
      import "./NFTMarketFees.sol";
      /**
       * @notice Adds support for a private sale of an NFT directly between two parties.
       */
      abstract contract NFTMarketPrivateSale is NFTMarketFees {
        /**
         * @dev This name is used in the EIP-712 domain.
         * If multiple classes use EIP-712 signatures in the future this can move to the shared constants file.
         */
        string private constant NAME = "FNDNFTMarket";
        /**
         * @dev This is a hash of the method signature used in the EIP-712 signature for private sales.
         */
        bytes32 private constant BUY_FROM_PRIVATE_SALE_TYPEHASH =
          keccak256("BuyFromPrivateSale(address nftContract,uint256 tokenId,address buyer,uint256 price,uint256 deadline)");
        /**
         * @dev This is the domain used in EIP-712 signatures.
         * It is not a constant so that the chainId can be determined dynamically.
         * If multiple classes use EIP-712 signatures in the future this can move to a shared file.
         */
        bytes32 private DOMAIN_SEPARATOR;
        event PrivateSaleFinalized(
          address indexed nftContract,
          uint256 indexed tokenId,
          address indexed seller,
          address buyer,
          uint256 f8nFee,
          uint256 creatorFee,
          uint256 ownerRev,
          uint256 deadline
        );
        /**
         * @dev This function must be called at least once before signatures will work as expected.
         * It's okay to call this function many times. Subsequent calls will have no impact.
         */
        function _reinitialize() internal {
          uint256 chainId;
          // solhint-disable-next-line no-inline-assembly
          assembly {
            chainId := chainid()
          }
          DOMAIN_SEPARATOR = keccak256(
            abi.encode(
              keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
              keccak256(bytes(NAME)),
              keccak256(bytes("1")),
              chainId,
              address(this)
            )
          );
        }
        /**
         * @notice Allow two parties to execute a private sale.
         * @dev The seller signs a message approving the sale, and then the buyer calls this function
         * with the msg.value equal to the agreed upon price.
         * The sale is executed in this single on-chain call including the transfer of funds and the NFT.
         */
        function buyFromPrivateSale(
          IERC721Upgradeable nftContract,
          uint256 tokenId,
          uint256 deadline,
          uint8 v,
          bytes32 r,
          bytes32 s
        ) public payable {
          // The signed message from the seller is only valid for a limited time.
          require(deadline >= block.timestamp, "NFTMarketPrivateSale: EXPIRED");
          // The seller must have the NFT in their wallet when this function is called.
          address payable seller = payable(nftContract.ownerOf(tokenId));
          // Scoping this block to avoid a stack too deep error
          {
            bytes32 digest = keccak256(
              abi.encodePacked(
                "\\x19\\x01",
                DOMAIN_SEPARATOR,
                keccak256(abi.encode(BUY_FROM_PRIVATE_SALE_TYPEHASH, nftContract, tokenId, msg.sender, msg.value, deadline))
              )
            );
            // Revert if the signature is invalid, the terms are not as expected, or if the seller transferred the NFT.
            require(ecrecover(digest, v, r, s) == seller, "NFTMarketPrivateSale: INVALID_SIGNATURE");
          }
          // This will revert if the seller has not given the market contract approval.
          nftContract.transferFrom(seller, msg.sender, tokenId);
          // Pay the seller, creator, and Foundation as appropriate.
          (uint256 f8nFee, uint256 creatorFee, uint256 ownerRev) = _distributeFunds(
            address(nftContract),
            tokenId,
            seller,
            msg.value
          );
          emit PrivateSaleFinalized(
            address(nftContract),
            tokenId,
            seller,
            msg.sender,
            f8nFee,
            creatorFee,
            ownerRev,
            deadline
          );
        }
        uint256[1000] private ______gap;
      }
      // 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));
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.7.0;
      /**
       * @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);
                  }
              }
          }
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      /**
       * @notice Interface for AdminRole which wraps the default admin role from
       * OpenZeppelin's AccessControl for easy integration.
       */
      interface IAdminRole {
        function isAdmin(address account) external view returns (bool);
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      /**
       * @notice Interface for OperatorRole which wraps a role from
       * OpenZeppelin's AccessControl for easy integration.
       */
      interface IOperatorRole {
        function isOperator(address account) external view returns (bool);
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.7.0;
      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;
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.7.0;
      /**
       * @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);
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.7.0;
      /**
       * @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;
          }
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      // solhint-disable
      pragma solidity ^0.7.0;
      interface IFNDNFT721 {
        function tokenCreator(uint256 tokenId) external view returns (address payable);
        function getTokenCreatorPaymentAddress(uint256 tokenId) external view returns (address payable);
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      interface ITokenCreatorPaymentAddress {
        function getTokenCreatorPaymentAddress(uint256 tokenId)
          external
          view
          returns (address payable tokenCreatorPaymentAddress);
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      interface ITokenCreator {
        function tokenCreator(uint256 tokenId) external view returns (address payable);
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      interface IGetRoyalties {
        function getRoyalties(uint256 tokenId)
          external
          view
          returns (address payable[] memory recipients, uint256[] memory feesInBasisPoints);
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      /**
       * @notice An interface for communicating fees to 3rd party marketplaces.
       * @dev Originally implemented in mainnet contract 0x44d6e8933f8271abcf253c72f9ed7e0e4c0323b3
       */
      interface IHasSecondarySaleFees {
        function getFeeRecipients(uint256 id) external view returns (address payable[] memory);
        function getFeeBps(uint256 id) external view returns (uint256[] memory);
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.7.0;
      interface IOwnable {
        /**
         * @dev Returns the address of the current owner.
         */
        function owner() external view returns (address);
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.7.0;
      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 () {
              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;
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.7.0;
      /**
       * From https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.2.0/contracts/utils/introspection/ERC165.sol
       * Modified to support Solidity 0.7 and allow checking multiple interfaces w/o checking general 165 support.
       */
      import "./IERC165.sol";
      /**
       * @dev Library used to query support of an interface declared via {IERC165}.
       *
       * Note that these functions return the actual result of the query: they do not
       * `revert` if an interface is not supported. It is up to the caller to decide
       * what to do in these cases.
       */
      library ERC165Checker {
        // As per the EIP-165 spec, no interface should ever match 0xffffffff
        bytes4 private constant _INTERFACE_ID_INVALID = 0xffffffff;
        /**
         * @dev Returns true if `account` supports the {IERC165} interface,
         */
        function supportsERC165(address account) internal view returns (bool) {
          // Any contract that implements ERC165 must explicitly indicate support of
          // InterfaceId_ERC165 and explicitly indicate non-support of InterfaceId_Invalid
          return
            supportsERC165Interface(account, type(IERC165).interfaceId) &&
            !supportsERC165Interface(account, _INTERFACE_ID_INVALID);
        }
        /**
         * @dev Returns true if `account` supports the interface defined by
         * `interfaceId`. Support for {IERC165} itself is queried automatically.
         *
         * See {IERC165-supportsInterface}.
         */
        function supportsInterface(address account, bytes4 interfaceId) internal view returns (bool) {
          // query support of both ERC165 as per the spec and support of _interfaceId
          return supportsERC165(account) && supportsERC165Interface(account, interfaceId);
        }
        /**
         * @dev Returns a boolean array where each value corresponds to the
         * interfaces passed in and whether they're supported or not. This allows
         * you to batch check interfaces for a contract where your expectation
         * is that some interfaces may not be supported.
         *
         * See {IERC165-supportsInterface}.
         *
         * _Available since v3.4._
         */
        function getSupportedInterfaces(address account, bytes4[] memory interfaceIds) internal view returns (bool[] memory) {
          // an array of booleans corresponding to interfaceIds and whether they're supported or not
          bool[] memory interfaceIdsSupported = new bool[](interfaceIds.length);
          // query support of ERC165 itself
          if (supportsERC165(account)) {
            // query support of each interface in interfaceIds
            for (uint256 i = 0; i < interfaceIds.length; i++) {
              interfaceIdsSupported[i] = supportsERC165Interface(account, interfaceIds[i]);
            }
          }
          return interfaceIdsSupported;
        }
        /**
         * @dev Returns true if `account` supports all the interfaces defined in
         * `interfaceIds`. Support for {IERC165} itself is queried automatically.
         *
         * Batch-querying can lead to gas savings by skipping repeated checks for
         * {IERC165} support.
         *
         * See {IERC165-supportsInterface}.
         */
        function supportsAllInterfaces(address account, bytes4[] memory interfaceIds) internal view returns (bool) {
          // query support of ERC165 itself
          if (!supportsERC165(account)) {
            return false;
          }
          // query support of each interface in _interfaceIds
          for (uint256 i = 0; i < interfaceIds.length; i++) {
            if (!supportsERC165Interface(account, interfaceIds[i])) {
              return false;
            }
          }
          // all interfaces supported
          return true;
        }
        /**
         * @notice Query if a contract implements an interface, does not check ERC165 support
         * @param account The address of the contract to query for support of an interface
         * @param interfaceId The interface identifier, as specified in ERC-165
         * @return true if the contract at account indicates support of the interface with
         * identifier interfaceId, false otherwise
         * @dev Assumes that account contains a contract that supports ERC165, otherwise
         * the behavior of this method is undefined. This precondition can be checked
         * with {supportsERC165}.
         * Interface identification is specified in ERC-165.
         */
        function supportsERC165Interface(address account, bytes4 interfaceId) internal view returns (bool) {
          bytes memory encodedParams = abi.encodeWithSelector(IERC165(account).supportsInterface.selector, interfaceId);
          (bool success, bytes memory result) = account.staticcall{ gas: 30000 }(encodedParams);
          if (result.length < 32) return false;
          return success && abi.decode(result, (bool));
        }
      }
      // SPDX-License-Identifier: MIT OR Apache-2.0
      pragma solidity ^0.7.0;
      /**
       * @dev Constant values shared across mixins.
       */
      abstract contract Constants {
        uint256 internal constant BASIS_POINTS = 10000;
        uint256 internal constant READ_ONLY_GAS_LIMIT = 40000;
        /**
         * @dev Support up to 5 royalty recipients. A cap is required to ensure gas costs are not too high
         * when an auction is finalized.
         */
        uint256 internal constant MAX_CREATOR_INDEX = 4;
      }
      // 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;
          }
      }
      // SPDX-License-Identifier: MIT
      /**
       * From https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.2.0/contracts/utils/introspection/IERC165.sol
       * Modified to support Solidity 0.7
       */
      pragma solidity ^0.7.0;
      /**
       * @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);
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.7.0;
      /**
       * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
       *
       * These functions can be used to verify that a message was signed by the holder
       * of the private keys of a given address.
       */
      library ECDSA {
          /**
           * @dev Returns the address that signed a hashed message (`hash`) with
           * `signature`. This address can then be used for verification purposes.
           *
           * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
           * this function rejects them by requiring the `s` value to be in the lower
           * half order, and the `v` value to be either 27 or 28.
           *
           * IMPORTANT: `hash` _must_ be the result of a hash operation for the
           * verification to be secure: it is possible to craft signatures that
           * recover to arbitrary addresses for non-hashed data. A safe way to ensure
           * this is by receiving a hash of the original message (which may otherwise
           * be too long), and then calling {toEthSignedMessageHash} on it.
           */
          function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
              // Check the signature length
              if (signature.length != 65) {
                  revert("ECDSA: invalid signature length");
              }
              // Divide the signature in r, s and v variables
              bytes32 r;
              bytes32 s;
              uint8 v;
              // ecrecover takes the signature parameters, and the only way to get them
              // currently is to use assembly.
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  r := mload(add(signature, 0x20))
                  s := mload(add(signature, 0x40))
                  v := byte(0, mload(add(signature, 0x60)))
              }
              return recover(hash, v, r, s);
          }
          /**
           * @dev Overload of {ECDSA-recover-bytes32-bytes-} that receives the `v`,
           * `r` and `s` signature fields separately.
           */
          function recover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) internal pure returns (address) {
              // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
              // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
              // the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
              // signatures from current libraries generate a unique signature with an s-value in the lower half order.
              //
              // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
              // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
              // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
              // these malleable signatures as well.
              require(uint256(s) <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0, "ECDSA: invalid signature 's' value");
              require(v == 27 || v == 28, "ECDSA: invalid signature 'v' value");
              // If the signature is valid (and not malleable), return the signer address
              address signer = ecrecover(hash, v, r, s);
              require(signer != address(0), "ECDSA: invalid signature");
              return signer;
          }
          /**
           * @dev Returns an Ethereum Signed Message, created from a `hash`. This
           * replicates the behavior of the
           * https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_sign[`eth_sign`]
           * JSON-RPC method.
           *
           * See {recover}.
           */
          function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
              // 32 is the length in bytes of hash,
              // enforced by the type signature above
              return keccak256(abi.encodePacked("\\x19Ethereum Signed Message:\
      32", hash));
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.7.0;
      /**
       * @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);
                  }
              }
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.7.0;
      /**
       * @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);
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.7.0;
      /**
       * @dev Interface of the ERC1271 standard signature validation method for
       * contracts as defined in https://eips.ethereum.org/EIPS/eip-1271[ERC-1271].
       *
       * from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.1.0/contracts/interfaces/IERC1271.sol
       */
      interface IERC1271 {
        /**
         * @dev Should return whether the signature provided is valid for the provided data
         * @param hash      Hash of the data to be signed
         * @param signature Signature byte array associated with _data
         */
        function isValidSignature(bytes32 hash, bytes memory signature) external view returns (bytes4 magicValue);
      }