// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (proxy/ERC1967/ERC1967Proxy.sol)
pragma solidity 0.8.17;
// OpenZeppelin Contracts v4.4.1 (proxy/Proxy.sol)
/**
 * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
 * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
 * be specified by overriding the virtual {_implementation} function.
 *
 * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
 * different contract through the {_delegate} function.
 *
 * The success and return data of the delegated call will be returned back to the caller of the proxy.
 */
abstract contract Proxy {
    /**
     * @dev Delegates the current call to `implementation`.
     *
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _delegate(address implementation) internal virtual {
        assembly {
            // Copy msg.data. We take full control of memory in this inline assembly
            // block because it will not return to Solidity code. We overwrite the
            // Solidity scratch pad at memory position 0.
            calldatacopy(0, 0, calldatasize())
            // Call the implementation.
            // out and outsize are 0 because we don't know the size yet.
            let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
            // Copy the returned data.
            returndatacopy(0, 0, returndatasize())
            switch result
            // delegatecall returns 0 on error.
            case 0 {
                revert(0, returndatasize())
            }
            default {
                return(0, returndatasize())
            }
        }
    }
    /**
     * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
     * and {_fallback} should delegate.
     */
    function _implementation() internal view virtual returns (address);
    /**
     * @dev Delegates the current call to the address returned by `_implementation()`.
     *
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _fallback() internal virtual {
        _beforeFallback();
        _delegate(_implementation());
    }
    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
     * function in the contract matches the call data.
     */
    fallback() external payable virtual {
        _fallback();
    }
    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
     * is empty.
     */
    receive() external payable virtual {
        _fallback();
    }
    /**
     * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
     * call, or as part of the Solidity `fallback` or `receive` functions.
     *
     * If overriden should call `super._beforeFallback()`.
     */
    function _beforeFallback() internal virtual {}
}
// OpenZeppelin Contracts v4.4.1 (proxy/ERC1967/ERC1967Upgrade.sol)
/**
 * @dev This abstract contract provides getters and event emitting update functions for
 * https://eips.ethereum.org/EIPS/eip-1967[EIP1967] slots.
 *
 * _Available since v4.1._
 *
 * @custom:oz-upgrades-unsafe-allow delegatecall
 */
abstract contract ERC1967Upgrade {
    // This is the keccak-256 hash of "eip1967.proxy.rollback" subtracted by 1
    bytes32 private constant _ROLLBACK_SLOT = 0x4910fdfa16fed3260ed0e7147f7cc6da11a60208b5b9406d12a635614ffd9143;
    /**
     * @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 Emitted when the implementation is upgraded.
     */
    event Upgraded(address indexed implementation);
    /**
     * @dev Returns the current implementation address.
     */
    function _getImplementation() internal view returns (address) {
        return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
    }
    /**
     * @dev Stores a new address in the EIP1967 implementation slot.
     */
    function _setImplementation(address newImplementation) private {
        require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
        StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
    }
    /**
     * @dev Perform implementation upgrade
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeTo(address newImplementation) internal {
        _setImplementation(newImplementation);
        emit Upgraded(newImplementation);
    }
    /**
     * @dev Perform implementation upgrade with additional setup call.
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeToAndCall(
        address newImplementation,
        bytes memory data,
        bool forceCall
    ) internal {
        _upgradeTo(newImplementation);
        if (data.length > 0 || forceCall) {
            Address.functionDelegateCall(newImplementation, data);
        }
    }
    /**
     * @dev Perform implementation upgrade with security checks for UUPS proxies, and additional setup call.
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeToAndCallSecure(
        address newImplementation,
        bytes memory data,
        bool forceCall
    ) internal {
        address oldImplementation = _getImplementation();
        // Initial upgrade and setup call
        _setImplementation(newImplementation);
        if (data.length > 0 || forceCall) {
            Address.functionDelegateCall(newImplementation, data);
        }
        // Perform rollback test if not already in progress
        StorageSlot.BooleanSlot storage rollbackTesting = StorageSlot.getBooleanSlot(_ROLLBACK_SLOT);
        if (!rollbackTesting.value) {
            // Trigger rollback using upgradeTo from the new implementation
            rollbackTesting.value = true;
            Address.functionDelegateCall(
                newImplementation,
                abi.encodeWithSignature("upgradeTo(address)", oldImplementation)
            );
            rollbackTesting.value = false;
            // Check rollback was effective
            require(oldImplementation == _getImplementation(), "ERC1967Upgrade: upgrade breaks further upgrades");
            // Finally reset to the new implementation and log the upgrade
            _upgradeTo(newImplementation);
        }
    }
    /**
     * @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 Emitted when the admin account has changed.
     */
    event AdminChanged(address previousAdmin, address newAdmin);
    /**
     * @dev Returns the current admin.
     */
    function _getAdmin() internal view returns (address) {
        return StorageSlot.getAddressSlot(_ADMIN_SLOT).value;
    }
    /**
     * @dev Stores a new address in the EIP1967 admin slot.
     */
    function _setAdmin(address newAdmin) private {
        require(newAdmin != address(0), "ERC1967: new admin is the zero address");
        StorageSlot.getAddressSlot(_ADMIN_SLOT).value = newAdmin;
    }
    /**
     * @dev Changes the admin of the proxy.
     *
     * Emits an {AdminChanged} event.
     */
    function _changeAdmin(address newAdmin) internal {
        emit AdminChanged(_getAdmin(), newAdmin);
        _setAdmin(newAdmin);
    }
    /**
     * @dev The storage slot of the UpgradeableBeacon contract which defines the implementation for this proxy.
     * This is bytes32(uint256(keccak256('eip1967.proxy.beacon')) - 1)) and is validated in the constructor.
     */
    bytes32 internal constant _BEACON_SLOT = 0xa3f0ad74e5423aebfd80d3ef4346578335a9a72aeaee59ff6cb3582b35133d50;
    /**
     * @dev Emitted when the beacon is upgraded.
     */
    event BeaconUpgraded(address indexed beacon);
    /**
     * @dev Returns the current beacon.
     */
    function _getBeacon() internal view returns (address) {
        return StorageSlot.getAddressSlot(_BEACON_SLOT).value;
    }
    /**
     * @dev Stores a new beacon in the EIP1967 beacon slot.
     */
    function _setBeacon(address newBeacon) private {
        require(Address.isContract(newBeacon), "ERC1967: new beacon is not a contract");
        require(
            Address.isContract(IBeacon(newBeacon).implementation()),
            "ERC1967: beacon implementation is not a contract"
        );
        StorageSlot.getAddressSlot(_BEACON_SLOT).value = newBeacon;
    }
    /**
     * @dev Perform beacon upgrade with additional setup call. Note: This upgrades the address of the beacon, it does
     * not upgrade the implementation contained in the beacon (see {UpgradeableBeacon-_setImplementation} for that).
     *
     * Emits a {BeaconUpgraded} event.
     */
    function _upgradeBeaconToAndCall(
        address newBeacon,
        bytes memory data,
        bool forceCall
    ) internal {
        _setBeacon(newBeacon);
        emit BeaconUpgraded(newBeacon);
        if (data.length > 0 || forceCall) {
            Address.functionDelegateCall(IBeacon(newBeacon).implementation(), data);
        }
    }
}
/**
 * @dev This contract implements an upgradeable proxy. It is upgradeable because calls are delegated to an
 * implementation address that can be changed. This address is stored in storage in the location specified by
 * https://eips.ethereum.org/EIPS/eip-1967[EIP1967], so that it doesn't conflict with the storage layout of the
 * implementation behind the proxy.
 */
contract ERC1967Proxy is Proxy, ERC1967Upgrade {
    /**
     * @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
     *
     * If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
     * function call, and allows initializating the storage of the proxy like a Solidity constructor.
     */
    constructor(address _logic, bytes memory _data) payable {
        assert(_IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
        _upgradeToAndCall(_logic, _data, false);
    }
    /**
     * @dev Returns the current implementation address.
     */
    function _implementation() internal view virtual override returns (address impl) {
        return ERC1967Upgrade._getImplementation();
    }
}
// OpenZeppelin Contracts v4.4.1 (proxy/beacon/IBeacon.sol)
/**
 * @dev This is the interface that {BeaconProxy} expects of its beacon.
 */
interface IBeacon {
    /**
     * @dev Must return an address that can be used as a delegate call target.
     *
     * {BeaconProxy} will check that this address is a contract.
     */
    function implementation() external view returns (address);
}
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)
pragma solidity ^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;
        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");
        (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");
        (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");
        (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");
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal 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
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}
// OpenZeppelin Contracts v4.4.1 (utils/StorageSlot.sol)
/**
 * @dev Library for reading and writing primitive types to specific storage slots.
 *
 * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
 * This library helps with reading and writing to such slots without the need for inline assembly.
 *
 * The functions in this library return Slot structs that contain a `value` member that can be used to read or write.
 *
 * Example usage to set ERC1967 implementation slot:
 * ```
 * contract ERC1967 {
 *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
 *
 *     function _getImplementation() internal view returns (address) {
 *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
 *     }
 *
 *     function _setImplementation(address newImplementation) internal {
 *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
 *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
 *     }
 * }
 * ```
 *
 * _Available since v4.1 for `address`, `bool`, `bytes32`, and `uint256`._
 */
library StorageSlot {
    struct AddressSlot {
        address value;
    }
    struct BooleanSlot {
        bool value;
    }
    struct Bytes32Slot {
        bytes32 value;
    }
    struct Uint256Slot {
        uint256 value;
    }
    /**
     * @dev Returns an `AddressSlot` with member `value` located at `slot`.
     */
    function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
        assembly {
            r.slot := slot
        }
    }
    /**
     * @dev Returns an `BooleanSlot` with member `value` located at `slot`.
     */
    function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
        assembly {
            r.slot := slot
        }
    }
    /**
     * @dev Returns an `Bytes32Slot` with member `value` located at `slot`.
     */
    function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
        assembly {
            r.slot := slot
        }
    }
    /**
     * @dev Returns an `Uint256Slot` with member `value` located at `slot`.
     */
    function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
        assembly {
            r.slot := slot
        }
    }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/UUPSUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "./lib/ReentrancyGuarded.sol";
import "./lib/EIP712.sol";
import "./lib/MerkleVerifier.sol";
import "./interfaces/IBlurExchange.sol";
import "./interfaces/IExecutionDelegate.sol";
import "./interfaces/IPolicyManager.sol";
import "./interfaces/IMatchingPolicy.sol";
import {
  Side,
  SignatureVersion,
  AssetType,
  Fee,
  Order,
  Input
} from "./lib/OrderStructs.sol";
/**
 * @title BlurExchange
 * @dev Core Blur exchange contract
 */
contract BlurExchange is IBlurExchange, ReentrancyGuarded, EIP712, OwnableUpgradeable, UUPSUpgradeable {
    /* Auth */
    uint256 public isOpen;
    modifier whenOpen() {
        require(isOpen == 1, "Closed");
        _;
    }
    event Opened();
    event Closed();
    function open() external onlyOwner {
        isOpen = 1;
        emit Opened();
    }
    function close() external onlyOwner {
        isOpen = 0;
        emit Closed();
    }
    // required by the OZ UUPS module
    function _authorizeUpgrade(address) internal override onlyOwner {}
    /* Constants */
    string public constant NAME = "Blur Exchange";
    string public constant VERSION = "1.0";
    uint256 public constant INVERSE_BASIS_POINT = 10_000;
    address public constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
    /* Variables */
    IExecutionDelegate public executionDelegate;
    IPolicyManager public policyManager;
    address public oracle;
    uint256 public blockRange;
    /* Storage */
    mapping(bytes32 => bool) public cancelledOrFilled;
    mapping(address => uint256) public nonces;
    /* Events */
    event OrdersMatched(
        address indexed maker,
        address indexed taker,
        Order sell,
        bytes32 sellHash,
        Order buy,
        bytes32 buyHash
    );
    event OrderCancelled(bytes32 hash);
    event NonceIncremented(address indexed trader, uint256 newNonce);
    event NewExecutionDelegate(IExecutionDelegate indexed executionDelegate);
    event NewPolicyManager(IPolicyManager indexed policyManager);
    event NewOracle(address indexed oracle);
    event NewBlockRange(uint256 blockRange);
    constructor() {
      _disableInitializers();
    }
    /* Constructor (for ERC1967) */
    function initialize(
        IExecutionDelegate _executionDelegate,
        IPolicyManager _policyManager,
        address _oracle,
        uint _blockRange
    ) external initializer {
        __Ownable_init();
        isOpen = 1;
        DOMAIN_SEPARATOR = _hashDomain(EIP712Domain({
            name              : NAME,
            version           : VERSION,
            chainId           : block.chainid,
            verifyingContract : address(this)
        }));
        executionDelegate = _executionDelegate;
        policyManager = _policyManager;
        oracle = _oracle;
        blockRange = _blockRange;
    }
    /* External Functions */
    /**
     * @dev Match two orders, ensuring validity of the match, and execute all associated state transitions. Protected against reentrancy by a contract-global lock.
     * @param sell Sell input
     * @param buy Buy input
     */
    function execute(Input calldata sell, Input calldata buy)
        external
        payable
        reentrancyGuard
        whenOpen
    {
        require(sell.order.side == Side.Sell);
        bytes32 sellHash = _hashOrder(sell.order, nonces[sell.order.trader]);
        bytes32 buyHash = _hashOrder(buy.order, nonces[buy.order.trader]);
        require(_validateOrderParameters(sell.order, sellHash), "Sell has invalid parameters");
        require(_validateOrderParameters(buy.order, buyHash), "Buy has invalid parameters");
        require(_validateSignatures(sell, sellHash), "Sell failed authorization");
        require(_validateSignatures(buy, buyHash), "Buy failed authorization");
        (uint256 price, uint256 tokenId, uint256 amount, AssetType assetType) = _canMatchOrders(sell.order, buy.order);
        /* Mark orders as filled. */
        cancelledOrFilled[sellHash] = true;
        cancelledOrFilled[buyHash] = true;
        _executeFundsTransfer(
            sell.order.trader,
            buy.order.trader,
            sell.order.paymentToken,
            sell.order.fees,
            price
        );
        _executeTokenTransfer(
            sell.order.collection,
            sell.order.trader,
            buy.order.trader,
            tokenId,
            amount,
            assetType
        );
        emit OrdersMatched(
            sell.order.listingTime <= buy.order.listingTime ? sell.order.trader : buy.order.trader,
            sell.order.listingTime > buy.order.listingTime ? sell.order.trader : buy.order.trader,
            sell.order,
            sellHash,
            buy.order,
            buyHash
        );
    }
    /**
     * @dev Cancel an order, preventing it from being matched. Must be called by the trader of the order
     * @param order Order to cancel
     */
    function cancelOrder(Order calldata order) public {
        /* Assert sender is authorized to cancel order. */
        require(msg.sender == order.trader);
        bytes32 hash = _hashOrder(order, nonces[order.trader]);
        require(cancelledOrFilled[hash] == false, "Order already cancelled or filled");
        if (!cancelledOrFilled[hash]) {
            /* Mark order as cancelled, preventing it from being matched. */
            cancelledOrFilled[hash] = true;
            emit OrderCancelled(hash);
        }
    }
    /**
     * @dev Cancel multiple orders
     * @param orders Orders to cancel
     */
    function cancelOrders(Order[] calldata orders) external {
        for (uint8 i = 0; i < orders.length; i++) {
            cancelOrder(orders[i]);
        }
    }
    /**
     * @dev Cancel all current orders for a user, preventing them from being matched. Must be called by the trader of the order
     */
    function incrementNonce() external {
        nonces[msg.sender] += 1;
        emit NonceIncremented(msg.sender, nonces[msg.sender]);
    }
    /* Setters */
    function setExecutionDelegate(IExecutionDelegate _executionDelegate)
        external
        onlyOwner
    {
        require(address(_executionDelegate) != address(0), "Address cannot be zero");
        executionDelegate = _executionDelegate;
        emit NewExecutionDelegate(executionDelegate);
    }
    function setPolicyManager(IPolicyManager _policyManager)
        external
        onlyOwner
    {
        require(address(_policyManager) != address(0), "Address cannot be zero");
        policyManager = _policyManager;
        emit NewPolicyManager(policyManager);
    }
    function setOracle(address _oracle)
        external
        onlyOwner
    {
        require(_oracle != address(0), "Address cannot be zero");
        oracle = _oracle;
        emit NewOracle(oracle);
    }
    function setBlockRange(uint256 _blockRange)
        external
        onlyOwner
    {
        blockRange = _blockRange;
        emit NewBlockRange(blockRange);
    }
    /* Internal Functions */
    /**
     * @dev Verify the validity of the order parameters
     * @param order order
     * @param orderHash hash of order
     */
    function _validateOrderParameters(Order calldata order, bytes32 orderHash)
        internal
        view
        returns (bool)
    {
        return (
            /* Order must have a trader. */
            (order.trader != address(0)) &&
            /* Order must not be cancelled or filled. */
            (cancelledOrFilled[orderHash] == false) &&
            /* Order must be settleable. */
            _canSettleOrder(order.listingTime, order.expirationTime)
        );
    }
    /**
     * @dev Check if the order can be settled at the current timestamp
     * @param listingTime order listing time
     * @param expirationTime order expiration time
     */
    function _canSettleOrder(uint256 listingTime, uint256 expirationTime)
        view
        internal
        returns (bool)
    {
        return (listingTime < block.timestamp) && (expirationTime == 0 || block.timestamp < expirationTime);
    }
    /**
     * @dev Verify the validity of the signatures
     * @param order order
     * @param orderHash hash of order
     */
    function _validateSignatures(Input calldata order, bytes32 orderHash)
        internal
        view
        returns (bool)
    {
        if (order.order.trader == msg.sender) {
          return true;
        }
        /* Check user authorization. */
        if (
            !_validateUserAuthorization(
                orderHash,
                order.order.trader,
                order.v,
                order.r,
                order.s,
                order.signatureVersion,
                order.extraSignature
            )
        ) {
            return false;
        }
        if (order.order.expirationTime == 0) {
            /* Check oracle authorization. */
            require(block.number - order.blockNumber < blockRange, "Signed block number out of range");
            if (
                !_validateOracleAuthorization(
                    orderHash,
                    order.signatureVersion,
                    order.extraSignature,
                    order.blockNumber
                )
            ) {
                return false;
            }
        }
        return true;
    }
    /**
     * @dev Verify the validity of the user signature
     * @param orderHash hash of the order
     * @param trader order trader who should be the signer
     * @param v v
     * @param r r
     * @param s s
     * @param signatureVersion signature version
     * @param extraSignature packed merkle path
     */
    function _validateUserAuthorization(
        bytes32 orderHash,
        address trader,
        uint8 v,
        bytes32 r,
        bytes32 s,
        SignatureVersion signatureVersion,
        bytes calldata extraSignature
    ) internal view returns (bool) {
        bytes32 hashToSign;
        if (signatureVersion == SignatureVersion.Single) {
            /* Single-listing authentication: Order signed by trader */
            hashToSign = _hashToSign(orderHash);
        } else if (signatureVersion == SignatureVersion.Bulk) {
            /* Bulk-listing authentication: Merkle root of orders signed by trader */
            (bytes32[] memory merklePath) = abi.decode(extraSignature, (bytes32[]));
            bytes32 computedRoot = MerkleVerifier._computeRoot(orderHash, merklePath);
            hashToSign = _hashToSignRoot(computedRoot);
        }
        return _verify(trader, hashToSign, v, r, s);
    }
    /**
     * @dev Verify the validity of oracle signature
     * @param orderHash hash of the order
     * @param signatureVersion signature version
     * @param extraSignature packed oracle signature
     * @param blockNumber block number used in oracle signature
     */
    function _validateOracleAuthorization(
        bytes32 orderHash,
        SignatureVersion signatureVersion,
        bytes calldata extraSignature,
        uint256 blockNumber
    ) internal view returns (bool) {
        bytes32 oracleHash = _hashToSignOracle(orderHash, blockNumber);
        uint8 v; bytes32 r; bytes32 s;
        if (signatureVersion == SignatureVersion.Single) {
            (v, r, s) = abi.decode(extraSignature, (uint8, bytes32, bytes32));
        } else if (signatureVersion == SignatureVersion.Bulk) {
            /* If the signature was a bulk listing the merkle path must be unpacked before the oracle signature. */
            (bytes32[] memory merklePath, uint8 _v, bytes32 _r, bytes32 _s) = abi.decode(extraSignature, (bytes32[], uint8, bytes32, bytes32));
            v = _v; r = _r; s = _s;
        }
        return _verify(oracle, oracleHash, v, r, s);
    }
    /**
     * @dev Verify ECDSA signature
     * @param signer Expected signer
     * @param digest Signature preimage
     * @param v v
     * @param r r
     * @param s s
     */
    function _verify(
        address signer,
        bytes32 digest,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (bool) {
        require(v == 27 || v == 28, "Invalid v parameter");
        address recoveredSigner = ecrecover(digest, v, r, s);
        if (recoveredSigner == address(0)) {
          return false;
        } else {
          return signer == recoveredSigner;
        }
    }
    /**
     * @dev Call the matching policy to check orders can be matched and get execution parameters
     * @param sell sell order
     * @param buy buy order
     */
    function _canMatchOrders(Order calldata sell, Order calldata buy)
        internal
        view
        returns (uint256 price, uint256 tokenId, uint256 amount, AssetType assetType)
    {
        bool canMatch;
        if (sell.listingTime <= buy.listingTime) {
            /* Seller is maker. */
            require(policyManager.isPolicyWhitelisted(sell.matchingPolicy), "Policy is not whitelisted");
            (canMatch, price, tokenId, amount, assetType) = IMatchingPolicy(sell.matchingPolicy).canMatchMakerAsk(sell, buy);
        } else {
            /* Buyer is maker. */
            require(policyManager.isPolicyWhitelisted(buy.matchingPolicy), "Policy is not whitelisted");
            (canMatch, price, tokenId, amount, assetType) = IMatchingPolicy(buy.matchingPolicy).canMatchMakerBid(buy, sell);
        }
        require(canMatch, "Orders cannot be matched");
        return (price, tokenId, amount, assetType);
    }
    /**
     * @dev Execute all ERC20 token / ETH transfers associated with an order match (fees and buyer => seller transfer)
     * @param seller seller
     * @param buyer buyer
     * @param paymentToken payment token
     * @param fees fees
     * @param price price
     */
    function _executeFundsTransfer(
        address seller,
        address buyer,
        address paymentToken,
        Fee[] calldata fees,
        uint256 price
    ) internal {
        if (paymentToken == address(0) && msg.sender == buyer) {
            require(msg.value == price, "Message value doesn't equal matching price");
        } else {
            require(msg.value == 0, "ETH should not be sent");
        }
        /* Take fee. */
        uint256 receiveAmount = _transferFees(fees, paymentToken, buyer, price);
        /* Transfer remainder to seller. */
        _transferTo(paymentToken, buyer, seller, receiveAmount);
    }
    /**
     * @dev Charge a fee in ETH or WETH
     * @param fees fees to distribute
     * @param paymentToken address of token to pay in
     * @param from address to charge fees
     * @param price price of token
     */
    function _transferFees(
        Fee[] calldata fees,
        address paymentToken,
        address from,
        uint256 price
    ) internal returns (uint256) {
        uint256 totalFee = 0;
        for (uint8 i = 0; i < fees.length; i++) {
            uint256 fee = (price * fees[i].rate) / INVERSE_BASIS_POINT;
            _transferTo(paymentToken, from, fees[i].recipient, fee);
            totalFee += fee;
        }
        require(totalFee <= price, "Total amount of fees are more than the price");
        /* Amount that will be received by seller. */
        uint256 receiveAmount = price - totalFee;
        return (receiveAmount);
    }
    /**
     * @dev Transfer amount in ETH or WETH
     * @param paymentToken address of token to pay in
     * @param from token sender
     * @param to token recipient
     * @param amount amount to transfer
     */
    function _transferTo(
        address paymentToken,
        address from,
        address to,
        uint256 amount
    ) internal {
        if (amount == 0) {
            return;
        }
        if (paymentToken == address(0)) {
            /* Transfer funds in ETH. */
            require(to != address(0), "Transfer to zero address");
            (bool success,) = payable(to).call{value: amount}("");
            require(success, "ETH transfer failed");
        } else if (paymentToken == WETH) {
            /* Transfer funds in WETH. */
            executionDelegate.transferERC20(WETH, from, to, amount);
        } else {
            revert("Invalid payment token");
        }
    }
    /**
     * @dev Execute call through delegate proxy
     * @param collection collection contract address
     * @param from seller address
     * @param to buyer address
     * @param tokenId tokenId
     * @param assetType asset type of the token
     */
    function _executeTokenTransfer(
        address collection,
        address from,
        address to,
        uint256 tokenId,
        uint256 amount,
        AssetType assetType
    ) internal {
        /* Assert collection exists. */
        require(_exists(collection), "Collection does not exist");
        /* Call execution delegate. */
        if (assetType == AssetType.ERC721) {
            executionDelegate.transferERC721(collection, from, to, tokenId);
        } else if (assetType == AssetType.ERC1155) {
            executionDelegate.transferERC1155(collection, from, to, tokenId, amount);
        }
    }
    /**
     * @dev Determine if the given address exists
     * @param what address to check
     */
    function _exists(address what)
        internal
        view
        returns (bool)
    {
        uint size;
        assembly {
            size := extcodesize(what)
        }
        return size > 0;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (proxy/utils/Initializable.sol)
pragma solidity ^0.8.2;
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 proxied contracts do not make use of 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.
 *
 * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
 * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
 * case an upgrade adds a module that needs to be initialized.
 *
 * For example:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * contract MyToken is ERC20Upgradeable {
 *     function initialize() initializer public {
 *         __ERC20_init("MyToken", "MTK");
 *     }
 * }
 * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
 *     function initializeV2() reinitializer(2) public {
 *         __ERC20Permit_init("MyToken");
 *     }
 * }
 * ```
 *
 * 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 {ERC1967Proxy-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.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
 * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() {
 *     _disableInitializers();
 * }
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     * @custom:oz-retyped-from bool
     */
    uint8 private _initialized;
    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;
    /**
     * @dev Triggered when the contract has been initialized or reinitialized.
     */
    event Initialized(uint8 version);
    /**
     * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
     * `onlyInitializing` functions can be used to initialize parent contracts. Equivalent to `reinitializer(1)`.
     */
    modifier initializer() {
        bool isTopLevelCall = !_initializing;
        require(
            (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
            "Initializable: contract is already initialized"
        );
        _initialized = 1;
        if (isTopLevelCall) {
            _initializing = true;
        }
        _;
        if (isTopLevelCall) {
            _initializing = false;
            emit Initialized(1);
        }
    }
    /**
     * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
     * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
     * used to initialize parent contracts.
     *
     * `initializer` is equivalent to `reinitializer(1)`, so a reinitializer may be used after the original
     * initialization step. This is essential to configure modules that are added through upgrades and that require
     * initialization.
     *
     * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
     * a contract, executing them in the right order is up to the developer or operator.
     */
    modifier reinitializer(uint8 version) {
        require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
        _initialized = version;
        _initializing = true;
        _;
        _initializing = false;
        emit Initialized(version);
    }
    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} and {reinitializer} modifiers, directly or indirectly.
     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }
    /**
     * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
     * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
     * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
     * through proxies.
     */
    function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized < type(uint8).max) {
            _initialized = type(uint8).max;
            emit Initialized(type(uint8).max);
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (proxy/utils/UUPSUpgradeable.sol)
pragma solidity ^0.8.0;
import "../../interfaces/draft-IERC1822Upgradeable.sol";
import "../ERC1967/ERC1967UpgradeUpgradeable.sol";
import "./Initializable.sol";
/**
 * @dev An upgradeability mechanism designed for UUPS proxies. The functions included here can perform an upgrade of an
 * {ERC1967Proxy}, when this contract is set as the implementation behind such a proxy.
 *
 * A security mechanism ensures that an upgrade does not turn off upgradeability accidentally, although this risk is
 * reinstated if the upgrade retains upgradeability but removes the security mechanism, e.g. by replacing
 * `UUPSUpgradeable` with a custom implementation of upgrades.
 *
 * The {_authorizeUpgrade} function must be overridden to include access restriction to the upgrade mechanism.
 *
 * _Available since v4.1._
 */
abstract contract UUPSUpgradeable is Initializable, IERC1822ProxiableUpgradeable, ERC1967UpgradeUpgradeable {
    function __UUPSUpgradeable_init() internal onlyInitializing {
    }
    function __UUPSUpgradeable_init_unchained() internal onlyInitializing {
    }
    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
    address private immutable __self = address(this);
    /**
     * @dev Check that the execution is being performed through a delegatecall call and that the execution context is
     * a proxy contract with an implementation (as defined in ERC1967) pointing to self. This should only be the case
     * for UUPS and transparent proxies that are using the current contract as their implementation. Execution of a
     * function through ERC1167 minimal proxies (clones) would not normally pass this test, but is not guaranteed to
     * fail.
     */
    modifier onlyProxy() {
        require(address(this) != __self, "Function must be called through delegatecall");
        require(_getImplementation() == __self, "Function must be called through active proxy");
        _;
    }
    /**
     * @dev Check that the execution is not being performed through a delegate call. This allows a function to be
     * callable on the implementing contract but not through proxies.
     */
    modifier notDelegated() {
        require(address(this) == __self, "UUPSUpgradeable: must not be called through delegatecall");
        _;
    }
    /**
     * @dev Implementation of the ERC1822 {proxiableUUID} function. This returns the storage slot used by the
     * implementation. It is used to validate that the this implementation remains valid after an upgrade.
     *
     * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks
     * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this
     * function revert if invoked through a proxy. This is guaranteed by the `notDelegated` modifier.
     */
    function proxiableUUID() external view virtual override notDelegated returns (bytes32) {
        return _IMPLEMENTATION_SLOT;
    }
    /**
     * @dev Upgrade the implementation of the proxy to `newImplementation`.
     *
     * Calls {_authorizeUpgrade}.
     *
     * Emits an {Upgraded} event.
     */
    function upgradeTo(address newImplementation) external virtual onlyProxy {
        _authorizeUpgrade(newImplementation);
        _upgradeToAndCallUUPS(newImplementation, new bytes(0), false);
    }
    /**
     * @dev Upgrade the implementation of the proxy to `newImplementation`, and subsequently execute the function call
     * encoded in `data`.
     *
     * Calls {_authorizeUpgrade}.
     *
     * Emits an {Upgraded} event.
     */
    function upgradeToAndCall(address newImplementation, bytes memory data) external payable virtual onlyProxy {
        _authorizeUpgrade(newImplementation);
        _upgradeToAndCallUUPS(newImplementation, data, true);
    }
    /**
     * @dev Function that should revert when `msg.sender` is not authorized to upgrade the contract. Called by
     * {upgradeTo} and {upgradeToAndCall}.
     *
     * Normally, this function will use an xref:access.adoc[access control] modifier such as {Ownable-onlyOwner}.
     *
     * ```solidity
     * function _authorizeUpgrade(address) internal override onlyOwner {}
     * ```
     */
    function _authorizeUpgrade(address newImplementation) internal virtual;
    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../utils/ContextUpgradeable.sol";
import "../proxy/utils/Initializable.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
    address private _owner;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    function __Ownable_init() internal onlyInitializing {
        __Ownable_init_unchained();
    }
    function __Ownable_init_unchained() internal onlyInitializing {
        _transferOwnership(_msgSender());
    }
    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }
    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }
    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        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 {
        _transferOwnership(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");
        _transferOwnership(newOwner);
    }
    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[49] private __gap;
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
/**
 * @title ReentrancyGuarded
 * @dev Protections for reentrancy attacks
 */
contract ReentrancyGuarded {
    bool private reentrancyLock = false;
    /* Prevent a contract function from being reentrant-called. */
    modifier reentrancyGuard {
        require(!reentrancyLock, "Reentrancy detected");
        reentrancyLock = true;
        _;
        reentrancyLock = false;
    }
    uint256[49] private __gap;
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
import {Order, Fee} from "./OrderStructs.sol";
/**
 * @title EIP712
 * @dev Contains all of the order hashing functions for EIP712 compliant signatures
 */
contract EIP712 {
    struct EIP712Domain {
        string  name;
        string  version;
        uint256 chainId;
        address verifyingContract;
    }
    /* Order typehash for EIP 712 compatibility. */
    bytes32 constant public FEE_TYPEHASH = keccak256(
        "Fee(uint16 rate,address recipient)"
    );
    bytes32 constant public ORDER_TYPEHASH = keccak256(
        "Order(address trader,uint8 side,address matchingPolicy,address collection,uint256 tokenId,uint256 amount,address paymentToken,uint256 price,uint256 listingTime,uint256 expirationTime,Fee[] fees,uint256 salt,bytes extraParams,uint256 nonce)Fee(uint16 rate,address recipient)"
    );
    bytes32 constant public ORACLE_ORDER_TYPEHASH = keccak256(
        "OracleOrder(Order order,uint256 blockNumber)Fee(uint16 rate,address recipient)Order(address trader,uint8 side,address matchingPolicy,address collection,uint256 tokenId,uint256 amount,address paymentToken,uint256 price,uint256 listingTime,uint256 expirationTime,Fee[] fees,uint256 salt,bytes extraParams,uint256 nonce)"
    );
    bytes32 constant public ROOT_TYPEHASH = keccak256(
        "Root(bytes32 root)"
    );
    bytes32 constant EIP712DOMAIN_TYPEHASH = keccak256(
        "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
    );
    bytes32 DOMAIN_SEPARATOR;
    function _hashDomain(EIP712Domain memory eip712Domain)
        internal
        pure
        returns (bytes32)
    {
        return keccak256(
            abi.encode(
                EIP712DOMAIN_TYPEHASH,
                keccak256(bytes(eip712Domain.name)),
                keccak256(bytes(eip712Domain.version)),
                eip712Domain.chainId,
                eip712Domain.verifyingContract
            )
        );
    }
    function _hashFee(Fee calldata fee)
        internal 
        pure
        returns (bytes32)
    {
        return keccak256(
            abi.encode(
                FEE_TYPEHASH,
                fee.rate,
                fee.recipient
            )
        );
    }
    function _packFees(Fee[] calldata fees)
        internal
        pure
        returns (bytes32)
    {
        bytes32[] memory feeHashes = new bytes32[](
            fees.length
        );
        for (uint256 i = 0; i < fees.length; i++) {
            feeHashes[i] = _hashFee(fees[i]);
        }
        return keccak256(abi.encodePacked(feeHashes));
    }
    function _hashOrder(Order calldata order, uint256 nonce)
        internal
        pure
        returns (bytes32)
    {
        return keccak256(
            bytes.concat(
                abi.encode(
                      ORDER_TYPEHASH,
                      order.trader,
                      order.side,
                      order.matchingPolicy,
                      order.collection,
                      order.tokenId,
                      order.amount,
                      order.paymentToken,
                      order.price,
                      order.listingTime,
                      order.expirationTime,
                      _packFees(order.fees),
                      order.salt,
                      keccak256(order.extraParams)
                ),
                abi.encode(nonce)
            )
        );
    }
    function _hashToSign(bytes32 orderHash)
        internal
        view
        returns (bytes32 hash)
    {
        return keccak256(abi.encodePacked(
            "\\x19\\x01",
            DOMAIN_SEPARATOR,
            orderHash
        ));
    }
    function _hashToSignRoot(bytes32 root)
        internal
        view
        returns (bytes32 hash)
    {
        return keccak256(abi.encodePacked(
            "\\x19\\x01",
            DOMAIN_SEPARATOR,
            keccak256(abi.encode(
                ROOT_TYPEHASH,
                root
            ))
        ));
    }
    function _hashToSignOracle(bytes32 orderHash, uint256 blockNumber)
        internal
        view
        returns (bytes32 hash)
    {
        return keccak256(abi.encodePacked(
            "\\x19\\x01",
            DOMAIN_SEPARATOR,
            keccak256(abi.encode(
                ORACLE_ORDER_TYPEHASH,
                orderHash,
                blockNumber
            ))
        ));
    }
    uint256[44] private __gap;
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
/**
 * @title MerkleVerifier
 * @dev Utility functions for Merkle tree computations
 */
library MerkleVerifier {
    error InvalidProof();
    /**
     * @dev Verify the merkle proof
     * @param leaf leaf
     * @param root root
     * @param proof proof
     */
    function _verifyProof(
        bytes32 leaf,
        bytes32 root,
        bytes32[] memory proof
    ) public pure {
        bytes32 computedRoot = _computeRoot(leaf, proof);
        if (computedRoot != root) {
            revert InvalidProof();
        }
    }
    /**
     * @dev Compute the merkle root
     * @param leaf leaf
     * @param proof proof
     */
    function _computeRoot(
        bytes32 leaf,
        bytes32[] memory proof
    ) public pure returns (bytes32) {
        bytes32 computedHash = leaf;
        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];
            computedHash = _hashPair(computedHash, proofElement);
        }
        return computedHash;
    }
    function _hashPair(bytes32 a, bytes32 b) private pure returns (bytes32) {
        return a < b ? _efficientHash(a, b) : _efficientHash(b, a);
    }
    function _efficientHash(
        bytes32 a,
        bytes32 b
    ) private pure returns (bytes32 value) {
        assembly {
            mstore(0x00, a)
            mstore(0x20, b)
            value := keccak256(0x00, 0x40)
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
import {Input, Order} from "../lib/OrderStructs.sol";
import "./IExecutionDelegate.sol";
import "./IPolicyManager.sol";
interface IBlurExchange {
    function nonces(address) external view returns (uint256);
    function close() external;
    function initialize(
        IExecutionDelegate _executionDelegate,
        IPolicyManager _policyManager,
        address _oracle,
        uint _blockRange
    ) external;
    function setExecutionDelegate(IExecutionDelegate _executionDelegate) external;
    function setPolicyManager(IPolicyManager _policyManager) external;
    function setOracle(address _oracle) external;
    function setBlockRange(uint256 _blockRange) external;
    function cancelOrder(Order calldata order) external;
    function cancelOrders(Order[] calldata orders) external;
    function incrementNonce() external;
    function execute(Input calldata sell, Input calldata buy)
        external
        payable;
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
interface IExecutionDelegate {
    function approveContract(address _contract) external;
    function denyContract(address _contract) external;
    function revokeApproval() external;
    function grantApproval() external;
    function transferERC721Unsafe(address collection, address from, address to, uint256 tokenId) external;
    function transferERC721(address collection, address from, address to, uint256 tokenId) external;
    function transferERC1155(address collection, address from, address to, uint256 tokenId, uint256 amount) external;
    function transferERC20(address token, address from, address to, uint256 amount) external;
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
interface IPolicyManager {
    function addPolicy(address policy) external;
    function removePolicy(address policy) external;
    function isPolicyWhitelisted(address policy) external view returns (bool);
    function viewWhitelistedPolicies(uint256 cursor, uint256 size) external view returns (address[] memory, uint256);
    function viewCountWhitelistedPolicies() external view returns (uint256);
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
import {Order, AssetType} from "../lib/OrderStructs.sol";
interface IMatchingPolicy {
    function canMatchMakerAsk(Order calldata makerAsk, Order calldata takerBid)
        external
        view
        returns (
            bool,
            uint256,
            uint256,
            uint256,
            AssetType
        );
    function canMatchMakerBid(Order calldata makerBid, Order calldata takerAsk)
        external
        view
        returns (
            bool,
            uint256,
            uint256,
            uint256,
            AssetType
        );
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
enum Side { Buy, Sell }
enum SignatureVersion { Single, Bulk }
enum AssetType { ERC721, ERC1155 }
struct Fee {
    uint16 rate;
    address payable recipient;
}
struct Order {
    address trader;
    Side side;
    address matchingPolicy;
    address collection;
    uint256 tokenId;
    uint256 amount;
    address paymentToken;
    uint256 price;
    uint256 listingTime;
    /* Order expiration timestamp - 0 for oracle cancellations. */
    uint256 expirationTime;
    Fee[] fees;
    uint256 salt;
    bytes extraParams;
}
struct Input {
    Order order;
    uint8 v;
    bytes32 r;
    bytes32 s;
    bytes extraSignature;
    SignatureVersion signatureVersion;
    uint256 blockNumber;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)
pragma solidity ^0.8.1;
/**
 * @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
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.
        return account.code.length > 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");
        (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");
        (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");
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal 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
                /// @solidity memory-safe-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (interfaces/draft-IERC1822.sol)
pragma solidity ^0.8.0;
/**
 * @dev ERC1822: Universal Upgradeable Proxy Standard (UUPS) documents a method for upgradeability through a simplified
 * proxy whose upgrades are fully controlled by the current implementation.
 */
interface IERC1822ProxiableUpgradeable {
    /**
     * @dev Returns the storage slot that the proxiable contract assumes is being used to store the implementation
     * address.
     *
     * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks
     * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this
     * function revert if invoked through a proxy.
     */
    function proxiableUUID() external view returns (bytes32);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (proxy/ERC1967/ERC1967Upgrade.sol)
pragma solidity ^0.8.2;
import "../beacon/IBeaconUpgradeable.sol";
import "../../interfaces/draft-IERC1822Upgradeable.sol";
import "../../utils/AddressUpgradeable.sol";
import "../../utils/StorageSlotUpgradeable.sol";
import "../utils/Initializable.sol";
/**
 * @dev This abstract contract provides getters and event emitting update functions for
 * https://eips.ethereum.org/EIPS/eip-1967[EIP1967] slots.
 *
 * _Available since v4.1._
 *
 * @custom:oz-upgrades-unsafe-allow delegatecall
 */
abstract contract ERC1967UpgradeUpgradeable is Initializable {
    function __ERC1967Upgrade_init() internal onlyInitializing {
    }
    function __ERC1967Upgrade_init_unchained() internal onlyInitializing {
    }
    // This is the keccak-256 hash of "eip1967.proxy.rollback" subtracted by 1
    bytes32 private constant _ROLLBACK_SLOT = 0x4910fdfa16fed3260ed0e7147f7cc6da11a60208b5b9406d12a635614ffd9143;
    /**
     * @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 Emitted when the implementation is upgraded.
     */
    event Upgraded(address indexed implementation);
    /**
     * @dev Returns the current implementation address.
     */
    function _getImplementation() internal view returns (address) {
        return StorageSlotUpgradeable.getAddressSlot(_IMPLEMENTATION_SLOT).value;
    }
    /**
     * @dev Stores a new address in the EIP1967 implementation slot.
     */
    function _setImplementation(address newImplementation) private {
        require(AddressUpgradeable.isContract(newImplementation), "ERC1967: new implementation is not a contract");
        StorageSlotUpgradeable.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
    }
    /**
     * @dev Perform implementation upgrade
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeTo(address newImplementation) internal {
        _setImplementation(newImplementation);
        emit Upgraded(newImplementation);
    }
    /**
     * @dev Perform implementation upgrade with additional setup call.
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeToAndCall(
        address newImplementation,
        bytes memory data,
        bool forceCall
    ) internal {
        _upgradeTo(newImplementation);
        if (data.length > 0 || forceCall) {
            _functionDelegateCall(newImplementation, data);
        }
    }
    /**
     * @dev Perform implementation upgrade with security checks for UUPS proxies, and additional setup call.
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeToAndCallUUPS(
        address newImplementation,
        bytes memory data,
        bool forceCall
    ) internal {
        // Upgrades from old implementations will perform a rollback test. This test requires the new
        // implementation to upgrade back to the old, non-ERC1822 compliant, implementation. Removing
        // this special case will break upgrade paths from old UUPS implementation to new ones.
        if (StorageSlotUpgradeable.getBooleanSlot(_ROLLBACK_SLOT).value) {
            _setImplementation(newImplementation);
        } else {
            try IERC1822ProxiableUpgradeable(newImplementation).proxiableUUID() returns (bytes32 slot) {
                require(slot == _IMPLEMENTATION_SLOT, "ERC1967Upgrade: unsupported proxiableUUID");
            } catch {
                revert("ERC1967Upgrade: new implementation is not UUPS");
            }
            _upgradeToAndCall(newImplementation, data, forceCall);
        }
    }
    /**
     * @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 Emitted when the admin account has changed.
     */
    event AdminChanged(address previousAdmin, address newAdmin);
    /**
     * @dev Returns the current admin.
     */
    function _getAdmin() internal view returns (address) {
        return StorageSlotUpgradeable.getAddressSlot(_ADMIN_SLOT).value;
    }
    /**
     * @dev Stores a new address in the EIP1967 admin slot.
     */
    function _setAdmin(address newAdmin) private {
        require(newAdmin != address(0), "ERC1967: new admin is the zero address");
        StorageSlotUpgradeable.getAddressSlot(_ADMIN_SLOT).value = newAdmin;
    }
    /**
     * @dev Changes the admin of the proxy.
     *
     * Emits an {AdminChanged} event.
     */
    function _changeAdmin(address newAdmin) internal {
        emit AdminChanged(_getAdmin(), newAdmin);
        _setAdmin(newAdmin);
    }
    /**
     * @dev The storage slot of the UpgradeableBeacon contract which defines the implementation for this proxy.
     * This is bytes32(uint256(keccak256('eip1967.proxy.beacon')) - 1)) and is validated in the constructor.
     */
    bytes32 internal constant _BEACON_SLOT = 0xa3f0ad74e5423aebfd80d3ef4346578335a9a72aeaee59ff6cb3582b35133d50;
    /**
     * @dev Emitted when the beacon is upgraded.
     */
    event BeaconUpgraded(address indexed beacon);
    /**
     * @dev Returns the current beacon.
     */
    function _getBeacon() internal view returns (address) {
        return StorageSlotUpgradeable.getAddressSlot(_BEACON_SLOT).value;
    }
    /**
     * @dev Stores a new beacon in the EIP1967 beacon slot.
     */
    function _setBeacon(address newBeacon) private {
        require(AddressUpgradeable.isContract(newBeacon), "ERC1967: new beacon is not a contract");
        require(
            AddressUpgradeable.isContract(IBeaconUpgradeable(newBeacon).implementation()),
            "ERC1967: beacon implementation is not a contract"
        );
        StorageSlotUpgradeable.getAddressSlot(_BEACON_SLOT).value = newBeacon;
    }
    /**
     * @dev Perform beacon upgrade with additional setup call. Note: This upgrades the address of the beacon, it does
     * not upgrade the implementation contained in the beacon (see {UpgradeableBeacon-_setImplementation} for that).
     *
     * Emits a {BeaconUpgraded} event.
     */
    function _upgradeBeaconToAndCall(
        address newBeacon,
        bytes memory data,
        bool forceCall
    ) internal {
        _setBeacon(newBeacon);
        emit BeaconUpgraded(newBeacon);
        if (data.length > 0 || forceCall) {
            _functionDelegateCall(IBeaconUpgradeable(newBeacon).implementation(), data);
        }
    }
    /**
     * @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) private returns (bytes memory) {
        require(AddressUpgradeable.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 AddressUpgradeable.verifyCallResult(success, returndata, "Address: low-level delegate call failed");
    }
    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (proxy/beacon/IBeacon.sol)
pragma solidity ^0.8.0;
/**
 * @dev This is the interface that {BeaconProxy} expects of its beacon.
 */
interface IBeaconUpgradeable {
    /**
     * @dev Must return an address that can be used as a delegate call target.
     *
     * {BeaconProxy} will check that this address is a contract.
     */
    function implementation() external view returns (address);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (utils/StorageSlot.sol)
pragma solidity ^0.8.0;
/**
 * @dev Library for reading and writing primitive types to specific storage slots.
 *
 * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
 * This library helps with reading and writing to such slots without the need for inline assembly.
 *
 * The functions in this library return Slot structs that contain a `value` member that can be used to read or write.
 *
 * Example usage to set ERC1967 implementation slot:
 * ```
 * contract ERC1967 {
 *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
 *
 *     function _getImplementation() internal view returns (address) {
 *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
 *     }
 *
 *     function _setImplementation(address newImplementation) internal {
 *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
 *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
 *     }
 * }
 * ```
 *
 * _Available since v4.1 for `address`, `bool`, `bytes32`, and `uint256`._
 */
library StorageSlotUpgradeable {
    struct AddressSlot {
        address value;
    }
    struct BooleanSlot {
        bool value;
    }
    struct Bytes32Slot {
        bytes32 value;
    }
    struct Uint256Slot {
        uint256 value;
    }
    /**
     * @dev Returns an `AddressSlot` with member `value` located at `slot`.
     */
    function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }
    /**
     * @dev Returns an `BooleanSlot` with member `value` located at `slot`.
     */
    function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }
    /**
     * @dev Returns an `Bytes32Slot` with member `value` located at `slot`.
     */
    function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }
    /**
     * @dev Returns an `Uint256Slot` with member `value` located at `slot`.
     */
    function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^0.8.0;
import "../proxy/utils/Initializable.sol";
/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract ContextUpgradeable is Initializable {
    function __Context_init() internal onlyInitializing {
    }
    function __Context_init_unchained() internal onlyInitializing {
    }
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
import {EnumerableSet} from "@openzeppelin/contracts/utils/structs/EnumerableSet.sol";
import {IPolicyManager} from "./interfaces/IPolicyManager.sol";
/**
 * @title PolicyManager
 * @dev Manages the policy whitelist for the Blur exchange
 */
contract PolicyManager is IPolicyManager, Ownable {
    using EnumerableSet for EnumerableSet.AddressSet;
    EnumerableSet.AddressSet private _whitelistedPolicies;
    event PolicyRemoved(address indexed policy);
    event PolicyWhitelisted(address indexed policy);
    /**
     * @notice Add matching policy
     * @param policy address of policy to add
     */
    function addPolicy(address policy) external override onlyOwner {
        require(!_whitelistedPolicies.contains(policy), "Already whitelisted");
        _whitelistedPolicies.add(policy);
        emit PolicyWhitelisted(policy);
    }
    /**
     * @notice Remove matching policy
     * @param policy address of policy to remove
     */
    function removePolicy(address policy) external override onlyOwner {
        require(_whitelistedPolicies.contains(policy), "Not whitelisted");
        _whitelistedPolicies.remove(policy);
        emit PolicyRemoved(policy);
    }
    /**
     * @notice Returns if a policy has been added
     * @param policy address of the policy to check
     */
    function isPolicyWhitelisted(address policy) external view override returns (bool) {
        return _whitelistedPolicies.contains(policy);
    }
    /**
     * @notice View number of whitelisted policies
     */
    function viewCountWhitelistedPolicies() external view override returns (uint256) {
        return _whitelistedPolicies.length();
    }
    /**
     * @notice See whitelisted policies
     * @param cursor cursor
     * @param size size
     */
    function viewWhitelistedPolicies(uint256 cursor, uint256 size)
        external
        view
        override
        returns (address[] memory, uint256)
    {
        uint256 length = size;
        if (length > _whitelistedPolicies.length() - cursor) {
            length = _whitelistedPolicies.length() - cursor;
        }
        address[] memory whitelistedPolicies = new address[](length);
        for (uint256 i = 0; i < length; i++) {
            whitelistedPolicies[i] = _whitelistedPolicies.at(cursor + i);
        }
        return (whitelistedPolicies, cursor + length);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_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 {
        _transferOwnership(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");
        _transferOwnership(newOwner);
    }
    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/structs/EnumerableSet.sol)
pragma solidity ^0.8.0;
/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.
    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping(bytes32 => uint256) _indexes;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];
        if (valueIndex != 0) {
            // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.
            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;
            if (lastIndex != toDeleteIndex) {
                bytes32 lastvalue = set._values[lastIndex];
                // Move the last value to the index where the value to delete is
                set._values[toDeleteIndex] = lastvalue;
                // Update the index for the moved value
                set._indexes[lastvalue] = valueIndex; // Replace lastvalue's index to valueIndex
            }
            // Delete the slot where the moved value was stored
            set._values.pop();
            // Delete the index for the deleted slot
            delete set._indexes[value];
            return true;
        } else {
            return false;
        }
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }
    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }
    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        return set._values[index];
    }
    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function _values(Set storage set) private view returns (bytes32[] memory) {
        return set._values;
    }
    // Bytes32Set
    struct Bytes32Set {
        Set _inner;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }
    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }
    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }
    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(Bytes32Set storage set) internal view returns (bytes32[] memory) {
        return _values(set._inner);
    }
    // AddressSet
    struct AddressSet {
        Set _inner;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }
    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }
    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }
    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(AddressSet storage set) internal view returns (address[] memory) {
        bytes32[] memory store = _values(set._inner);
        address[] memory result;
        assembly {
            result := store
        }
        return result;
    }
    // UintSet
    struct UintSet {
        Set _inner;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }
    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }
    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(UintSet storage set) internal view returns (uint256[] memory) {
        bytes32[] memory store = _values(set._inner);
        uint256[] memory result;
        assembly {
            result := store
        }
        return result;
    }
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
interface IPolicyManager {
    function addPolicy(address policy) external;
    function removePolicy(address policy) external;
    function isPolicyWhitelisted(address policy) external view returns (bool);
    function viewWhitelistedPolicies(uint256 cursor, uint256 size) external view returns (address[] memory, uint256);
    function viewCountWhitelistedPolicies() external view returns (uint256);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^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 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) {
        return msg.sender;
    }
    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
import {Order, AssetType} from "../lib/OrderStructs.sol";
import {IMatchingPolicy} from "../interfaces/IMatchingPolicy.sol";
/**
 * @title StandardPolicyERC721
 * @dev Policy for matching orders at a fixed price for a specific ERC721 tokenId
 */
contract StandardPolicyERC721 is IMatchingPolicy {
    function canMatchMakerAsk(Order calldata makerAsk, Order calldata takerBid)
        external
        pure
        override
        returns (
            bool,
            uint256,
            uint256,
            uint256,
            AssetType
        )
    {
        return (
            (makerAsk.side != takerBid.side) &&
            (makerAsk.paymentToken == takerBid.paymentToken) &&
            (makerAsk.collection == takerBid.collection) &&
            (makerAsk.tokenId == takerBid.tokenId) &&
            (makerAsk.amount == 1) &&
            (takerBid.amount == 1) &&
            (makerAsk.matchingPolicy == takerBid.matchingPolicy) &&
            (makerAsk.price == takerBid.price),
            makerAsk.price,
            makerAsk.tokenId,
            1,
            AssetType.ERC721
        );
    }
    function canMatchMakerBid(Order calldata makerBid, Order calldata takerAsk)
        external
        pure
        override
        returns (
            bool,
            uint256,
            uint256,
            uint256,
            AssetType
        )
    {
        return (
            (makerBid.side != takerAsk.side) &&
            (makerBid.paymentToken == takerAsk.paymentToken) &&
            (makerBid.collection == takerAsk.collection) &&
            (makerBid.tokenId == takerAsk.tokenId) &&
            (makerBid.amount == 1) &&
            (takerAsk.amount == 1) &&
            (makerBid.matchingPolicy == takerAsk.matchingPolicy) &&
            (makerBid.price == takerAsk.price),
            makerBid.price,
            makerBid.tokenId,
            1,
            AssetType.ERC721
        );
    }
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
enum Side { Buy, Sell }
enum SignatureVersion { Single, Bulk }
enum AssetType { ERC721, ERC1155 }
struct Fee {
    uint16 rate;
    address payable recipient;
}
struct Order {
    address trader;
    Side side;
    address matchingPolicy;
    address collection;
    uint256 tokenId;
    uint256 amount;
    address paymentToken;
    uint256 price;
    uint256 listingTime;
    /* Order expiration timestamp - 0 for oracle cancellations. */
    uint256 expirationTime;
    Fee[] fees;
    uint256 salt;
    bytes extraParams;
}
struct Input {
    Order order;
    uint8 v;
    bytes32 r;
    bytes32 s;
    bytes extraSignature;
    SignatureVersion signatureVersion;
    uint256 blockNumber;
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
import {Order, AssetType} from "../lib/OrderStructs.sol";
interface IMatchingPolicy {
    function canMatchMakerAsk(Order calldata makerAsk, Order calldata takerBid)
        external
        view
        returns (
            bool,
            uint256,
            uint256,
            uint256,
            AssetType
        );
    function canMatchMakerBid(Order calldata makerBid, Order calldata takerAsk)
        external
        view
        returns (
            bool,
            uint256,
            uint256,
            uint256,
            AssetType
        );
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC1155/IERC1155.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import {IExecutionDelegate} from "./interfaces/IExecutionDelegate.sol";
/**
 * @title ExecutionDelegate
 * @dev Proxy contract to manage user token approvals
 */
contract ExecutionDelegate is IExecutionDelegate, Ownable {
    using Address for address;
    mapping(address => bool) public contracts;
    mapping(address => bool) public revokedApproval;
    modifier approvedContract() {
        require(contracts[msg.sender], "Contract is not approved to make transfers");
        _;
    }
    event ApproveContract(address indexed _contract);
    event DenyContract(address indexed _contract);
    event RevokeApproval(address indexed user);
    event GrantApproval(address indexed user);
    /**
     * @dev Approve contract to call transfer functions
     * @param _contract address of contract to approve
     */
    function approveContract(address _contract) onlyOwner external {
        contracts[_contract] = true;
        emit ApproveContract(_contract);
    }
    /**
     * @dev Revoke approval of contract to call transfer functions
     * @param _contract address of contract to revoke approval
     */
    function denyContract(address _contract) onlyOwner external {
        contracts[_contract] = false;
        emit DenyContract(_contract);
    }
    /**
     * @dev Block contract from making transfers on-behalf of a specific user
     */
    function revokeApproval() external {
        revokedApproval[msg.sender] = true;
        emit RevokeApproval(msg.sender);
    }
    /**
     * @dev Allow contract to make transfers on-behalf of a specific user
     */
    function grantApproval() external {
        revokedApproval[msg.sender] = false;
        emit GrantApproval(msg.sender);
    }
    /**
     * @dev Transfer ERC721 token using `transferFrom`
     * @param collection address of the collection
     * @param from address of the sender
     * @param to address of the recipient
     * @param tokenId tokenId
     */
    function transferERC721Unsafe(address collection, address from, address to, uint256 tokenId)
        approvedContract
        external
    {
        require(revokedApproval[from] == false, "User has revoked approval");
        IERC721(collection).transferFrom(from, to, tokenId);
    }
    /**
     * @dev Transfer ERC721 token using `safeTransferFrom`
     * @param collection address of the collection
     * @param from address of the sender
     * @param to address of the recipient
     * @param tokenId tokenId
     */
    function transferERC721(address collection, address from, address to, uint256 tokenId)
        approvedContract
        external
    {
        require(revokedApproval[from] == false, "User has revoked approval");
        IERC721(collection).safeTransferFrom(from, to, tokenId);
    }
    /**
     * @dev Transfer ERC1155 token using `safeTransferFrom`
     * @param collection address of the collection
     * @param from address of the sender
     * @param to address of the recipient
     * @param tokenId tokenId
     * @param amount amount
     */
    function transferERC1155(address collection, address from, address to, uint256 tokenId, uint256 amount)
        approvedContract
        external
    {
        require(revokedApproval[from] == false, "User has revoked approval");
        IERC1155(collection).safeTransferFrom(from, to, tokenId, amount, "");
    }
    /**
     * @dev Transfer ERC20 token
     * @param token address of the token
     * @param from address of the sender
     * @param to address of the recipient
     * @param amount amount
     */
    function transferERC20(address token, address from, address to, uint256 amount)
        approvedContract
        external
    {
        require(revokedApproval[from] == false, "User has revoked approval");
        bytes memory data = abi.encodeWithSelector(IERC20.transferFrom.selector, from, to, amount);
        bytes memory returndata = token.functionCall(data);
        if (returndata.length > 0) {
          require(abi.decode(returndata, (bool)), "ERC20 transfer failed");
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);
    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);
    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);
    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);
    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);
    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);
    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)
pragma solidity ^0.8.0;
import "../../utils/introspection/IERC165.sol";
/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);
    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);
    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;
    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;
    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;
    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);
    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;
    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC1155/IERC1155.sol)
pragma solidity ^0.8.0;
import "../../utils/introspection/IERC165.sol";
/**
 * @dev Required interface of an ERC1155 compliant contract, as defined in the
 * https://eips.ethereum.org/EIPS/eip-1155[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155 is IERC165 {
    /**
     * @dev Emitted when `value` tokens of token type `id` are transferred from `from` to `to` by `operator`.
     */
    event TransferSingle(address indexed operator, address indexed from, address indexed to, uint256 id, uint256 value);
    /**
     * @dev Equivalent to multiple {TransferSingle} events, where `operator`, `from` and `to` are the same for all
     * transfers.
     */
    event TransferBatch(
        address indexed operator,
        address indexed from,
        address indexed to,
        uint256[] ids,
        uint256[] values
    );
    /**
     * @dev Emitted when `account` grants or revokes permission to `operator` to transfer their tokens, according to
     * `approved`.
     */
    event ApprovalForAll(address indexed account, address indexed operator, bool approved);
    /**
     * @dev Emitted when the URI for token type `id` changes to `value`, if it is a non-programmatic URI.
     *
     * If an {URI} event was emitted for `id`, the standard
     * https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[guarantees] that `value` will equal the value
     * returned by {IERC1155MetadataURI-uri}.
     */
    event URI(string value, uint256 indexed id);
    /**
     * @dev Returns the amount of tokens of token type `id` owned by `account`.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function balanceOf(address account, uint256 id) external view returns (uint256);
    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {balanceOf}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(address[] calldata accounts, uint256[] calldata ids)
        external
        view
        returns (uint256[] memory);
    /**
     * @dev Grants or revokes permission to `operator` to transfer the caller's tokens, according to `approved`,
     *
     * Emits an {ApprovalForAll} event.
     *
     * Requirements:
     *
     * - `operator` cannot be the caller.
     */
    function setApprovalForAll(address operator, bool approved) external;
    /**
     * @dev Returns true if `operator` is approved to transfer ``account``'s tokens.
     *
     * See {setApprovalForAll}.
     */
    function isApprovedForAll(address account, address operator) external view returns (bool);
    /**
     * @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If the caller is not `from`, it must be have been approved to spend ``from``'s tokens via {setApprovalForAll}.
     * - `from` must have a balance of tokens of type `id` of at least `amount`.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes calldata data
    ) external;
    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {safeTransferFrom}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] calldata ids,
        uint256[] calldata amounts,
        bytes calldata data
    ) external;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_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 {
        _transferOwnership(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");
        _transferOwnership(newOwner);
    }
    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)
pragma solidity ^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;
        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");
        (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");
        (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");
        (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");
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal 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
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
interface IExecutionDelegate {
    function approveContract(address _contract) external;
    function denyContract(address _contract) external;
    function revokeApproval() external;
    function grantApproval() external;
    function transferERC721Unsafe(address collection, address from, address to, uint256 tokenId) external;
    function transferERC721(address collection, address from, address to, uint256 tokenId) external;
    function transferERC1155(address collection, address from, address to, uint256 tokenId, uint256 amount) external;
    function transferERC20(address token, address from, address to, uint256 amount) external;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^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 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) {
        return msg.sender;
    }
    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.8.10 <0.9.0;
import "@divergencetech/ethier/contracts/crypto/SignatureChecker.sol";
import "@divergencetech/ethier/contracts/crypto/SignerManager.sol";
import "@divergencetech/ethier/contracts/erc721/BaseTokenURI.sol";
import "@divergencetech/ethier/contracts/erc721/ERC721ACommon.sol";
import "@divergencetech/ethier/contracts/erc721/ERC721Redeemer.sol";
import "@divergencetech/ethier/contracts/sales/FixedPriceSeller.sol";
import "@divergencetech/ethier/contracts/utils/Monotonic.sol";
import "@openzeppelin/contracts/token/common/ERC2981.sol";
import "@openzeppelin/contracts/access/AccessControlEnumerable.sol";
import "@openzeppelin/contracts/utils/structs/EnumerableSet.sol";
interface ITokenURIGenerator {
    function tokenURI(uint256 tokenId) external view returns (string memory);
}
// @author divergence.xyz
contract Moonbirds is
    ERC721ACommon,
    BaseTokenURI,
    FixedPriceSeller,
    SignerManager,
    ERC2981,
    AccessControlEnumerable
{
    using EnumerableSet for EnumerableSet.AddressSet;
    using ERC721Redeemer for ERC721Redeemer.Claims;
    using Monotonic for Monotonic.Increaser;
    using SignatureChecker for EnumerableSet.AddressSet;
    IERC721 public immutable proof;
    /**
    @notice Role of administrative users allowed to expel a Moonbird from the
    nest.
    @dev See expelFromNest().
     */
    bytes32 public constant EXPULSION_ROLE = keccak256("EXPULSION_ROLE");
    constructor(
        string memory name,
        string memory symbol,
        IERC721 _proof,
        address payable beneficiary,
        address payable royaltyReceiver
    )
        ERC721ACommon(name, symbol)
        BaseTokenURI("")
        FixedPriceSeller(
            2.5 ether,
            // Not including a separate pool for PROOF holders, taking the total
            // to 10k. We don't enforce buyer limits here because it's already
            // done by only issuing a single signature per address, and double
            // enforcement would waste gas.
            Seller.SellerConfig({
                totalInventory: 8_000,
                lockTotalInventory: true,
                maxPerAddress: 0,
                maxPerTx: 0,
                freeQuota: 125,
                lockFreeQuota: false,
                reserveFreeQuota: true
            }),
            beneficiary
        )
    {
        proof = _proof;
        _setDefaultRoyalty(royaltyReceiver, 500);
        _grantRole(DEFAULT_ADMIN_ROLE, msg.sender);
    }
    /**
    @dev Mint tokens purchased via the Seller.
     */
    function _handlePurchase(
        address to,
        uint256 n,
        bool
    ) internal override {
        _safeMint(to, n);
        // We're using two separate pools (one from Seller, and one for PROOF
        // minting), so add an extra layer of checks for this invariant. This
        // should never fail as each pool has its own restriction, and is in
        // place purely for tests (hence assert).
        assert(totalSupply() <= 10_000);
    }
    /**
    @dev Record of already-used signatures.
     */
    mapping(bytes32 => bool) public usedMessages;
    /**
    @notice Mint as a non-holder of PROOF tokens.
     */
    function mintPublic(
        address to,
        bytes32 nonce,
        bytes calldata sig
    ) external payable {
        signers.requireValidSignature(
            signaturePayload(to, nonce),
            sig,
            usedMessages
        );
        _purchase(to, 1);
    }
    /**
    @notice Returns whether the address has minted with the particular nonce. If
    true, future calls to mint() with the same parameters will fail.
    @dev In production we will never issue more than a single nonce per address,
    but this allows for testing with a single address.
     */
    function alreadyMinted(address to, bytes32 nonce)
        external
        view
        returns (bool)
    {
        return
            usedMessages[
                SignatureChecker.generateMessage(signaturePayload(to, nonce))
            ];
    }
    /**
    @dev Constructs the buffer that is hashed for validation with a minting
    signature.
     */
    function signaturePayload(address to, bytes32 nonce)
        internal
        pure
        returns (bytes memory)
    {
        return abi.encodePacked(to, nonce);
    }
    /**
    @notice Two guaranteed mints per PROOF holder.
    @dev This is specifically tracked because unclaimed tokens will be minted to
    the PROOF wallet, so the pool guarantees an upper bound.
     */
    uint256 public proofPoolRemaining = 2000;
    ERC721Redeemer.Claims private redeemedPROOF;
    /**
    @dev Used by both PROOF-holder and PROOF-admin minting from the pool.
     */
    modifier reducePROOFPool(uint256 n) {
        require(n <= proofPoolRemaining, "Moonbirds: PROOF pool exhausted");
        proofPoolRemaining -= n;
        _;
    }
    /**
    @notice Flag indicating whether holders of PROOF passes can mint.
     */
    bool public proofMintingOpen = false;
    /**
    @notice Sets whether holders of PROOF passes can mint.
     */
    function setPROOFMintingOpen(bool open) external onlyOwner {
        proofMintingOpen = open;
    }
    /**
    @notice Mint as a holder of a PROOF token.
    @dev Repeat a PROOF token ID twice to redeem both of its claims; recurring
    values SHOULD be adjacent for improved gas (eg [1,1,2,2] not [1,2,1,2]).
     */
    function mintPROOF(uint256[] calldata proofTokenIds)
        external
        reducePROOFPool(proofTokenIds.length)
    {
        require(proofMintingOpen, "Moonbirds: PROOF minting closed");
        uint256 n = redeemedPROOF.redeem(2, msg.sender, proof, proofTokenIds);
        _handlePurchase(msg.sender, n, true);
    }
    /**
    @notice Returns how many additional Moonbirds can be claimed with the PROOF
    token.
     */
    function proofClaimsRemaining(uint256 tokenId)
        external
        view
        returns (uint256)
    {
        require(tokenId < 1000, "Token doesn't exist");
        return 2 - redeemedPROOF.claimed(tokenId);
    }
    /**
    @notice Mint unclaimed tokens from the PROOF-holder pool.
     */
    function mintUnclaimed(address to, uint256 n)
        external
        onlyOwner
        reducePROOFPool(n)
    {
        _handlePurchase(to, n, true);
    }
    /**
    @dev tokenId to nesting start time (0 = not nesting).
     */
    mapping(uint256 => uint256) private nestingStarted;
    /**
    @dev Cumulative per-token nesting, excluding the current period.
     */
    mapping(uint256 => uint256) private nestingTotal;
    /**
    @notice Returns the length of time, in seconds, that the Moonbird has
    nested.
    @dev Nesting is tied to a specific Moonbird, not to the owner, so it doesn't
    reset upon sale.
    @return nesting Whether the Moonbird is currently nesting. MAY be true with
    zero current nesting if in the same block as nesting began.
    @return current Zero if not currently nesting, otherwise the length of time
    since the most recent nesting began.
    @return total Total period of time for which the Moonbird has nested across
    its life, including the current period.
     */
    function nestingPeriod(uint256 tokenId)
        external
        view
        returns (
            bool nesting,
            uint256 current,
            uint256 total
        )
    {
        uint256 start = nestingStarted[tokenId];
        if (start != 0) {
            nesting = true;
            current = block.timestamp - start;
        }
        total = current + nestingTotal[tokenId];
    }
    /**
    @dev MUST only be modified by safeTransferWhileNesting(); if set to 2 then
    the _beforeTokenTransfer() block while nesting is disabled.
     */
    uint256 private nestingTransfer = 1;
    /**
    @notice Transfer a token between addresses while the Moonbird is minting,
    thus not resetting the nesting period.
     */
    function safeTransferWhileNesting(
        address from,
        address to,
        uint256 tokenId
    ) external {
        require(ownerOf(tokenId) == _msgSender(), "Moonbirds: Only owner");
        nestingTransfer = 2;
        safeTransferFrom(from, to, tokenId);
        nestingTransfer = 1;
    }
    /**
    @dev Block transfers while nesting.
     */
    function _beforeTokenTransfers(
        address,
        address,
        uint256 startTokenId,
        uint256 quantity
    ) internal view override {
        uint256 tokenId = startTokenId;
        for (uint256 end = tokenId + quantity; tokenId < end; ++tokenId) {
            require(
                nestingStarted[tokenId] == 0 || nestingTransfer == 2,
                "Moonbirds: nesting"
            );
        }
    }
    /**
    @dev Emitted when a Moonbird begins nesting.
     */
    event Nested(uint256 indexed tokenId);
    /**
    @dev Emitted when a Moonbird stops nesting; either through standard means or
    by expulsion.
     */
    event Unnested(uint256 indexed tokenId);
    /**
    @dev Emitted when a Moonbird is expelled from the nest.
     */
    event Expelled(uint256 indexed tokenId);
    /**
    @notice Whether nesting is currently allowed.
    @dev If false then nesting is blocked, but unnesting is always allowed.
     */
    bool public nestingOpen = false;
    /**
    @notice Toggles the `nestingOpen` flag.
     */
    function setNestingOpen(bool open) external onlyOwner {
        nestingOpen = open;
    }
    /**
    @notice Changes the Moonbird's nesting status.
    */
    function toggleNesting(uint256 tokenId)
        internal
        onlyApprovedOrOwner(tokenId)
    {
        uint256 start = nestingStarted[tokenId];
        if (start == 0) {
            require(nestingOpen, "Moonbirds: nesting closed");
            nestingStarted[tokenId] = block.timestamp;
            emit Nested(tokenId);
        } else {
            nestingTotal[tokenId] += block.timestamp - start;
            nestingStarted[tokenId] = 0;
            emit Unnested(tokenId);
        }
    }
    /**
    @notice Changes the Moonbirds' nesting statuss (what's the plural of status?
    statii? statuses? status? The plural of sheep is sheep; maybe it's also the
    plural of status).
    @dev Changes the Moonbirds' nesting sheep (see @notice).
     */
    function toggleNesting(uint256[] calldata tokenIds) external {
        uint256 n = tokenIds.length;
        for (uint256 i = 0; i < n; ++i) {
            toggleNesting(tokenIds[i]);
        }
    }
    /**
    @notice Admin-only ability to expel a Moonbird from the nest.
    @dev As most sales listings use off-chain signatures it's impossible to
    detect someone who has nested and then deliberately undercuts the floor
    price in the knowledge that the sale can't proceed. This function allows for
    monitoring of such practices and expulsion if abuse is detected, allowing
    the undercutting bird to be sold on the open market. Since OpenSea uses
    isApprovedForAll() in its pre-listing checks, we can't block by that means
    because nesting would then be all-or-nothing for all of a particular owner's
    Moonbirds.
     */
    function expelFromNest(uint256 tokenId) external onlyRole(EXPULSION_ROLE) {
        require(nestingStarted[tokenId] != 0, "Moonbirds: not nested");
        nestingTotal[tokenId] += block.timestamp - nestingStarted[tokenId];
        nestingStarted[tokenId] = 0;
        emit Unnested(tokenId);
        emit Expelled(tokenId);
    }
    /**
    @dev Required override to select the correct baseTokenURI.
     */
    function _baseURI()
        internal
        view
        override(BaseTokenURI, ERC721A)
        returns (string memory)
    {
        return BaseTokenURI._baseURI();
    }
    /**
    @notice If set, contract to which tokenURI() calls are proxied.
     */
    ITokenURIGenerator public renderingContract;
    /**
    @notice Sets the optional tokenURI override contract.
     */
    function setRenderingContract(ITokenURIGenerator _contract)
        external
        onlyOwner
    {
        renderingContract = _contract;
    }
    /**
    @notice If renderingContract is set then returns its tokenURI(tokenId)
    return value, otherwise returns the standard baseTokenURI + tokenId.
     */
    function tokenURI(uint256 tokenId)
        public
        view
        override
        returns (string memory)
    {
        if (address(renderingContract) != address(0)) {
            return renderingContract.tokenURI(tokenId);
        }
        return super.tokenURI(tokenId);
    }
    /**
    @notice Sets the contract-wide royalty info.
     */
    function setRoyaltyInfo(address receiver, uint96 feeBasisPoints)
        external
        onlyOwner
    {
        _setDefaultRoyalty(receiver, feeBasisPoints);
    }
    function supportsInterface(bytes4 interfaceId)
        public
        view
        override(ERC721ACommon, ERC2981, AccessControlEnumerable)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }
}
// SPDX-License-Identifier: MIT
// Creator: Chiru Labs
pragma solidity ^0.8.4;
import '@openzeppelin/contracts/token/ERC721/IERC721.sol';
import '@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol';
import '@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol';
import '@openzeppelin/contracts/utils/Address.sol';
import '@openzeppelin/contracts/utils/Context.sol';
import '@openzeppelin/contracts/utils/Strings.sol';
import '@openzeppelin/contracts/utils/introspection/ERC165.sol';
error ApprovalCallerNotOwnerNorApproved();
error ApprovalQueryForNonexistentToken();
error ApproveToCaller();
error ApprovalToCurrentOwner();
error BalanceQueryForZeroAddress();
error MintToZeroAddress();
error MintZeroQuantity();
error OwnerQueryForNonexistentToken();
error TransferCallerNotOwnerNorApproved();
error TransferFromIncorrectOwner();
error TransferToNonERC721ReceiverImplementer();
error TransferToZeroAddress();
error URIQueryForNonexistentToken();
/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension. Built to optimize for lower gas during batch mints.
 *
 * Assumes serials are sequentially minted starting at _startTokenId() (defaults to 0, e.g. 0, 1, 2, 3..).
 *
 * Assumes that an owner cannot have more than 2**64 - 1 (max value of uint64) of supply.
 *
 * Assumes that the maximum token id cannot exceed 2**256 - 1 (max value of uint256).
 */
contract ERC721A is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;
    // Compiler will pack this into a single 256bit word.
    struct TokenOwnership {
        // The address of the owner.
        address addr;
        // Keeps track of the start time of ownership with minimal overhead for tokenomics.
        uint64 startTimestamp;
        // Whether the token has been burned.
        bool burned;
    }
    // Compiler will pack this into a single 256bit word.
    struct AddressData {
        // Realistically, 2**64-1 is more than enough.
        uint64 balance;
        // Keeps track of mint count with minimal overhead for tokenomics.
        uint64 numberMinted;
        // Keeps track of burn count with minimal overhead for tokenomics.
        uint64 numberBurned;
        // For miscellaneous variable(s) pertaining to the address
        // (e.g. number of whitelist mint slots used).
        // If there are multiple variables, please pack them into a uint64.
        uint64 aux;
    }
    // The tokenId of the next token to be minted.
    uint256 internal _currentIndex;
    // The number of tokens burned.
    uint256 internal _burnCounter;
    // Token name
    string private _name;
    // Token symbol
    string private _symbol;
    // Mapping from token ID to ownership details
    // An empty struct value does not necessarily mean the token is unowned. See _ownershipOf implementation for details.
    mapping(uint256 => TokenOwnership) internal _ownerships;
    // Mapping owner address to address data
    mapping(address => AddressData) private _addressData;
    // Mapping from token ID to approved address
    mapping(uint256 => address) private _tokenApprovals;
    // Mapping from owner to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
        _currentIndex = _startTokenId();
    }
    /**
     * To change the starting tokenId, please override this function.
     */
    function _startTokenId() internal view virtual returns (uint256) {
        return 0;
    }
    /**
     * @dev Burned tokens are calculated here, use _totalMinted() if you want to count just minted tokens.
     */
    function totalSupply() public view returns (uint256) {
        // Counter underflow is impossible as _burnCounter cannot be incremented
        // more than _currentIndex - _startTokenId() times
        unchecked {
            return _currentIndex - _burnCounter - _startTokenId();
        }
    }
    /**
     * Returns the total amount of tokens minted in the contract.
     */
    function _totalMinted() internal view returns (uint256) {
        // Counter underflow is impossible as _currentIndex does not decrement,
        // and it is initialized to _startTokenId()
        unchecked {
            return _currentIndex - _startTokenId();
        }
    }
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            super.supportsInterface(interfaceId);
    }
    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view override returns (uint256) {
        if (owner == address(0)) revert BalanceQueryForZeroAddress();
        return uint256(_addressData[owner].balance);
    }
    /**
     * Returns the number of tokens minted by `owner`.
     */
    function _numberMinted(address owner) internal view returns (uint256) {
        return uint256(_addressData[owner].numberMinted);
    }
    /**
     * Returns the number of tokens burned by or on behalf of `owner`.
     */
    function _numberBurned(address owner) internal view returns (uint256) {
        return uint256(_addressData[owner].numberBurned);
    }
    /**
     * Returns the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
     */
    function _getAux(address owner) internal view returns (uint64) {
        return _addressData[owner].aux;
    }
    /**
     * Sets the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
     * If there are multiple variables, please pack them into a uint64.
     */
    function _setAux(address owner, uint64 aux) internal {
        _addressData[owner].aux = aux;
    }
    /**
     * Gas spent here starts off proportional to the maximum mint batch size.
     * It gradually moves to O(1) as tokens get transferred around in the collection over time.
     */
    function _ownershipOf(uint256 tokenId) internal view returns (TokenOwnership memory) {
        uint256 curr = tokenId;
        unchecked {
            if (_startTokenId() <= curr && curr < _currentIndex) {
                TokenOwnership memory ownership = _ownerships[curr];
                if (!ownership.burned) {
                    if (ownership.addr != address(0)) {
                        return ownership;
                    }
                    // Invariant:
                    // There will always be an ownership that has an address and is not burned
                    // before an ownership that does not have an address and is not burned.
                    // Hence, curr will not underflow.
                    while (true) {
                        curr--;
                        ownership = _ownerships[curr];
                        if (ownership.addr != address(0)) {
                            return ownership;
                        }
                    }
                }
            }
        }
        revert OwnerQueryForNonexistentToken();
    }
    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view override returns (address) {
        return _ownershipOf(tokenId).addr;
    }
    /**
     * @dev See {IERC721Metadata-name}.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }
    /**
     * @dev See {IERC721Metadata-symbol}.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }
    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        if (!_exists(tokenId)) revert URIQueryForNonexistentToken();
        string memory baseURI = _baseURI();
        return bytes(baseURI).length != 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : '';
    }
    /**
     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
     * by default, can be overriden in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return '';
    }
    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public override {
        address owner = ERC721A.ownerOf(tokenId);
        if (to == owner) revert ApprovalToCurrentOwner();
        if (_msgSender() != owner && !isApprovedForAll(owner, _msgSender())) {
            revert ApprovalCallerNotOwnerNorApproved();
        }
        _approve(to, tokenId, owner);
    }
    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view override returns (address) {
        if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();
        return _tokenApprovals[tokenId];
    }
    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        if (operator == _msgSender()) revert ApproveToCaller();
        _operatorApprovals[_msgSender()][operator] = approved;
        emit ApprovalForAll(_msgSender(), operator, approved);
    }
    /**
     * @dev See {IERC721-isApprovedForAll}.
     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }
    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        _transfer(from, to, tokenId);
    }
    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        safeTransferFrom(from, to, tokenId, '');
    }
    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) public virtual override {
        _transfer(from, to, tokenId);
        if (to.isContract() && !_checkContractOnERC721Received(from, to, tokenId, _data)) {
            revert TransferToNonERC721ReceiverImplementer();
        }
    }
    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted (`_mint`),
     */
    function _exists(uint256 tokenId) internal view returns (bool) {
        return _startTokenId() <= tokenId && tokenId < _currentIndex &&
            !_ownerships[tokenId].burned;
    }
    function _safeMint(address to, uint256 quantity) internal {
        _safeMint(to, quantity, '');
    }
    /**
     * @dev Safely mints `quantity` tokens and transfers them to `to`.
     *
     * Requirements:
     *
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called for each safe transfer.
     * - `quantity` must be greater than 0.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(
        address to,
        uint256 quantity,
        bytes memory _data
    ) internal {
        _mint(to, quantity, _data, true);
    }
    /**
     * @dev Mints `quantity` tokens and transfers them to `to`.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `quantity` must be greater than 0.
     *
     * Emits a {Transfer} event.
     */
    function _mint(
        address to,
        uint256 quantity,
        bytes memory _data,
        bool safe
    ) internal {
        uint256 startTokenId = _currentIndex;
        if (to == address(0)) revert MintToZeroAddress();
        if (quantity == 0) revert MintZeroQuantity();
        _beforeTokenTransfers(address(0), to, startTokenId, quantity);
        // Overflows are incredibly unrealistic.
        // balance or numberMinted overflow if current value of either + quantity > 1.8e19 (2**64) - 1
        // updatedIndex overflows if _currentIndex + quantity > 1.2e77 (2**256) - 1
        unchecked {
            _addressData[to].balance += uint64(quantity);
            _addressData[to].numberMinted += uint64(quantity);
            _ownerships[startTokenId].addr = to;
            _ownerships[startTokenId].startTimestamp = uint64(block.timestamp);
            uint256 updatedIndex = startTokenId;
            uint256 end = updatedIndex + quantity;
            if (safe && to.isContract()) {
                do {
                    emit Transfer(address(0), to, updatedIndex);
                    if (!_checkContractOnERC721Received(address(0), to, updatedIndex++, _data)) {
                        revert TransferToNonERC721ReceiverImplementer();
                    }
                } while (updatedIndex != end);
                // Reentrancy protection
                if (_currentIndex != startTokenId) revert();
            } else {
                do {
                    emit Transfer(address(0), to, updatedIndex++);
                } while (updatedIndex != end);
            }
            _currentIndex = updatedIndex;
        }
        _afterTokenTransfers(address(0), to, startTokenId, quantity);
    }
    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) private {
        TokenOwnership memory prevOwnership = _ownershipOf(tokenId);
        if (prevOwnership.addr != from) revert TransferFromIncorrectOwner();
        bool isApprovedOrOwner = (_msgSender() == from ||
            isApprovedForAll(from, _msgSender()) ||
            getApproved(tokenId) == _msgSender());
        if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
        if (to == address(0)) revert TransferToZeroAddress();
        _beforeTokenTransfers(from, to, tokenId, 1);
        // Clear approvals from the previous owner
        _approve(address(0), tokenId, from);
        // Underflow of the sender's balance is impossible because we check for
        // ownership above and the recipient's balance can't realistically overflow.
        // Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
        unchecked {
            _addressData[from].balance -= 1;
            _addressData[to].balance += 1;
            TokenOwnership storage currSlot = _ownerships[tokenId];
            currSlot.addr = to;
            currSlot.startTimestamp = uint64(block.timestamp);
            // If the ownership slot of tokenId+1 is not explicitly set, that means the transfer initiator owns it.
            // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
            uint256 nextTokenId = tokenId + 1;
            TokenOwnership storage nextSlot = _ownerships[nextTokenId];
            if (nextSlot.addr == address(0)) {
                // This will suffice for checking _exists(nextTokenId),
                // as a burned slot cannot contain the zero address.
                if (nextTokenId != _currentIndex) {
                    nextSlot.addr = from;
                    nextSlot.startTimestamp = prevOwnership.startTimestamp;
                }
            }
        }
        emit Transfer(from, to, tokenId);
        _afterTokenTransfers(from, to, tokenId, 1);
    }
    /**
     * @dev This is equivalent to _burn(tokenId, false)
     */
    function _burn(uint256 tokenId) internal virtual {
        _burn(tokenId, false);
    }
    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId, bool approvalCheck) internal virtual {
        TokenOwnership memory prevOwnership = _ownershipOf(tokenId);
        address from = prevOwnership.addr;
        if (approvalCheck) {
            bool isApprovedOrOwner = (_msgSender() == from ||
                isApprovedForAll(from, _msgSender()) ||
                getApproved(tokenId) == _msgSender());
            if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
        }
        _beforeTokenTransfers(from, address(0), tokenId, 1);
        // Clear approvals from the previous owner
        _approve(address(0), tokenId, from);
        // Underflow of the sender's balance is impossible because we check for
        // ownership above and the recipient's balance can't realistically overflow.
        // Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
        unchecked {
            AddressData storage addressData = _addressData[from];
            addressData.balance -= 1;
            addressData.numberBurned += 1;
            // Keep track of who burned the token, and the timestamp of burning.
            TokenOwnership storage currSlot = _ownerships[tokenId];
            currSlot.addr = from;
            currSlot.startTimestamp = uint64(block.timestamp);
            currSlot.burned = true;
            // If the ownership slot of tokenId+1 is not explicitly set, that means the burn initiator owns it.
            // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
            uint256 nextTokenId = tokenId + 1;
            TokenOwnership storage nextSlot = _ownerships[nextTokenId];
            if (nextSlot.addr == address(0)) {
                // This will suffice for checking _exists(nextTokenId),
                // as a burned slot cannot contain the zero address.
                if (nextTokenId != _currentIndex) {
                    nextSlot.addr = from;
                    nextSlot.startTimestamp = prevOwnership.startTimestamp;
                }
            }
        }
        emit Transfer(from, address(0), tokenId);
        _afterTokenTransfers(from, address(0), tokenId, 1);
        // Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.
        unchecked {
            _burnCounter++;
        }
    }
    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits a {Approval} event.
     */
    function _approve(
        address to,
        uint256 tokenId,
        address owner
    ) private {
        _tokenApprovals[tokenId] = to;
        emit Approval(owner, to, tokenId);
    }
    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param _data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkContractOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) private returns (bool) {
        try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
            return retval == IERC721Receiver(to).onERC721Received.selector;
        } catch (bytes memory reason) {
            if (reason.length == 0) {
                revert TransferToNonERC721ReceiverImplementer();
            } else {
                assembly {
                    revert(add(32, reason), mload(reason))
                }
            }
        }
    }
    /**
     * @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
     * And also called before burning one token.
     *
     * startTokenId - the first token id to be transferred
     * quantity - the amount to be transferred
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, `from`'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, `tokenId` will be burned by `from`.
     * - `from` and `to` are never both zero.
     */
    function _beforeTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual {}
    /**
     * @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes
     * minting.
     * And also called after one token has been burned.
     *
     * startTokenId - the first token id to be transferred
     * quantity - the amount to be transferred
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, `from`'s `tokenId` has been
     * transferred to `to`.
     * - When `from` is zero, `tokenId` has been minted for `to`.
     * - When `to` is zero, `tokenId` has been burned by `from`.
     * - `from` and `to` are never both zero.
     */
    function _afterTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual {}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/structs/EnumerableSet.sol)
pragma solidity ^0.8.0;
/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.
    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping(bytes32 => uint256) _indexes;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];
        if (valueIndex != 0) {
            // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.
            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;
            if (lastIndex != toDeleteIndex) {
                bytes32 lastvalue = set._values[lastIndex];
                // Move the last value to the index where the value to delete is
                set._values[toDeleteIndex] = lastvalue;
                // Update the index for the moved value
                set._indexes[lastvalue] = valueIndex; // Replace lastvalue's index to valueIndex
            }
            // Delete the slot where the moved value was stored
            set._values.pop();
            // Delete the index for the deleted slot
            delete set._indexes[value];
            return true;
        } else {
            return false;
        }
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }
    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }
    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        return set._values[index];
    }
    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function _values(Set storage set) private view returns (bytes32[] memory) {
        return set._values;
    }
    // Bytes32Set
    struct Bytes32Set {
        Set _inner;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }
    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }
    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }
    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(Bytes32Set storage set) internal view returns (bytes32[] memory) {
        return _values(set._inner);
    }
    // AddressSet
    struct AddressSet {
        Set _inner;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }
    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }
    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }
    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(AddressSet storage set) internal view returns (address[] memory) {
        bytes32[] memory store = _values(set._inner);
        address[] memory result;
        assembly {
            result := store
        }
        return result;
    }
    // UintSet
    struct UintSet {
        Set _inner;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }
    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }
    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(UintSet storage set) internal view returns (uint256[] memory) {
        bytes32[] memory store = _values(set._inner);
        uint256[] memory result;
        assembly {
            result := store
        }
        return result;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/structs/BitMaps.sol)
pragma solidity ^0.8.0;
/**
 * @dev Library for managing uint256 to bool mapping in a compact and efficient way, providing the keys are sequential.
 * Largelly inspired by Uniswap's https://github.com/Uniswap/merkle-distributor/blob/master/contracts/MerkleDistributor.sol[merkle-distributor].
 */
library BitMaps {
    struct BitMap {
        mapping(uint256 => uint256) _data;
    }
    /**
     * @dev Returns whether the bit at `index` is set.
     */
    function get(BitMap storage bitmap, uint256 index) internal view returns (bool) {
        uint256 bucket = index >> 8;
        uint256 mask = 1 << (index & 0xff);
        return bitmap._data[bucket] & mask != 0;
    }
    /**
     * @dev Sets the bit at `index` to the boolean `value`.
     */
    function setTo(
        BitMap storage bitmap,
        uint256 index,
        bool value
    ) internal {
        if (value) {
            set(bitmap, index);
        } else {
            unset(bitmap, index);
        }
    }
    /**
     * @dev Sets the bit at `index`.
     */
    function set(BitMap storage bitmap, uint256 index) internal {
        uint256 bucket = index >> 8;
        uint256 mask = 1 << (index & 0xff);
        bitmap._data[bucket] |= mask;
    }
    /**
     * @dev Unsets the bit at `index`.
     */
    function unset(BitMap storage bitmap, uint256 index) internal {
        uint256 bucket = index >> 8;
        uint256 mask = 1 << (index & 0xff);
        bitmap._data[bucket] &= ~mask;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/math/Math.sol)
pragma solidity ^0.8.0;
/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }
    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }
    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }
    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a / b + (a % b == 0 ? 0 : 1);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)
pragma solidity ^0.8.0;
import "./IERC165.sol";
/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/cryptography/ECDSA.sol)
pragma solidity ^0.8.0;
import "../Strings.sol";
/**
 * @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 {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS,
        InvalidSignatureV
    }
    function _throwError(RecoverError error) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert("ECDSA: invalid signature");
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert("ECDSA: invalid signature length");
        } else if (error == RecoverError.InvalidSignatureS) {
            revert("ECDSA: invalid signature 's' value");
        } else if (error == RecoverError.InvalidSignatureV) {
            revert("ECDSA: invalid signature 'v' value");
        }
    }
    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature` or error string. 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.
     *
     * Documentation for signature generation:
     * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
     * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
        // Check the signature length
        // - case 65: r,s,v signature (standard)
        // - case 64: r,vs signature (cf https://eips.ethereum.org/EIPS/eip-2098) _Available since v4.1._
        if (signature.length == 65) {
            bytes32 r;
            bytes32 s;
            uint8 v;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            assembly {
                r := mload(add(signature, 0x20))
                s := mload(add(signature, 0x40))
                v := byte(0, mload(add(signature, 0x60)))
            }
            return tryRecover(hash, v, r, s);
        } else if (signature.length == 64) {
            bytes32 r;
            bytes32 vs;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            assembly {
                r := mload(add(signature, 0x20))
                vs := mload(add(signature, 0x40))
            }
            return tryRecover(hash, r, vs);
        } else {
            return (address(0), RecoverError.InvalidSignatureLength);
        }
    }
    /**
     * @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) {
        (address recovered, RecoverError error) = tryRecover(hash, signature);
        _throwError(error);
        return recovered;
    }
    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
     *
     * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        bytes32 r,
        bytes32 vs
    ) internal pure returns (address, RecoverError) {
        bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
        uint8 v = uint8((uint256(vs) >> 255) + 27);
        return tryRecover(hash, v, r, s);
    }
    /**
     * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
     *
     * _Available since v4.2._
     */
    function recover(
        bytes32 hash,
        bytes32 r,
        bytes32 vs
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, r, vs);
        _throwError(error);
        return recovered;
    }
    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
     * `r` and `s` signature fields separately.
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address, RecoverError) {
        // 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 (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): 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.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return (address(0), RecoverError.InvalidSignatureS);
        }
        if (v != 27 && v != 28) {
            return (address(0), RecoverError.InvalidSignatureV);
        }
        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        if (signer == address(0)) {
            return (address(0), RecoverError.InvalidSignature);
        }
        return (signer, RecoverError.NoError);
    }
    /**
     * @dev Overload of {ECDSA-recover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function recover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, v, r, s);
        _throwError(error);
        return recovered;
    }
    /**
     * @dev Returns an Ethereum Signed Message, created from a `hash`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * 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));
    }
    /**
     * @dev Returns an Ethereum Signed Message, created from `s`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\\x19Ethereum Signed Message:\
", Strings.toString(s.length), s));
    }
    /**
     * @dev Returns an Ethereum Signed Typed Data, created from a
     * `domainSeparator` and a `structHash`. This produces hash corresponding
     * to the one signed with the
     * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
     * JSON-RPC method as part of EIP-712.
     *
     * See {recover}.
     */
    function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\\x19\\x01", domainSeparator, structHash));
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)
pragma solidity ^0.8.0;
/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal 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);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }
    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }
    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^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 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) {
        return msg.sender;
    }
    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)
pragma solidity ^0.8.1;
/**
 * @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
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.
        return account.code.length > 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");
        (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");
        (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");
        (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");
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal 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
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/common/ERC2981.sol)
pragma solidity ^0.8.0;
import "../../interfaces/IERC2981.sol";
import "../../utils/introspection/ERC165.sol";
/**
 * @dev Implementation of the NFT Royalty Standard, a standardized way to retrieve royalty payment information.
 *
 * Royalty information can be specified globally for all token ids via {_setDefaultRoyalty}, and/or individually for
 * specific token ids via {_setTokenRoyalty}. The latter takes precedence over the first.
 *
 * Royalty is specified as a fraction of sale price. {_feeDenominator} is overridable but defaults to 10000, meaning the
 * fee is specified in basis points by default.
 *
 * IMPORTANT: ERC-2981 only specifies a way to signal royalty information and does not enforce its payment. See
 * https://eips.ethereum.org/EIPS/eip-2981#optional-royalty-payments[Rationale] in the EIP. Marketplaces are expected to
 * voluntarily pay royalties together with sales, but note that this standard is not yet widely supported.
 *
 * _Available since v4.5._
 */
abstract contract ERC2981 is IERC2981, ERC165 {
    struct RoyaltyInfo {
        address receiver;
        uint96 royaltyFraction;
    }
    RoyaltyInfo private _defaultRoyaltyInfo;
    mapping(uint256 => RoyaltyInfo) private _tokenRoyaltyInfo;
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC165) returns (bool) {
        return interfaceId == type(IERC2981).interfaceId || super.supportsInterface(interfaceId);
    }
    /**
     * @inheritdoc IERC2981
     */
    function royaltyInfo(uint256 _tokenId, uint256 _salePrice)
        external
        view
        virtual
        override
        returns (address, uint256)
    {
        RoyaltyInfo memory royalty = _tokenRoyaltyInfo[_tokenId];
        if (royalty.receiver == address(0)) {
            royalty = _defaultRoyaltyInfo;
        }
        uint256 royaltyAmount = (_salePrice * royalty.royaltyFraction) / _feeDenominator();
        return (royalty.receiver, royaltyAmount);
    }
    /**
     * @dev The denominator with which to interpret the fee set in {_setTokenRoyalty} and {_setDefaultRoyalty} as a
     * fraction of the sale price. Defaults to 10000 so fees are expressed in basis points, but may be customized by an
     * override.
     */
    function _feeDenominator() internal pure virtual returns (uint96) {
        return 10000;
    }
    /**
     * @dev Sets the royalty information that all ids in this contract will default to.
     *
     * Requirements:
     *
     * - `receiver` cannot be the zero address.
     * - `feeNumerator` cannot be greater than the fee denominator.
     */
    function _setDefaultRoyalty(address receiver, uint96 feeNumerator) internal virtual {
        require(feeNumerator <= _feeDenominator(), "ERC2981: royalty fee will exceed salePrice");
        require(receiver != address(0), "ERC2981: invalid receiver");
        _defaultRoyaltyInfo = RoyaltyInfo(receiver, feeNumerator);
    }
    /**
     * @dev Removes default royalty information.
     */
    function _deleteDefaultRoyalty() internal virtual {
        delete _defaultRoyaltyInfo;
    }
    /**
     * @dev Sets the royalty information for a specific token id, overriding the global default.
     *
     * Requirements:
     *
     * - `tokenId` must be already minted.
     * - `receiver` cannot be the zero address.
     * - `feeNumerator` cannot be greater than the fee denominator.
     */
    function _setTokenRoyalty(
        uint256 tokenId,
        address receiver,
        uint96 feeNumerator
    ) internal virtual {
        require(feeNumerator <= _feeDenominator(), "ERC2981: royalty fee will exceed salePrice");
        require(receiver != address(0), "ERC2981: Invalid parameters");
        _tokenRoyaltyInfo[tokenId] = RoyaltyInfo(receiver, feeNumerator);
    }
    /**
     * @dev Resets royalty information for the token id back to the global default.
     */
    function _resetTokenRoyalty(uint256 tokenId) internal virtual {
        delete _tokenRoyaltyInfo[tokenId];
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)
pragma solidity ^0.8.0;
import "../IERC721.sol";
/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {
    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);
    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() external view returns (string memory);
    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)
pragma solidity ^0.8.0;
/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)
pragma solidity ^0.8.0;
import "../../utils/introspection/IERC165.sol";
/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);
    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);
    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;
    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;
    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;
    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);
    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;
    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)
pragma solidity ^0.8.0;
/**
 * @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 ReentrancyGuard {
    // 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;
    constructor() {
        _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 making 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;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/Pausable.sol)
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);
    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);
    bool private _paused;
    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor() {
        _paused = false;
    }
    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }
    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        require(!paused(), "Pausable: paused");
        _;
    }
    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        require(paused(), "Pausable: not paused");
        _;
    }
    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }
    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (interfaces/IERC721.sol)
pragma solidity ^0.8.0;
import "../token/ERC721/IERC721.sol";
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (interfaces/IERC2981.sol)
pragma solidity ^0.8.0;
import "./IERC165.sol";
/**
 * @dev Interface for the NFT Royalty Standard.
 *
 * A standardized way to retrieve royalty payment information for non-fungible tokens (NFTs) to enable universal
 * support for royalty payments across all NFT marketplaces and ecosystem participants.
 *
 * _Available since v4.5._
 */
interface IERC2981 is IERC165 {
    /**
     * @dev Returns how much royalty is owed and to whom, based on a sale price that may be denominated in any unit of
     * exchange. The royalty amount is denominated and should be payed in that same unit of exchange.
     */
    function royaltyInfo(uint256 tokenId, uint256 salePrice)
        external
        view
        returns (address receiver, uint256 royaltyAmount);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (interfaces/IERC165.sol)
pragma solidity ^0.8.0;
import "../utils/introspection/IERC165.sol";
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_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 {
        _transferOwnership(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");
        _transferOwnership(newOwner);
    }
    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/IAccessControlEnumerable.sol)
pragma solidity ^0.8.0;
import "./IAccessControl.sol";
/**
 * @dev External interface of AccessControlEnumerable declared to support ERC165 detection.
 */
interface IAccessControlEnumerable is IAccessControl {
    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) external view returns (address);
    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) external view returns (uint256);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/IAccessControl.sol)
pragma solidity ^0.8.0;
/**
 * @dev External interface of AccessControl declared to support ERC165 detection.
 */
interface IAccessControl {
    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);
    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {AccessControl-_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);
    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);
    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) external view returns (bool);
    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {AccessControl-_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) external view returns (bytes32);
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) external;
    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) external;
    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) external;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (access/AccessControlEnumerable.sol)
pragma solidity ^0.8.0;
import "./IAccessControlEnumerable.sol";
import "./AccessControl.sol";
import "../utils/structs/EnumerableSet.sol";
/**
 * @dev Extension of {AccessControl} that allows enumerating the members of each role.
 */
abstract contract AccessControlEnumerable is IAccessControlEnumerable, AccessControl {
    using EnumerableSet for EnumerableSet.AddressSet;
    mapping(bytes32 => EnumerableSet.AddressSet) private _roleMembers;
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControlEnumerable).interfaceId || super.supportsInterface(interfaceId);
    }
    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) public view virtual override returns (address) {
        return _roleMembers[role].at(index);
    }
    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) public view virtual override returns (uint256) {
        return _roleMembers[role].length();
    }
    /**
     * @dev Overload {_grantRole} to track enumerable memberships
     */
    function _grantRole(bytes32 role, address account) internal virtual override {
        super._grantRole(role, account);
        _roleMembers[role].add(account);
    }
    /**
     * @dev Overload {_revokeRole} to track enumerable memberships
     */
    function _revokeRole(bytes32 role, address account) internal virtual override {
        super._revokeRole(role, account);
        _roleMembers[role].remove(account);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (access/AccessControl.sol)
pragma solidity ^0.8.0;
import "./IAccessControl.sol";
import "../utils/Context.sol";
import "../utils/Strings.sol";
import "../utils/introspection/ERC165.sol";
/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context, IAccessControl, ERC165 {
    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }
    mapping(bytes32 => RoleData) private _roles;
    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;
    /**
     * @dev Modifier that checks that an account has a specific role. Reverts
     * with a standardized message including the required role.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     *
     * _Available since v4.1._
     */
    modifier onlyRole(bytes32 role) {
        _checkRole(role, _msgSender());
        _;
    }
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControl).interfaceId || super.supportsInterface(interfaceId);
    }
    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view virtual override returns (bool) {
        return _roles[role].members[account];
    }
    /**
     * @dev Revert with a standard message if `account` is missing `role`.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     */
    function _checkRole(bytes32 role, address account) internal view virtual {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(
                        "AccessControl: account ",
                        Strings.toHexString(uint160(account), 20),
                        " is missing role ",
                        Strings.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }
    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view virtual override returns (bytes32) {
        return _roles[role].adminRole;
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _grantRole(role, account);
    }
    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _revokeRole(role, account);
    }
    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been revoked `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) public virtual override {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");
        _revokeRole(role, account);
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     *
     * NOTE: This function is deprecated in favor of {_grantRole}.
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }
    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        bytes32 previousAdminRole = getRoleAdmin(role);
        _roles[role].adminRole = adminRole;
        emit RoleAdminChanged(role, previousAdminRole, adminRole);
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * Internal function without access restriction.
     */
    function _grantRole(bytes32 role, address account) internal virtual {
        if (!hasRole(role, account)) {
            _roles[role].members[account] = true;
            emit RoleGranted(role, account, _msgSender());
        }
    }
    /**
     * @dev Revokes `role` from `account`.
     *
     * Internal function without access restriction.
     */
    function _revokeRole(bytes32 role, address account) internal virtual {
        if (hasRole(role, account)) {
            _roles[role].members[account] = false;
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}
// SPDX-License-Identifier: MIT
// Copyright (c) 2021 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/Pausable.sol";
/// @notice A Pausable contract that can only be toggled by the Owner.
contract OwnerPausable is Ownable, Pausable {
    /// @notice Pauses the contract.
    function pause() public onlyOwner {
        Pausable._pause();
    }
    /// @notice Unpauses the contract.
    function unpause() public onlyOwner {
        Pausable._unpause();
    }
}
// SPDX-License-Identifier: MIT
// Copyright (c) 2021 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;
/**
@notice Provides monotonic increasing and decreasing values, similar to
OpenZeppelin's Counter but (a) limited in direction, and (b) allowing for steps
> 1.
 */
library Monotonic {
    /**
    @notice Holds a value that can only increase.
    @dev The internal value MUST NOT be accessed directly. Instead use current()
    and add().
     */
    struct Increaser {
        uint256 value;
    }
    /// @notice Returns the current value of the Increaser.
    function current(Increaser storage incr) internal view returns (uint256) {
        return incr.value;
    }
    /// @notice Adds x to the Increaser's value.
    function add(Increaser storage incr, uint256 x) internal {
        incr.value += x;
    }
    /**
    @notice Holds a value that can only decrease.
    @dev The internal value MUST NOT be accessed directly. Instead use current()
    and subtract().
     */
    struct Decreaser {
        uint256 value;
    }
    /// @notice Returns the current value of the Decreaser.
    function current(Decreaser storage decr) internal view returns (uint256) {
        return decr.value;
    }
    /// @notice Subtracts x from the Decreaser's value.
    function subtract(Decreaser storage decr, uint256 x) internal {
        decr.value -= x;
    }
}
// SPDX-License-Identifier: MIT
// Copyright (c) 2021 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;
/// @notice A minimal interface describing OpenSea's Wyvern proxy registry.
contract ProxyRegistry {
    mapping(address => OwnableDelegateProxy) public proxies;
}
/**
@dev This pattern of using an empty contract is cargo-culted directly from
OpenSea's example code. TODO: it's likely that the above mapping can be changed
to address => address without affecting anything, but further investigation is
needed (i.e. is there a subtle reason that OpenSea released it like this?).
 */
// solhint-disable-next-line no-empty-blocks
contract OwnableDelegateProxy {
}
// SPDX-License-Identifier: MIT
// Copyright (c) 2021 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;
// Inspired by BaseOpenSea by Simon Fremaux (@dievardump) but without the need
// to pass specific addresses depending on deployment network.
// https://gist.github.com/dievardump/483eb43bc6ed30b14f01e01842e3339b/
import "./ProxyRegistry.sol";
/// @notice Library to achieve gas-free listings on OpenSea.
library OpenSeaGasFreeListing {
    /**
    @notice Returns whether the operator is an OpenSea proxy for the owner, thus
    allowing it to list without the token owner paying gas.
    @dev ERC{721,1155}.isApprovedForAll should be overriden to also check if
    this function returns true.
     */
    function isApprovedForAll(address owner, address operator)
        internal
        view
        returns (bool)
    {
        address proxy = proxyFor(owner);
        return proxy != address(0) && proxy == operator;
    }
    /**
    @notice Returns the OpenSea proxy address for the owner.
     */
    function proxyFor(address owner) internal view returns (address) {
        address registry;
        uint256 chainId;
        assembly {
            chainId := chainid()
            switch chainId
            // Production networks are placed higher to minimise the number of
            // checks performed and therefore reduce gas. By the same rationale,
            // mainnet comes before Polygon as it's more expensive.
            case 1 {
                // mainnet
                registry := 0xa5409ec958c83c3f309868babaca7c86dcb077c1
            }
            case 137 {
                // polygon
                registry := 0x58807baD0B376efc12F5AD86aAc70E78ed67deaE
            }
            case 4 {
                // rinkeby
                registry := 0xf57b2c51ded3a29e6891aba85459d600256cf317
            }
            case 80001 {
                // mumbai
                registry := 0xff7Ca10aF37178BdD056628eF42fD7F799fAc77c
            }
            case 1337 {
                // The geth SimulatedBackend iff used with the ethier
                // openseatest package. This is mocked as a Wyvern proxy as it's
                // more complex than the 0x ones.
                registry := 0xE1a2bbc877b29ADBC56D2659DBcb0ae14ee62071
            }
        }
        // Unlike Wyvern, the registry itself is the proxy for all owners on 0x
        // chains.
        if (registry == address(0) || chainId == 137 || chainId == 80001) {
            return registry;
        }
        return address(ProxyRegistry(registry).proxies(owner));
    }
}
// SPDX-License-Identifier: MIT
// Copyright (c) 2021 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;
import "../utils/Monotonic.sol";
import "../utils/OwnerPausable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "@openzeppelin/contracts/utils/Context.sol";
import "@openzeppelin/contracts/utils/math/Math.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
/**
@notice An abstract contract providing the _purchase() function to:
 - Enforce per-wallet / per-transaction limits
 - Calculate required cost, forwarding to a beneficiary, and refunding extra
 */
abstract contract Seller is OwnerPausable, ReentrancyGuard {
    using Address for address payable;
    using Monotonic for Monotonic.Increaser;
    using Strings for uint256;
    /**
    @dev Note that the address limits are vulnerable to wallet farming.
    @param maxPerAddress Unlimited if zero.
    @param maxPerTex Unlimited if zero.
    @param freeQuota Maximum number that can be purchased free of charge by
    the contract owner.
    @param reserveFreeQuota Whether to excplitly reserve the freeQuota amount
    and not let it be eroded by regular purchases.
    @param lockFreeQuota If true, calls to setSellerConfig() will ignore changes
    to freeQuota. Can be locked after initial setting, but not unlocked. This
    allows a contract owner to commit to a maximum number of reserved items.
    @param lockTotalInventory Similar to lockFreeQuota but applied to
    totalInventory.
    */
    struct SellerConfig {
        uint256 totalInventory;
        uint256 maxPerAddress;
        uint256 maxPerTx;
        uint248 freeQuota;
        bool reserveFreeQuota;
        bool lockFreeQuota;
        bool lockTotalInventory;
    }
    constructor(SellerConfig memory config, address payable _beneficiary) {
        setSellerConfig(config);
        setBeneficiary(_beneficiary);
    }
    /// @notice Configuration of purchase limits.
    SellerConfig public sellerConfig;
    /// @notice Sets the seller config.
    function setSellerConfig(SellerConfig memory config) public onlyOwner {
        require(
            config.totalInventory >= config.freeQuota,
            "Seller: excessive free quota"
        );
        require(
            config.totalInventory >= _totalSold.current(),
            "Seller: inventory < already sold"
        );
        require(
            config.freeQuota >= purchasedFreeOfCharge.current(),
            "Seller: free quota < already used"
        );
        // Overriding the in-memory fields before copying the whole struct, as
        // against writing individual fields, gives a greater guarantee of
        // correctness as the code is simpler to read.
        if (sellerConfig.lockTotalInventory) {
            config.lockTotalInventory = true;
            config.totalInventory = sellerConfig.totalInventory;
        }
        if (sellerConfig.lockFreeQuota) {
            config.lockFreeQuota = true;
            config.freeQuota = sellerConfig.freeQuota;
        }
        sellerConfig = config;
    }
    /// @notice Recipient of revenues.
    address payable public beneficiary;
    /// @notice Sets the recipient of revenues.
    function setBeneficiary(address payable _beneficiary) public onlyOwner {
        beneficiary = _beneficiary;
    }
    /**
    @dev Must return the current cost of a batch of items. This may be constant
    or, for example, decreasing for a Dutch auction or increasing for a bonding
    curve.
    @param n The number of items being purchased.
    @param metadata Arbitrary data, propagated by the call to _purchase() that
    can be used to charge different prices. This value is a uint256 instead of
    bytes as this allows simple passing of a set cost (see
    ArbitraryPriceSeller).
     */
    function cost(uint256 n, uint256 metadata)
        public
        view
        virtual
        returns (uint256);
    /**
    @dev Called by both _purchase() and purchaseFreeOfCharge() after all limits
    have been put in place; must perform all contract-specific sale logic, e.g.
    ERC721 minting. When _handlePurchase() is called, the value returned by
    Seller.totalSold() will be the pre-purchase amount.
    @param to The recipient of the item(s).
    @param n The number of items allowed to be purchased, which MAY be less than
    to the number passed to _purchase() but SHALL be greater than zero.
    @param freeOfCharge Indicates that the call originated from
    purchaseFreeOfCharge() and not _purchase().
    */
    function _handlePurchase(
        address to,
        uint256 n,
        bool freeOfCharge
    ) internal virtual;
    /**
    @notice Tracks total number of items sold by this contract, including those
    purchased free of charge by the contract owner.
     */
    Monotonic.Increaser private _totalSold;
    /// @notice Returns the total number of items sold by this contract.
    function totalSold() public view returns (uint256) {
        return _totalSold.current();
    }
    /**
    @notice Tracks the number of items already bought by an address, regardless
    of transferring out (in the case of ERC721).
    @dev This isn't public as it may be skewed due to differences in msg.sender
    and tx.origin, which it treats in the same way such that
    sum(_bought)>=totalSold().
     */
    mapping(address => uint256) private _bought;
    /**
    @notice Returns min(n, max(extra items addr can purchase)) and reverts if 0.
    @param zeroMsg The message with which to revert on 0 extra.
     */
    function _capExtra(
        uint256 n,
        address addr,
        string memory zeroMsg
    ) internal view returns (uint256) {
        uint256 extra = sellerConfig.maxPerAddress - _bought[addr];
        if (extra == 0) {
            revert(string(abi.encodePacked("Seller: ", zeroMsg)));
        }
        return Math.min(n, extra);
    }
    /// @notice Emitted when a buyer is refunded.
    event Refund(address indexed buyer, uint256 amount);
    /// @notice Emitted on all purchases of non-zero amount.
    event Revenue(
        address indexed beneficiary,
        uint256 numPurchased,
        uint256 amount
    );
    /// @notice Tracks number of items purchased free of charge.
    Monotonic.Increaser private purchasedFreeOfCharge;
    /**
    @notice Allows the contract owner to purchase without payment, within the
    quota enforced by the SellerConfig.
     */
    function purchaseFreeOfCharge(address to, uint256 n)
        public
        onlyOwner
        whenNotPaused
    {
        uint256 freeQuota = sellerConfig.freeQuota;
        n = Math.min(n, freeQuota - purchasedFreeOfCharge.current());
        require(n > 0, "Seller: Free quota exceeded");
        uint256 totalInventory = sellerConfig.totalInventory;
        n = Math.min(n, totalInventory - _totalSold.current());
        require(n > 0, "Seller: Sold out");
        _handlePurchase(to, n, true);
        _totalSold.add(n);
        purchasedFreeOfCharge.add(n);
        assert(_totalSold.current() <= totalInventory);
        assert(purchasedFreeOfCharge.current() <= freeQuota);
    }
    /**
    @notice Convenience function for calling _purchase() with empty costMetadata
    when unneeded.
     */
    function _purchase(address to, uint256 requested) internal virtual {
        _purchase(to, requested, 0);
    }
    /**
    @notice Enforces all purchase limits (counts and costs) before calling
    _handlePurchase(), after which the received funds are disbursed to the
    beneficiary, less any required refunds.
    @param to The final recipient of the item(s).
    @param requested The number of items requested for purchase, which MAY be
    reduced when passed to _handlePurchase().
    @param costMetadata Arbitrary data, propagated in the call to cost(), to be
    optionally used in determining the price.
     */
    function _purchase(
        address to,
        uint256 requested,
        uint256 costMetadata
    ) internal nonReentrant whenNotPaused {
        /**
         * ##### CHECKS
         */
        SellerConfig memory config = sellerConfig;
        uint256 n = config.maxPerTx == 0
            ? requested
            : Math.min(requested, config.maxPerTx);
        uint256 maxAvailable;
        uint256 sold;
        if (config.reserveFreeQuota) {
            maxAvailable = config.totalInventory - config.freeQuota;
            sold = _totalSold.current() - purchasedFreeOfCharge.current();
        } else {
            maxAvailable = config.totalInventory;
            sold = _totalSold.current();
        }
        n = Math.min(n, maxAvailable - sold);
        require(n > 0, "Seller: Sold out");
        if (config.maxPerAddress > 0) {
            bool alsoLimitSender = _msgSender() != to;
            // solhint-disable-next-line avoid-tx-origin
            bool alsoLimitOrigin = tx.origin != _msgSender() && tx.origin != to;
            n = _capExtra(n, to, "Buyer limit");
            if (alsoLimitSender) {
                n = _capExtra(n, _msgSender(), "Sender limit");
            }
            if (alsoLimitOrigin) {
                // solhint-disable-next-line avoid-tx-origin
                n = _capExtra(n, tx.origin, "Origin limit");
            }
            _bought[to] += n;
            if (alsoLimitSender) {
                _bought[_msgSender()] += n;
            }
            if (alsoLimitOrigin) {
                // solhint-disable-next-line avoid-tx-origin
                _bought[tx.origin] += n;
            }
        }
        uint256 _cost = cost(n, costMetadata);
        if (msg.value < _cost) {
            revert(
                string(
                    abi.encodePacked(
                        "Seller: Costs ",
                        (_cost / 1e9).toString(),
                        " GWei"
                    )
                )
            );
        }
        /**
         * ##### EFFECTS
         */
        _handlePurchase(to, n, false);
        _totalSold.add(n);
        assert(_totalSold.current() <= config.totalInventory);
        /**
         * ##### INTERACTIONS
         */
        // Ideally we'd be using a PullPayment here, but the user experience is
        // poor when there's a variable cost or the number of items purchased
        // has been capped. We've addressed reentrancy with both a nonReentrant
        // modifier and the checks, effects, interactions pattern.
        if (_cost > 0) {
            beneficiary.sendValue(_cost);
            emit Revenue(beneficiary, n, _cost);
        }
        if (msg.value > _cost) {
            address payable reimburse = payable(_msgSender());
            uint256 refund = msg.value - _cost;
            // Using Address.sendValue() here would mask the revertMsg upon
            // reentrancy, but we want to expose it to allow for more precise
            // testing. This otherwise uses the exact same pattern as
            // Address.sendValue().
            // solhint-disable-next-line avoid-low-level-calls
            (bool success, bytes memory returnData) = reimburse.call{
                value: refund
            }("");
            // Although `returnData` will have a spurious prefix, all we really
            // care about is that it contains the ReentrancyGuard reversion
            // message so we can check in the tests.
            require(success, string(returnData));
            emit Refund(reimburse, refund);
        }
    }
}
// SPDX-License-Identifier: MIT
// Copyright (c) 2021 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;
import "./Seller.sol";
/// @notice A Seller with fixed per-item price.
abstract contract FixedPriceSeller is Seller {
    constructor(
        uint256 _price,
        Seller.SellerConfig memory sellerConfig,
        address payable _beneficiary
    ) Seller(sellerConfig, _beneficiary) {
        setPrice(_price);
    }
    /**
    @notice The fixed per-item price.
    @dev Fixed as in not changing with time nor number of items, but not a
    constant.
     */
    uint256 public price;
    /// @notice Sets the per-item price.
    function setPrice(uint256 _price) public onlyOwner {
        price = _price;
    }
    /**
    @notice Override of Seller.cost() with fixed price.
    @dev The second parameter, metadata propagated from the call to _purchase(),
    is ignored.
     */
    function cost(uint256 n, uint256) public view override returns (uint256) {
        return n * price;
    }
}
// SPDX-License-Identifier: MIT
// Copyright (c) 2022 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;
import "@openzeppelin/contracts/interfaces/IERC721.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/utils/structs/BitMaps.sol";
/**
@notice Allows holders of ERC721 tokens to redeem rights to some claim; for
example, the right to mint a token of some other collection.
*/
library ERC721Redeemer {
    using BitMaps for BitMaps.BitMap;
    using Strings for uint256;
    /**
    @notice Storage value to track already-claimed redemptions for a specific
    token collection.
     */
    struct Claims {
        /**
        @dev This field MUST NOT be considered part of the public API. Instead,
        prefer `using ERC721Redeemer for ERC721Redeemer.Claims` and utilise the
        provided functions.
         */
        mapping(uint256 => uint256) _total;
    }
    /**
    @notice Storage value to track already-claimed redemptions for a specific
    token collection, given that there is only a single claim allowed per
    tokenId.
     */
    struct SingleClaims {
        /**
        @dev This field MUST NOT be considered part of the public API. Instead,
        prefer `using ERC721Redeemer for ERC721Redeemer.SingleClaims` and
        utilise the provided functions.
         */
        BitMaps.BitMap _claimed;
    }
    /**
    @notice Emitted when a token's claim is redeemed.
     */
    event Redemption(
        IERC721 indexed token,
        address indexed redeemer,
        uint256 tokenId,
        uint256 n
    );
    /**
    @notice Checks that the redeemer is allowed to redeem the claims for the
    tokenIds by being either the owner or approved address for all tokenIds, and
    updates the Claims to reflect this.
    @dev For more efficient gas usage, recurring values in tokenIds SHOULD be
    adjacent to one another as this will batch expensive operations. The
    simplest way to achieve this is by sorting tokenIds.
    @param tokenIds The token IDs for which the claims are being redeemed. If
    maxAllowance > 1 then identical tokenIds can be passed more than once; see
    dev comments.
    @return The number of redeemed claims; either 0 or tokenIds.length;
     */
    function redeem(
        Claims storage claims,
        uint256 maxAllowance,
        address redeemer,
        IERC721 token,
        uint256[] calldata tokenIds
    ) internal returns (uint256) {
        if (maxAllowance == 0 || tokenIds.length == 0) {
            return 0;
        }
        // See comment for `endSameId`.
        bool multi = maxAllowance > 1;
        for (
            uint256 i = 0;
            i < tokenIds.length; /* note increment at end */
        ) {
            uint256 tokenId = tokenIds[i];
            requireOwnerOrApproved(token, tokenId, redeemer);
            uint256 n = 1;
            if (multi) {
                // If allowed > 1 we can save on expensive operations like
                // checking ownership / remaining allowance by batching equal
                // tokenIds. The algorithm assumes that equal IDs are adjacent
                // in the array.
                uint256 endSameId;
                for (
                    endSameId = i + 1;
                    endSameId < tokenIds.length &&
                        tokenIds[endSameId] == tokenId;
                    endSameId++
                ) {} // solhint-disable-line no-empty-blocks
                n = endSameId - i;
            }
            claims._total[tokenId] += n;
            if (claims._total[tokenId] > maxAllowance) {
                revertWithTokenId(
                    "ERC721Redeemer: over allowance for",
                    tokenId
                );
            }
            i += n;
            emit Redemption(token, redeemer, tokenId, n);
        }
        return tokenIds.length;
    }
    /**
    @notice Checks that the redeemer is allowed to redeem the single claim for
    each of the tokenIds by being either the owner or approved address for all
    tokenIds, and updates the SingleClaims to reflect this.
    @param tokenIds The token IDs for which the claims are being redeemed. Only
    a single claim can be made against a tokenId.
    @return The number of redeemed claims; either 0 or tokenIds.length;
     */
    function redeem(
        SingleClaims storage claims,
        address redeemer,
        IERC721 token,
        uint256[] calldata tokenIds
    ) internal returns (uint256) {
        if (tokenIds.length == 0) {
            return 0;
        }
        for (uint256 i = 0; i < tokenIds.length; i++) {
            uint256 tokenId = tokenIds[i];
            requireOwnerOrApproved(token, tokenId, redeemer);
            if (claims._claimed.get(tokenId)) {
                revertWithTokenId(
                    "ERC721Redeemer: over allowance for",
                    tokenId
                );
            }
            claims._claimed.set(tokenId);
            emit Redemption(token, redeemer, tokenId, 1);
        }
        return tokenIds.length;
    }
    /**
    @dev Reverts if neither the owner nor approved for the tokenId.
     */
    function requireOwnerOrApproved(
        IERC721 token,
        uint256 tokenId,
        address redeemer
    ) private view {
        if (
            token.ownerOf(tokenId) != redeemer &&
            token.getApproved(tokenId) != redeemer
        ) {
            revertWithTokenId(
                "ERC721Redeemer: not approved nor owner of",
                tokenId
            );
        }
    }
    /**
    @notice Reverts with the concatenation of revertMsg and tokenId.toString().
    @dev Used to save gas by constructing the revert message only as required,
    instead of passing it to require().
     */
    function revertWithTokenId(string memory revertMsg, uint256 tokenId)
        private
        pure
    {
        revert(string(abi.encodePacked(revertMsg, " ", tokenId.toString())));
    }
    /**
    @notice Returns the number of claimed redemptions for the token.
     */
    function claimed(Claims storage claims, uint256 tokenId)
        internal
        view
        returns (uint256)
    {
        return claims._total[tokenId];
    }
    /**
    @notice Returns whether the token has had a claim made against it.
     */
    function claimed(SingleClaims storage claims, uint256 tokenId)
        internal
        view
        returns (bool)
    {
        return claims._claimed.get(tokenId);
    }
}
// SPDX-License-Identifier: MIT
// Copyright (c) 2021 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;
import "../thirdparty/opensea/OpenSeaGasFreeListing.sol";
import "erc721a/contracts/ERC721A.sol";
/// @notice Pre-approval of OpenSea proxies for gas-less listing
/// @dev This wrapper allows users to revoke the pre-approval of their
/// associated proxy and emits the corresponding events. This is necessary for
/// external tools to index approvals correctly and inform the user.
/// @dev The pre-approval is triggered on a per-wallet basis during the first
/// transfer transactions. It will only be enabled for wallets with an existing
/// proxy. Not having a proxy incurs a gas overhead.
/// @dev This wrapper optimizes for the following scenario:
/// - The majority of users already have a wyvern proxy
/// - Most of them want to transfer tokens via wyvern exchanges
abstract contract ERC721APreApproval is ERC721A {
    /// @dev It is important that Active remains at first position, since this
    /// is the scenario that we are trying to optimize for.
    enum State {
        Active,
        Inactive
    }
    /// @notice The state of the pre-approval for a given owner
    mapping(address => State) private state;
    /// @dev Returns true if either standard `isApprovedForAll()` or if the
    /// `operator` is the OpenSea proxy for the `owner` provided the
    /// pre-approval is active.
    function isApprovedForAll(address owner, address operator)
        public
        view
        virtual
        override
        returns (bool)
    {
        if (super.isApprovedForAll(owner, operator)) {
            return true;
        }
        return
            state[owner] == State.Active &&
            OpenSeaGasFreeListing.isApprovedForAll(owner, operator);
    }
    /// @dev Uses the standard `setApprovalForAll` or toggles the pre-approval
    /// state if `operator` is the OpenSea proxy for the sender.
    function setApprovalForAll(address operator, bool approved)
        public
        virtual
        override
    {
        address owner = _msgSender();
        if (operator == OpenSeaGasFreeListing.proxyFor(owner)) {
            state[owner] = approved ? State.Active : State.Inactive;
            emit ApprovalForAll(owner, operator, approved);
        } else {
            super.setApprovalForAll(operator, approved);
        }
    }
    /// @dev Checks if the receiver has an existing proxy. If not, the
    /// pre-approval is disabled.
    function _beforeTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual override {
        super._beforeTokenTransfers(from, to, startTokenId, quantity);
        // Exclude burns and inactive pre-approvals
        if (to == address(0) || state[to] == State.Inactive) {
            return;
        }
        address operator = OpenSeaGasFreeListing.proxyFor(to);
        // Disable if `to` has no proxy
        if (operator == address(0)) {
            state[to] = State.Inactive;
            return;
        }
        // Avoid emitting unnecessary events.
        if (balanceOf(to) == 0) {
            emit ApprovalForAll(to, operator, true);
        }
    }
}
// SPDX-License-Identifier: MIT
// Copyright (c) 2022 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;
import "./ERC721APreApproval.sol";
import "../utils/OwnerPausable.sol";
/**
@notice An ERC721A contract with common functionality:
 - OpenSea gas-free listings
 - Pausable with toggling functions exposed to Owner only
 */
contract ERC721ACommon is ERC721APreApproval, OwnerPausable {
    constructor(string memory name, string memory symbol)
        ERC721A(name, symbol)
    {} // solhint-disable-line no-empty-blocks
    /// @notice Requires that the token exists.
    modifier tokenExists(uint256 tokenId) {
        require(ERC721A._exists(tokenId), "ERC721ACommon: Token doesn't exist");
        _;
    }
    /// @notice Requires that msg.sender owns or is approved for the token.
    modifier onlyApprovedOrOwner(uint256 tokenId) {
        require(
            _ownershipOf(tokenId).addr == _msgSender() ||
                getApproved(tokenId) == _msgSender(),
            "ERC721ACommon: Not approved nor owner"
        );
        _;
    }
    function _beforeTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual override {
        require(!paused(), "ERC721ACommon: paused");
        super._beforeTokenTransfers(from, to, startTokenId, quantity);
    }
    /// @notice Overrides supportsInterface as required by inheritance.
    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override(ERC721A)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }
}
// SPDX-License-Identifier: MIT
// Copyright (c) 2021 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;
import "@openzeppelin/contracts/access/Ownable.sol";
/**
@notice ERC721 extension that overrides the OpenZeppelin _baseURI() function to
return a prefix that can be set by the contract owner.
 */
contract BaseTokenURI is Ownable {
    /// @notice Base token URI used as a prefix by tokenURI().
    string public baseTokenURI;
    constructor(string memory _baseTokenURI) {
        setBaseTokenURI(_baseTokenURI);
    }
    /// @notice Sets the base token URI prefix.
    function setBaseTokenURI(string memory _baseTokenURI) public onlyOwner {
        baseTokenURI = _baseTokenURI;
    }
    /**
    @notice Concatenates and returns the base token URI and the token ID without
    any additional characters (e.g. a slash).
    @dev This requires that an inheriting contract that also inherits from OZ's
    ERC721 will have to override both contracts; although we could simply
    require that users implement their own _baseURI() as here, this can easily
    be forgotten and the current approach guides them with compiler errors. This
    favours the latter half of "APIs should be easy to use and hard to misuse"
    from https://www.infoq.com/articles/API-Design-Joshua-Bloch/.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return baseTokenURI;
    }
}
// SPDX-License-Identifier: MIT
// Copyright (c) 2022 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/structs/EnumerableSet.sol";
/**
@title SignerManager
@notice Manges addition and removal of a core set of addresses from which
valid ECDSA signatures can be accepted; see SignatureChecker.
 */
contract SignerManager is Ownable {
    using EnumerableSet for EnumerableSet.AddressSet;
    /**
    @dev Addresses from which signatures can be accepted.
     */
    EnumerableSet.AddressSet internal signers;
    /**
    @notice Add an address to the set of accepted signers.
     */
    function addSigner(address signer) external onlyOwner {
        signers.add(signer);
    }
    /**
    @notice Remove an address previously added with addSigner().
     */
    function removeSigner(address signer) external onlyOwner {
        signers.remove(signer);
    }
}
// SPDX-License-Identifier: MIT
// Copyright (c) 2021 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;
import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
import "@openzeppelin/contracts/utils/structs/EnumerableSet.sol";
/**
@title SignatureChecker
@notice Additional functions for EnumerableSet.Addresset that require a valid
ECDSA signature of a standardized message, signed by any member of the set.
 */
library SignatureChecker {
    using EnumerableSet for EnumerableSet.AddressSet;
    /**
    @notice Requires that the message has not been used previously and that the
    recovered signer is contained in the signers AddressSet.
    @dev Convenience wrapper for message generation + signature verification
    + marking message as used
    @param signers Set of addresses from which signatures are accepted.
    @param usedMessages Set of already-used messages.
    @param signature ECDSA signature of message.
     */
    function requireValidSignature(
        EnumerableSet.AddressSet storage signers,
        bytes memory data,
        bytes calldata signature,
        mapping(bytes32 => bool) storage usedMessages
    ) internal {
        bytes32 message = generateMessage(data);
        require(
            !usedMessages[message],
            "SignatureChecker: Message already used"
        );
        usedMessages[message] = true;
        requireValidSignature(signers, message, signature);
    }
    /**
    @notice Requires that the message has not been used previously and that the
    recovered signer is contained in the signers AddressSet.
    @dev Convenience wrapper for message generation + signature verification.
     */
    function requireValidSignature(
        EnumerableSet.AddressSet storage signers,
        bytes memory data,
        bytes calldata signature
    ) internal view {
        bytes32 message = generateMessage(data);
        requireValidSignature(signers, message, signature);
    }
    /**
    @notice Requires that the message has not been used previously and that the
    recovered signer is contained in the signers AddressSet.
    @dev Convenience wrapper for message generation from address +
    signature verification.
     */
    function requireValidSignature(
        EnumerableSet.AddressSet storage signers,
        address a,
        bytes calldata signature
    ) internal view {
        bytes32 message = generateMessage(abi.encodePacked(a));
        requireValidSignature(signers, message, signature);
    }
    /**
    @notice Common validator logic, checking if the recovered signer is
    contained in the signers AddressSet.
    */
    function validSignature(
        EnumerableSet.AddressSet storage signers,
        bytes32 message,
        bytes calldata signature
    ) internal view returns (bool) {
        return signers.contains(ECDSA.recover(message, signature));
    }
    /**
    @notice Requires that the recovered signer is contained in the signers
    AddressSet.
    @dev Convenience wrapper that reverts if the signature validation fails.
    */
    function requireValidSignature(
        EnumerableSet.AddressSet storage signers,
        bytes32 message,
        bytes calldata signature
    ) internal view {
        require(
            validSignature(signers, message, signature),
            "SignatureChecker: Invalid signature"
        );
    }
    /**
    @notice Generates a message for a given data input that will be signed
    off-chain using ECDSA.
    @dev For multiple data fields, a standard concatenation using 
    `abi.encodePacked` is commonly used to build data.
     */
    function generateMessage(bytes memory data)
        internal
        pure
        returns (bytes32)
    {
        return ECDSA.toEthSignedMessageHash(data);
    }
}