// File: contracts/MonkeyPoly.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.11;

import "@openzeppelin/contracts/utils/Address.sol";
import "@openzeppelin/contracts/utils/Context.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/Pausable.sol";
import "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
import "./ERC721A.sol";

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contract MonkeyPoly is ERC721A, Ownable, Pausable {
	using Address for address;
	using Strings for uint256;
	using MerkleProof for bytes32[];

	address proxyRegistryAddress;

	//the merkle root
	bytes32 public root = 0x21a69ae93781ffea397668022e64c09ba2760422692a9d74a8fd2e87deb26f71;

	string public _contractBaseURI = "https://unreveal.monkeypoly.com/";
	string public _contractURI = "https://monkeypoly.com/contract_uri/contract_uri.json";

	uint256 public tokenPrice = 0.03 ether; //price per token

	mapping(address => uint256) public usedAddresses; //used addresses for whitelist

	bool public locked; //baseURI & contractURI lock
	uint256 public maxSupply = 9999; //tokenIDs start from 0

	uint256 public whitelistStartTime = block.timestamp - 1; //TODO: change to real;
	uint256 public publicSaleStartTime = block.timestamp - 1; //TODO: change to real;

	constructor() ERC721A("MonkeyPoly", "MonkeyPoly", 5) {
		_safeMint(msg.sender, 1); //mints 1 nft to the owner for configuring opensea
	}

	/**
	 * @dev whitelist buy
	 */
	function whitelistBuy(
		uint256 qty,
		uint256 tokenId,
		bytes32[] calldata proof
	) external payable whenNotPaused {
		require(qty <= 2, "max 2");
		require(tokenPrice * qty == msg.value, "exact amount needed");
		require(usedAddresses[msg.sender] + qty <= 2, "max per wallet reached");
		require(block.timestamp > whitelistStartTime, "not live");
		require(isTokenValid(msg.sender, tokenId, proof), "invalid merkle proof");

		usedAddresses[msg.sender] += qty;

		_safeMint(msg.sender, qty);
	}

	/**
	 * @dev everyone can mint freely
	 */
	function buy(uint256 qty) external payable whenNotPaused {
		require(tokenPrice * qty == msg.value, "exact amount needed");
		require(qty < 6, "max 5 at once");
		require(totalSupply() + qty <= maxSupply, "out of stock");
		require(block.timestamp > publicSaleStartTime, "not live");

		_safeMint(msg.sender, qty);
	}

	/**
	 * @dev can airdrop tokens
	 */
	function adminMint(address to, uint256 qty) external onlyOwner {
		require(totalSupply() + qty <= maxSupply, "out of stock");
		_safeMint(to, qty);
	}

	/**
	 * @dev verification function for merkle root
	 */
	function isTokenValid(
		address _to,
		uint256 _tokenId,
		bytes32[] memory _proof
	) public view returns (bool) {
		// construct Merkle tree leaf from the inputs supplied
		bytes32 leaf = keccak256(abi.encodePacked(_to, _tokenId));
		// verify the proof supplied, and return the verification result
		return _proof.verify(root, leaf);
	}

	function setMerkleRoot(bytes32 _root) external onlyOwner {
		root = _root;
	}

	//----------------------------------
	//----------- other code -----------
	//----------------------------------
	function tokensOfOwner(address _owner) external view returns (uint256[] memory) {
		uint256 tokenCount = balanceOf(_owner);
		if (tokenCount == 0) {
			return new uint256[](0);
		} else {
			uint256[] memory result = new uint256[](tokenCount);
			uint256 index;
			for (index = 0; index < tokenCount; index++) {
				result[index] = tokenOfOwnerByIndex(_owner, index);
			}
			return result;
		}
	}

	function tokenURI(uint256 _tokenId) public view override returns (string memory) {
		require(_exists(_tokenId), "ERC721Metadata: URI query for nonexistent token");
		return string(abi.encodePacked(_contractBaseURI, _tokenId.toString(), ".json"));
	}

	function setBaseURI(string memory newBaseURI) external onlyOwner {
		require(!locked, "locked functions");
		_contractBaseURI = newBaseURI;
	}

	function setContractURI(string memory newuri) external onlyOwner {
		require(!locked, "locked functions");
		_contractURI = newuri;
	}

	function contractURI() public view returns (string memory) {
		return _contractURI;
	}

	function reclaimERC20(IERC20 erc20Token) external onlyOwner {
		erc20Token.transfer(msg.sender, erc20Token.balanceOf(address(this)));
	}

	function reclaimERC721(IERC721 erc721Token, uint256 id) external onlyOwner {
		erc721Token.safeTransferFrom(address(this), msg.sender, id);
	}

	function setWhitelistStartTime(uint256 newTime) external onlyOwner {
		whitelistStartTime = newTime;
	}

	function setPublicSaleStartTime(uint256 newTime) external onlyOwner {
		publicSaleStartTime = newTime;
	}

	//change the price per token
	function setCost(uint256 newPrice) external onlyOwner {
		tokenPrice = newPrice;
	}

	//change the max supply
	function setmaxMintAmount(uint256 newMaxSupply) public onlyOwner {
		maxSupply = newMaxSupply;
	}

	//blocks staking but doesn't block unstaking / claiming
	function setPaused(bool _setPaused) public onlyOwner {
		return (_setPaused) ? _pause() : _unpause();
	}

	//sets the opensea proxy
	function setProxyRegistry(address _newRegistry) external onlyOwner {
		proxyRegistryAddress = _newRegistry;
	}

	// and for the eternity!
	function lockBaseURIandContractURI() external onlyOwner {
		locked = true;
	}

	// earnings withdrawal
	function withdraw() public payable onlyOwner {
		uint256 _total_owner = address(this).balance;

		(bool all1, ) = payable(0xed6f9E7d3A94141E28cA5D1905d2EA9F085D00FA).call{
			value: (_total_owner * 1) / 3
		}(""); //l
		require(all1);
		(bool all2, ) = payable(0x318cbB40Fdaf1A2Ab545B957518cb95D7c18ED32).call{
			value: (_total_owner * 1) / 3
		}(""); //sc
		require(all2);
		(bool all3, ) = payable(0x831C6bF9562791480802055Eb51311f6EedCA783).call{
			value: (_total_owner * 1) / 3
		}(""); //sp
		require(all3);
	}

	/**
	 * Override isApprovedForAll to whitelist user's OpenSea proxy accounts to enable gas-less listings.
	 */
	function isApprovedForAll(address owner, address operator) public view override returns (bool) {
		// Whitelist OpenSea proxy contract for easy trading.
		ProxyRegistry proxyRegistry = ProxyRegistry(proxyRegistryAddress);
		if (address(proxyRegistry.proxies(owner)) == operator) {
			return true;
		}
		return super.isApprovedForAll(owner, operator);
	}
}

//opensea removal of approvals
contract OwnableDelegateProxy {

}

contract ProxyRegistry {
	mapping(address => OwnableDelegateProxy) public proxies;
}

// File: @openzeppelin/contracts/utils/Address.sol



// 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);
            }
        }
    }
}

// File: @openzeppelin/contracts/utils/Context.sol



// 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;
    }
}

// File: @openzeppelin/contracts/utils/Strings.sol



// 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);
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// 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);
}

// File: @openzeppelin/contracts/access/Ownable.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);
    }
}

// File: @openzeppelin/contracts/security/Pausable.sol



// 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());
    }
}

// File: @openzeppelin/contracts/utils/cryptography/MerkleProof.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/cryptography/MerkleProof.sol)

pragma solidity ^0.8.0;

/**
 * @dev These functions deal with verification of Merkle Trees proofs.
 *
 * The proofs can be generated using the JavaScript library
 * https://github.com/miguelmota/merkletreejs[merkletreejs].
 * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
 *
 * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
 */
library MerkleProof {
    /**
     * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
     * defined by `root`. For this, a `proof` must be provided, containing
     * sibling hashes on the branch from the leaf to the root of the tree. Each
     * pair of leaves and each pair of pre-images are assumed to be sorted.
     */
    function verify(
        bytes32[] memory proof,
        bytes32 root,
        bytes32 leaf
    ) internal pure returns (bool) {
        return processProof(proof, leaf) == root;
    }

    /**
     * @dev Returns the rebuilt hash obtained by traversing a Merklee tree up
     * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
     * hash matches the root of the tree. When processing the proof, the pairs
     * of leafs & pre-images are assumed to be sorted.
     *
     * _Available since v4.4._
     */
    function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
        bytes32 computedHash = leaf;
        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];
            if (computedHash <= proofElement) {
                // Hash(current computed hash + current element of the proof)
                computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
            }
        }
        return computedHash;
    }
}

// File: contracts/ERC721A.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.11;

import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.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";
import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";

contract ERC721A is Context, ERC165, IERC721, IERC721Metadata, IERC721Enumerable {
	using Address for address;
	using Strings for uint256;

	struct TokenOwnership {
		address addr;
		uint64 startTimestamp;
	}

	struct AddressData {
		uint128 balance;
		uint128 numberMinted;
	}

	uint256 private currentIndex = 0;

	address private burned = address(1);

	uint256 internal immutable maxBatchSize;

	// 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) private _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;

	/**
	 * @dev
	 * `maxBatchSize` refers to how much a minter can mint at a time.
	 */
	constructor(
		string memory name_,
		string memory symbol_,
		uint256 maxBatchSize_
	) {
		require(maxBatchSize_ > 0, "ERC721A: max batch size must be nonzero");
		_name = name_;
		_symbol = symbol_;
		maxBatchSize = maxBatchSize_;
	}

	/**
	 * @dev See {IERC721Enumerable-totalSupply}.
	 */
	function totalSupply() public view override returns (uint256) {
		return currentIndex;
	}

	/**
	 * @dev See {IERC721Enumerable-tokenByIndex}.
	 */
	function tokenByIndex(uint256 index) public view override returns (uint256) {
		require(index < totalSupply(), "ERC721A: global index out of bounds");
		return index;
	}

	/**
	 * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
	 * This read function is O(totalSupply). If calling from a separate contract, be sure to test gas first.
	 * It may also degrade with extremely large collection sizes (e.g >> 10000), test for your use case.
	 */
	function tokenOfOwnerByIndex(address owner, uint256 index)
		public
		view
		override
		returns (uint256)
	{
		require(index < balanceOf(owner), "ERC721A: owner index out of bounds");
		uint256 numMintedSoFar = totalSupply();
		uint256 tokenIdsIdx = 0;
		address currOwnershipAddr = address(0);
		for (uint256 i = 0; i < numMintedSoFar; i++) {
			TokenOwnership memory ownership = _ownerships[i];
			if (ownership.addr != address(0)) {
				currOwnershipAddr = ownership.addr;
			}
			if (currOwnershipAddr == owner) {
				if (tokenIdsIdx == index) {
					return i;
				}
				tokenIdsIdx++;
			}
		}
		revert("ERC721A: unable to get token of owner by index");
	}

	/**
	 * @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 ||
			interfaceId == type(IERC721Enumerable).interfaceId ||
			super.supportsInterface(interfaceId);
	}

	/**
	 * @dev See {IERC721-balanceOf}.
	 */
	function balanceOf(address owner) public view override returns (uint256) {
		require(owner != address(0), "ERC721A: balance query for the zero address");
		return uint256(_addressData[owner].balance);
	}

	function _numberMinted(address owner) internal view returns (uint256) {
		require(owner != address(0), "ERC721A: number minted query for the zero address");
		return uint256(_addressData[owner].numberMinted);
	}

	function ownershipOf(uint256 tokenId) internal view returns (TokenOwnership memory) {
		require(_exists(tokenId), "ERC721A: owner query for nonexistent token");

		uint256 lowestTokenToCheck;
		if (tokenId >= maxBatchSize) {
			lowestTokenToCheck = tokenId - maxBatchSize + 1;
		}

		for (uint256 curr = tokenId; curr >= lowestTokenToCheck; curr--) {
			TokenOwnership memory ownership = _ownerships[curr];
			if (ownership.addr != address(0)) {
				return ownership;
			}
		}

		revert("ERC721A: unable to determine the owner of token");
	}

	/**
	 * @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) {
		require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");

		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);
		require(to != owner, "ERC721A: approval to current owner");

		require(
			_msgSender() == owner || isApprovedForAll(owner, _msgSender()),
			"ERC721A: approve caller is not owner nor approved for all"
		);

		_approve(to, tokenId, owner);
	}

	/**
	 * @dev See {IERC721-getApproved}.
	 */
	function getApproved(uint256 tokenId) public view override returns (address) {
		require(_exists(tokenId), "ERC721A: approved query for nonexistent token");

		return _tokenApprovals[tokenId];
	}

	/**
	 * @dev See {IERC721-setApprovalForAll}.
	 */
	function setApprovalForAll(address operator, bool approved) public override {
		require(operator != _msgSender(), "ERC721A: approve to caller");

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

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

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

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

	/**
	 * @dev See {IERC721-safeTransferFrom}.
	 */
	function safeTransferFrom(
		address from,
		address to,
		uint256 tokenId,
		bytes memory _data
	) public override {
		_transfer(from, to, tokenId);
		require(
			_checkOnERC721Received(from, to, tokenId, _data),
			"ERC721A: transfer to non ERC721Receiver implementer"
		);
	}

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

	function _safeMint(address to, uint256 quantity) internal {
		_safeMint(to, quantity, "");
	}

	/**
	 * @dev Mints `quantity` tokens and transfers them to `to`.
	 *
	 * Requirements:
	 *
	 * - `to` cannot be the zero address.
	 * - `quantity` cannot be larger than the max batch size.
	 *
	 * Emits a {Transfer} event.
	 */
	function _safeMint(
		address to,
		uint256 quantity,
		bytes memory _data
	) internal {
		uint256 startTokenId = currentIndex;
		require(to != address(0), "ERC721A: mint to the zero address");
		// We know if the first token in the batch doesn't exist, the other ones don't as well, because of serial ordering.
		require(!_exists(startTokenId), "ERC721A: token already minted");
		require(quantity <= maxBatchSize, "ERC721A: quantity to mint too high");

		_beforeTokenTransfers(address(0), to, startTokenId, quantity);

		AddressData memory addressData = _addressData[to];
		_addressData[to] = AddressData(
			addressData.balance + uint128(quantity),
			addressData.numberMinted + uint128(quantity)
		);
		_ownerships[startTokenId] = TokenOwnership(to, uint64(block.timestamp));

		uint256 updatedIndex = startTokenId;

		for (uint256 i = 0; i < quantity; i++) {
			emit Transfer(address(0), to, updatedIndex);
			require(
				_checkOnERC721Received(address(0), to, updatedIndex, _data),
				"ERC721A: transfer to non ERC721Receiver implementer"
			);
			updatedIndex++;
		}

		currentIndex = updatedIndex;
		_afterTokenTransfers(address(0), to, startTokenId, quantity);
	}

	//change the ownership of a token. limited to the quantities put in require!
	// function _changeOwnership(uint256 tokenId, address to) internal {
	// 	TokenOwnership memory prevOwnership = ownershipOf(tokenId);
	// 	_addressData[prevOwnership.addr].balance -= 1;
	// 	_ownerships[tokenId] = TokenOwnership(burned, uint64(block.timestamp));

	// 	_beforeTokenTransfers(address(0), to, tokenId, 1);

	// 	AddressData memory addressData = _addressData[to];
	// 	_addressData[to] = AddressData(addressData.balance + 1, addressData.numberMinted + 1);
	// 	_ownerships[tokenId] = TokenOwnership(to, uint64(block.timestamp));

	// 	emit Transfer(address(0), to, tokenId);
	// 	_afterTokenTransfers(address(0), to, tokenId, 1);
	// }

	/**
	 * @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);

		bool isApprovedOrOwner = (_msgSender() == prevOwnership.addr ||
			getApproved(tokenId) == _msgSender() ||
			isApprovedForAll(prevOwnership.addr, _msgSender()));

		require(isApprovedOrOwner, "ERC721A: transfer caller is not owner nor approved");

		require(prevOwnership.addr == from, "ERC721A: transfer from incorrect owner");
		require(to != address(0), "ERC721A: transfer to the zero address");

		_beforeTokenTransfers(from, to, tokenId, 1);

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

		_addressData[from].balance -= 1;
		_addressData[to].balance += 1;
		_ownerships[tokenId] = TokenOwnership(to, 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;
		if (_ownerships[nextTokenId].addr == address(0)) {
			if (_exists(nextTokenId)) {
				_ownerships[nextTokenId] = TokenOwnership(prevOwnership.addr, prevOwnership.startTimestamp);
			}
		}

		emit Transfer(from, to, tokenId);
		_afterTokenTransfers(from, to, tokenId, 1);
	}

	/**
	 * @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);
	}

	uint256 public nextOwnerToExplicitlySet = 0;

	/**
	 * @dev Explicitly set `owners` to eliminate loops in future calls of ownerOf().
	 */
	function _setOwnersExplicit(uint256 quantity) internal {
		uint256 oldNextOwnerToSet = nextOwnerToExplicitlySet;
		require(quantity > 0, "quantity must be nonzero");
		uint256 endIndex = oldNextOwnerToSet + quantity - 1;
		if (endIndex > currentIndex - 1) {
			endIndex = currentIndex - 1;
		}
		// We know if the last one in the group exists, all in the group exist, due to serial ordering.
		require(_exists(endIndex), "not enough minted yet for this cleanup");
		for (uint256 i = oldNextOwnerToSet; i <= endIndex; i++) {
			if (_ownerships[i].addr == address(0)) {
				TokenOwnership memory ownership = ownershipOf(i);
				_ownerships[i] = TokenOwnership(ownership.addr, ownership.startTimestamp);
			}
		}
		nextOwnerToExplicitlySet = endIndex + 1;
	}

	/**
	 * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
	 * The call is not executed if the target address is not a contract.
	 *
	 * @param from address representing the previous owner of the given token ID
	 * @param to target address that will receive the tokens
	 * @param tokenId uint256 ID of the token to be transferred
	 * @param _data bytes optional data to send along with the call
	 * @return bool whether the call correctly returned the expected magic value
	 */
	function _checkOnERC721Received(
		address from,
		address to,
		uint256 tokenId,
		bytes memory _data
	) private returns (bool) {
		if (to.isContract()) {
			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("ERC721A: transfer to non ERC721Receiver implementer");
				} else {
					assembly {
						revert(add(32, reason), mload(reason))
					}
				}
			}
		} else {
			return true;
		}
	}

	/**
	 * @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
	 *
	 * 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`.
	 */
	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.
	 *
	 * 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` and `to` are never both zero.
	 */
	function _afterTokenTransfers(
		address from,
		address to,
		uint256 startTokenId,
		uint256 quantity
	) internal virtual {}
}

// File: @openzeppelin/contracts/token/ERC721/IERC721.sol



// 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;
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol



// 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);
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Enumerable.sol)

pragma solidity ^0.8.0;

import "../IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {
    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

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

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

// File: @openzeppelin/contracts/utils/introspection/ERC165.sol



// 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;
    }
}

// File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol



// 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);
}

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol



// 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);
}