ETH Price: $2,521.58 (+0.89%)

Transaction Decoder

Block:
14267381 at Feb-24-2022 07:14:47 AM +UTC
Transaction Fee:
0.002763687921898365 ETH $6.97
Gas Used:
30,415 Gas / 90.865951731 Gwei

Account State Difference:

  Address   Before After State Difference Code
0x00000005...887136a95 409.08 Eth0 Eth409.08
(Hiveon Pool)
10,824.291230778886915263 Eth10,824.291261193886915263 Eth0.000030415
0x705b9c9a...262F2565b
(SeKira: Deployer)
0.811923076097500631 Eth
Nonce: 8
409.889159388175602266 Eth
Nonce: 9
409.077236312078101635

Execution Trace

SeKira.CALL( )
  • ETH 409.08 SeKira: Deployer.CALL( )
    // SPDX-License-Identifier: MIT
    pragma solidity ^0.8.4;
    import "@openzeppelin/contracts/access/Ownable.sol";
    import "@openzeppelin/contracts/interfaces/IERC2981.sol";
    import "@openzeppelin/contracts/utils/cryptography/draft-EIP712.sol";
    import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
    import "./ERC721A.sol";
    contract SeKira is ERC721A, EIP712, IERC2981, Ownable {
        using Strings for uint256;
        using ECDSA for bytes32;
        uint256 private constant PRICE_MULTIPLIER = 0.0001 ether;
        uint256 private constant FEE_DENOMINATOR = 10000;
        bytes32 private constant PRESALE_HASH = keccak256("presaleMint(address receiver)");
        bytes32 private constant RAFFLE_SALE_HASH = keccak256("raffleMint(address receiver)");
        string private constant SIGN_PREFIX = "\\x19Ethereum Signed Message:\
    32";
        uint8 public constant PRESALE_RAFFLE_MAX_MINT = 2;
        uint8 public constant RAFFLE_SALE_MAX_MINT = 2;
        uint8 public constant PUBLIC_SALE_MAX_MINT = 3;
        struct Config {
            // Immutable config
            uint16 maxSupply;
            uint16 devReservedSupply;
            // Mutable config
            uint16 presalePrice;
            uint16 raffleSalePrice;
            uint16 publicSalePrice;
            uint16 royaltyRate;
            // Mutable state
            uint16 devMinted;
            bool isPresaleActive;
            bool isRaffleSaleActive;
            bool isPublicSaleActive;
        }
        Config public _config;
        string public _uriPrefix;
        constructor(Config memory config, string memory uriPrefix) ERC721A("SeKira", "SKRA") EIP712("SeKira", "1") {
            require(
                config.maxSupply >= config.devReservedSupply,
                "SeKira: maxSupply must not be smaller then supply reserved for devs"
            );
            require(config.royaltyRate <= FEE_DENOMINATOR, "SeKira: invalid royalty fee rate");
            config.devMinted = 0;
            _config = config;
            _uriPrefix = uriPrefix;
        }
        modifier verifySig(
            bytes32 mintMethodHash,
            bytes32 r,
            bytes32 s,
            uint8 v
        ) {
            bytes32 funcCallDigest = keccak256(abi.encode(mintMethodHash, msg.sender));
            bytes32 typedDataDigest = _domainSeparatorV4().toTypedDataHash(funcCallDigest);
            bytes32 digest = keccak256(abi.encodePacked(SIGN_PREFIX, typedDataDigest));
            require(ecrecover(digest, v, r, s) == address(owner()), "SeKira: invalid signature");
            _;
        }
        modifier botDefender() {
            require(tx.origin == msg.sender, "SeKira: bots, get out");
            _;
        }
        function ensureSupply(Config memory config, uint8 mintAmount) internal view {
            uint256 publicSupply = uint256(config.maxSupply - config.devReservedSupply);
            require(_currentIndex + mintAmount <= publicSupply, "SeKira: exceed max supply");
        }
        function ensureSufficientValue(uint16 unitPrice, uint8 mintAmount) internal view {
            require(uint256(unitPrice) * PRICE_MULTIPLIER * mintAmount == msg.value, "SeKira: incorrect value");
        }
        function sekiraPresaleMint(
            uint8 amount,
            uint8 v,
            bytes32 r,
            bytes32 s
        ) external payable botDefender verifySig(PRESALE_HASH, r, s, v) {
            Config memory config = _config;
            require(config.isPresaleActive, "SeKira: presale is not started");
            ensureSupply(config, amount);
            ensureSufficientValue(config.presalePrice, amount);
            require(incrementPresaleMinted(amount) <= PRESALE_RAFFLE_MAX_MINT, "SeKira: exceed presale mint limit");
            _safeMint(msg.sender, amount);
        }
        function sekiraRaffleSaleMint(
            uint8 amount,
            uint8 v,
            bytes32 r,
            bytes32 s
        ) external payable botDefender verifySig(RAFFLE_SALE_HASH, r, s, v) {
            Config memory config = _config;
            require(config.isRaffleSaleActive, "SeKira: raffle sale mint is not started");
            ensureSupply(config, amount);
            ensureSufficientValue(config.raffleSalePrice, amount);
            require(incrementRaffleMinted(amount) <= RAFFLE_SALE_MAX_MINT, "SeKira: exceed raffle sale mint limit");
            _safeMint(msg.sender, amount);
        }
        function sekiraPublicMint(uint8 amount) external payable botDefender {
            Config memory config = _config;
            require(config.isPublicSaleActive, "SeKira: public sale is not started");
            ensureSupply(config, amount);
            ensureSufficientValue(config.publicSalePrice, amount);
            require(incrementPublicMinted(amount) <= PUBLIC_SALE_MAX_MINT, "SeKira: exceed public sale mint limit");
            _safeMint(msg.sender, amount);
        }
        // ::
        // :: Aux operation
        // ::
        // :: Memory layout (64-bits space):
        // ::     | High bits...| PresaleMinted(8bit) | RaffleMinted(8bit) | PublicMinted(8bit) |
        // ::
        function _aux(address minter) public view returns (uint64) {
            return _getAux(minter);
        }
        function incrementMintedNumberInAux(
            uint64 mask,
            uint8 offset,
            uint8 amount
        ) internal returns (uint8) {
            uint64 aux = _getAux(msg.sender);
            uint8 newMintedAmount = uint8((aux >> offset) & 0xFF) + amount;
            _setAux(msg.sender, (aux & mask) | (uint64(newMintedAmount) << offset));
            return newMintedAmount;
        }
        function _presaleMinted(address minter) public view returns (uint8) {
            return uint8((_getAux(minter) >> 16) & 0xFF);
        }
        function incrementPresaleMinted(uint8 amount) internal returns (uint8) {
            return incrementMintedNumberInAux(0x00FFFF, 16, amount);
        }
        function _raffleSaleMinted(address minter) public view returns (uint8) {
            return uint8((_getAux(minter) >> 8) & 0xFF);
        }
        function incrementRaffleMinted(uint8 amount) internal returns (uint8) {
            return incrementMintedNumberInAux(0xFF00FF, 8, amount);
        }
        function _publicSaleMinted(address minter) public view returns (uint8) {
            return uint8(_getAux(minter) & 0xFF);
        }
        function incrementPublicMinted(uint8 amount) internal returns (uint8) {
            return incrementMintedNumberInAux(0xFFFF00, 0, amount);
        }
        // ::
        // :: Admin operation
        // ::
        function sekiraDevMint(address to, uint16 amount) external onlyOwner {
            Config memory config = _config;
            require(amount + config.devMinted <= config.devReservedSupply, "SeKira: exceed dev reserved supply");
            _config.devMinted += amount;
            _safeMint(to, amount);
        }
        function setURIPrefix(string calldata uriPrefix) external onlyOwner {
            _uriPrefix = uriPrefix;
        }
        function setPrices(
            uint16 presalePrice,
            uint16 raffleSalePrice,
            uint16 publicSalePrice
        ) external onlyOwner {
            Config memory config = _config;
            config.presalePrice = presalePrice;
            config.raffleSalePrice = raffleSalePrice;
            config.publicSalePrice = publicSalePrice;
            _config = config;
        }
        function setRoyaltyRate(uint16 royaltyRate) external onlyOwner {
            require(royaltyRate <= FEE_DENOMINATOR, "SeKira: invalid royalty fee rate");
            _config.royaltyRate = royaltyRate;
        }
        function setPresaleState(bool newState) external onlyOwner {
            if (newState) {
                require(!_config.isPublicSaleActive, "SeKira: public sale is started");
            }
            _config.isPresaleActive = newState;
        }
        function setRaffleSaleState(bool newState) external onlyOwner {
            if (newState) {
                require(!_config.isPublicSaleActive, "SeKira: public sale is started");
            }
            _config.isRaffleSaleActive = newState;
        }
        function setPublicSaleState(bool newState) external onlyOwner {
            if (newState) {
                require(!_config.isPresaleActive, "SeKira: presale is started");
                require(!_config.isRaffleSaleActive, "SeKira: raffle sale is started");
            }
            _config.isPublicSaleActive = newState;
        }
        function withdraw() external onlyOwner {
            Address.sendValue(payable(msg.sender), address(this).balance);
        }
        // ::
        // :: EIP Implementations
        // ::
        function tokenURI(uint256 tokenId) public view override returns (string memory) {
            if (!_exists(tokenId)) revert URIQueryForNonexistentToken();
            return string(abi.encodePacked(_uriPrefix, tokenId.toString(), ".json"));
        }
        function supportsInterface(bytes4 interfaceId) public view override(ERC721A, IERC165) returns (bool) {
            return interfaceId == type(IERC2981).interfaceId || ERC721A.supportsInterface(interfaceId);
        }
        function royaltyInfo(uint256 tokenId, uint256 salePrice)
            external
            view
            override
            returns (address receiver, uint256 royaltyAmount)
        {
            require(_exists(tokenId), "SeKira: query nonexistent token");
            return (owner(), (salePrice * _config.royaltyRate) / FEE_DENOMINATOR);
        }
    }
    // 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 (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 (utils/cryptography/draft-EIP712.sol)
    pragma solidity ^0.8.0;
    import "./ECDSA.sol";
    /**
     * @dev https://eips.ethereum.org/EIPS/eip-712[EIP 712] is a standard for hashing and signing of typed structured data.
     *
     * The encoding specified in the EIP is very generic, and such a generic implementation in Solidity is not feasible,
     * thus this contract does not implement the encoding itself. Protocols need to implement the type-specific encoding
     * they need in their contracts using a combination of `abi.encode` and `keccak256`.
     *
     * This contract implements the EIP 712 domain separator ({_domainSeparatorV4}) that is used as part of the encoding
     * scheme, and the final step of the encoding to obtain the message digest that is then signed via ECDSA
     * ({_hashTypedDataV4}).
     *
     * The implementation of the domain separator was designed to be as efficient as possible while still properly updating
     * the chain id to protect against replay attacks on an eventual fork of the chain.
     *
     * NOTE: This contract implements the version of the encoding known as "v4", as implemented by the JSON RPC method
     * https://docs.metamask.io/guide/signing-data.html[`eth_signTypedDataV4` in MetaMask].
     *
     * _Available since v3.4._
     */
    abstract contract EIP712 {
        /* solhint-disable var-name-mixedcase */
        // Cache the domain separator as an immutable value, but also store the chain id that it corresponds to, in order to
        // invalidate the cached domain separator if the chain id changes.
        bytes32 private immutable _CACHED_DOMAIN_SEPARATOR;
        uint256 private immutable _CACHED_CHAIN_ID;
        address private immutable _CACHED_THIS;
        bytes32 private immutable _HASHED_NAME;
        bytes32 private immutable _HASHED_VERSION;
        bytes32 private immutable _TYPE_HASH;
        /* solhint-enable var-name-mixedcase */
        /**
         * @dev Initializes the domain separator and parameter caches.
         *
         * The meaning of `name` and `version` is specified in
         * https://eips.ethereum.org/EIPS/eip-712#definition-of-domainseparator[EIP 712]:
         *
         * - `name`: the user readable name of the signing domain, i.e. the name of the DApp or the protocol.
         * - `version`: the current major version of the signing domain.
         *
         * NOTE: These parameters cannot be changed except through a xref:learn::upgrading-smart-contracts.adoc[smart
         * contract upgrade].
         */
        constructor(string memory name, string memory version) {
            bytes32 hashedName = keccak256(bytes(name));
            bytes32 hashedVersion = keccak256(bytes(version));
            bytes32 typeHash = keccak256(
                "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
            );
            _HASHED_NAME = hashedName;
            _HASHED_VERSION = hashedVersion;
            _CACHED_CHAIN_ID = block.chainid;
            _CACHED_DOMAIN_SEPARATOR = _buildDomainSeparator(typeHash, hashedName, hashedVersion);
            _CACHED_THIS = address(this);
            _TYPE_HASH = typeHash;
        }
        /**
         * @dev Returns the domain separator for the current chain.
         */
        function _domainSeparatorV4() internal view returns (bytes32) {
            if (address(this) == _CACHED_THIS && block.chainid == _CACHED_CHAIN_ID) {
                return _CACHED_DOMAIN_SEPARATOR;
            } else {
                return _buildDomainSeparator(_TYPE_HASH, _HASHED_NAME, _HASHED_VERSION);
            }
        }
        function _buildDomainSeparator(
            bytes32 typeHash,
            bytes32 nameHash,
            bytes32 versionHash
        ) private view returns (bytes32) {
            return keccak256(abi.encode(typeHash, nameHash, versionHash, block.chainid, address(this)));
        }
        /**
         * @dev Given an already https://eips.ethereum.org/EIPS/eip-712#definition-of-hashstruct[hashed struct], this
         * function returns the hash of the fully encoded EIP712 message for this domain.
         *
         * This hash can be used together with {ECDSA-recover} to obtain the signer of a message. For example:
         *
         * ```solidity
         * bytes32 digest = _hashTypedDataV4(keccak256(abi.encode(
         *     keccak256("Mail(address to,string contents)"),
         *     mailTo,
         *     keccak256(bytes(mailContents))
         * )));
         * address signer = ECDSA.recover(digest, signature);
         * ```
         */
        function _hashTypedDataV4(bytes32 structHash) internal view virtual returns (bytes32) {
            return ECDSA.toTypedDataHash(_domainSeparatorV4(), structHash);
        }
    }
    // 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
    // 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/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";
    error ApprovalCallerNotOwnerNorApproved();
    error ApprovalQueryForNonexistentToken();
    error ApproveToCaller();
    error ApprovalToCurrentOwner();
    error BalanceQueryForZeroAddress();
    error MintedQueryForZeroAddress();
    error BurnedQueryForZeroAddress();
    error AuxQueryForZeroAddress();
    error MintToZeroAddress();
    error MintZeroQuantity();
    error OwnerIndexOutOfBounds();
    error OwnerQueryForNonexistentToken();
    error TokenIndexOutOfBounds();
    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 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_;
        }
        /**
         * @dev See {IERC721Enumerable-totalSupply}.
         */
        function totalSupply() public view returns (uint256) {
            // Counter underflow is impossible as _burnCounter cannot be incremented
            // more than _currentIndex times
            unchecked {
                return _currentIndex - _burnCounter;
            }
        }
        /**
         * @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) {
            if (owner == address(0)) revert MintedQueryForZeroAddress();
            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) {
            if (owner == address(0)) revert BurnedQueryForZeroAddress();
            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) {
            if (owner == address(0)) revert AuxQueryForZeroAddress();
            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 {
            if (owner == address(0)) revert AuxQueryForZeroAddress();
            _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 (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 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 (!_checkOnERC721Received(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 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;
                for (uint256 i; i < quantity; i++) {
                    emit Transfer(address(0), to, updatedIndex);
                    if (safe && !_checkOnERC721Received(address(0), to, updatedIndex, _data)) {
                        revert TransferToNonERC721ReceiverImplementer();
                    }
                    updatedIndex++;
                }
                _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);
            bool isApprovedOrOwner = (_msgSender() == prevOwnership.addr ||
                isApprovedForAll(prevOwnership.addr, _msgSender()) ||
                getApproved(tokenId) == _msgSender());
            if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
            if (prevOwnership.addr != from) revert TransferFromIncorrectOwner();
            if (to == address(0)) revert TransferToZeroAddress();
            _beforeTokenTransfers(from, to, tokenId, 1);
            // Clear approvals from the previous owner
            _approve(address(0), tokenId, prevOwnership.addr);
            // 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;
                _ownerships[tokenId].addr = to;
                _ownerships[tokenId].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;
                if (_ownerships[nextTokenId].addr == address(0)) {
                    // This will suffice for checking _exists(nextTokenId),
                    // as a burned slot cannot contain the zero address.
                    if (nextTokenId < _currentIndex) {
                        _ownerships[nextTokenId].addr = prevOwnership.addr;
                        _ownerships[nextTokenId].startTimestamp = prevOwnership.startTimestamp;
                    }
                }
            }
            emit Transfer(from, to, tokenId);
            _afterTokenTransfers(from, to, tokenId, 1);
        }
        /**
         * @dev Destroys `tokenId`.
         * The approval is cleared when the token is burned.
         *
         * Requirements:
         *
         * - `tokenId` must exist.
         *
         * Emits a {Transfer} event.
         */
        function _burn(uint256 tokenId) internal virtual {
            TokenOwnership memory prevOwnership = ownershipOf(tokenId);
            _beforeTokenTransfers(prevOwnership.addr, address(0), tokenId, 1);
            // Clear approvals from the previous owner
            _approve(address(0), tokenId, prevOwnership.addr);
            // 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[prevOwnership.addr].balance -= 1;
                _addressData[prevOwnership.addr].numberBurned += 1;
                // Keep track of who burned the token, and the timestamp of burning.
                _ownerships[tokenId].addr = prevOwnership.addr;
                _ownerships[tokenId].startTimestamp = uint64(block.timestamp);
                _ownerships[tokenId].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;
                if (_ownerships[nextTokenId].addr == address(0)) {
                    // This will suffice for checking _exists(nextTokenId),
                    // as a burned slot cannot contain the zero address.
                    if (nextTokenId < _currentIndex) {
                        _ownerships[nextTokenId].addr = prevOwnership.addr;
                        _ownerships[nextTokenId].startTimestamp = prevOwnership.startTimestamp;
                    }
                }
            }
            emit Transfer(prevOwnership.addr, address(0), tokenId);
            _afterTokenTransfers(prevOwnership.addr, 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 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 TransferToNonERC721ReceiverImplementer();
                    } 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.
         * 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/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 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 (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/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 (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/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/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 (last updated v4.5.0) (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);
        /**
         * @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);
    }
    // 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 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;
        }
    }