// File: src/contracts/goat/GoatV2.sol



// SPDX-License-Identifier: UNLICENSED

pragma solidity ^0.8.6;

import "./Goat.sol";

contract GoatV2 is Goat {
  constructor(
    string memory _name,
    string memory _symbol,
    string memory _initBaseURI,
    address _signer
  ) Goat(_name, _symbol, _initBaseURI, _signer) {}

  function sendToken(
    uint256 _tokenId,
    address _receiver,
    uint256 _price,
    bytes memory _signature
  ) external payable override {
    address owner = ownerOf(_tokenId);
    require(
      isSignatureValid(owner, _receiver, _tokenId, _price, sendNonce[_tokenId], _signature),
      "Goat: invalid signature"
    );
    require(msg.value >= _price, "Goat: price is higher than the amount of ETH sent");

    safeTransferFromWithoutCheckingNesting(owner, _receiver, _tokenId);

    if (_price != 0) {
      (bool success, ) = address(owner).call{value: _price}("");
      require(success, "Unable to send ETH to owner of token");

      if (_price < msg.value) {
        (success, ) = address(_receiver).call{value: msg.value - _price}("");
        require(success, "Unable to send ETH to buyer");
      }
    }

    sendNonce[_tokenId] += 1;
  }
}

// File: src/contracts/goat/Goat.sol



// SPDX-License-Identifier: UNLICENSED

pragma solidity ^0.8.6;

import "@divergencetech/ethier/contracts/erc721/BaseTokenURI.sol";
import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
import "./ERC721AQueryableGoat.sol";

contract Goat is ERC721AQueryableGoat, BaseTokenURI {
  using Strings for uint256;
  using ECDSA for bytes32;

  address public signatureSigner;

  mapping(uint256 => bool) public isTokenNotNested; // false == nesting, true == not nested
  mapping(uint256 => uint256) public sendNonce;
  mapping(address => uint256) public mintNonce;
  mapping(address => bool) public isAdmin;

  event Nested(uint256 indexed tokenId);
  event Unnested(uint256 indexed tokenId);

  modifier isAdminOrOwner(address _address) {
    require(isAdmin[_address] || _address == owner(), "Goat: Only admin or owner can call this function");
    _;
  }

  constructor(
    string memory _name,
    string memory _symbol,
    string memory _initBaseURI,
    address _signer
  ) ERC721AGoat(_name, _symbol) BaseTokenURI(_initBaseURI) {
    signatureSigner = _signer;
  }

  function _baseURI() internal view override(BaseTokenURI, ERC721AGoat) returns (string memory) {
    return BaseTokenURI._baseURI();
  }

  function tokenURI(uint256 tokenId) public view override(ERC721AGoat) returns (string memory) {
    require(_exists(tokenId), "ERC721Metadata: tokenURI queried for nonexistent token");
    string memory currentBaseURI = Goat._baseURI();
    return
      bytes(currentBaseURI).length > 0 ? string(abi.encodePacked(currentBaseURI, tokenId.toString(), ".json")) : "";
  }

  function mint(uint256 _mintPrice, bytes memory _signature) external payable {
    require(
      isSignatureValid(address(0), _msgSender(), 0, _mintPrice, mintNonce[_msgSender()], _signature),
      "Goat: Invalid signature"
    );
    require(msg.value >= _mintPrice, "Goat: price is higher than the amount of ETH sent");

    if (_mintPrice < msg.value) {
      (bool success, ) = address(_msgSender()).call{value: msg.value - _mintPrice}("");
      require(success, "Unable to send ETH to minter");
    }

    _mint(_msgSender(), 1);
    mintNonce[_msgSender()] += 1;
  }

  function sendToken(
    uint256 _tokenId,
    address _receiver,
    uint256 _price,
    bytes memory _signature
  ) external payable virtual {
    address owner = ownerOf(_tokenId);
    require(
      isSignatureValid(owner, _receiver, _tokenId, _price, sendNonce[_tokenId], _signature),
      "Goat: invalid signature"
    );
    require(msg.value >= _price, "Goat: price is higher than the amount of ETH sent");

    if (owner != _msgSender()) {
      _tokenApprovals[_tokenId] = _msgSender();
    }

    safeTransferFromWithoutCheckingNesting(owner, _receiver, _tokenId);

    if (_price != 0) {
      (bool success, ) = address(owner).call{value: _price}("");
      require(success, "Unable to send ETH to owner of token");

      if (_price < msg.value) {
        (success, ) = address(_receiver).call{value: msg.value - _price}("");
        require(success, "Unable to send ETH to buyer");
      }
    }

    sendNonce[_tokenId] += 1;
  }

  /**
    @dev Block transfers while nesting.
     */
  function _beforeTokenTransfers(
    address from,
    address,
    uint256 startTokenId,
    uint256 quantity
  ) internal view override {
    uint256 tokenId = startTokenId;
    for (uint256 i = tokenId; i < (tokenId + quantity); ++i) {
      require(from == address(0) || isTokenNotNested[i], "Goat: token is nesting");
    }
  }

  // ONLY ADMIN FUNCTION
  function toggleNesting(uint256 _tokenId) external isAdminOrOwner(_msgSender()) {
    bool isNesting = !isTokenNotNested[_tokenId];
    isTokenNotNested[_tokenId] = !isTokenNotNested[_tokenId];
    if (isNesting == false) {
      emit Nested(_tokenId);
    } else {
      emit Unnested(_tokenId);
    }
  }

  function adminMint(address[] calldata _tos, bool[] calldata _isNested) external isAdminOrOwner(_msgSender()) {
    require(_tos.length == _isNested.length, "Goat: entries length not match");
    for (uint256 i; i < _tos.length; i++) {
      uint256 tokenId = _nextTokenId();
      _mint(_tos[i], 1);
      if (_isNested[i] == false) {
        isTokenNotNested[i] = true;
      }
      emit Nested(tokenId);
    }
  }

  // ONLY OWNER FUNCTION
  function ownerMint(
    address[] calldata _tos,
    uint256[] calldata _amounts,
    bool[] calldata _isNested
  ) external onlyOwner {
    require(_tos.length == _amounts.length && _tos.length == _isNested.length, "Goat: entries length not match");
    for (uint256 i; i < _tos.length; i++) {
      uint256 tokenId = _nextTokenId();
      _mint(_tos[i], _amounts[i]);
      if (_isNested[i] == false) {
        for (uint256 j = tokenId; j < (tokenId + _amounts[i]); ++j) {
          isTokenNotNested[j] = true;
        }
      }
      emit Nested(tokenId);
    }
  }

  function assignAdmins(address[] calldata _admins) external onlyOwner {
    for (uint256 i = 0; i < _admins.length; i++) {
      isAdmin[_admins[i]] = true;
    }
  }

  function revokeAdmins(address[] calldata _admins) external onlyOwner {
    for (uint256 i = 0; i < _admins.length; i++) {
      isAdmin[_admins[i]] = false;
    }
  }

  function setSignatureSigner(address _signer) external onlyOwner {
    signatureSigner = _signer;
  }

  function withdraw(address _receiver) external onlyOwner {
    (bool success, ) = address(_receiver).call{value: address(this).balance}("");
    require(success, "Unable to withdraw balance");
  }

  function isSignatureValid(
    address _from,
    address _to,
    uint256 _tokenId,
    uint256 _price,
    uint256 _nonce,
    bytes memory signature
  ) internal view returns (bool) {
    bytes32 hash = keccak256(abi.encodePacked(_from, _to, _tokenId, _price, _nonce, address(this)));
    hash = keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
    return signatureSigner == hash.recover(signature);
  }
}

// File: @divergencetech/ethier/contracts/erc721/BaseTokenURI.sol



// SPDX-License-Identifier: MIT
// Copyright (c) 2021 the ethier authors (github.com/divergencetech/ethier)
pragma solidity >=0.8.0 <0.9.0;

import "@openzeppelin/contracts/access/Ownable.sol";

/**
@notice ERC721 extension that overrides the OpenZeppelin _baseURI() function to
return a prefix that can be set by the contract owner.
 */
contract BaseTokenURI is Ownable {
    /// @notice Base token URI used as a prefix by tokenURI().
    string public baseTokenURI;

    constructor(string memory _baseTokenURI) {
        setBaseTokenURI(_baseTokenURI);
    }

    /// @notice Sets the base token URI prefix.
    function setBaseTokenURI(string memory _baseTokenURI) public onlyOwner {
        baseTokenURI = _baseTokenURI;
    }

    /**
    @notice Concatenates and returns the base token URI and the token ID without
    any additional characters (e.g. a slash).
    @dev This requires that an inheriting contract that also inherits from OZ's
    ERC721 will have to override both contracts; although we could simply
    require that users implement their own _baseURI() as here, this can easily
    be forgotten and the current approach guides them with compiler errors. This
    favours the latter half of "APIs should be easy to use and hard to misuse"
    from https://www.infoq.com/articles/API-Design-Joshua-Bloch/.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return baseTokenURI;
    }
}

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



// 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:\n32", 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:\n", 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));
    }
}

// File: src/contracts/goat/ERC721AQueryableGoat.sol



// SPDX-License-Identifier: MIT
// ERC721A Contracts v4.0.0
// Creator: Chiru Labs

pragma solidity ^0.8.4;

import "./IERC721AQueryableGoat.sol";
import "./ERC721AGoat.sol";

/**
 * @title ERC721A Queryable
 * @dev ERC721A subclass with convenience query functions.
 */
abstract contract ERC721AQueryableGoat is ERC721AGoat, IERC721AQueryableGoat {
  /**
   * @dev Returns the `TokenOwnership` struct at `tokenId` without reverting.
   *
   * If the `tokenId` is out of bounds:
   *   - `addr` = `address(0)`
   *   - `startTimestamp` = `0`
   *   - `burned` = `false`
   *
   * If the `tokenId` is burned:
   *   - `addr` = `<Address of owner before token was burned>`
   *   - `startTimestamp` = `<Timestamp when token was burned>`
   *   - `burned = `true`
   *
   * Otherwise:
   *   - `addr` = `<Address of owner>`
   *   - `startTimestamp` = `<Timestamp of start of ownership>`
   *   - `burned = `false`
   */
  function explicitOwnershipOf(uint256 tokenId) public view override returns (TokenOwnership memory) {
    TokenOwnership memory ownership;
    if (tokenId < _startTokenId() || tokenId >= _nextTokenId()) {
      return ownership;
    }
    ownership = _ownershipAt(tokenId);
    if (ownership.burned) {
      return ownership;
    }
    return _ownershipOf(tokenId);
  }

  /**
   * @dev Returns an array of `TokenOwnership` structs at `tokenIds` in order.
   * See {ERC721AQueryable-explicitOwnershipOf}
   */
  function explicitOwnershipsOf(uint256[] memory tokenIds) external view override returns (TokenOwnership[] memory) {
    unchecked {
      uint256 tokenIdsLength = tokenIds.length;
      TokenOwnership[] memory ownerships = new TokenOwnership[](tokenIdsLength);
      for (uint256 i; i != tokenIdsLength; ++i) {
        ownerships[i] = explicitOwnershipOf(tokenIds[i]);
      }
      return ownerships;
    }
  }

  /**
   * @dev Returns an array of token IDs owned by `owner`,
   * in the range [`start`, `stop`)
   * (i.e. `start <= tokenId < stop`).
   *
   * This function allows for tokens to be queried if the collection
   * grows too big for a single call of {ERC721AQueryable-tokensOfOwner}.
   *
   * Requirements:
   *
   * - `start` < `stop`
   */
  function tokensOfOwnerIn(
    address owner,
    uint256 start,
    uint256 stop
  ) external view override returns (uint256[] memory) {
    unchecked {
      if (start >= stop) revert InvalidQueryRange();
      uint256 tokenIdsIdx;
      uint256 stopLimit = _nextTokenId();
      // Set `start = max(start, _startTokenId())`.
      if (start < _startTokenId()) {
        start = _startTokenId();
      }
      // Set `stop = min(stop, stopLimit)`.
      if (stop > stopLimit) {
        stop = stopLimit;
      }
      uint256 tokenIdsMaxLength = balanceOf(owner);
      // Set `tokenIdsMaxLength = min(balanceOf(owner), stop - start)`,
      // to cater for cases where `balanceOf(owner)` is too big.
      if (start < stop) {
        uint256 rangeLength = stop - start;
        if (rangeLength < tokenIdsMaxLength) {
          tokenIdsMaxLength = rangeLength;
        }
      } else {
        tokenIdsMaxLength = 0;
      }
      uint256[] memory tokenIds = new uint256[](tokenIdsMaxLength);
      if (tokenIdsMaxLength == 0) {
        return tokenIds;
      }
      // We need to call `explicitOwnershipOf(start)`,
      // because the slot at `start` may not be initialized.
      TokenOwnership memory ownership = explicitOwnershipOf(start);
      address currOwnershipAddr;
      // If the starting slot exists (i.e. not burned), initialize `currOwnershipAddr`.
      // `ownership.address` will not be zero, as `start` is clamped to the valid token ID range.
      if (!ownership.burned) {
        currOwnershipAddr = ownership.addr;
      }
      for (uint256 i = start; i != stop && tokenIdsIdx != tokenIdsMaxLength; ++i) {
        ownership = _ownershipAt(i);
        if (ownership.burned) {
          continue;
        }
        if (ownership.addr != address(0)) {
          currOwnershipAddr = ownership.addr;
        }
        if (currOwnershipAddr == owner) {
          tokenIds[tokenIdsIdx++] = i;
        }
      }
      // Downsize the array to fit.
      assembly {
        mstore(tokenIds, tokenIdsIdx)
      }
      return tokenIds;
    }
  }

  /**
   * @dev Returns an array of token IDs owned by `owner`.
   *
   * This function scans the ownership mapping and is O(totalSupply) in complexity.
   * It is meant to be called off-chain.
   *
   * See {ERC721AQueryable-tokensOfOwnerIn} for splitting the scan into
   * multiple smaller scans if the collection is large enough to cause
   * an out-of-gas error (10K pfp collections should be fine).
   */
  function tokensOfOwner(address owner) external view override returns (uint256[] memory) {
    unchecked {
      uint256 tokenIdsIdx;
      address currOwnershipAddr;
      uint256 tokenIdsLength = balanceOf(owner);
      uint256[] memory tokenIds = new uint256[](tokenIdsLength);
      TokenOwnership memory ownership;
      for (uint256 i = _startTokenId(); tokenIdsIdx != tokenIdsLength; ++i) {
        ownership = _ownershipAt(i);
        if (ownership.burned) {
          continue;
        }
        if (ownership.addr != address(0)) {
          currOwnershipAddr = ownership.addr;
        }
        if (currOwnershipAddr == owner) {
          tokenIds[tokenIdsIdx++] = i;
        }
      }
      return tokenIds;
    }
  }
}

// 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/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: src/contracts/goat/IERC721AQueryableGoat.sol



// SPDX-License-Identifier: MIT
// ERC721A Contracts v4.0.0
// Creator: Chiru Labs

pragma solidity ^0.8.4;

import "erc721a/contracts/IERC721A.sol";

/**
 * @dev Interface of an ERC721AQueryable compliant contract.
 */
interface IERC721AQueryableGoat is IERC721A {
  /**
   * Invalid query range (`start` >= `stop`).
   */
  error InvalidQueryRange();

  /**
   * @dev Returns the `TokenOwnership` struct at `tokenId` without reverting.
   *
   * If the `tokenId` is out of bounds:
   *   - `addr` = `address(0)`
   *   - `startTimestamp` = `0`
   *   - `burned` = `false`
   *
   * If the `tokenId` is burned:
   *   - `addr` = `<Address of owner before token was burned>`
   *   - `startTimestamp` = `<Timestamp when token was burned>`
   *   - `burned = `true`
   *
   * Otherwise:
   *   - `addr` = `<Address of owner>`
   *   - `startTimestamp` = `<Timestamp of start of ownership>`
   *   - `burned = `false`
   */
  function explicitOwnershipOf(uint256 tokenId) external view returns (TokenOwnership memory);

  /**
   * @dev Returns an array of `TokenOwnership` structs at `tokenIds` in order.
   * See {ERC721AQueryable-explicitOwnershipOf}
   */
  function explicitOwnershipsOf(uint256[] memory tokenIds) external view returns (TokenOwnership[] memory);

  /**
   * @dev Returns an array of token IDs owned by `owner`,
   * in the range [`start`, `stop`)
   * (i.e. `start <= tokenId < stop`).
   *
   * This function allows for tokens to be queried if the collection
   * grows too big for a single call of {ERC721AQueryable-tokensOfOwner}.
   *
   * Requirements:
   *
   * - `start` < `stop`
   */
  function tokensOfOwnerIn(
    address owner,
    uint256 start,
    uint256 stop
  ) external view returns (uint256[] memory);

  /**
   * @dev Returns an array of token IDs owned by `owner`.
   *
   * This function scans the ownership mapping and is O(totalSupply) in complexity.
   * It is meant to be called off-chain.
   *
   * See {ERC721AQueryable-tokensOfOwnerIn} for splitting the scan into
   * multiple smaller scans if the collection is large enough to cause
   * an out-of-gas error (10K pfp collections should be fine).
   */
  function tokensOfOwner(address owner) external view returns (uint256[] memory);
}

// File: src/contracts/goat/ERC721AGoat.sol



// SPDX-License-Identifier: MIT
// ERC721A Contracts v4.0.0
// Creator: Chiru Labs

pragma solidity ^0.8.4;

import "erc721a/contracts/IERC721A.sol";

/**
 * @dev ERC721 token receiver interface.
 */
interface ERC721A__IERC721Receiver {
  function onERC721Received(
    address operator,
    address from,
    uint256 tokenId,
    bytes calldata data
  ) external returns (bytes4);
}

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension. Built to optimize for lower gas during batch mints.
 *
 * Assumes serials are sequentially minted starting at _startTokenId() (defaults to 0, e.g. 0, 1, 2, 3..).
 *
 * Assumes that an owner cannot have more than 2**64 - 1 (max value of uint64) of supply.
 *
 * Assumes that the maximum token id cannot exceed 2**256 - 1 (max value of uint256).
 */
contract ERC721AGoat is IERC721A {
  // Mask of an entry in packed address data.
  uint256 private constant BITMASK_ADDRESS_DATA_ENTRY = (1 << 64) - 1;

  // The bit position of `numberMinted` in packed address data.
  uint256 private constant BITPOS_NUMBER_MINTED = 64;

  // The bit position of `numberBurned` in packed address data.
  uint256 private constant BITPOS_NUMBER_BURNED = 128;

  // The bit position of `aux` in packed address data.
  uint256 private constant BITPOS_AUX = 192;

  // Mask of all 256 bits in packed address data except the 64 bits for `aux`.
  uint256 private constant BITMASK_AUX_COMPLEMENT = (1 << 192) - 1;

  // The bit position of `startTimestamp` in packed ownership.
  uint256 private constant BITPOS_START_TIMESTAMP = 160;

  // The bit mask of the `burned` bit in packed ownership.
  uint256 private constant BITMASK_BURNED = 1 << 224;

  // The bit position of the `nextInitialized` bit in packed ownership.
  uint256 private constant BITPOS_NEXT_INITIALIZED = 225;

  // The bit mask of the `nextInitialized` bit in packed ownership.
  uint256 private constant BITMASK_NEXT_INITIALIZED = 1 << 225;

  // The tokenId of the next token to be minted.
  uint256 private _currentIndex;

  // The number of tokens burned.
  uint256 private _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 `_packedOwnershipOf` implementation for details.
  //
  // Bits Layout:
  // - [0..159]   `addr`
  // - [160..223] `startTimestamp`
  // - [224]      `burned`
  // - [225]      `nextInitialized`
  mapping(uint256 => uint256) private _packedOwnerships;

  // Mapping owner address to address data.
  //
  // Bits Layout:
  // - [0..63]    `balance`
  // - [64..127]  `numberMinted`
  // - [128..191] `numberBurned`
  // - [192..255] `aux`
  mapping(address => uint256) private _packedAddressData;

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

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

  constructor(string memory name_, string memory symbol_) {
    _name = name_;
    _symbol = symbol_;
    _currentIndex = _startTokenId();
  }

  /**
   * @dev Returns the starting token ID.
   * To change the starting token ID, please override this function.
   */
  function _startTokenId() internal view virtual returns (uint256) {
    return 0;
  }

  /**
   * @dev Returns the next token ID to be minted.
   */
  function _nextTokenId() internal view returns (uint256) {
    return _currentIndex;
  }

  /**
   * @dev Returns the total number of tokens in existence.
   * Burned tokens will reduce the count.
   * To get the total number of tokens minted, please see `_totalMinted`.
   */
  function totalSupply() public view override returns (uint256) {
    // Counter underflow is impossible as _burnCounter cannot be incremented
    // more than `_currentIndex - _startTokenId()` times.
    unchecked {
      return _currentIndex - _burnCounter - _startTokenId();
    }
  }

  /**
   * @dev Returns the total amount of tokens minted in the contract.
   */
  function _totalMinted() internal view returns (uint256) {
    // Counter underflow is impossible as _currentIndex does not decrement,
    // and it is initialized to `_startTokenId()`
    unchecked {
      return _currentIndex - _startTokenId();
    }
  }

  /**
   * @dev Returns the total number of tokens burned.
   */
  function _totalBurned() internal view returns (uint256) {
    return _burnCounter;
  }

  /**
   * @dev See {IERC165-supportsInterface}.
   */
  function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
    // The interface IDs are constants representing the first 4 bytes of the XOR of
    // all function selectors in the interface. See: https://eips.ethereum.org/EIPS/eip-165
    // e.g. `bytes4(i.functionA.selector ^ i.functionB.selector ^ ...)`
    return
      interfaceId == 0x01ffc9a7 || // ERC165 interface ID for ERC165.
      interfaceId == 0x80ac58cd || // ERC165 interface ID for ERC721.
      interfaceId == 0x5b5e139f; // ERC165 interface ID for ERC721Metadata.
  }

  /**
   * @dev See {IERC721-balanceOf}.
   */
  function balanceOf(address owner) public view override returns (uint256) {
    if (owner == address(0)) revert BalanceQueryForZeroAddress();
    return _packedAddressData[owner] & BITMASK_ADDRESS_DATA_ENTRY;
  }

  /**
   * Returns the number of tokens minted by `owner`.
   */
  function _numberMinted(address owner) internal view returns (uint256) {
    return (_packedAddressData[owner] >> BITPOS_NUMBER_MINTED) & BITMASK_ADDRESS_DATA_ENTRY;
  }

  /**
   * Returns the number of tokens burned by or on behalf of `owner`.
   */
  function _numberBurned(address owner) internal view returns (uint256) {
    return (_packedAddressData[owner] >> BITPOS_NUMBER_BURNED) & BITMASK_ADDRESS_DATA_ENTRY;
  }

  /**
   * Returns the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
   */
  function _getAux(address owner) internal view returns (uint64) {
    return uint64(_packedAddressData[owner] >> BITPOS_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 {
    uint256 packed = _packedAddressData[owner];
    uint256 auxCasted;
    assembly {
      // Cast aux without masking.
      auxCasted := aux
    }
    packed = (packed & BITMASK_AUX_COMPLEMENT) | (auxCasted << BITPOS_AUX);
    _packedAddressData[owner] = packed;
  }

  /**
   * Returns the packed ownership data of `tokenId`.
   */
  function _packedOwnershipOf(uint256 tokenId) private view returns (uint256) {
    uint256 curr = tokenId;

    unchecked {
      if (_startTokenId() <= curr)
        if (curr < _currentIndex) {
          uint256 packed = _packedOwnerships[curr];
          // If not burned.
          if (packed & BITMASK_BURNED == 0) {
            // 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.
            //
            // We can directly compare the packed value.
            // If the address is zero, packed is zero.
            while (packed == 0) {
              packed = _packedOwnerships[--curr];
            }
            return packed;
          }
        }
    }
    revert OwnerQueryForNonexistentToken();
  }

  /**
   * Returns the unpacked `TokenOwnership` struct from `packed`.
   */
  function _unpackedOwnership(uint256 packed) private pure returns (TokenOwnership memory ownership) {
    ownership.addr = address(uint160(packed));
    ownership.startTimestamp = uint64(packed >> BITPOS_START_TIMESTAMP);
    ownership.burned = packed & BITMASK_BURNED != 0;
  }

  /**
   * Returns the unpacked `TokenOwnership` struct at `index`.
   */
  function _ownershipAt(uint256 index) internal view returns (TokenOwnership memory) {
    return _unpackedOwnership(_packedOwnerships[index]);
  }

  /**
   * @dev Initializes the ownership slot minted at `index` for efficiency purposes.
   */
  function _initializeOwnershipAt(uint256 index) internal {
    if (_packedOwnerships[index] == 0) {
      _packedOwnerships[index] = _packedOwnershipOf(index);
    }
  }

  /**
   * 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) {
    return _unpackedOwnership(_packedOwnershipOf(tokenId));
  }

  /**
   * @dev See {IERC721-ownerOf}.
   */
  function ownerOf(uint256 tokenId) public view override returns (address) {
    return address(uint160(_packedOwnershipOf(tokenId)));
  }

  /**
   * @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, _toString(tokenId))) : "";
  }

  /**
   * @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 Casts the address to uint256 without masking.
   */
  function _addressToUint256(address value) private pure returns (uint256 result) {
    assembly {
      result := value
    }
  }

  /**
   * @dev Casts the boolean to uint256 without branching.
   */
  function _boolToUint256(bool value) private pure returns (uint256 result) {
    assembly {
      result := value
    }
  }

  /**
   * @dev See {IERC721-approve}.
   */
  function approve(address to, uint256 tokenId) public override {
    address owner = address(uint160(_packedOwnershipOf(tokenId)));
    if (to == owner) revert ApprovalToCurrentOwner();

    if (_msgSenderERC721A() != owner)
      if (!isApprovedForAll(owner, _msgSenderERC721A())) {
        revert ApprovalCallerNotOwnerNorApproved();
      }

    _tokenApprovals[tokenId] = to;
    emit Approval(owner, to, tokenId);
  }

  /**
   * @dev See {IERC721-getApproved}.
   */
  function getApproved(uint256 tokenId) public view override returns (address) {
    if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();

    return _tokenApprovals[tokenId];
  }

  /**
   * @dev See {IERC721-setApprovalForAll}.
   */
  function setApprovalForAll(address operator, bool approved) public virtual override {
    if (operator == _msgSenderERC721A()) revert ApproveToCaller();

    _operatorApprovals[_msgSenderERC721A()][operator] = approved;
    emit ApprovalForAll(_msgSenderERC721A(), 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, true);
  }

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

  /**
   * @dev See {IERC721-safeTransferFrom}.
   */
  function safeTransferFromWithoutCheckingNesting(
    address from,
    address to,
    uint256 tokenId
  ) internal virtual {
    _transfer(from, to, tokenId, false);
    if (to.code.length != 0)
      if (!_checkContractOnERC721Received(from, to, tokenId, "")) {
        revert TransferToNonERC721ReceiverImplementer();
      }
  }

  /**
   * @dev See {IERC721-safeTransferFrom}.
   */
  function safeTransferFrom(
    address from,
    address to,
    uint256 tokenId,
    bytes memory _data
  ) public virtual override {
    _transfer(from, to, tokenId, true);
    if (to.code.length != 0)
      if (!_checkContractOnERC721Received(from, to, tokenId, _data)) {
        revert TransferToNonERC721ReceiverImplementer();
      }
  }

  /**
   * @dev Returns whether `tokenId` exists.
   *
   * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
   *
   * Tokens start existing when they are minted (`_mint`),
   */
  function _exists(uint256 tokenId) internal view returns (bool) {
    return
      _startTokenId() <= tokenId &&
      tokenId < _currentIndex && // If within bounds,
      _packedOwnerships[tokenId] & BITMASK_BURNED == 0; // and not burned.
  }

  /**
   * @dev Equivalent to `_safeMint(to, quantity, '')`.
   */
  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 {
    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 {
      // Updates:
      // - `balance += quantity`.
      // - `numberMinted += quantity`.
      //
      // We can directly add to the balance and number minted.
      _packedAddressData[to] += quantity * ((1 << BITPOS_NUMBER_MINTED) | 1);

      // Updates:
      // - `address` to the owner.
      // - `startTimestamp` to the timestamp of minting.
      // - `burned` to `false`.
      // - `nextInitialized` to `quantity == 1`.
      _packedOwnerships[startTokenId] =
        _addressToUint256(to) |
        (block.timestamp << BITPOS_START_TIMESTAMP) |
        (_boolToUint256(quantity == 1) << BITPOS_NEXT_INITIALIZED);

      uint256 updatedIndex = startTokenId;
      uint256 end = updatedIndex + quantity;

      if (to.code.length != 0) {
        do {
          emit Transfer(address(0), to, updatedIndex);
          if (!_checkContractOnERC721Received(address(0), to, updatedIndex++, _data)) {
            revert TransferToNonERC721ReceiverImplementer();
          }
        } while (updatedIndex < end);
        // Reentrancy protection
        if (_currentIndex != startTokenId) revert();
      } else {
        do {
          emit Transfer(address(0), to, updatedIndex++);
        } while (updatedIndex < end);
      }
      _currentIndex = updatedIndex;
    }
    _afterTokenTransfers(address(0), to, startTokenId, quantity);
  }

  /**
   * @dev 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) 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 {
      // Updates:
      // - `balance += quantity`.
      // - `numberMinted += quantity`.
      //
      // We can directly add to the balance and number minted.
      _packedAddressData[to] += quantity * ((1 << BITPOS_NUMBER_MINTED) | 1);

      // Updates:
      // - `address` to the owner.
      // - `startTimestamp` to the timestamp of minting.
      // - `burned` to `false`.
      // - `nextInitialized` to `quantity == 1`.
      _packedOwnerships[startTokenId] =
        _addressToUint256(to) |
        (block.timestamp << BITPOS_START_TIMESTAMP) |
        (_boolToUint256(quantity == 1) << BITPOS_NEXT_INITIALIZED);

      uint256 updatedIndex = startTokenId;
      uint256 end = updatedIndex + quantity;

      do {
        emit Transfer(address(0), to, updatedIndex++);
      } while (updatedIndex < end);

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

  /**
   * @dev Transfers `tokenId` from `from` to `to`.
   *
   * Requirements:
   *
   * - `to` cannot be the zero address.
   * - `tokenId` token must be owned by `from`.
   *
   * Emits a {Transfer} event.
   */
  function _transfer(
    address from,
    address to,
    uint256 tokenId,
    bool checkNesting
  ) private {
    uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);

    if (address(uint160(prevOwnershipPacked)) != from) revert TransferFromIncorrectOwner();

    bool isApprovedOrOwner = (_msgSenderERC721A() == from ||
      isApprovedForAll(from, _msgSenderERC721A()) ||
      getApproved(tokenId) == _msgSenderERC721A());

    if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
    if (to == address(0)) revert TransferToZeroAddress();

    if (checkNesting) {
      _beforeTokenTransfers(from, to, tokenId, 1);
    }

    // Clear approvals from the previous owner.
    delete _tokenApprovals[tokenId];

    // 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 {
      // We can directly increment and decrement the balances.
      --_packedAddressData[from]; // Updates: `balance -= 1`.
      ++_packedAddressData[to]; // Updates: `balance += 1`.

      // Updates:
      // - `address` to the next owner.
      // - `startTimestamp` to the timestamp of transfering.
      // - `burned` to `false`.
      // - `nextInitialized` to `true`.
      _packedOwnerships[tokenId] =
        _addressToUint256(to) |
        (block.timestamp << BITPOS_START_TIMESTAMP) |
        BITMASK_NEXT_INITIALIZED;

      // If the next slot may not have been initialized (i.e. `nextInitialized == false`) .
      if (prevOwnershipPacked & BITMASK_NEXT_INITIALIZED == 0) {
        uint256 nextTokenId = tokenId + 1;
        // If the next slot's address is zero and not burned (i.e. packed value is zero).
        if (_packedOwnerships[nextTokenId] == 0) {
          // If the next slot is within bounds.
          if (nextTokenId != _currentIndex) {
            // Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.
            _packedOwnerships[nextTokenId] = prevOwnershipPacked;
          }
        }
      }
    }

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

  /**
   * @dev Equivalent to `_burn(tokenId, false)`.
   */
  function _burn(uint256 tokenId) internal virtual {
    _burn(tokenId, false);
  }

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

    address from = address(uint160(prevOwnershipPacked));

    if (approvalCheck) {
      bool isApprovedOrOwner = (_msgSenderERC721A() == from ||
        isApprovedForAll(from, _msgSenderERC721A()) ||
        getApproved(tokenId) == _msgSenderERC721A());

      if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
    }

    _beforeTokenTransfers(from, address(0), tokenId, 1);

    // Clear approvals from the previous owner.
    delete _tokenApprovals[tokenId];

    // 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 {
      // Updates:
      // - `balance -= 1`.
      // - `numberBurned += 1`.
      //
      // We can directly decrement the balance, and increment the number burned.
      // This is equivalent to `packed -= 1; packed += 1 << BITPOS_NUMBER_BURNED;`.
      _packedAddressData[from] += (1 << BITPOS_NUMBER_BURNED) - 1;

      // Updates:
      // - `address` to the last owner.
      // - `startTimestamp` to the timestamp of burning.
      // - `burned` to `true`.
      // - `nextInitialized` to `true`.
      _packedOwnerships[tokenId] =
        _addressToUint256(from) |
        (block.timestamp << BITPOS_START_TIMESTAMP) |
        BITMASK_BURNED |
        BITMASK_NEXT_INITIALIZED;

      // If the next slot may not have been initialized (i.e. `nextInitialized == false`) .
      if (prevOwnershipPacked & BITMASK_NEXT_INITIALIZED == 0) {
        uint256 nextTokenId = tokenId + 1;
        // If the next slot's address is zero and not burned (i.e. packed value is zero).
        if (_packedOwnerships[nextTokenId] == 0) {
          // If the next slot is within bounds.
          if (nextTokenId != _currentIndex) {
            // Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.
            _packedOwnerships[nextTokenId] = prevOwnershipPacked;
          }
        }
      }
    }

    emit Transfer(from, address(0), tokenId);
    _afterTokenTransfers(from, address(0), tokenId, 1);

    // Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.
    unchecked {
      _burnCounter++;
    }
  }

  /**
   * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target contract.
   *
   * @param from address representing the previous owner of the given token ID
   * @param to target address that will receive the tokens
   * @param tokenId uint256 ID of the token to be transferred
   * @param _data bytes optional data to send along with the call
   * @return bool whether the call correctly returned the expected magic value
   */
  function _checkContractOnERC721Received(
    address from,
    address to,
    uint256 tokenId,
    bytes memory _data
  ) private returns (bool) {
    try ERC721A__IERC721Receiver(to).onERC721Received(_msgSenderERC721A(), from, tokenId, _data) returns (
      bytes4 retval
    ) {
      return retval == ERC721A__IERC721Receiver(to).onERC721Received.selector;
    } catch (bytes memory reason) {
      if (reason.length == 0) {
        revert TransferToNonERC721ReceiverImplementer();
      } else {
        assembly {
          revert(add(32, reason), mload(reason))
        }
      }
    }
  }

  /**
   * @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
   * And also called before burning one token.
   *
   * startTokenId - the first token id to be transferred
   * quantity - the amount to be transferred
   *
   * Calling conditions:
   *
   * - When `from` and `to` are both non-zero, `from`'s `tokenId` will be
   * transferred to `to`.
   * - When `from` is zero, `tokenId` will be minted for `to`.
   * - When `to` is zero, `tokenId` will be burned by `from`.
   * - `from` and `to` are never both zero.
   */
  function _beforeTokenTransfers(
    address from,
    address to,
    uint256 startTokenId,
    uint256 quantity
  ) internal virtual {}

  /**
   * @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes
   * minting.
   * And also called after one token has been burned.
   *
   * startTokenId - the first token id to be transferred
   * quantity - the amount to be transferred
   *
   * Calling conditions:
   *
   * - When `from` and `to` are both non-zero, `from`'s `tokenId` has been
   * transferred to `to`.
   * - When `from` is zero, `tokenId` has been minted for `to`.
   * - When `to` is zero, `tokenId` has been burned by `from`.
   * - `from` and `to` are never both zero.
   */
  function _afterTokenTransfers(
    address from,
    address to,
    uint256 startTokenId,
    uint256 quantity
  ) internal virtual {}

  /**
   * @dev Returns the message sender (defaults to `msg.sender`).
   *
   * If you are writing GSN compatible contracts, you need to override this function.
   */
  function _msgSenderERC721A() internal view virtual returns (address) {
    return msg.sender;
  }

  /**
   * @dev Converts a `uint256` to its ASCII `string` decimal representation.
   */
  function _toString(uint256 value) internal pure returns (string memory ptr) {
    assembly {
      // The maximum value of a uint256 contains 78 digits (1 byte per digit),
      // but we allocate 128 bytes to keep the free memory pointer 32-byte word aliged.
      // We will need 1 32-byte word to store the length,
      // and 3 32-byte words to store a maximum of 78 digits. Total: 32 + 3 * 32 = 128.
      ptr := add(mload(0x40), 128)
      // Update the free memory pointer to allocate.
      mstore(0x40, ptr)

      // Cache the end of the memory to calculate the length later.
      let end := ptr

      // We write the string from the rightmost digit to the leftmost digit.
      // The following is essentially a do-while loop that also handles the zero case.
      // Costs a bit more than early returning for the zero case,
      // but cheaper in terms of deployment and overall runtime costs.
      for {
        // Initialize and perform the first pass without check.
        let temp := value
        // Move the pointer 1 byte leftwards to point to an empty character slot.
        ptr := sub(ptr, 1)
        // Write the character to the pointer. 48 is the ASCII index of '0'.
        mstore8(ptr, add(48, mod(temp, 10)))
        temp := div(temp, 10)
      } temp {
        // Keep dividing `temp` until zero.
        temp := div(temp, 10)
      } {
        // Body of the for loop.
        ptr := sub(ptr, 1)
        mstore8(ptr, add(48, mod(temp, 10)))
      }

      let length := sub(end, ptr)
      // Move the pointer 32 bytes leftwards to make room for the length.
      ptr := sub(ptr, 32)
      // Store the length.
      mstore(ptr, length)
    }
  }
}

// File: erc721a/contracts/IERC721A.sol



// SPDX-License-Identifier: MIT
// ERC721A Contracts v4.0.0
// Creator: Chiru Labs

pragma solidity ^0.8.4;

/**
 * @dev Interface of an ERC721A compliant contract.
 */
interface IERC721A {
    /**
     * The caller must own the token or be an approved operator.
     */
    error ApprovalCallerNotOwnerNorApproved();

    /**
     * The token does not exist.
     */
    error ApprovalQueryForNonexistentToken();

    /**
     * The caller cannot approve to their own address.
     */
    error ApproveToCaller();

    /**
     * The caller cannot approve to the current owner.
     */
    error ApprovalToCurrentOwner();

    /**
     * Cannot query the balance for the zero address.
     */
    error BalanceQueryForZeroAddress();

    /**
     * Cannot mint to the zero address.
     */
    error MintToZeroAddress();

    /**
     * The quantity of tokens minted must be more than zero.
     */
    error MintZeroQuantity();

    /**
     * The token does not exist.
     */
    error OwnerQueryForNonexistentToken();

    /**
     * The caller must own the token or be an approved operator.
     */
    error TransferCallerNotOwnerNorApproved();

    /**
     * The token must be owned by `from`.
     */
    error TransferFromIncorrectOwner();

    /**
     * Cannot safely transfer to a contract that does not implement the ERC721Receiver interface.
     */
    error TransferToNonERC721ReceiverImplementer();

    /**
     * Cannot transfer to the zero address.
     */
    error TransferToZeroAddress();

    /**
     * The token does not exist.
     */
    error URIQueryForNonexistentToken();

    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;
    }

    /**
     * @dev Returns the total amount of tokens stored by the contract.
     *
     * Burned tokens are calculated here, use `_totalMinted()` if you want to count just minted tokens.
     */
    function totalSupply() external view returns (uint256);

    // ==============================
    //            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);

    // ==============================
    //            IERC721
    // ==============================

    /**
     * @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`.
     *
     * 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;

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

    /**
     * @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);

    // ==============================
    //        IERC721Metadata
    // ==============================

    /**
     * @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);
}