// File: contracts/FrankenPunks.sol



// SPDX-License-Identifier: MIT

/**
 _______  _______  _______  _        _        _______  _          _______           _        _        _______
(  ____ \(  ____ )(  ___  )( (    /|| \    /\(  ____ \( (    /|  (  ____ )|\     /|( (    /|| \    /\(  ____ \
| (    \/| (    )|| (   ) ||  \  ( ||  \  / /| (    \/|  \  ( |  | (    )|| )   ( ||  \  ( ||  \  / /| (    \/
| (__    | (____)|| (___) ||   \ | ||  (_/ / | (__    |   \ | |  | (____)|| |   | ||   \ | ||  (_/ / | (_____
|  __)   |     __)|  ___  || (\ \) ||   _ (  |  __)   | (\ \) |  |  _____)| |   | || (\ \) ||   _ (  (_____  )
| (      | (\ (   | (   ) || | \   ||  ( \ \ | (      | | \   |  | (      | |   | || | \   ||  ( \ \       ) |
| )      | ) \ \__| )   ( || )  \  ||  /  \ \| (____/\| )  \  |  | )      | (___) || )  \  ||  /  \ \/\____) |
|/       |/   \__/|/     \||/    )_)|_/    \/(_______/|/    )_)  |/       (_______)|/    )_)|_/    \/\_______)

*/

pragma solidity ^0.8.9;

import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
import { ERC721 } from "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import { Address } from "@openzeppelin/contracts/utils/Address.sol";
import { Strings } from "@openzeppelin/contracts/utils/Strings.sol";
import { MerkleProof } from "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";

/**
 * @title FrankenPunks contract.
 * @author The FrankenPunks team.
 *
 * @notice Implements a fair and random NFT distribution, based on the Hashmasks/BAYC model.
 *
 *  Additional features include:
 *   - Merkle-tree whitelist with customizable number of mints per address.
 *   - Dutch-auction pricing.
 *   - On-chain support for a pre-reveal placeholder image.
 *   - Contract-level metadata.
 *   - Finalization of metadata to prevent further changes.
 */
contract FrankenPunks is ERC721, Ownable {
    using Strings for uint256;

    event SetPresaleMerkleRoot(bytes32 root);
    event SetProvenanceHash(string provenanceHash);
    event SetAuctionStartAndEnd(uint256 auctionStart, uint256 auctionEnd);
    event SetPresaleIsActive(bool presaleIsActive);
    event SetSaleIsActive(bool saleIsActive);
    event SetIsRevealed(bool isRevealed);
    event Finalized();
    event SetRoyaltyInfo(address royaltyRecipient, uint256 royaltyAmountNumerator);
    event SetStartingIndexBlockNumber(uint256 blockNumber, bool usedForce);
    event SetStartingIndex(uint256 startingIndex, uint256 blockNumber);
    event SetBaseURI(string baseURI);
    event SetPlaceholderURI(string placeholderURI);
    event SetContractURI(string contractURI);
    event Withdrew(uint256 balance);

    uint256 public constant MAX_SUPPLY = 10000;
    uint256 public constant MAX_MINT_PER_TX = 5;
    uint256 public constant RESERVED_SUPPLY = 300;
    uint256 public constant PRESALE_PRICE = 0.088 ether;
    uint256 public constant AUCTION_PRICE_START = 0.5 ether;
    uint256 public constant AUCTION_PRICE_END = 0.088 ether;
    string public constant TOKEN_URI_EXTENSION = ".json";
    uint256 public constant ROYALTY_AMOUNT_DENOMINATOR = 1e18;
    bytes4 private constant INTERFACE_ID_ERC2981 = 0x2a55205a;

    /// @notice The root of the Merkle tree with addresses allowed to mint in the presale.
    bytes32 public _presaleMerkleRoot;

    /// @notice Hash which commits to the content, metadata, and original sequence of the NFTs.
    string public _provenanceHash;

    /// @notice The start time, used to set the price. Does not affect whether minting is allowed.
    uint256 public _auctionStart;

    /// @notice The end time, used to set the price. Does not affect whether minting is allowed.
    uint256 public _auctionEnd;

    /// @notice Controls whether minting is allowed via the presale mint function.
    bool public _presaleIsActive = false;

    /// @notice Controls whether minting is allowed via the regular mint function.
    bool public _saleIsActive = false;

    /// @notice Whether the placeholder URI should be returned for all tokens.
    bool public _isRevealed = false;

    /// @notice Whether further changes to the provenance hash and token URI have been disabled.
    bool public _isFinalized = false;

    /// @notice The recipient of ERC-2981 royalties.
    address public _royaltyRecipient;

    /// @notice The royalty rate for ERC-2981 royalties, as a fraction of ROYALTY_AMOUNT_DENOMINATOR.
    uint256 public _royaltyAmountNumerator;

    /// @notice The number of presale mints completed by address.
    mapping(address => uint256) public _numPresaleMints;

    /// @notice Whether the address used the voucher amount specified in the Merkle tree.
    ///  Note that we assume each address is only included once in the Merkle tree.
    mapping(address => bool) public _usedVoucher;

    /// @notice The block number to be used to derive the starting index.
    uint256 public _startingIndexBlockNumber;

    /// @notice The starting index, chosen pseudorandomly to ensure a fair and random distribution.
    uint256 public _startingIndex;

    /// @notice Whether the starting index was set.
    bool public _startingIndexWasSet;

    string internal _baseTokenURI;
    string internal _placeholderURI;
    string internal _contractURI;

    uint256 internal _totalSupply;

    modifier notFinalized() {
        require(
            !_isFinalized,
            "Metadata is finalized"
        );
        _;
    }

    constructor(
        string memory placeholderURI
    ) ERC721("FrankenPunks", "FP") {
        _placeholderURI = placeholderURI;
    }

    function setPresaleMerkleRoot(bytes32 root) external onlyOwner {
        _presaleMerkleRoot = root;
        emit SetPresaleMerkleRoot(root);
    }

    function setProvenanceHash(string calldata provenanceHash) external onlyOwner notFinalized {
        _provenanceHash = provenanceHash;
        emit SetProvenanceHash(provenanceHash);
    }

    function setAuctionStartAndEnd(uint256 auctionStart, uint256 auctionEnd) external onlyOwner {
        require(
            auctionStart <= auctionEnd,
            "Start must precede end"
        );
        _auctionStart = auctionStart;
        _auctionEnd = auctionEnd;
        emit SetAuctionStartAndEnd(auctionStart, auctionEnd);
    }

    function setPresaleIsActive(bool presaleIsActive) external onlyOwner {
        _presaleIsActive = presaleIsActive;
        emit SetPresaleIsActive(presaleIsActive);
    }

    function setSaleIsActive(bool saleIsActive) external onlyOwner {
        require(
            !saleIsActive || (_auctionStart != 0 && _auctionEnd != 0),
            "Auction params must be set"
        );
        _saleIsActive = saleIsActive;
        emit SetSaleIsActive(saleIsActive);
    }

    function setIsRevealed(bool isRevealed) external onlyOwner notFinalized {
        _isRevealed = isRevealed;
        emit SetIsRevealed(isRevealed);
    }

    function finalize() external onlyOwner notFinalized {
        require(
            _isRevealed,
            "Must be revealed to finalize"
        );
        _isFinalized = true;
        emit Finalized();
    }

    function setRoyaltyInfo(address royaltyRecipient, uint256 royaltyAmountNumerator) external onlyOwner {
        _royaltyRecipient = royaltyRecipient;
        _royaltyAmountNumerator = royaltyAmountNumerator;
        emit SetRoyaltyInfo(royaltyRecipient, royaltyAmountNumerator);
    }

    function setBaseURI(string calldata baseURI) external onlyOwner notFinalized {
        _baseTokenURI = baseURI;
        emit SetBaseURI(baseURI);
    }

    function setPlaceholderURI(string calldata placeholderURI) external onlyOwner {
        _placeholderURI = placeholderURI;
        emit SetPlaceholderURI(placeholderURI);
    }

    function setContractURI(string calldata newContractURI) external onlyOwner {
        _contractURI = newContractURI;
        emit SetContractURI(newContractURI);
    }

    function withdraw() external onlyOwner {
        uint256 balance = address(this).balance;
        payable(msg.sender).transfer(balance);
        emit Withdrew(balance);
    }

    function mintReservedTokens(address recipient, uint256 numToMint) external onlyOwner {
        uint256 startingSupply = _totalSupply;

        require(
            startingSupply + numToMint <= RESERVED_SUPPLY,
            "Mint would exceed reserved supply"
        );

        // Update the total supply.
        _totalSupply = startingSupply + numToMint;

        // Note: First token has ID #0.
        for (uint256 i = 0; i < numToMint; i++) {
            // Use _mint() instead of _safeMint() since we won't mint to contracts.
            _mint(recipient, startingSupply + i);
        }
    }

    function fallbackSetStartingIndexBlockNumber() external onlyOwner {
        require(
            _startingIndexBlockNumber == 0,
            "Block number was set"
        );
        _setStartingIndexBlockNumber(true);
    }

    /**
     * @notice Called by users to mint from the presale.
     */
    function mintPresale(
        uint256 numToMint,
        uint256 maxMints,
        uint256 voucherAmount,
        bytes32[] calldata merkleProof
    ) external payable {
        require(
            _presaleIsActive,
            "Presale not active"
        );

        // The Merkle tree node contains: (address account, uint256 maxMints, uint256 voucherAmount)
        bytes32 leaf = keccak256(abi.encodePacked(msg.sender, maxMints, voucherAmount));

        // Verify the mint params are part of the Merkle tree, given the Merkle proof.
        require(
            MerkleProof.verify(merkleProof, _presaleMerkleRoot, leaf),
            "Invalid Merkle proof"
        );

        // Require that the minter does not exceed their max allocation given by the Merkle tree.
        uint256 newNumPresaleMints = _numPresaleMints[msg.sender] + numToMint;
        require(
            newNumPresaleMints <= maxMints,
            "Presale mints exceeded"
        );

        // Use the voucher amount if it wasn't previously used.
        uint256 remainingVoucherAmount = 0;
        if (voucherAmount != 0 && !_usedVoucher[msg.sender]) {
            remainingVoucherAmount = voucherAmount;
            _usedVoucher[msg.sender] = true;
        }

        // Update storage (do this before minting as mint recipients may have callbacks).
        _numPresaleMints[msg.sender] = newNumPresaleMints;

        // Mint tokens, checking for sufficient payment and supply.
        _mintInner(numToMint, true, remainingVoucherAmount);
    }

    /**
     * @notice Called by users to mint from the main sale.
     */
    function mint(uint256 numToMint) external payable {
        require(
            _saleIsActive,
            "Sale not active"
        );
        require(
            numToMint <= MAX_MINT_PER_TX,
            "numToMint too large"
        );

        // Mint tokens, checking for sufficient payment and supply.
        _mintInner(numToMint, false, 0);
    }

    /**
     * @notice Fix the starting index using the previously determined block number.
     */
    function setStartingIndex() external {
        require(
            !_startingIndexWasSet,
            "Starting index was set"
        );

        uint256 targetBlock = _startingIndexBlockNumber;

        require(
            targetBlock != 0,
            "Block number not set"
        );

        // If the hash for the desired block is unavailable, fall back to the most recent block.
        if (block.number - targetBlock > 256) {
            targetBlock = block.number - 1;
        }

        uint256 startingIndex = uint256(blockhash(targetBlock)) % MAX_SUPPLY;
        _startingIndex = startingIndex;
        _startingIndexWasSet = true;
        emit SetStartingIndex(startingIndex, targetBlock);
    }

    /**
     * @notice Query tokens owned by an address, in a given range.
     *
     * Adapted from Nanopass: https://etherscan.io/address/0xf54cc94f1f2f5de012b6aa51f1e7ebdc43ef5afc#code
     */
    function tokensOfOwner(address owner, uint256 startId, uint256 endId) external view returns(uint256[] memory) {
        uint256 tokenCount = balanceOf(owner);
        uint256[] memory ownerTokens = new uint256[](tokenCount);
        uint256 ownerIndex = 0;
        for (uint256 tokenId = startId; tokenId < endId; tokenId++) {
            if (ownerIndex == tokenCount) break;

            if (ownerOf(tokenId) == owner) {
                ownerTokens[ownerIndex] = tokenId;
                ownerIndex++;
            }
        }
        return ownerTokens;
    }

    /**
     * @notice Query all tokens owned by an address.
     *
     * Adapted from Nanopass: https://etherscan.io/address/0xf54cc94f1f2f5de012b6aa51f1e7ebdc43ef5afc#code
     */
    function walletOfOwner(address owner) external view returns(uint256[] memory) {
        return this.tokensOfOwner(owner, 0, _totalSupply);
    }

    /**
     * @notice Implements ERC-2981 royalty info interface.
     */
    function royaltyInfo(uint256 /* tokenId */, uint256 salePrice) external view returns (address, uint256) {
        return (_royaltyRecipient, salePrice * _royaltyAmountNumerator / ROYALTY_AMOUNT_DENOMINATOR);
    }

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

    function tokenURI(uint256 tokenId) public view override returns (string memory) {
        require(
            _exists(tokenId),
            "ERC721Metadata: URI query for nonexistent token"
        );

        if (!_isRevealed) {
            return _placeholderURI;
        }

        string memory baseURI = _baseTokenURI;
        return bytes(baseURI).length > 0
            ? string(abi.encodePacked(baseURI, tokenId.toString(), TOKEN_URI_EXTENSION))
            : "";
    }
    
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return (
            interfaceId == INTERFACE_ID_ERC2981 ||
            super.supportsInterface(interfaceId)
        );
    }

    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    function getCurrentAuctionPrice() public view returns (uint256) {
        uint256 auctionStart = _auctionStart;
        uint256 auctionEnd = _auctionEnd;
        uint256 timestamp = block.timestamp;
        if (auctionStart == 0 || auctionEnd == 0 || auctionStart >= timestamp) {
            return AUCTION_PRICE_START;
        }
        if (auctionEnd <= timestamp) {
            return AUCTION_PRICE_END;
        }

        // If timestamp is between start and end, interpolate to find the price.
        uint256 progress = (timestamp - auctionStart) * 1e18 / (auctionEnd - auctionStart);
        return AUCTION_PRICE_START - ((AUCTION_PRICE_START - AUCTION_PRICE_END) * progress / 1e18);
    }

    function getCost(uint256 numToMint, bool isPresale) public view returns (uint256) {
        if (isPresale) {
            return numToMint * PRESALE_PRICE;
        }
        return numToMint * getCurrentAuctionPrice();
    }

    /**
     * @dev Mints `numToMint` tokens to msg.sender.
     *
     *  Reverts if the max supply would be exceeded.
     *  Reverts if the payment amount (`msg.value`) is insufficient.
     */
    function _mintInner(uint256 numToMint, bool isPresale, uint256 voucherAmount) internal {
        uint256 startingSupply = _totalSupply;

        require(
            startingSupply + numToMint <= MAX_SUPPLY,
            "Mint would exceed max supply"
        );
        require(
            getCost(numToMint, isPresale) <= msg.value + voucherAmount,
            "Insufficient payment"
        );
        require(
            !Address.isContract(msg.sender),
            "Cannot mint from a contract"
        );

        // Update the total supply.
        _totalSupply = startingSupply + numToMint;

        // Note: First token has ID #0.
        for (uint256 i = 0; i < numToMint; i++) {
            // Use _mint() instead of _safeMint() since we won't mint to contracts.
            _mint(msg.sender, startingSupply + i);
        }

        // Finalize the starting index block number when the last token is purchased.
        if (startingSupply + numToMint == MAX_SUPPLY) {
            // NOTE: Do not set the starting index block automatically if the provenance has is not published!
            // If the provenance hash is not ready by the end of the sale, then the block number can be set
            // with fallbackSetStartingIndexBlockNumber(), which is also fine.
            if (bytes(_provenanceHash).length != 0) {
                _setStartingIndexBlockNumber(false);
            }
        }
    }

    function _setStartingIndexBlockNumber(bool usedForce) internal {
        // Add one to make it even harder to manipulate.
        // Ref: https://github.com/the-torn/floot#floot-seed-generation
        uint256 blockNumber = block.number + 1;
        _startingIndexBlockNumber = blockNumber;
        emit SetStartingIndexBlockNumber(blockNumber, usedForce);
    }
}

// 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/token/ERC721/ERC721.sol



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

pragma solidity ^0.8.0;

import "./IERC721.sol";
import "./IERC721Receiver.sol";
import "./extensions/IERC721Metadata.sol";
import "../../utils/Address.sol";
import "../../utils/Context.sol";
import "../../utils/Strings.sol";
import "../../utils/introspection/ERC165.sol";

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension, but not including the Enumerable extension, which is available separately as
 * {ERC721Enumerable}.
 */
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Mapping from token ID to owner address
    mapping(uint256 => address) private _owners;

    // Mapping owner address to token count
    mapping(address => uint256) private _balances;

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

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

    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @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 virtual override returns (uint256) {
        require(owner != address(0), "ERC721: balance query for the zero address");
        return _balances[owner];
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _owners[tokenId];
        require(owner != address(0), "ERC721: owner query for nonexistent token");
        return owner;
    }

    /**
     * @dev See {IERC721Metadata-name}.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev See {IERC721Metadata-symbol}.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");

        string memory baseURI = _baseURI();
        return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
    }

    /**
     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
     * by default, can be overriden in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return "";
    }

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721.ownerOf(tokenId);
        require(to != owner, "ERC721: approval to current owner");

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            "ERC721: approve caller is not owner nor approved for all"
        );

        _approve(to, tokenId);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), "ERC721: approved query for nonexistent token");

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        _setApprovalForAll(_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 {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");

        _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 {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        _safeTransfer(from, to, tokenId, _data);
    }

    /**
     * @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.
     *
     * `_data` is additional data, it has no specified format and it is sent in call to `to`.
     *
     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
     * implement alternative mechanisms to perform token transfer, such as signature-based.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeTransfer(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) internal virtual {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted (`_mint`),
     * and stop existing when they are burned (`_burn`).
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _owners[tokenId] != address(0);
    }

    /**
     * @dev Returns whether `spender` is allowed to manage `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        require(_exists(tokenId), "ERC721: operator query for nonexistent token");
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
    }

    /**
     * @dev Safely mints `tokenId` and transfers it to `to`.
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(address to, uint256 tokenId) internal virtual {
        _safeMint(to, tokenId, "");
    }

    /**
     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
     */
    function _safeMint(
        address to,
        uint256 tokenId,
        bytes memory _data
    ) internal virtual {
        _mint(to, tokenId);
        require(
            _checkOnERC721Received(address(0), to, tokenId, _data),
            "ERC721: transfer to non ERC721Receiver implementer"
        );
    }

    /**
     * @dev Mints `tokenId` and transfers it to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - `to` cannot be the zero address.
     *
     * Emits a {Transfer} event.
     */
    function _mint(address to, uint256 tokenId) internal virtual {
        require(to != address(0), "ERC721: mint to the zero address");
        require(!_exists(tokenId), "ERC721: token already minted");

        _beforeTokenTransfer(address(0), to, tokenId);

        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(address(0), to, tokenId);
    }

    /**
     * @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 {
        address owner = ERC721.ownerOf(tokenId);

        _beforeTokenTransfer(owner, address(0), tokenId);

        // Clear approvals
        _approve(address(0), tokenId);

        _balances[owner] -= 1;
        delete _owners[tokenId];

        emit Transfer(owner, address(0), tokenId);
    }

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
     *
     * 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
    ) internal virtual {
        require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own");
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId);

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

        _balances[from] -= 1;
        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(from, to, tokenId);
    }

    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits a {Approval} event.
     */
    function _approve(address to, uint256 tokenId) internal virtual {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
    }

    /**
     * @dev Approve `operator` to operate on all of `owner` tokens
     *
     * Emits a {ApprovalForAll} event.
     */
    function _setApprovalForAll(
        address owner,
        address operator,
        bool approved
    ) internal virtual {
        require(owner != operator, "ERC721: approve to caller");
        _operatorApprovals[owner][operator] = approved;
        emit ApprovalForAll(owner, operator, approved);
    }

    /**
     * @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.onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("ERC721: transfer to non ERC721Receiver implementer");
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * 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, ``from``'s `tokenId` will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}
}

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



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

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

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



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

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}

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



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

pragma solidity ^0.8.0;

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

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

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

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

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {
    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;

import "./IERC165.sol";

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

// File: @openzeppelin/contracts/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);
}