// File: /contracts/contracts/endangered-mints/mints/EndangeredMintGoldenRhino.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.8;

import "./EndangeredMint.sol";

/**
 * @dev EndangeredMint implementation for the first distribution -- Rhino.
 */
contract EndangeredMintGoldenRhino is EndangeredMint {

    constructor(
        uint256 startTime_
    ) EndangeredMint("Endangered Mints Golden Rhino",
        "EM",
        "ipfs://QmNa7xWWf93trTb4ZkygpzB8Zspxscr1c3deXKdxWJLJfs/",
        startTime_,
        0x817A7c8F73a4AC6C419d2793e416a351B47BE1D2
    ) {}

}
// File: /contracts/utils/Strings.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.8;

/**
 * @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: /contracts/interfaces/ERC/internal/IERC721Receiver.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.8;

/**
 * @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: /contracts/interfaces/ERC/internal/IERC721Metadata.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.8;

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: /contracts/interfaces/ERC/internal/IERC721Enumerable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.8;

import "./IERC721.sol";

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

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

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}
// File: /contracts/interfaces/ERC/internal/IERC721.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.8;

import "./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: /contracts/interfaces/ERC/internal/IERC165.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.8;

/**
 * @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);
}
// File: /contracts/interfaces/ERC/IERC721MetadataEnumerable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.8;

import "./internal/IERC721Metadata.sol";
import "./internal/IERC721Enumerable.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, with the optional Metadata and Enumerable extensions
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721MetadataEnumerable is IERC721Metadata, IERC721Enumerable {
    
}
// File: /contracts/contracts/endangered-mints/mints/EndangeredMint.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.8;

import "../../ERC/ERC721MetadataEnumerable.sol";
import "../../../utils/Strings.sol";

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension and the Enumerable extension, designed for the Endangered Mints NFT project.
 */
contract EndangeredMint is ERC721MetadataEnumerable {
    using Strings for uint256;

    address private _conservation;

    uint256 private _conservationOpen;
    uint256 private _conservationClose;
    uint256 private _conservationLock;
    uint256 private _conserved;

    constructor(
        string memory name_,
        string memory symbol_,
        string memory baseURI_,
        uint256 startTime_,
        address conservation_
    ) ERC721MetadataEnumerable(name_, symbol_, baseURI_) {
        _conservationOpen = startTime_;
        _conservationClose = _conservationOpen + 1 weeks;
        // First release has a 3 week window for reward distribution and metadata updates
        _conservationLock = _conservationClose + 3 weeks;
        _conservation = conservation_;
        _conserved = 0;

        /* Mint Founder's Edition Mints */
        for (uint8 i = 0; i < 5; i++) {
            _safeMintInternal(_conservation, "");
        }

        /* Mint reserved community Mints */
        for (uint8 i = 0; i < 5; i++) {
            _safeMintInternal(_conservation, "");
        }
    }

    modifier conservationOwner() {
        require(_conservation == msg.sender, "Only the conservation owner can perform maintenance");
        _;
    }

    function safeMint(address to) public payable virtual {
        safeMint(to, "");
    }
    
    function safeMint(address to, bytes memory _data) public payable virtual {
        _requireMintable();
        _purchase();
        _safeMintInternal(to, _data);
    }

    function mint(address to) public payable virtual {
        _requireMintable();
        _purchase();
        uint256 tokenId = ERC721MetadataEnumerable.totalSupply() + 1;
        ERC721MetadataEnumerable._mint(to, tokenId);
        _conserved += 1;
    }

    function conservationOpen() external view virtual returns(uint256) {
        return _conservationOpen;
    }

    function conservationClose() external view virtual returns(uint256) {
        return _conservationClose;
    }

    function conservationLock() external view virtual returns(uint256) {
        return _conservationLock;
    }

    function _safeMintInternal(address to, bytes memory _data) internal virtual {
        uint256 tokenId = ERC721MetadataEnumerable.totalSupply() + 1;
        ERC721MetadataEnumerable._safeMint(to, tokenId, _data);
        _conserved += 1;
    }

    function _requireMintable() internal view virtual {
        require(_conserved < 1000, "All endangered mints have been conserved");
        require(block.timestamp >= _conservationOpen, "Minting has not yet started");
        require(block.timestamp < _conservationClose, "Minting is no longer possible, sale has ended");
    }

    function _purchase() internal virtual {
        require(msg.value == 0.25 ether, "Payment amount must equal 0.25 Ether");
        (bool paid, ) = _conservation.call{value: msg.value}("");
        require(paid, "Unable to send payment, recipient may have reverted");
    }

    function conservationists() public view virtual returns (address[] memory) {
        address[] memory addrs = new address[](_conserved);
        for (uint256 i = 1; i <= _conserved; i++) {
            addrs[i - 1] = ownerOf(i);
        }
        return addrs;
    }

    function conserved() public view virtual returns (uint256) {
        return _conserved;
    }

    function allConservedBy(address conservationist) public view virtual returns (uint256[] memory) {
        uint256 balance = balanceOf(conservationist);
        uint256[] memory tokens = new uint256[](balance);
        for (uint256 i = 0; i < balance; i++) {
            tokens[i] = tokenOfOwnerByIndex(conservationist, i);
        }
        return tokens;
    }

    function setConservationURI(string memory mintURI) public virtual conservationOwner {
        require(block.timestamp < _conservationLock, "Cannot update URI, maintenance window is closed");
        ERC721MetadataEnumerable._setTokenURI(mintURI);
    }

    function mintExclusive(address[] memory owners) public virtual conservationOwner {
        require(block.timestamp < _conservationLock, "Cannot mint exclusive, maintenance window is closed");
        uint256 exclusive = ERC721MetadataEnumerable.totalSupply() - _conserved;
        uint256 startingTokenId = ERC721MetadataEnumerable.totalSupply() + 1;
        // In the extremely improbable event that every mint is used for an exclusive, add 11 to take into
        // account the Ruby mints that provide an exclusive without being paired
        require((exclusive + owners.length) <= _conserved + 11, "Cannot mint an excess number of exclusives");

        for (uint256 i = 0; i < owners.length; i++) {
            ERC721MetadataEnumerable._safeMint(owners[i], startingTokenId + i, "");
        }
    }
}

// File: /contracts/contracts/ERC/ERC721MetadataEnumerable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.8;

import "./ERC165.sol";
import "../../interfaces/ERC/internal/IERC721Receiver.sol";
import "../../interfaces/ERC/internal/IERC721Metadata.sol";
import "../../interfaces/ERC/internal/IERC721Enumerable.sol";
import "../../interfaces/ERC/IERC721MetadataEnumerable.sol";
import "../../utils/Strings.sol";

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension and the Enumerable extension.
 */
contract ERC721MetadataEnumerable is ERC165, IERC721, IERC721Metadata, IERC721Enumerable, IERC721MetadataEnumerable {
    using Strings for uint256;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Token base URI
    string private _baseURI;

    // The total number of minted tokens
    uint256 private _totalSupply;

    // 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;

    // Mapping from owner to list of owned token IDs
    mapping(address => mapping(uint256 => uint256)) private _ownedTokens;

    // Mapping from token ID to index of the owner tokens list
    mapping(uint256 => uint256) private _ownedTokensIndex;

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

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            interfaceId == type(IERC721Enumerable).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "Cannot query balance 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), "Cannot query owner of token that does not exist");
        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), "Cannot query URI of token that does not exist");

        return string(abi.encodePacked(_baseURI, tokenId.toString()));
    }

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

    /**
     * @dev See {IERC721Enumerable-tokenByIndex}.
     */
    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
        require(index < _totalSupply, "Token index out of bounds");
        return index + 1;
    }

    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
        require(index < balanceOf(owner), "Owner token index out of bounds");
        return _ownedTokens[owner][index];
    }

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ownerOf(tokenId);
        require(to != owner, "Cannot give approval to current owner");

        require(
            msg.sender == owner || isApprovedForAll(owner, msg.sender),
            "Cannot give approval if caller is neither 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), "Cannot query approved of token that does not exist");

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        require(operator != msg.sender, "Cannot give approval to self");

        _operatorApprovals[msg.sender][operator] = approved;
        emit ApprovalForAll(msg.sender, 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 {
        require(_isApprovedOrOwner(msg.sender, tokenId), "Cannot transfer if caller is neither 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(msg.sender, tokenId), "Cannot transfer if caller is neither 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), "Cannot 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 can never be burned.
     */
    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), "Cannot query approved or owner of token that does not exist");
        address owner = ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
    }

    function _setTokenURI(string memory newTokenURI) internal virtual {
        _baseURI = newTokenURI;
    }

    /**
     * @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), "Cannot 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), "Cannot mint to the zero address");
        require(!_exists(tokenId), "Cannot mint a token that has already been minted");

        _addTokenToOwnerEnumeration(to, tokenId);

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

        emit Transfer(address(0), to, 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(ownerOf(tokenId) == from, "Cannot transfer token with different owner");
        require(to != address(0), "Cannot transfer to the zero address");
        require(from != address(0), "Cannot transfer from the zero address, must mint");

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

        _removeTokenFromOwnerEnumeration(from, tokenId);
        _addTokenToOwnerEnumeration(to, 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(ownerOf(tokenId), to, tokenId);
    }

    /**
     * @dev Private function to add a token to this extension's ownership-tracking data structures.
     * @param to address representing the new owner of the given token ID
     * @param tokenId uint256 ID of the token to be added to the tokens list of the given address
     */
    function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
        uint256 length = balanceOf(to);
        _ownedTokens[to][length] = tokenId;
        _ownedTokensIndex[tokenId] = length;
    }

    /**
     * @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that
     * while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for
     * gas optimizations e.g. when performing a transfer operation (avoiding double writes).
     * This has O(1) time complexity, but alters the order of the _ownedTokens array.
     * @param from address representing the previous owner of the given token ID
     * @param tokenId uint256 ID of the token to be removed from the tokens list of the given address
     */
    function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {
        // To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).
        uint256 lastTokenIndex = balanceOf(from) - 1;
        uint256 tokenIndex = _ownedTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary
        if (tokenIndex != lastTokenIndex) {
            uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];

            _ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
            _ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
        }

        // This also deletes the contents at the last position of the array
        delete _ownedTokensIndex[tokenId];
        delete _ownedTokens[from][lastTokenIndex];
    }

    /**
     * @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) {
        uint256 size;
        assembly {
            size := extcodesize(to)
        }
        if (size > 0) {
            try IERC721Receiver(to).onERC721Received(msg.sender, from, tokenId, _data) returns (bytes4 retval) {
                return retval == IERC721Receiver.onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("Cannot transfer to non ERC721Receiver implementer");
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }
}
// File: /contracts/contracts/ERC/ERC165.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.8;

import "../../interfaces/ERC/internal/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;
    }
}