// File: contracts/8bitshields.sol



// SPDX-License-Identifier: Unlicense

pragma solidity ^0.8.7;


import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "./factory.sol";

contract EIGHTBITSHIELDS is ERC721Enumerable, ReentrancyGuard, Ownable {

    uint256 private constant MAX_SHIELDS = 64;
    uint256 private constant FOUNDERS_RESERVE_AMOUNT = 24;

    string[] private backgrounds = [
        "Black",
        "Yellow",
        "Red",
        "Blue"
    ];

    string[] private checkerPatterns = [
        "Small",
        "Large"
    ];

    string[] private colors = [
        "Purple-Grey",
        "Blue-Grey",
        "Green-Grey",
        "Red-Blue"
    ];

    string[] private eights = [
        "Orange-Pink-Purple",
        "Yellow-Orange-Red"
    ];

    function getBackground(uint256 tokenId) public pure returns (uint256 retbackground) {
        uint256 curToken = tokenId - 1;
        uint256 background = (curToken / 16) % 4;
        return background;
    }

    function getCheckerPattern(uint256 tokenId) public pure returns (uint256 retcheckerPattern) {
        uint256 curToken = tokenId - 1;
        uint256 checkerPattern = (curToken / 8) % 2;
        return checkerPattern;
    }

    function getColor(uint256 tokenId) public pure returns (uint256 retcolor) {
        uint256 curToken = tokenId - 1;
        uint256 color = (curToken / 2) % 4;
        return color;
    }

    function getEight(uint256 tokenId) public pure returns (uint256 reteight) {
        uint256 curToken = tokenId - 1;
        uint256 eight = curToken % 2;  
        return eight;
    }

    function tokenURI(uint256 tokenId) public view override returns (string memory) {  
        string memory bg = backgrounds[(getBackground(tokenId))];
        string memory cp = checkerPatterns[(getCheckerPattern(tokenId))];
        string memory c = colors[(getColor(tokenId))];
        string memory e = eights[(getEight(tokenId))];

        string memory json = Base64.encode(bytes(string(abi.encodePacked('{"name": "SHIELDS #',   toString(tokenId), '", "description": "',  "8-Bit SHIELDS is a CC0 on-chain project for the 8 bit dao. Feel free to interpret 8-Bit SHIELDS for whatever you want. ", '", "image": "data:image/svg+xml;base64,', Base64.encode(bytes(factory.draw(getBackground(tokenId), getCheckerPattern(tokenId), getColor(tokenId), getEight(tokenId)))), '", "attributes": [{"trait_type": "Background", "value": "', bg,'"},{"trait_type": "Pattern", "value": "', cp,'"}, {"trait_type": "Colors","value": "', c,'"},{"trait_type": "Eight","value": "', e,'"}]}'))));
        string memory output = string(abi.encodePacked('data:application/json;base64,', json));
        return output;
    }

    function claim(uint8 tokenId) public nonReentrant {
        require(tokenId > FOUNDERS_RESERVE_AMOUNT && tokenId < MAX_SHIELDS + 1, "Token ID invalid");
        _safeMint(_msgSender(), tokenId);
    }
    
    function ownerClaim(uint8 tokenId) public nonReentrant onlyOwner {
        require(tokenId > 0 && tokenId < FOUNDERS_RESERVE_AMOUNT + 1, "Token ID invalid");
        _safeMint(owner(), tokenId);
    }


    function mint(uint8 tokenId) internal {
        _safeMint(msg.sender, tokenId);
    }    
    
    function toString(uint256 value) public pure returns (string memory) {
    // Inspired by OraclizeAPI's implementation - MIT license
    // 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);
    }
    constructor() ERC721("8BITSHIELDS", "8BITSHIELDS") Ownable() {}
}

/// [MIT License]
/// @title Base64
/// @notice Provides a function for encoding some bytes in base64
/// @author Brecht Devos <brecht@loopring.org>
library Base64 {
    bytes internal constant TABLE = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

    /// @notice Encodes some bytes to the base64 representation
    function encode(bytes memory data) internal pure returns (string memory) {
        uint256 len = data.length;
        if (len == 0) return "";

        // multiply by 4/3 rounded up
        uint256 encodedLen = 4 * ((len + 2) / 3);

        // Add some extra buffer at the end
        bytes memory result = new bytes(encodedLen + 32);

        bytes memory table = TABLE;

        assembly {
            let tablePtr := add(table, 1)
            let resultPtr := add(result, 32)

            for {
                let i := 0
            } lt(i, len) {

            } {
                i := add(i, 3)
                let input := and(mload(add(data, i)), 0xffffff)

                let out := mload(add(tablePtr, and(shr(18, input), 0x3F)))
                out := shl(8, out)
                out := add(out, and(mload(add(tablePtr, and(shr(12, input), 0x3F))), 0xFF))
                out := shl(8, out)
                out := add(out, and(mload(add(tablePtr, and(shr(6, input), 0x3F))), 0xFF))
                out := shl(8, out)
                out := add(out, and(mload(add(tablePtr, and(input, 0x3F))), 0xFF))
                out := shl(224, out)

                mstore(resultPtr, out)

                resultPtr := add(resultPtr, 4)
            }

            switch mod(len, 3)
            case 1 {
                mstore(sub(resultPtr, 2), shl(240, 0x3d3d))
            }
            case 2 {
                mstore(sub(resultPtr, 1), shl(248, 0x3d))
            }

            mstore(result, encodedLen)
        }

        return string(result);
    }
}
// File: @openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/ERC721Enumerable.sol)

pragma solidity ^0.8.0;

import "../ERC721.sol";
import "./IERC721Enumerable.sol";

/**
 * @dev This implements an optional extension of {ERC721} defined in the EIP that adds
 * enumerability of all the token ids in the contract as well as all token ids owned by each
 * account.
 */
abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
    // 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;

    // Array with all token ids, used for enumeration
    uint256[] private _allTokens;

    // Mapping from token id to position in the allTokens array
    mapping(uint256 => uint256) private _allTokensIndex;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
        return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721.balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
        return _ownedTokens[owner][index];
    }

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

    /**
     * @dev See {IERC721Enumerable-tokenByIndex}.
     */
    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721Enumerable.totalSupply(), "ERC721Enumerable: global index out of bounds");
        return _allTokens[index];
    }

    /**
     * @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` cannot be the zero address.
     * - `to` cannot be the zero address.
     *
     * 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 override {
        super._beforeTokenTransfer(from, to, tokenId);

        if (from == address(0)) {
            _addTokenToAllTokensEnumeration(tokenId);
        } else if (from != to) {
            _removeTokenFromOwnerEnumeration(from, tokenId);
        }
        if (to == address(0)) {
            _removeTokenFromAllTokensEnumeration(tokenId);
        } else if (to != from) {
            _addTokenToOwnerEnumeration(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 = ERC721.balanceOf(to);
        _ownedTokens[to][length] = tokenId;
        _ownedTokensIndex[tokenId] = length;
    }

    /**
     * @dev Private function to add a token to this extension's token tracking data structures.
     * @param tokenId uint256 ID of the token to be added to the tokens list
     */
    function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
        _allTokensIndex[tokenId] = _allTokens.length;
        _allTokens.push(tokenId);
    }

    /**
     * @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 = ERC721.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 Private function to remove a token from this extension's token tracking data structures.
     * This has O(1) time complexity, but alters the order of the _allTokens array.
     * @param tokenId uint256 ID of the token to be removed from the tokens list
     */
    function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {
        // To prevent a gap in the 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 = _allTokens.length - 1;
        uint256 tokenIndex = _allTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so
        // rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding
        // an 'if' statement (like in _removeTokenFromOwnerEnumeration)
        uint256 lastTokenId = _allTokens[lastTokenIndex];

        _allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
        _allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index

        // This also deletes the contents at the last position of the array
        delete _allTokensIndex[tokenId];
        _allTokens.pop();
    }
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// 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: contracts/factory.sol



// SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.7;

library factory {

  function draw(uint256 background, uint256 checkerPattern, uint256 color, uint256 eight) public pure returns (string memory) {
    
    string[4] memory backgrounds = [        
        ".bg{fill:#131016}",
        ".bg{fill:#ffaa31}",
        ".bg{fill:#b42c41}",
        ".bg{fill:#007fff}"
    ];

    string[4] memory  colors = [
        ".l{fill:#1d1036}.r{fill:#39206a}",
        ".l{fill:#202237}.r{fill:#242e5d}",
        ".l{fill:#334e74}.r{fill:#39987b}",
        ".l{fill:#18226d}.r{fill:#b42c41}"
    ];

    string[2]  memory eights = [
        ".B{fill:#131016}.C{fill:#ee2073}.D{fill:#ffaa31}.E{fill:#39206a}",
        ".B{fill:#131016}.C{fill:#fd9d35}.D{fill:#fcea44}.E{fill:#fc6340}"
    ];
    
    string memory bg = backgrounds[background];
    string memory c = colors[color];
    string memory e = eights[eight];
    
    string memory eightDraw = _getEights();
    string memory outline = _getOutline();
    string memory backgroundDraw = _getBackground();
    string memory closeStyle = ']]></style><g id="image" transform="scale(4 4)">';     
    string memory s = _getShield(checkerPattern);

    return string(abi.encodePacked('<svg version="1.1" width="160" height="160" xmlns="http://www.w3.org/2000/svg" shape-rendering="crispEdges"><style><![CDATA[',bg,c,e,closeStyle,backgroundDraw,s,eightDraw,outline,'</g></svg>'));
    
  }

  function _getShield(uint256 checkerPattern) internal pure returns (string memory) {      
     if (checkerPattern == 0) {
       return _getBigShield();
     } else {       
       return _getSmallShield();
     }
  }

  function _getBackground() internal pure returns (string memory) {
    string memory background = '<rect x="0" y="0" width="40" height="40" class="bg"/>';
      return background;
  }
  function _getBigShield() internal pure returns (string memory) {
    string memory shield = '<rect x="7" y="4" width="13" height="15" class="l" />'
            '<rect x="8" y="3" width="12" height="1" class="l" />'
            '<rect x="6" y="5" width="1" height="14" class="l" />'
            '<rect x="20" y="19" width="14" height="9" class="l" />'
            '<rect x="20" y="28" width="13" height="1" class="l" />'
            '<rect x="20" y="29" width="12" height="1" class="l" />'
            '<rect x="20" y="30" width="11" height="1" class="l" />'
            '<rect x="20" y="31" width="10" height="1" class="l" />'
            '<rect x="20" y="32" width="9" height="1" class="l" />'
            '<rect x="20" y="33" width="8" height="1" class="l" />'
            '<rect x="20" y="34" width="7" height="1" class="l" />'
            '<rect x="20" y="35" width="6" height="1" class="l" />'
            '<rect x="20" y="36" width="5" height="1" class="l" />'
            '<rect x="20" y="37" width="4" height="1" class="l" />'
            '<rect x="20" y="3" width="12" height="1" class="r" />'
            '<rect x="20" y="4" width="13" height="15" class="r" />'
            '<rect x="33" y="5" width="1" height="14" class="r" />'
            '<rect x="6" y="19" width="14" height="9" class="r" />'
            '<rect x="7" y="28" width="13" height="1" class="r" />'
            '<rect x="8" y="29" width="12" height="1" class="r" />'
            '<rect x="9" y="30" width="11" height="1" class="r" />'
            '<rect x="10" y="31" width="10" height="1" class="r" />'
            '<rect x="11" y="32" width="9" height="1" class="r" />'
            '<rect x="12" y="33" width="8" height="1" class="r" />'
            '<rect x="13" y="34" width="7" height="1" class="r" />'
            '<rect x="14" y="35" width="6" height="1" class="r" />'
            '<rect x="15" y="36" width="5" height="1" class="r" />'
            '<rect x="16" y="37" width="4" height="1" class="r" />';
      return shield;
  }

    function _getSmallShield() internal pure returns (string memory) {
    string memory shield = '<rect x="7" y="4" width="13" height="15" class="l" />'
            '<rect x="8" y="3" width="12" height="1" class="l" />'
            '<rect x="6" y="5" width="1" height="14" class="l" />'
            '<rect x="20" y="19" width="14" height="9" class="l" />'
            '<rect x="20" y="28" width="13" height="1" class="l" />'
            '<rect x="20" y="29" width="12" height="1" class="l" />'
            '<rect x="20" y="30" width="11" height="1" class="l" />'
            '<rect x="20" y="31" width="10" height="1" class="l" />'
            '<rect x="20" y="32" width="9" height="1" class="l" />'
            '<rect x="20" y="33" width="8" height="1" class="l" />'
            '<rect x="20" y="34" width="7" height="1" class="l" />'
            '<rect x="20" y="35" width="6" height="1" class="l" />'
            '<rect x="20" y="36" width="5" height="1" class="l" />'
            '<rect x="20" y="37" width="4" height="1" class="l" />'
            '<rect x="20" y="3" width="12" height="1" class="l" />'
            '<rect x="20" y="4" width="13" height="15" class="l" />'
            '<rect x="33" y="5" width="1" height="14" class="l" />'
            '<rect x="6" y="19" width="14" height="9" class="l" />'
            '<rect x="7" y="28" width="13" height="1" class="l" />'
            '<rect x="8" y="29" width="12" height="1" class="l" />'
            '<rect x="9" y="30" width="11" height="1" class="l" />'
            '<rect x="10" y="31" width="10" height="1" class="l" />'
            '<rect x="11" y="32" width="9" height="1" class="l" />'
            '<rect x="12" y="33" width="8" height="1" class="l" />'
            '<rect x="13" y="34" width="7" height="1" class="l" />'
            '<rect x="14" y="35" width="6" height="1" class="l" />'
            '<rect x="15" y="36" width="6" height="1" class="l" />'
            '<rect x="16" y="37" width="4" height="1" class="l" />'
            '<rect x="10" y="3" width="4" height="4" class="r" />'
            '<rect x="18" y="3" width="4" height="4" class="r" />'
            '<rect x="26" y="3" width="4" height="4" class="r" />'
            '<rect x="14" y="7" width="4" height="4" class="r" />'
            '<rect x="22" y="7" width="4" height="4" class="r" />'
            '<rect x="30" y="7" width="4" height="4" class="r" />'
            '<rect x="10" y="11" width="4" height="4" class="r" />'
            '<rect x="18" y="11" width="4" height="4" class="r" />'
            '<rect x="26" y="11" width="4" height="4" class="r" />'
            '<rect x="6" y="15" width="4" height="4" class="r" />'
            '<rect x="14" y="15" width="4" height="4" class="r" />'
            '<rect x="22" y="15" width="4" height="4" class="r" />'
            '<rect x="30" y="15" width="4" height="4" class="r" />'
            '<rect x="10" y="19" width="4" height="4" class="r" />'
            '<rect x="18" y="19" width="4" height="4" class="r" />'
            '<rect x="26" y="19" width="4" height="4" class="r" />'
            '<rect x="6" y="23" width="4" height="4" class="r" />'
            '<rect x="14" y="23" width="4" height="4" class="r" />'
            '<rect x="22" y="23" width="4" height="4" class="r" />'
            '<rect x="30" y="23" width="4" height="4" class="r" />'
            '<rect x="10" y="27" width="4" height="4" class="r" />'
            '<rect x="18" y="27" width="4" height="4" class="r" />'
            '<rect x="26" y="27" width="4" height="4" class="r" />'
            '<rect x="14" y="31" width="4" height="4" class="r" />'
            '<rect x="22" y="31" width="4" height="4" class="r" />'
            '<rect x="18" y="35" width="4" height="3" class="r" />';

      return shield;
  }

    function _getOutline() internal pure returns (string memory) {
    string memory outline = '<rect x="8" y="2" width="24" height="1" fill="#202237" />'
        '<rect x="7" y="3" width="1" height="1" fill="#202237" />'
        '<rect x="32" y="3" width="1" height="1" fill="#202237" />'
        '<rect x="6" y="4" width="1" height="1" fill="#202237" />'
        '<rect x="33" y="4" width="1" height="1" fill="#202237" />'
        '<rect x="5" y="5" width="1" height="23" fill="#202237" />'
        '<rect x="34" y="5" width="1" height="23" fill="#202237" />'
        '<rect x="6" y="28" width="1" height="1" fill="#202237" />'
        '<rect x="33" y="28" width="1" height="1" fill="#202237" />'
        '<rect x="7" y="29" width="1" height="1" fill="#202237" />'
        '<rect x="32" y="29" width="1" height="1" fill="#202237" />'
        '<rect x="8" y="30" width="1" height="1" fill="#202237" />'
        '<rect x="31" y="30" width="1" height="1" fill="#202237" />'
        '<rect x="9" y="31" width="1" height="1" fill="#202237" />'
        '<rect x="30" y="31" width="1" height="1" fill="#202237" />'
        '<rect x="10" y="32" width="1" height="1" fill="#202237" />'
        '<rect x="29" y="32" width="1" height="1" fill="#202237" />'
        '<rect x="11" y="33" width="1" height="1" fill="#202237" />'
        '<rect x="28" y="33" width="1" height="1" fill="#202237" />'
        '<rect x="12" y="34" width="1" height="1" fill="#202237" />'
        '<rect x="27" y="34" width="1" height="1" fill="#202237" />'
        '<rect x="13" y="35" width="1" height="1" fill="#202237" />'
        '<rect x="26" y="35" width="1" height="1" fill="#202237" />'
        '<rect x="14" y="36" width="1" height="1" fill="#202237" />'
        '<rect x="25" y="36" width="1" height="1" fill="#202237" />'
        '<rect x="15" y="37" width="1" height="1" fill="#202237" />'
        '<rect x="24" y="37" width="1" height="1" fill="#202237" />'
        '<rect x="16" y="38" width="8" height="1" fill="#202237" />';
      return outline;
  }

  function _getEights() internal pure returns (string memory) {
    string memory eight = '<path d="M15 3h1v1h-1z" class="B"/><g class="D"><path d="M16 3h1v1h-1z"/><path d="M17 3h1v1h-1z"/><path d="M18 3h1v1h-1z"/></g><g class="B"><path d="M19 3h1v1h-1z"/><path d="M20 3h1v1h-1z"/></g><g class="D"><path d="M21 3h1v1h-1z"/><path d="M22 3h1v1h-1z"/><path d="M23 3h1v1h-1z"/></g><path d="M24 3h1v1h-1zm-9 1h1v1h-1z" class="B"/><path d="M16 4h1v1h-1z" class="C"/><path d="M17 4h1v1h-1z" class="D"/><path d="M18 4h1v1h-1z" class="C"/><g class="B"><path d="M19 4h1v1h-1z"/><path d="M20 4h1v1h-1z"/></g><path d="M21 4h1v1h-1z" class="C"/><path d="M22 4h1v1h-1z" class="D"/><path d="M23 4h1v1h-1z" class="C"/><path d="M24 4h1v1h-1zm-8 1h1v1h-1z" class="B"/><path d="M17 5h1v1h-1z" class="C"/><path d="M18 5h1v1h-1z" class="D"/><g class="C"><path d="M19 5h1v1h-1z"/><path d="M20 5h1v1h-1z"/></g><path d="M21 5h1v1h-1z" class="D"/><path d="M22 5h1v1h-1z" class="C"/><path d="M23 5h1v1h-1zm-6 1h1v1h-1z" class="B"/><g class="C"><path d="M18 6h1v1h-1z"/><path d="M19 6h1v1h-1z"/><path d="M20 6h1v1h-1z"/><path d="M21 6h1v1h-1z"/></g><path d="M22 6h1v1h-1zm-6 1h1v1h-1z" class="B"/><path d="M17 7h1v1h-1z" class="C"/><path d="M18 7h1v1h-1z" class="E"/><g class="C"><path d="M19 7h1v1h-1z"/><path d="M20 7h1v1h-1z"/></g><path d="M21 7h1v1h-1z" class="E"/><path d="M22 7h1v1h-1z" class="C"/><path d="M23 7h1v1h-1zm-8 1h1v1h-1z" class="B"/><path d="M16 8h1v1h-1z" class="C"/><path d="M17 8h1v1h-1z" class="E"/><path d="M18 8h1v1h-1z" class="C"/><g class="B"><path d="M19 8h1v1h-1z"/><path d="M20 8h1v1h-1z"/></g><path d="M21 8h1v1h-1z" class="C"/><path d="M22 8h1v1h-1z" class="E"/><path d="M23 8h1v1h-1z" class="C"/><path d="M24 8h1v1h-1zm-9 1h1v1h-1z" class="B"/><g class="E"><path d="M16 9h1v1h-1z"/><path d="M17 9h1v1h-1z"/><path d="M18 9h1v1h-1z"/></g><g class="B"><path d="M19 9h1v1h-1z"/><path d="M20 9h1v1h-1z"/></g><g class="E"><path d="M21 9h1v1h-1z"/><path d="M22 9h1v1h-1z"/><path d="M23 9h1v1h-1z"/></g><path d="M24 9h1v1h-1zm-9 1h1v1h-1z" class="B"/><g class="E"><path d="M16 10h1v1h-1z"/><path d="M17 10h1v1h-1z"/><path d="M18 10h1v1h-1z"/></g><g class="B"><path d="M19 10h1v1h-1z"/><path d="M20 10h1v1h-1z"/></g><g class="E"><path d="M21 10h1v1h-1z"/><path d="M22 10h1v1h-1z"/><path d="M23 10h1v1h-1z"/></g><path d="M24 10h1v1h-1zm-8 1h1v1h-1z" class="B"/><g class="E"><path d="M17 11h1v1h-1z"/><path d="M18 11h1v1h-1z"/><path d="M19 11h1v1h-1z"/><path d="M20 11h1v1h-1z"/><path d="M21 11h1v1h-1z"/><path d="M22 11h1v1h-1z"/></g><path d="M23 11h1v1h-1zm-6 1h1v1h-1z" class="B"/><g class="E"><path d="M18 12h1v1h-1z"/><path d="M19 12h1v1h-1z"/><path d="M20 12h1v1h-1z"/><path d="M21 12h1v1h-1z"/></g><g class="B"><path d="M22 12h1v1h-1zm-4 1h1v1h-1z"/><path d="M19 13h1v1h-1z"/><path d="M20 13h1v1h-1z"/><path d="M21 13h1v1h-1zm-4 1h1v1h-1z"/></g><g class="D"><path d="M18 14h1v1h-1z"/><path d="M19 14h1v1h-1z"/><path d="M20 14h1v1h-1z"/><path d="M21 14h1v1h-1z"/></g><path d="M22 14h1v1h-1zm-6 1h1v1h-1z" class="B"/><g class="D"><path d="M17 15h1v1h-1z"/><path d="M18 15h1v1h-1z"/><path d="M19 15h1v1h-1z"/><path d="M20 15h1v1h-1z"/><path d="M21 15h1v1h-1z"/><path d="M22 15h1v1h-1z"/></g><path d="M23 15h1v1h-1zm-8 1h1v1h-1z" class="B"/><g class="D"><path d="M16 16h1v1h-1z"/><path d="M17 16h1v1h-1z"/><path d="M18 16h1v1h-1z"/></g><g class="B"><path d="M19 16h1v1h-1z"/><path d="M20 16h1v1h-1z"/></g><g class="D"><path d="M21 16h1v1h-1z"/><path d="M22 16h1v1h-1z"/><path d="M23 16h1v1h-1z"/></g><path d="M24 16h1v1h-1zm-9 1h1v1h-1z" class="B"/><g class="D"><path d="M16 17h1v1h-1z"/><path d="M17 17h1v1h-1z"/><path d="M18 17h1v1h-1z"/></g><g class="B"><path d="M19 17h1v1h-1z"/><path d="M20 17h1v1h-1z"/></g><g class="D"><path d="M21 17h1v1h-1z"/><path d="M22 17h1v1h-1z"/><path d="M23 17h1v1h-1z"/></g><path d="M24 17h1v1h-1zm-9 1h1v1h-1z" class="B"/><path d="M16 18h1v1h-1z" class="C"/><path d="M17 18h1v1h-1z" class="D"/><path d="M18 18h1v1h-1z" class="C"/><g class="B"><path d="M19 18h1v1h-1z"/><path d="M20 18h1v1h-1z"/></g><path d="M21 18h1v1h-1z" class="C"/><path d="M22 18h1v1h-1z" class="D"/><path d="M23 18h1v1h-1z" class="C"/><path d="M24 18h1v1h-1zm-8 1h1v1h-1z" class="B"/><path d="M17 19h1v1h-1z" class="C"/><path d="M18 19h1v1h-1z" class="D"/><g class="C"><path d="M19 19h1v1h-1z"/><path d="M20 19h1v1h-1z"/></g><path d="M21 19h1v1h-1z" class="D"/><path d="M22 19h1v1h-1z" class="C"/><path d="M23 19h1v1h-1zm-6 1h1v1h-1z" class="B"/><g class="C"><path d="M18 20h1v1h-1z"/><path d="M19 20h1v1h-1z"/><path d="M20 20h1v1h-1z"/><path d="M21 20h1v1h-1z"/></g><path d="M22 20h1v1h-1zm-6 1h1v1h-1z" class="B"/><path d="M17 21h1v1h-1z" class="C"/><path d="M18 21h1v1h-1z" class="E"/><g class="C"><path d="M19 21h1v1h-1z"/><path d="M20 21h1v1h-1z"/></g><path d="M21 21h1v1h-1z" class="E"/><path d="M22 21h1v1h-1z" class="C"/><path d="M23 21h1v1h-1zm-8 1h1v1h-1z" class="B"/><path d="M16 22h1v1h-1z" class="C"/><path d="M17 22h1v1h-1z" class="E"/><path d="M18 22h1v1h-1z" class="C"/><g class="B"><path d="M19 22h1v1h-1z"/><path d="M20 22h1v1h-1z"/></g><path d="M21 22h1v1h-1z" class="C"/><path d="M22 22h1v1h-1z" class="E"/><path d="M23 22h1v1h-1z" class="C"/><path d="M24 22h1v1h-1zm-9 1h1v1h-1z" class="B"/><g class="E"><path d="M16 23h1v1h-1z"/><path d="M17 23h1v1h-1z"/><path d="M18 23h1v1h-1z"/></g><g class="B"><path d="M19 23h1v1h-1z"/><path d="M20 23h1v1h-1z"/></g><g class="E"><path d="M21 23h1v1h-1z"/><path d="M22 23h1v1h-1z"/><path d="M23 23h1v1h-1z"/></g><path d="M24 23h1v1h-1zm-9 1h1v1h-1z" class="B"/><g class="E"><path d="M16 24h1v1h-1z"/><path d="M17 24h1v1h-1z"/><path d="M18 24h1v1h-1z"/></g><g class="B"><path d="M19 24h1v1h-1z"/><path d="M20 24h1v1h-1z"/></g><g class="E"><path d="M21 24h1v1h-1z"/><path d="M22 24h1v1h-1z"/><path d="M23 24h1v1h-1z"/></g><path d="M24 24h1v1h-1zm-8 1h1v1h-1z" class="B"/><g class="E"><path d="M17 25h1v1h-1z"/><path d="M18 25h1v1h-1z"/><path d="M19 25h1v1h-1z"/><path d="M20 25h1v1h-1z"/><path d="M21 25h1v1h-1z"/><path d="M22 25h1v1h-1z"/></g><path d="M23 25h1v1h-1zm-6 1h1v1h-1z" class="B"/><g class="E"><path d="M18 26h1v1h-1z"/><path d="M19 26h1v1h-1z"/><path d="M20 26h1v1h-1z"/><path d="M21 26h1v1h-1z"/></g><g class="B"><path d="M22 26h1v1h-1zm-4 1h1v1h-1z"/><path d="M19 27h1v1h-1z"/><path d="M20 27h1v1h-1z"/><path d="M21 27h1v1h-1zm-4 1h1v1h-1z"/></g><g class="D"><path d="M18 28h1v1h-1z"/><path d="M19 28h1v1h-1z"/><path d="M20 28h1v1h-1z"/><path d="M21 28h1v1h-1z"/></g><path d="M22 28h1v1h-1zm-6 1h1v1h-1z" class="B"/><g class="D"><path d="M17 29h1v1h-1z"/><path d="M18 29h1v1h-1z"/><path d="M19 29h1v1h-1z"/><path d="M20 29h1v1h-1z"/><path d="M21 29h1v1h-1z"/><path d="M22 29h1v1h-1z"/></g><path d="M23 29h1v1h-1zm-8 1h1v1h-1z" class="B"/><g class="D"><path d="M16 30h1v1h-1z"/><path d="M17 30h1v1h-1z"/><path d="M18 30h1v1h-1z"/></g><g class="B"><path d="M19 30h1v1h-1z"/><path d="M20 30h1v1h-1z"/></g><g class="D"><path d="M21 30h1v1h-1z"/><path d="M22 30h1v1h-1z"/><path d="M23 30h1v1h-1z"/></g><path d="M24 30h1v1h-1zm-9 1h1v1h-1z" class="B"/><g class="D"><path d="M16 31h1v1h-1z"/><path d="M17 31h1v1h-1z"/><path d="M18 31h1v1h-1z"/></g><g class="B"><path d="M19 31h1v1h-1z"/><path d="M20 31h1v1h-1z"/></g><g class="D"><path d="M21 31h1v1h-1z"/><path d="M22 31h1v1h-1z"/><path d="M23 31h1v1h-1z"/></g><path d="M24 31h1v1h-1zm-9 1h1v1h-1z" class="B"/><path d="M16 32h1v1h-1z" class="C"/><path d="M17 32h1v1h-1z" class="D"/><path d="M18 32h1v1h-1z" class="C"/><g class="B"><path d="M19 32h1v1h-1z"/><path d="M20 32h1v1h-1z"/></g><path d="M21 32h1v1h-1z" class="C"/><path d="M22 32h1v1h-1z" class="D"/><path d="M23 32h1v1h-1z" class="C"/><path d="M24 32h1v1h-1zm-8 1h1v1h-1z" class="B"/><path d="M17 33h1v1h-1z" class="C"/><path d="M18 33h1v1h-1z" class="D"/><g class="C"><path d="M19 33h1v1h-1z"/><path d="M20 33h1v1h-1z"/></g><path d="M21 33h1v1h-1z" class="D"/><path d="M22 33h1v1h-1z" class="C"/><path d="M23 33h1v1h-1zm-6 1h1v1h-1z" class="B"/><g class="C"><path d="M18 34h1v1h-1z"/><path d="M19 34h1v1h-1z"/><path d="M20 34h1v1h-1z"/><path d="M21 34h1v1h-1z"/></g><path d="M22 34h1v1h-1zm-6 1h1v1h-1z" class="B"/><path d="M17 35h1v1h-1z" class="C"/><path d="M18 35h1v1h-1z" class="E"/><g class="C"><path d="M19 35h1v1h-1z"/><path d="M20 35h1v1h-1z"/></g><path d="M21 35h1v1h-1z" class="E"/><path d="M22 35h1v1h-1z" class="C"/><path d="M23 35h1v1h-1zm-8 1h1v1h-1z" class="B"/><path d="M16 36h1v1h-1z" class="C"/><path d="M17 36h1v1h-1z" class="E"/><path d="M18 36h1v1h-1z" class="C"/><g class="B"><path d="M19 36h1v1h-1z"/><path d="M20 36h1v1h-1z"/></g><path d="M21 36h1v1h-1z" class="C"/><path d="M22 36h1v1h-1z" class="E"/><path d="M23 36h1v1h-1z" class="C"/><path d="M24 36h1v1h-1zm-9 1h1v1h-1z" class="B"/><g class="E"><path d="M16 37h1v1h-1z"/><path d="M17 37h1v1h-1z"/><path d="M18 37h1v1h-1z"/></g><g class="B"><path d="M19 37h1v1h-1z"/><path d="M20 37h1v1h-1z"/></g><g class="E"><path d="M21 37h1v1h-1z"/><path d="M22 37h1v1h-1z"/><path d="M23 37h1v1h-1z"/></g><path d="M24 37h1v1h-1z" class="B"/>';
      return eight;
  }
  
}
// 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/token/ERC721/extensions/IERC721Enumerable.sol



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

pragma solidity ^0.8.0;

import "../IERC721.sol";

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

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

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

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



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

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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



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

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

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



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

pragma solidity ^0.8.0;

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

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

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

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

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

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