creation_sourcecode: {{
    "language": "Solidity",
    "sources": {
      "SubscriptionService.sol": {
        "content": "// SPDX-License-Identifier: UNLICENSED\npragma solidity ^0.8.2;\n\nimport \"ERC721Enumerable.sol\";\nimport \"Ownable.sol\";\nimport \"SubJsonParser.sol\";\n\ncontract SubscriptionService is ERC721Enumerable, Ownable, SubJsonParser {\n\n\tstruct SubData {\n\t\tuint32 tier;\n\t\tuint32 start;\n\t\tuint32 length;\n\t}\n\n\tuint256 public constant MAX = 500;\n\tuint256 public maxSupply = 300;\n\tbool public paused;\n\tuint32 public counter;\n\n\tuint256[3] public subPrice;\n\tuint256 buyCounter;\n\n\tmapping(uint256 => uint256) expiredStack;\n\tuint256 expiredCounter;\n\tmapping(uint256 => SubData) public subData;\n\tmapping(address => bool) public authorisedCaller;\n\n\tbool public initiated;\n\n\tbool public buySwitch;\n\n\tevent SubBought(address indexed buyer, uint256 indexed tokenId, uint32 tier, uint256 value);\n\n\tconstructor(string memory _name, string memory _symbol)  ERC721(_name, _symbol) {}\n\n\tfunction init (string memory __name, string memory __symbol) external {\n\t\trequire(!initiated);\n\t\tinitiated = true;\n\t\tpaused = false;\n\t\tsubPrice[0] = 1_950_000_000_000_000_000;\n\t\tsubPrice[1] = 3_705_000_000_000_000_000;\n\t\tsubPrice[2] = 5_265_000_000_000_000_000;\n\n\t\tcounter = 1;\n\t\t_name = __name;\n\t\t_symbol = __symbol;\n\t\t_owner = msg.sender;\n\t}\n\n\tmodifier notPaused() {\n\t\trequire(!paused, \"Paused\");\n\t\t_;\n\t}\n\n\tmodifier authorised() {\n\t\trequire(authorisedCaller[msg.sender] || msg.sender == owner(), \"Not authorised to execute.\");\n\t\t_;\n\t}\n\n\tmodifier nonBuyable() {\n\t\trequire(!buySwitch, \"Not authorised to buy.\");\n\t\t_;\n\t}\n\n\tfunction setCaller(address _caller, bool _value) external onlyOwner {\n\t\tauthorisedCaller[_caller] = _value;\n\t}\n\n\tfunction fetchEth() external onlyOwner {\n\t\tpayable(owner()).transfer(address(this).balance);\n\t}\n\n\tfunction pause() external onlyOwner {\n\t\tpaused = true;\n\t}\n\n\tfunction unpause() external onlyOwner {\n\t\tpaused = false;\n\t}\n\n\tfunction switchIt() external onlyOwner {\n\t\tbuySwitch = !buySwitch;\n\t}\n\n\tfunction pushNewBox() external authorised {\n\t\tcounter++;\n\t}\n\n\tfunction setPrice(uint256 _index, uint256 _price) external onlyOwner {\n\t\tsubPrice[_index] = _price;\n\t}\n\n\tfunction setMaxSupply(uint256 _max) external onlyOwner {\n\t\trequire(_max <= MAX);\n\t\tmaxSupply = _max;\n\t}\n\n\tfunction refundSub(uint256 _tokenId) external onlyOwner {\n\t\trequire(!isExpired(_tokenId), \"Expired\");\n\t\tSubData memory data = subData[_tokenId];\n\t\texpiredStack[expiredCounter++] = _tokenId;\n\t\tdelete subData[_tokenId];\n\t\t_burn(_tokenId);\n\t}\n\n\tfunction expireSub(uint256 _tokenId) external {\n\t\trequire(isExpired(_tokenId), \"Not expired\");\n\t\texpiredStack[expiredCounter++] = _tokenId;\n\t\tdelete subData[_tokenId];\n\t\t_burn(_tokenId);\n\t}\n\n\tfunction buySub(uint8 _tier) external payable {\n\t\tbuySub(_tier, msg.sender);\n\t}\n\n\tfunction buySubOwner(uint8 _tier, address _for) public authorised {\n\t\t// require(_tier == 0 || _tier == 1 || _tier == 2, \"Sub: Wrong sub model\");\n\t\trequire(_tier == 0, \"Sub: Wrong sub model\");\n\t\trequire(totalSupply() < maxSupply, \"No more subs of that tier to buy\");\n\n\t\tif (buyCounter < MAX) {\n\t\t\tsubData[++buyCounter] = SubData(_tier, counter, _getLength(_tier));\n\t\t\t_mint(_for, buyCounter);\n\t\t\temit SubBought(_for, buyCounter, _tier, 1);\n\t\t}\n\t\telse {\n\t\t\trequire(expiredCounter > 0, \"No subs available, try next month\");\n\t\t\tuint256 id = expiredStack[--expiredCounter];\n\t\t\tsubData[id] = SubData(_tier, counter, _getLength(_tier));\n\t\t\t_mint(_for, id);\n\t\t\temit SubBought(_for, id, _tier, 1);\n\t\t}\n\t}\n\n\tfunction buySub(uint8 _tier, address _for) public payable nonBuyable {\n\t\t// require(_tier == 0 || _tier == 1 || _tier == 2, \"Sub: Wrong sub model\");\n\t\trequire(_tier == 0, \"Sub: Wrong sub model\");\n\t\trequire(totalSupply() < maxSupply, \"No more subs of that tier to buy\");\n\t\trequire(msg.value == subPrice[_tier], \"!price\");\n\n\t\tif (buyCounter < MAX) {\n\t\t\tsubData[++buyCounter] = SubData(_tier, counter, _getLength(_tier));\n\t\t\t_mint(_for, buyCounter);\n\t\t\temit SubBought(_for, buyCounter, _tier, msg.value);\n\t\t}\n\t\telse {\n\t\t\trequire(expiredCounter > 0, \"No subs available, try next month\");\n\t\t\tuint256 id = expiredStack[--expiredCounter];\n\t\t\tsubData[id] = SubData(_tier, counter, _getLength(_tier));\n\t\t\t_mint(_for, id);\n\t\t\temit SubBought(_for, id, _tier, msg.value);\n\t\t}\n\t}\n\n\tfunction isExpired(uint256 _tokenId) public view returns(bool) {\n\t\tSubData memory data = subData[_tokenId];\n\t\treturn data.start + data.length <= counter;\n\t}\n\n\tfunction _getType(uint32 _length) internal pure returns(uint256) {\n\t\tif (_length == 3)\n\t\t\treturn 0;\n\t\telse if (_length == 6)\n\t\t\treturn 1;\n\t\tif (_length == 9)\n\t\t\treturn 2;\n\t\treturn 0;\n\t}\n\n\tfunction _getLength(uint8 _type) internal pure returns(uint32) {\n\t\tif (_type == uint8(0))\n\t\t\treturn uint32(3);\n\t\telse if (_type == uint8(1))\n\t\t\treturn uint32(6);\n\t\tif (_type == uint8(2))\n\t\t\treturn uint32(9);\n\t\treturn 0;\n\t}\n\n\tfunction fetchValidHolders(uint256 _start, uint256 _len) external view returns(address[] memory holders) {\n\t\tholders = new address[](_len);\n\t\tfor (uint256 i = _start; i < _start + _len; i++) {\n\t\t\tif (_exists(i)) {\n\t\t\t\taddress owner = ownerOf(i);\n\t\t\t\tif (!isExpired(i))\n\t\t\t\t\tholders[i - _start] = ownerOf(i);\n\t\t\t}\n\t\t}\n\t}\n\n\tfunction returnSubDataOfHolder(address _holder) external view returns(SubData[] memory data) {\n\t\tuint256 amount = balanceOf(_holder);\n\t\tdata = new SubData[](amount);\n\t\tfor (uint256 i = 0; i < amount; i++) {\n\t\t\tdata[i] = subData[tokenOfOwnerByIndex(_holder, i)];\n\t\t}\n\t}\n\n\tfunction hasUserSub(address _holder, uint256 _tierId) external view returns(bool) {\n\t\tuint256 amount = balanceOf(_holder);\n\t\tfor (uint256 i = 0; i < amount; i++) {\n\t\t\tuint256 tokenId = tokenOfOwnerByIndex(_holder, i);\n\t\t\tSubData memory data = subData[tokenId];\n\t\t\tif (data.tier == _tierId && !isExpired(tokenId))\n\t\t\t\treturn true;\n\t\t}\n\t\treturn false;\n\t}\n\n\tfunction _transfer(address from, address to, uint256 tokenId) internal override notPaused {\n\t\tsuper._transfer(from, to, tokenId);\n\t}\n\n\n\tfunction tokenURI(uint256 _tokenId) public view override returns(string memory) {\n\t\tSubData memory data = subData[_tokenId];\n\t\trequire(_exists(_tokenId));\n\t\treturn string(\n\t\t\tabi.encodePacked(\n\t\t\t\tgenerateTokenUriPart1(_tokenId, uint256(data.tier)),\n\t\t\t\tgenerateTokenUriPart2(_getLength(uint8(data.tier)), counter, data.start, data.length)\n\t\t\t)\n\t\t);\n\t}\n}"
      },
      "ERC721Enumerable.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/ERC721Enumerable.sol)\n\npragma solidity ^0.8.0;\n\nimport \"ERC721.sol\";\nimport \"IERC721Enumerable.sol\";\n\n/**\n * @dev This implements an optional extension of {ERC721} defined in the EIP that adds\n * enumerability of all the token ids in the contract as well as all token ids owned by each\n * account.\n */\nabstract contract ERC721Enumerable is ERC721, IERC721Enumerable {\n    // Mapping from owner to list of owned token IDs\n    mapping(address => mapping(uint256 => uint256)) private _ownedTokens;\n\n    // Mapping from token ID to index of the owner tokens list\n    mapping(uint256 => uint256) private _ownedTokensIndex;\n\n    // Array with all token ids, used for enumeration\n    uint256[] private _allTokens;\n\n    // Mapping from token id to position in the allTokens array\n    mapping(uint256 => uint256) private _allTokensIndex;\n\n    /**\n     * @dev See {IERC165-supportsInterface}.\n     */\n    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {\n        return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);\n    }\n\n    /**\n     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.\n     */\n    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {\n        require(index < ERC721.balanceOf(owner), \"ERC721Enumerable: owner index out of bounds\");\n        return _ownedTokens[owner][index];\n    }\n\n    /**\n     * @dev See {IERC721Enumerable-totalSupply}.\n     */\n    function totalSupply() public view virtual override returns (uint256) {\n        return _allTokens.length;\n    }\n\n    /**\n     * @dev See {IERC721Enumerable-tokenByIndex}.\n     */\n    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {\n        require(index < ERC721Enumerable.totalSupply(), \"ERC721Enumerable: global index out of bounds\");\n        return _allTokens[index];\n    }\n\n    /**\n     * @dev Hook that is called before any token transfer. This includes minting\n     * and burning.\n     *\n     * Calling conditions:\n     *\n     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be\n     * transferred to `to`.\n     * - When `from` is zero, `tokenId` will be minted for `to`.\n     * - When `to` is zero, ``from``'s `tokenId` will be burned.\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     *\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n     */\n    function _beforeTokenTransfer(\n        address from,\n        address to,\n        uint256 tokenId\n    ) internal virtual override {\n        super._beforeTokenTransfer(from, to, tokenId);\n\n        if (from == address(0)) {\n            _addTokenToAllTokensEnumeration(tokenId);\n        } else if (from != to) {\n            _removeTokenFromOwnerEnumeration(from, tokenId);\n        }\n        if (to == address(0)) {\n            _removeTokenFromAllTokensEnumeration(tokenId);\n        } else if (to != from) {\n            _addTokenToOwnerEnumeration(to, tokenId);\n        }\n    }\n\n    /**\n     * @dev Private function to add a token to this extension's ownership-tracking data structures.\n     * @param to address representing the new owner of the given token ID\n     * @param tokenId uint256 ID of the token to be added to the tokens list of the given address\n     */\n    function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {\n        uint256 length = ERC721.balanceOf(to);\n        _ownedTokens[to][length] = tokenId;\n        _ownedTokensIndex[tokenId] = length;\n    }\n\n    /**\n     * @dev Private function to add a token to this extension's token tracking data structures.\n     * @param tokenId uint256 ID of the token to be added to the tokens list\n     */\n    function _addTokenToAllTokensEnumeration(uint256 tokenId) private {\n        _allTokensIndex[tokenId] = _allTokens.length;\n        _allTokens.push(tokenId);\n    }\n\n    /**\n     * @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that\n     * while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for\n     * gas optimizations e.g. when performing a transfer operation (avoiding double writes).\n     * This has O(1) time complexity, but alters the order of the _ownedTokens array.\n     * @param from address representing the previous owner of the given token ID\n     * @param tokenId uint256 ID of the token to be removed from the tokens list of the given address\n     */\n    function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {\n        // To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and\n        // then delete the last slot (swap and pop).\n\n        uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;\n        uint256 tokenIndex = _ownedTokensIndex[tokenId];\n\n        // When the token to delete is the last token, the swap operation is unnecessary\n        if (tokenIndex != lastTokenIndex) {\n            uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];\n\n            _ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token\n            _ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index\n        }\n\n        // This also deletes the contents at the last position of the array\n        delete _ownedTokensIndex[tokenId];\n        delete _ownedTokens[from][lastTokenIndex];\n    }\n\n    /**\n     * @dev Private function to remove a token from this extension's token tracking data structures.\n     * This has O(1) time complexity, but alters the order of the _allTokens array.\n     * @param tokenId uint256 ID of the token to be removed from the tokens list\n     */\n    function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {\n        // To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and\n        // then delete the last slot (swap and pop).\n\n        uint256 lastTokenIndex = _allTokens.length - 1;\n        uint256 tokenIndex = _allTokensIndex[tokenId];\n\n        // When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so\n        // rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding\n        // an 'if' statement (like in _removeTokenFromOwnerEnumeration)\n        uint256 lastTokenId = _allTokens[lastTokenIndex];\n\n        _allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token\n        _allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index\n\n        // This also deletes the contents at the last position of the array\n        delete _allTokensIndex[tokenId];\n        _allTokens.pop();\n    }\n}\n"
      },
      "ERC721.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/ERC721.sol)\n\npragma solidity ^0.8.0;\n\nimport \"IERC721.sol\";\nimport \"IERC721Receiver.sol\";\nimport \"IERC721Metadata.sol\";\nimport \"Address.sol\";\nimport \"Context.sol\";\nimport \"Strings.sol\";\nimport \"ERC165.sol\";\n\n/**\n * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including\n * the Metadata extension, but not including the Enumerable extension, which is available separately as\n * {ERC721Enumerable}.\n */\ncontract ERC721 is Context, ERC165, IERC721, IERC721Metadata {\n    using Address for address;\n    using Strings for uint256;\n\n    // Token name\n    string internal _name;\n\n    // Token symbol\n    string internal _symbol;\n\n    // Mapping from token ID to owner address\n    mapping(uint256 => address) private _owners;\n\n    // Mapping owner address to token count\n    mapping(address => uint256) private _balances;\n\n    // Mapping from token ID to approved address\n    mapping(uint256 => address) private _tokenApprovals;\n\n    // Mapping from owner to operator approvals\n    mapping(address => mapping(address => bool)) private _operatorApprovals;\n\n    /**\n     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.\n     */\n    constructor(string memory name_, string memory symbol_) {\n        _name = name_;\n        _symbol = symbol_;\n    }\n\n    /**\n     * @dev See {IERC165-supportsInterface}.\n     */\n    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {\n        return\n            interfaceId == type(IERC721).interfaceId ||\n            interfaceId == type(IERC721Metadata).interfaceId ||\n            super.supportsInterface(interfaceId);\n    }\n\n    /**\n     * @dev See {IERC721-balanceOf}.\n     */\n    function balanceOf(address owner) public view virtual override returns (uint256) {\n        require(owner != address(0), \"ERC721: balance query for the zero address\");\n        return _balances[owner];\n    }\n\n    /**\n     * @dev See {IERC721-ownerOf}.\n     */\n    function ownerOf(uint256 tokenId) public view virtual override returns (address) {\n        address owner = _owners[tokenId];\n        require(owner != address(0), \"ERC721: owner query for nonexistent token\");\n        return owner;\n    }\n\n    /**\n     * @dev See {IERC721Metadata-name}.\n     */\n    function name() public view virtual override returns (string memory) {\n        return _name;\n    }\n\n    /**\n     * @dev See {IERC721Metadata-symbol}.\n     */\n    function symbol() public view virtual override returns (string memory) {\n        return _symbol;\n    }\n\n    /**\n     * @dev See {IERC721Metadata-tokenURI}.\n     */\n    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {\n        require(_exists(tokenId), \"ERC721Metadata: URI query for nonexistent token\");\n\n        string memory baseURI = _baseURI();\n        return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : \"\";\n    }\n\n    /**\n     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each\n     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty\n     * by default, can be overridden in child contracts.\n     */\n    function _baseURI() internal view virtual returns (string memory) {\n        return \"\";\n    }\n\n    /**\n     * @dev See {IERC721-approve}.\n     */\n    function approve(address to, uint256 tokenId) public virtual override {\n        address owner = ERC721.ownerOf(tokenId);\n        require(to != owner, \"ERC721: approval to current owner\");\n\n        require(\n            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),\n            \"ERC721: approve caller is not owner nor approved for all\"\n        );\n\n        _approve(to, tokenId);\n    }\n\n    /**\n     * @dev See {IERC721-getApproved}.\n     */\n    function getApproved(uint256 tokenId) public view virtual override returns (address) {\n        require(_exists(tokenId), \"ERC721: approved query for nonexistent token\");\n\n        return _tokenApprovals[tokenId];\n    }\n\n    /**\n     * @dev See {IERC721-setApprovalForAll}.\n     */\n    function setApprovalForAll(address operator, bool approved) public virtual override {\n        _setApprovalForAll(_msgSender(), operator, approved);\n    }\n\n    /**\n     * @dev See {IERC721-isApprovedForAll}.\n     */\n    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {\n        return _operatorApprovals[owner][operator];\n    }\n\n    /**\n     * @dev See {IERC721-transferFrom}.\n     */\n    function transferFrom(\n        address from,\n        address to,\n        uint256 tokenId\n    ) public virtual override {\n        //solhint-disable-next-line max-line-length\n        require(_isApprovedOrOwner(_msgSender(), tokenId), \"ERC721: transfer caller is not owner nor approved\");\n\n        _transfer(from, to, tokenId);\n    }\n\n    /**\n     * @dev See {IERC721-safeTransferFrom}.\n     */\n    function safeTransferFrom(\n        address from,\n        address to,\n        uint256 tokenId\n    ) public virtual override {\n        safeTransferFrom(from, to, tokenId, \"\");\n    }\n\n    /**\n     * @dev See {IERC721-safeTransferFrom}.\n     */\n    function safeTransferFrom(\n        address from,\n        address to,\n        uint256 tokenId,\n        bytes memory _data\n    ) public virtual override {\n        require(_isApprovedOrOwner(_msgSender(), tokenId), \"ERC721: transfer caller is not owner nor approved\");\n        _safeTransfer(from, to, tokenId, _data);\n    }\n\n    /**\n     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients\n     * are aware of the ERC721 protocol to prevent tokens from being forever locked.\n     *\n     * `_data` is additional data, it has no specified format and it is sent in call to `to`.\n     *\n     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.\n     * implement alternative mechanisms to perform token transfer, such as signature-based.\n     *\n     * Requirements:\n     *\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must exist and be owned by `from`.\n     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n     *\n     * Emits a {Transfer} event.\n     */\n    function _safeTransfer(\n        address from,\n        address to,\n        uint256 tokenId,\n        bytes memory _data\n    ) internal virtual {\n        _transfer(from, to, tokenId);\n        require(_checkOnERC721Received(from, to, tokenId, _data), \"ERC721: transfer to non ERC721Receiver implementer\");\n    }\n\n    /**\n     * @dev Returns whether `tokenId` exists.\n     *\n     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.\n     *\n     * Tokens start existing when they are minted (`_mint`),\n     * and stop existing when they are burned (`_burn`).\n     */\n    function _exists(uint256 tokenId) internal view virtual returns (bool) {\n        return _owners[tokenId] != address(0);\n    }\n\n    /**\n     * @dev Returns whether `spender` is allowed to manage `tokenId`.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     */\n    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {\n        require(_exists(tokenId), \"ERC721: operator query for nonexistent token\");\n        address owner = ERC721.ownerOf(tokenId);\n        return (spender == owner || isApprovedForAll(owner, spender) || getApproved(tokenId) == spender);\n    }\n\n    /**\n     * @dev Safely mints `tokenId` and transfers it to `to`.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must not exist.\n     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n     *\n     * Emits a {Transfer} event.\n     */\n    function _safeMint(address to, uint256 tokenId) internal virtual {\n        _safeMint(to, tokenId, \"\");\n    }\n\n    /**\n     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is\n     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.\n     */\n    function _safeMint(\n        address to,\n        uint256 tokenId,\n        bytes memory _data\n    ) internal virtual {\n        _mint(to, tokenId);\n        require(\n            _checkOnERC721Received(address(0), to, tokenId, _data),\n            \"ERC721: transfer to non ERC721Receiver implementer\"\n        );\n    }\n\n    /**\n     * @dev Mints `tokenId` and transfers it to `to`.\n     *\n     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible\n     *\n     * Requirements:\n     *\n     * - `tokenId` must not exist.\n     * - `to` cannot be the zero address.\n     *\n     * Emits a {Transfer} event.\n     */\n    function _mint(address to, uint256 tokenId) internal virtual {\n        require(to != address(0), \"ERC721: mint to the zero address\");\n        require(!_exists(tokenId), \"ERC721: token already minted\");\n\n        _beforeTokenTransfer(address(0), to, tokenId);\n\n        _balances[to] += 1;\n        _owners[tokenId] = to;\n\n        emit Transfer(address(0), to, tokenId);\n\n        _afterTokenTransfer(address(0), to, tokenId);\n    }\n\n    /**\n     * @dev Destroys `tokenId`.\n     * The approval is cleared when the token is burned.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     *\n     * Emits a {Transfer} event.\n     */\n    function _burn(uint256 tokenId) internal virtual {\n        address owner = ERC721.ownerOf(tokenId);\n\n        _beforeTokenTransfer(owner, address(0), tokenId);\n\n        // Clear approvals\n        _approve(address(0), tokenId);\n\n        _balances[owner] -= 1;\n        delete _owners[tokenId];\n\n        emit Transfer(owner, address(0), tokenId);\n\n        _afterTokenTransfer(owner, address(0), tokenId);\n    }\n\n    /**\n     * @dev Transfers `tokenId` from `from` to `to`.\n     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.\n     *\n     * Requirements:\n     *\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must be owned by `from`.\n     *\n     * Emits a {Transfer} event.\n     */\n    function _transfer(\n        address from,\n        address to,\n        uint256 tokenId\n    ) internal virtual {\n        require(ERC721.ownerOf(tokenId) == from, \"ERC721: transfer from incorrect owner\");\n        require(to != address(0), \"ERC721: transfer to the zero address\");\n\n        _beforeTokenTransfer(from, to, tokenId);\n\n        // Clear approvals from the previous owner\n        _approve(address(0), tokenId);\n\n        _balances[from] -= 1;\n        _balances[to] += 1;\n        _owners[tokenId] = to;\n\n        emit Transfer(from, to, tokenId);\n\n        _afterTokenTransfer(from, to, tokenId);\n    }\n\n    /**\n     * @dev Approve `to` to operate on `tokenId`\n     *\n     * Emits a {Approval} event.\n     */\n    function _approve(address to, uint256 tokenId) internal virtual {\n        _tokenApprovals[tokenId] = to;\n        emit Approval(ERC721.ownerOf(tokenId), to, tokenId);\n    }\n\n    /**\n     * @dev Approve `operator` to operate on all of `owner` tokens\n     *\n     * Emits a {ApprovalForAll} event.\n     */\n    function _setApprovalForAll(\n        address owner,\n        address operator,\n        bool approved\n    ) internal virtual {\n        require(owner != operator, \"ERC721: approve to caller\");\n        _operatorApprovals[owner][operator] = approved;\n        emit ApprovalForAll(owner, operator, approved);\n    }\n\n    /**\n     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.\n     * The call is not executed if the target address is not a contract.\n     *\n     * @param from address representing the previous owner of the given token ID\n     * @param to target address that will receive the tokens\n     * @param tokenId uint256 ID of the token to be transferred\n     * @param _data bytes optional data to send along with the call\n     * @return bool whether the call correctly returned the expected magic value\n     */\n    function _checkOnERC721Received(\n        address from,\n        address to,\n        uint256 tokenId,\n        bytes memory _data\n    ) private returns (bool) {\n        if (to.isContract()) {\n            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {\n                return retval == IERC721Receiver.onERC721Received.selector;\n            } catch (bytes memory reason) {\n                if (reason.length == 0) {\n                    revert(\"ERC721: transfer to non ERC721Receiver implementer\");\n                } else {\n                    assembly {\n                        revert(add(32, reason), mload(reason))\n                    }\n                }\n            }\n        } else {\n            return true;\n        }\n    }\n\n    /**\n     * @dev Hook that is called before any token transfer. This includes minting\n     * and burning.\n     *\n     * Calling conditions:\n     *\n     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be\n     * transferred to `to`.\n     * - When `from` is zero, `tokenId` will be minted for `to`.\n     * - When `to` is zero, ``from``'s `tokenId` will be burned.\n     * - `from` and `to` are never both zero.\n     *\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n     */\n    function _beforeTokenTransfer(\n        address from,\n        address to,\n        uint256 tokenId\n    ) internal virtual {}\n\n    /**\n     * @dev Hook that is called after any transfer of tokens. This includes\n     * minting and burning.\n     *\n     * Calling conditions:\n     *\n     * - when `from` and `to` are both non-zero.\n     * - `from` and `to` are never both zero.\n     *\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n     */\n    function _afterTokenTransfer(\n        address from,\n        address to,\n        uint256 tokenId\n    ) internal virtual {}\n}\n"
      },
      "IERC721.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721.sol)\n\npragma solidity ^0.8.0;\n\nimport \"IERC165.sol\";\n\n/**\n * @dev Required interface of an ERC721 compliant contract.\n */\ninterface IERC721 is IERC165 {\n    /**\n     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.\n     */\n    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);\n\n    /**\n     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.\n     */\n    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);\n\n    /**\n     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.\n     */\n    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);\n\n    /**\n     * @dev Returns the number of tokens in ``owner``'s account.\n     */\n    function balanceOf(address owner) external view returns (uint256 balance);\n\n    /**\n     * @dev Returns the owner of the `tokenId` token.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     */\n    function ownerOf(uint256 tokenId) external view returns (address owner);\n\n    /**\n     * @dev Safely transfers `tokenId` token from `from` to `to`.\n     *\n     * Requirements:\n     *\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must exist and be owned by `from`.\n     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.\n     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n     *\n     * Emits a {Transfer} event.\n     */\n    function safeTransferFrom(\n        address from,\n        address to,\n        uint256 tokenId,\n        bytes calldata data\n    ) external;\n\n    /**\n     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients\n     * are aware of the ERC721 protocol to prevent tokens from being forever locked.\n     *\n     * Requirements:\n     *\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must exist and be owned by `from`.\n     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.\n     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n     *\n     * Emits a {Transfer} event.\n     */\n    function safeTransferFrom(\n        address from,\n        address to,\n        uint256 tokenId\n    ) external;\n\n    /**\n     * @dev Transfers `tokenId` token from `from` to `to`.\n     *\n     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.\n     *\n     * Requirements:\n     *\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must be owned by `from`.\n     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.\n     *\n     * Emits a {Transfer} event.\n     */\n    function transferFrom(\n        address from,\n        address to,\n        uint256 tokenId\n    ) external;\n\n    /**\n     * @dev Gives permission to `to` to transfer `tokenId` token to another account.\n     * The approval is cleared when the token is transferred.\n     *\n     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.\n     *\n     * Requirements:\n     *\n     * - The caller must own the token or be an approved operator.\n     * - `tokenId` must exist.\n     *\n     * Emits an {Approval} event.\n     */\n    function approve(address to, uint256 tokenId) external;\n\n    /**\n     * @dev Approve or remove `operator` as an operator for the caller.\n     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.\n     *\n     * Requirements:\n     *\n     * - The `operator` cannot be the caller.\n     *\n     * Emits an {ApprovalForAll} event.\n     */\n    function setApprovalForAll(address operator, bool _approved) external;\n\n    /**\n     * @dev Returns the account approved for `tokenId` token.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     */\n    function getApproved(uint256 tokenId) external view returns (address operator);\n\n    /**\n     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.\n     *\n     * See {setApprovalForAll}\n     */\n    function isApprovedForAll(address owner, address operator) external view returns (bool);\n}\n"
      },
      "IERC165.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Interface of the ERC165 standard, as defined in the\n * https://eips.ethereum.org/EIPS/eip-165[EIP].\n *\n * Implementers can declare support of contract interfaces, which can then be\n * queried by others ({ERC165Checker}).\n *\n * For an implementation, see {ERC165}.\n */\ninterface IERC165 {\n    /**\n     * @dev Returns true if this contract implements the interface defined by\n     * `interfaceId`. See the corresponding\n     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]\n     * to learn more about how these ids are created.\n     *\n     * This function call must use less than 30 000 gas.\n     */\n    function supportsInterface(bytes4 interfaceId) external view returns (bool);\n}\n"
      },
      "IERC721Receiver.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @title ERC721 token receiver interface\n * @dev Interface for any contract that wants to support safeTransfers\n * from ERC721 asset contracts.\n */\ninterface IERC721Receiver {\n    /**\n     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}\n     * by `operator` from `from`, this function is called.\n     *\n     * It must return its Solidity selector to confirm the token transfer.\n     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.\n     *\n     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.\n     */\n    function onERC721Received(\n        address operator,\n        address from,\n        uint256 tokenId,\n        bytes calldata data\n    ) external returns (bytes4);\n}\n"
      },
      "IERC721Metadata.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)\n\npragma solidity ^0.8.0;\n\nimport \"IERC721.sol\";\n\n/**\n * @title ERC-721 Non-Fungible Token Standard, optional metadata extension\n * @dev See https://eips.ethereum.org/EIPS/eip-721\n */\ninterface IERC721Metadata is IERC721 {\n    /**\n     * @dev Returns the token collection name.\n     */\n    function name() external view returns (string memory);\n\n    /**\n     * @dev Returns the token collection symbol.\n     */\n    function symbol() external view returns (string memory);\n\n    /**\n     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.\n     */\n    function tokenURI(uint256 tokenId) external view returns (string memory);\n}\n"
      },
      "Address.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)\n\npragma solidity ^0.8.1;\n\n/**\n * @dev Collection of functions related to the address type\n */\nlibrary Address {\n    /**\n     * @dev Returns true if `account` is a contract.\n     *\n     * [IMPORTANT]\n     * ====\n     * It is unsafe to assume that an address for which this function returns\n     * false is an externally-owned account (EOA) and not a contract.\n     *\n     * Among others, `isContract` will return false for the following\n     * types of addresses:\n     *\n     *  - an externally-owned account\n     *  - a contract in construction\n     *  - an address where a contract will be created\n     *  - an address where a contract lived, but was destroyed\n     * ====\n     *\n     * [IMPORTANT]\n     * ====\n     * You shouldn't rely on `isContract` to protect against flash loan attacks!\n     *\n     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets\n     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract\n     * constructor.\n     * ====\n     */\n    function isContract(address account) internal view returns (bool) {\n        // This method relies on extcodesize/address.code.length, which returns 0\n        // for contracts in construction, since the code is only stored at the end\n        // of the constructor execution.\n\n        return account.code.length > 0;\n    }\n\n    /**\n     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to\n     * `recipient`, forwarding all available gas and reverting on errors.\n     *\n     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost\n     * of certain opcodes, possibly making contracts go over the 2300 gas limit\n     * imposed by `transfer`, making them unable to receive funds via\n     * `transfer`. {sendValue} removes this limitation.\n     *\n     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].\n     *\n     * IMPORTANT: because control is transferred to `recipient`, care must be\n     * taken to not create reentrancy vulnerabilities. Consider using\n     * {ReentrancyGuard} or the\n     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].\n     */\n    function sendValue(address payable recipient, uint256 amount) internal {\n        require(address(this).balance >= amount, \"Address: insufficient balance\");\n\n        (bool success, ) = recipient.call{value: amount}(\"\");\n        require(success, \"Address: unable to send value, recipient may have reverted\");\n    }\n\n    /**\n     * @dev Performs a Solidity function call using a low level `call`. A\n     * plain `call` is an unsafe replacement for a function call: use this\n     * function instead.\n     *\n     * If `target` reverts with a revert reason, it is bubbled up by this\n     * function (like regular Solidity function calls).\n     *\n     * Returns the raw returned data. To convert to the expected return value,\n     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].\n     *\n     * Requirements:\n     *\n     * - `target` must be a contract.\n     * - calling `target` with `data` must not revert.\n     *\n     * _Available since v3.1._\n     */\n    function functionCall(address target, bytes memory data) internal returns (bytes memory) {\n        return functionCall(target, data, \"Address: low-level call failed\");\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with\n     * `errorMessage` as a fallback revert reason when `target` reverts.\n     *\n     * _Available since v3.1._\n     */\n    function functionCall(\n        address target,\n        bytes memory data,\n        string memory errorMessage\n    ) internal returns (bytes memory) {\n        return functionCallWithValue(target, data, 0, errorMessage);\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n     * but also transferring `value` wei to `target`.\n     *\n     * Requirements:\n     *\n     * - the calling contract must have an ETH balance of at least `value`.\n     * - the called Solidity function must be `payable`.\n     *\n     * _Available since v3.1._\n     */\n    function functionCallWithValue(\n        address target,\n        bytes memory data,\n        uint256 value\n    ) internal returns (bytes memory) {\n        return functionCallWithValue(target, data, value, \"Address: low-level call with value failed\");\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but\n     * with `errorMessage` as a fallback revert reason when `target` reverts.\n     *\n     * _Available since v3.1._\n     */\n    function functionCallWithValue(\n        address target,\n        bytes memory data,\n        uint256 value,\n        string memory errorMessage\n    ) internal returns (bytes memory) {\n        require(address(this).balance >= value, \"Address: insufficient balance for call\");\n        require(isContract(target), \"Address: call to non-contract\");\n\n        (bool success, bytes memory returndata) = target.call{value: value}(data);\n        return verifyCallResult(success, returndata, errorMessage);\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n     * but performing a static call.\n     *\n     * _Available since v3.3._\n     */\n    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {\n        return functionStaticCall(target, data, \"Address: low-level static call failed\");\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],\n     * but performing a static call.\n     *\n     * _Available since v3.3._\n     */\n    function functionStaticCall(\n        address target,\n        bytes memory data,\n        string memory errorMessage\n    ) internal view returns (bytes memory) {\n        require(isContract(target), \"Address: static call to non-contract\");\n\n        (bool success, bytes memory returndata) = target.staticcall(data);\n        return verifyCallResult(success, returndata, errorMessage);\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n     * but performing a delegate call.\n     *\n     * _Available since v3.4._\n     */\n    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {\n        return functionDelegateCall(target, data, \"Address: low-level delegate call failed\");\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],\n     * but performing a delegate call.\n     *\n     * _Available since v3.4._\n     */\n    function functionDelegateCall(\n        address target,\n        bytes memory data,\n        string memory errorMessage\n    ) internal returns (bytes memory) {\n        require(isContract(target), \"Address: delegate call to non-contract\");\n\n        (bool success, bytes memory returndata) = target.delegatecall(data);\n        return verifyCallResult(success, returndata, errorMessage);\n    }\n\n    /**\n     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the\n     * revert reason using the provided one.\n     *\n     * _Available since v4.3._\n     */\n    function verifyCallResult(\n        bool success,\n        bytes memory returndata,\n        string memory errorMessage\n    ) internal pure returns (bytes memory) {\n        if (success) {\n            return returndata;\n        } else {\n            // Look for revert reason and bubble it up if present\n            if (returndata.length > 0) {\n                // The easiest way to bubble the revert reason is using memory via assembly\n\n                assembly {\n                    let returndata_size := mload(returndata)\n                    revert(add(32, returndata), returndata_size)\n                }\n            } else {\n                revert(errorMessage);\n            }\n        }\n    }\n}\n"
      },
      "Context.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Provides information about the current execution context, including the\n * sender of the transaction and its data. While these are generally available\n * via msg.sender and msg.data, they should not be accessed in such a direct\n * manner, since when dealing with meta-transactions the account sending and\n * paying for execution may not be the actual sender (as far as an application\n * is concerned).\n *\n * This contract is only required for intermediate, library-like contracts.\n */\nabstract contract Context {\n    function _msgSender() internal view virtual returns (address) {\n        return msg.sender;\n    }\n\n    function _msgData() internal view virtual returns (bytes calldata) {\n        return msg.data;\n    }\n}\n"
      },
      "Strings.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev String operations.\n */\nlibrary Strings {\n    bytes16 private constant _HEX_SYMBOLS = \"0123456789abcdef\";\n\n    /**\n     * @dev Converts a `uint256` to its ASCII `string` decimal representation.\n     */\n    function toString(uint256 value) internal pure returns (string memory) {\n        // Inspired by OraclizeAPI's implementation - MIT licence\n        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol\n\n        if (value == 0) {\n            return \"0\";\n        }\n        uint256 temp = value;\n        uint256 digits;\n        while (temp != 0) {\n            digits++;\n            temp /= 10;\n        }\n        bytes memory buffer = new bytes(digits);\n        while (value != 0) {\n            digits -= 1;\n            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));\n            value /= 10;\n        }\n        return string(buffer);\n    }\n\n    /**\n     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.\n     */\n    function toHexString(uint256 value) internal pure returns (string memory) {\n        if (value == 0) {\n            return \"0x00\";\n        }\n        uint256 temp = value;\n        uint256 length = 0;\n        while (temp != 0) {\n            length++;\n            temp >>= 8;\n        }\n        return toHexString(value, length);\n    }\n\n    /**\n     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.\n     */\n    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {\n        bytes memory buffer = new bytes(2 * length + 2);\n        buffer[0] = \"0\";\n        buffer[1] = \"x\";\n        for (uint256 i = 2 * length + 1; i > 1; --i) {\n            buffer[i] = _HEX_SYMBOLS[value & 0xf];\n            value >>= 4;\n        }\n        require(value == 0, \"Strings: hex length insufficient\");\n        return string(buffer);\n    }\n}\n"
      },
      "ERC165.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)\n\npragma solidity ^0.8.0;\n\nimport \"IERC165.sol\";\n\n/**\n * @dev Implementation of the {IERC165} interface.\n *\n * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check\n * for the additional interface id that will be supported. For example:\n *\n * ```solidity\n * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {\n *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);\n * }\n * ```\n *\n * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.\n */\nabstract contract ERC165 is IERC165 {\n    /**\n     * @dev See {IERC165-supportsInterface}.\n     */\n    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {\n        return interfaceId == type(IERC165).interfaceId;\n    }\n}\n"
      },
      "IERC721Enumerable.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/extensions/IERC721Enumerable.sol)\n\npragma solidity ^0.8.0;\n\nimport \"IERC721.sol\";\n\n/**\n * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension\n * @dev See https://eips.ethereum.org/EIPS/eip-721\n */\ninterface IERC721Enumerable is IERC721 {\n    /**\n     * @dev Returns the total amount of tokens stored by the contract.\n     */\n    function totalSupply() external view returns (uint256);\n\n    /**\n     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.\n     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.\n     */\n    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256);\n\n    /**\n     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.\n     * Use along with {totalSupply} to enumerate all tokens.\n     */\n    function tokenByIndex(uint256 index) external view returns (uint256);\n}\n"
      },
      "Ownable.sol": {
        "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)\n\npragma solidity ^0.8.0;\n\nimport \"Context.sol\";\n\n/**\n * @dev Contract module which provides a basic access control mechanism, where\n * there is an account (an owner) that can be granted exclusive access to\n * specific functions.\n *\n * By default, the owner account will be the one that deploys the contract. This\n * can later be changed with {transferOwnership}.\n *\n * This module is used through inheritance. It will make available the modifier\n * `onlyOwner`, which can be applied to your functions to restrict their use to\n * the owner.\n */\nabstract contract Ownable is Context {\n    address internal _owner;\n\n    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);\n\n    /**\n     * @dev Initializes the contract setting the deployer as the initial owner.\n     */\n    constructor() {\n        _transferOwnership(_msgSender());\n    }\n\n    /**\n     * @dev Returns the address of the current owner.\n     */\n    function owner() public view virtual returns (address) {\n        return _owner;\n    }\n\n    /**\n     * @dev Throws if called by any account other than the owner.\n     */\n    modifier onlyOwner() {\n        require(owner() == _msgSender(), \"Ownable: caller is not the owner\");\n        _;\n    }\n\n    /**\n     * @dev Leaves the contract without owner. It will not be possible to call\n     * `onlyOwner` functions anymore. Can only be called by the current owner.\n     *\n     * NOTE: Renouncing ownership will leave the contract without an owner,\n     * thereby removing any functionality that is only available to the owner.\n     */\n    function renounceOwnership() public virtual onlyOwner {\n        _transferOwnership(address(0));\n    }\n\n    /**\n     * @dev Transfers ownership of the contract to a new account (`newOwner`).\n     * Can only be called by the current owner.\n     */\n    function transferOwnership(address newOwner) public virtual onlyOwner {\n        require(newOwner != address(0), \"Ownable: new owner is the zero address\");\n        _transferOwnership(newOwner);\n    }\n\n    /**\n     * @dev Transfers ownership of the contract to a new account (`newOwner`).\n     * Internal function without access restriction.\n     */\n    function _transferOwnership(address newOwner) internal virtual {\n        address oldOwner = _owner;\n        _owner = newOwner;\n        emit OwnershipTransferred(oldOwner, newOwner);\n    }\n}\n"
      },
      "SubJsonParser.sol": {
        "content": "// SPDX-License-Identifier: UNLICENSED\npragma solidity ^0.8.2;\n\ncontract SubJsonParser {\n\n\tfunction generateTokenUriPart1(uint256 _tokenId, uint256 _tier) public pure returns(string memory) {\n\t\treturn string(\n\t\t\tabi.encodePacked(\n\t\t\t\tbytes('data:application/json;utf8,{\"name\":\"'),\n\t\t\t\t_getName(_tokenId, _tier),\n\t\t\t\tbytes('\",\"description\":\"'),\n\t\t\t\t\"NFTBox subscription that guarantees the reception of a monthly box until it expires.\",\n\t\t\t\tbytes('\",\"external_url\":\"'),\n\t\t\t\t_getExternalUrl()\n\t\t\t)\n\t\t);\n\t}\n\n\tfunction generateTokenUriPart2(uint256 _tier, uint256 _counter, uint256 _start, uint256 _length) public pure returns(string memory) {\n\t\treturn string(\n\t\t\tabi.encodePacked(\n\t\t\t\tbytes('\",\"attributes\":['),\n\t\t\t\t_tierSub(_tier),\n\t\t\t\t_expiry(_length <= (_counter - _start) ? 0 : (_length - (_counter - _start))),\n\t\t\t\tbytes(',\"image\":\"'),\n\t\t\t\t_getImageCache(_tier),\n\t\t\t\tbytes('\"}')\n\t\t\t)\n\t\t);\n\t}\n\n\tfunction _getImageCache(uint256 _tier) internal pure returns(string memory) {\n\t\tif (_tier == 3)\n\t\t\treturn string(abi.encodePacked(\"https://ipfs.io/ipfs/QmV3GaTzqLvGSRTAuiLQGsBUDDx4Dr7G7gxqtR8eRhudLL\"));\n\t\tif (_tier == 6)\n\t\t\treturn string(abi.encodePacked(\"https://ipfs.io/ipfs/QmZBtFNpbrstaKwSDzsB3uFGMeN7b5VjT93Udab2EbB2tQ\"));\n\t\tif (_tier == 9)\n\t\t\treturn string(abi.encodePacked(\"https://ipfs.io/ipfs/QmPCv1DEWH6pTXXVVdR3nqcavT1bzNRY5QoyR6KEzVjUkb\"));\n\t\treturn string(abi.encodePacked(\"\"));\n\t}\n\n\tfunction _getName(uint256 _tokenId, uint256 _tier) internal pure returns(string memory) {\n\t\treturn string(abi.encodePacked(\"NFTBox \", _tierName(_tier), \" Subscription\"));\n\t}\n\n\tfunction _tierSub(uint256 _tier) internal pure returns(string memory) {\n\t\treturn string(abi.encodePacked(bytes('{\"trait_type\": \"Tier\",\"value\":\"'), _tierName(_tier), bytes('\"},')));\n\t}\n\n\tfunction _tierName(uint256 _tier) internal pure returns(string memory) {\n\t\tif (_tier == 0)\n\t\t\treturn string(abi.encodePacked(\"Bronze\"));\n\t\tif (_tier == 1)\n\t\t\treturn string(abi.encodePacked(\"Silver\"));\n\t\tif (_tier == 2)\n\t\t\treturn string(abi.encodePacked(\"Gold\"));\n\t\tif (_tier == 3)\n\t\t\treturn string(abi.encodePacked(\"Bronze\"));\n\t\tif (_tier == 6)\n\t\t\treturn string(abi.encodePacked(\"Silver\"));\n\t\tif (_tier == 9)\n\t\t\treturn string(abi.encodePacked(\"Gold\"));\n\t}\n\n\tfunction _expiry(uint256 _expirationCount) internal pure returns(string memory) {\n\t\treturn string(abi.encodePacked(bytes('{\"trait_type\": \"Boxes left\",\"value\":\"'), _uint2str(_expirationCount), bytes('\"}]')));\n\t}\n\n\tfunction _getImageCache(string memory _hash) internal pure returns(string memory) {\n\t\treturn string(abi.encodePacked(\"https://ipfs.io/ipfs/\", _hash));\n\t}\n\n\tfunction _getExternalUrl() internal pure returns(string memory) {\n\t\treturn string(abi.encodePacked(\"https://www.nftboxes.io/\"));\n\t}\n\n\tfunction _uint2str(uint _i) internal pure returns (string memory _uintAsString) {\n\t\tif (_i == 0) {\n\t\t\treturn \"0\";\n\t\t}\n\t\tuint j = _i;\n\t\tuint len;\n\t\twhile (j != 0) {\n\t\t\tlen++;\n\t\t\tj /= 10;\n\t\t}\n\t\tbytes memory bstr = new bytes(len);\n\t\tuint k = len;\n\t\twhile (_i != 0) {\n\t\t\tk = k-1;\n\t\t\tuint8 temp = (48 + uint8(_i - _i / 10 * 10));\n\t\t\tbytes1 b1 = bytes1(temp);\n\t\t\tbstr[k] = b1;\n\t\t\t_i /= 10;\n\t\t}\n\t\treturn string(bstr);\n\t}\n}"
      }
    },
    "settings": {
      "evmVersion": "istanbul",
      "optimizer": {
        "enabled": true,
        "runs": 200
      },
      "libraries": {
        "SubscriptionService.sol": {}
      },
      "outputSelection": {
        "*": {
          "*": [
            "evm.bytecode",
            "evm.deployedBytecode",
            "devdoc",
            "userdoc",
            "metadata",
            "abi"
          ]
        }
      }
    }
  }}