contract TheSignature is ERC721 {

    address public owner = 0x0CaCC6104D8Cd9d7b2850b4f35c65C1eCDEECe03; // for opensea integration. doesn't do anything else.

    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    constructor (string memory name_, string memory symbol_) ERC721(name_, symbol_) {
        _mintSignature(owner);
    }

    /**
     * @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 name = "The Signature"; 
        string memory description = "A conceptual art project that emphasises the provenance of an NFT. All pieces look the same. Anyone can mint a piece at any time (only pay gas). No restrictions. Uncapped supply. The only way they differ is when it was minted and by whom. Over time, if transferred, a piece will attract more signatures from more holders.";

        string memory image = generateBase64Image();
        return string(
            abi.encodePacked(
                'data:application/json;base64,',
                Base64.encode(
                    bytes(
                        abi.encodePacked(
                            '{"name":"', 
                            name,
                            '", "description":"', 
                            description,
                            '", "image": "', 
                            'data:image/svg+xml;base64,', 
                            image,
                            '"}'
                        )
                    )
                )
            )
        );
    }

    function generateBase64Image() public pure returns (string memory) {
        bytes memory img = bytes(generateImage());
        return Base64.encode(img);
    }

    function generateImage() public pure returns (string memory) {
        return string(
            abi.encodePacked(
                '<svg xmlns="http://www.w3.org/2000/svg" width="1493.338" height="1493.338" viewBox="0 0 1400 1400"><path stroke="#000" d="M616 933c-5.84-2.04-18.74 2.17-26 1.79-17.08-.88-36.78-6.12-53-11.62-10.97-3.72-23.77-10.08-32.72-17.46-8.87-7.33-23.1-22.32-28.02-32.71-9.92-20.91 1.82-41.48 17.74-55.27 4.92-4.27 9.61-8.81 15-12.51 20.47-14.08 59.06-27.78 84.01-28.65l25.99.6 7.71 1.35 22.29 1.67c6.36.23 16.59-2.28 16-10.19l-9 2.75c-12.41 2.25-26.61-1.98-38.83-2.53-26.58-1.22-47.1.46-72.17 10.33-7.88 3.1-25.43 8.66-30 15.45-6.3.62-14.97 7.71-20 11.67-5.93 4.67-16.99 16.02-21.03 22.42-1.29 2.05-3.12 6.53-4.07 8.91-4.61 11.53-6.22 22.16-1.27 34 6.53 15.64 26.98 36.73 41.37 45.54 9.75 5.96 28.77 13.66 39.91 16.59l10.66 1.87 5.02 1.57c8.68 2.09 25.46 3.83 34.45 3.11l7.96-1.5c8.37-1.1 22.2-3.49 30.09-6.08l7.91-3.35 11-4.3c26.73-12.54 57.13-35.24 75.33-58.45 11.83-15.07 17.15-28.37 23.72-46 3.39-9.11 6.89-18.45 8.85-28l1.18-10 2.75-17c2.05-19.62-1.05-46.32-7.44-65-3.02-8.83-13.92-27.46-19.63-35-24.7-32.65-58.61-47.31-95.76-60.95-16.45-6.03-35.01-9.5-45.33-25.05-2.56-3.86-3.75-7.67-5.12-12-1.43-4.5-2.1-6.07-2.21-11-.22-9.58 3.95-23.49 8.29-32 14.85-29.17 42.97-47.03 74.46-53.57l8.91-2.27 35.46-4.36c4.39.19 14.55 3.38 17.25 2.01 1.5-.76 1.57-1.57 2.29-2.81-2.52-1.82-4.99-3.9-7.96-4.74-4.25-1.64-25.15-.66-30.13 0l-7.91 1.83c-4.05.41-8.05.58-12 1.69l-6 1.85-7 1.13c-7.88 2.03-15.73 5.7-23 9.28l-10 4.84c-18.4 10.68-32.96 26.41-41.14 46.12-4.51 10.87-9.26 25.09-6.83 37 1.53 7.48 7.65 21.61 13.07 26.87 11.83 11.47 38.31 18.68 53.9 24.86 14.74 5.84 43.19 18.88 55.08 28.41l5.09 4.85 13.75 12.14c6.53 6.24 11.33 14.09 15.78 21.87 14.15 24.76 17.39 43.85 17.58 72 .08 11.31-.74 8.4-1.99 18l-.72 9-5.1 23c-3.19 12.43-12.08 35.45-19.01 45.99l-12.14 16.84c-4.34 5.06-21.72 21.18-27.32 25.71-11.97 9.68-33.67 23.46-48 28.93l-19 6.16c-4.07 1.03-9.7 1.81-13 4.37ZM284 662l20-16.32c14.33-9.74 19.82-11.02 35-17.72l8-3.87c29.18-11.85 59.67-21.5 89.73-30.85l18.31-5.12 5.96-2.45 42.01-11.83c18.65-7.65 34.8-11.64 52.99-21.7 3.47-1.92 15.76-10.27 10.25-15.22-4.26-3.82-5.5 3.34-14.25 8.38-11.61 6.7-24.35 11.45-37 15.84l-13 4.16-56 16.44-35.72 12.24-16.28 4.76-31 11.37-20 7.35-13 6.12c-4.9 2.1-19.94 9.41-23.83 12.14L294 645.58c-5.58 4.36-11.78 8.53-10 16.42Zm144 57c5.47-5.53 7.23-16.62 9.59-24 6.75-21.15 13.97-54.96 12.96-77 .08-3.24.79-11.35 0-13.92-1.61-3.75-5.97-4.49-6.62 0V613c.11 24.25-5.11 48.36-10.05 72-1.93 9.24-8.08 25.12-5.88 34Zm44-45c-5.14 5.38-11.14 10.7-13.7 18-1.32 3.76.06 8.17 4.7 7.12 5.81-1.32 12.74-13.01 18-17.12 1.9 2.35 2.02 2.09 5 2 2.24 3.26 10.15 5.89 14 7.99 15.71 8.57 21.41 16.58 41 12.68 14.97-2.99 27.88-16.69 19-31.67-5.66 6.23-2.59 10.36-6.7 15.89-2.09 2.81-4 3.28-6.88 4.78-9.65 5.06-16.84 4.07-27.42 3.33 6.31-7.89 11.41-11.95 12.52-23 .74-7.38-4.67-11.93-11.52-8.07-4.03 2.28-7.68 7.09-9.96 11.07-1.07 1.87-2.77 6.13-4.45 7.19-2.25 1.41-4.5-.14-6.59-1.02-3.85-1.63-14.44-3.51-13.99-9.26.2-2.59 6.85-13.87 8.39-16.91l10.99-28c.98-3.34 4.56-13.7 0-15.83-5.49-2.77-7.48 10.72-8.21 13.83l-7.7 22-7.07 13c-2.19 4.24-4.53 10.51-9.41 12Zm53-2c-1.72 7.36-3.66 14.79-11 18 .19-7.77 2.89-15.6 11-18Zm-18 14v1l-1-1h1Zm472 31-1 9-21-1.74c-3.42-.78-9.67-2.67-12.79-.57-2.53 1.7-4.93 6.42-.56 7.82l7.63.63c11.25 1.93 13.87 2.86 25.72 2.86-6.37 12.58-10.45 34.17-25 40 .44-3.63 1.37-7.88-2.22-10.59-1.06-.48-2.25-.81-3.47 0-2.95 1.14-1.84 5.9-2.91 8.4-2.65 6.21-9.51 4.96-14.4 3.19 1.88-3.85 2.82-8.4 6.62-10.87 4.82-3.12 11.46-2.47 11.84-7.14.41-5.01-6.5-4.1-9.46-3.19-7.2 2.22-11.3 7.07-13 14.2-10.17-3.99-13.92-16.31-24-15.11-6.44.77-11.85 10.66-13.9 16.11-1.39 2.81-2.46 6.21 0 8.58 2.89 2.35 5.56.49 7.51-1.69 3.44-3.87 6.09-10.8 5.39-15.89 7.79 2.02 9.26 5.85 15 10.79l6.7 5.41c2.28 2.26 3.51 4.57 6.47 6.22 7.11 3.93 13.51-1.05 16.7-2 3.44-.97 5.28.78 8.64 0 5.27-1.3 9.82-6.71 13.49-10.42.07 7.58 1.69 14.27 7.62 19.57 6.57 5.88 16.66 3.1 20.38-4.57 4.1 3.44 7.83 5.63 13 2.4 2.07-1.29 4.54-4.27 6.58-4.78 2.14-.54 4.16 1.57 7.7.8 3.21-.71 9.69-5.46 12.72-7.42-1.76 4.08-3.8 7.74 2 9 1.96 4.53 4.7.79 6.16-2.02 2.38-4.56 2.94-11.03 1.84-15.98 4.37.89 10.61 3.65 12.4 8.09 1.15 2.85-.14 6.05 2.34 9.89 3.42 5.29 11.34 7.14 17.26 7.38 6.92.28 26.57-5.43 32.99-8.54 5.33-2.59 10.3-7.96 3.01-11.82-4.37 7.03-11.47 7.89-19 9.88-9.78 2.6-22.44 8.62-29-2.88 7.68 1.25 10.19 3.22 17.99-.75 6.93-3.53 13.82-14.3 13.73-22.25-.03-2.76-1-4.83-2.95-6.58-5.11-5.3-10.5-2.99-15.77 0-3.7 2.43-6.29 4.28-9.33 7.38-4.37 4.45-5.37 6.57-7.67 12.2h-2c-1.05-2.23-1.41-3.06-3.14-4.96-.96-1.07-2.67-2.63-3.86-3.43-8.29-5.55-14.25 4.99-17.45 7.91-3.24 2.95-10.19 6.67-14.62 7.48v-7.58c.12-3.98 1.68-7.68.92-12.4-.71-4.5-4.03-5.45-6.09-3.4-2.38 2.37-1.11 8.5-2.03 12.38-1.71 7.22-4.94 12.46-9.73 18l2.42-9.83V757l-3.42-5c-10.44 8.22-4.17 24.51-12.3 31.68-3.12 2.75-10.01 2.95-12.39-.92-.95-1.55-1.46-4.91-1.71-6.76-1.77-13.24 6.44-30.68 7.4-40l20 1c3.58-.02 9.17-.18 10.83-4.17 1.32-3.18-2.18-5.37-4.83-5.86h-23c1.58-2.85 3.79-8.64 3.67-11.95-.2-5.39-4.11-4.36-7.09-1.67L979 717Zm-163 24c-.98-1.13-1.57-2.22-3.02-2.83-4.86-1.93-4.73 5.66 0 4.52 1.38-.32 2.04-1.07 3.02-1.69Zm36 19c1.66 4.55 2.6 11.14 2.6 16v5l1.08 5v5l2.48 8.42 3.42 31.58c.34 6.2-.68 12.86-1.4 19-.4 3.33-.23 6.1-1.27 9.42-1.66 5.34-4.35 14.4-8.08 18.37-3.81 4.05-8.52 1.32-9.83 7.21-8.06.35-12.27-4.23-17.27-10-9.12-10.53-14.77-22.45-20.52-35-3.58-7.89-7.56-15.67 0-22.73 7.09-6.67 25.07-11.19 34.79-13.1 7.38-1.45 12.83 1.14 17-7.17-13.04-3.25-36.01 3.15-48 8.63-6.54 2.99-12.55 7.22-14.98 14.37-3.19 9.36 1.83 18.1 6.08 26l3.59 8c5.05 10.78 9.42 18.06 17.48 27 4.45 4.93 10.04 10.17 16.83 11.43 14.41 2.68 27-13.8 29.3-26.34l3.34-13.09v-41.72L865.66 792l-1.89-7.59L861.1 765c-.39-2.94-1.74-9.52-3.68-11.68-2.68-2.98-6.94-1.38-10.42-1.27-9.88.29-20.46 6.1-26.47 13.95-2.5 3.27-5.15 7.86-2.64 11.87 2.77 4.39 8.8 4.73 13.11 2.69 6.4-3.03 17.74-14.28 21-20.56Zm-50-7c-3.71 5.44-6.62 14.35-6.9 21-.09 2.1-.11 6.8 2.99 6.8 3.08 0 4.34-4.47 4.89-6.8 1.57-6.58 4.3-15.65-.98-21Zm288 2c-1.72 12.97-9.11 21.95-23 18 3.71-9.38 11.79-20.18 23-18Zm-244 3c-5.41 8.52-11.63 16.12-22 18 .83-10.32 12.71-16.54 22-18Z"/></svg>'
            )
        );
    }

    function mintSignature() public {
        _mintSignature(msg.sender);
    }

    function _mintSignature(address _owner) internal {
        uint256 tokenId = uint(keccak256(abi.encodePacked(block.timestamp, _owner)));
        super._mint(_owner, tokenId);
    }
}
/**
 * @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}.
 */
function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");

        string memory name = "The Signature"; 
        string memory description = "A conceptual art project that emphasises the provenance of an NFT. All pieces look the same. Anyone can mint a piece at any time (only pay gas). No restrictions. Uncapped supply. The only way they differ is when it was minted and by whom. Over time, if transferred, a piece will attract more signatures from more holders.";

        string memory image = generateBase64Image();
        return string(
            abi.encodePacked(
                'data:application/json;base64,',
                Base64.encode(
                    bytes(
                        abi.encodePacked(
                            '{"name":"', 
                            name,
                            '", "description":"', 
                            description,
                            '", "image": "', 
                            'data:image/svg+xml;base64,', 
                            image,
                            '"}'
                        )
                    )
                )
            )
        );
    }
/**
 * @dev See {IERC721Metadata-tokenURI}.
 */