NftRunners.sol

//SPDX-License-Identifier: MIT
pragma solidity 0.8.13;
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import "@openzeppelin/contracts/utils/Counters.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/utils/Base64.sol";
import "@chainlink/contracts/src/v0.8/interfaces/VRFCoordinatorV2Interface.sol";
import "@chainlink/contracts/src/v0.8/VRFConsumerBaseV2.sol";
contract NftRunners is ERC721, ERC721URIStorage, VRFConsumerBaseV2 {
    using Counters for Counters.Counter;
    using Strings for uint256;
    //VRF
    VRFCoordinatorV2Interface COORDINATOR;
    // Mumbai coordinator
    address vrfCoordinator = 0x7a1BaC17Ccc5b313516C5E16fb24f7659aA5ebed;
    bytes32 keyHash = 0x4b09e658ed251bcafeebbc69400383d49f344ace09b9576fe248bb02c003fe9f;
    uint32 callbackGasLimit = 2500000;
    uint16 requestConfirmations = 3;
    uint32 numWords =  1;
    uint64 public s_subscriptionId;
    uint256[] public s_randomWords;
    uint256 public s_requestId;
    address s_owner;
    //NFT
    Counters.Counter public tokenIdCounter;
    string[] characters = [
        "https://ipfs.io/ipfs/QmTgqnhFBMkfT9s8PHKcdXBn1f5bG3Q5hmBaR4U6hoTvb1?filename=Chainlink_Elf.png",
        "https://ipfs.io/ipfs/QmZGQA92ri1jfzSu61JRaNQXYg1bLuM7p8YT83DzFA2KLH?filename=Chainlink_Knight.png",
        "https://ipfs.io/ipfs/QmW1toapYs7M29rzLXTENn3pbvwe8ioikX1PwzACzjfdHP?filename=Chainlink_Orc.png",
        "https://ipfs.io/ipfs/QmPMwQtFpEdKrUjpQJfoTeZS1aVSeuJT6Mof7uV29AcUpF?filename=Chainlink_Witch.png"
    ];
    struct Runner {
        string image;
        uint256 distance;
    }
    Runner[] public runners;
    constructor(uint64 subscriptionId) ERC721("RunnerNFT", "RUN") VRFConsumerBaseV2(vrfCoordinator) {
        COORDINATOR = VRFCoordinatorV2Interface(vrfCoordinator);
        s_owner = msg.sender;
        s_subscriptionId = subscriptionId;
        safeMint(msg.sender,3);
    }
    function safeMint(address to, uint256 charId) public {
        uint8 aux = uint8 (charId);
        require( (aux >= 0) && (aux <= 3), "invalid charId");
        string memory yourCharacterImage = characters[charId];
        runners.push(Runner(yourCharacterImage,0));
        uint256 tokenId = tokenIdCounter.current();
        string memory uri = Base64.encode(
            bytes(
                string(
                    abi.encodePacked(
                        '{"name": "RunnerNFT",',
                        '"description": "This is your character",',
                        '"image": "', runners[tokenId].image, '",'
                        '"attributes": [',
                        '{',
                            '"trait_type": "distance",',
                            '"value": ', runners[tokenId].distance.toString(),
                            '}]'
                        '}'
                    )
                )
            )
        );
        // Create token URI
        string memory finalTokenURI = string(
            abi.encodePacked("data:application/json;base64,", uri)
        );
        tokenIdCounter.increment();
        _safeMint(to, tokenId);
        _setTokenURI(tokenId, finalTokenURI);
    }
    function run() public {
        s_requestId = COORDINATOR.requestRandomWords(
            keyHash,
            s_subscriptionId,
            requestConfirmations,
            callbackGasLimit,
            numWords
        );
    }
    function fulfillRandomWords(
        uint256, /* requestId */
        uint256[] memory randomWords
    ) internal override {
        require (tokenIdCounter.current() >= 0, "You must mint a NFT");
        s_randomWords = randomWords;
        uint aux = (s_randomWords[0] % 10 + 1) * 10;
        uint256 tokenId = tokenIdCounter.current()-1;
        runners[tokenId].distance += aux;
        string memory uri = Base64.encode(
            bytes(
                string(
                    abi.encodePacked(
                        '{"name": "RunnerNFT",',
                        '"description": "This is your character",',
                        '"image": "', runners[tokenId].image, '",'
                        '"attributes": [',
                        '{',
                            '"trait_type": "distance",',
                            '"value": ', runners[tokenId].distance.toString(),
                            '}]'
                        '}'
                    )
                )
            )
        );
        // Create token URI
        string memory finalTokenURI = string(
            abi.encodePacked("data:application/json;base64,", uri)
        );
        _setTokenURI(tokenId, finalTokenURI);
    }
   
    // The following functions are overrides required by Solidity.
    function _burn(uint256 tokenId) internal override(ERC721, ERC721URIStorage) {
        super._burn(tokenId);
    }
    function tokenURI(uint256 tokenId)
        public
        view
        override(ERC721, ERC721URIStorage)
        returns (string memory)
    {
        return super.tokenURI(tokenId);
    }
}