VNFT.sol

// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity >=0.8.0;

import "openzeppelin-contracts/contracts/token/ERC721/ERC721.sol";
import "openzeppelin-contracts/contracts/access/Ownable.sol";
import "openzeppelin-contracts/contracts/utils/Strings.sol";
import "openzeppelin-contracts/contracts/utils/cryptography/ECDSA.sol";

contract VNFT is ERC721, Ownable {
    uint256 public constant MAX_SUPPLY = 10000;
    uint256 public constant MAX_TX = 2;
    uint256 public constant MAX_WALLET = 2;

    uint256 public totalSupply;
    mapping(address => uint256) public mintsPerWallet;
    string public baseURI;

    constructor() ERC721("VulnerableNFT", "VNFT") {}

    function withdraw() external onlyOwner {
        uint256 balance = address(this).balance;
        payable(msg.sender).transfer(balance);
    }

    function setBaseURI(string memory _baseURI) external onlyOwner {
        baseURI = _baseURI;
    }

    // try your luck and mint even if you are not whitelisted
    function imFeelingLucky(address to, uint256 qty, uint256 number) external {
        require(qty > 0 && qty <= MAX_TX, "Invalid quantity");
        require(totalSupply + qty <= MAX_SUPPLY, "Max supply reached");
        require(mintsPerWallet[to] + qty <= MAX_WALLET, "Max balance per wallet reached");
        require((msg.sender).code.length == 0, "Only EOA allowed");

        uint256 randomNumber =
            uint256(keccak256(abi.encodePacked(blockhash(block.number - 1), block.timestamp, totalSupply))) % 100;

        require(randomNumber == number, "Better luck next time!");

        unchecked {
            mintsPerWallet[to] += qty;
            uint256 mintId = totalSupply;
            totalSupply += qty;
            for (uint256 i = 0; i < qty; i++) {
                _safeMint(to, mintId++);
            }
        }
    }

    // only whitelisted wallets can mint
    function whitelistMint(address to, uint256 qty, bytes32 hash, bytes memory signature) external payable {
        require(recoverSigner(hash, signature) == owner(), "Address is not allowlisted");
        require(totalSupply + qty <= MAX_SUPPLY, "Max supply reached");
        require(mintsPerWallet[to] + qty <= MAX_WALLET, "Max balance per wallet reached");

        unchecked {
            mintsPerWallet[to] += qty;
            uint256 mintId = totalSupply;
            totalSupply += qty;
            for (uint256 i = 0; i < qty; i++) {
                _safeMint(to, mintId++);
            }
        }
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 _tokenId) public view override returns (string memory) {
        require(_tokenId < totalSupply, "Non existent token");
        return string(abi.encodePacked(baseURI, Strings.toString(_tokenId)));
    }

    function recoverSigner(bytes32 hash, bytes memory signature) public pure returns (address) {
        bytes32 messageDigest = keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
        return ECDSA.recover(messageDigest, signature);
    }
}