Estos son los NFTs más Justos

Podemos lanzar NFTs de maneras más justas y divertidas combinando whitelists con eventos de comunidad y gamification. En este video exploramos una implementación de whitelist en un contrato de NFTs y también otras ideas que Vitalik ha planteado en su blog para ofrecer una mejor experiencia a los participantes.

https://youtu.be/pu_tp4d8ii0

Antes de comenzar

Para este tutorial ocuparás Metamask u otra wallet compatible con fondos en Goerli que puedes obtener desde un faucet.

El Smart Contract

// SPDX-License-Identifier: MIT
pragma solidity 0.8.16;

import '@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol';
import '@openzeppelin/contracts/access/Ownable.sol';

contract MyWhitelistNFT is ERC721Enumerable, Ownable {  
    uint256 public price = 0.01 ether;
    uint256 public constant MAX_SUPPLY = 10000;
    string public baseTokenURI = "https://baseurl.com/";

    bool public saleActive = false;
    mapping (address => uint256) public whitelistReserved;

    constructor () ERC721 ("My MNFT", "MNFT") {
    }

    // Overide functions

    function _baseURI() internal view virtual override returns (string memory) {
        return baseTokenURI;
    }

    // Public functions

    function mintToken(uint256 _amount) public payable {
        uint256 supply = totalSupply();
        require( supply + _amount <= MAX_SUPPLY, "Can't mint more than max supply" );
        require( msg.value == price * _amount, "Wrong amount of ETH sent" );

        if(!saleActive)
        {
            uint256 reservedAmt = whitelistReserved[msg.sender];
            require(reservedAmt > 0 && _amount <= reservedAmt, "Sale isn't active and you are not whitelisted" );
            whitelistReserved[msg.sender] = reservedAmt - _amount;
        }

        for(uint256 i; i < _amount; i++){
            _safeMint( msg.sender, supply + i );
        }
    }

    // Admin functions

    function editWhitelistReserved(address[] memory _a, uint256[] memory _amount) public onlyOwner {
        for(uint256 i; i < _a.length; i++){
            whitelistReserved[_a[i]] = _amount[i];
        }
    }

    function setSaleActive(bool val) public onlyOwner {
        saleActive = val;
    }

    function setBaseURI(string memory baseURI) public onlyOwner {
        baseTokenURI = baseURI;
    }

    function withdraw() public payable onlyOwner {
        (bool sent, bytes memory data) = owner().call{value: address(this).balance}("");
        data;
        require(sent, "Failed to send Ether");
    }
}