Hashlips contract modified to work with merkle tree

NFT_PRESALE_MERKLETREE.sol

// SPDX-License-Identifier: GPL-3.0
//  #     #                                   #
//  #     # #    #  ####  #      ######      # #     ##   #####   ####  #    #
//  #     # ##   # #    # #      #          #   #   #  #  #    # #    # #    #
//  #     # # #  # #      #      #####     #     # #    # #    # #    # ######
//  #     # #  # # #      #      #         ####### ###### #####  #    # #    #
//  #     # #   ## #    # #      #         #     # #    # #   #  #    # #    #
//   #####  #    #  ####  ###### ######    #     # #    # #    #  ####  #    #

// Amended by HashLips, improved by Uncle Aaroh !
/**
    !Disclaimer!
    These contracts have been used to create tutorials,
    and was created for the purpose to teach people
    how to create smart contracts on the blockchain.
    please review this code on your own before using any of
    the following code for production.
    HashLips will not be liable in any way if for the use 
    of the code. That being said, the code has been tested 
    to the best of the developers' knowledge to work as intended.
*/

pragma solidity >=0.7.0 <0.9.0;

import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";

contract NFT is ERC721Enumerable, Ownable {
    using Strings for uint256;
    string public baseURI;
    string public baseExtension = ".json";
    string public notRevealedUri;
    uint256 public cost = 1 ether;
    uint256 public whiteListCost = 0.5 ether;
    uint256 public maxSupply = 10000;
    uint256 public maxMintAmount = 20;
    uint256 public nftPerAddressLimit = 3;
    bool public paused = false;
    bool public revealed = false;

    mapping(address => uint256) public addressMintedBalance;

    //////// Uncle Aaroh Addition ///////
    //// Merkle Tree Root Address  - Gas Optimisation
    bytes32 public whitelistMerkleRoot;

    //////////////////

    constructor(
        string memory _name,
        string memory _symbol,
        string memory _initBaseURI,
        string memory _initNotRevealedUri
    ) ERC721(_name, _symbol) {
        setBaseURI(_initBaseURI);
        setNotRevealedURI(_initNotRevealedUri);
    }

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

    // public
    function mint(uint256 _mintAmount) public payable {
        require(!paused, "the contract is paused");
        uint256 supply = totalSupply();
        require(_mintAmount > 0, "need to mint at least 1 NFT");
        require(
            _mintAmount <= maxMintAmount,
            "max mint amount per session exceeded"
        );
        require(supply + _mintAmount <= maxSupply, "max NFT limit exceeded");

        if (msg.sender != owner()) {
            require(msg.value >= cost * _mintAmount, "insufficient funds");
        }

        for (uint256 i = 1; i <= _mintAmount; i++) {
            addressMintedBalance[msg.sender]++;
            _safeMint(msg.sender, supply + i);
        }
    }

    //////// Uncle Aaroh Addition ///////
    modifier isValidMerkleProof(bytes32[] calldata merkleProof, bytes32 root) {
        require(
            MerkleProof.verify(
                merkleProof,
                root,
                keccak256(abi.encodePacked(msg.sender))
            ),
            "Address does not exist in list"
        );
        _;
    }

    modifier isCorrectPayment(uint256 price, uint256 numberOfTokens) {
        require(
            price * numberOfTokens == msg.value,
            "Incorrect ETH value sent"
        );
        _;
    }

    function mintWhitelist(bytes32[] calldata merkleProof)
        public
        payable
        isValidMerkleProof(merkleProof, whitelistMerkleRoot)
        isCorrectPayment(whiteListCost, 1)
    {
        uint256 supply = totalSupply();
        require(supply + 1 <= maxSupply, "max NFT limit exceeded");
        _safeMint(msg.sender, supply + 1);
    }

    function setWhitelistMerkleRoot(bytes32 merkleRoot) external onlyOwner {
        whitelistMerkleRoot = merkleRoot;
    }

    //////////////////////////////////////

    function walletOfOwner(address _owner)
        public
        view
        returns (uint256[] memory)
    {
        uint256 ownerTokenCount = balanceOf(_owner);
        uint256[] memory tokenIds = new uint256[](ownerTokenCount);
        for (uint256 i; i < ownerTokenCount; i++) {
            tokenIds[i] = tokenOfOwnerByIndex(_owner, i);
        }
        return tokenIds;
    }

    function tokenURI(uint256 tokenId)
        public
        view
        virtual
        override
        returns (string memory)
    {
        require(
            _exists(tokenId),
            "ERC721Metadata: URI query for nonexistent token"
        );

        if (revealed == false) {
            return notRevealedUri;
        }

        string memory currentBaseURI = _baseURI();
        return
            bytes(currentBaseURI).length > 0
                ? string(
                    abi.encodePacked(
                        currentBaseURI,
                        tokenId.toString(),
                        baseExtension
                    )
                )
                : "";
    }

    //only owner
    function reveal() public onlyOwner {
        revealed = true;
    }

    function setNftPerAddressLimit(uint256 _limit) public onlyOwner {
        nftPerAddressLimit = _limit;
    }

    function setCost(uint256 _newCost) public onlyOwner {
        cost = _newCost;
    }

    function setWhitelistCost(uint256 _newCost) public onlyOwner {
        whiteListCost = _newCost;
    }

    function setmaxMintAmount(uint256 _newmaxMintAmount) public onlyOwner {
        maxMintAmount = _newmaxMintAmount;
    }

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

    function setBaseExtension(string memory _newBaseExtension)
        public
        onlyOwner
    {
        baseExtension = _newBaseExtension;
    }

    function setNotRevealedURI(string memory _notRevealedURI) public onlyOwner {
        notRevealedUri = _notRevealedURI;
    }

    function pause(bool _state) public onlyOwner {
        paused = _state;
    }

    function withdraw() public payable onlyOwner {
        (bool os, ) = payable(owner()).call{value: address(this).balance}("");
        require(os);
    }
}

Great work! Very useful code thank you very much for the doing this! Since Hashlips's original contract is MIT licensed, could you change the license to MIT? I want to save money on minting fees, but I don't want my entire dapp to have to switch to a GPL license.

Great work! Very useful code thank you very much for the doing this! Since Hashlips's original contract is MIT licensed, could you change the license to MIT? I want to save money on minting fees, but I don't want my entire dapp to have to switch to a GPL license.

Hi @ChristianOConnor, take inspiration, don't copy 👍