contract LdcNFT is ERC721Enumerable, Ownable {
  using Strings for uint256;

  string public baseURI;
  string public baseExtension = ".json";
  uint256 public cost = 20000000000000000; // 0.02 eth
  uint256 public maxSupply = 5000;
  uint256 public maxMintAmount = 10;

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

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

  function mint(address _to, uint256 _mintAmount) public payable {
        uint256 supply = totalSupply();
        require(_mintAmount > 0);
        require(_mintAmount <= maxMintAmount);
        require(supply + _mintAmount <= maxSupply);

        if (msg.sender != owner()) {
             if (supply + _mintAmount > 200) { 
                require(msg.value >= cost * _mintAmount);
            } else {
                require(_mintAmount == 1);
            }
        }
        
        for (uint256 i = 1; i <= _mintAmount; i++) {
            _safeMint(_to, supply + i);
        }
    }
  
    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"
        );

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

  //only owner
  function setCost(uint256 _newCost) public onlyOwner {
    cost = _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 withdrawAll() external onlyOwner {
        uint balance = address(this).balance;
        payable(msg.sender).transfer(balance);
    }
}
function _baseURI() internal view virtual override returns (string memory) {
  return baseURI;
}

// internal