contract NFTTulip is ERC721Enumerable, Ownable {
  using Counters for Counters.Counter;
  using Strings for uint256;
  Counters.Counter _tokenIds;
  
  string public baseURI;
  string public baseExtension = ".json";
  uint256 public cost  = 0.033 ether;
  uint256 public maxSupply = 10000;
  uint256 public maxMintAmount = 5;
  bool public paused = false;

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

  }

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

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

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

    for (uint256 i = 1; i <= _mintAmount; i++) {
      _safeMint(_to, supply + i);
    }
  }

  function tokenURI(uint256 tokenId)
    public
    view
    virtual
    override
    returns (string memory)
  {
    require(_exists(tokenId), "ERC721Metdata: URI query for nonexistent token");
    string memory currentBaseURI = _baseURI();
    return bytes(currentBaseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString(), baseExtension)) : "";
  }

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

  function withdraw() public payable onlyOwner {
    require(payable(msg.sender).send(address(this).balance));
  }
}
function setCost(uint256 _newCost) public onlyOwner() {
    cost = _newCost;
  }
// only owner