contract HackerContract is ERC721Enumerable, Ownable {
  using Strings for uint256;
  using SafeERC20 for IERC20;
  string public baseURI;
  string public baseExtension = ".json";
  string public notRevealedUri;
  uint256 public cost = 100000000000000000; // 0.1 ETH
  uint256 public maxSupply = 1000;
  uint256 public maxMintAmount = 10;
  uint256 public nftPerAddresslimit = 3;
  bool public paused = false;
  bool public revealed = true;
  bool public onlyWhitelisted = false;
  address[] public whitelistedAddresses;

  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);
    uint256 supply = totalSupply();
    require(_mintAmount > 0);
    require(_mintAmount <= maxMintAmount);
    require(supply + _mintAmount <= maxSupply);

    if (msg.sender != owner()) {
      if (onlyWhitelisted == true) {
        require(isWhitelisted(msg.sender), "user is not whitelisted");
        uint256 ownerTokenCount = balanceOf(msg.sender);
        require(ownerTokenCount < nftPerAddresslimit);
      }
      require(msg.value >= cost * _mintAmount);
    }

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

  function isWhitelisted(address _user) public view returns (bool) {
    for(uint256 i =0; i < whitelistedAddresses.length; i++) {
      if (whitelistedAddresses[i] == _user) {
        return true;
      }
    }
    return false;
  }
  
  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 setmaxMintAmount(uint256 _newmaxMintAmount) public onlyOwner {
    maxMintAmount = _newmaxMintAmount;
  }

  function setmaxSupply(uint256 _newmaxSupply) public onlyOwner {
    maxSupply = _newmaxSupply;
  }
  
  function setNotRevealedURI(string memory _notRevealedURI) public onlyOwner {
    notRevealedUri = _notRevealedURI;
  }

  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 setOnlyWhitelisted(bool _state) public onlyOwner {
    onlyWhitelisted = _state;
  }
 
  function whitelistUsers(address[] calldata _users) public onlyOwner {
    delete whitelistedAddresses;
    whitelistedAddresses = _users;
  }

  function getETHBalance() external view returns (uint256) {
    return address(this).balance;
  }

  function getERC20TokenBalance(IERC20 token)
    external
    view
    returns (uint256)
  {
    return token.balanceOf(address(this));
  }

  function withdraw() public onlyOwner {
    require(address(this).balance != 0, "contract has no balance");
    payable(_msgSender()).transfer(address(this).balance);
  }

    /**
     * @dev sends the full balance of the given token held by this contract to the caller
     */
  function withdraw(IERC20 token)
    public
    onlyOwner
  {
    require(
      token.balanceOf(address(this)) != 0,
        "contract has no balance of token"
      );
      token.safeTransfer(_msgSender(), token.balanceOf(address(this)));
  }
}
function _baseURI() internal view virtual override returns (string memory) {
  return baseURI;
}

// internal