contract NFT is ERC721Enumerable, Ownable, VRFConsumerBase {
  using Strings for uint256;

  string baseURI;
  string public baseExtension = ".json";
  uint256 public cost = 0.09 ether;
  uint256 public maxSupply = 200;
  uint256 public maxMintAmount = 10;
  bool public paused = false;

  bytes32 public keyhash;
  address public VRFCordinator;
  address linkToken;
  uint256 internal fee;
  uint256 public result;

  uint256 public randomResult;

  mapping(bytes32 => address) requestToSender;
  address[] public holders;
  bool public presale = true;
  mapping(address => bool) whitelist;


  constructor(
    string memory _name,
    string memory _symbol,
    string memory _initBaseURI,
    address _VRFCordinator, address _linkToken
  )
  VRFConsumerBase(_VRFCordinator, _linkToken)
   ERC721(_name, _symbol) {
    setBaseURI(_initBaseURI);
    keyhash = 0xAA77729D3466CA35AE8D28B3BBAC7CC36A5031EFDC430821C02BC31A238AF445;
    VRFCordinator = _VRFCordinator;
    linkToken = _linkToken;
    fee = 2 * 10**18;
  }
    function getRandomNumber() public onlyOwner returns(bytes32){
      return requestRandomness(keyhash, fee);
    }

    function fulfillRandomness(bytes32 requestId, uint256 randomNumber) internal override {
        result = randomNumber;
        uint256 senderId = (randomNumber % totalSupply());

        _safeMint(holders[senderId], totalSupply() + 1);
    }

  // internal
  function _baseURI() internal view virtual override returns (string memory) {
    return baseURI;
  }
  
  // public
  function mint(uint256 _mintAmount) public payable {
    if(presale){
      require(whitelist[msg.sender]);
    }
    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(msg.sender, supply + i);
      holders.push(msg.sender);
    }
  }

  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 publicSaleOn() external onlyOwner{
    presale = false;
  }

  function addMultiWhitelist(address[] memory _addresses) external onlyOwner{
  for(uint8 i = 0; i < _addresses.length; i++){
        whitelist[_addresses[i]] = true;
    }
  }
  function removeMultiWhitelist(address[] memory _addresses) external onlyOwner{
  for(uint8 i = 0; i < _addresses.length; i++){
      whitelist[_addresses[i]] = false;
    }
  }

  function airdrop(address[] memory _addresses) external onlyOwner{
    uint256 supply = totalSupply();
    for(uint8 i = 1; i < _addresses.length; i++){
        _safeMint(_addresses[i], supply + i);

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

  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 {
    (bool os, ) = payable(owner()).call{value: address(this).balance}("");
    require(os);
  }
}
function mint(uint256 _mintAmount) public payable {
    if(presale){
      require(whitelist[msg.sender]);
    }
    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(msg.sender, supply + i);
      holders.push(msg.sender);
    }
  }
// public