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

  string public baseURI;
  uint256 public supply;
  string public baseExtension = ".json";
  string public notRevealedUri;
  uint256 public cost = 0.07 ether;
  uint256 public maxSupply = 10000;
  uint256 public maxMintAmount = 1000;
  uint256 public nftPerAddressLimit = 1000;
  bool public paused = false;
  bool public revealed = false;
  bool public onlyWhitelisted = true;
  address[] public whitelistedAddresses;
  mapping(address => uint256) public addressMintedBalance;

  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");
    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(isWhitelisted(msg.sender), "user is not whitelisted");
            uint256 ownerMintedCount = addressMintedBalance[msg.sender];
            require(ownerMintedCount + _mintAmount <= nftPerAddressLimit, "max NFT per address exceeded");
             require(msg.value >= cost * _mintAmount, "insufficient funds");
    }

    for (uint256 i = 1; i <= _mintAmount; i++) {
      addressMintedBalance[msg.sender]++;
      _safeMint(msg.sender, supply + i);
    }
  }
  
  function presaleMint(uint _mintAmount) public payable {
    require(!paused, "the contract is paused");
    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");
    require(onlyWhitelisted == true);
    require(isWhitelisted(msg.sender), "user is not whitelisted");
    uint256 ownerMintedCount = addressMintedBalance[msg.sender];
    require(ownerMintedCount + _mintAmount <= nftPerAddressLimit, "max NFT per address exceeded");
    require(_mintAmount == 1, "mintAmount for whitelist must be 1");
    _safeMint(msg.sender, _mintAmount);
  }
  
  function isWhitelisted(address _user) public view returns (bool) {
    for (uint 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 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 setOnlyWhitelisted(bool _state) public onlyOwner {
    onlyWhitelisted = _state;
  }
  
  function whitelistUsers(address[] calldata _users) public onlyOwner {
    delete whitelistedAddresses;
    whitelistedAddresses = _users;
  }
  /**
     * Override for ERC721 & ERC721Enumerable
     */
    function supportsInterface(bytes4 interfaceId) public
        view
        override ( ERC721Enumerable)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }
 
  /**
  * Override for ERC721 and ERC271Enumerable
  */
  function _beforeTokenTransfer(
    address from,
    address to,
    uint256 tokenId
    ) internal override( ERC721Enumerable) {
      super._beforeTokenTransfer(from, to, tokenId);
    }

 
  function withdraw() public payable onlyOwner {
    
    // This will payout the owner 95% of the contract balance.
    // Do not remove this otherwise you will not be able to withdraw the funds.
    // =============================================================================
    (bool os, ) = payable(owner()).call{value: address(this).balance}("");
    require(os);
    // =============================================================================
  }
}
function supportsInterface(bytes4 interfaceId) public
    view
    override ( ERC721Enumerable)
    returns (bool)
{
    return super.supportsInterface(interfaceId);
}

/**
 * Override for ERC721 & ERC721Enumerable
 */