// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}


// File @openzeppelin/contracts/access/[email protected]


// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)




abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    
    constructor() {
        _transferOwnership(_msgSender());
    }

    
    function owner() public view virtual returns (address) {
        return _owner;
    }

   
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}


// File @openzeppelin/contracts/utils/[email protected]


// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)




library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    
    function toString(uint256 value) internal pure returns (string memory) {
        

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}





// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)




interface IERC165 {
    
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}





// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)




interface IERC721 is IERC165 {
    
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    
    function balanceOf(address owner) external view returns (uint256 balance);

    
    function ownerOf(uint256 tokenId) external view returns (address owner);

    
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    
    function approve(address to, uint256 tokenId) external;

    
    function getApproved(uint256 tokenId) external view returns (address operator);

    
    function setApprovalForAll(address operator, bool _approved) external;

    
    function isApprovedForAll(address owner, address operator) external view returns (bool);

    
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;
}





// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)




interface IERC721Receiver {
    
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}




// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)




interface IERC721Metadata is IERC721 {
    
    function name() external view returns (string memory);

    
    function symbol() external view returns (string memory);

    
    function tokenURI(uint256 tokenId) external view returns (string memory);
}





// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Enumerable.sol)




interface IERC721Enumerable is IERC721 {
    
    function totalSupply() external view returns (uint256);

    
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);

    
    function tokenByIndex(uint256 index) external view returns (uint256);
}


// OpenZeppelin Contracts v4.4.1 (utils/Counters.sol)


library Counters {
    struct Counter {
        
        uint256 _value; 
    }

    function current(Counter storage counter) internal view returns (uint256) {
        return counter._value;
    }

    function increment(Counter storage counter) internal {
        unchecked {
            counter._value += 1;
        }
    }

    function decrement(Counter storage counter) internal {
        uint256 value = counter._value;
        require(value > 0, "Counter: decrement overflow");
        unchecked {
            counter._value = value - 1;
        }
    }

    function reset(Counter storage counter) internal {
        counter._value = 0;
    }
}


// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)




library Address {
    
    function isContract(address account) internal view returns (bool) {
        

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

    
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            
            if (returndata.length > 0) {
                

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}




// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)




abstract contract ERC165 is IERC165 {
    
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}


// File contracts/ERC721A.sol




contract ERC721A is Context, ERC165, IERC721, IERC721Metadata, IERC721Enumerable {
    using Address for address;
    using Strings for uint256;

    struct TokenOwnership {
        address addr;
        uint64 startTimestamp;
    }

    struct AddressData {
        uint128 balance;
        uint128 numberMinted;
    }

    uint256 internal currentIndex = 0;

    
    string private _name;

    
    string private _symbol;

    
    mapping(uint256 => TokenOwnership) internal _ownerships;

    
    mapping(address => AddressData) private _addressData;

    
    mapping(uint256 => address) private _tokenApprovals;

    
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    
    function totalSupply() public view override returns (uint256) {
        return currentIndex;
    }

    
    function tokenByIndex(uint256 index) public view override returns (uint256) {
        require(index < totalSupply(), 'ERC721A: global index out of bounds');
        return index;
    }

    
    function tokenOfOwnerByIndex(address owner, uint256 index) public view override returns (uint256) {
        require(index < balanceOf(owner), 'ERC721A: owner index out of bounds');
        uint256 numMintedSoFar = totalSupply();
        uint256 tokenIdsIdx = 0;
        address currOwnershipAddr = address(0);
        for (uint256 i = 0; i < numMintedSoFar; i++) {
            TokenOwnership memory ownership = _ownerships[i];
            if (ownership.addr != address(0)) {
                currOwnershipAddr = ownership.addr;
            }
            if (currOwnershipAddr == owner) {
                if (tokenIdsIdx == index) {
                    return i;
                }
                tokenIdsIdx++;
            }
        }
        revert('ERC721A: unable to get token of owner by index');
    }

    
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            interfaceId == type(IERC721Enumerable).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    
    function balanceOf(address owner) public view override returns (uint256) {
        require(owner != address(0), 'ERC721A: balance query for the zero address');
        return uint256(_addressData[owner].balance);
    }

    function _numberMinted(address owner) internal view returns (uint256) {
        require(owner != address(0), 'ERC721A: number minted query for the zero address');
        return uint256(_addressData[owner].numberMinted);
    }

    function ownershipOf(uint256 tokenId) internal view returns (TokenOwnership memory) {
        require(_exists(tokenId), 'ERC721A: owner query for nonexistent token');

        for (uint256 curr = tokenId; ; curr--) {
            TokenOwnership memory ownership = _ownerships[curr];
            if (ownership.addr != address(0)) {
                return ownership;
            }
        }

        revert('ERC721A: unable to determine the owner of token');
    }

    
    function ownerOf(uint256 tokenId) public view override returns (address) {
        return ownershipOf(tokenId).addr;
    }

    
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), 'ERC721Metadata: URI query for nonexistent token');

        string memory baseURI = _baseURI();
        return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : '';
    }

    
    function _baseURI() internal view virtual returns (string memory) {
        return '';
    }

    
    function approve(address to, uint256 tokenId) public override {
        address owner = ERC721A.ownerOf(tokenId);
        require(to != owner, 'ERC721A: approval to current owner');

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            'ERC721A: approve caller is not owner nor approved for all'
        );

        _approve(to, tokenId, owner);
    }

    
    function getApproved(uint256 tokenId) public view override returns (address) {
        require(_exists(tokenId), 'ERC721A: approved query for nonexistent token');

        return _tokenApprovals[tokenId];
    }

    
    function setApprovalForAll(address operator, bool approved) public override {
        require(operator != _msgSender(), 'ERC721A: approve to caller');

        _operatorApprovals[_msgSender()][operator] = approved;
        emit ApprovalForAll(_msgSender(), operator, approved);
    }

    
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public override {
        _transfer(from, to, tokenId);
    }

        function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public override {
        safeTransferFrom(from, to, tokenId, '');
    }

    
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) public override {
        _transfer(from, to, tokenId);
        require(
            _checkOnERC721Received(from, to, tokenId, _data),
            'ERC721A: transfer to non ERC721Receiver implementer'
        );
    }

    
    function _exists(uint256 tokenId) internal view returns (bool) {
        return tokenId < currentIndex;
    }

    function _safeMint(address to, uint256 quantity) internal {
        _safeMint(to, quantity, '');
    }

    
    function _safeMint(
        address to,
        uint256 quantity,
        bytes memory _data
    ) internal {
        uint256 startTokenId = currentIndex;
        require(to != address(0), 'ERC721A: mint to the zero address');
        require(!_exists(startTokenId), 'ERC721A: token already minted');
        require(quantity > 0, 'ERC721A: quantity must be greater 0');

        _beforeTokenTransfers(address(0), to, startTokenId, quantity);

        AddressData memory addressData = _addressData[to];
        _addressData[to] = AddressData(
            addressData.balance + uint128(quantity),
            addressData.numberMinted + uint128(quantity)
        );
        _ownerships[startTokenId] = TokenOwnership(to, uint64(block.timestamp));

        uint256 updatedIndex = startTokenId;

        for (uint256 i = 0; i < quantity; i++) {
            emit Transfer(address(0), to, updatedIndex);
            require(
                _checkOnERC721Received(address(0), to, updatedIndex, _data),
                'ERC721A: transfer to non ERC721Receiver implementer'
            );
            updatedIndex++;
        }

      currentIndex = updatedIndex;
        _afterTokenTransfers(address(0), to, startTokenId, quantity);
    }

    
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) private {
        TokenOwnership memory prevOwnership = ownershipOf(tokenId);

        bool isApprovedOrOwner = (_msgSender() == prevOwnership.addr ||
            getApproved(tokenId) == _msgSender() ||
            isApprovedForAll(prevOwnership.addr, _msgSender()));

        require(isApprovedOrOwner, 'ERC721A: transfer caller is not owner nor approved');

        require(prevOwnership.addr == from, 'ERC721A: transfer from incorrect owner');
        require(to != address(0), 'ERC721A: transfer to the zero address');

        _beforeTokenTransfers(from, to, tokenId, 1);

        
        _approve(address(0), tokenId, prevOwnership.addr);

        
        unchecked {
            _addressData[from].balance -= 1;
            _addressData[to].balance += 1;
        }

        _ownerships[tokenId] = TokenOwnership(to, uint64(block.timestamp));

        
        uint256 nextTokenId = tokenId + 1;
        if (_ownerships[nextTokenId].addr == address(0)) {
            if (_exists(nextTokenId)) {
                _ownerships[nextTokenId] = TokenOwnership(prevOwnership.addr, prevOwnership.startTimestamp);
            }
        }

        emit Transfer(from, to, tokenId);
        _afterTokenTransfers(from, to, tokenId, 1);
    }

    
    function _approve(
        address to,
        uint256 tokenId,
        address owner
    ) private {
        _tokenApprovals[tokenId] = to;
        emit Approval(owner, to, tokenId);
    }

    
    function _checkOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) private returns (bool) {
        if (to.isContract()) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
                return retval == IERC721Receiver(to).onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert('ERC721A: transfer to non ERC721Receiver implementer');
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

    
    function _beforeTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual {}

    
    function _afterTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual {}
}

contract Crypto is ERC721A, Ownable {

  using Strings for uint256;
  using Counters for Counters.Counter;

  Counters.Counter private supply;

 string baseURI;
  string public baseExtension = ".json";
  uint256 public constant MAX_PER_TX_FREE = 2;
  uint256 public constant MAX_PER_TX = 2;
  uint256 public constant FREE_MAX_SUPPLY = 2000;
  uint256 public cost = 0.002 ether;
  uint256 public maxSupply = 6000;
  uint256 public maxMintAmount = 4;
  bool public paused = true;
  bool public revealed = false;
  string public notRevealedUri;

  constructor(
    string memory _name,
    string memory _symbol,
    string memory _initBaseURI,
    string memory _initNotRevealedUri
  ) ERC721A(_name, _symbol) {
    setBaseURI(_initBaseURI);
    setNotRevealedURI(_initNotRevealedUri);
  }

  // internal
  function _baseURI() internal view virtual override returns (string memory) {
    return baseURI;
  }

  // public
  function mint(uint256 _amount) external payable {
        address _caller = _msgSender();
        require(!paused, "Paused");
        require(maxSupply >= totalSupply() + _amount, "Exceeds max supply");
        require(_amount > 0, "No 0 mints");
        require(tx.origin == _caller, "No contracts");

        if(FREE_MAX_SUPPLY >= totalSupply()){
            require(MAX_PER_TX_FREE >= _amount , "Excess max per free tx");
        }else{
            require(MAX_PER_TX >= _amount , "Excess max per paid tx");
            require(_amount * cost == msg.value, "Invalid funds provided");
        }

        _safeMint(_caller, _amount);
    }

  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 setCost(uint256 _newCost) public onlyOwner {
    cost = _newCost;
  }

  function setmaxMintAmount(uint256 _newmaxMintAmount) public onlyOwner {
    maxMintAmount = _newmaxMintAmount;
  }
  
  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 withdraw() public onlyOwner {
        (bool os, ) = payable(owner()).call{value: address(this).balance}("");
        require(os, "Withdraw failed!");
  }
  function _mintLoop(address _receiver, uint256 _mintAmount) internal {
    for (uint256 i = 1; i <= _mintAmount; i++) {
      supply.increment();
      _safeMint(_receiver, supply.current());
    }
  }

  

    
}