/*
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    ░      ▒   ▒▒ ░ ▒ ░░ ░▒ ▒░ ░ ░  ░   ░    ░ ░▒  ░ ░░░▒░ ░ ░ 
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*/
// SPDX-License-Identifier: MIT
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;
    }
}

abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor() {
        _setOwner(_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 {
        _setOwner(address(0));
    }

    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

interface IERC165 {

    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

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;
}

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);
}


abstract contract ERC165 is IERC165 {
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

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);
    }
}

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);
            }
        }
    }
}

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);
}

interface IERC721Receiver {

    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;

    string private _name;

    string private _symbol;

    mapping(uint256 => address) private _owners;

    mapping(address => uint256) private _balances;

    mapping(uint256 => address) private _tokenApprovals;

    mapping(address => mapping(address => bool)) private _operatorApprovals;

    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: balance query for the zero address");
        return _balances[owner];
    }

    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _owners[tokenId];
        require(owner != address(0), "ERC721: owner query for nonexistent token");
        return owner;
    }

    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 virtual override {
        address owner = ERC721.ownerOf(tokenId);
        require(to != owner, "ERC721: approval to current owner");

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            "ERC721: approve caller is not owner nor approved for all"
        );

        _approve(to, tokenId);
    }

    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), "ERC721: approved query for nonexistent token");

        return _tokenApprovals[tokenId];
    }

    function setApprovalForAll(address operator, bool approved) public virtual override {
        require(operator != _msgSender(), "ERC721: 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 virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");

        _transfer(from, to, tokenId);
    }

    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        _safeTransfer(from, to, tokenId, _data);
    }

    function _safeTransfer(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) internal virtual {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _owners[tokenId] != address(0);
    }

    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        require(_exists(tokenId), "ERC721: operator query for nonexistent token");
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
    }

    function _safeMint(address to, uint256 tokenId) internal virtual {
        _safeMint(to, tokenId, "");
    }

    function _safeMint(
        address to,
        uint256 tokenId,
        bytes memory _data
    ) internal virtual {
        _mint(to, tokenId);
        require(
            _checkOnERC721Received(address(0), to, tokenId, _data),
            "ERC721: transfer to non ERC721Receiver implementer"
        );
    }

    function _mint(address to, uint256 tokenId) internal virtual {
        require(to != address(0), "ERC721: mint to the zero address");
        require(!_exists(tokenId), "ERC721: token already minted");

        _beforeTokenTransfer(address(0), to, tokenId);

        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(address(0), to, tokenId);
    }

    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721.ownerOf(tokenId);

        _beforeTokenTransfer(owner, address(0), tokenId);

        _approve(address(0), tokenId);

        _balances[owner] -= 1;
        delete _owners[tokenId];

        emit Transfer(owner, address(0), tokenId);
    }

    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {
        require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own");
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId);

        _approve(address(0), tokenId);

        _balances[from] -= 1;
        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(from, to, tokenId);
    }

    function _approve(address to, uint256 tokenId) internal virtual {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721.ownerOf(tokenId), 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.onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("ERC721: transfer to non ERC721Receiver implementer");
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}
}

abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
    mapping(address => mapping(uint256 => uint256)) private _ownedTokens;

    mapping(uint256 => uint256) private _ownedTokensIndex;

    uint256[] private _allTokens;

    mapping(uint256 => uint256) private _allTokensIndex;

    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
        return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
    }

    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721.balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
        return _ownedTokens[owner][index];
    }

    function totalSupply() public view virtual override returns (uint256) {
        return _allTokens.length;
    }

    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721Enumerable.totalSupply(), "ERC721Enumerable: global index out of bounds");
        return _allTokens[index];
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual override {
        super._beforeTokenTransfer(from, to, tokenId);

        if (from == address(0)) {
            _addTokenToAllTokensEnumeration(tokenId);
        } else if (from != to) {
            _removeTokenFromOwnerEnumeration(from, tokenId);
        }
        if (to == address(0)) {
            _removeTokenFromAllTokensEnumeration(tokenId);
        } else if (to != from) {
            _addTokenToOwnerEnumeration(to, tokenId);
        }
    }

    function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
        uint256 length = ERC721.balanceOf(to);
        _ownedTokens[to][length] = tokenId;
        _ownedTokensIndex[tokenId] = length;
    }

    function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
        _allTokensIndex[tokenId] = _allTokens.length;
        _allTokens.push(tokenId);
    }

    function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {

        uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;
        uint256 tokenIndex = _ownedTokensIndex[tokenId];

        if (tokenIndex != lastTokenIndex) {
            uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];

            _ownedTokens[from][tokenIndex] = lastTokenId; 
            _ownedTokensIndex[lastTokenId] = tokenIndex;
        }


        delete _ownedTokensIndex[tokenId];
        delete _ownedTokens[from][lastTokenIndex];
    }

    function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {

        uint256 lastTokenIndex = _allTokens.length - 1;
        uint256 tokenIndex = _allTokensIndex[tokenId];

        uint256 lastTokenId = _allTokens[lastTokenIndex];

        _allTokens[tokenIndex] = lastTokenId;
        _allTokensIndex[lastTokenId] = tokenIndex;

        delete _allTokensIndex[tokenId];
        _allTokens.pop();
    }
}

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 private currentIndex = 0;

  uint256 internal immutable collectionSize;
  uint256 internal immutable maxBatchSize;

  string private _name;

  string private _symbol;

  mapping(uint256 => TokenOwnership) private _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_,
    uint256 maxBatchSize_,
    uint256 collectionSize_
  ) {
    require(
      collectionSize_ > 0,
      "ERC721A: collection must have a nonzero supply"
    );
    require(maxBatchSize_ > 0, "ERC721A: max batch size must be nonzero");
    _name = name_;
    _symbol = symbol_;
    maxBatchSize = maxBatchSize_;
    collectionSize = collectionSize_;
  }

  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");

    uint256 lowestTokenToCheck;
    if (tokenId >= maxBatchSize) {
      lowestTokenToCheck = tokenId - maxBatchSize + 1;
    }

    for (uint256 curr = tokenId; curr >= lowestTokenToCheck; 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");
    // We know if the first token in the batch doesn't exist, the other ones don't as well, because of serial ordering.
    require(!_exists(startTokenId), "ERC721A: token already minted");
    require(quantity <= maxBatchSize, "ERC721A: quantity to mint too high");

    _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);

    _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);
  }

  uint256 public nextOwnerToExplicitlySet = 0;

  function _setOwnersExplicit(uint256 quantity) internal {
    uint256 oldNextOwnerToSet = nextOwnerToExplicitlySet;
    require(quantity > 0, "quantity must be nonzero");
    uint256 endIndex = oldNextOwnerToSet + quantity - 1;
    if (endIndex > collectionSize - 1) {
      endIndex = collectionSize - 1;
    }

    require(_exists(endIndex), "not enough minted yet for this cleanup");
    for (uint256 i = oldNextOwnerToSet; i <= endIndex; i++) {
      if (_ownerships[i].addr == address(0)) {
        TokenOwnership memory ownership = ownershipOf(i);
        _ownerships[i] = TokenOwnership(
          ownership.addr,
          ownership.startTimestamp
        );
      }
    }
    nextOwnerToExplicitlySet = endIndex + 1;
  }

  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 {}
}

abstract contract ReentrancyGuard {

    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    modifier nonReentrant() {
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
        _status = _ENTERED;
        _;
        _status = _NOT_ENTERED;
    }
}

library MerkleProof {

    function verify(
        bytes32[] memory proof,
        bytes32 root,
        bytes32 leaf
    ) internal pure returns (bool) {
        return processProof(proof, leaf) == root;
    }

    function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
        bytes32 computedHash = leaf;
        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];
            if (computedHash <= proofElement) {
                // Hash(current computed hash + current element of the proof)
                computedHash = _efficientHash(computedHash, proofElement);
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = _efficientHash(proofElement, computedHash);
            }
        }
        return computedHash;
    }

    function _efficientHash(bytes32 a, bytes32 b) private pure returns (bytes32 value) {
        assembly {
            mstore(0x00, a)
            mstore(0x20, b)
            value := keccak256(0x00, 0x40)
        }
    }
}

contract Taiketsu is ERC721A, Ownable, ReentrancyGuard{
    
    using Strings for uint256;
    
    uint256 public constant MAX_SUPPLY = 5889;
    uint public publicSalePrice = 0.1 ether;
    uint public preSalePrice = 0.08 ether;
    
    address public preordersDataContract = 0x1815a17ABe7630045133051aD7cB905b25d57AE9;

    bool public isPublicSaleActive;
    bool public isPreSaleActive;
    bool public isPreorderMintActive;

    uint256 public maxPublicSalesPerTransaction = 3;
    uint256 public maxPreSalesPerAddress = 2;
    uint256 private maxOwnerMint = 10;
    
    bytes32 public preSaleMerkleRoot;
    mapping(address => uint256) private preSalesCounter;
    mapping(address => bool) private preordersCheck;
    uint256 private ownerMintCounter;

    uint256 public preordersCounter;
    bool isPreordersCounterLoaded;

    string private _baseTokenURI;

    constructor() ERC721A("Taiketsu", "TAIKETSU", 3, MAX_SUPPLY)  {
      
    }

    function publicSale(uint256 _count) public payable nonReentrant {
        require(totalSupply() < MAX_SUPPLY, "Sale end");
        require(isPublicSaleActive, "Public sales is closed");
        require(totalSupply() + _count <= MAX_SUPPLY - preordersCounter, "Exceeds MAX limit");
        require(_count <= maxPublicSalesPerTransaction, "Exceeds TX limit");
        require(msg.value == _count * publicSalePrice, "Value below price");
        _safeMint(_msgSender(), _count);
    }

    function preSale(uint256 _count, bytes32[] calldata _merkleProof) public payable nonReentrant {
        require(totalSupply() < MAX_SUPPLY, "Sale end");
        require(isPreSaleActive, "Presale is closed");
        require(totalSupply() + _count <= MAX_SUPPLY - preordersCounter, "Exceeds MAX limit");
        require(_count + preSalesCounter[_msgSender()] <= maxPreSalesPerAddress, "Exceeds address limit");
        require(_verify(_merkleProof, _msgSender()), "Invalid proof");
        require(msg.value == preSalePrice * _count, "Value below price");
        preSalesCounter[_msgSender()] += _count;
        _safeMint(_msgSender(), _count);
    }

    function mintPreorder() public nonReentrant {
        require(totalSupply() < MAX_SUPPLY, "Sale end");
        require(isPreorderMintActive, "Preorders mint is closed");
        uint256 _preorders = preordersAtAddress(msg.sender);
        require(_preorders > 0, "No preorders");
        require(!preordersCheck[msg.sender], "Already minted");
        preordersCheck[msg.sender] = true;
        preordersCounter -= _preorders;
        _safeMint(msg.sender, _preorders);
    }

    function _baseURI() internal view virtual override returns (string memory) {
        return _baseTokenURI;
    }

    function preordersAtAddress(address _address) public view returns(uint256) {
        if (preordersCheck[_address]){
          return 0;
        } else {
          return PREORDERS(preordersDataContract).preordersAtAddress(_address);
        }
    }

    function presalesAtAddress(address _address) public view returns(uint256) {
        return preSalesCounter[_address];
    }
    
    function tokensOfOwner(address _owner) external view returns(uint256[] memory) {
        uint tokenCount = balanceOf(_owner);
        uint256[] memory tokensId = new uint256[](tokenCount);
        for(uint i = 0; i < tokenCount; i++){
            tokensId[i] = tokenOfOwnerByIndex(_owner, i);
        }
        return tokensId;
    }

    function _verify(bytes32[] calldata merkleProof, address sender) private view returns (bool) {
        bytes32 leaf = keccak256(abi.encodePacked(sender));
        return MerkleProof.verify(merkleProof, preSaleMerkleRoot, leaf);
    }
    
    function ownerMint(address _to, uint256 _count) public onlyOwner{
        require(totalSupply() < MAX_SUPPLY, "Sale end");
        require(_count + ownerMintCounter <= maxOwnerMint, "Exceeds owner mint limit");
        ownerMintCounter += _count;
        _safeMint(_to, _count);
    }

    function setBaseURI(string memory baseURI) public onlyOwner {
        _baseTokenURI = baseURI;
    }

    function setStatusPublicSale(bool _status) public onlyOwner {
        isPublicSaleActive = _status;
    }

    function setStatusPreMint(bool _statusPreSale, bool _statusPreorders) public onlyOwner {
        isPreSaleActive = _statusPreSale;
        isPreorderMintActive = _statusPreorders;
        if (!isPreordersCounterLoaded){
          preordersCounter = PREORDERS(preordersDataContract).preordersCounter();
          isPreordersCounterLoaded = true;
        }
    }

    function setPreSalesLimit(uint256 _count) public onlyOwner {
        maxPreSalesPerAddress = _count;
    }

    function setMerkleRoot(bytes32 _merkleRoot) public onlyOwner {
        preSaleMerkleRoot = _merkleRoot;
    }

    function withdrawAll() public payable onlyOwner{
        address cofounder = 0xD03c810C126B4f6E18e98A1EC29131605882Dc13;
        uint256 cofounder_value = address(this).balance / 100 * 50;
        uint256 owner_value = address(this).balance - cofounder_value;
        require(payable(cofounder).send(cofounder_value));
        require(payable(owner()).send(owner_value));
    }

}

interface PREORDERS{
    function preordersCounter() external view returns (uint256);
    function preordersAtAddress(address _address) external view returns (uint256);
}