// File: contracts/core/PandaVRFProducer.sol



/*
 **                                                                                                                                                              
 **                                                                   dddddddd                                                                                   
 **  PPPPPPPPPPPPPPPPP                                                d::::::d                  DDDDDDDDDDDDD                  AAA                 OOOOOOOOO     
 **  P::::::::::::::::P                                               d::::::d                  D::::::::::::DDD              A:::A              OO:::::::::OO   
 **  P::::::PPPPPP:::::P                                              d::::::d                  D:::::::::::::::DD           A:::::A           OO:::::::::::::OO 
 **  PP:::::P     P:::::P                                             d:::::d                   DDD:::::DDDDD:::::D         A:::::::A         O:::::::OOO:::::::O
 **    P::::P     P:::::Paaaaaaaaaaaaa  nnnn  nnnnnnnn        ddddddddd:::::d   aaaaaaaaaaaaa     D:::::D    D:::::D       A:::::::::A        O::::::O   O::::::O
 **    P::::P     P:::::Pa::::::::::::a n:::nn::::::::nn    dd::::::::::::::d   a::::::::::::a    D:::::D     D:::::D     A:::::A:::::A       O:::::O     O:::::O
 **    P::::PPPPPP:::::P aaaaaaaaa:::::an::::::::::::::nn  d::::::::::::::::d   aaaaaaaaa:::::a   D:::::D     D:::::D    A:::::A A:::::A      O:::::O     O:::::O
 **    P:::::::::::::PP           a::::ann:::::::::::::::nd:::::::ddddd:::::d            a::::a   D:::::D     D:::::D   A:::::A   A:::::A     O:::::O     O:::::O
 **    P::::PPPPPPPPP      aaaaaaa:::::a  n:::::nnnn:::::nd::::::d    d:::::d     aaaaaaa:::::a   D:::::D     D:::::D  A:::::A     A:::::A    O:::::O     O:::::O
 **    P::::P            aa::::::::::::a  n::::n    n::::nd:::::d     d:::::d   aa::::::::::::a   D:::::D     D:::::D A:::::AAAAAAAAA:::::A   O:::::O     O:::::O
 **    P::::P           a::::aaaa::::::a  n::::n    n::::nd:::::d     d:::::d  a::::aaaa::::::a   D:::::D     D:::::DA:::::::::::::::::::::A  O:::::O     O:::::O
 **    P::::P          a::::a    a:::::a  n::::n    n::::nd:::::d     d:::::d a::::a    a:::::a   D:::::D    D:::::DA:::::AAAAAAAAAAAAA:::::A O::::::O   O::::::O
 **  PP::::::PP        a::::a    a:::::a  n::::n    n::::nd::::::ddddd::::::dda::::a    a:::::a DDD:::::DDDDD:::::DA:::::A             A:::::AO:::::::OOO:::::::O
 **  P::::::::P        a:::::aaaa::::::a  n::::n    n::::n d:::::::::::::::::da:::::aaaa::::::a D:::::::::::::::DDA:::::A               A:::::AOO:::::::::::::OO 
 **  P::::::::P         a::::::::::aa:::a n::::n    n::::n  d:::::::::ddd::::d a::::::::::aa:::aD::::::::::::DDD A:::::A                 A:::::A OO:::::::::OO   
 **  PPPPPPPPPP          aaaaaaaaaa  aaaa nnnnnn    nnnnnn   ddddddddd   ddddd  aaaaaaaaaa  aaaaDDDDDDDDDDDDD   AAAAAAA                   AAAAAAA  OOOOOOOOO     
 **  
*/
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.6;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

import "@chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol";
import "@chainlink/contracts/src/v0.8/interfaces/VRFCoordinatorV2Interface.sol";
import "@chainlink/contracts/src/v0.8/VRFConsumerBaseV2.sol";

import "../interfaces/IPoolKit.sol";
/**
 */

contract PandaVRFProducer is Ownable, ReentrancyGuard, VRFConsumerBaseV2 {
    using SafeERC20 for IERC20;
    struct RequestInfo {
        uint256 reqFunc;
        address sender;
        uint256 ownerTokenId;
        uint256 targetTokenId;
        uint256 amountFeeMax;
        uint256 deadline;
        uint256 reqState;
    }


    address immutable public pandaToken;
    address immutable public pandaNFT;
    IPoolKit public poolKit;
    bool public isVrfOpen = false;
    mapping(uint256 => RequestInfo) public reqInfos;
    mapping(address => uint256) public rebornMap;
    mapping(address => uint256) public buyMap;

    VRFCoordinatorV2Interface COORDINATOR;
    LinkTokenInterface LINKTOKEN;
    // Storage parameters
    // uint256 public requestId;
    uint64 public subscriptionId;
    // A reasonable default is 100000, but this value could be different
    // on other networks.
    uint32 callbackGasLimit = 250_000;
    uint256 public fixedGasPrice = 10 gwei;

    uint256 constant buyGas = 179_980;
    uint256 constant rebornGas = 179_980;
    uint256 public constant REBRON_FUNC_TYPE = 1;
    uint256 public constant BUY_FUNC_TYPE = 2;
    uint8 public constant GAS_LEVEL_CONTRACT = 1;
    uint8 public constant GAS_LEVEL_200 = 2;
    uint8 public constant GAS_LEVEL_500 = 3;
    uint8 public constant GAS_LEVEL_1000 = 4;

    uint8 public constant REQ_NOT_SEND = 0;
    uint8 public constant REQ_START = 1;
    uint8 public constant REQ_PENDING = 2;
    uint8 public constant REQ_FINISH = 3;

    address public constant ZERO_ADDRESS = address(0);
    uint256 public constant NFT_TOTAL_SUPPLY = 10000;

    uint256 public constant FEE_BASE = 10000;
    uint256 public poolFeeValue = 375;
    uint256 public treasuryFeeValue = 0;

    // The default is 3, but you can set this higher.
    uint16 constant requestConfirmations = 3;
    uint32 constant numWords =  1;
    // address constant vrfCoordinator = 0x6168499c0cFfCaCD319c818142124B7A15E857ab;
    //main net 
    address constant vrfCoordinator = 0x271682DEB8C4E0901D1a1550aD2e64D568E69909;
   
    // address constant link_token_contract = 0x01BE23585060835E02B77ef475b0Cc51aA1e0709;
    //main net 0x514910771AF9Ca656af840dff83E8264EcF986CA
    address constant link_token_contract = 0x514910771AF9Ca656af840dff83E8264EcF986CA;

    // bytes32 constant keyHash200 = 0xd89b2bf150e3b9e13446986e571fb9cab24b13cea0a43ea20a6049a85cc807cc;
    // bytes32 constant keyHash500 = 0xd89b2bf150e3b9e13446986e571fb9cab24b13cea0a43ea20a6049a85cc807cc;
    // bytes32 constant keyHash1000 = 0xd89b2bf150e3b9e13446986e571fb9cab24b13cea0a43ea20a6049a85cc807cc;

    //main net 
    bytes32 constant keyHash200 = 0x8af398995b04c28e9951adb9721ef74c74f93e6a478f39e7e0777be13527e7ef;
    bytes32 constant keyHash500 = 0xff8dedfbfa60af186cf3c830acbc32c05aae823045ae5ea7da1e45fbfaba4f92;
    bytes32 constant keyHash1000 = 0x9fe0eebf5e446e3c998ec9bb19951541aee00bb90ea201ae456421a2ded86805;


    event PreReborn(uint256 indexed requestId, address indexed recipient,uint256 ownerTokenId, uint256 fee);
    event PreBuy(uint256 indexed requestId, address indexed recipient, uint256 payAmount);
    event Reborn(address indexed recipient,uint256 ownerTokenId, uint256 targetTokenId);
    event Buy(address indexed recipient, uint256 targetTokenId);
    event WithdrawERC20(address recipient, address tokenAddress, uint256 tokenAmount);
    event WithdrawEther(address recipient, uint256 amount);
    event RandomOpened(address indexed sender, uint256 index, uint256 targetIndex, uint256 requestId, uint256 random);
    event NewSubscription(address consumer, uint256 subscriptionId);
    event TopUpSubscription(uint256 amount);
    event AddConsumer(address consumerAddress);
    event RemoveConsumer(address consumerAddress);
    event CancelSubscription(address receivingWallet, uint256 subscriptionId);
    event SwitchEvent(bool _vrfOpen);
    event FixedGasPrice(uint256 _gasPrice);
    event CallbackGasLimet(uint256 _limit);
    event SetPoolFeeValue(uint256 feeValue);
    event SetTreasuryFeeValue(uint256 feeValue);
    event Redeem(address indexed recipient, uint256 ownerTokenId, uint256 receiveAmount);
    



    error TimeOutError(uint256 deadline, uint256 timestamp);
    error ZeroAddrError();
    error NoEnoughCallbackGas(uint256 value, uint256 needGas);
    error PoolCloseError();
    error NFTOwnerNotMatch(uint tokenId, address expectOwner, address realOwner);
    error MaxFeeNotMatch(uint256 maxUserFee, uint256 poolNeedFee);
    error PandaNotEnough(address sender, uint256 balance, uint256 needBalance);
    error MaxBuyNotMatch(uint256 maxUserPayFor, uint256 poolNeedPayFor);
    error PoolNotEnoughNFT(uint256 poolBalance, uint256 downLimit);
    error TransferEhterFail(address sender, address receiver, uint256 amount);
    error ConcurrentRebornError(address sender, uint256 requistId);
    error RequestInvalid(address sender, uint256 requestId, uint256 targetTokenId);
    error MinReceiveNotMatch(uint256 exceptMinReceive, uint256 poolPayFor);


    
    modifier ensure(uint deadline) {
        if(deadline < block.timestamp) {
            revert TimeOutError(deadline, block.timestamp);
        }
        _;
    }

    modifier notZeroAddr(address addr_) {
        if(addr_ == ZERO_ADDRESS) {
            revert ZeroAddrError();
        }
        _;
    }

    modifier vrfOpen() {
        if(!isVrfOpen) {
            revert PoolCloseError();
        }
        _;
    }


    

     /**
     * @dev Constructor.
     */
    constructor(
        address _pandaCore,
        address _pandaToken,
        address _pandaNft
    ) VRFConsumerBaseV2(vrfCoordinator)
    {
        poolKit = IPoolKit(_pandaCore);
        pandaToken = _pandaToken;
        pandaNFT = _pandaNft;
        COORDINATOR = VRFCoordinatorV2Interface(vrfCoordinator);
        LINKTOKEN = LinkTokenInterface(link_token_contract);
        //Create a new subscription when you deploy the contract.
        createNewSubscription();
    }




//########################### Vrf Buy&Reborn Functions Start ####################
    

    /**
     * @dev  reborn NFT.
     * @param _ownerTokenId The NFT Id you want to reborn
     * @param _amountFeeMax max fee you want to pay for swapping
     * @param _deadline deadline
     * @param _gasLevel gas level you want pay for
     */
    function reborn(uint256 _ownerTokenId, uint256 _amountFeeMax, uint256 _deadline, uint8 _gasLevel) payable external ensure(_deadline)  nonReentrant vrfOpen {
        if (rebornMap[msg.sender] != 0) {
            revert ConcurrentRebornError(msg.sender, rebornMap[msg.sender]);
        }
        bytes32 keyHash = keyHash200;
        uint256 gasPrice = fixedGasPrice;
        if (_gasLevel == GAS_LEVEL_200) {
            gasPrice = 200 gwei;
        } else if (_gasLevel == GAS_LEVEL_500) {
            keyHash = keyHash500;
            gasPrice = 500 gwei;
        } else if (_gasLevel == GAS_LEVEL_1000) {
            keyHash = keyHash1000;
            gasPrice = 1000 gwei;
        }

        if(msg.value < gasPrice * rebornGas) {
            revert NoEnoughCallbackGas(msg.value, gasPrice * rebornGas);
        }
        if (msg.value > gasPrice * rebornGas) {
            payable(msg.sender).transfer(msg.value - gasPrice * rebornGas);
        }

        uint256 requestId = COORDINATOR.requestRandomWords(
          keyHash,
          subscriptionId,
          requestConfirmations,
          callbackGasLimit,
          numWords
        );
        RequestInfo storage reqInfo = reqInfos[requestId];
        reqInfo.reqFunc = REBRON_FUNC_TYPE;
        reqInfo.sender = msg.sender;
        reqInfo.ownerTokenId = _ownerTokenId;
        reqInfo.amountFeeMax = _amountFeeMax;
        reqInfo.deadline = _deadline;
        reqInfo.reqState = REQ_START;
        rebornMap[msg.sender] = requestId;

        uint256 _price = poolKit._currentPrice();
        uint256 feeValue = poolFeeValue + treasuryFeeValue;
        if (_amountFeeMax < _price * feeValue / FEE_BASE) {
            revert MaxFeeNotMatch(_amountFeeMax, _price * (FEE_BASE - feeValue) / FEE_BASE);
        }
        IERC20 _pandaToken = IERC20(pandaToken);
        if (_pandaToken.balanceOf(msg.sender) < _price *feeValue / FEE_BASE) {
            revert PandaNotEnough(msg.sender, _pandaToken.balanceOf(msg.sender), _price * feeValue / FEE_BASE);
        }
        if (poolFeeValue != 0) {
            poolKit._safeTransferFromPanda(msg.sender, address(poolKit), _price * poolFeeValue / FEE_BASE);
        }
        
        
        if(treasuryFeeValue != 0) {
            poolKit._safeTransferFromPanda(msg.sender, owner(), _price * treasuryFeeValue / FEE_BASE);
        }
        

        
        poolKit._safeTransferFromNFT(msg.sender, address(poolKit), _ownerTokenId, "");
        poolKit._poolPushNft(_ownerTokenId);

        emit PreReborn(requestId, msg.sender, _ownerTokenId, _price * feeValue / FEE_BASE);
    }


    /**
     * @dev buy NFT, you should pay $PANDA.
     * @param _amountBuyMax  Above this value you will not make a purchase
     * @param _deadline deadline
     * @param _gasLevel gas level you want pay for
     */
    function buy(uint256 _amountBuyMax, uint256 _deadline, uint8 _gasLevel) payable external ensure(_deadline)  nonReentrant vrfOpen {
        bytes32 keyHash = keyHash200;
        uint256 gasPrice = fixedGasPrice;
        if (_gasLevel == GAS_LEVEL_200) {
            gasPrice = 200 gwei;
        } else if (_gasLevel == GAS_LEVEL_500) {
            keyHash = keyHash500;
            gasPrice = 500 gwei;
        } else if (_gasLevel == GAS_LEVEL_1000) {
            keyHash = keyHash1000;
            gasPrice = 1000 gwei;
        }

        if(msg.value < gasPrice * buyGas) {
            revert NoEnoughCallbackGas(msg.value, gasPrice * buyGas);
        }
        if (msg.value > gasPrice * buyGas) {
            payable(msg.sender).transfer(msg.value - gasPrice * buyGas);
        } 

        uint256 requestId = COORDINATOR.requestRandomWords(
          keyHash,
          subscriptionId,
          requestConfirmations,
          callbackGasLimit,
          numWords
        );
        RequestInfo storage reqInfo = reqInfos[requestId];
        reqInfo.reqFunc = BUY_FUNC_TYPE;
        reqInfo.sender = msg.sender;
        reqInfo.amountFeeMax = _amountBuyMax;
        reqInfo.deadline = _deadline;
        reqInfo.reqState = REQ_START;
        buyMap[msg.sender] = requestId;

        uint256 feeValue = poolFeeValue + treasuryFeeValue;
        uint256 _price = poolKit._currentPrice();
        if (_amountBuyMax < _price * (FEE_BASE + feeValue) / FEE_BASE) {
            revert MaxBuyNotMatch(_amountBuyMax, _price * (FEE_BASE + feeValue) / FEE_BASE);
        }
        IERC20 _pandaToken = IERC20(pandaToken);
        if (_pandaToken.balanceOf(msg.sender) < _price * (FEE_BASE + feeValue) / FEE_BASE) {
            revert PandaNotEnough(msg.sender, _pandaToken.balanceOf(msg.sender), _price * (FEE_BASE + feeValue) / FEE_BASE);
        }

        if (poolFeeValue != 0) {
            poolKit._safeTransferFromPanda(msg.sender, address(poolKit), _price * (FEE_BASE + poolFeeValue) / FEE_BASE);
        }

        if (treasuryFeeValue != 0) {
            poolKit._safeTransferFromPanda(msg.sender,  owner(), _price * treasuryFeeValue/ FEE_BASE);
        }

        IERC721 _pandaNFT = IERC721(pandaNFT);
        if(_pandaNFT.balanceOf(address(poolKit)) <= poolKit._minPoolNFTCount()) {
            revert PoolNotEnoughNFT(_pandaNFT.balanceOf(address(poolKit)), poolKit._minPoolNFTCount());
        }
        
        emit PreBuy(requestId, msg.sender, _price * (FEE_BASE + feeValue) / FEE_BASE);
    }

    function fulfillRandomWords(
        uint256 _requestId, /* requestId */
        uint256[] memory randomWords
    ) internal override {
        uint256 index = randomWords[0] % poolKit._poolSize();
        uint256 targetIndex = poolKit._getIdByIndex(index);
        poolKit._poolRemoveNft(index);
        RequestInfo storage reqInfo = reqInfos[_requestId];
        reqInfo.targetTokenId = targetIndex;
        reqInfo.reqState = REQ_PENDING;
        emit RandomOpened(reqInfo.sender, index, targetIndex, _requestId, randomWords[0]);
        // uint256 funcType = reqInfo.reqFunc;
        // if (funcType == REBRON_FUNC_TYPE) {
        //     _reborn(reqInfo.sender,reqInfo.ownerTokenId, targetIndex, reqInfo.amountFeeMax, reqInfo.deadline);  
        // } else {
        //     _buy(reqInfo.sender, targetIndex, reqInfo.amountFeeMax, reqInfo.deadline);
        // }
    }

    /**
     * @dev external reborn NFT.
     */
    function onReborn() external  {
        uint256 _requestId = rebornMap[msg.sender];
        uint256 targetId = reqInfos[_requestId].targetTokenId;
        uint256 reqState = reqInfos[_requestId].reqState;
        if (_requestId == 0 || targetId == 0 || reqState != REQ_PENDING) {
            revert RequestInvalid(msg.sender, _requestId, targetId);
        }
        
        IERC721 _pandaNFT = IERC721(pandaNFT);
        if (_pandaNFT.ownerOf(targetId) != address(poolKit)) {
            revert NFTOwnerNotMatch(targetId, address(poolKit), _pandaNFT.ownerOf(targetId));
        }
        poolKit._safeTransferFromNFT(address(poolKit), msg.sender, targetId, "");
        rebornMap[msg.sender] = 0;
        reqInfos[_requestId].reqState = REQ_FINISH;
        emit Reborn(msg.sender, reqInfos[_requestId].ownerTokenId, targetId);
    }

    /**
     * @dev external buy NFT, you will receive $PANDA.
     */
    function onBuy() external {
        uint256 _requestId = buyMap[msg.sender];
        uint256 _targetId = reqInfos[_requestId].targetTokenId;
        uint256 _reqState = reqInfos[_requestId].reqState;
        if (_requestId == 0 || _targetId == 0 || _reqState != REQ_PENDING) {
            revert RequestInvalid(msg.sender, _requestId, _targetId);
        }
        IERC721 _pandaNFT = IERC721(pandaNFT);
        if (_pandaNFT.ownerOf(_targetId) != address(poolKit)) {
            revert NFTOwnerNotMatch(_targetId,  address(poolKit), _pandaNFT.ownerOf(_targetId));
        }
        poolKit._safeTransferFromNFT(address(poolKit), msg.sender, _targetId, "");

        buyMap[msg.sender] = 0;
        reqInfos[_requestId].reqState = REQ_FINISH;
        emit Buy(msg.sender, _targetId);
    }

    /**
     * @dev redeem NFT, you will receive $PANDA.
     * @param _ownerTokenId The NFT Id you want to redeem
     * @param _amountRedeemMin  Less than this value you will not redeem
     * @param _deadline deadline
     */
    function redeem(uint256 _ownerTokenId, uint256 _amountRedeemMin, uint256 _deadline) external ensure(_deadline) nonReentrant vrfOpen {
        IERC721 _pandaNFT = IERC721(pandaNFT);
        if (_pandaNFT.ownerOf(_ownerTokenId) != msg.sender) {
            revert NFTOwnerNotMatch(_ownerTokenId,  msg.sender, _pandaNFT.ownerOf(_ownerTokenId));
        }
        
        uint256 _price = poolKit._currentPrice();
        uint256 feeValue = poolFeeValue + treasuryFeeValue;
        if (_amountRedeemMin > _price * (FEE_BASE - feeValue) / FEE_BASE) {
            revert MinReceiveNotMatch(_amountRedeemMin, _price * (FEE_BASE - feeValue) / FEE_BASE);
        }

        poolKit._safeTransferFromNFT(msg.sender, address(poolKit), _ownerTokenId, "");
        poolKit._poolPushNft(_ownerTokenId);
        poolKit._safeTransferToPanda(msg.sender, _price * (FEE_BASE - feeValue) / FEE_BASE);
        emit Redeem(msg.sender, _ownerTokenId, _price * (FEE_BASE - feeValue) / FEE_BASE);
    }


//########################### Vrf Buy&Reborn Functions End ####################



//########################### VRF Base Functions Start ####################
    function createNewSubscription() public onlyOwner {
        address[] memory consumers = new address[](1);
        consumers[0] = address(this);
        subscriptionId = COORDINATOR.createSubscription();
        COORDINATOR.addConsumer(subscriptionId, consumers[0]);
        emit NewSubscription(consumers[0], subscriptionId);
    }

    function topUpSubscription(uint256 amount) external onlyOwner {
        LINKTOKEN.transferAndCall(address(COORDINATOR), amount, abi.encode(subscriptionId));
        emit TopUpSubscription(amount);
    }

    function addConsumer(address consumerAddress) external onlyOwner {
        COORDINATOR.addConsumer(subscriptionId, consumerAddress);
        emit AddConsumer(consumerAddress);
    }

    function removeConsumer(address consumerAddress) external onlyOwner {
        COORDINATOR.removeConsumer(subscriptionId, consumerAddress);
        emit RemoveConsumer(consumerAddress);
    }

    function cancelSubscription(address receivingWallet) external onlyOwner {
        COORDINATOR.cancelSubscription(subscriptionId, receivingWallet);
        subscriptionId = 0;
        emit CancelSubscription(receivingWallet, subscriptionId);
    }
//########################### VRF Base Functions End ####################



    /**
     * @dev withdrawERC20  tokens.
     * @param _recipient recipient
     * @param _tokenAddress  token
     * @param _tokenAmount amount
     */
    function withdrawERC20(address _recipient, address _tokenAddress, uint256 _tokenAmount) external onlyOwner notZeroAddr(_tokenAddress) {
        IERC20(_tokenAddress).safeTransfer(_recipient, _tokenAmount);
        emit WithdrawERC20(_recipient, _tokenAddress, _tokenAmount);
    }
    

    /**
     * @dev withdraw Ether.
     * @param recipient recipient
     * @param amount amount
     */
    function withdrawEther(address payable recipient, uint256 amount) external onlyOwner {
        (bool success,) = recipient.call{value:amount}("");
        if(!success) {
            revert TransferEhterFail(msg.sender, recipient, amount);
        }
        emit WithdrawEther(recipient, amount);
    }


    /**
     * @dev setLiquidityClose close or open swap、redeem、buy.
     * @param _vrfOpen true or false        
     */
    function setSwitchs(bool _vrfOpen) external onlyOwner {
        isVrfOpen = _vrfOpen;
        emit SwitchEvent(_vrfOpen);
    }

    function seteFixedGasPrice(uint256 _gasPrice) external onlyOwner {
        fixedGasPrice = _gasPrice;
        emit FixedGasPrice(_gasPrice);
    }

    function setCallbackGasLimet(uint32 _limit) external onlyOwner {
        callbackGasLimit = _limit;
        emit CallbackGasLimet(_limit);
    }

    function setPoolFeeValue(uint256 _feeValue) external onlyOwner {
        poolFeeValue = _feeValue;
        emit SetPoolFeeValue(_feeValue);
    }

    function setTreasuryFeeValue(uint256 _feeValue) external onlyOwner {
        treasuryFeeValue = _feeValue;
        emit SetTreasuryFeeValue(_feeValue);
    }


    fallback () external payable {}

    receive () external payable {}

}
// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/security/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// File: @openzeppelin/contracts/utils/cryptography/ECDSA.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/cryptography/ECDSA.sol)

pragma solidity ^0.8.0;

import "../Strings.sol";

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS,
        InvalidSignatureV
    }

    function _throwError(RecoverError error) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert("ECDSA: invalid signature");
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert("ECDSA: invalid signature length");
        } else if (error == RecoverError.InvalidSignatureS) {
            revert("ECDSA: invalid signature 's' value");
        } else if (error == RecoverError.InvalidSignatureV) {
            revert("ECDSA: invalid signature 'v' value");
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature` or error string. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     *
     * Documentation for signature generation:
     * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
     * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
        // Check the signature length
        // - case 65: r,s,v signature (standard)
        // - case 64: r,vs signature (cf https://eips.ethereum.org/EIPS/eip-2098) _Available since v4.1._
        if (signature.length == 65) {
            bytes32 r;
            bytes32 s;
            uint8 v;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            assembly {
                r := mload(add(signature, 0x20))
                s := mload(add(signature, 0x40))
                v := byte(0, mload(add(signature, 0x60)))
            }
            return tryRecover(hash, v, r, s);
        } else if (signature.length == 64) {
            bytes32 r;
            bytes32 vs;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            assembly {
                r := mload(add(signature, 0x20))
                vs := mload(add(signature, 0x40))
            }
            return tryRecover(hash, r, vs);
        } else {
            return (address(0), RecoverError.InvalidSignatureLength);
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, signature);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
     *
     * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        bytes32 r,
        bytes32 vs
    ) internal pure returns (address, RecoverError) {
        bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
        uint8 v = uint8((uint256(vs) >> 255) + 27);
        return tryRecover(hash, v, r, s);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
     *
     * _Available since v4.2._
     */
    function recover(
        bytes32 hash,
        bytes32 r,
        bytes32 vs
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, r, vs);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
     * `r` and `s` signature fields separately.
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address, RecoverError) {
        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return (address(0), RecoverError.InvalidSignatureS);
        }
        if (v != 27 && v != 28) {
            return (address(0), RecoverError.InvalidSignatureV);
        }

        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        if (signer == address(0)) {
            return (address(0), RecoverError.InvalidSignature);
        }

        return (signer, RecoverError.NoError);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function recover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, v, r, s);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from a `hash`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
        // 32 is the length in bytes of hash,
        // enforced by the type signature above
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from `s`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n", Strings.toString(s.length), s));
    }

    /**
     * @dev Returns an Ethereum Signed Typed Data, created from a
     * `domainSeparator` and a `structHash`. This produces hash corresponding
     * to the one signed with the
     * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
     * JSON-RPC method as part of EIP-712.
     *
     * See {recover}.
     */
    function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// File: @openzeppelin/contracts/token/ERC721/IERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}

// File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: @chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface LinkTokenInterface {
  function allowance(address owner, address spender) external view returns (uint256 remaining);

  function approve(address spender, uint256 value) external returns (bool success);

  function balanceOf(address owner) external view returns (uint256 balance);

  function decimals() external view returns (uint8 decimalPlaces);

  function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);

  function increaseApproval(address spender, uint256 subtractedValue) external;

  function name() external view returns (string memory tokenName);

  function symbol() external view returns (string memory tokenSymbol);

  function totalSupply() external view returns (uint256 totalTokensIssued);

  function transfer(address to, uint256 value) external returns (bool success);

  function transferAndCall(
    address to,
    uint256 value,
    bytes calldata data
  ) external returns (bool success);

  function transferFrom(
    address from,
    address to,
    uint256 value
  ) external returns (bool success);
}

// File: @chainlink/contracts/src/v0.8/interfaces/VRFCoordinatorV2Interface.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface VRFCoordinatorV2Interface {
  /**
   * @notice Get configuration relevant for making requests
   * @return minimumRequestConfirmations global min for request confirmations
   * @return maxGasLimit global max for request gas limit
   * @return s_provingKeyHashes list of registered key hashes
   */
  function getRequestConfig()
    external
    view
    returns (
      uint16,
      uint32,
      bytes32[] memory
    );

  /**
   * @notice Request a set of random words.
   * @param keyHash - Corresponds to a particular oracle job which uses
   * that key for generating the VRF proof. Different keyHash's have different gas price
   * ceilings, so you can select a specific one to bound your maximum per request cost.
   * @param subId  - The ID of the VRF subscription. Must be funded
   * with the minimum subscription balance required for the selected keyHash.
   * @param minimumRequestConfirmations - How many blocks you'd like the
   * oracle to wait before responding to the request. See SECURITY CONSIDERATIONS
   * for why you may want to request more. The acceptable range is
   * [minimumRequestBlockConfirmations, 200].
   * @param callbackGasLimit - How much gas you'd like to receive in your
   * fulfillRandomWords callback. Note that gasleft() inside fulfillRandomWords
   * may be slightly less than this amount because of gas used calling the function
   * (argument decoding etc.), so you may need to request slightly more than you expect
   * to have inside fulfillRandomWords. The acceptable range is
   * [0, maxGasLimit]
   * @param numWords - The number of uint256 random values you'd like to receive
   * in your fulfillRandomWords callback. Note these numbers are expanded in a
   * secure way by the VRFCoordinator from a single random value supplied by the oracle.
   * @return requestId - A unique identifier of the request. Can be used to match
   * a request to a response in fulfillRandomWords.
   */
  function requestRandomWords(
    bytes32 keyHash,
    uint64 subId,
    uint16 minimumRequestConfirmations,
    uint32 callbackGasLimit,
    uint32 numWords
  ) external returns (uint256 requestId);

  /**
   * @notice Create a VRF subscription.
   * @return subId - A unique subscription id.
   * @dev You can manage the consumer set dynamically with addConsumer/removeConsumer.
   * @dev Note to fund the subscription, use transferAndCall. For example
   * @dev  LINKTOKEN.transferAndCall(
   * @dev    address(COORDINATOR),
   * @dev    amount,
   * @dev    abi.encode(subId));
   */
  function createSubscription() external returns (uint64 subId);

  /**
   * @notice Get a VRF subscription.
   * @param subId - ID of the subscription
   * @return balance - LINK balance of the subscription in juels.
   * @return reqCount - number of requests for this subscription, determines fee tier.
   * @return owner - owner of the subscription.
   * @return consumers - list of consumer address which are able to use this subscription.
   */
  function getSubscription(uint64 subId)
    external
    view
    returns (
      uint96 balance,
      uint64 reqCount,
      address owner,
      address[] memory consumers
    );

  /**
   * @notice Request subscription owner transfer.
   * @param subId - ID of the subscription
   * @param newOwner - proposed new owner of the subscription
   */
  function requestSubscriptionOwnerTransfer(uint64 subId, address newOwner) external;

  /**
   * @notice Request subscription owner transfer.
   * @param subId - ID of the subscription
   * @dev will revert if original owner of subId has
   * not requested that msg.sender become the new owner.
   */
  function acceptSubscriptionOwnerTransfer(uint64 subId) external;

  /**
   * @notice Add a consumer to a VRF subscription.
   * @param subId - ID of the subscription
   * @param consumer - New consumer which can use the subscription
   */
  function addConsumer(uint64 subId, address consumer) external;

  /**
   * @notice Remove a consumer from a VRF subscription.
   * @param subId - ID of the subscription
   * @param consumer - Consumer to remove from the subscription
   */
  function removeConsumer(uint64 subId, address consumer) external;

  /**
   * @notice Cancel a subscription
   * @param subId - ID of the subscription
   * @param to - Where to send the remaining LINK to
   */
  function cancelSubscription(uint64 subId, address to) external;
}

// File: @chainlink/contracts/src/v0.8/VRFConsumerBaseV2.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

/** ****************************************************************************
 * @notice Interface for contracts using VRF randomness
 * *****************************************************************************
 * @dev PURPOSE
 *
 * @dev Reggie the Random Oracle (not his real job) wants to provide randomness
 * @dev to Vera the verifier in such a way that Vera can be sure he's not
 * @dev making his output up to suit himself. Reggie provides Vera a public key
 * @dev to which he knows the secret key. Each time Vera provides a seed to
 * @dev Reggie, he gives back a value which is computed completely
 * @dev deterministically from the seed and the secret key.
 *
 * @dev Reggie provides a proof by which Vera can verify that the output was
 * @dev correctly computed once Reggie tells it to her, but without that proof,
 * @dev the output is indistinguishable to her from a uniform random sample
 * @dev from the output space.
 *
 * @dev The purpose of this contract is to make it easy for unrelated contracts
 * @dev to talk to Vera the verifier about the work Reggie is doing, to provide
 * @dev simple access to a verifiable source of randomness. It ensures 2 things:
 * @dev 1. The fulfillment came from the VRFCoordinator
 * @dev 2. The consumer contract implements fulfillRandomWords.
 * *****************************************************************************
 * @dev USAGE
 *
 * @dev Calling contracts must inherit from VRFConsumerBase, and can
 * @dev initialize VRFConsumerBase's attributes in their constructor as
 * @dev shown:
 *
 * @dev   contract VRFConsumer {
 * @dev     constructor(<other arguments>, address _vrfCoordinator, address _link)
 * @dev       VRFConsumerBase(_vrfCoordinator) public {
 * @dev         <initialization with other arguments goes here>
 * @dev       }
 * @dev   }
 *
 * @dev The oracle will have given you an ID for the VRF keypair they have
 * @dev committed to (let's call it keyHash). Create subscription, fund it
 * @dev and your consumer contract as a consumer of it (see VRFCoordinatorInterface
 * @dev subscription management functions).
 * @dev Call requestRandomWords(keyHash, subId, minimumRequestConfirmations,
 * @dev callbackGasLimit, numWords),
 * @dev see (VRFCoordinatorInterface for a description of the arguments).
 *
 * @dev Once the VRFCoordinator has received and validated the oracle's response
 * @dev to your request, it will call your contract's fulfillRandomWords method.
 *
 * @dev The randomness argument to fulfillRandomWords is a set of random words
 * @dev generated from your requestId and the blockHash of the request.
 *
 * @dev If your contract could have concurrent requests open, you can use the
 * @dev requestId returned from requestRandomWords to track which response is associated
 * @dev with which randomness request.
 * @dev See "SECURITY CONSIDERATIONS" for principles to keep in mind,
 * @dev if your contract could have multiple requests in flight simultaneously.
 *
 * @dev Colliding `requestId`s are cryptographically impossible as long as seeds
 * @dev differ.
 *
 * *****************************************************************************
 * @dev SECURITY CONSIDERATIONS
 *
 * @dev A method with the ability to call your fulfillRandomness method directly
 * @dev could spoof a VRF response with any random value, so it's critical that
 * @dev it cannot be directly called by anything other than this base contract
 * @dev (specifically, by the VRFConsumerBase.rawFulfillRandomness method).
 *
 * @dev For your users to trust that your contract's random behavior is free
 * @dev from malicious interference, it's best if you can write it so that all
 * @dev behaviors implied by a VRF response are executed *during* your
 * @dev fulfillRandomness method. If your contract must store the response (or
 * @dev anything derived from it) and use it later, you must ensure that any
 * @dev user-significant behavior which depends on that stored value cannot be
 * @dev manipulated by a subsequent VRF request.
 *
 * @dev Similarly, both miners and the VRF oracle itself have some influence
 * @dev over the order in which VRF responses appear on the blockchain, so if
 * @dev your contract could have multiple VRF requests in flight simultaneously,
 * @dev you must ensure that the order in which the VRF responses arrive cannot
 * @dev be used to manipulate your contract's user-significant behavior.
 *
 * @dev Since the block hash of the block which contains the requestRandomness
 * @dev call is mixed into the input to the VRF *last*, a sufficiently powerful
 * @dev miner could, in principle, fork the blockchain to evict the block
 * @dev containing the request, forcing the request to be included in a
 * @dev different block with a different hash, and therefore a different input
 * @dev to the VRF. However, such an attack would incur a substantial economic
 * @dev cost. This cost scales with the number of blocks the VRF oracle waits
 * @dev until it calls responds to a request. It is for this reason that
 * @dev that you can signal to an oracle you'd like them to wait longer before
 * @dev responding to the request (however this is not enforced in the contract
 * @dev and so remains effective only in the case of unmodified oracle software).
 */
abstract contract VRFConsumerBaseV2 {
  error OnlyCoordinatorCanFulfill(address have, address want);
  address private immutable vrfCoordinator;

  /**
   * @param _vrfCoordinator address of VRFCoordinator contract
   */
  constructor(address _vrfCoordinator) {
    vrfCoordinator = _vrfCoordinator;
  }

  /**
   * @notice fulfillRandomness handles the VRF response. Your contract must
   * @notice implement it. See "SECURITY CONSIDERATIONS" above for important
   * @notice principles to keep in mind when implementing your fulfillRandomness
   * @notice method.
   *
   * @dev VRFConsumerBaseV2 expects its subcontracts to have a method with this
   * @dev signature, and will call it once it has verified the proof
   * @dev associated with the randomness. (It is triggered via a call to
   * @dev rawFulfillRandomness, below.)
   *
   * @param requestId The Id initially returned by requestRandomness
   * @param randomWords the VRF output expanded to the requested number of words
   */
  function fulfillRandomWords(uint256 requestId, uint256[] memory randomWords) internal virtual;

  // rawFulfillRandomness is called by VRFCoordinator when it receives a valid VRF
  // proof. rawFulfillRandomness then calls fulfillRandomness, after validating
  // the origin of the call
  function rawFulfillRandomWords(uint256 requestId, uint256[] memory randomWords) external {
    if (msg.sender != vrfCoordinator) {
      revert OnlyCoordinatorCanFulfill(msg.sender, vrfCoordinator);
    }
    fulfillRandomWords(requestId, randomWords);
  }
}

// File: contracts/interfaces/IPoolKit.sol



/*
 **                                                                                                                                                              
 **                                                                   dddddddd                                                                                   
 **  PPPPPPPPPPPPPPPPP                                                d::::::d                  DDDDDDDDDDDDD                  AAA                 OOOOOOOOO     
 **  P::::::::::::::::P                                               d::::::d                  D::::::::::::DDD              A:::A              OO:::::::::OO   
 **  P::::::PPPPPP:::::P                                              d::::::d                  D:::::::::::::::DD           A:::::A           OO:::::::::::::OO 
 **  PP:::::P     P:::::P                                             d:::::d                   DDD:::::DDDDD:::::D         A:::::::A         O:::::::OOO:::::::O
 **    P::::P     P:::::Paaaaaaaaaaaaa  nnnn  nnnnnnnn        ddddddddd:::::d   aaaaaaaaaaaaa     D:::::D    D:::::D       A:::::::::A        O::::::O   O::::::O
 **    P::::P     P:::::Pa::::::::::::a n:::nn::::::::nn    dd::::::::::::::d   a::::::::::::a    D:::::D     D:::::D     A:::::A:::::A       O:::::O     O:::::O
 **    P::::PPPPPP:::::P aaaaaaaaa:::::an::::::::::::::nn  d::::::::::::::::d   aaaaaaaaa:::::a   D:::::D     D:::::D    A:::::A A:::::A      O:::::O     O:::::O
 **    P:::::::::::::PP           a::::ann:::::::::::::::nd:::::::ddddd:::::d            a::::a   D:::::D     D:::::D   A:::::A   A:::::A     O:::::O     O:::::O
 **    P::::PPPPPPPPP      aaaaaaa:::::a  n:::::nnnn:::::nd::::::d    d:::::d     aaaaaaa:::::a   D:::::D     D:::::D  A:::::A     A:::::A    O:::::O     O:::::O
 **    P::::P            aa::::::::::::a  n::::n    n::::nd:::::d     d:::::d   aa::::::::::::a   D:::::D     D:::::D A:::::AAAAAAAAA:::::A   O:::::O     O:::::O
 **    P::::P           a::::aaaa::::::a  n::::n    n::::nd:::::d     d:::::d  a::::aaaa::::::a   D:::::D     D:::::DA:::::::::::::::::::::A  O:::::O     O:::::O
 **    P::::P          a::::a    a:::::a  n::::n    n::::nd:::::d     d:::::d a::::a    a:::::a   D:::::D    D:::::DA:::::AAAAAAAAAAAAA:::::A O::::::O   O::::::O
 **  PP::::::PP        a::::a    a:::::a  n::::n    n::::nd::::::ddddd::::::dda::::a    a:::::a DDD:::::DDDDD:::::DA:::::A             A:::::AO:::::::OOO:::::::O
 **  P::::::::P        a:::::aaaa::::::a  n::::n    n::::n d:::::::::::::::::da:::::aaaa::::::a D:::::::::::::::DDA:::::A               A:::::AOO:::::::::::::OO 
 **  P::::::::P         a::::::::::aa:::a n::::n    n::::n  d:::::::::ddd::::d a::::::::::aa:::aD::::::::::::DDD A:::::A                 A:::::A OO:::::::::OO   
 **  PPPPPPPPPP          aaaaaaaaaa  aaaa nnnnnn    nnnnnn   ddddddddd   ddddd  aaaaaaaaaa  aaaaDDDDDDDDDDDDD   AAAAAAA                   AAAAAAA  OOOOOOOOO     
 **  
*/
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.6;

interface IPoolKit {
    function _safeTransferPanda(address to, uint256 value) external;
    
    function _safeTransferFromPanda(address from, address to, uint256 value) external;

    function _safeTransferFromNFT(address from, address to, uint256 tokenId, bytes calldata data) external;

    function _poolSize() external view returns(uint256);

    function _poolRemoveNft(uint256 _index) external;

    function _poolPushNft(uint256 _value) external ;

    function _getIdByIndex(uint256 _index) external returns(uint256);

    function _currentPrice() external view returns(uint256 _price);

    function _minPoolNFTCount() external view returns(uint256);

    function _safeTransferToPanda(address to,uint256 value) external ;
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
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/utils/Strings.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        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);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    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);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed 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);
    }
}

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

// File: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    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");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    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");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    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);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    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);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    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);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}