// File: contracts/OpenSkyLoan.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;

import '@openzeppelin/contracts/access/Ownable.sol';
import '@openzeppelin/contracts/security/ReentrancyGuard.sol';
import '@openzeppelin/contracts/token/ERC20/IERC20.sol';
import '@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol';
import '@openzeppelin/contracts/token/ERC1155/IERC1155.sol';
import '@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol';
import '@openzeppelin/contracts/token/ERC721/utils/ERC721Holder.sol';

import '@openzeppelin/contracts/token/ERC1155/utils/ERC1155Holder.sol';
import '@openzeppelin/contracts/utils/Context.sol';
import '@openzeppelin/contracts/utils/Counters.sol';
import './interfaces/IOpenSkyFlashClaimReceiver.sol';
import './interfaces/IOpenSkyLoan.sol';
import './interfaces/IOpenSkySettings.sol';
import './interfaces/IACLManager.sol';
import './interfaces/IOpenSkyNFTDescriptor.sol';
import './libraries/types/DataTypes.sol';
import './libraries/math/WadRayMath.sol';
import './libraries/math/MathUtils.sol';
import './libraries/math/PercentageMath.sol';
import './libraries/helpers/Errors.sol';
import './interfaces/IOpenSkyIncentivesController.sol';

/**
 * @title OpenSkyLoan contract
 * @author OpenSky Labs
 * @notice Implementation of the loan NFT for the OpenSky protocol
 * @dev The functions about handling loan are callable by the OpenSkyPool contract defined also in the OpenSkySettings
 **/
contract OpenSkyLoan is Context, ERC721Enumerable, Ownable, ERC721Holder, ERC1155Holder, ReentrancyGuard, IOpenSkyLoan {
    using Counters for Counters.Counter;
    using PercentageMath for uint256;
    using SafeERC20 for IERC20;
    using WadRayMath for uint128;


    mapping(uint256 => DataTypes.LoanData) internal _loans;

    /// @inheritdoc IOpenSkyLoan
    mapping(address => mapping(uint256 => uint256)) public override getLoanId;

    uint256 public totalBorrows;

    mapping(address => uint256) public userBorrows;

    Counters.Counter private _tokenIdTracker;
    IOpenSkySettings public immutable SETTINGS;
    
    address internal _pool;

    modifier onlyPool(){
        require(_msgSender() == _pool, Errors.ACL_ONLY_POOL_CAN_CALL);
        _;
    }

    modifier onlyAirdropOperator() {
        IACLManager ACLManager = IACLManager(SETTINGS.ACLManagerAddress());
        require(ACLManager.isAirdropOperator(_msgSender()), Errors.ACL_ONLY_AIRDROP_OPERATOR_CAN_CALL);
        _;
    }

    modifier checkLoanExists(uint256 loanId) {
        require(_exists(loanId), Errors.LOAN_DOES_NOT_EXIST);
        _;
    }
    
    /**
     * @dev Constructor.
     * @param name The name of OpenSkyLoan NFT
     * @param symbol The symbol of OpenSkyLoan NFT
     * @param _settings The address of the OpenSkySettings contract
     */
    constructor(
        string memory name,
        string memory symbol,
        address _settings,
        address pool
    ) Ownable() ERC721(name, symbol) ReentrancyGuard() {
        SETTINGS = IOpenSkySettings(_settings);
        _pool = pool;
    }

    struct BorrowLocalVars {
        uint40 borrowBegin;
        uint40 overdueTime;
        uint40 liquidatableTime;
        uint40 extendableTime;
        uint256 interestPerSecond;
    }

    /// @inheritdoc IOpenSkyLoan
    function mint(
        uint256 reserveId,
        address borrower,
        address nftAddress,
        uint256 nftTokenId,
        uint256 amount,
        uint256 duration,
        uint256 borrowRate
    ) external override onlyPool returns (uint256 loanId, DataTypes.LoanData memory loan) {
        DataTypes.WhitelistInfo memory whitelistInfo = SETTINGS.getWhitelistDetail(reserveId, nftAddress);
        BorrowLocalVars memory vars;

        vars.borrowBegin = uint40(block.timestamp);
        vars.overdueTime = uint40(block.timestamp + duration);
        vars.liquidatableTime = uint40(block.timestamp + duration + whitelistInfo.overdueDuration);
        // add setting config
        vars.extendableTime = uint40(block.timestamp + duration - whitelistInfo.extendableDuration);

        vars.interestPerSecond = MathUtils.calculateBorrowInterestPerSecond(borrowRate, amount);

        loan = DataTypes.LoanData({
            reserveId: reserveId,
            nftAddress: nftAddress,
            tokenId: nftTokenId,
            borrower: borrower,
            amount: amount,
            borrowBegin: vars.borrowBegin,
            borrowDuration: uint40(duration),
            borrowOverdueTime: vars.overdueTime,
            liquidatableTime: vars.liquidatableTime,
            borrowRate: uint128(borrowRate),
            interestPerSecond: uint128(vars.interestPerSecond),
            extendableTime: vars.extendableTime,
            borrowEnd: 0,
            status: DataTypes.LoanStatus.BORROWING
        });
        loanId = _mint(loan, borrower);
        IERC721(loan.nftAddress).approve(_pool, loan.tokenId);

        getLoanId[nftAddress][nftTokenId] = loanId;
        emit Mint(loanId, borrower);
    }

    function _mint(DataTypes.LoanData memory loanData, address recipient) internal returns (uint256 tokenId) {
        _tokenIdTracker.increment();
        tokenId = _tokenIdTracker.current();
        _safeMint(recipient, tokenId);
        _loans[tokenId] = loanData;

        _triggerIncentive(loanData.borrower);

        totalBorrows = totalBorrows + loanData.amount;
        userBorrows[loanData.borrower] = userBorrows[loanData.borrower] + loanData.amount;
    }

    function _triggerIncentive(address borrower) internal {
        address incentiveControllerAddress = SETTINGS.incentiveControllerAddress();
        if (incentiveControllerAddress != address(0)) {
            IOpenSkyIncentivesController incentivesController = IOpenSkyIncentivesController(
                incentiveControllerAddress
            );
            incentivesController.handleAction(borrower, userBorrows[borrower], totalBorrows);
        }
    }

    /// @inheritdoc IOpenSkyLoan
    function startLiquidation(uint256 tokenId) external override onlyPool checkLoanExists(tokenId) {
        _updateStatus(tokenId, DataTypes.LoanStatus.LIQUIDATING);
        _loans[tokenId].borrowEnd = uint40(block.timestamp);

        address owner = ownerOf(tokenId);
        _triggerIncentive(owner);

        userBorrows[owner] = userBorrows[owner] - _loans[tokenId].amount;
        totalBorrows = totalBorrows - _loans[tokenId].amount;

        emit StartLiquidation(tokenId, _msgSender());
    }

    /// @inheritdoc IOpenSkyLoan
    function endLiquidation(uint256 tokenId) external override onlyPool checkLoanExists(tokenId) {
        _burn(tokenId);

        delete getLoanId[_loans[tokenId].nftAddress][_loans[tokenId].tokenId];
        delete _loans[tokenId];

        emit EndLiquidation(tokenId, _msgSender());
    }

    /// @inheritdoc IOpenSkyLoan
    function end(
        uint256 tokenId,
        address onBehalfOf,
        address repayer
    ) external override onlyPool checkLoanExists(tokenId) {
        require(ownerOf(tokenId) == onBehalfOf, Errors.LOAN_REPAYER_IS_NOT_OWNER);

        if (_loans[tokenId].status != DataTypes.LoanStatus.LIQUIDATING) {
            address owner = ownerOf(tokenId);
            _triggerIncentive(owner);

            userBorrows[owner] = userBorrows[owner] - _loans[tokenId].amount;
            totalBorrows = totalBorrows - _loans[tokenId].amount;
        }

        _burn(tokenId);

        delete getLoanId[_loans[tokenId].nftAddress][_loans[tokenId].tokenId];
        delete _loans[tokenId];

        emit End(tokenId, onBehalfOf, repayer);
    }

    /**
     * @notice Updates the status of a loan.
     * @param tokenId The id of the loan
     * @param status The status of the loan will be set
     **/
    function _updateStatus(uint256 tokenId, DataTypes.LoanStatus status) internal {
        DataTypes.LoanData storage loanData = _loans[tokenId];
        require(loanData.status != DataTypes.LoanStatus.LIQUIDATING, Errors.LOAN_LIQUIDATING_STATUS_CAN_NOT_BE_UPDATED);
        require(loanData.status != status, Errors.LOAN_SET_STATUS_ERROR);
        loanData.status = status;
        emit UpdateStatus(tokenId, status);
    }

    /**
     * @notice Transfers the loan between two users. Calls the function of the incentives controller contract.
     * @param from The source address
     * @param to The destination address
     * @param tokenId The id of the loan
     **/
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual override {
        super._transfer(from, to, tokenId);

        DataTypes.LoanStatus status = getStatus(tokenId);
        if (status == DataTypes.LoanStatus.BORROWING || status == DataTypes.LoanStatus.EXTENDABLE) {
            address incentiveControllerAddress = SETTINGS.incentiveControllerAddress();
            DataTypes.LoanData memory loanData = _loans[tokenId];
            if (incentiveControllerAddress != address(0)) {
                IOpenSkyIncentivesController incentivesController = IOpenSkyIncentivesController(
                    incentiveControllerAddress
                );
                incentivesController.handleAction(from, userBorrows[from], totalBorrows);
                if (from != to) {
                    incentivesController.handleAction(to, userBorrows[to], totalBorrows);
                }
            }
            userBorrows[from] = userBorrows[from] - loanData.amount;
            userBorrows[to] = userBorrows[to] + loanData.amount;
        }
    }

    /// @inheritdoc IOpenSkyLoan
    function getLoanData(uint256 tokenId) external view override checkLoanExists(tokenId) returns (DataTypes.LoanData memory) {
        DataTypes.LoanData memory loan = _loans[tokenId];
        loan.status = getStatus(tokenId);
        return loan;
    }

    /// @inheritdoc IOpenSkyLoan
    function getBorrowInterest(uint256 tokenId) public view override checkLoanExists(tokenId) returns (uint256) {
        DataTypes.LoanData memory loan = _loans[tokenId];
        uint256 endTime = loan.borrowEnd > 0 ? loan.borrowEnd : block.timestamp;
        return loan.interestPerSecond.rayMul(endTime - loan.borrowBegin);
    }

    /// @inheritdoc IOpenSkyLoan
    function getStatus(uint256 tokenId) public view override checkLoanExists(tokenId) returns (DataTypes.LoanStatus) {
        DataTypes.LoanData memory loan = _loans[tokenId];
        DataTypes.LoanStatus status = _loans[tokenId].status;
        if (status == DataTypes.LoanStatus.BORROWING) {
            if (loan.liquidatableTime < block.timestamp) {
                status = DataTypes.LoanStatus.LIQUIDATABLE;
            } else if (loan.borrowOverdueTime < block.timestamp) {
                status = DataTypes.LoanStatus.OVERDUE;
            } else if (loan.extendableTime < block.timestamp) {
                status = DataTypes.LoanStatus.EXTENDABLE;
            }
        }
        return status;
    }

    /// @inheritdoc IOpenSkyLoan
    function getBorrowBalance(uint256 tokenId) external view override checkLoanExists(tokenId) returns (uint256) {
        return _loans[tokenId].amount + getBorrowInterest(tokenId);
    }

    /// @inheritdoc IOpenSkyLoan
    function getPenalty(uint256 tokenId) external view override checkLoanExists(tokenId) returns (uint256) {
        DataTypes.LoanStatus status = getStatus(tokenId);
        DataTypes.LoanData memory loan = _loans[tokenId];
        uint256 penalty = 0;
        if (status == DataTypes.LoanStatus.BORROWING) {
            penalty = loan.amount.percentMul(SETTINGS.prepaymentFeeFactor());
        } else if (status == DataTypes.LoanStatus.OVERDUE) {
            penalty = loan.amount.percentMul(SETTINGS.overdueLoanFeeFactor());
        }
        return penalty;
    }

    /// @inheritdoc IOpenSkyLoan
    function flashClaim(
        address receiverAddress,
        uint256[] calldata loanIds,
        bytes calldata params
    ) external override nonReentrant {
        uint256 i;
        IOpenSkyFlashClaimReceiver receiver = IOpenSkyFlashClaimReceiver(receiverAddress);
        // !!!CAUTION: receiver contract may reentry mint, burn, flashclaim again

        // only loan owner can do flashclaim
        address[] memory nftAddresses = new address[](loanIds.length);
        uint256[] memory tokenIds = new uint256[](loanIds.length);
        for (i = 0; i < loanIds.length; i++) {
            require(ownerOf(loanIds[i]) == _msgSender(), Errors.LOAN_CALLER_IS_NOT_OWNER);
            DataTypes.LoanStatus status = getStatus(loanIds[i]);
            require(
                status != DataTypes.LoanStatus.LIQUIDATABLE && status != DataTypes.LoanStatus.LIQUIDATING,
                Errors.FLASHCLAIM_STATUS_ERROR
            );
            DataTypes.LoanData memory loan = _loans[loanIds[i]];
            nftAddresses[i] = loan.nftAddress;
            tokenIds[i] = loan.tokenId;
        }

        // step 1: moving underlying asset forward to receiver contract
        for (i = 0; i < loanIds.length; i++) {
            IERC721(nftAddresses[i]).safeTransferFrom(address(this), receiverAddress, tokenIds[i]);
        }

        // setup 2: execute receiver contract, doing something like airdrop
        require(
            receiver.executeOperation(nftAddresses, tokenIds, _msgSender(), address(this), params),
            Errors.FLASHCLAIM_EXECUTOR_ERROR
        );

        // setup 3: moving underlying asset backward from receiver contract
        for (i = 0; i < loanIds.length; i++) {
            IERC721(nftAddresses[i]).safeTransferFrom(receiverAddress, address(this), tokenIds[i]);
            emit FlashClaim(receiverAddress, _msgSender(), nftAddresses[i], tokenIds[i]);
        }
    }

    /// @inheritdoc IOpenSkyLoan
    function claimERC20Airdrop(
        address token,
        address to,
        uint256 amount
    ) external override onlyAirdropOperator {
        // make sure that params are checked in admin contract
        IERC20(token).safeTransfer(to, amount);
        emit ClaimERC20Airdrop(token, to, amount);
    }

    /// @inheritdoc IOpenSkyLoan
    function claimERC721Airdrop(
        address token,
        address to,
        uint256[] calldata ids
    ) external override onlyAirdropOperator {
        // make sure that params are checked in admin contract
        for (uint256 i = 0; i < ids.length; i++) {
            require(getLoanId[token][ids[i]] == 0, Errors.LOAN_COLLATERAL_NFT_CAN_NOT_BE_CLAIMED);
            IERC721(token).safeTransferFrom(address(this), to, ids[i]);
        }
        emit ClaimERC721Airdrop(token, to, ids);
    }

    /// @inheritdoc IOpenSkyLoan
    function claimERC1155Airdrop(
        address token,
        address to,
        uint256[] calldata ids,
        uint256[] calldata amounts,
        bytes calldata data
    ) external override onlyAirdropOperator {
        // make sure that params are checked in admin contract
        IERC1155(token).safeBatchTransferFrom(address(this), to, ids, amounts, data);
        emit ClaimERC1155Airdrop(token, to, ids, amounts, data);
    }

    function supportsInterface(bytes4 interfaceId)
        public
        view
        virtual
        override(ERC1155Receiver, IERC165, ERC721Enumerable)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }

    function tokenURI(uint256 tokenId) public view override returns (string memory) {
        if (SETTINGS.loanDescriptorAddress() != address(0)) {
            return IOpenSkyNFTDescriptor(SETTINGS.loanDescriptorAddress()).tokenURI(tokenId);
        } else {
            return '';
        }
    }
}

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



// SPDX-License-Identifier: MIT

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() {
        _setOwner(_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 {
        _setOwner(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");
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

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



// SPDX-License-Identifier: MIT

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 make 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/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, 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 `sender` to `recipient` 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 sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @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);
}

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



// SPDX-License-Identifier: MIT

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: @openzeppelin/contracts/token/ERC1155/IERC1155.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

/**
 * @dev Required interface of an ERC1155 compliant contract, as defined in the
 * https://eips.ethereum.org/EIPS/eip-1155[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155 is IERC165 {
    /**
     * @dev Emitted when `value` tokens of token type `id` are transferred from `from` to `to` by `operator`.
     */
    event TransferSingle(address indexed operator, address indexed from, address indexed to, uint256 id, uint256 value);

    /**
     * @dev Equivalent to multiple {TransferSingle} events, where `operator`, `from` and `to` are the same for all
     * transfers.
     */
    event TransferBatch(
        address indexed operator,
        address indexed from,
        address indexed to,
        uint256[] ids,
        uint256[] values
    );

    /**
     * @dev Emitted when `account` grants or revokes permission to `operator` to transfer their tokens, according to
     * `approved`.
     */
    event ApprovalForAll(address indexed account, address indexed operator, bool approved);

    /**
     * @dev Emitted when the URI for token type `id` changes to `value`, if it is a non-programmatic URI.
     *
     * If an {URI} event was emitted for `id`, the standard
     * https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[guarantees] that `value` will equal the value
     * returned by {IERC1155MetadataURI-uri}.
     */
    event URI(string value, uint256 indexed id);

    /**
     * @dev Returns the amount of tokens of token type `id` owned by `account`.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function balanceOf(address account, uint256 id) external view returns (uint256);

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {balanceOf}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(address[] calldata accounts, uint256[] calldata ids)
        external
        view
        returns (uint256[] memory);

    /**
     * @dev Grants or revokes permission to `operator` to transfer the caller's tokens, according to `approved`,
     *
     * Emits an {ApprovalForAll} event.
     *
     * Requirements:
     *
     * - `operator` cannot be the caller.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns true if `operator` is approved to transfer ``account``'s tokens.
     *
     * See {setApprovalForAll}.
     */
    function isApprovedForAll(address account, address operator) external view returns (bool);

    /**
     * @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If the caller is not `from`, it must be have been approved to spend ``from``'s tokens via {setApprovalForAll}.
     * - `from` must have a balance of tokens of type `id` of at least `amount`.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes calldata data
    ) external;

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {safeTransferFrom}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] calldata ids,
        uint256[] calldata amounts,
        bytes calldata data
    ) external;
}

// File: @openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../ERC721.sol";
import "./IERC721Enumerable.sol";

/**
 * @dev This implements an optional extension of {ERC721} defined in the EIP that adds
 * enumerability of all the token ids in the contract as well as all token ids owned by each
 * account.
 */
abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
    // Mapping from owner to list of owned token IDs
    mapping(address => mapping(uint256 => uint256)) private _ownedTokens;

    // Mapping from token ID to index of the owner tokens list
    mapping(uint256 => uint256) private _ownedTokensIndex;

    // Array with all token ids, used for enumeration
    uint256[] private _allTokens;

    // Mapping from token id to position in the allTokens array
    mapping(uint256 => uint256) private _allTokensIndex;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
        return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     */
    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];
    }

    /**
     * @dev See {IERC721Enumerable-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _allTokens.length;
    }

    /**
     * @dev See {IERC721Enumerable-tokenByIndex}.
     */
    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721Enumerable.totalSupply(), "ERC721Enumerable: global index out of bounds");
        return _allTokens[index];
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    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);
        }
    }

    /**
     * @dev Private function to add a token to this extension's ownership-tracking data structures.
     * @param to address representing the new owner of the given token ID
     * @param tokenId uint256 ID of the token to be added to the tokens list of the given address
     */
    function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
        uint256 length = ERC721.balanceOf(to);
        _ownedTokens[to][length] = tokenId;
        _ownedTokensIndex[tokenId] = length;
    }

    /**
     * @dev Private function to add a token to this extension's token tracking data structures.
     * @param tokenId uint256 ID of the token to be added to the tokens list
     */
    function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
        _allTokensIndex[tokenId] = _allTokens.length;
        _allTokens.push(tokenId);
    }

    /**
     * @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that
     * while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for
     * gas optimizations e.g. when performing a transfer operation (avoiding double writes).
     * This has O(1) time complexity, but alters the order of the _ownedTokens array.
     * @param from address representing the previous owner of the given token ID
     * @param tokenId uint256 ID of the token to be removed from the tokens list of the given address
     */
    function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {
        // To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).

        uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;
        uint256 tokenIndex = _ownedTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary
        if (tokenIndex != lastTokenIndex) {
            uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];

            _ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
            _ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
        }

        // This also deletes the contents at the last position of the array
        delete _ownedTokensIndex[tokenId];
        delete _ownedTokens[from][lastTokenIndex];
    }

    /**
     * @dev Private function to remove a token from this extension's token tracking data structures.
     * This has O(1) time complexity, but alters the order of the _allTokens array.
     * @param tokenId uint256 ID of the token to be removed from the tokens list
     */
    function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {
        // To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).

        uint256 lastTokenIndex = _allTokens.length - 1;
        uint256 tokenIndex = _allTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so
        // rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding
        // an 'if' statement (like in _removeTokenFromOwnerEnumeration)
        uint256 lastTokenId = _allTokens[lastTokenIndex];

        _allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
        _allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index

        // This also deletes the contents at the last position of the array
        delete _allTokensIndex[tokenId];
        _allTokens.pop();
    }
}

// File: @openzeppelin/contracts/token/ERC721/utils/ERC721Holder.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC721Receiver.sol";

/**
 * @dev Implementation of the {IERC721Receiver} interface.
 *
 * Accepts all token transfers.
 * Make sure the contract is able to use its token with {IERC721-safeTransferFrom}, {IERC721-approve} or {IERC721-setApprovalForAll}.
 */
contract ERC721Holder is IERC721Receiver {
    /**
     * @dev See {IERC721Receiver-onERC721Received}.
     *
     * Always returns `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address,
        address,
        uint256,
        bytes memory
    ) public virtual override returns (bytes4) {
        return this.onERC721Received.selector;
    }
}

// File: @openzeppelin/contracts/token/ERC1155/utils/ERC1155Holder.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./ERC1155Receiver.sol";

/**
 * @dev _Available since v3.1._
 */
contract ERC1155Holder is ERC1155Receiver {
    function onERC1155Received(
        address,
        address,
        uint256,
        uint256,
        bytes memory
    ) public virtual override returns (bytes4) {
        return this.onERC1155Received.selector;
    }

    function onERC1155BatchReceived(
        address,
        address,
        uint256[] memory,
        uint256[] memory,
        bytes memory
    ) public virtual override returns (bytes4) {
        return this.onERC1155BatchReceived.selector;
    }
}

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



// SPDX-License-Identifier: MIT

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/Counters.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @title Counters
 * @author Matt Condon (@shrugs)
 * @dev Provides counters that can only be incremented, decremented or reset. This can be used e.g. to track the number
 * of elements in a mapping, issuing ERC721 ids, or counting request ids.
 *
 * Include with `using Counters for Counters.Counter;`
 */
library Counters {
    struct Counter {
        // This variable should never be directly accessed by users of the library: interactions must be restricted to
        // the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
        // this feature: see https://github.com/ethereum/solidity/issues/4637
        uint256 _value; // default: 0
    }

    function current(Counter storage counter) internal view returns (uint256) {
        return counter._value;
    }

    function increment(Counter storage counter) internal {
        unchecked {
            counter._value += 1;
        }
    }

    function decrement(Counter storage counter) internal {
        uint256 value = counter._value;
        require(value > 0, "Counter: decrement overflow");
        unchecked {
            counter._value = value - 1;
        }
    }

    function reset(Counter storage counter) internal {
        counter._value = 0;
    }
}

// File: contracts/interfaces/IOpenSkyFlashClaimReceiver.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;

interface IOpenSkyFlashClaimReceiver {
    function executeOperation(
        address[] calldata nftAddresses,
        uint256[] calldata tokenIds,
        address initiator,
        address operator,
        bytes calldata params
    ) external returns (bool);
}

// File: contracts/interfaces/IOpenSkyLoan.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;

import '@openzeppelin/contracts/token/ERC721/IERC721.sol';
import '../libraries/types/DataTypes.sol';

/**
 * @title IOpenSkyLoan
 * @author OpenSky Labs
 * @notice Defines the basic interface for OpenSkyLoan.  This loan NFT is composable and can be used in other DeFi protocols 
 **/
interface IOpenSkyLoan is IERC721 {

    /**
     * @dev Emitted on mint()
     * @param tokenId The ID of the loan
     * @param recipient The address that will receive the loan NFT
     **/
    event Mint(uint256 indexed tokenId, address indexed recipient);

    /**
     * @dev Emitted on end()
     * @param tokenId The ID of the loan
     * @param onBehalfOf The address the repayer is repaying for
     * @param repayer The address of the user initiating the repayment()
     **/
    event End(uint256 indexed tokenId, address indexed onBehalfOf, address indexed repayer);

    /**
     * @dev Emitted on startLiquidation()
     * @param tokenId The ID of the loan
     * @param liquidator The address of the liquidator
     **/
    event StartLiquidation(uint256 indexed tokenId, address indexed liquidator);

    /**
     * @dev Emitted on endLiquidation()
     * @param tokenId The ID of the loan
     * @param liquidator The address of the liquidator
     **/
    event EndLiquidation(uint256 indexed tokenId, address indexed liquidator);

    /**
     * @dev Emitted on updateStatus()
     * @param tokenId The ID of the loan
     * @param status The status of loan
     **/
    event UpdateStatus(uint256 indexed tokenId, DataTypes.LoanStatus indexed status);

    /**
     * @dev Emitted on flashClaim()
     * @param receiver The address of the flash loan receiver contract
     * @param sender The address that will receive tokens
     * @param nftAddress The address of the collateralized NFT
     * @param tokenId The ID of collateralized NFT
     **/
    event FlashClaim(address indexed receiver, address sender, address indexed nftAddress, uint256 indexed tokenId);

    /**
     * @dev Emitted on claimERC20Airdrop()
     * @param token The address of the ERC20 token
     * @param to The address that will receive the ERC20 tokens
     * @param amount The amount of the tokens
     **/
    event ClaimERC20Airdrop(address indexed token, address indexed to, uint256 amount);

    /**
     * @dev Emitted on claimERC721Airdrop()
     * @param token The address of ERC721 token
     * @param to The address that will receive the eRC721 tokens
     * @param ids The ID of the token
     **/
    event ClaimERC721Airdrop(address indexed token, address indexed to, uint256[] ids);

    /**
     * @dev Emitted on claimERC1155Airdrop()
     * @param token The address of the ERC1155 token
     * @param to The address that will receive the ERC1155 tokens
     * @param ids The ID of the token
     * @param amounts The amount of the tokens
     * @param data packed params to pass to the receiver as extra information
     **/
    event ClaimERC1155Airdrop(address indexed token, address indexed to, uint256[] ids, uint256[] amounts, bytes data);

    /**
     * @notice Mints a loan NFT to user
     * @param reserveId The ID of the reserve
     * @param borrower The address of the borrower
     * @param nftAddress The contract address of the collateralized NFT 
     * @param nftTokenId The ID of the collateralized NFT
     * @param amount The amount of the loan
     * @param duration The duration of the loan
     * @param borrowRate The borrow rate of the loan
     * @return loanId and loan data
     **/
    function mint(
        uint256 reserveId,
        address borrower,
        address nftAddress,
        uint256 nftTokenId,
        uint256 amount,
        uint256 duration,
        uint256 borrowRate
    ) external returns (uint256 loanId, DataTypes.LoanData memory loan);

    /**
     * @notice Starts liquidation of the loan in default
     * @param tokenId The ID of the defaulted loan
     **/
    function startLiquidation(uint256 tokenId) external;

    /**
     * @notice Ends liquidation of a loan that is fully settled
     * @param tokenId The ID of the loan
     **/
    function endLiquidation(uint256 tokenId) external;

    /**
     * @notice Terminates the loan
     * @param tokenId The ID of the loan
     * @param onBehalfOf The address the repayer is repaying for
     * @param repayer The address of the repayer
     **/
    function end(uint256 tokenId, address onBehalfOf, address repayer) external;
    
    /**
     * @notice Returns the loan data
     * @param tokenId The ID of the loan
     * @return The details of the loan
     **/
    function getLoanData(uint256 tokenId) external view returns (DataTypes.LoanData calldata);

    /**
     * @notice Returns the status of a loan
     * @param tokenId The ID of the loan
     * @return The status of the loan
     **/
    function getStatus(uint256 tokenId) external view returns (DataTypes.LoanStatus);

    /**
     * @notice Returns the borrow interest of the loan
     * @param tokenId The ID of the loan
     * @return The borrow interest of the loan
     **/
    function getBorrowInterest(uint256 tokenId) external view returns (uint256);

    /**
     * @notice Returns the borrow balance of a loan, including borrow interest
     * @param tokenId The ID of the loan
     * @return The borrow balance of the loan
     **/
    function getBorrowBalance(uint256 tokenId) external view returns (uint256);

    /**
     * @notice Returns the penalty fee of the loan
     * @param tokenId The ID of the loan
     * @return The penalty fee of the loan
     **/
    function getPenalty(uint256 tokenId) external view returns (uint256);

    /**
     * @notice Returns the ID of the loan
     * @param nftAddress The address of the collateralized NFT
     * @param tokenId The ID of the collateralized NFT
     * @return The ID of the loan
     **/
    function getLoanId(address nftAddress, uint256 tokenId) external view returns (uint256);

    /**
     * @notice Allows smart contracts to access the collateralized NFT within one transaction,
     * as long as the amount taken plus a fee is returned
     * @dev IMPORTANT There are security concerns for developers of flash loan receiver contracts that must be carefully considered
     * @param receiverAddress The address of the contract receiving the funds, implementing IOpenSkyFlashClaimReceiver interface
     * @param loanIds The ID of loan being flash-borrowed
     * @param params packed params to pass to the receiver as extra information
     **/
    function flashClaim(
        address receiverAddress,
        uint256[] calldata loanIds,
        bytes calldata params
    ) external;

    /**
     * @notice Claim the ERC20 token which has been airdropped to the loan contract
     * @param token The address of the airdropped token
     * @param to The address which will receive ERC20 token
     * @param amount The amount of the ERC20 token
     **/
    function claimERC20Airdrop(
        address token,
        address to,
        uint256 amount
    ) external;

    /**
     * @notice Claim the ERC721 token which has been airdropped to the loan contract
     * @param token The address of the airdropped token
     * @param to The address which will receive the ERC721 token
     * @param ids The ID of the ERC721 token
     **/
    function claimERC721Airdrop(
        address token,
        address to,
        uint256[] calldata ids
    ) external;

    /**
     * @notice Claim the ERC1155 token which has been airdropped to the loan contract
     * @param token The address of the airdropped token
     * @param to The address which will receive the ERC1155 tokens
     * @param ids The ID of the ERC1155 token
     * @param amounts The amount of the ERC1155 tokens
     * @param data packed params to pass to the receiver as extra information
     **/
    function claimERC1155Airdrop(
        address token,
        address to,
        uint256[] calldata ids,
        uint256[] calldata amounts,
        bytes calldata data
    ) external;
}

// File: contracts/interfaces/IOpenSkySettings.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;
import '../libraries/types/DataTypes.sol';

interface IOpenSkySettings {
    event InitPoolAddress(address operator, address address_);
    event InitLoanAddress(address operator, address address_);
    event InitVaultFactoryAddress(address operator, address address_);
    event InitIncentiveControllerAddress(address operator, address address_);
    event InitWETHGatewayAddress(address operator, address address_);
    event InitPunkGatewayAddress(address operator, address address_);
    event InitDaoVaultAddress(address operator, address address_);

    event AddToWhitelist(address operator, uint256 reserveId, address nft);
    event RemoveFromWhitelist(address operator, uint256 reserveId, address nft);
    event SetReserveFactor(address operator, uint256 factor);
    event SetPrepaymentFeeFactor(address operator, uint256 factor);
    event SetOverdueLoanFeeFactor(address operator, uint256 factor);
    event SetMoneyMarketAddress(address operator, address address_);
    event SetTreasuryAddress(address operator, address address_);
    event SetACLManagerAddress(address operator, address address_);
    event SetLoanDescriptorAddress(address operator, address address_);
    event SetNftPriceOracleAddress(address operator, address address_);
    event SetInterestRateStrategyAddress(address operator, address address_);
    event AddLiquidator(address operator, address address_);
    event RemoveLiquidator(address operator, address address_);

    function poolAddress() external view returns (address);

    function loanAddress() external view returns (address);

    function vaultFactoryAddress() external view returns (address);

    function incentiveControllerAddress() external view returns (address);

    function wethGatewayAddress() external view returns (address);

    function punkGatewayAddress() external view returns (address);

    function inWhitelist(uint256 reserveId, address nft) external view returns (bool);

    function getWhitelistDetail(uint256 reserveId, address nft) external view returns (DataTypes.WhitelistInfo memory);

    function reserveFactor() external view returns (uint256); // treasury ratio

    function MAX_RESERVE_FACTOR() external view returns (uint256);

    function prepaymentFeeFactor() external view returns (uint256);

    function overdueLoanFeeFactor() external view returns (uint256);

    function moneyMarketAddress() external view returns (address);

    function treasuryAddress() external view returns (address);

    function daoVaultAddress() external view returns (address);

    function ACLManagerAddress() external view returns (address);

    function loanDescriptorAddress() external view returns (address);

    function nftPriceOracleAddress() external view returns (address);

    function interestRateStrategyAddress() external view returns (address);
    
    function isLiquidator(address liquidator) external view returns (bool);
}

// File: contracts/interfaces/IACLManager.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;

interface IACLManager {
    function addEmergencyAdmin(address admin) external;
    
    function isEmergencyAdmin(address admin) external view returns (bool);
    
    function removeEmergencyAdmin(address admin) external;
    
    function addGovernance(address admin) external;
    
    function isGovernance(address admin) external view returns (bool);

    function removeGovernance(address admin) external;

    function addPoolAdmin(address admin) external;

    function isPoolAdmin(address admin) external view returns (bool);

    function removePoolAdmin(address admin) external;

    function addLiquidationOperator(address address_) external;

    function isLiquidationOperator(address address_) external view returns (bool);

    function removeLiquidationOperator(address address_) external;

    function addAirdropOperator(address address_) external;

    function isAirdropOperator(address address_) external view returns (bool);

    function removeAirdropOperator(address address_) external;
}

// File: contracts/interfaces/IOpenSkyNFTDescriptor.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;

interface IOpenSkyNFTDescriptor {
    function tokenURI(uint256 reserveId)
        external
        view
        returns (string memory);
}

// File: contracts/libraries/types/DataTypes.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;

library DataTypes {
    struct ReserveData {
        uint256 reserveId;
        address underlyingAsset;
        address oTokenAddress;
        address moneyMarketAddress;
        uint128 lastSupplyIndex;
        uint256 borrowingInterestPerSecond;
        uint256 lastMoneyMarketBalance;
        uint40 lastUpdateTimestamp;
        uint256 totalBorrows;
        address interestModelAddress;
        uint256 treasuryFactor;
        bool isMoneyMarketOn;
    }

    struct LoanData {
        uint256 reserveId;
        address nftAddress;
        uint256 tokenId;
        address borrower;
        uint256 amount;
        uint128 borrowRate;
        uint128 interestPerSecond;
        uint40 borrowBegin;
        uint40 borrowDuration;
        uint40 borrowOverdueTime;
        uint40 liquidatableTime;
        uint40 extendableTime;
        uint40 borrowEnd;
        LoanStatus status;
    }

    enum LoanStatus {
        NONE,
        BORROWING,
        EXTENDABLE,
        OVERDUE,
        LIQUIDATABLE,
        LIQUIDATING
    }

    struct WhitelistInfo {
        bool enabled;
        string name;
        string symbol;
        uint256 LTV;
        uint256 minBorrowDuration;
        uint256 maxBorrowDuration;
        uint256 extendableDuration;
        uint256 overdueDuration;
    }
}

// File: contracts/libraries/math/WadRayMath.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;

import {Errors} from '../helpers/Errors.sol';

/**
 * @title WadRayMath library
 * @author Aave
 * @dev Provides mul and div function for wads (decimal numbers with 18 digits precision) and rays (decimals with 27 digits)
 **/

library WadRayMath {
    uint256 internal constant WAD = 1e18;
    uint256 internal constant halfWAD = WAD / 2;

    uint256 internal constant RAY = 1e27;
    uint256 internal constant halfRAY = RAY / 2;

    uint256 internal constant WAD_RAY_RATIO = 1e9;

    /**
     * @return One ray, 1e27
     **/
    function ray() internal pure returns (uint256) {
        return RAY;
    }

    /**
     * @return One wad, 1e18
     **/

    function wad() internal pure returns (uint256) {
        return WAD;
    }

    /**
     * @return Half ray, 1e27/2
     **/
    function halfRay() internal pure returns (uint256) {
        return halfRAY;
    }

    /**
     * @return Half ray, 1e18/2
     **/
    function halfWad() internal pure returns (uint256) {
        return halfWAD;
    }

    /**
     * @dev Multiplies two wad, rounding half up to the nearest wad
     * @param a Wad
     * @param b Wad
     * @return The result of a*b, in wad
     **/
    function wadMul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0 || b == 0) {
            return 0;
        }

        require(a <= (type(uint256).max - halfWAD) / b, Errors.MATH_MULTIPLICATION_OVERFLOW);

        return (a * b + halfWAD) / WAD;
    }

    /**
     * @dev Divides two wad, rounding half up to the nearest wad
     * @param a Wad
     * @param b Wad
     * @return The result of a/b, in wad
     **/
    function wadDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0, Errors.MATH_DIVISION_BY_ZERO);
        uint256 halfB = b / 2;

        require(a <= (type(uint256).max - halfB) / WAD, Errors.MATH_MULTIPLICATION_OVERFLOW);

        return (a * WAD + halfB) / b;
    }

    /**
     * @dev Multiplies two ray, rounding half up to the nearest ray
     * @param a Ray
     * @param b Ray
     * @return The result of a*b, in ray
     **/
    function rayMul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0 || b == 0) {
            return 0;
        }

        require(a <= (type(uint256).max - halfRAY) / b, Errors.MATH_MULTIPLICATION_OVERFLOW);

        return (a * b + halfRAY) / RAY;
    }

    /**
     * @dev Multiplies two ray, truncating the mantissa
     * @param a Ray
     * @param b Ray
     * @return The result of a*b, in ray
     **/
    function rayMulTruncate(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0 || b == 0) {
            return 0;
        }
        return (a * b) / RAY;
    }

    /**
     * @dev Divides two ray, rounding half up to the nearest ray
     * @param a Ray
     * @param b Ray
     * @return The result of a/b, in ray
     **/
    function rayDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0, Errors.MATH_DIVISION_BY_ZERO);
        uint256 halfB = b / 2;

        require(a <= (type(uint256).max - halfB) / RAY, Errors.MATH_MULTIPLICATION_OVERFLOW);

        return (a * RAY + halfB) / b;
    }

    /**
     * @dev Divides two ray, truncating the mantissa
     * @param a Ray
     * @param b Ray
     * @return The result of a/b, in ray
     **/
    function rayDivTruncate(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0, Errors.MATH_DIVISION_BY_ZERO);
        return (a * RAY) / b;
    }

    /**
     * @dev Casts ray down to wad
     * @param a Ray
     * @return a casted to wad, rounded half up to the nearest wad
     **/
    function rayToWad(uint256 a) internal pure returns (uint256) {
        uint256 halfRatio = WAD_RAY_RATIO / 2;
        uint256 result = halfRatio + a;
        require(result >= halfRatio, Errors.MATH_ADDITION_OVERFLOW);

        return result / WAD_RAY_RATIO;
    }

    /**
     * @dev Converts wad up to ray
     * @param a Wad
     * @return a converted in ray
     **/
    function wadToRay(uint256 a) internal pure returns (uint256) {
        uint256 result = a * WAD_RAY_RATIO;
        require(result / WAD_RAY_RATIO == a, Errors.MATH_MULTIPLICATION_OVERFLOW);
        return result;
    }
}

// File: contracts/libraries/math/MathUtils.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;

import {WadRayMath} from './WadRayMath.sol';

library MathUtils {
    using WadRayMath for uint256;

    /// @dev Ignoring leap years
    uint256 internal constant SECONDS_PER_YEAR = 365 days;

    /**
     * @dev Function to calculate the interest accumulated using a linear interest rate formula
     * @param rate The interest rate, in ray
     * @param lastUpdateTimestamp The timestamp of the last update of the interest
     * @return The interest rate linearly accumulated during the timeDelta, in ray
     **/

    function calculateLinearInterest(uint256 rate, uint40 lastUpdateTimestamp) external view returns (uint256) {
        //solium-disable-next-line
        uint256 timeDifference = block.timestamp - (uint256(lastUpdateTimestamp));

        return (rate * timeDifference) / SECONDS_PER_YEAR + WadRayMath.ray();
    }

    function calculateBorrowInterest(
        uint256 borrowRate,
        uint256 amount,
        uint256 duration
    ) external pure returns (uint256) {
        return amount.rayMul(borrowRate.rayMul(duration).rayDiv(SECONDS_PER_YEAR));
    }

    function calculateBorrowInterestPerSecond(uint256 borrowRate, uint256 amount) external pure returns (uint256) {
        return amount.rayMul(borrowRate).rayDiv(SECONDS_PER_YEAR);
    }

    function calculateLoanSupplyRate(
        uint256 availableLiquidity,
        uint256 totalBorrows,
        uint256 borrowRate
    ) external pure returns (uint256 loanSupplyRate, uint256 utilizationRate) {
        utilizationRate = (totalBorrows == 0 && availableLiquidity == 0)
            ? 0
            : totalBorrows.rayDiv(availableLiquidity + totalBorrows);
        loanSupplyRate = utilizationRate.rayMul(borrowRate);
    }
}

// File: contracts/libraries/math/PercentageMath.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;

import '../helpers/Errors.sol';

/**
 * @title PercentageMath library
 * @author Aave
 * @notice Provides functions to perform percentage calculations
 * @dev Percentages are defined by default with 2 decimals of precision (100.00). The precision is indicated by PERCENTAGE_FACTOR
 * @dev Operations are rounded half up
 **/

library PercentageMath {
  uint256 constant PERCENTAGE_FACTOR = 1e4; //percentage plus two decimals
  uint256 constant HALF_PERCENT = PERCENTAGE_FACTOR / 2;

  /**
   * @dev Executes a percentage multiplication
   * @param value The value of which the percentage needs to be calculated
   * @param percentage The percentage of the value to be calculated
   * @return The percentage of value
   **/
  function percentMul(uint256 value, uint256 percentage) internal pure returns (uint256) {
    if (value == 0 || percentage == 0) {
      return 0;
    }

    require(
      value <= (type(uint256).max - HALF_PERCENT) / percentage,
      Errors.MATH_MULTIPLICATION_OVERFLOW
    );

    return (value * percentage + HALF_PERCENT) / PERCENTAGE_FACTOR;
  }

  /**
   * @dev Executes a percentage division
   * @param value The value of which the percentage needs to be calculated
   * @param percentage The percentage of the value to be calculated
   * @return The value divided the percentage
   **/
  function percentDiv(uint256 value, uint256 percentage) internal pure returns (uint256) {
    require(percentage != 0, Errors.MATH_DIVISION_BY_ZERO);
    uint256 halfPercentage = percentage / 2;

    require(
      value <= (type(uint256).max - halfPercentage) / PERCENTAGE_FACTOR,
      Errors.MATH_MULTIPLICATION_OVERFLOW
    );

    return (value * PERCENTAGE_FACTOR + halfPercentage) / percentage;
  }
}

// File: contracts/libraries/helpers/Errors.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.10;

library Errors {
    // common
    string public constant MATH_MULTIPLICATION_OVERFLOW = '100';
    string public constant MATH_ADDITION_OVERFLOW = '101';
    string public constant MATH_DIVISION_BY_ZERO = '102';

    string public constant ETH_TRANSFER_FAILED = '110';
    string public constant RECEIVE_NOT_ALLOWED = '111';
    string public constant FALLBACK_NOT_ALLOWED = '112';
    string public constant APPROVAL_FAILED = '113';

    // setting/factor
    string public constant SETTING_ZERO_ADDRESS_NOT_ALLOWED = '115';
    string public constant SETTING_RESERVE_FACTOR_NOT_ALLOWED = '116';
    string public constant SETTING_WHITELIST_INVALID_RESERVE_ID = '117';
    string public constant SETTING_WHITELIST_NFT_ADDRESS_IS_ZERO = '118';
    string public constant SETTING_WHITELIST_NFT_DURATION_OUT_OF_ORDER = '119';
    string public constant SETTING_WHITELIST_NFT_NAME_EMPTY = '120';
    string public constant SETTING_WHITELIST_NFT_SYMBOL_EMPTY = '121';
    string public constant SETTING_WHITELIST_NFT_LTV_NOT_ALLOWED = '122';

    // settings/acl
    string public constant ACL_ONLY_GOVERNANCE_CAN_CALL = '200';
    string public constant ACL_ONLY_EMERGENCY_ADMIN_CAN_CALL = '201';
    string public constant ACL_ONLY_POOL_ADMIN_CAN_CALL = '202';
    string public constant ACL_ONLY_LIQUIDATOR_CAN_CALL = '203';
    string public constant ACL_ONLY_AIRDROP_OPERATOR_CAN_CALL = '204';
    string public constant ACL_ONLY_POOL_CAN_CALL = '205';

    // lending & borrowing
    // reserve
    string public constant RESERVE_DOES_NOT_EXIST = '300';
    string public constant RESERVE_LIQUIDITY_INSUFFICIENT = '301';
    string public constant RESERVE_INDEX_OVERFLOW = '302';
    string public constant RESERVE_SWITCH_MONEY_MARKET_STATE_ERROR = '303';
    string public constant RESERVE_TREASURY_FACTOR_NOT_ALLOWED = '304';
    string public constant RESERVE_TOKEN_CAN_NOT_BE_CLAIMED = '305';

    // token
    string public constant AMOUNT_SCALED_IS_ZERO = '310';
    string public constant AMOUNT_TRANSFER_OVERFLOW = '311';

    //deposit
    string public constant DEPOSIT_AMOUNT_SHOULD_BE_BIGGER_THAN_ZERO = '320';

    // withdraw
    string public constant WITHDRAW_AMOUNT_NOT_ALLOWED = '321';
    string public constant WITHDRAW_LIQUIDITY_NOT_SUFFICIENT = '322';

    // borrow
    string public constant BORROW_DURATION_NOT_ALLOWED = '330';
    string public constant BORROW_AMOUNT_EXCEED_BORROW_LIMIT = '331';
    string public constant NFT_ADDRESS_IS_NOT_IN_WHITELIST = '332';

    // repay
    string public constant REPAY_STATUS_ERROR = '333';
    string public constant REPAY_MSG_VALUE_ERROR = '334';

    // extend
    string public constant EXTEND_STATUS_ERROR = '335';
    string public constant EXTEND_MSG_VALUE_ERROR = '336';

    // liquidate
    string public constant START_LIQUIDATION_STATUS_ERROR = '360';
    string public constant END_LIQUIDATION_STATUS_ERROR = '361';
    string public constant END_LIQUIDATION_AMOUNT_ERROR = '362';

    // loan
    string public constant LOAN_DOES_NOT_EXIST = '400';
    string public constant LOAN_SET_STATUS_ERROR = '401';
    string public constant LOAN_REPAYER_IS_NOT_OWNER = '402';
    string public constant LOAN_LIQUIDATING_STATUS_CAN_NOT_BE_UPDATED = '403';
    string public constant LOAN_CALLER_IS_NOT_OWNER = '404';
    string public constant LOAN_COLLATERAL_NFT_CAN_NOT_BE_CLAIMED = '405';

    string public constant FLASHCLAIM_EXECUTOR_ERROR = '410';
    string public constant FLASHCLAIM_STATUS_ERROR = '411';

    // money market
    string public constant MONEY_MARKET_DEPOSIT_AMOUNT_NOT_ALLOWED = '500';
    string public constant MONEY_MARKET_WITHDRAW_AMOUNT_NOT_ALLOWED = '501';
    string public constant MONEY_MARKET_APPROVAL_FAILED = '502';
    string public constant MONEY_MARKET_DELEGATE_CALL_ERROR = '503';
    string public constant MONEY_MARKET_REQUIRE_DELEGATE_CALL = '504';
    string public constant MONEY_MARKET_WITHDRAW_AMOUNT_NOT_MATCH = '505';

    // price oracle
    string public constant PRICE_ORACLE_HAS_NO_PRICE_FEED = '600';
    string public constant PRICE_ORACLE_INCORRECT_TIMESTAMP = '601';
    string public constant PRICE_ORACLE_PARAMS_ERROR = '602';
}

// File: contracts/interfaces/IOpenSkyIncentivesController.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.10;

interface IOpenSkyIncentivesController {
    function handleAction(
        address account,
        uint256 userBalance,
        uint256 totalSupply
    ) external;

    function getRewardsBalance(address[] calldata assets, address user) external view returns (uint256);

    function claimRewards(
        address[] calldata assets,
        uint256 amount,
        address to,
        bool stake
    ) external returns (uint256);
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @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
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 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);
            }
        }
    }
}

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



// SPDX-License-Identifier: MIT

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/token/ERC721/ERC721.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC721.sol";
import "./IERC721Receiver.sol";
import "./extensions/IERC721Metadata.sol";
import "../../utils/Address.sol";
import "../../utils/Context.sol";
import "../../utils/Strings.sol";
import "../../utils/introspection/ERC165.sol";

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension, but not including the Enumerable extension, which is available separately as
 * {ERC721Enumerable}.
 */
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Mapping from token ID to owner address
    mapping(uint256 => address) private _owners;

    // Mapping owner address to token count
    mapping(address => uint256) private _balances;

    // Mapping from token ID to approved address
    mapping(uint256 => address) private _tokenApprovals;

    // Mapping from owner to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: balance query for the zero address");
        return _balances[owner];
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    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;
    }

    /**
     * @dev See {IERC721Metadata-name}.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev See {IERC721Metadata-symbol}.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    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())) : "";
    }

    /**
     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
     * by default, can be overriden in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return "";
    }

    /**
     * @dev See {IERC721-approve}.
     */
    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);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), "ERC721: approved query for nonexistent token");

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    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);
    }

    /**
     * @dev See {IERC721-isApprovedForAll}.
     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");

        _transfer(from, to, tokenId);
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    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);
    }

    /**
     * @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.
     *
     * `_data` is additional data, it has no specified format and it is sent in call to `to`.
     *
     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
     * implement alternative mechanisms to perform token transfer, such as signature-based.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    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");
    }

    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted (`_mint`),
     * and stop existing when they are burned (`_burn`).
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _owners[tokenId] != address(0);
    }

    /**
     * @dev Returns whether `spender` is allowed to manage `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    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));
    }

    /**
     * @dev Safely mints `tokenId` and transfers it to `to`.
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(address to, uint256 tokenId) internal virtual {
        _safeMint(to, tokenId, "");
    }

    /**
     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
     */
    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"
        );
    }

    /**
     * @dev Mints `tokenId` and transfers it to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - `to` cannot be the zero address.
     *
     * Emits a {Transfer} event.
     */
    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);
    }

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721.ownerOf(tokenId);

        _beforeTokenTransfer(owner, address(0), tokenId);

        // Clear approvals
        _approve(address(0), tokenId);

        _balances[owner] -= 1;
        delete _owners[tokenId];

        emit Transfer(owner, address(0), tokenId);
    }

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    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);

        // Clear approvals from the previous owner
        _approve(address(0), tokenId);

        _balances[from] -= 1;
        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(from, to, tokenId);
    }

    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits a {Approval} event.
     */
    function _approve(address to, uint256 tokenId) internal virtual {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
    }

    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
     * The call is not executed if the target address is not a contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param _data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    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;
        }
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {
    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}

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



// SPDX-License-Identifier: MIT

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

    /**
     * @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 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);

    /**
     * @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;
}

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



// SPDX-License-Identifier: MIT

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 `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {
    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}

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



// SPDX-License-Identifier: MIT

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/ERC165.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC165.sol";

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

// File: @openzeppelin/contracts/token/ERC1155/utils/ERC1155Receiver.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC1155Receiver.sol";
import "../../../utils/introspection/ERC165.sol";

/**
 * @dev _Available since v3.1._
 */
abstract contract ERC1155Receiver is ERC165, IERC1155Receiver {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return interfaceId == type(IERC1155Receiver).interfaceId || super.supportsInterface(interfaceId);
    }
}

// File: @openzeppelin/contracts/token/ERC1155/IERC1155Receiver.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

/**
 * @dev _Available since v3.1._
 */
interface IERC1155Receiver is IERC165 {
    /**
        @dev Handles the receipt of a single ERC1155 token type. This function is
        called at the end of a `safeTransferFrom` after the balance has been updated.
        To accept the transfer, this must return
        `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))`
        (i.e. 0xf23a6e61, or its own function selector).
        @param operator The address which initiated the transfer (i.e. msg.sender)
        @param from The address which previously owned the token
        @param id The ID of the token being transferred
        @param value The amount of tokens being transferred
        @param data Additional data with no specified format
        @return `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))` if transfer is allowed
    */
    function onERC1155Received(
        address operator,
        address from,
        uint256 id,
        uint256 value,
        bytes calldata data
    ) external returns (bytes4);

    /**
        @dev Handles the receipt of a multiple ERC1155 token types. This function
        is called at the end of a `safeBatchTransferFrom` after the balances have
        been updated. To accept the transfer(s), this must return
        `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))`
        (i.e. 0xbc197c81, or its own function selector).
        @param operator The address which initiated the batch transfer (i.e. msg.sender)
        @param from The address which previously owned the token
        @param ids An array containing ids of each token being transferred (order and length must match values array)
        @param values An array containing amounts of each token being transferred (order and length must match ids array)
        @param data Additional data with no specified format
        @return `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))` if transfer is allowed
    */
    function onERC1155BatchReceived(
        address operator,
        address from,
        uint256[] calldata ids,
        uint256[] calldata values,
        bytes calldata data
    ) external returns (bytes4);
}