// SPDX-License-Identifier: BUSL-1.1

pragma solidity 0.8.4;

import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "../utils/ContractKeys.sol";
import "../interfaces/IPermittedERC20s.sol";
import "../interfaces/INftfiHub.sol";
import "../interfaces/IDirectLoanCoordinator.sol";
import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";

contract TokenTrade {
    using SafeERC20 for IERC20;
    using ECDSA for bytes32;

    INftfiHub public hub;

    bytes32 public immutable LOAN_COORDINATOR;

    constructor(address _nftfiHub, bytes32 _loanCoordinatorKey) {
        hub = INftfiHub(_nftfiHub);
        LOAN_COORDINATOR = _loanCoordinatorKey;
    }

    /**
     * @notice A mapping that takes both a user's address and a trade nonce that was first used when signing an
     * off-chain order and checks whether that nonce has previously either been used for a trade, or has been
     * pre-emptively cancelled. The nonce referred to here is not the same as an Ethereum account's nonce.
     * We are referring instead to nonces that are used by both the lender and the borrower when they are first
     * signing off-chain NFTfi orders.
     *
     * These nonces can be any uint256 value that the user has not previously used to sign an off-chain order. Each
     * nonce can be used at most once per user within NFTfi, regardless of whether they are the lender or the borrower
     * in that situation. This serves two purposes. First, it prevents replay attacks where an attacker would submit a
     * user's off-chain order more than once. Second, it allows a user to cancel an off-chain order by calling
     * NFTfi.cancelTradeCommitment(), which marks the nonce as used and prevents any future trade from
     * using the user's off-chain order that contains that nonce.
     */
    mapping(address => mapping(uint256 => bool)) private _nonceHasBeenUsedForUser;

    /**
     * @notice This function can be called by the initiator to cancel all off-chain orders that they
     * have signed that contain this nonce. If the off-chain orders were created correctly, there should only be one
     * off-chain order that contains this nonce at all.
     *
     * The nonce referred to here is not the same as an Ethereum account's nonce. We are referring
     * instead to nonces that are used by both the lender and the borrower when they are first signing off-chain NFTfi
     * orders. These nonces can be any uint256 value that the user has not previously used to sign an off-chain order.
     * Each nonce can be used at most once per user within NFTfi, regardless of whether they are the lender or the
     * borrower in that situation. This serves two purposes. First, it prevents replay attacks where an attacker would
     * submit a user's off-chain order more than once. Second, it allows a user to cancel an off-chain order by calling
     * NFTfi.cancelTradeCommitment(), which marks the nonce as used and prevents any future trade from
     * using the user's off-chain order that contains that nonce.
     *
     * @param  _nonce - User nonce
     */
    function cancelTradeCommitment(uint256 _nonce) external {
        require(!_nonceHasBeenUsedForUser[msg.sender][_nonce], "Invalid nonce");
        _nonceHasBeenUsedForUser[msg.sender][_nonce] = true;
    }

    /**
     * @notice This function can be used to view whether a particular nonce for a particular user has already been used,
     * either from a successful trade or a cancelled off-chain order.
     *
     * @param _user - The address of the user. This function works for both lenders and borrowers alike.
     * @param  _nonce - The nonce referred to here is not the same as an Ethereum account's nonce. We are referring
     * instead to nonces that are used by both the lender and the borrower when they are first signing off-chain
     * NFTfi orders. These nonces can be any uint256 value that the user has not previously used to sign an off-chain
     * order. Each nonce can be used at most once per user within NFTfi, regardless of whether they are the lender or
     * the borrower in that situation. This serves two purposes:
     * - First, it prevents replay attacks where an attacker would submit a user's off-chain order more than once.
     * - Second, it allows a user to cancel an off-chain order by calling NFTfi.cancelTradeCommitment()
     * , which marks the nonce as used and prevents any future trade from using the user's off-chain order that contains
     * that nonce.
     *
     * @return A bool representing whether or not this nonce has been used for this user.
     */
    function getNonceUsage(address _user, uint256 _nonce) external view returns (bool) {
        return _nonceHasBeenUsedForUser[_user][_nonce];
    }

    /**
     * @notice trade initiator sells their obligation receipt to the accepter
     * Activates an off chain proposed ERC20-loanNFT token trade, works very much like the loan offer acceptal
     * both parties have to approve the token allowances for the trade contract before calling this function
     *
     * parameters: see trade()
     */
    function sellObligationReceipt(
        address _tradeERC20,
        uint256 _nftId,
        uint256 _erc20Amount,
        address _buyer,
        uint256 _buyerNonce,
        uint256 _expiry,
        bytes memory _buyerSignature
    ) external {
        require(!_nonceHasBeenUsedForUser[_buyer][_buyerNonce], "Buyer nonce invalid");
        _nonceHasBeenUsedForUser[_buyer][_buyerNonce] = true;
        IDirectLoanCoordinator loanCoordinator = IDirectLoanCoordinator(hub.getContract(LOAN_COORDINATOR));
        address obligationReceipt = loanCoordinator.obligationReceiptToken();
        require(
            isValidTradeSignature(
                _tradeERC20,
                obligationReceipt,
                _nftId,
                _erc20Amount,
                _buyer,
                _buyerNonce,
                _expiry,
                _buyerSignature
            ),
            "Trade signature is invalid"
        );
        trade(_tradeERC20, obligationReceipt, _nftId, _erc20Amount, msg.sender, _buyer);
    }

    /**
     * @notice trade initiator buys obligation receipt of the accepter
     * Activates an off chain proposed ERC20-loanNFT token trade, works very much like the loan offer acceptal
     * both parties have to approve the token allowances for the trade contract before calling this function
     *
     * parameters: see trade()
     */
    function buyObligationReceipt(
        address _tradeERC20,
        uint256 _nftId,
        uint256 _erc20Amount,
        address _seller,
        uint256 _sellerNonce,
        uint256 _expiry,
        bytes memory _sellerSignature
    ) external {
        require(!_nonceHasBeenUsedForUser[_seller][_sellerNonce], "Seller nonce invalid");
        _nonceHasBeenUsedForUser[_seller][_sellerNonce] = true;
        IDirectLoanCoordinator loanCoordinator = IDirectLoanCoordinator(hub.getContract(LOAN_COORDINATOR));
        address obligationReceipt = loanCoordinator.obligationReceiptToken();
        require(
            isValidTradeSignature(
                _tradeERC20,
                obligationReceipt,
                _nftId,
                _erc20Amount,
                _seller,
                _sellerNonce,
                _expiry,
                _sellerSignature
            ),
            "Trade signature is invalid"
        );
        trade(_tradeERC20, obligationReceipt, _nftId, _erc20Amount, _seller, msg.sender);
    }

    /**
     * @notice trade initiator sells their promissory note to the accepter
     * Activates an off chain proposed ERC20-loanNFT token trade, works very much like the loan offer acceptal
     * both parties have to approve the token allowances for the trade contract before calling this function
     *
     * parameters: see trade()
     */
    function sellPromissoryNote(
        address _tradeERC20,
        uint256 _nftId,
        uint256 _erc20Amount,
        address _buyer,
        uint256 _buyerNonce,
        uint256 _expiry,
        bytes memory _buyerSignature
    ) external {
        require(!_nonceHasBeenUsedForUser[_buyer][_buyerNonce], "Buyer nonce invalid");
        _nonceHasBeenUsedForUser[_buyer][_buyerNonce] = true;
        IDirectLoanCoordinator loanCoordinator = IDirectLoanCoordinator(hub.getContract(LOAN_COORDINATOR));
        address promissoryNote = loanCoordinator.promissoryNoteToken();
        require(
            isValidTradeSignature(
                _tradeERC20,
                promissoryNote,
                _nftId,
                _erc20Amount,
                _buyer,
                _buyerNonce,
                _expiry,
                _buyerSignature
            ),
            "Trade signature is invalid"
        );
        trade(_tradeERC20, promissoryNote, _nftId, _erc20Amount, msg.sender, _buyer);
    }

    /**
     * @notice trade initiator buys promissory note of the accepter
     * Activates an off chain proposed ERC20-loanNFT token trade, works very much like the loan offer acceptal
     * both parties have to approve the token allowances for the trade contract before calling this function
     *
     * parameters: see trade()
     */
    function buyPromissoryNote(
        address _tradeERC20,
        uint256 _nftId,
        uint256 _erc20Amount,
        address _seller,
        uint256 _sellerNonce,
        uint256 _expiry,
        bytes memory _sellerSignature
    ) external {
        require(!_nonceHasBeenUsedForUser[_seller][_sellerNonce], "Seller nonce invalid");
        _nonceHasBeenUsedForUser[_seller][_sellerNonce] = true;
        IDirectLoanCoordinator loanCoordinator = IDirectLoanCoordinator(hub.getContract(LOAN_COORDINATOR));
        address promissoryNote = loanCoordinator.promissoryNoteToken();
        require(
            isValidTradeSignature(
                _tradeERC20,
                promissoryNote,
                _nftId,
                _erc20Amount,
                _seller,
                _sellerNonce,
                _expiry,
                _sellerSignature
            ),
            "Trade signature is invalid"
        );
        trade(_tradeERC20, promissoryNote, _nftId, _erc20Amount, _seller, msg.sender);
    }

    /**
     * @notice Activates an off chain proposed ERC20-loanNFT token trade, works very much like the loan offer acceptal
     * both parties have to approve the token allowances for the trade contract before calling this function
     *
     * @param _tradeERC20 - Contract address for the token denomination of the erc20 side of the trade,
     * can only be a premitted erc20 token
     * @param _tradeNft - Contract address for the loanNFT side of the trade,
     * can only be the 'promissory note' or the 'obligation receipt' of the used loan coordinator
     * @param _nftId - ID of the loanNFT to be tradeped
     * true:
     *      initiator sells loanNFT for erc20, accepter buys loanNFT for erc20
     * false:
     *      initiator buys loanNFT for erc20, accepter sells loanNFT for erc20
     * @param _erc20Amount - amount of payment price in erc20 for the loanNFT
     * @param _seller - address of the user selling the loanNFT for ERC20 tokens
     * @param _buyer - address of the user buying the loanNFT for ERC20 tokens
     */
    function trade(
        address _tradeERC20,
        address _tradeNft,
        uint256 _nftId,
        uint256 _erc20Amount,
        address _seller,
        address _buyer
    ) internal {
        require(
            IPermittedERC20s(hub.getContract(ContractKeys.PERMITTED_ERC20S)).getERC20Permit(_tradeERC20),
            "Currency denomination is not permitted"
        );
        IERC20(_tradeERC20).safeTransferFrom(_buyer, _seller, _erc20Amount);
        IERC721(_tradeNft).safeTransferFrom(_seller, _buyer, _nftId);
    }

    /**
     * @notice This function is called in trade()to validate the trade initiator's signature that the lender
     * has provided off-chain to verify that they did indeed want to
     * agree to this loan renegotiation according to these terms.
     *
     * @param _tradeERC20 - Contract address for the token denomination of the erc20 side of the trade,
     * can only be a premitted erc20 token
     * @param _tradeNft - Contract address for the loanNFT side of the trade,
     * can only be the 'promissory note' or the 'obligation receipt' of the used loan coordinator
     * @param _nftId - ID of the loanNFT to be tradeped
     * @param _erc20Amount - amount of payment price in erc20 for the loanNFT
     * @param _accepter - address of the user accepting the proposed trade, they have created the off-chain signature
     * @param _accepterNonce - The nonce referred to here is not the same as an Ethereum account's nonce. We are
     * referring instead to nonces that are used by both the lender and the borrower when they are first signing
     * off-chain NFTfi orders. These nonces can be any uint256 value that the user has not previously used to sign an
     * off-chain order. Each nonce can be used at most once per user within NFTfi, regardless of whether they are the
     * lender or the borrower in that situation. This serves two purposes:
     * - First, it prevents replay attacks where an attacker would submit a user's off-chain order more than once.
     * - Second, it allows a user to cancel an off-chain order by calling NFTfi.cancelTradeCommitment()
     * , which marks the nonce as used and prevents any future trade from using the user's off-chain order that contains
     * that nonce.
     * @param _expiry - The date when the trade offer expires
     * @param _accepterSignature - The ECDSA signature of the trade initiator,
     * obtained off-chain ahead of time, signing the
     * following combination of parameters:
     * - tradeERC20,
     * - tradeLoanNft,
     * - loanNftId,
     * - erc20Amount,
     * - initiator,
     * - accepter,
     * - initiatorNonce,
     * - expiry,
     * - chainId
     */
    function isValidTradeSignature(
        address _tradeERC20,
        address _tradeNft,
        uint256 _nftId,
        uint256 _erc20Amount,
        address _accepter,
        uint256 _accepterNonce,
        uint256 _expiry,
        bytes memory _accepterSignature
    ) public view returns (bool) {
        require(block.timestamp <= _expiry, "Trade Signature has expired");
        if (_accepter == address(0)) {
            return false;
        } else {
            bytes32 message = keccak256(
                abi.encodePacked(
                    _tradeERC20,
                    _tradeNft,
                    _nftId,
                    _erc20Amount,
                    _accepter,
                    _accepterNonce,
                    _expiry,
                    getChainID()
                )
            );

            bytes32 messageWithEthSignPrefix = message.toEthSignedMessageHash();

            return (messageWithEthSignPrefix.recover(_accepterSignature) == _accepter);
        }
    }

    /**
     * @dev This function gets the current chain ID.
     */
    function getChainID() internal view returns (uint256) {
        uint256 id;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            id := chainid()
        }
        return id;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

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

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, 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;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/IERC20.sol)

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 `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

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

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

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

    /**
     * @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);
}

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

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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

// SPDX-License-Identifier: BUSL-1.1

pragma solidity 0.8.4;

/**
 * @title ContractKeys
 * @author NFTfi
 * @dev Common library for contract keys
 */
library ContractKeys {
    bytes32 public constant PERMITTED_ERC20S = bytes32("PERMITTED_ERC20S");
    bytes32 public constant PERMITTED_NFTS = bytes32("PERMITTED_NFTS");
    bytes32 public constant PERMITTED_PARTNERS = bytes32("PERMITTED_PARTNERS");
    bytes32 public constant NFT_TYPE_REGISTRY = bytes32("NFT_TYPE_REGISTRY");
    bytes32 public constant LOAN_REGISTRY = bytes32("LOAN_REGISTRY");
    bytes32 public constant PERMITTED_SNFT_RECEIVER = bytes32("PERMITTED_SNFT_RECEIVER");
    bytes32 public constant PERMITTED_BUNDLE_ERC20S = bytes32("PERMITTED_BUNDLE_ERC20S");
    bytes32 public constant PERMITTED_AIRDROPS = bytes32("PERMITTED_AIRDROPS");
    bytes32 public constant AIRDROP_RECEIVER = bytes32("AIRDROP_RECEIVER");
    bytes32 public constant AIRDROP_FACTORY = bytes32("AIRDROP_FACTORY");
    bytes32 public constant AIRDROP_FLASH_LOAN = bytes32("AIRDROP_FLASH_LOAN");
    bytes32 public constant NFTFI_BUNDLER = bytes32("NFTFI_BUNDLER");

    string public constant AIRDROP_WRAPPER_STRING = "AirdropWrapper";

    /**
     * @notice Returns the bytes32 representation of a string
     * @param _key the string key
     * @return id bytes32 representation
     */
    function getIdFromStringKey(string memory _key) external pure returns (bytes32 id) {
        require(bytes(_key).length <= 32, "invalid key");

        // solhint-disable-next-line no-inline-assembly
        assembly {
            id := mload(add(_key, 32))
        }
    }
}

// SPDX-License-Identifier: BUSL-1.1

pragma solidity 0.8.4;

interface IPermittedERC20s {
    function getERC20Permit(address _erc20) external view returns (bool);
}

// SPDX-License-Identifier: BUSL-1.1

pragma solidity 0.8.4;

/**
 * @title INftfiHub
 * @author NFTfi
 * @dev NftfiHub interface
 */
interface INftfiHub {
    function setContract(string calldata _contractKey, address _contractAddress) external;

    function getContract(bytes32 _contractKey) external view returns (address);
}

// SPDX-License-Identifier: BUSL-1.1

pragma solidity 0.8.4;

/**
 * @title IDirectLoanCoordinator
 * @author NFTfi
 * @dev DirectLoanCoordinator interface.
 */
interface IDirectLoanCoordinator {
    enum StatusType {
        NOT_EXISTS,
        NEW,
        RESOLVED
    }

    /**
     * @notice This struct contains data related to a loan
     *
     * @param smartNftId - The id of both the promissory note and obligation receipt.
     * @param status - The status in which the loan currently is.
     * @param loanContract - Address of the LoanType contract that created the loan.
     */
    struct Loan {
        address loanContract;
        uint64 smartNftId;
        StatusType status;
    }

    function registerLoan(address _lender, bytes32 _loanType) external returns (uint32);

    function mintObligationReceipt(uint32 _loanId, address _borrower) external;

    function resolveLoan(uint32 _loanId) external;

    function promissoryNoteToken() external view returns (address);

    function obligationReceiptToken() external view returns (address);

    function getLoanData(uint32 _loanId) external view returns (Loan memory);

    function isValidLoanId(uint32 _loanId, address _loanContract) external view returns (bool);
}

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

pragma solidity ^0.8.0;

import "../Strings.sol";

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

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

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

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

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

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

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

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

        return (signer, RecoverError.NoError);
    }

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

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

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

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

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

pragma solidity ^0.8.0;

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

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

pragma solidity ^0.8.1;

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

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

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

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

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

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

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

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

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

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

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

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

pragma solidity ^0.8.0;

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

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

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}
{"success": true, "error": null, "results": {}}