// File: SwapDebtForCollZap.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.19;

import "Address.sol";
import "IERC20.sol";
import "IDebtToken.sol";

interface IFeeConverter {
    function swapDebtForColl(address collateral, uint256 debtAmount) external returns (uint256);
}

/**
    @title Swap Debt for Collateral Zap
 */
contract SwapDebtForCollZap {
    using Address for address;
    bytes32 private constant _RETURN_VALUE = keccak256("ERC3156FlashBorrower.onFlashLoan");

    IDebtToken public immutable debtToken;
    IFeeConverter public immutable feeConverter;

    constructor(IDebtToken _debtToken, IFeeConverter _feeConverter) {
        debtToken = _debtToken;
        feeConverter = _feeConverter;

        _debtToken.approve(address(_feeConverter), type(uint256).max);
        _debtToken.approve(address(_debtToken), type(uint256).max);
    }

    /**
        @notice Use a flashloan to purchase available collateral with mkUSD and
                sell the collateral in the same transaction
        @dev Remaining mkUSD and `collateral` balances are transferred to the caller.
             The transaction will revert if it is not profitable.
        @param collateral Collateral to purchase
        @param debtAmount Amount of mkUSD to flashloan and use to purchase `collateral`
        @param minCollReceived Minimum amount of `collateral` received
        @param swapRouter Router contract used to swap `collateral` back to `debt`
        @param swapData Calldata used when calling `swapRouter`. Must be generated
                        off-chain.
     */
    function swapDebtForColl(
        IERC20 collateral,
        uint256 debtAmount,
        uint256 minCollReceived,
        address swapRouter,
        bytes calldata swapData
    ) external {
        bytes memory data = abi.encode(collateral, minCollReceived, swapRouter, swapData);

        debtToken.flashLoan(address(this), address(debtToken), debtAmount, data);

        uint256 amount = collateral.balanceOf(address(this));
        if (amount != 0) collateral.transfer(msg.sender, amount);

        amount = debtToken.balanceOf(address(this));
        if (amount != 0) debtToken.transfer(msg.sender, amount);
    }

    function onFlashLoan(
        address caller,
        address token,
        uint amount,
        uint fee,
        bytes calldata data
    ) external returns (bytes32) {
        require(caller == address(this));

        (address collateral, uint256 minCollReceived, address swapRouter, bytes memory swapData) = abi.decode(
            data,
            (address, uint256, address, bytes)
        );

        uint256 collAmount = feeConverter.swapDebtForColl(collateral, amount);

        require(collAmount >= minCollReceived);

        IERC20(collateral).approve(swapRouter, collAmount);
        swapRouter.functionCall(swapData);

        return _RETURN_VALUE;
    }
}

// File: Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [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://consensys.net/diligence/blog/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/v0.8.0/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 functionCallWithValue(target, data, 0, "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");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or 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 {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // 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
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// File: IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

// File: IDebtToken.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

interface IDebtToken {
    event Approval(address indexed owner, address indexed spender, uint256 value);
    event MessageFailed(uint16 _srcChainId, bytes _srcAddress, uint64 _nonce, bytes _payload, bytes _reason);
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    event ReceiveFromChain(uint16 indexed _srcChainId, address indexed _to, uint256 _amount);
    event RetryMessageSuccess(uint16 _srcChainId, bytes _srcAddress, uint64 _nonce, bytes32 _payloadHash);
    event SendToChain(uint16 indexed _dstChainId, address indexed _from, bytes _toAddress, uint256 _amount);
    event SetMinDstGas(uint16 _dstChainId, uint16 _type, uint256 _minDstGas);
    event SetPrecrime(address precrime);
    event SetTrustedRemote(uint16 _remoteChainId, bytes _path);
    event SetTrustedRemoteAddress(uint16 _remoteChainId, bytes _remoteAddress);
    event SetUseCustomAdapterParams(bool _useCustomAdapterParams);
    event Transfer(address indexed from, address indexed to, uint256 value);

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

    function burn(address _account, uint256 _amount) external;

    function burnWithGasCompensation(address _account, uint256 _amount) external returns (bool);

    function decreaseAllowance(address spender, uint256 subtractedValue) external returns (bool);

    function enableTroveManager(address _troveManager) external;

    function flashLoan(address receiver, address token, uint256 amount, bytes calldata data) external returns (bool);

    function forceResumeReceive(uint16 _srcChainId, bytes calldata _srcAddress) external;

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

    function lzReceive(uint16 _srcChainId, bytes calldata _srcAddress, uint64 _nonce, bytes calldata _payload) external;

    function mint(address _account, uint256 _amount) external;

    function mintWithGasCompensation(address _account, uint256 _amount) external returns (bool);

    function nonblockingLzReceive(
        uint16 _srcChainId,
        bytes calldata _srcAddress,
        uint64 _nonce,
        bytes calldata _payload
    ) external;

    function permit(
        address owner,
        address spender,
        uint256 amount,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    function renounceOwnership() external;

    function returnFromPool(address _poolAddress, address _receiver, uint256 _amount) external;

    function sendToSP(address _sender, uint256 _amount) external;

    function setConfig(uint16 _version, uint16 _chainId, uint256 _configType, bytes calldata _config) external;

    function setMinDstGas(uint16 _dstChainId, uint16 _packetType, uint256 _minGas) external;

    function setPayloadSizeLimit(uint16 _dstChainId, uint256 _size) external;

    function setPrecrime(address _precrime) external;

    function setReceiveVersion(uint16 _version) external;

    function setSendVersion(uint16 _version) external;

    function setTrustedRemote(uint16 _srcChainId, bytes calldata _path) external;

    function setTrustedRemoteAddress(uint16 _remoteChainId, bytes calldata _remoteAddress) external;

    function setUseCustomAdapterParams(bool _useCustomAdapterParams) external;

    function transfer(address recipient, uint256 amount) external returns (bool);

    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    function transferOwnership(address newOwner) external;

    function retryMessage(
        uint16 _srcChainId,
        bytes calldata _srcAddress,
        uint64 _nonce,
        bytes calldata _payload
    ) external payable;

    function sendFrom(
        address _from,
        uint16 _dstChainId,
        bytes calldata _toAddress,
        uint256 _amount,
        address _refundAddress,
        address _zroPaymentAddress,
        bytes calldata _adapterParams
    ) external payable;

    function DEBT_GAS_COMPENSATION() external view returns (uint256);

    function DEFAULT_PAYLOAD_SIZE_LIMIT() external view returns (uint256);

    function FLASH_LOAN_FEE() external view returns (uint256);

    function NO_EXTRA_GAS() external view returns (uint256);

    function PT_SEND() external view returns (uint16);

    function allowance(address owner, address spender) external view returns (uint256);

    function balanceOf(address account) external view returns (uint256);

    function borrowerOperationsAddress() external view returns (address);

    function circulatingSupply() external view returns (uint256);

    function decimals() external view returns (uint8);

    function domainSeparator() external view returns (bytes32);

    function estimateSendFee(
        uint16 _dstChainId,
        bytes calldata _toAddress,
        uint256 _amount,
        bool _useZro,
        bytes calldata _adapterParams
    ) external view returns (uint256 nativeFee, uint256 zroFee);

    function factory() external view returns (address);

    function failedMessages(uint16, bytes calldata, uint64) external view returns (bytes32);

    function flashFee(address token, uint256 amount) external view returns (uint256);

    function gasPool() external view returns (address);

    function getConfig(
        uint16 _version,
        uint16 _chainId,
        address,
        uint256 _configType
    ) external view returns (bytes memory);

    function getTrustedRemoteAddress(uint16 _remoteChainId) external view returns (bytes memory);

    function isTrustedRemote(uint16 _srcChainId, bytes calldata _srcAddress) external view returns (bool);

    function lzEndpoint() external view returns (address);

    function maxFlashLoan(address token) external view returns (uint256);

    function minDstGasLookup(uint16, uint16) external view returns (uint256);

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

    function nonces(address owner) external view returns (uint256);

    function owner() external view returns (address);

    function payloadSizeLimitLookup(uint16) external view returns (uint256);

    function permitTypeHash() external view returns (bytes32);

    function precrime() external view returns (address);

    function stabilityPoolAddress() external view returns (address);

    function supportsInterface(bytes4 interfaceId) external view returns (bool);

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

    function token() external view returns (address);

    function totalSupply() external view returns (uint256);

    function troveManager(address) external view returns (bool);

    function trustedRemoteLookup(uint16) external view returns (bytes memory);

    function useCustomAdapterParams() external view returns (bool);

    function version() external view returns (string memory);
}