// File: lib/Cooler/src/CoolerFactory.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.15;

import {ERC20} from "solmate/tokens/ERC20.sol";
import {ClonesWithImmutableArgs} from "clones/ClonesWithImmutableArgs.sol";

import {Cooler} from "./Cooler.sol";

/// @title  Cooler Loans Factory.
/// @notice The Cooler Factory creates new Cooler escrow contracts.
/// @dev    This contract uses Clones (https://github.com/wighawag/clones-with-immutable-args)
///         to save gas on deployment.
contract CoolerFactory {
    using ClonesWithImmutableArgs for address;

    // --- ERRORS ----------------------------------------------------

    error NotFromFactory();
    error DecimalsNot18();

    // --- EVENTS ----------------------------------------------------

    /// @notice A global event when a new loan request is created.
    event RequestLoan(address indexed cooler, address collateral, address debt, uint256 reqID);
    /// @notice A global event when a loan request is rescinded.
    event RescindRequest(address indexed cooler, uint256 reqID);
    /// @notice A global event when a loan request is fulfilled.
    event ClearRequest(address indexed cooler, uint256 reqID, uint256 loanID);
    /// @notice A global event when a loan is repaid.
    event RepayLoan(address indexed cooler, uint256 loanID, uint256 amount);
    /// @notice A global event when a loan is extended.
    event ExtendLoan(address indexed cooler, uint256 loanID, uint8 times);
    /// @notice A global event when the collateral of defaulted loan is claimed.
    event DefaultLoan(address indexed cooler, uint256 loanID, uint256 amount);

    // -- STATE VARIABLES --------------------------------------------

    /// @notice Cooler reference implementation (deployed on creation to clone from).
    Cooler public immutable coolerImplementation;

    /// @notice Mapping to validate deployed coolers.
    mapping(address => bool) public created;

    /// @notice Mapping to prevent duplicate coolers.
    mapping(address => mapping(ERC20 => mapping(ERC20 => address)))
        private coolerFor;

    /// @notice Mapping to query Coolers for Collateral-Debt pair.
    mapping(ERC20 => mapping(ERC20 => address[])) public coolersFor;

    // --- INITIALIZATION --------------------------------------------

    constructor() {
        coolerImplementation = new Cooler();
    }

    // --- DEPLOY NEW COOLERS ----------------------------------------

    /// @notice creates a new Escrow contract for collateral and debt tokens.
    /// @param  collateral_ the token given as collateral.
    /// @param  debt_ the token to be lent. Interest is denominated in debt tokens.
    /// @return cooler address of the contract.
function generateCooler(ERC20 collateral_, ERC20 debt_) external returns (address cooler) {
    // Return address if cooler exists.
    cooler = coolerFor[msg.sender][collateral_][debt_];

    // Otherwise generate new cooler.
    if (cooler == address(0)) {
        if (collateral_.decimals() != 18 || debt_.decimals() != 18) revert DecimalsNot18();
        // Clone the cooler implementation.
        bytes memory coolerData = abi.encodePacked(
            msg.sender,              // owner
            address(collateral_),    // collateral
            address(debt_),          // debt
            address(this)            // factory
        );
        cooler = address(coolerImplementation).clone(coolerData);

        // Update storage accordingly.
        coolerFor[msg.sender][collateral_][debt_] = cooler;
        coolersFor[collateral_][debt_].push(cooler);
        created[cooler] = true;
    }
}

    // --- EMIT EVENTS -----------------------------------------------

    /// @notice Ensure that the called is a Cooler.
    modifier onlyFromFactory {        
        if (!created[msg.sender]) revert NotFromFactory();
        _;
    }

    /// @notice Emit a global event when a new loan request is created.
    function logRequestLoan(uint256 reqID_) external onlyFromFactory {
        emit RequestLoan(msg.sender, address(Cooler(msg.sender).collateral()), address(Cooler(msg.sender).debt()), reqID_);
    }

    /// @notice Emit a global event when a loan request is rescinded.
    function logRescindRequest(uint256 reqID_) external onlyFromFactory {
        emit RescindRequest(msg.sender, reqID_);
    }

    /// @notice Emit a global event when a loan request is fulfilled.
    function logClearRequest(uint256 reqID_, uint256 loanID_) external onlyFromFactory {
        emit ClearRequest(msg.sender, reqID_, loanID_);
    }

    /// @notice Emit a global event when a loan is repaid.
    function logRepayLoan(uint256 loanID_, uint256 repayment_) external onlyFromFactory {
        emit RepayLoan(msg.sender, loanID_, repayment_);
    }

    /// @notice Emit a global event when a loan is extended.
    function logExtendLoan(uint256 loanID_, uint8 times_) external onlyFromFactory {
        emit ExtendLoan(msg.sender, loanID_, times_);
    }

    /// @notice Emit a global event when the collateral of defaulted loan is claimed.
    function logDefaultLoan(uint256 loanID_, uint256 collateral_) external onlyFromFactory {
        emit DefaultLoan(msg.sender, loanID_, collateral_);
    }
}
// File: lib/solmate/src/tokens/ERC20.sol



// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity >=0.8.0;

/// @notice Modern and gas efficient ERC20 + EIP-2612 implementation.
/// @author Solmate (https://github.com/transmissions11/solmate/blob/main/src/tokens/ERC20.sol)
/// @author Modified from Uniswap (https://github.com/Uniswap/uniswap-v2-core/blob/master/contracts/UniswapV2ERC20.sol)
/// @dev Do not manually set balances without updating totalSupply, as the sum of all user balances must not exceed it.
abstract contract ERC20 {
    /*//////////////////////////////////////////////////////////////
                                 EVENTS
    //////////////////////////////////////////////////////////////*/

    event Transfer(address indexed from, address indexed to, uint256 amount);

    event Approval(address indexed owner, address indexed spender, uint256 amount);

    /*//////////////////////////////////////////////////////////////
                            METADATA STORAGE
    //////////////////////////////////////////////////////////////*/

    string public name;

    string public symbol;

    uint8 public immutable decimals;

    /*//////////////////////////////////////////////////////////////
                              ERC20 STORAGE
    //////////////////////////////////////////////////////////////*/

    uint256 public totalSupply;

    mapping(address => uint256) public balanceOf;

    mapping(address => mapping(address => uint256)) public allowance;

    /*//////////////////////////////////////////////////////////////
                            EIP-2612 STORAGE
    //////////////////////////////////////////////////////////////*/

    uint256 internal immutable INITIAL_CHAIN_ID;

    bytes32 internal immutable INITIAL_DOMAIN_SEPARATOR;

    mapping(address => uint256) public nonces;

    /*//////////////////////////////////////////////////////////////
                               CONSTRUCTOR
    //////////////////////////////////////////////////////////////*/

    constructor(
        string memory _name,
        string memory _symbol,
        uint8 _decimals
    ) {
        name = _name;
        symbol = _symbol;
        decimals = _decimals;

        INITIAL_CHAIN_ID = block.chainid;
        INITIAL_DOMAIN_SEPARATOR = computeDomainSeparator();
    }

    /*//////////////////////////////////////////////////////////////
                               ERC20 LOGIC
    //////////////////////////////////////////////////////////////*/

    function approve(address spender, uint256 amount) public virtual returns (bool) {
        allowance[msg.sender][spender] = amount;

        emit Approval(msg.sender, spender, amount);

        return true;
    }

    function transfer(address to, uint256 amount) public virtual returns (bool) {
        balanceOf[msg.sender] -= amount;

        // Cannot overflow because the sum of all user
        // balances can't exceed the max uint256 value.
        unchecked {
            balanceOf[to] += amount;
        }

        emit Transfer(msg.sender, to, amount);

        return true;
    }

    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual returns (bool) {
        uint256 allowed = allowance[from][msg.sender]; // Saves gas for limited approvals.

        if (allowed != type(uint256).max) allowance[from][msg.sender] = allowed - amount;

        balanceOf[from] -= amount;

        // Cannot overflow because the sum of all user
        // balances can't exceed the max uint256 value.
        unchecked {
            balanceOf[to] += amount;
        }

        emit Transfer(from, to, amount);

        return true;
    }

    /*//////////////////////////////////////////////////////////////
                             EIP-2612 LOGIC
    //////////////////////////////////////////////////////////////*/

    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) public virtual {
        require(deadline >= block.timestamp, "PERMIT_DEADLINE_EXPIRED");

        // Unchecked because the only math done is incrementing
        // the owner's nonce which cannot realistically overflow.
        unchecked {
            address recoveredAddress = ecrecover(
                keccak256(
                    abi.encodePacked(
                        "\x19\x01",
                        DOMAIN_SEPARATOR(),
                        keccak256(
                            abi.encode(
                                keccak256(
                                    "Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)"
                                ),
                                owner,
                                spender,
                                value,
                                nonces[owner]++,
                                deadline
                            )
                        )
                    )
                ),
                v,
                r,
                s
            );

            require(recoveredAddress != address(0) && recoveredAddress == owner, "INVALID_SIGNER");

            allowance[recoveredAddress][spender] = value;
        }

        emit Approval(owner, spender, value);
    }

    function DOMAIN_SEPARATOR() public view virtual returns (bytes32) {
        return block.chainid == INITIAL_CHAIN_ID ? INITIAL_DOMAIN_SEPARATOR : computeDomainSeparator();
    }

    function computeDomainSeparator() internal view virtual returns (bytes32) {
        return
            keccak256(
                abi.encode(
                    keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
                    keccak256(bytes(name)),
                    keccak256("1"),
                    block.chainid,
                    address(this)
                )
            );
    }

    /*//////////////////////////////////////////////////////////////
                        INTERNAL MINT/BURN LOGIC
    //////////////////////////////////////////////////////////////*/

    function _mint(address to, uint256 amount) internal virtual {
        totalSupply += amount;

        // Cannot overflow because the sum of all user
        // balances can't exceed the max uint256 value.
        unchecked {
            balanceOf[to] += amount;
        }

        emit Transfer(address(0), to, amount);
    }

    function _burn(address from, uint256 amount) internal virtual {
        balanceOf[from] -= amount;

        // Cannot underflow because a user's balance
        // will never be larger than the total supply.
        unchecked {
            totalSupply -= amount;
        }

        emit Transfer(from, address(0), amount);
    }
}

// File: lib/clones-with-immutable-args/src/ClonesWithImmutableArgs.sol



// SPDX-License-Identifier: BSD

pragma solidity ^0.8.4;

/// @title ClonesWithImmutableArgs
/// @author wighawag, zefram.eth
/// @notice Enables creating clone contracts with immutable args
library ClonesWithImmutableArgs {
    error CreateFail();

    /// @notice Creates a clone proxy of the implementation contract, with immutable args
    /// @dev data cannot exceed 65535 bytes, since 2 bytes are used to store the data length
    /// @param implementation The implementation contract to clone
    /// @param data Encoded immutable args
    /// @return instance The address of the created clone
    function clone(address implementation, bytes memory data)
        internal
        returns (address instance)
    {
        // unrealistic for memory ptr or data length to exceed 256 bits
        unchecked {
            uint256 extraLength = data.length + 2; // +2 bytes for telling how much data there is appended to the call
            uint256 creationSize = 0x43 + extraLength;
            uint256 runSize = creationSize - 11;
            uint256 dataPtr;
            uint256 ptr;
            // solhint-disable-next-line no-inline-assembly
            assembly {
                ptr := mload(0x40)

                // -------------------------------------------------------------------------------------------------------------
                // CREATION (11 bytes)
                // -------------------------------------------------------------------------------------------------------------

                // 3d          | RETURNDATASIZE        | 0                       | –
                // 61 runtime  | PUSH2 runtime (r)     | r 0                     | –
                mstore(
                    ptr,
                    0x3d61000000000000000000000000000000000000000000000000000000000000
                )
                mstore(add(ptr, 0x02), shl(240, runSize)) // size of the contract running bytecode (16 bits)

                // creation size = 0b
                // 80          | DUP1                  | r r 0                   | –
                // 60 creation | PUSH1 creation (c)    | c r r 0                 | –
                // 3d          | RETURNDATASIZE        | 0 c r r 0               | –
                // 39          | CODECOPY              | r 0                     | [0-2d]: runtime code
                // 81          | DUP2                  | 0 c  0                  | [0-2d]: runtime code
                // f3          | RETURN                | 0                       | [0-2d]: runtime code
                mstore(
                    add(ptr, 0x04),
                    0x80600b3d3981f300000000000000000000000000000000000000000000000000
                )

                // -------------------------------------------------------------------------------------------------------------
                // RUNTIME
                // -------------------------------------------------------------------------------------------------------------

                // 36          | CALLDATASIZE          | cds                     | –
                // 3d          | RETURNDATASIZE        | 0 cds                   | –
                // 3d          | RETURNDATASIZE        | 0 0 cds                 | –
                // 37          | CALLDATACOPY          | –                       | [0, cds] = calldata
                // 61          | PUSH2 extra           | extra                   | [0, cds] = calldata
                mstore(
                    add(ptr, 0x0b),
                    0x363d3d3761000000000000000000000000000000000000000000000000000000
                )
                mstore(add(ptr, 0x10), shl(240, extraLength))

                // 60 0x38     | PUSH1 0x38            | 0x38 extra              | [0, cds] = calldata // 0x38 (56) is runtime size - data
                // 36          | CALLDATASIZE          | cds 0x38 extra          | [0, cds] = calldata
                // 39          | CODECOPY              | _                       | [0, cds] = calldata
                // 3d          | RETURNDATASIZE        | 0                       | [0, cds] = calldata
                // 3d          | RETURNDATASIZE        | 0 0                     | [0, cds] = calldata
                // 3d          | RETURNDATASIZE        | 0 0 0                   | [0, cds] = calldata
                // 36          | CALLDATASIZE          | cds 0 0 0               | [0, cds] = calldata
                // 61 extra    | PUSH2 extra           | extra cds 0 0 0         | [0, cds] = calldata
                mstore(
                    add(ptr, 0x12),
                    0x603836393d3d3d36610000000000000000000000000000000000000000000000
                )
                mstore(add(ptr, 0x1b), shl(240, extraLength))

                // 01          | ADD                   | cds+extra 0 0 0         | [0, cds] = calldata
                // 3d          | RETURNDATASIZE        | 0 cds 0 0 0             | [0, cds] = calldata
                // 73 addr     | PUSH20 0x123…         | addr 0 cds 0 0 0        | [0, cds] = calldata
                mstore(
                    add(ptr, 0x1d),
                    0x013d730000000000000000000000000000000000000000000000000000000000
                )
                mstore(add(ptr, 0x20), shl(0x60, implementation))

                // 5a          | GAS                   | gas addr 0 cds 0 0 0    | [0, cds] = calldata
                // f4          | DELEGATECALL          | success 0               | [0, cds] = calldata
                // 3d          | RETURNDATASIZE        | rds success 0           | [0, cds] = calldata
                // 82          | DUP3                  | 0 rds success 0         | [0, cds] = calldata
                // 80          | DUP1                  | 0 0 rds success 0       | [0, cds] = calldata
                // 3e          | RETURNDATACOPY        | success 0               | [0, rds] = return data (there might be some irrelevant leftovers in memory [rds, cds] when rds < cds)
                // 90          | SWAP1                 | 0 success               | [0, rds] = return data
                // 3d          | RETURNDATASIZE        | rds 0 success           | [0, rds] = return data
                // 91          | SWAP2                 | success 0 rds           | [0, rds] = return data
                // 60 0x36     | PUSH1 0x36            | 0x36 sucess 0 rds       | [0, rds] = return data
                // 57          | JUMPI                 | 0 rds                   | [0, rds] = return data
                // fd          | REVERT                | –                       | [0, rds] = return data
                // 5b          | JUMPDEST              | 0 rds                   | [0, rds] = return data
                // f3          | RETURN                | –                       | [0, rds] = return data

                mstore(
                    add(ptr, 0x34),
                    0x5af43d82803e903d91603657fd5bf30000000000000000000000000000000000
                )
            }

            // -------------------------------------------------------------------------------------------------------------
            // APPENDED DATA (Accessible from extcodecopy)
            // (but also send as appended data to the delegatecall)
            // -------------------------------------------------------------------------------------------------------------

            extraLength -= 2;
            uint256 counter = extraLength;
            uint256 copyPtr = ptr + 0x43;
            // solhint-disable-next-line no-inline-assembly
            assembly {
                dataPtr := add(data, 32)
            }
            for (; counter >= 32; counter -= 32) {
                // solhint-disable-next-line no-inline-assembly
                assembly {
                    mstore(copyPtr, mload(dataPtr))
                }

                copyPtr += 32;
                dataPtr += 32;
            }
            uint256 mask = ~(256**(32 - counter) - 1);
            // solhint-disable-next-line no-inline-assembly
            assembly {
                mstore(copyPtr, and(mload(dataPtr), mask))
            }
            copyPtr += counter;
            // solhint-disable-next-line no-inline-assembly
            assembly {
                mstore(copyPtr, shl(240, extraLength))
            }
            // solhint-disable-next-line no-inline-assembly
            assembly {
                instance := create(0, ptr, creationSize)
            }
            if (instance == address(0)) {
                revert CreateFail();
            }
        }
    }
}

// File: lib/Cooler/src/Cooler.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.15;

import {SafeTransferLib} from "solmate/utils/SafeTransferLib.sol";
import {ERC20} from "solmate/tokens/ERC20.sol";
import {Clone} from "clones/Clone.sol";

// Function sig taken from gOHM contract
interface IDelegate {
    function delegate(address to_) external;
}

import {CoolerFactory} from "./CoolerFactory.sol";
import {CoolerCallback} from "./CoolerCallback.sol";

/// @title  Cooler Loans.
/// @notice A Cooler is a smart contract escrow that facilitates fixed-duration, peer-to-peer
///         loans for a user-defined debt-collateral pair.
/// @dev    This contract uses Clones (https://github.com/wighawag/clones-with-immutable-args)
///         to save gas on deployment.
contract Cooler is Clone {
    using SafeTransferLib for ERC20;

    // --- ERRORS ----------------------------------------------------

    error OnlyApproved();
    error Deactivated();
    error Default();
    error NotExpired();
    error NotCoolerCallback();

    // --- DATA STRUCTURES -------------------------------------------

    /// @notice A loan begins with a borrow request.
    struct Request {
        uint256 amount; // Amount to be borrowed.
        uint256 interest; // Annualized percentage to be paid as interest.
        uint256 loanToCollateral; // Requested loan-to-collateral ratio.
        uint256 duration; // Time to repay the loan before it defaults.
        bool active; // Any lender can clear an active loan request.
        address requester; // The address that created the request.
    }

    /// @notice A request is converted to a loan when a lender clears it.
    struct Loan {
        Request request; // Loan terms specified in the request.
        uint256 principal; // Amount of principal debt owed to the lender.
        uint256 interestDue; // Interest owed to the lender.
        uint256 collateral; // Amount of collateral pledged.
        uint256 expiry; // Time when the loan defaults.
        address lender; // Lender's address.
        address recipient; // Recipient of repayments.
        bool callback; // If this is true, the lender must inherit CoolerCallback.
    }

    // --- IMMUTABLES ------------------------------------------------

    // This makes the code look prettier.
    uint256 private constant DECIMALS_INTEREST = 1e18;

    /// @notice This address owns the collateral in escrow.
    function owner() public pure returns (address _owner) {
        return _getArgAddress(0x0);
    }

    /// @notice This token is borrowed against.
    function collateral() public pure returns (ERC20 _collateral) {
        return ERC20(_getArgAddress(0x14));
    }

    /// @notice This token is lent.
    function debt() public pure returns (ERC20 _debt) {
        return ERC20(_getArgAddress(0x28));
    }

    /// @notice This contract created the Cooler
    function factory() public pure returns (CoolerFactory _factory) {
        return CoolerFactory(_getArgAddress(0x3c));
    }

    // --- STATE VARIABLES -------------------------------------------

    /// @notice Arrays stores all the loan requests.
    Request[] public requests;

    /// @notice Arrays stores all the granted loans.
    Loan[] public loans;

    /// @notice Facilitates transfer of lender ownership to new addresses
    mapping(uint256 => address) public approvals;

    // --- BORROWER --------------------------------------------------

    /// @notice Request a loan with given parameters.
    ///         Collateral is taken at time of request.
    /// @param  amount_ of debt tokens to borrow.
    /// @param  interest_ to pay (annualized % of 'amount_'). Expressed in DECIMALS_INTEREST.
    /// @param  loanToCollateral_ debt tokens per collateral token pledged. Expressed in 10**collateral().decimals().
    /// @param  duration_ of loan tenure in seconds.
    /// @return reqID of the created request. Equivalent to the index of request in requests[].
    function requestLoan(
        uint256 amount_,
        uint256 interest_,
        uint256 loanToCollateral_,
        uint256 duration_
    ) external returns (uint256 reqID) {
        reqID = requests.length;
        requests.push(
            Request({
                amount: amount_,
                interest: interest_,
                loanToCollateral: loanToCollateral_,
                duration: duration_,
                active: true,
                requester: msg.sender
            })
        );

        // The collateral is taken upfront. Will be escrowed
        // until the loan is repaid or defaulted.
        collateral().safeTransferFrom(
            msg.sender,
            address(this),
            collateralFor(amount_, loanToCollateral_)
        );

        // Log the event.
        factory().logRequestLoan(reqID);
    }

    /// @notice Cancel a loan request and get the collateral back.
    /// @param  reqID_ index of request in requests[].
    function rescindRequest(uint256 reqID_) external {
        if (msg.sender != owner()) revert OnlyApproved();

        Request storage req = requests[reqID_];

        if (!req.active) revert Deactivated();

        // Update storage and send collateral back to the owner.
        req.active = false;
        collateral().safeTransfer(owner(), collateralFor(req.amount, req.loanToCollateral));

        // Log the event.
        factory().logRescindRequest(reqID_);
    }

    /// @notice Repay a loan to get the collateral back.
    /// @dev    Despite a malicious lender could reenter with the callback, the
    ///         usage of `msg.sender` prevents any economical benefit to the
    ///         attacker, since they would be repaying the loan themselves.
    /// @param  loanID_ index of loan in loans[].
    /// @param  repayment_ debt tokens to be repaid.
    /// @return collateral given back to the borrower.
    function repayLoan(uint256 loanID_, uint256 repayment_) external returns (uint256) {
        Loan memory loan = loans[loanID_];

        if (block.timestamp > loan.expiry) revert Default();

        // Cap the repayment to the total debt of the loan
        uint256 totalDebt = loan.principal + loan.interestDue;
        if (repayment_ > totalDebt) repayment_ = totalDebt;

        // Need to repay interest first, then any extra goes to paying down principal.
        uint256 interestPaid;
        uint256 remainder;
        if (repayment_ >= loan.interestDue) {
            remainder = repayment_ - loan.interestDue;
            interestPaid = loan.interestDue;
            loan.interestDue = 0;
        } else {
            loan.interestDue -= repayment_;
            interestPaid = repayment_;
        }

        // We pay back only if user has paid back principal. This can be 0.
        uint256 decollateralized;
        if (remainder > 0) {
            decollateralized = (loan.collateral * remainder) / loan.principal;

            loan.principal -= remainder;
            loan.collateral -= decollateralized;
        }

        // Save updated loan info in storage.
        loans[loanID_] = loan;

        // Transfer repaid debt back to the lender and collateral back to the owner if applicable
        debt().safeTransferFrom(msg.sender, loan.recipient, repayment_);
        if (decollateralized > 0) collateral().safeTransfer(owner(), decollateralized);

        // Log the event.
        factory().logRepayLoan(loanID_, repayment_);

        // If necessary, trigger lender callback.
        if (loan.callback) CoolerCallback(loan.lender).onRepay(loanID_, remainder, interestPaid);

        return decollateralized;
    }

    /// @notice Delegate voting power on collateral.
    /// @param  to_ address to delegate.
    function delegateVoting(address to_) external {
        if (msg.sender != owner()) revert OnlyApproved();
        IDelegate(address(collateral())).delegate(to_);
    }

    // --- LENDER ----------------------------------------------------

    /// @notice Fill a requested loan as a lender.
    /// @param  reqID_ index of request in requests[].
    /// @param  recipient_ address to repay the loan to.
    /// @param  isCallback_ true if the lender implements the CoolerCallback abstract. False otherwise.
    /// @return loanID of the granted loan. Equivalent to the index of loan in loans[].
    function clearRequest(
        uint256 reqID_,
        address recipient_,
        bool isCallback_
    ) external returns (uint256 loanID) {
        Request memory req = requests[reqID_];

        // Loan callbacks are only allowed if:
        //  1. The loan request has been created via a trusted lender.
        //  2. The lender signals that it implements the CoolerCallback Abstract.
        bool callback = (isCallback_ && msg.sender == req.requester);

        // If necessary, ensure lender implements the CoolerCallback abstract.
        if (callback && !CoolerCallback(msg.sender).isCoolerCallback()) revert NotCoolerCallback();
        // Ensure loan request is active.
        if (!req.active) revert Deactivated();

        // Clear the loan request in memory.
        req.active = false;

        // Calculate and store loan terms.
        uint256 interest = interestFor(req.amount, req.interest, req.duration);
        uint256 collat = collateralFor(req.amount, req.loanToCollateral);
        loanID = loans.length;

        loans.push(
            Loan({
                request: req,
                principal: req.amount,
                interestDue: interest,
                collateral: collat,
                expiry: block.timestamp + req.duration,
                lender: msg.sender,
                recipient: recipient_,
                callback: callback
            })
        );

        // Clear the loan request storage.
        requests[reqID_].active = false;

        // Transfer debt tokens to the owner of the request.
        debt().safeTransferFrom(msg.sender, owner(), req.amount);

        // Log the event.
        factory().logClearRequest(reqID_, loanID);
    }

    /// @notice Allow lender to extend a loan for the borrower. Doesn't require
    ///         borrower permission because it doesn't have a negative impact for them.
    /// @dev    Since this function solely impacts the expiration day, the lender
    ///         should ensure that extension interest payments are done beforehand.
    /// @param  loanID_ index of loan in loans[].
    /// @param  times_ that the fixed-term loan duration is extended.
    function extendLoanTerms(uint256 loanID_, uint8 times_) external {
        Loan memory loan = loans[loanID_];

        if (msg.sender != loan.lender) revert OnlyApproved();
        if (block.timestamp > loan.expiry) revert Default();

        // Update loan terms to reflect the extension.
        loan.expiry += loan.request.duration * times_;

        // Save updated loan info in storage.
        loans[loanID_] = loan;

        // Log the event.
        factory().logExtendLoan(loanID_, times_);
    }

    /// @notice Claim collateral upon loan default.
    /// @param  loanID_ index of loan in loans[].
    /// @return defaulted debt by the borrower, collateral kept by the lender, elapsed time since expiry.
    function claimDefaulted(uint256 loanID_) external returns (uint256, uint256, uint256, uint256) {
        Loan memory loan = loans[loanID_];

        if (block.timestamp <= loan.expiry) revert NotExpired();

        loans[loanID_].principal = 0;
        loans[loanID_].interestDue = 0;
        loans[loanID_].collateral = 0;

        // Transfer defaulted collateral to the lender.
        collateral().safeTransfer(loan.lender, loan.collateral);

        // Log the event.
        factory().logDefaultLoan(loanID_, loan.collateral);

        // If necessary, trigger lender callback.
        if (loan.callback)
            CoolerCallback(loan.lender).onDefault(
                loanID_,
                loan.principal,
                loan.interestDue,
                loan.collateral
            );

        return (loan.principal, loan.interestDue, loan.collateral, block.timestamp - loan.expiry);
    }

    /// @notice Approve transfer of loan ownership rights to a new address.
    /// @param  to_ address to be approved.
    /// @param  loanID_ index of loan in loans[].
    function approveTransfer(address to_, uint256 loanID_) external {
        if (msg.sender != loans[loanID_].lender) revert OnlyApproved();

        // Update transfer approvals.
        approvals[loanID_] = to_;
    }

    /// @notice Execute loan ownership transfer. Must be previously approved by the lender.
    /// @param  loanID_ index of loan in loans[].
    function transferOwnership(uint256 loanID_) external {
        if (msg.sender != approvals[loanID_]) revert OnlyApproved();

        // Update the load lender and the recipient.
        loans[loanID_].lender = msg.sender;
        loans[loanID_].recipient = msg.sender;
        // Callbacks are disabled when transferring ownership.
        loans[loanID_].callback = false;
        // Clear transfer approvals.
        approvals[loanID_] = address(0);
    }

    /// @notice Allow lender to set repayment recipient of a given loan.
    /// @param  loanID_ of lender's loan.
    /// @param  recipient_ reciever of repayments
    function setRepaymentAddress(uint256 loanID_, address recipient_) external {
        if (msg.sender != loans[loanID_].lender) revert OnlyApproved();

        // Update the repayment method.
        loans[loanID_].recipient = recipient_;
    }

    // --- AUX FUNCTIONS ---------------------------------------------

    /// @notice Compute collateral needed for a desired loan amount at given loan to collateral ratio.
    /// @param  principal_ amount of debt tokens.
    /// @param  loanToCollateral_ ratio for loan. Expressed in 10**collateral().decimals().
    function collateralFor(
        uint256 principal_,
        uint256 loanToCollateral_
    ) public view returns (uint256) {
        return (principal_ * (10 ** collateral().decimals())) / loanToCollateral_;
    }

    /// @notice Compute interest cost on amount for duration at given annualized rate.
    /// @param  principal_ amount of debt tokens.
    /// @param  rate_ of interest (annualized).
    /// @param  duration_ of the loan in seconds.
    /// @return Interest in debt token terms.
    function interestFor(
        uint256 principal_,
        uint256 rate_,
        uint256 duration_
    ) public pure returns (uint256) {
        uint256 interest = (rate_ * duration_) / 365 days;
        return (principal_ * interest) / DECIMALS_INTEREST;
    }

    /// @notice Check if given loan has expired.
    /// @param  loanID_ index of loan in loans[].
    /// @return Expiration status.
    function hasExpired(uint256 loanID_) external view returns (bool) {
        return block.timestamp > loans[loanID_].expiry;
    }

    /// @notice Check if a given request is active.
    /// @param  reqID_ index of request in requests[].
    /// @return Active status.
    function isActive(uint256 reqID_) external view returns (bool) {
        return requests[reqID_].active;
    }

    /// @notice Getter for Request data as a struct.
    /// @param  reqID_ index of request in requests[].
    /// @return Request struct.
    function getRequest(uint256 reqID_) external view returns (Request memory) {
        return requests[reqID_];
    }

    /// @notice Getter for Loan data as a struct.
    /// @param loanID_ index of loan in loans[].
    /// @return Loan struct.
    function getLoan(uint256 loanID_) external view returns (Loan memory) {
        return loans[loanID_];
    }
}

// File: lib/solmate/src/utils/SafeTransferLib.sol



// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity >=0.8.0;

import {ERC20} from "../tokens/ERC20.sol";

/// @notice Safe ETH and ERC20 transfer library that gracefully handles missing return values.
/// @author Solmate (https://github.com/transmissions11/solmate/blob/main/src/utils/SafeTransferLib.sol)
/// @dev Use with caution! Some functions in this library knowingly create dirty bits at the destination of the free memory pointer.
/// @dev Note that none of the functions in this library check that a token has code at all! That responsibility is delegated to the caller.
library SafeTransferLib {
    /*//////////////////////////////////////////////////////////////
                             ETH OPERATIONS
    //////////////////////////////////////////////////////////////*/

    function safeTransferETH(address to, uint256 amount) internal {
        bool success;

        /// @solidity memory-safe-assembly
        assembly {
            // Transfer the ETH and store if it succeeded or not.
            success := call(gas(), to, amount, 0, 0, 0, 0)
        }

        require(success, "ETH_TRANSFER_FAILED");
    }

    /*//////////////////////////////////////////////////////////////
                            ERC20 OPERATIONS
    //////////////////////////////////////////////////////////////*/

    function safeTransferFrom(
        ERC20 token,
        address from,
        address to,
        uint256 amount
    ) internal {
        bool success;

        /// @solidity memory-safe-assembly
        assembly {
            // Get a pointer to some free memory.
            let freeMemoryPointer := mload(0x40)

            // Write the abi-encoded calldata into memory, beginning with the function selector.
            mstore(freeMemoryPointer, 0x23b872dd00000000000000000000000000000000000000000000000000000000)
            mstore(add(freeMemoryPointer, 4), and(from, 0xffffffffffffffffffffffffffffffffffffffff)) // Append and mask the "from" argument.
            mstore(add(freeMemoryPointer, 36), and(to, 0xffffffffffffffffffffffffffffffffffffffff)) // Append and mask the "to" argument.
            mstore(add(freeMemoryPointer, 68), amount) // Append the "amount" argument. Masking not required as it's a full 32 byte type.

            success := and(
                // Set success to whether the call reverted, if not we check it either
                // returned exactly 1 (can't just be non-zero data), or had no return data.
                or(and(eq(mload(0), 1), gt(returndatasize(), 31)), iszero(returndatasize())),
                // We use 100 because the length of our calldata totals up like so: 4 + 32 * 3.
                // We use 0 and 32 to copy up to 32 bytes of return data into the scratch space.
                // Counterintuitively, this call must be positioned second to the or() call in the
                // surrounding and() call or else returndatasize() will be zero during the computation.
                call(gas(), token, 0, freeMemoryPointer, 100, 0, 32)
            )
        }

        require(success, "TRANSFER_FROM_FAILED");
    }

    function safeTransfer(
        ERC20 token,
        address to,
        uint256 amount
    ) internal {
        bool success;

        /// @solidity memory-safe-assembly
        assembly {
            // Get a pointer to some free memory.
            let freeMemoryPointer := mload(0x40)

            // Write the abi-encoded calldata into memory, beginning with the function selector.
            mstore(freeMemoryPointer, 0xa9059cbb00000000000000000000000000000000000000000000000000000000)
            mstore(add(freeMemoryPointer, 4), and(to, 0xffffffffffffffffffffffffffffffffffffffff)) // Append and mask the "to" argument.
            mstore(add(freeMemoryPointer, 36), amount) // Append the "amount" argument. Masking not required as it's a full 32 byte type.

            success := and(
                // Set success to whether the call reverted, if not we check it either
                // returned exactly 1 (can't just be non-zero data), or had no return data.
                or(and(eq(mload(0), 1), gt(returndatasize(), 31)), iszero(returndatasize())),
                // We use 68 because the length of our calldata totals up like so: 4 + 32 * 2.
                // We use 0 and 32 to copy up to 32 bytes of return data into the scratch space.
                // Counterintuitively, this call must be positioned second to the or() call in the
                // surrounding and() call or else returndatasize() will be zero during the computation.
                call(gas(), token, 0, freeMemoryPointer, 68, 0, 32)
            )
        }

        require(success, "TRANSFER_FAILED");
    }

    function safeApprove(
        ERC20 token,
        address to,
        uint256 amount
    ) internal {
        bool success;

        /// @solidity memory-safe-assembly
        assembly {
            // Get a pointer to some free memory.
            let freeMemoryPointer := mload(0x40)

            // Write the abi-encoded calldata into memory, beginning with the function selector.
            mstore(freeMemoryPointer, 0x095ea7b300000000000000000000000000000000000000000000000000000000)
            mstore(add(freeMemoryPointer, 4), and(to, 0xffffffffffffffffffffffffffffffffffffffff)) // Append and mask the "to" argument.
            mstore(add(freeMemoryPointer, 36), amount) // Append the "amount" argument. Masking not required as it's a full 32 byte type.

            success := and(
                // Set success to whether the call reverted, if not we check it either
                // returned exactly 1 (can't just be non-zero data), or had no return data.
                or(and(eq(mload(0), 1), gt(returndatasize(), 31)), iszero(returndatasize())),
                // We use 68 because the length of our calldata totals up like so: 4 + 32 * 2.
                // We use 0 and 32 to copy up to 32 bytes of return data into the scratch space.
                // Counterintuitively, this call must be positioned second to the or() call in the
                // surrounding and() call or else returndatasize() will be zero during the computation.
                call(gas(), token, 0, freeMemoryPointer, 68, 0, 32)
            )
        }

        require(success, "APPROVE_FAILED");
    }
}

// File: lib/clones-with-immutable-args/src/Clone.sol



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

/// @title Clone
/// @author zefram.eth
/// @notice Provides helper functions for reading immutable args from calldata
contract Clone {
    /// @notice Reads an immutable arg with type address
    /// @param argOffset The offset of the arg in the packed data
    /// @return arg The arg value
    function _getArgAddress(uint256 argOffset)
        internal
        pure
        returns (address arg)
    {
        uint256 offset = _getImmutableArgsOffset();
        assembly {
            arg := shr(0x60, calldataload(add(offset, argOffset)))
        }
    }

    /// @notice Reads an immutable arg with type uint256
    /// @param argOffset The offset of the arg in the packed data
    /// @return arg The arg value
    function _getArgUint256(uint256 argOffset)
        internal
        pure
        returns (uint256 arg)
    {
        uint256 offset = _getImmutableArgsOffset();
        // solhint-disable-next-line no-inline-assembly
        assembly {
            arg := calldataload(add(offset, argOffset))
        }
    }

    /// @notice Reads an immutable arg with type uint64
    /// @param argOffset The offset of the arg in the packed data
    /// @return arg The arg value
    function _getArgUint64(uint256 argOffset)
        internal
        pure
        returns (uint64 arg)
    {
        uint256 offset = _getImmutableArgsOffset();
        // solhint-disable-next-line no-inline-assembly
        assembly {
            arg := shr(0xc0, calldataload(add(offset, argOffset)))
        }
    }

    /// @notice Reads an immutable arg with type uint8
    /// @param argOffset The offset of the arg in the packed data
    /// @return arg The arg value
    function _getArgUint8(uint256 argOffset) internal pure returns (uint8 arg) {
        uint256 offset = _getImmutableArgsOffset();
        // solhint-disable-next-line no-inline-assembly
        assembly {
            arg := shr(0xf8, calldataload(add(offset, argOffset)))
        }
    }

    /// @return offset The offset of the packed immutable args in calldata
    function _getImmutableArgsOffset() internal pure returns (uint256 offset) {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            offset := sub(
                calldatasize(),
                add(shr(240, calldataload(sub(calldatasize(), 2))), 2)
            )
        }
    }
}

// File: lib/Cooler/src/CoolerCallback.sol



// SPDX-License-Identifier: MIT
pragma solidity >=0.8.0;

import {CoolerFactory} from "./CoolerFactory.sol";

/// @notice Allows for debt issuers to execute logic when a loan is repaid, rolled, or defaulted.
/// @dev    The three callback functions must be implemented if `isCoolerCallback()` is set to true.
abstract contract CoolerCallback {
    // --- ERRORS ----------------------------------------------------

    error OnlyFromFactory();

    // --- INITIALIZATION --------------------------------------------

    CoolerFactory public immutable factory;

    constructor(address coolerFactory_) {
        factory = CoolerFactory(coolerFactory_);
    }

    // --- EXTERNAL FUNCTIONS ------------------------------------------------

    /// @notice Informs to Cooler that this contract can handle its callbacks.
    function isCoolerCallback() external pure returns (bool) {
        return true;
    }

    /// @notice Callback function that handles repayments.
    function onRepay(uint256 loanID_, uint256 principlePaid_, uint256 interestPaid_) external {
        if (!factory.created(msg.sender)) revert OnlyFromFactory();
        _onRepay(loanID_, principlePaid_, interestPaid_);
    }

    /// @notice Callback function that handles defaults.
    function onDefault(
        uint256 loanID_,
        uint256 principle,
        uint256 interest,
        uint256 collateral
    ) external {
        if (!factory.created(msg.sender)) revert OnlyFromFactory();
        _onDefault(loanID_, principle, interest, collateral);
    }

    // --- INTERNAL FUNCTIONS ------------------------------------------------

    /// @notice Callback function that handles repayments. Override for custom logic.
    function _onRepay(
        uint256 loanID_,
        uint256 principlePaid_,
        uint256 interestPaid_
    ) internal virtual;

    /// @notice Callback function that handles defaults.
    function _onDefault(
        uint256 loanID_,
        uint256 principle_,
        uint256 interestDue_,
        uint256 collateral
    ) internal virtual;
}