// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/Address.sol)

pragma solidity ^0.8.20;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev The ETH balance of the account is not enough to perform the operation.
     */
    error AddressInsufficientBalance(address account);

    /**
     * @dev There's no code at `target` (it is not a contract).
     */
    error AddressEmptyCode(address target);

    /**
     * @dev A call to an address target failed. The target may have reverted.
     */
    error FailedInnerCall();

    /**
     * @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/v0.8.20/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        if (address(this).balance < amount) {
            revert AddressInsufficientBalance(address(this));
        }

        (bool success, ) = recipient.call{value: amount}("");
        if (!success) {
            revert FailedInnerCall();
        }
    }

    /**
     * @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 or custom error, it is bubbled
     * up by this function (like regular Solidity function calls). However, if
     * the call reverted with no returned reason, this function reverts with a
     * {FailedInnerCall} error.
     *
     * 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.
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0);
    }

    /**
     * @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`.
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        if (address(this).balance < value) {
            revert AddressInsufficientBalance(address(this));
        }
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and reverts if the target
     * was not a contract or bubbling up the revert reason (falling back to {FailedInnerCall}) in case of an
     * unsuccessful call.
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata
    ) internal view returns (bytes memory) {
        if (!success) {
            _revert(returndata);
        } else {
            // only check if target is a contract if the call was successful and the return data is empty
            // otherwise we already know that it was a contract
            if (returndata.length == 0 && target.code.length == 0) {
                revert AddressEmptyCode(target);
            }
            return returndata;
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and reverts if it wasn't, either by bubbling the
     * revert reason or with a default {FailedInnerCall} error.
     */
    function verifyCallResult(bool success, bytes memory returndata) internal pure returns (bytes memory) {
        if (!success) {
            _revert(returndata);
        } else {
            return returndata;
        }
    }

    /**
     * @dev Reverts with returndata if present. Otherwise reverts with {FailedInnerCall}.
     */
    function _revert(bytes memory returndata) 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 FailedInnerCall();
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.20;

/**
 * @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 value of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

    /**
     * @dev Moves a `value` amount of 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 value) 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 a `value` amount of tokens 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 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the
     * allowance mechanism. `value` 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 value) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/extensions/IERC20Permit.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 *
 * ==== Security Considerations
 *
 * There are two important considerations concerning the use of `permit`. The first is that a valid permit signature
 * expresses an allowance, and it should not be assumed to convey additional meaning. In particular, it should not be
 * considered as an intention to spend the allowance in any specific way. The second is that because permits have
 * built-in replay protection and can be submitted by anyone, they can be frontrun. A protocol that uses permits should
 * take this into consideration and allow a `permit` call to fail. Combining these two aspects, a pattern that may be
 * generally recommended is:
 *
 * ```solidity
 * function doThingWithPermit(..., uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) public {
 *     try token.permit(msg.sender, address(this), value, deadline, v, r, s) {} catch {}
 *     doThing(..., value);
 * }
 *
 * function doThing(..., uint256 value) public {
 *     token.safeTransferFrom(msg.sender, address(this), value);
 *     ...
 * }
 * ```
 *
 * Observe that: 1) `msg.sender` is used as the owner, leaving no ambiguity as to the signer intent, and 2) the use of
 * `try/catch` allows the permit to fail and makes the code tolerant to frontrunning. (See also
 * {SafeERC20-safeTransferFrom}).
 *
 * Additionally, note that smart contract wallets (such as Argent or Safe) are not able to produce permit signatures, so
 * contracts should have entry points that don't rely on permit.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     *
     * CAUTION: See Security Considerations above.
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.20;

interface ILockFactory {
    function getInitFeeDistributor() external view returns (address);
    function getInitTokenLocker()
        external
        view
        returns (address, uint256, uint256);
    function createLock(
        address pair,
        uint256 lockerFeesP
    ) external returns (address);
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.20;

interface IPair {
    function metadata()
        external
        view
        returns (
            uint dec0,
            uint dec1,
            uint r0,
            uint r1,
            bool st,
            address t0,
            address t1
        );
    function claimFees() external returns (uint, uint);
    function tokens() external view returns (address, address);
    function transferFrom(
        address src,
        address dst,
        uint amount
    ) external returns (bool);
    function permit(
        address owner,
        address spender,
        uint value,
        uint deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;
    function swap(
        uint amount0Out,
        uint amount1Out,
        address to,
        bytes calldata data
    ) external;
    function burn(address to) external returns (uint amount0, uint amount1);
    function mint(address to) external returns (uint liquidity);
    function getReserves()
        external
        view
        returns (uint _reserve0, uint _reserve1, uint _blockTimestampLast);
    function getAmountOut(uint, address) external view returns (uint);
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.20;

interface IPairFactory {
    function allPairsLength() external view returns (uint);
    function isPair(address pair) external view returns (bool);
    function pairCodeHash() external pure returns (bytes32);
    function getPair(
        address tokenA,
        address token,
        bool stable
    ) external view returns (address);
    function createPair(
        address tokenA,
        address tokenB,
        bool stable,
        uint256 lockerFeesP,
        address feeDistributor
    ) external returns (address pair);
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.20;

interface IRouter {
    function pairFor(
        address tokenA,
        address tokenB,
        bool stable
    ) external view returns (address pair);
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.20;

interface IWETH {
    function deposit() external payable;
    function transfer(address to, uint256 value) external returns (bool);
    function withdraw(uint256) external;
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.20;

library Math {
    function max(uint a, uint b) internal pure returns (uint) {
        return a >= b ? a : b;
    }

    function min(uint a, uint b) internal pure returns (uint) {
        return a < b ? a : b;
    }

    function sqrt(uint y) internal pure returns (uint z) {
        if (y > 3) {
            z = y;
            uint x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }

    function cbrt(uint256 n) internal pure returns (uint256) {
        unchecked {
            uint256 x = 0;
            for (uint256 y = 1 << 255; y > 0; y >>= 3) {
                x <<= 1;
                uint256 z = 3 * x * (x + 1) + 1;
                if (n / y >= z) {
                    n -= y * z;
                    x += 1;
                }
            }
            return x;
        }
    }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.8.20;

import "contracts/libraries/Math.sol";
import "contracts/interfaces/IPair.sol";
import "contracts/interfaces/IPairFactory.sol";
import "contracts/interfaces/ILockFactory.sol";
import "contracts/interfaces/IRouter.sol";
import "contracts/interfaces/IWETH.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

contract Router is IRouter {
    using SafeERC20 for IERC20;
    struct route {
        address from;
        address to;
        bool stable;
    }

    address public immutable factory;
    ILockFactory public immutable lockFactory;
    IWETH public immutable weth;
    uint internal constant MINIMUM_LIQUIDITY = 10 ** 3;
    bytes32 immutable pairCodeHash;

    modifier ensure(uint deadline) {
        require(deadline >= block.timestamp, "Router: EXPIRED");
        _;
    }

    constructor(address _factory, ILockFactory _lockFactory, address _weth) {
        factory = _factory;
        lockFactory = _lockFactory;
        pairCodeHash = IPairFactory(_factory).pairCodeHash();
        weth = IWETH(_weth);
    }

    receive() external payable {
        assert(msg.sender == address(weth)); // only accept ETH via fallback from the WETH contract
    }

    function sortTokens(
        address tokenA,
        address tokenB
    ) public pure returns (address token0, address token1) {
        require(tokenA != tokenB, "Router: IDENTICAL_ADDRESSES");
        (token0, token1) = tokenA < tokenB
            ? (tokenA, tokenB)
            : (tokenB, tokenA);
        require(token0 != address(0), "Router: ZERO_ADDRESS");
    }

    // calculates the CREATE2 address for a pair without making any external calls
    function pairFor(
        address tokenA,
        address tokenB,
        bool stable
    ) public view returns (address pair) {
        (address token0, address token1) = sortTokens(tokenA, tokenB);
        pair = address(
            uint160(
                uint256(
                    keccak256(
                        abi.encodePacked(
                            hex"ff",
                            factory,
                            keccak256(abi.encodePacked(token0, token1, stable)),
                            pairCodeHash // init code hash
                        )
                    )
                )
            )
        );
    }

    // given some amount of an asset and pair reserves, returns an equivalent amount of the other asset
    function quoteLiquidity(
        uint amountA,
        uint reserveA,
        uint reserveB
    ) internal pure returns (uint amountB) {
        require(amountA > 0, "Router: INSUFFICIENT_AMOUNT");
        require(reserveA > 0 && reserveB > 0, "Router: INSUFFICIENT_LIQUIDITY");
        amountB = (amountA * reserveB) / reserveA;
    }

    // fetches and sorts the reserves for a pair
    function getReserves(
        address tokenA,
        address tokenB,
        bool stable
    ) public view returns (uint reserveA, uint reserveB) {
        (address token0, ) = sortTokens(tokenA, tokenB);
        (uint reserve0, uint reserve1, ) = IPair(
            pairFor(tokenA, tokenB, stable)
        ).getReserves();
        (reserveA, reserveB) = tokenA == token0
            ? (reserve0, reserve1)
            : (reserve1, reserve0);
    }

    // performs chained getAmountOut calculations on any number of pairs
    function getAmountOut(
        uint amountIn,
        address tokenIn,
        address tokenOut
    ) external view returns (uint amount, bool stable) {
        address pair = pairFor(tokenIn, tokenOut, true);
        uint amountStable;
        uint amountVolatile;
        if (IPairFactory(factory).isPair(pair)) {
            amountStable = IPair(pair).getAmountOut(amountIn, tokenIn);
        }
        pair = pairFor(tokenIn, tokenOut, false);
        if (IPairFactory(factory).isPair(pair)) {
            amountVolatile = IPair(pair).getAmountOut(amountIn, tokenIn);
        }
        return
            amountStable > amountVolatile
                ? (amountStable, true)
                : (amountVolatile, false);
    }

    // performs chained getAmountOut calculations on any number of pairs
    function getAmountsOut(
        uint amountIn,
        route[] memory routes
    ) public view returns (uint[] memory amounts) {
        require(routes.length >= 1, "Router: INVALID_PATH");
        amounts = new uint[](routes.length + 1);
        amounts[0] = amountIn;
        for (uint i = 0; i < routes.length; i++) {
            address pair = pairFor(
                routes[i].from,
                routes[i].to,
                routes[i].stable
            );
            if (IPairFactory(factory).isPair(pair)) {
                amounts[i + 1] = IPair(pair).getAmountOut(
                    amounts[i],
                    routes[i].from
                );
            }
        }
    }

    function isPair(address pair) external view returns (bool) {
        return IPairFactory(factory).isPair(pair);
    }

    function quoteAddLiquidity(
        address tokenA,
        address tokenB,
        bool stable,
        uint amountADesired,
        uint amountBDesired
    ) external view returns (uint amountA, uint amountB, uint liquidity) {
        // create the pair if it doesn't exist yet
        address _pair = IPairFactory(factory).getPair(tokenA, tokenB, stable);
        (uint reserveA, uint reserveB) = (0, 0);
        uint _totalSupply = 0;
        if (_pair != address(0)) {
            _totalSupply = IERC20(_pair).totalSupply();
            (reserveA, reserveB) = getReserves(tokenA, tokenB, stable);
        }
        if (reserveA == 0 && reserveB == 0) {
            (amountA, amountB) = (amountADesired, amountBDesired);
            liquidity = Math.sqrt(amountA * amountB) - MINIMUM_LIQUIDITY;
        } else {
            uint amountBOptimal = quoteLiquidity(
                amountADesired,
                reserveA,
                reserveB
            );
            if (amountBOptimal <= amountBDesired) {
                (amountA, amountB) = (amountADesired, amountBOptimal);
                liquidity = Math.min(
                    (amountA * _totalSupply) / reserveA,
                    (amountB * _totalSupply) / reserveB
                );
            } else {
                uint amountAOptimal = quoteLiquidity(
                    amountBDesired,
                    reserveB,
                    reserveA
                );
                (amountA, amountB) = (amountAOptimal, amountBDesired);
                liquidity = Math.min(
                    (amountA * _totalSupply) / reserveA,
                    (amountB * _totalSupply) / reserveB
                );
            }
        }
    }

    function quoteRemoveLiquidity(
        address tokenA,
        address tokenB,
        bool stable,
        uint liquidity
    ) external view returns (uint amountA, uint amountB) {
        // create the pair if it doesn't exist yet
        address _pair = IPairFactory(factory).getPair(tokenA, tokenB, stable);

        if (_pair == address(0)) {
            return (0, 0);
        }

        (uint reserveA, uint reserveB) = getReserves(tokenA, tokenB, stable);
        uint _totalSupply = IERC20(_pair).totalSupply();

        amountA = (liquidity * reserveA) / _totalSupply; // using balances ensures pro-rata distribution
        amountB = (liquidity * reserveB) / _totalSupply; // using balances ensures pro-rata distribution
    }

    function _addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        bool stable,
        uint256 lockerFeesP
    ) internal returns (uint amountA, uint amountB) {
        require(amountADesired >= amountAMin);
        require(amountBDesired >= amountBMin);
        // create the pair if it doesn't exist yet
        address _pair = IPairFactory(factory).getPair(tokenA, tokenB, stable);
        if (_pair == address(0)) {
            address feeDistributor;
            if (lockerFeesP > 0) {
                _pair = pairFor(tokenA, tokenB, stable);
                feeDistributor = lockFactory.createLock(_pair, lockerFeesP);
            }
            _pair = IPairFactory(factory).createPair(
                tokenA,
                tokenB,
                stable,
                lockerFeesP,
                feeDistributor
            );
        }
        (uint reserveA, uint reserveB) = getReserves(tokenA, tokenB, stable);
        if (reserveA == 0 && reserveB == 0) {
            (amountA, amountB) = (amountADesired, amountBDesired);
        } else {
            uint amountBOptimal = quoteLiquidity(
                amountADesired,
                reserveA,
                reserveB
            );
            if (amountBOptimal <= amountBDesired) {
                require(
                    amountBOptimal >= amountBMin,
                    "Router: INSUFFICIENT_B_AMOUNT"
                );
                (amountA, amountB) = (amountADesired, amountBOptimal);
            } else {
                uint amountAOptimal = quoteLiquidity(
                    amountBDesired,
                    reserveB,
                    reserveA
                );
                assert(amountAOptimal <= amountADesired);
                require(
                    amountAOptimal >= amountAMin,
                    "Router: INSUFFICIENT_A_AMOUNT"
                );
                (amountA, amountB) = (amountAOptimal, amountBDesired);
            }
        }
    }

    // Add liquidity, if pair doesn't exist then use lockerFeesP for creating a pair.
    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool stable,
        uint256 lockerFeesP
    )
        external
        ensure(deadline)
        returns (uint amountA, uint amountB, uint liquidity)
    {
        (amountA, amountB) = _addLiquidity(
            tokenA,
            tokenB,
            amountADesired,
            amountBDesired,
            amountAMin,
            amountBMin,
            stable,
            lockerFeesP
        );
        address pair = pairFor(tokenA, tokenB, stable);
        _safeTransfer(tokenA, msg.sender, pair, amountA);
        _safeTransfer(tokenB, msg.sender, pair, amountB);
        liquidity = IPair(pair).mint(to);
    }

    // Add ETH liquidity, if pair doesn't exist then use lockerFeesP for creating a pair.
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool stable,
        uint256 lockerFeesP
    )
        external
        payable
        ensure(deadline)
        returns (uint amountToken, uint amountETH, uint liquidity)
    {
        (amountToken, amountETH) = _addLiquidity(
            token,
            address(weth),
            amountTokenDesired,
            msg.value,
            amountTokenMin,
            amountETHMin,
            stable,
            lockerFeesP
        );
        address pair = pairFor(token, address(weth), stable);
        _safeTransfer(token, msg.sender, pair, amountToken);
        weth.deposit{value: amountETH}();
        assert(weth.transfer(pair, amountETH));
        liquidity = IPair(pair).mint(to);
        // refund dust eth, if any
        if (msg.value > amountETH)
            _safeTransferETH(msg.sender, msg.value - amountETH);
    }

    // **** REMOVE LIQUIDITY ****
    function removeLiquidity(
        address tokenA,
        address tokenB,
        bool stable,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) public ensure(deadline) returns (uint amountA, uint amountB) {
        address pair = pairFor(tokenA, tokenB, stable);
        require(IPair(pair).transferFrom(msg.sender, pair, liquidity)); // send liquidity to pair
        (uint amount0, uint amount1) = IPair(pair).burn(to);
        (address token0, ) = sortTokens(tokenA, tokenB);
        (amountA, amountB) = tokenA == token0
            ? (amount0, amount1)
            : (amount1, amount0);
        require(amountA >= amountAMin, "Router: INSUFFICIENT_A_AMOUNT");
        require(amountB >= amountBMin, "Router: INSUFFICIENT_B_AMOUNT");
    }

    function removeLiquidityETH(
        address token,
        bool stable,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) public ensure(deadline) returns (uint amountToken, uint amountETH) {
        (amountToken, amountETH) = removeLiquidity(
            token,
            address(weth),
            stable,
            liquidity,
            amountTokenMin,
            amountETHMin,
            address(this),
            deadline
        );
        _safeTransfer(token, address(this), to, amountToken);
        weth.withdraw(amountETH);
        _safeTransferETH(to, amountETH);
    }

    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        bool stable,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint amountA, uint amountB) {
        address pair = pairFor(tokenA, tokenB, stable);
        {
            uint value = approveMax ? type(uint).max : liquidity;
            IPair(pair).permit(
                msg.sender,
                address(this),
                value,
                deadline,
                v,
                r,
                s
            );
        }

        (amountA, amountB) = removeLiquidity(
            tokenA,
            tokenB,
            stable,
            liquidity,
            amountAMin,
            amountBMin,
            to,
            deadline
        );
    }

    function removeLiquidityETHWithPermit(
        address token,
        bool stable,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint amountToken, uint amountETH) {
        address pair = pairFor(token, address(weth), stable);
        uint value = approveMax ? type(uint).max : liquidity;
        IPair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
        (amountToken, amountETH) = removeLiquidityETH(
            token,
            stable,
            liquidity,
            amountTokenMin,
            amountETHMin,
            to,
            deadline
        );
    }

    // **** SWAP ****
    // requires the initial amount to have already been sent to the first pair
    function _swap(
        uint[] memory amounts,
        route[] memory routes,
        address _to
    ) internal virtual {
        for (uint i = 0; i < routes.length; i++) {
            (address token0, ) = sortTokens(routes[i].from, routes[i].to);
            uint amountOut = amounts[i + 1];
            (uint amount0Out, uint amount1Out) = routes[i].from == token0
                ? (uint(0), amountOut)
                : (amountOut, uint(0));
            address to = i < routes.length - 1
                ? pairFor(
                    routes[i + 1].from,
                    routes[i + 1].to,
                    routes[i + 1].stable
                )
                : _to;
            IPair(pairFor(routes[i].from, routes[i].to, routes[i].stable)).swap(
                amount0Out,
                amount1Out,
                to,
                new bytes(0)
            );
        }
    }

    function swapExactTokensForTokensSimple(
        uint amountIn,
        uint amountOutMin,
        address tokenFrom,
        address tokenTo,
        bool stable,
        address to,
        uint deadline
    ) external ensure(deadline) returns (uint[] memory amounts) {
        route[] memory routes = new route[](1);
        routes[0].from = tokenFrom;
        routes[0].to = tokenTo;
        routes[0].stable = stable;
        amounts = getAmountsOut(amountIn, routes);
        require(
            amounts[amounts.length - 1] >= amountOutMin,
            "Router: INSUFFICIENT_OUTPUT_AMOUNT"
        );
        _safeTransfer(
            routes[0].from,
            msg.sender,
            pairFor(routes[0].from, routes[0].to, routes[0].stable),
            amounts[0]
        );
        _swap(amounts, routes, to);
    }

    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        route[] calldata routes,
        address to,
        uint deadline
    ) external ensure(deadline) returns (uint[] memory amounts) {
        amounts = getAmountsOut(amountIn, routes);
        require(
            amounts[amounts.length - 1] >= amountOutMin,
            "Router: INSUFFICIENT_OUTPUT_AMOUNT"
        );
        _safeTransfer(
            routes[0].from,
            msg.sender,
            pairFor(routes[0].from, routes[0].to, routes[0].stable),
            amounts[0]
        );
        _swap(amounts, routes, to);
    }

    function swapExactETHForTokens(
        uint amountOutMin,
        route[] calldata routes,
        address to,
        uint deadline
    ) external payable ensure(deadline) returns (uint[] memory amounts) {
        require(routes[0].from == address(weth), "Router: INVALID_PATH");
        amounts = getAmountsOut(msg.value, routes);
        require(
            amounts[amounts.length - 1] >= amountOutMin,
            "Router: INSUFFICIENT_OUTPUT_AMOUNT"
        );
        weth.deposit{value: amounts[0]}();
        assert(
            weth.transfer(
                pairFor(routes[0].from, routes[0].to, routes[0].stable),
                amounts[0]
            )
        );
        _swap(amounts, routes, to);
    }

    function swapExactTokensForETH(
        uint amountIn,
        uint amountOutMin,
        route[] calldata routes,
        address to,
        uint deadline
    ) external ensure(deadline) returns (uint[] memory amounts) {
        require(
            routes[routes.length - 1].to == address(weth),
            "Router: INVALID_PATH"
        );
        amounts = getAmountsOut(amountIn, routes);
        require(
            amounts[amounts.length - 1] >= amountOutMin,
            "Router: INSUFFICIENT_OUTPUT_AMOUNT"
        );
        _safeTransfer(
            routes[0].from,
            msg.sender,
            pairFor(routes[0].from, routes[0].to, routes[0].stable),
            amounts[0]
        );
        _swap(amounts, routes, address(this));
        weth.withdraw(amounts[amounts.length - 1]);
        _safeTransferETH(to, amounts[amounts.length - 1]);
    }

    function UNSAFE_swapExactTokensForTokens(
        uint[] memory amounts,
        route[] calldata routes,
        address to,
        uint deadline
    ) external ensure(deadline) returns (uint[] memory) {
        _safeTransfer(
            routes[0].from,
            msg.sender,
            pairFor(routes[0].from, routes[0].to, routes[0].stable),
            amounts[0]
        );
        _swap(amounts, routes, to);
        return amounts;
    }

    function _safeTransferETH(address to, uint value) internal {
        (bool success, ) = to.call{value: value}(new bytes(0));
        require(success, "TransferHelper: ETH_TRANSFER_FAILED");
    }

    function _safeTransfer(
        address token,
        address from,
        address to,
        uint256 value
    ) internal {
        if (token == address(0)) {
            require(msg.value >= value, "not enough value");
            (bool success, ) = payable(to).call{value: value}("");
            require(success, "Should transfer ethers");
        } else {
            if (from == address(this)) {
                IERC20(token).safeTransfer(to, value);
            } else {
                IERC20(token).safeTransferFrom(from, to, value);
            }
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.20;

import {IERC20} from "../IERC20.sol";
import {IERC20Permit} from "../extensions/IERC20Permit.sol";
import {Address} from "../../../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;

    /**
     * @dev An operation with an ERC20 token failed.
     */
    error SafeERC20FailedOperation(address token);

    /**
     * @dev Indicates a failed `decreaseAllowance` request.
     */
    error SafeERC20FailedDecreaseAllowance(address spender, uint256 currentAllowance, uint256 requestedDecrease);

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeCall(token.transfer, (to, value)));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeCall(token.transferFrom, (from, to, value)));
    }

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        forceApprove(token, spender, oldAllowance + value);
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `requestedDecrease`. If `token` returns no
     * value, non-reverting calls are assumed to be successful.
     */
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 requestedDecrease) internal {
        unchecked {
            uint256 currentAllowance = token.allowance(address(this), spender);
            if (currentAllowance < requestedDecrease) {
                revert SafeERC20FailedDecreaseAllowance(spender, currentAllowance, requestedDecrease);
            }
            forceApprove(token, spender, currentAllowance - requestedDecrease);
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
     * to be set to zero before setting it to a non-zero value, such as USDT.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeCall(token.approve, (spender, value));

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeCall(token.approve, (spender, 0)));
            _callOptionalReturn(token, approvalCall);
        }
    }

    /**
     * @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);
        if (returndata.length != 0 && !abi.decode(returndata, (bool))) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @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).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        // 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 cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.

        (bool success, bytes memory returndata) = address(token).call(data);
        return success && (returndata.length == 0 || abi.decode(returndata, (bool))) && address(token).code.length > 0;
    }
}

{
  "compilationTarget": {
    "contracts/Router.sol": "Router"
  },
  "evmVersion": "paris",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs",
    "useLiteralContent": true
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}