pragma solidity 0.8.13;

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function transfer(address recipient, uint amount) external returns (bool);
    function decimals() external view returns (uint8);
    function symbol() external view returns (string memory);
    function balanceOf(address) external view returns (uint);
    function transferFrom(address sender, address recipient, uint amount) external returns (bool);
    function allowance(address owner, address spender) external view returns (uint);
    function approve(address spender, uint value) external returns (bool);

    event Transfer(address indexed from, address indexed to, uint value);
    event Approval(address indexed owner, address indexed spender, uint value);
}

pragma solidity 0.8.13;

interface IPair {
    function metadata() external view returns (uint dec0, uint dec1, uint r0, uint r1, bool st, address t0, address t1);
    function tokens() external returns (address, address);
    function token0() external returns (address);
    function token1() external returns (address);
    function externalBribe() external returns (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);
    function setHasGauge(bool value) external;
    function setExternalBribe(address _externalBribe) external;
    function hasGauge() external view returns (bool);
    function stable() external view returns (bool);
    function prices(address tokenIn, uint amountIn, uint points) external view returns (uint[] memory);
}

pragma solidity 0.8.13;

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

pragma solidity 0.8.13;

interface IRouter {
    function pairFor(address tokenA, address tokenB, bool stable) external view returns (address pair);
    function swapExactTokensForTokensSimple(uint amountIn, uint amountOutMin, address tokenFrom, address tokenTo, bool stable, address to, uint deadline) external returns (uint[] memory amounts);
    function getAmountOut(uint amountIn, address tokenIn, address tokenOut, bool stable) external view returns (uint amount);
	function getReserves(address tokenA, address tokenB, bool stable) external view returns (uint, uint);
    function addLiquidity(
        address tokenA,
        address tokenB,
        bool stable,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint, uint, uint);
}

pragma solidity 0.8.13;

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

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/math/Math.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
     * with further edits by Uniswap Labs also under MIT license.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                // The surrounding unchecked block does not change this fact.
                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            require(denominator > prod1, "Math: mulDiv overflow");

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
            // See https://cs.stackexchange.com/q/138556/92363.

            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
            // in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10 ** 64) {
                value /= 10 ** 64;
                result += 64;
            }
            if (value >= 10 ** 32) {
                value /= 10 ** 32;
                result += 32;
            }
            if (value >= 10 ** 16) {
                value /= 10 ** 16;
                result += 16;
            }
            if (value >= 10 ** 8) {
                value /= 10 ** 8;
                result += 8;
            }
            if (value >= 10 ** 4) {
                value /= 10 ** 4;
                result += 4;
            }
            if (value >= 10 ** 2) {
                value /= 10 ** 2;
                result += 2;
            }
            if (value >= 10 ** 1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity 0.8.13;

import 'openzeppelin-contracts/contracts/utils/math/Math.sol';
import 'contracts/interfaces/IERC20.sol';
import 'contracts/interfaces/IPair.sol';
import 'contracts/interfaces/IPairFactory.sol';
import 'contracts/interfaces/IRouter.sol';
import 'contracts/interfaces/IWETH.sol';

contract Router is IRouter {

    struct route {
        address from;
        address to;
        bool stable;
    }

    address public immutable factory;
    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, address _weth) {
        factory = _factory;
        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) public 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);
    }

    //@override
    //getAmountOut	:	bool stable
    //Gets exact output for specific pair-type(S|V)
    function getAmountOut(uint amountIn, address tokenIn, address tokenOut, bool stable) public view returns (uint amount) {
        address pair = pairFor(tokenIn, tokenOut, stable);
        if (IPairFactory(factory).isPair(pair)) {
            amount = IPair(pair).getAmountOut(amountIn, tokenIn);
        }
    }

    // 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,
        bool stable,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin
    ) 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)) {
            _pair = IPairFactory(factory).createPair(tokenA, tokenB, stable);
        }
        (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);
            }
        }
    }

    function addLiquidity(
        address tokenA,
        address tokenB,
        bool stable,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external ensure(deadline) returns (uint amountA, uint amountB, uint liquidity) {
        (amountA, amountB) = _addLiquidity(tokenA, tokenB, stable, amountADesired, amountBDesired, amountAMin, amountBMin);
        address pair = pairFor(tokenA, tokenB, stable);
        _safeTransferFrom(tokenA, msg.sender, pair, amountA);
        _safeTransferFrom(tokenB, msg.sender, pair, amountB);
        liquidity = IPair(pair).mint(to);
    }

    function addLiquidityETH(
        address token,
        bool stable,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable ensure(deadline) returns (uint amountToken, uint amountETH, uint liquidity) {
        (amountToken, amountETH) = _addLiquidity(
            token,
            address(weth),
            stable,
            amountTokenDesired,
            msg.value,
            amountTokenMin,
            amountETHMin
        );
        address pair = pairFor(token, address(weth), stable);
        _safeTransferFrom(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, 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');
        _safeTransferFrom(
            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');
        _safeTransferFrom(
            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');
        _safeTransferFrom(
            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) {
        _safeTransferFrom(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 to, uint256 value) internal {
        require(token.code.length > 0);
        (bool success, bytes memory data) =
        token.call(abi.encodeWithSelector(IERC20.transfer.selector, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))));
    }

    function _safeTransferFrom(address token, address from, address to, uint256 value) internal {
        require(token.code.length > 0);
        (bool success, bytes memory data) =
        token.call(abi.encodeWithSelector(IERC20.transferFrom.selector, from, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))));
    }
}

{
  "compilationTarget": {
    "contracts/Router.sol": "Router"
  },
  "evmVersion": "london",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": [
    ":ds-test/=lib/ds-test/src/",
    ":erc4626-tests/=lib/openzeppelin-contracts/lib/erc4626-tests/",
    ":forge-std/=lib/forge-std/src/",
    ":openzeppelin-contracts/=lib/openzeppelin-contracts/",
    ":openzeppelin/=lib/openzeppelin-contracts/contracts/",
    ":solmate/=lib/solmate/src/",
    ":utils/=test/utils/"
  ]
}