// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (proxy/Clones.sol)

pragma solidity ^0.8.0;

/**
 * @dev https://eips.ethereum.org/EIPS/eip-1167[EIP 1167] is a standard for
 * deploying minimal proxy contracts, also known as "clones".
 *
 * > To simply and cheaply clone contract functionality in an immutable way, this standard specifies
 * > a minimal bytecode implementation that delegates all calls to a known, fixed address.
 *
 * The library includes functions to deploy a proxy using either `create` (traditional deployment) or `create2`
 * (salted deterministic deployment). It also includes functions to predict the addresses of clones deployed using the
 * deterministic method.
 *
 * _Available since v3.4._
 */
library Clones {
    /**
     * @dev Deploys and returns the address of a clone that mimics the behaviour of `implementation`.
     *
     * This function uses the create opcode, which should never revert.
     */
    function clone(address implementation) internal returns (address instance) {
        /// @solidity memory-safe-assembly
        assembly {
            // Cleans the upper 96 bits of the `implementation` word, then packs the first 3 bytes
            // of the `implementation` address with the bytecode before the address.
            mstore(0x00, or(shr(0xe8, shl(0x60, implementation)), 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000))
            // Packs the remaining 17 bytes of `implementation` with the bytecode after the address.
            mstore(0x20, or(shl(0x78, implementation), 0x5af43d82803e903d91602b57fd5bf3))
            instance := create(0, 0x09, 0x37)
        }
        require(instance != address(0), "ERC1167: create failed");
    }

    /**
     * @dev Deploys and returns the address of a clone that mimics the behaviour of `implementation`.
     *
     * This function uses the create2 opcode and a `salt` to deterministically deploy
     * the clone. Using the same `implementation` and `salt` multiple time will revert, since
     * the clones cannot be deployed twice at the same address.
     */
    function cloneDeterministic(address implementation, bytes32 salt) internal returns (address instance) {
        /// @solidity memory-safe-assembly
        assembly {
            // Cleans the upper 96 bits of the `implementation` word, then packs the first 3 bytes
            // of the `implementation` address with the bytecode before the address.
            mstore(0x00, or(shr(0xe8, shl(0x60, implementation)), 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000))
            // Packs the remaining 17 bytes of `implementation` with the bytecode after the address.
            mstore(0x20, or(shl(0x78, implementation), 0x5af43d82803e903d91602b57fd5bf3))
            instance := create2(0, 0x09, 0x37, salt)
        }
        require(instance != address(0), "ERC1167: create2 failed");
    }

    /**
     * @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
     */
    function predictDeterministicAddress(
        address implementation,
        bytes32 salt,
        address deployer
    ) internal pure returns (address predicted) {
        /// @solidity memory-safe-assembly
        assembly {
            let ptr := mload(0x40)
            mstore(add(ptr, 0x38), deployer)
            mstore(add(ptr, 0x24), 0x5af43d82803e903d91602b57fd5bf3ff)
            mstore(add(ptr, 0x14), implementation)
            mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73)
            mstore(add(ptr, 0x58), salt)
            mstore(add(ptr, 0x78), keccak256(add(ptr, 0x0c), 0x37))
            predicted := keccak256(add(ptr, 0x43), 0x55)
        }
    }

    /**
     * @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
     */
    function predictDeterministicAddress(
        address implementation,
        bytes32 salt
    ) internal view returns (address predicted) {
        return predictDeterministicAddress(implementation, salt, address(this));
    }
}

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

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface IPair {
    function initialize(
        address _token0,
        address _token1,
        bool _stable
    ) external;

    function metadata()
        external
        view
        returns (
            uint256 dec0,
            uint256 dec1,
            uint256 r0,
            uint256 r1,
            bool st,
            address t0,
            address t1
        );

    function claimFees() external returns (uint256, uint256);

    function tokens() external view returns (address, address);

    function token0() external view returns (address);

    function token1() external view returns (address);

    function transferFrom(
        address src,
        address dst,
        uint256 amount
    ) external returns (bool);

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

    function swap(
        uint256 amount0Out,
        uint256 amount1Out,
        address to,
        bytes calldata data
    ) external;

    function burn(
        address to
    ) external returns (uint256 amount0, uint256 amount1);

    function mint(address to) external returns (uint256 liquidity);

    function getReserves()
        external
        view
        returns (
            uint256 _reserve0,
            uint256 _reserve1,
            uint256 _blockTimestampLast
        );

    function getAmountOut(uint256, address) external view returns (uint256);

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

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

    function totalSupply() external view returns (uint256);

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

    function decimals() external view returns (uint8);

    function claimable0(address _user) external view returns (uint256);

    function claimable1(address _user) external view returns (uint256);

    function stable() external view returns (bool);

    function skim(address to) external;
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface IPairFactory {
    function allPairsLength() external view returns (uint256);

    function isPair(address pair) external view returns (bool);

    function allPairs(uint256 index) external view returns (address);

    function getPair(
        address tokenA,
        address token,
        bool stable
    ) external view returns (address);

    function createPair(
        address tokenA,
        address tokenB,
        bool stable
    ) external returns (address pair);

    function getFeeAmount(
        bool _stable,
        uint256 _amount,
        address _account
    ) external view returns (uint256);

    function stableFee() external view returns (uint256);

    function volatileFee() external view returns (uint256);

    function isPrivileged(address _account) external view returns (bool);

    function isAMO(address _amo) external view returns (bool);
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

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

    function factory() external view returns (address);

    function addLiquidityETH(
        address token,
        bool stable,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (uint256 amountToken, uint256 amountETH, uint256 liquidity);
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

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 ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/utils/math/Math.sol";
import "@openzeppelin/contracts/proxy/Clones.sol";

import "./interfaces/IPair.sol";
import "./interfaces/IPairFactory.sol";
import "./interfaces/IRouter.sol";
import "./interfaces/IWETH.sol";

contract Router is IRouter {
    struct route {
        address from;
        address to;
        bool stable;
    }

    address public immutable factory;
    address public immutable pairLibrary;
    IWETH public immutable weth;
    uint256 internal constant MINIMUM_LIQUIDITY = 10 ** 3;

    // create swap event with sender and amountIn for the referral event reader system
    event Swap(address indexed sender, uint256 amount0In, address _tokenIn, address indexed to);

    modifier ensure(uint256 deadline) {
        require(deadline >= block.timestamp, "Router: EXPIRED");
        _;
    }

    constructor(address _factory, address _pairLibrary, address _weth) {
        factory = _factory;
        pairLibrary = _pairLibrary;
        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");
    }

    function pairFor(address tokenA, address tokenB, bool stable) public view returns (address pair) {
        pair = IPairFactory(factory).getPair(tokenA, tokenB, stable);
    }

    // given some amount of an asset and pair reserves, returns an equivalent amount of the other asset
    function quoteLiquidity(uint256 amountA, uint256 reserveA, uint256 reserveB) internal pure returns (uint256 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 (uint256 reserveA, uint256 reserveB) {
        (address token0, ) = sortTokens(tokenA, tokenB);
        (uint256 reserve0, uint256 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(uint256 amountIn, address tokenIn, address tokenOut) external view returns (uint256 amount, bool stable) {
        address pair = pairFor(tokenIn, tokenOut, true);
        uint256 amountStable;
        uint256 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(uint256 amountIn, route[] memory routes) public view returns (uint256[] memory amounts) {
        require(routes.length >= 1, "Router: INVALID_PATH");
        amounts = new uint256[](routes.length + 1);
        amounts[0] = amountIn;
        for (uint256 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,
        uint256 amountADesired,
        uint256 amountBDesired
    ) external view returns (uint256 amountA, uint256 amountB, uint256 liquidity) {
        // create the pair if it doesn't exist yet
        address _pair = IPairFactory(factory).getPair(tokenA, tokenB, stable);
        (uint256 reserveA, uint256 reserveB) = (0, 0);
        uint256 _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 {
            uint256 amountBOptimal = quoteLiquidity(amountADesired, reserveA, reserveB);
            if (amountBOptimal <= amountBDesired) {
                (amountA, amountB) = (amountADesired, amountBOptimal);
                liquidity = Math.min((amountA * _totalSupply) / reserveA, (amountB * _totalSupply) / reserveB);
            } else {
                uint256 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,
        uint256 liquidity
    ) external view returns (uint256 amountA, uint256 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);
        }

        (uint256 reserveA, uint256 reserveB) = getReserves(tokenA, tokenB, stable);
        uint256 _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,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin
    ) internal returns (uint256 amountA, uint256 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);
        }
        (uint256 reserveA, uint256 reserveB) = getReserves(tokenA, tokenB, stable);
        if (reserveA == 0 && reserveB == 0) {
            (amountA, amountB) = (amountADesired, amountBDesired);
        } else {
            uint256 amountBOptimal = quoteLiquidity(amountADesired, reserveA, reserveB);
            if (amountBOptimal <= amountBDesired) {
                require(amountBOptimal >= amountBMin, "Router: INSUFFICIENT_B_AMOUNT");
                (amountA, amountB) = (amountADesired, amountBOptimal);
            } else {
                uint256 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,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) external ensure(deadline) returns (uint256 amountA, uint256 amountB, uint256 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,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external payable ensure(deadline) returns (uint256 amountToken, uint256 amountETH, uint256 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,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) public ensure(deadline) returns (uint256 amountA, uint256 amountB) {
        address pair = pairFor(tokenA, tokenB, stable);
        require(IPair(pair).transferFrom(msg.sender, pair, liquidity)); // send liquidity to pair
        (uint256 amount0, uint256 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,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) public ensure(deadline) returns (uint256 amountToken, uint256 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,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountA, uint256 amountB) {
        address pair = pairFor(tokenA, tokenB, stable);
        {
            uint256 value = approveMax ? type(uint256).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,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountToken, uint256 amountETH) {
        address pair = pairFor(token, address(weth), stable);
        uint256 value = approveMax ? type(uint256).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(uint256[] memory amounts, route[] memory routes, address _to) internal virtual {
        for (uint256 i = 0; i < routes.length; i++) {
            (address token0, ) = sortTokens(routes[i].from, routes[i].to);
            uint256 amountOut = amounts[i + 1];
            (uint256 amount0Out, uint256 amount1Out) = routes[i].from == token0 ? (uint256(0), amountOut) : (amountOut, uint256(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));
        }
        emit Swap(msg.sender, amounts[0], routes[0].from, _to);
    }

    function swapExactTokensForTokensSimple(
        uint256 amountIn,
        uint256 amountOutMin,
        address tokenFrom,
        address tokenTo,
        bool stable,
        address to,
        uint256 deadline
    ) external ensure(deadline) returns (uint256[] 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(
        uint256 amountIn,
        uint256 amountOutMin,
        route[] calldata routes,
        address to,
        uint256 deadline
    ) external ensure(deadline) returns (uint256[] 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(
        uint256 amountOutMin,
        route[] calldata routes,
        address to,
        uint256 deadline
    ) external payable ensure(deadline) returns (uint256[] 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(
        uint256 amountIn,
        uint256 amountOutMin,
        route[] calldata routes,
        address to,
        uint256 deadline
    ) external ensure(deadline) returns (uint256[] 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 _safeTransferETH(address to, uint256 value) internal {
        if (value != 0) {
            (bool success, ) = to.call{value: value}(new bytes(0));
            require(success, "TransferHelper: ETH_TRANSFER_FAILED");
        }
    }

    function _safeTransfer(address token, address to, uint256 value) internal {
        if (value != 0) {
            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 {
        if (value != 0) {
            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": "paris",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 1000
  },
  "remappings": [],
  "viaIR": true
}