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

import "@openzeppelin/contracts/access/Ownable.sol";

import "@openzeppelin/contracts/security/ReentrancyGuard.sol";

import "./interfaces/IStableSwap.sol";
import "./interfaces/IStableSwapFactory.sol";
import "./interfaces/IArbswapV2Factory.sol";
import "./interfaces/IWETH02.sol";
import "./libraries/UniERC20.sol";
import "./libraries/SafeERC20.sol";
import "./libraries/ArbswapV2ExchangeLib.sol";

contract ArbswapSmartRouter is Ownable, ReentrancyGuard {
    using UniERC20 for IERC20;
    using SafeERC20 for IERC20;
    using ArbswapV2ExchangeLib for IArbswapV2Exchange;

    enum FLAG {
        STABLE_SWAP,
        V2_EXACT_IN
    }

    IWETH02 public immutable weth;
    address public immutable arbswapV2;
    address public stableswapFactory;

    event NewStableSwapFactory(address indexed sender, address indexed factory);
    event SwapMulti(
        address indexed sender,
        address indexed srcTokenAddr,
        address indexed dstTokenAddr,
        uint256 srcAmount
    );
    event Swap(
        address indexed sender,
        address indexed srcTokenAddr,
        address indexed dstTokenAddr,
        uint256 srcAmount
    );

    fallback() external {}

    receive() external payable {}

    /*
     * @notice Constructor
     * @param _WETHAddress: address of the WETH contract
     * @param _arbswapV2: address of the ArbswapFactory
     * @param _stableswapFactory: address of the StableSwapFactory
     */
    constructor(
        address _WETHAddress,
        address _arbswapV2,
        address _stableswapFactory
    ) {
        weth = IWETH02(_WETHAddress);
        arbswapV2 = _arbswapV2;
        stableswapFactory = _stableswapFactory;
    }

    /**
     * @notice Sets treasury address
     * @dev Only callable by the contract owner.
     */
    function setStableSwapFactory(address _factory) external onlyOwner {
        require(
            _factory != address(0),
            "StableSwap factory cannot be zero address"
        );
        stableswapFactory = _factory;
        emit NewStableSwapFactory(msg.sender, stableswapFactory);
    }

    function swapMulti(
        IERC20[] calldata tokens,
        uint256 amount,
        uint256 minReturn,
        FLAG[] calldata flags
    ) public payable nonReentrant returns (uint256 returnAmount) {
        require(tokens.length == flags.length + 1, "swapMulti: wrong length");

        IERC20 srcToken = tokens[0];
        IERC20 dstToken = tokens[tokens.length - 1];

        if (srcToken == dstToken) {
            return amount;
        }

        srcToken.uniTransferFrom(payable(msg.sender), address(this), amount);
        uint256 receivedAmount = srcToken.uniBalanceOf(address(this));

        for (uint256 i = 1; i < tokens.length; i++) {
            if (tokens[i - 1] == tokens[i]) {
                continue;
            }

            if (flags[i - 1] == FLAG.STABLE_SWAP) {
                _swapOnStableSwap(
                    tokens[i - 1],
                    tokens[i],
                    tokens[i - 1].uniBalanceOf(address(this))
                );
            } else if (flags[i - 1] == FLAG.V2_EXACT_IN) {
                _swapOnV2ExactIn(
                    tokens[i - 1],
                    tokens[i],
                    tokens[i - 1].uniBalanceOf(address(this))
                );
            }
        }

        returnAmount = dstToken.uniBalanceOf(address(this));
        require(
            returnAmount >= minReturn,
            "swapMulti: return amount is less than minReturn"
        );
        uint256 inRefund = srcToken.uniBalanceOf(address(this));
        emit SwapMulti(
            msg.sender,
            address(srcToken),
            address(dstToken),
            receivedAmount - inRefund
        );

        uint256 userBalanceBefore = dstToken.uniBalanceOf(msg.sender);
        dstToken.uniTransfer(payable(msg.sender), returnAmount);
        require(
            dstToken.uniBalanceOf(msg.sender) - userBalanceBefore >= minReturn,
            "swapMulti: incorrect user balance"
        );

        srcToken.uniTransfer(payable(msg.sender), inRefund);
    }

    function swap(
        IERC20 srcToken,
        IERC20 dstToken,
        uint256 amount,
        uint256 minReturn,
        FLAG flag
    ) public payable nonReentrant returns (uint256 returnAmount) {
        if (srcToken == dstToken) {
            return amount;
        }

        srcToken.uniTransferFrom(payable(msg.sender), address(this), amount);
        uint256 receivedAmount = srcToken.uniBalanceOf(address(this));

        if (flag == FLAG.STABLE_SWAP) {
            _swapOnStableSwap(srcToken, dstToken, receivedAmount);
        } else if (flag == FLAG.V2_EXACT_IN) {
            _swapOnV2ExactIn(srcToken, dstToken, receivedAmount);
        }

        returnAmount = dstToken.uniBalanceOf(address(this));
        require(
            returnAmount >= minReturn,
            "swap: return amount is less than minReturn"
        );
        uint256 inRefund = srcToken.uniBalanceOf(address(this));
        emit Swap(
            msg.sender,
            address(srcToken),
            address(dstToken),
            receivedAmount - inRefund
        );

        uint256 userBalanceBefore = dstToken.uniBalanceOf(msg.sender);
        dstToken.uniTransfer(payable(msg.sender), returnAmount);
        require(
            dstToken.uniBalanceOf(msg.sender) - userBalanceBefore >= minReturn,
            "swap: incorrect user balance"
        );

        srcToken.uniTransfer(payable(msg.sender), inRefund);
    }

    // Swap helpers

    function _swapOnStableSwap(
        IERC20 srcToken,
        IERC20 dstToken,
        uint256 amount
    ) internal {
        require(
            stableswapFactory != address(0),
            "StableSwap factory cannot be zero address"
        );

        if (srcToken.isETH()) {
            weth.deposit{value: amount}();
        }

        IERC20 srcTokenReal = srcToken.isETH() ? weth : srcToken;
        IERC20 dstTokenReal = dstToken.isETH() ? weth : dstToken;

        IStableSwapFactory.StableSwapPairInfo memory info = IStableSwapFactory(
            stableswapFactory
        ).getPairInfo(address(srcTokenReal), address(dstTokenReal));

        if (info.swapContract == address(0)) {
            return;
        }

        IStableSwap stableSwap = IStableSwap(info.swapContract);
        IERC20[] memory tokens = new IERC20[](2);
        tokens[0] = IERC20(stableSwap.coins(uint256(0)));
        tokens[1] = IERC20(stableSwap.coins(uint256(1)));
        uint256 i = (srcTokenReal == tokens[0] ? 1 : 0) +
            (srcTokenReal == tokens[1] ? 2 : 0);
        uint256 j = (dstTokenReal == tokens[0] ? 1 : 0) +
            (dstTokenReal == tokens[1] ? 2 : 0);
        srcTokenReal.uniApprove(address(stableSwap), amount);
        stableSwap.exchange(i - 1, j - 1, amount, 0);

        if (dstToken.isETH()) {
            weth.withdraw(weth.balanceOf(address(this)));
        }
    }

    function _swapOnV2ExactIn(
        IERC20 srcToken,
        IERC20 dstToken,
        uint256 amount
    ) internal returns (uint256 returnAmount) {
        if (srcToken.isETH()) {
            weth.deposit{value: amount}();
        }

        IERC20 srcTokenReal = srcToken.isETH() ? weth : srcToken;
        IERC20 dstTokenReal = dstToken.isETH() ? weth : dstToken;
        IArbswapV2Exchange exchange = IArbswapV2Factory(arbswapV2).getPair(
            srcTokenReal,
            dstTokenReal
        );

        srcTokenReal.safeTransfer(address(exchange), amount);
        bool needSync;
        (returnAmount, needSync) = exchange.getReturn(
            srcTokenReal,
            dstTokenReal,
            amount
        );
        if (needSync) {
            exchange.sync();
        }
        if (srcTokenReal < dstTokenReal) {
            exchange.swap(0, returnAmount, address(this), "");
        } else {
            exchange.swap(returnAmount, 0, address(this), "");
        }

        if (dstToken.isETH()) {
            weth.withdraw(weth.balanceOf(address(this)));
        }
    }
}

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

import "../interfaces/IArbswapV2Factory.sol";
import "../interfaces/IArbswapV2Exchange.sol";
import "./UniERC20.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/utils/math/Math.sol";

library ArbswapV2ExchangeLib {
    using Math for uint256;
    using UniERC20 for IERC20;

    function getReturn(
        IArbswapV2Exchange exchange,
        IERC20 srcToken,
        IERC20 dstToken,
        uint256 amountIn
    ) internal view returns (uint256 result, bool needSync) {
        uint256 reserveIn = srcToken.uniBalanceOf(address(exchange));
        uint256 reserveOut = dstToken.uniBalanceOf(address(exchange));
        (uint112 reserve0, uint112 reserve1, ) = exchange.getReserves();
        if (srcToken > dstToken) {
            (reserve0, reserve1) = (reserve1, reserve0);
        }
        amountIn = reserveIn - reserve0;
        needSync = (reserveIn < reserve0 || reserveOut < reserve1);

        uint256 amountInWithFee = amountIn * 997;
        uint256 numerator = amountInWithFee * Math.min(reserveOut, reserve1);
        uint256 denominator = Math.min(reserveIn, reserve0) *
            1000 +
            amountInWithFee;
        result = (denominator == 0) ? 0 : numerator / denominator;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

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

interface IArbswapV2Exchange {
    function getReserves()
        external
        view
        returns (
            uint112 _reserve0,
            uint112 _reserve1,
            uint32 _blockTimestampLast
        );

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

    function skim(address to) external;

    function sync() external;
}

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

import "./IArbswapV2Exchange.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

interface IArbswapV2Factory {
    function getPair(
        IERC20 tokenA,
        IERC20 tokenB
    ) external view returns (IArbswapV2Exchange pair);
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;
pragma abicoder v1;

interface IDaiLikePermit {
    function permit(
        address holder,
        address spender,
        uint256 nonce,
        uint256 expiry,
        bool allowed,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (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
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;
pragma abicoder v1;

interface IERC20MetadataUppercase {
    function NAME() external view returns (string memory); // solhint-disable-line func-name-mixedcase

    function SYMBOL() external view returns (string memory); // solhint-disable-line func-name-mixedcase
}

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

interface IStableSwap {
    // solium-disable-next-line mixedcase
    function get_dy(
        uint256 i,
        uint256 j,
        uint256 dx
    ) external view returns (uint256 dy);

    // solium-disable-next-line mixedcase
    function exchange(
        uint256 i,
        uint256 j,
        uint256 dx,
        uint256 minDy
    ) external payable;

    // solium-disable-next-line mixedcase
    function coins(uint256 i) external view returns (address);

    // solium-disable-next-line mixedcase
    function balances(uint256 i) external view returns (uint256);

    // solium-disable-next-line mixedcase
    function A() external view returns (uint256);

    // solium-disable-next-line mixedcase
    function fee() external view returns (uint256);
}

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

interface IStableSwapFactory {
    struct StableSwapPairInfo {
        address swapContract;
        address token0;
        address token1;
        address LPContract;
    }

    // solium-disable-next-line mixedcase
    function pairLength() external view returns (uint256);

    // solium-disable-next-line mixedcase
    function getPairInfo(
        address _tokenA,
        address _tokenB
    ) external view returns (StableSwapPairInfo memory info);
}

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

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

interface IWETH02 is IERC20 {
    function deposit() external payable;

    function withdraw(uint256 amount) external;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (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) {
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            require(denominator > prod1);

            ///////////////////////////////////////////////
            // 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 10, 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 * 8) < value ? 1 : 0);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be _NOT_ENTERED
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;
    }

    function _nonReentrantAfter() private {
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;
pragma abicoder v1;

/// @title Revert reason forwarder.
library RevertReasonForwarder {
    /// @dev Forwards latest externall call revert.
    function reRevert() internal pure {
        // bubble up revert reason from latest external call
        /// @solidity memory-safe-assembly
        assembly {
            // solhint-disable-line no-inline-assembly
            let ptr := mload(0x40)
            returndatacopy(ptr, 0, returndatasize())
            revert(ptr, returndatasize())
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;
pragma abicoder v1;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol";
import "../interfaces/IDaiLikePermit.sol";
import "./RevertReasonForwarder.sol";

/// @title Implements efficient safe methods for ERC20 interface.
library SafeERC20 {
    error SafeTransferFailed();
    error SafeTransferFromFailed();
    error ForceApproveFailed();
    error SafeIncreaseAllowanceFailed();
    error SafeDecreaseAllowanceFailed();
    error SafePermitBadLength();

    /// @dev Ensures method do not revert or return boolean `true`, admits call to non-smart-contract.
    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 amount
    ) internal {
        bytes4 selector = token.transferFrom.selector;
        bool success;
        /// @solidity memory-safe-assembly
        assembly {
            // solhint-disable-line no-inline-assembly
            let data := mload(0x40)

            mstore(data, selector)
            mstore(add(data, 0x04), from)
            mstore(add(data, 0x24), to)
            mstore(add(data, 0x44), amount)
            success := call(gas(), token, 0, data, 100, 0x0, 0x20)
            if success {
                switch returndatasize()
                case 0 {
                    success := gt(extcodesize(token), 0)
                }
                default {
                    success := and(gt(returndatasize(), 31), eq(mload(0), 1))
                }
            }
        }
        if (!success) revert SafeTransferFromFailed();
    }

    /// @dev Ensures method do not revert or return boolean `true`, admits call to non-smart-contract.
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        if (!_makeCall(token, token.transfer.selector, to, value)) {
            revert SafeTransferFailed();
        }
    }

    /// @dev If `approve(from, to, amount)` fails, try to `approve(from, to, 0)` before retry.
    function forceApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        if (!_makeCall(token, token.approve.selector, spender, value)) {
            if (
                !_makeCall(token, token.approve.selector, spender, 0) ||
                !_makeCall(token, token.approve.selector, spender, value)
            ) {
                revert ForceApproveFailed();
            }
        }
    }

    /// @dev Allowance increase with safe math check.
    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 allowance = token.allowance(address(this), spender);
        if (value > type(uint256).max - allowance)
            revert SafeIncreaseAllowanceFailed();
        forceApprove(token, spender, allowance + value);
    }

    /// @dev Allowance decrease with safe math check.
    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 allowance = token.allowance(address(this), spender);
        if (value > allowance) revert SafeDecreaseAllowanceFailed();
        forceApprove(token, spender, allowance - value);
    }

    /// @dev Calls either ERC20 or Dai `permit` for `token`, if unsuccessful forwards revert from external call.
    function safePermit(IERC20 token, bytes calldata permit) internal {
        if (!tryPermit(token, permit)) RevertReasonForwarder.reRevert();
    }

    function tryPermit(
        IERC20 token,
        bytes calldata permit
    ) internal returns (bool) {
        if (permit.length == 32 * 7) {
            return
                _makeCalldataCall(token, IERC20Permit.permit.selector, permit);
        }
        if (permit.length == 32 * 8) {
            return
                _makeCalldataCall(
                    token,
                    IDaiLikePermit.permit.selector,
                    permit
                );
        }
        revert SafePermitBadLength();
    }

    function _makeCall(
        IERC20 token,
        bytes4 selector,
        address to,
        uint256 amount
    ) private returns (bool success) {
        /// @solidity memory-safe-assembly
        assembly {
            // solhint-disable-line no-inline-assembly
            let data := mload(0x40)

            mstore(data, selector)
            mstore(add(data, 0x04), to)
            mstore(add(data, 0x24), amount)
            success := call(gas(), token, 0, data, 0x44, 0x0, 0x20)
            if success {
                switch returndatasize()
                case 0 {
                    success := gt(extcodesize(token), 0)
                }
                default {
                    success := and(gt(returndatasize(), 31), eq(mload(0), 1))
                }
            }
        }
    }

    function _makeCalldataCall(
        IERC20 token,
        bytes4 selector,
        bytes calldata args
    ) private returns (bool success) {
        /// @solidity memory-safe-assembly
        assembly {
            // solhint-disable-line no-inline-assembly
            let len := add(4, args.length)
            let data := mload(0x40)

            mstore(data, selector)
            calldatacopy(add(data, 0x04), args.offset, args.length)
            success := call(gas(), token, 0, data, len, 0x0, 0x20)
            if success {
                switch returndatasize()
                case 0 {
                    success := gt(extcodesize(token), 0)
                }
                default {
                    success := and(gt(returndatasize(), 31), eq(mload(0), 1))
                }
            }
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;
pragma abicoder v1;

/// @title Library with gas-efficient string operations
library StringUtil {
    function toHex(uint256 value) internal pure returns (string memory) {
        return toHex(abi.encodePacked(value));
    }

    function toHex(address value) internal pure returns (string memory) {
        return toHex(abi.encodePacked(value));
    }

    /// @dev this is the assembly adaptation of highly optimized toHex16 code from Mikhail Vladimirov
    /// https://stackoverflow.com/a/69266989
    function toHex(
        bytes memory data
    ) internal pure returns (string memory result) {
        /// @solidity memory-safe-assembly
        assembly {
            // solhint-disable-line no-inline-assembly
            function _toHex16(input) -> output {
                output := or(
                    and(
                        input,
                        0xFFFFFFFFFFFFFFFF000000000000000000000000000000000000000000000000
                    ),
                    shr(
                        64,
                        and(
                            input,
                            0x0000000000000000FFFFFFFFFFFFFFFF00000000000000000000000000000000
                        )
                    )
                )
                output := or(
                    and(
                        output,
                        0xFFFFFFFF000000000000000000000000FFFFFFFF000000000000000000000000
                    ),
                    shr(
                        32,
                        and(
                            output,
                            0x00000000FFFFFFFF000000000000000000000000FFFFFFFF0000000000000000
                        )
                    )
                )
                output := or(
                    and(
                        output,
                        0xFFFF000000000000FFFF000000000000FFFF000000000000FFFF000000000000
                    ),
                    shr(
                        16,
                        and(
                            output,
                            0x0000FFFF000000000000FFFF000000000000FFFF000000000000FFFF00000000
                        )
                    )
                )
                output := or(
                    and(
                        output,
                        0xFF000000FF000000FF000000FF000000FF000000FF000000FF000000FF000000
                    ),
                    shr(
                        8,
                        and(
                            output,
                            0x00FF000000FF000000FF000000FF000000FF000000FF000000FF000000FF0000
                        )
                    )
                )
                output := or(
                    shr(
                        4,
                        and(
                            output,
                            0xF000F000F000F000F000F000F000F000F000F000F000F000F000F000F000F000
                        )
                    ),
                    shr(
                        8,
                        and(
                            output,
                            0x0F000F000F000F000F000F000F000F000F000F000F000F000F000F000F000F00
                        )
                    )
                )
                output := add(
                    add(
                        0x3030303030303030303030303030303030303030303030303030303030303030,
                        output
                    ),
                    mul(
                        and(
                            shr(
                                4,
                                add(
                                    output,
                                    0x0606060606060606060606060606060606060606060606060606060606060606
                                )
                            ),
                            0x0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F0F
                        ),
                        7 // Change 7 to 39 for lower case output
                    )
                )
            }

            result := mload(0x40)
            let length := mload(data)
            let resultLength := shl(1, length)
            let toPtr := add(result, 0x22) // 32 bytes for length + 2 bytes for '0x'
            mstore(0x40, add(toPtr, resultLength)) // move free memory pointer
            mstore(add(result, 2), 0x3078) // 0x3078 is right aligned so we write to `result + 2`
            // to store the last 2 bytes in the beginning of the string
            mstore(result, add(resultLength, 2)) // extra 2 bytes for '0x'

            for {
                let fromPtr := add(data, 0x20)
                let endPtr := add(fromPtr, length)
            } lt(fromPtr, endPtr) {
                fromPtr := add(fromPtr, 0x20)
            } {
                let rawData := mload(fromPtr)
                let hexData := _toHex16(rawData)
                mstore(toPtr, hexData)
                toPtr := add(toPtr, 0x20)
                hexData := _toHex16(shl(128, rawData))
                mstore(toPtr, hexData)
                toPtr := add(toPtr, 0x20)
            }
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;
pragma abicoder v1;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import "../interfaces/IERC20MetadataUppercase.sol";
import "./SafeERC20.sol";
import "./StringUtil.sol";

/// @title Library, which allows usage of ETH as ERC20 and ERC20 itself. Uses SafeERC20 library for ERC20 interface.
library UniERC20 {
    using SafeERC20 for IERC20;

    error InsufficientBalance();
    error ApproveCalledOnETH();
    error NotEnoughValue();
    error FromIsNotSender();
    error ToIsNotThis();
    error ETHTransferFailed();

    uint256 private constant _RAW_CALL_GAS_LIMIT = 5000;
    IERC20 private constant _ETH_ADDRESS =
        IERC20(0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE);
    IERC20 private constant _ZERO_ADDRESS = IERC20(address(0));

    /// @dev Returns true if `token` is ETH.
    function isETH(IERC20 token) internal pure returns (bool) {
        return (token == _ZERO_ADDRESS || token == _ETH_ADDRESS);
    }

    /// @dev Returns `account` ERC20 `token` balance.
    function uniBalanceOf(
        IERC20 token,
        address account
    ) internal view returns (uint256) {
        if (isETH(token)) {
            return account.balance;
        } else {
            return token.balanceOf(account);
        }
    }

    /// @dev `token` transfer `to` `amount`.
    /// Note that this function does nothing in case of zero amount.
    function uniTransfer(
        IERC20 token,
        address payable to,
        uint256 amount
    ) internal {
        if (amount > 0) {
            if (isETH(token)) {
                if (address(this).balance < amount)
                    revert InsufficientBalance();
                // solhint-disable-next-line avoid-low-level-calls
                (bool success, ) = to.call{
                    value: amount,
                    gas: _RAW_CALL_GAS_LIMIT
                }("");
                if (!success) revert ETHTransferFailed();
            } else {
                token.safeTransfer(to, amount);
            }
        }
    }

    /// @dev `token` transfer `from` `to` `amount`.
    /// Note that this function does nothing in case of zero amount.
    function uniTransferFrom(
        IERC20 token,
        address payable from,
        address to,
        uint256 amount
    ) internal {
        if (amount > 0) {
            if (isETH(token)) {
                if (msg.value < amount) revert NotEnoughValue();
                if (from != msg.sender) revert FromIsNotSender();
                if (to != address(this)) revert ToIsNotThis();
                if (msg.value > amount) {
                    // Return remainder if exist
                    unchecked {
                        // solhint-disable-next-line avoid-low-level-calls
                        (bool success, ) = from.call{
                            value: msg.value - amount,
                            gas: _RAW_CALL_GAS_LIMIT
                        }("");
                        if (!success) revert ETHTransferFailed();
                    }
                }
            } else {
                token.safeTransferFrom(from, to, amount);
            }
        }
    }

    /// @dev Returns `token` symbol from ERC20 metadata.
    function uniSymbol(IERC20 token) internal view returns (string memory) {
        return
            _uniDecode(
                token,
                IERC20Metadata.symbol.selector,
                IERC20MetadataUppercase.SYMBOL.selector
            );
    }

    /// @dev Returns `token` name from ERC20 metadata.
    function uniName(IERC20 token) internal view returns (string memory) {
        return
            _uniDecode(
                token,
                IERC20Metadata.name.selector,
                IERC20MetadataUppercase.NAME.selector
            );
    }

    /// @dev Reverts if `token` is ETH, otherwise performs ERC20 forceApprove.
    function uniApprove(IERC20 token, address to, uint256 amount) internal {
        if (isETH(token)) revert ApproveCalledOnETH();

        token.forceApprove(to, amount);
    }

    /// @dev 20K gas is provided to account for possible implementations of name/symbol
    /// (token implementation might be behind proxy or store the value in storage)
    function _uniDecode(
        IERC20 token,
        bytes4 lowerCaseSelector,
        bytes4 upperCaseSelector
    ) private view returns (string memory result) {
        if (isETH(token)) {
            return "ETH";
        }

        (bool success, bytes memory data) = address(token).staticcall{
            gas: 20000
        }(abi.encodeWithSelector(lowerCaseSelector));
        if (!success) {
            (success, data) = address(token).staticcall{gas: 20000}(
                abi.encodeWithSelector(upperCaseSelector)
            );
        }

        if (success && data.length >= 0x40) {
            (uint256 offset, uint256 len) = abi.decode(
                data,
                (uint256, uint256)
            );
            /*
            return data is padded up to 32 bytes with ABI encoder also sometimes
            there is extra 32 bytes of zeros padded in the end:
            https://github.com/ethereum/solidity/issues/10170
            because of that we can't check for equality and instead check
            that overall data length is greater or equal than string length + extra 64 bytes
            */
            if (offset == 0x20 && data.length >= 0x40 + len) {
                /// @solidity memory-safe-assembly
                assembly {
                    // solhint-disable-line no-inline-assembly
                    result := add(data, 0x40)
                }
                return result;
            }
        }
        if (success && data.length == 32) {
            uint256 len = 0;
            while (
                len < data.length && data[len] >= 0x20 && data[len] <= 0x7E
            ) {
                unchecked {
                    len++;
                }
            }

            if (len > 0) {
                /// @solidity memory-safe-assembly
                assembly {
                    // solhint-disable-line no-inline-assembly
                    mstore(data, len)
                }
                return string(data);
            }
        }

        return StringUtil.toHex(address(token));
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @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.
 */
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].
     */
    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);
}

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