/**
 *Submitted for verification at Etherscan.io on 2021-04-02
*/

// File: openzeppelin-solidity/contracts/token/ERC20/IERC20.sol



pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, 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 `sender` to `recipient` 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 sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @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);
}

// File: original_contracts/lib/chai/IChai.sol

pragma solidity 0.7.5;


interface IChai {

    function join(address dst, uint wad) external;

    function exit(address src, uint wad) external;
}

// File: openzeppelin-solidity/contracts/math/SafeMath.sol



pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: original_contracts/lib/SafeERC20.sol

pragma solidity 0.7.5;




library Address {

    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}


library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: original_contracts/ITokenTransferProxy.sol

pragma solidity 0.7.5;


interface ITokenTransferProxy {

    function transferFrom(
        address token,
        address from,
        address to,
        uint256 amount
    )
        external;

    function freeReduxTokens(address user, uint256 tokensToFree) external;
}

// File: original_contracts/lib/Utils.sol

pragma solidity 0.7.5;






library Utils {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    address constant ETH_ADDRESS = address(
        0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE
    );

    address constant WETH_ADDRESS = address(
        0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2
    );

    uint256 constant MAX_UINT = 2 ** 256 - 1;

    /**
   * @param fromToken Address of the source token
   * @param toToken Address of the destination token
   * @param fromAmount Amount of source tokens to be swapped
   * @param toAmount Minimum destination token amount expected out of this swap
   * @param expectedAmount Expected amount of destination tokens without slippage
   * @param beneficiary Beneficiary address
   * 0 then 100% will be transferred to beneficiary. Pass 10000 for 100%
   * @param referrer referral id
   * @param path Route to be taken for this swap to take place

   */
    struct SellData {
        address fromToken;
        uint256 fromAmount;
        uint256 toAmount;
        uint256 expectedAmount;
        address payable beneficiary;
        string referrer;
        bool useReduxToken;
        Utils.Path[] path;

    }

    struct MegaSwapSellData {
        address fromToken;
        uint256 fromAmount;
        uint256 toAmount;
        uint256 expectedAmount;
        address payable beneficiary;
        string referrer;
        bool useReduxToken;
        Utils.MegaSwapPath[] path;
    }

    struct BuyData {
        address fromToken;
        address toToken;
        uint256 fromAmount;
        uint256 toAmount;
        address payable beneficiary;
        string referrer;
        bool useReduxToken;
        Utils.BuyRoute[] route;
    }

    struct Route {
        address payable exchange;
        address targetExchange;
        uint percent;
        bytes payload;
        uint256 networkFee;//Network fee is associated with 0xv3 trades
    }

    struct MegaSwapPath {
        uint256 fromAmountPercent;
        Path[] path;
    }

    struct Path {
        address to;
        uint256 totalNetworkFee;//Network fee is associated with 0xv3 trades
        Route[] routes;
    }

    struct BuyRoute {
        address payable exchange;
        address targetExchange;
        uint256 fromAmount;
        uint256 toAmount;
        bytes payload;
        uint256 networkFee;//Network fee is associated with 0xv3 trades
    }

    function ethAddress() internal pure returns (address) {return ETH_ADDRESS;}

    function wethAddress() internal pure returns (address) {return WETH_ADDRESS;}

    function maxUint() internal pure returns (uint256) {return MAX_UINT;}

    function approve(
        address addressToApprove,
        address token,
        uint256 amount
    ) internal {
        if (token != ETH_ADDRESS) {
            IERC20 _token = IERC20(token);

            uint allowance = _token.allowance(address(this), addressToApprove);

            if (allowance < amount) {
                _token.safeApprove(addressToApprove, 0);
                _token.safeIncreaseAllowance(addressToApprove, MAX_UINT);
            }
        }
    }

    function transferTokens(
        address token,
        address payable destination,
        uint256 amount
    )
    internal
    {
        if (amount > 0) {
            if (token == ETH_ADDRESS) {
                (bool result, ) = destination.call{value: amount, gas: 4000}("");
                require(result, "Failed to transfer Ether");
            }
            else {
                IERC20(token).safeTransfer(destination, amount);
            }
        }

    }

    function tokenBalance(
        address token,
        address account
    )
    internal
    view
    returns (uint256)
    {
        if (token == ETH_ADDRESS) {
            return account.balance;
        } else {
            return IERC20(token).balanceOf(account);
        }
    }

    /**
    * @dev Helper method to refund gas using gas tokens
    */
    function refundGas(
        address account,
        address tokenTransferProxy,
        uint256 initialGas
    )
        internal
    {
        uint256 freeBase = 14154;
        uint256 freeToken = 6870;
        uint256 reimburse = 24000;

        uint256 tokens = initialGas.sub(
            gasleft()).add(freeBase).div(reimburse.mul(2).sub(freeToken)
        );

        freeGasTokens(account, tokenTransferProxy, tokens);
    }

    /**
    * @dev Helper method to free gas tokens
    */
    function freeGasTokens(address account, address tokenTransferProxy, uint256 tokens) internal {

        uint256 tokensToFree = tokens;
        uint256 safeNumTokens = 0;
        uint256 gas = gasleft();

        if (gas >= 27710) {
            safeNumTokens = gas.sub(27710).div(1148 + 5722 + 150);
        }

        if (tokensToFree > safeNumTokens) {
            tokensToFree = safeNumTokens;
        }
        ITokenTransferProxy(tokenTransferProxy).freeReduxTokens(account, tokensToFree);
    }
}

// File: original_contracts/lib/IExchange.sol

pragma solidity 0.7.5;



/**
* @dev This interface should be implemented by all exchanges which needs to integrate with the paraswap protocol
*/
interface IExchange {

    /**
   * @dev The function which performs the swap on an exchange.
   * Exchange needs to implement this method in order to support swapping of tokens through it
   * @param fromToken Address of the source token
   * @param toToken Address of the destination token
   * @param fromAmount Amount of source tokens to be swapped
   * @param toAmount Minimum destination token amount expected out of this swap
   * @param exchange Internal exchange or factory contract address for the exchange. For example Registry address for the Uniswap
   * @param payload Any exchange specific data which is required can be passed in this argument in encoded format which
   * will be decoded by the exchange. Each exchange will publish it's own decoding/encoding mechanism
   */
   //TODO: REMOVE RETURN STATEMENT
    function swap(
        IERC20 fromToken,
        IERC20 toToken,
        uint256 fromAmount,
        uint256 toAmount,
        address exchange,
        bytes calldata payload) external payable;

  /**
   * @dev The function which performs the swap on an exchange.
   * Exchange needs to implement this method in order to support swapping of tokens through it
   * @param fromToken Address of the source token
   * @param toToken Address of the destination token
   * @param fromAmount Max Amount of source tokens to be swapped
   * @param toAmount Destination token amount expected out of this swap
   * @param exchange Internal exchange or factory contract address for the exchange. For example Registry address for the Uniswap
   * @param payload Any exchange specific data which is required can be passed in this argument in encoded format which
   * will be decoded by the exchange. Each exchange will publish it's own decoding/encoding mechanism
   */
    function buy(
        IERC20 fromToken,
        IERC20 toToken,
        uint256 fromAmount,
        uint256 toAmount,
        address exchange,
        bytes calldata payload) external payable;

    /**
   * @dev This function is used to perform onChainSwap. It build all the parameters onchain. Basically the information
   * encoded in payload param of swap will calculated in this case
   * Exchange needs to implement this method in order to support swapping of tokens through it
   * @param fromToken Address of the source token
   * @param toToken Address of the destination token
   * @param fromAmount Amount of source tokens to be swapped
   * @param toAmount Minimum destination token amount expected out of this swap
   */
    function onChainSwap(
        IERC20 fromToken,
        IERC20 toToken,
        uint256 fromAmount,
        uint256 toAmount
    ) external payable returns (uint256);

    /**
    * @dev Certain adapters/exchanges needs to be initialized.
    * This method will be called from Augustus
    */
    function initialize(bytes calldata data) external;

    /**
    * @dev Returns unique identifier for the adapter
    */
    function getKey() external pure returns(bytes32);
}

// File: original_contracts/lib/chai/ChaiExchange.sol

pragma solidity 0.7.5;







contract ChaiExchange is IExchange {

    address public constant CHAI = address(0x06AF07097C9Eeb7fD685c692751D5C66dB49c215);
    address public constant DAI = address(0x6B175474E89094C44Da98b954EedeAC495271d0F);


    function initialize(bytes calldata data) external override {
        revert("METHOD NOT IMPLEMENTED");
    }

    function swap(
        IERC20 fromToken,
        IERC20 toToken,
        uint256 fromAmount,
        uint256 toAmount,
        address exchange,
        bytes calldata payload
    )
        external
        payable
        override

    {

        _swap(
            fromToken,
            toToken,
            fromAmount,
            toAmount,
            exchange,
            payload
        );
    }

    function buy(
        IERC20 fromToken,
        IERC20 toToken,
        uint256 fromAmount,
        uint256 toAmount,
        address exchange,
        bytes calldata payload
    )
        external
        payable
        override

    {

        _swap(
            fromToken,
            toToken,
            fromAmount,
            toAmount,
            exchange,
            payload
        );
    }

    function onChainSwap(
        IERC20 fromToken,
        IERC20 toToken,
        uint256 fromAmount,
        uint256 toAmount
    )
        external
        override
        payable
        returns (uint256)
    {
        revert("METHOD NOT SUPPORTED");
    }

    function getKey() public override pure returns(bytes32) {
        return keccak256(abi.encodePacked("CHAI", "1.0.0"));
    }

    function _swap(
        IERC20 fromToken,
        IERC20 toToken,
        uint256 fromAmount,
        uint256 toAmount,
        address exchange,
        bytes memory payload
    )
        private
    {

        Utils.approve(address(CHAI), address(fromToken), fromAmount);

        if (address(fromToken) == CHAI){
            require(address(toToken) == DAI, "Destination token should be DAI");
            IChai(CHAI).exit(address(this), fromAmount);
        }
        else if (address(fromToken) == DAI) {
            require(address(toToken) == CHAI, "Destination token should be CHAI");
            IChai(CHAI).join(address(this), fromAmount);
        }
        else {
            revert("Invalid fromToken");
        }
    }
}