refactor mixSwap && add trade adapter

contracts/SmartRoute/adapter/UniAdapter.sol

@@ -0,0 +1,49 @@
+/*
+
+    Copyright 2020 DODO ZOO.
+    SPDX-License-Identifier: Apache-2.0
+
+*/
+
+pragma solidity 0.6.9;
+
+import {IDODOAdapter} from "../intf/IDODOAdapter.sol";
+import {IUni} from "../intf/IUni.sol";
+import {IERC20} from "../../intf/IERC20.sol";
+import {SafeMath} from "../../lib/SafeMath.sol";
+
+contract UniAdapter is IDODOAdapter {
+    using SafeMath for uint;
+
+    //fromToken == token0
+    function sellBase(address to, address pool) external override {
+        address baseToken = IUni(pool).token0();
+        (uint reserveIn, uint reserveOut,) = IUni(pool).getReserves();
+        require(reserveIn > 0 && reserveOut > 0, 'UniAdapter: INSUFFICIENT_LIQUIDITY');
+
+        uint balance0 = IERC20(baseToken).balanceOf(pool);
+        uint sellBaseAmount = balance0 - reserveIn;
+        
+        uint sellBaseAmountWithFee = sellBaseAmount.mul(997);
+        uint numerator = sellBaseAmountWithFee.mul(reserveOut);
+        uint denominator = reserveIn.mul(1000).add(sellBaseAmountWithFee);
+        uint receiveQuoteAmount = numerator / denominator;
+        IUni(pool).swap(0, receiveQuoteAmount, to, new bytes(0));
+    }
+
+    //fromToken == token1
+    function sellQuote(address to, address pool) external override {
+        address quoteToken = IUni(pool).token1();
+        (uint reserveOut, uint reserveIn,) = IUni(pool).getReserves();
+        require(reserveIn > 0 && reserveOut > 0, 'UniAdapter: INSUFFICIENT_LIQUIDITY');
+
+        uint balance1 = IERC20(quoteToken).balanceOf(pool);
+        uint sellQuoteAmount = balance1 - reserveIn;
+
+        uint sellQuoteAmountWithFee = sellQuoteAmount.mul(997);
+        uint numerator = sellQuoteAmountWithFee.mul(reserveOut);
+        uint denominator = reserveIn.mul(1000).add(sellQuoteAmountWithFee);
+        uint receiveBaseAmount = numerator / denominator;
+        IUni(pool).swap(receiveBaseAmount, 0, to, new bytes(0));
+    }
+}