Merge branch 'feature/V2' of github.com:DODOEX/contractV2 into feature/V2

contracts/SmartRoute/helper/DODOSwapCalcHelper.sol

@@ -0,0 +1,40 @@
+/*
+
+    Copyright 2020 DODO ZOO.
+    SPDX-License-Identifier: Apache-2.0
+
+*/
+
+pragma solidity 0.6.9;
+
+import {IDODOV1} from "../intf/IDODOV1.sol";
+import {IDODOSellHelper} from "./DODOSellHelper.sol";
+
+contract DODOSwapCalcHelper {
+    address public immutable _DODO_SELL_HELPER_;
+
+    constructor(address dodoSellHelper) public {
+        _DODO_SELL_HELPER_ = dodoSellHelper;
+    }
+
+    function calcReturnAmountV1(
+        uint256 fromTokenAmount,
+        address[] memory dodoPairs,
+        uint8[] memory directions
+    ) external view returns (uint256 returnAmount,uint256[] memory midPrices) {
+        returnAmount = fromTokenAmount;
+        midPrices = new uint256[](dodoPairs.length);
+        for (uint256 i = 0; i < dodoPairs.length; i++) {
+            address curDodoPair = dodoPairs[i];
+            if (directions[i] == 0) {
+                returnAmount = IDODOV1(curDodoPair).querySellBaseToken(returnAmount);
+            } else {
+                returnAmount = IDODOSellHelper(_DODO_SELL_HELPER_).querySellQuoteToken(
+                    curDodoPair,
+                    returnAmount
+                );
+            }
+            midPrices[i] = IDODOV1(curDodoPair).getMidPrice();
+        }        
+    }
+}

contracts/SmartRoute/intf/IDODOV1.sol

@@ -77,4 +77,6 @@ interface IDODOV1 {
     function getExpectedTarget() external view returns (uint256 baseTarget, uint256 quoteTarget);
 
     function getOraclePrice() external view returns (uint256);
+
+    function getMidPrice() external view returns (uint256 midPrice); 
 }