restruct contract repo

contracts/DODOVenderMachine/impl/DVMTrader.sol

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+/*
+
+    Copyright 2020 DODO ZOO.
+    SPDX-License-Identifier: Apache-2.0
+
+*/
+
+pragma solidity 0.6.9;
+pragma experimental ABIEncoderV2;
+
+import {DVMStorage} from "./DVMStorage.sol";
+import {SafeMath} from "../../lib/SafeMath.sol";
+import {DecimalMath} from "../../lib/DecimalMath.sol";
+import {DODOMath} from "../../lib/DODOMath.sol";
+ 
+contract DVMTrader is DVMStorage {
+  using SafeMath for uint256;
+
+  function sellBase (address to) external returns(uint256 receiveQuoteAmount){
+    uint256 baseInput = _VAULT_.getBaseInput();
+    uint256 mtFee;
+    (receiveQuoteAmount, mtFee) = querySellBase(baseInput);
+    _VAULT_.transferQuoteOut(to, receiveQuoteAmount);
+    if (mtFee>0){
+      _VAULT_.transferQuoteOut(_MAINTAINER_, mtFee);
+    }
+    _VAULT_.sync();
+    _updateBase0(); // 这里需要想想，原则上不需要update B0. 但精度问题，或者用户往合约里充值，可能导致需要updateBase0
+    return receiveQuoteAmount;
+  }
+
+  function sellQuote(address to) external returns(uint256 receiveBaseAmount){
+    uint256 quoteInput = _VAULT_.getQuoteInput();
+    uint256 mtFee;
+    (receiveBaseAmount, mtFee) = querySellQuote(quoteInput);
+    _VAULT_.transferBaseOut(to, receiveBaseAmount);
+    if (mtFee>0){
+      _VAULT_.transferBaseOut(_MAINTAINER_, mtFee);
+    }
+    _VAULT_.sync();
+    _updateBase0();
+    return receiveBaseAmount;
+  }
+
+  function querySellBase(uint256 payBaseAmount) public view returns(uint256 receiveQuoteAmount, uint256 mtFee){
+    uint256 B2 = _VAULT_._BASE_RESERVE_();
+    uint256 B1 = B2.add(payBaseAmount);
+    require(_BASE0_>=B1, "DODO_BASE_BALANCE_NOT_ENOUGH");
+    uint256 Q = DODOMath._GeneralIntegrate(_BASE0_, B1, B2, _I_, _K_);
+    uint256 lpFeeRate = _LP_FEE_RATE_MODEL_.getFeeRate(Q);
+    uint256 mtFeeRate = _MT_FEE_RATE_MODEL_.getFeeRate(Q);
+    mtFee = DecimalMath.mulCeil(Q, mtFeeRate);
+    receiveQuoteAmount = Q.sub(mtFee).sub(DecimalMath.mulCeil(Q, lpFeeRate));
+    return (receiveQuoteAmount, mtFee);
+  }
+
+  function querySellQuote(uint256 payQuoteAmount) public view returns(uint256 receiveBaseAmount, uint256 mtFee){
+    uint256 B1 = _VAULT_._BASE_RESERVE_();
+    uint256 fairAmount = DecimalMath.divFloor(payQuoteAmount, _I_);
+    uint256 newBaseReserve = DODOMath._SolveQuadraticFunctionForTrade(_BASE0_,B1,fairAmount,false, _K_);
+    uint256 deltaBase = B1.sub(newBaseReserve);
+    uint256 lpFeeRate = _LP_FEE_RATE_MODEL_.getFeeRate(payQuoteAmount);
+    uint256 mtFeeRate = _MT_FEE_RATE_MODEL_.getFeeRate(payQuoteAmount);
+    mtFee = DecimalMath.mulCeil(deltaBase, mtFeeRate);
+    receiveBaseAmount = deltaBase.sub(mtFee).sub(DecimalMath.mulCeil(deltaBase, lpFeeRate));
+    return (receiveBaseAmount, mtFee);
+  }
+
+}