From 50e5ea907b9d3977b399ef78ef6ef06011ff1ca2 Mon Sep 17 00:00:00 2001
From: Gerardo Nardelli <gerardo.nardelli@altoros.com>
Date: Tue, 24 Nov 2020 12:11:13 -0300
Subject: [PATCH] Add first draft of swapAndRepay without using flash loans

---
 contracts/adapters/BaseUniswapAdapter.sol  | 29 ++++++++++++------
 contracts/adapters/UniswapRepayAdapter.sol | 34 ++++++++++++++++++++++
 2 files changed, 54 insertions(+), 9 deletions(-)

diff --git a/contracts/adapters/BaseUniswapAdapter.sol b/contracts/adapters/BaseUniswapAdapter.sol
index 7a727b7d..0e4ca193 100644
--- a/contracts/adapters/BaseUniswapAdapter.sol
+++ b/contracts/adapters/BaseUniswapAdapter.sol
@@ -73,7 +73,7 @@ contract BaseUniswapAdapter {
     view
     returns (uint256, uint256, uint256, uint256)
   {
-    AmountCalc memory results = _getAmountsOut(reserveIn, reserveOut, amountIn);
+    AmountCalc memory results = _getAmountsOutData(reserveIn, reserveOut, amountIn);
 
     return (
       results.calculatedAmount,
@@ -98,7 +98,7 @@ contract BaseUniswapAdapter {
     view
     returns (uint256, uint256, uint256, uint256)
   {
-    AmountCalc memory results = _getAmountsIn(reserveIn, reserveOut, amountOut);
+    AmountCalc memory results = _getAmountsInData(reserveIn, reserveOut, amountOut);
 
     return (
       results.calculatedAmount,
@@ -291,7 +291,7 @@ contract BaseUniswapAdapter {
    *   uint256 In amount of reserveIn value denominated in USD (8 decimals)
    *   uint256 Out amount of reserveOut value denominated in USD (8 decimals)
    */
-  function _getAmountsOut(address reserveIn, address reserveOut, uint256 amountIn) internal view returns (AmountCalc memory) {
+  function _getAmountsOutData(address reserveIn, address reserveOut, uint256 amountIn) internal view returns (AmountCalc memory) {
     // Subtract flash loan fee
     uint256 finalAmountIn = amountIn.sub(amountIn.mul(FLASHLOAN_PREMIUM_TOTAL).div(10000));
 
@@ -328,12 +328,8 @@ contract BaseUniswapAdapter {
    *   uint256 In amount of reserveIn value denominated in USD (8 decimals)
    *   uint256 Out amount of reserveOut value denominated in USD (8 decimals)
    */
-  function _getAmountsIn(address reserveIn, address reserveOut, uint256 amountOut) internal view returns (AmountCalc memory) {
-    address[] memory path = new address[](2);
-    path[0] = reserveIn;
-    path[1] = reserveOut;
-
-    uint256[] memory amounts = UNISWAP_ROUTER.getAmountsIn(amountOut, path);
+  function _getAmountsInData(address reserveIn, address reserveOut, uint256 amountOut) internal view returns (AmountCalc memory) {
+    uint256[] memory amounts = _getAmountsIn(reserveIn, reserveOut, amountOut);
 
     // Add flash loan fee
     uint256 finalAmountIn = amounts[0].add(amounts[0].mul(FLASHLOAN_PREMIUM_TOTAL).div(10000));
@@ -353,4 +349,19 @@ contract BaseUniswapAdapter {
       _calcUsdValue(reserveOut, amountOut, reserveOutDecimals)
     );
   }
+
+  /**
+ * @dev Calculates the input asset amount required to buy the given output asset amount
+ * @param reserveIn Address of the asset to be swap from
+ * @param reserveOut Address of the asset to be swap to
+ * @param amountOut Amount of reserveOut
+ * @return uint256[] amounts Array containing the amountIn and amountOut for a swap
+ */
+  function _getAmountsIn(address reserveIn, address reserveOut, uint256 amountOut) internal view returns (uint256[] memory) {
+    address[] memory path = new address[](2);
+    path[0] = reserveIn;
+    path[1] = reserveOut;
+
+    return UNISWAP_ROUTER.getAmountsIn(amountOut, path);
+  }
 }
diff --git a/contracts/adapters/UniswapRepayAdapter.sol b/contracts/adapters/UniswapRepayAdapter.sol
index c42df484..9c741745 100644
--- a/contracts/adapters/UniswapRepayAdapter.sol
+++ b/contracts/adapters/UniswapRepayAdapter.sol
@@ -76,6 +76,40 @@ contract UniswapRepayAdapter is BaseUniswapAdapter, IFlashLoanReceiver {
     return true;
   }
 
+  function swapAndRepay(
+    address collateralAsset,
+    address debtAsset,
+    uint256 collateralAmount,
+    uint256 debtRepayAmount,
+    uint256 debtRateMode,
+    PermitSignature calldata permitSignature
+  ) external {
+    ReserveLogic.ReserveData memory reserveData = _getReserveData(collateralAsset);
+
+    if (collateralAsset != debtAsset) {
+      // Get exact collateral needed for the swap to avoid leftovers
+      uint256[] memory amounts = _getAmountsIn(collateralAsset, debtAsset, debtRepayAmount);
+      require(amounts[0] <= collateralAmount, 'slippage too high');
+
+      // Pull aTokens from user
+      _pullAToken(collateralAsset, reserveData.aTokenAddress, msg.sender, amounts[0], permitSignature);
+
+      // Swap collateral for debt asset
+      _swapTokensForExactTokens(collateralAsset, debtAsset, amounts[0], debtRepayAmount);
+    } else {
+      // Pull aTokens from user
+      _pullAToken(collateralAsset, reserveData.aTokenAddress, msg.sender, debtRepayAmount, permitSignature);
+    }
+
+    // Repay debt
+    IERC20(debtAsset).approve(address(POOL), debtRepayAmount);
+    POOL.repay(debtAsset, debtRepayAmount, debtRateMode, msg.sender);
+
+    // In the case the repay amount provided exceeded the actual debt, send the leftovers to the user
+    _sendLeftovers(debtAsset, msg.sender);
+  }
+
+
   /**
    * @dev Perform the repay of the debt, pulls the initiator collateral and swaps to repay the flash loan
    *