Adaptation of Repay with Collateral contract for Aave V2

src/core/contracts/flashloan/base/FlashLoanSimpleReceiverBase.sol

@@ -19,3 +19,17 @@ abstract contract FlashLoanSimpleReceiverBase is IFlashLoanSimpleReceiver {
     POOL = IPool(provider.getPool());
   }
 }
+
+interface IPoolAddressesProviderV2 {
+  function getLendingPool() external returns (address);
+}
+
+abstract contract FlashLoanSimpleReceiverBaseV2 is IFlashLoanSimpleReceiver {
+  IPoolAddressesProvider public immutable override ADDRESSES_PROVIDER;
+  IPool public immutable override POOL;
+
+  constructor(IPoolAddressesProvider provider) {
+    ADDRESSES_PROVIDER = provider;
+    POOL = IPool(IPoolAddressesProviderV2(address(provider)).getLendingPool());
+  }
+}

src/periphery/contracts/adapters/paraswap/BaseParaSwapAdapter.sol

@@ -2,7 +2,8 @@
 pragma solidity ^0.8.10;
 
 import {DataTypes} from 'aave-v3-core/contracts/protocol/libraries/types/DataTypes.sol';
-import {FlashLoanSimpleReceiverBase} from 'aave-v3-core/contracts/flashloan/base/FlashLoanSimpleReceiverBase.sol';
+import {FlashLoanSimpleReceiverBase, FlashLoanSimpleReceiverBaseV2} from 'aave-v3-core/contracts/flashloan/base/FlashLoanSimpleReceiverBase.sol';
+import {ILendingPool, DataTypes as DataTypesV2} from './interfaces/ILendingPool.sol';
 import {GPv2SafeERC20} from 'aave-v3-core/contracts/dependencies/gnosis/contracts/GPv2SafeERC20.sol';
 import {IERC20} from 'aave-v3-core/contracts/dependencies/openzeppelin/contracts/IERC20.sol';
 import {IERC20Detailed} from 'aave-v3-core/contracts/dependencies/openzeppelin/contracts/IERC20Detailed.sol';
@@ -17,7 +18,7 @@ import {Ownable} from 'aave-v3-core/contracts/dependencies/openzeppelin/contract
  * @notice Utility functions for adapters using ParaSwap
  * @author Jason Raymond Bell
  */
-abstract contract BaseParaSwapAdapter is FlashLoanSimpleReceiverBase, Ownable {
+abstract contract BaseParaSwapAdapter is FlashLoanSimpleReceiverBaseV2, Ownable {
   using SafeMath for uint256;
   using GPv2SafeERC20 for IERC20;
   using GPv2SafeERC20 for IERC20Detailed;
@@ -51,7 +52,7 @@ abstract contract BaseParaSwapAdapter is FlashLoanSimpleReceiverBase, Ownable {
 
   constructor(
     IPoolAddressesProvider addressesProvider
-  ) FlashLoanSimpleReceiverBase(addressesProvider) {
+  ) FlashLoanSimpleReceiverBaseV2(addressesProvider) {
     ORACLE = IPriceOracleGetter(addressesProvider.getPriceOracle());
   }
 
@@ -81,8 +82,8 @@ abstract contract BaseParaSwapAdapter is FlashLoanSimpleReceiverBase, Ownable {
    */
   function _getReserveData(
     address asset
-  ) internal view returns (DataTypes.ReserveDataLegacy memory) {
-    return POOL.getReserveData(asset);
+  ) internal view returns (DataTypesV2.ReserveData memory) {
+    return ILendingPool(address(POOL)).getReserveData(asset);
   }
 
   function _pullATokenAndWithdraw(

src/periphery/contracts/adapters/paraswap/BaseParaSwapBuyAdapter.sol

@@ -39,6 +39,7 @@ abstract contract BaseParaSwapBuyAdapter is BaseParaSwapAdapter {
    * @param maxAmountToSwap Max amount to be swapped
    * @param amountToReceive Amount to be received from the swap
    * @return amountSold The amount sold during the swap
+   * @return amountBought The amount bought during the swap
    */
   function _buyOnParaSwap(
     uint256 toAmountOffset,
@@ -47,7 +48,7 @@ abstract contract BaseParaSwapBuyAdapter is BaseParaSwapAdapter {
     IERC20Detailed assetToSwapTo,
     uint256 maxAmountToSwap,
     uint256 amountToReceive
-  ) internal returns (uint256 amountSold) {
+  ) internal returns (uint256 amountSold, uint256 amountBought) {
     (bytes memory buyCalldata, IParaSwapAugustus augustus) = abi.decode(
       paraswapData,
       (bytes, IParaSwapAugustus)
@@ -75,7 +76,6 @@ abstract contract BaseParaSwapBuyAdapter is BaseParaSwapAdapter {
     uint256 balanceBeforeAssetTo = assetToSwapTo.balanceOf(address(this));
 
     address tokenTransferProxy = augustus.getTokenTransferProxy();
-    assetToSwapFrom.safeApprove(tokenTransferProxy, 0);
     assetToSwapFrom.safeApprove(tokenTransferProxy, maxAmountToSwap);
 
     if (toAmountOffset != 0) {
@@ -101,12 +101,15 @@ abstract contract BaseParaSwapBuyAdapter is BaseParaSwapAdapter {
       }
     }
 
+    // Reset allowance
+    assetToSwapFrom.safeApprove(tokenTransferProxy, 0);
+
     uint256 balanceAfterAssetFrom = assetToSwapFrom.balanceOf(address(this));
     amountSold = balanceBeforeAssetFrom - balanceAfterAssetFrom;
     require(amountSold <= maxAmountToSwap, 'WRONG_BALANCE_AFTER_SWAP');
-    uint256 amountReceived = assetToSwapTo.balanceOf(address(this)).sub(balanceBeforeAssetTo);
-    require(amountReceived >= amountToReceive, 'INSUFFICIENT_AMOUNT_RECEIVED');
+    amountBought = assetToSwapTo.balanceOf(address(this)).sub(balanceBeforeAssetTo);
+    require(amountBought >= amountToReceive, 'INSUFFICIENT_AMOUNT_RECEIVED');
 
-    emit Bought(address(assetToSwapFrom), address(assetToSwapTo), amountSold, amountReceived);
+    emit Bought(address(assetToSwapFrom), address(assetToSwapTo), amountSold, amountBought);
   }
 }

src/periphery/contracts/adapters/paraswap/BaseParaSwapSellAdapter.sol

@@ -98,6 +98,7 @@ abstract contract BaseParaSwapSellAdapter is BaseParaSwapAdapter {
         revert(0, returndatasize())
       }
     }
+
     require(
       assetToSwapFrom.balanceOf(address(this)) == balanceBeforeAssetFrom - amountToSwap,
       'WRONG_BALANCE_AFTER_SWAP'

src/periphery/contracts/adapters/paraswap/ParaSwapRepayAdapter.sol

@@ -11,6 +11,7 @@ import {SafeMath} from 'aave-v3-core/contracts/dependencies/openzeppelin/contrac
 import {BaseParaSwapBuyAdapter} from './BaseParaSwapBuyAdapter.sol';
 import {IParaSwapAugustusRegistry} from './interfaces/IParaSwapAugustusRegistry.sol';
 import {IParaSwapAugustus} from './interfaces/IParaSwapAugustus.sol';
+import {DataTypes as DataTypesV2} from './interfaces/ILendingPool.sol';
 import {ReentrancyGuard} from '../../dependencies/openzeppelin/ReentrancyGuard.sol';
 
 /**
@@ -114,7 +115,7 @@ contract ParaSwapRepayAdapter is BaseParaSwapBuyAdapter, ReentrancyGuard {
     // Pull aTokens from user
     _pullATokenAndWithdraw(address(collateralAsset), msg.sender, collateralAmount, permitSignature);
     //buy debt asset using collateral asset
-    uint256 amountSold = _buyOnParaSwap(
+    (uint256 amountSold, uint256 amountBought) = _buyOnParaSwap(
       buyAllBalanceOffset,
       paraswapData,
       collateralAsset,
@@ -127,15 +128,23 @@ contract ParaSwapRepayAdapter is BaseParaSwapBuyAdapter, ReentrancyGuard {
 
     //deposit collateral back in the pool, if left after the swap(buy)
     if (collateralBalanceLeft > 0) {
-      IERC20(collateralAsset).safeApprove(address(POOL), 0);
       IERC20(collateralAsset).safeApprove(address(POOL), collateralBalanceLeft);
       POOL.deposit(address(collateralAsset), collateralBalanceLeft, msg.sender, 0);
+      IERC20(collateralAsset).safeApprove(address(POOL), 0);
     }
 
     // Repay debt. Approves 0 first to comply with tokens that implement the anti frontrunning approval fix
-    IERC20(debtAsset).safeApprove(address(POOL), 0);
     IERC20(debtAsset).safeApprove(address(POOL), debtRepayAmount);
     POOL.repay(address(debtAsset), debtRepayAmount, debtRateMode, msg.sender);
+    IERC20(debtAsset).safeApprove(address(POOL), 0);
+
+    {
+      //transfer excess of debtAsset back to the user, if any
+      uint256 debtAssetExcess = amountBought - debtRepayAmount;
+      if (debtAssetExcess > 0) {
+        IERC20(debtAsset).safeTransfer(msg.sender, debtAssetExcess);
+      }
+    }
   }
 
   /**
@@ -170,7 +179,7 @@ contract ParaSwapRepayAdapter is BaseParaSwapBuyAdapter, ReentrancyGuard {
       initiator
     );
 
-    uint256 amountSold = _buyOnParaSwap(
+    (uint256 amountSold, uint256 amountBought) = _buyOnParaSwap(
       buyAllBalanceOffset,
       paraswapData,
       collateralAsset,
@@ -180,9 +189,9 @@ contract ParaSwapRepayAdapter is BaseParaSwapBuyAdapter, ReentrancyGuard {
     );
 
     // Repay debt. Approves for 0 first to comply with tokens that implement the anti frontrunning approval fix.
-    IERC20(debtAsset).safeApprove(address(POOL), 0);
     IERC20(debtAsset).safeApprove(address(POOL), debtRepayAmount);
     POOL.repay(address(debtAsset), debtRepayAmount, rateMode, initiator);
+    IERC20(debtAsset).safeApprove(address(POOL), 0);
 
     uint256 neededForFlashLoanRepay = amountSold.add(premium);
 
@@ -194,6 +203,14 @@ contract ParaSwapRepayAdapter is BaseParaSwapBuyAdapter, ReentrancyGuard {
       permitSignature
     );
 
+    {
+      //transfer excess of debtAsset back to the user, if any
+      uint256 debtAssetExcess = amountBought - debtRepayAmount;
+      if (debtAssetExcess > 0) {
+        IERC20(debtAsset).safeTransfer(initiator, debtAssetExcess);
+      }
+    }
+
     // Repay flashloan. Approves for 0 first to comply with tokens that implement the anti frontrunning approval fix.
     IERC20(collateralAsset).safeApprove(address(POOL), 0);
     IERC20(collateralAsset).safeApprove(address(POOL), collateralAmount.add(premium));
@@ -206,7 +223,7 @@ contract ParaSwapRepayAdapter is BaseParaSwapBuyAdapter, ReentrancyGuard {
     uint256 debtRepayAmount,
     address initiator
   ) private view returns (uint256) {
-    DataTypes.ReserveDataLegacy memory debtReserveData = _getReserveData(address(debtAsset));
+    DataTypesV2.ReserveData memory debtReserveData = _getReserveData(address(debtAsset));
 
     address debtToken = DataTypes.InterestRateMode(rateMode) == DataTypes.InterestRateMode.STABLE
       ? debtReserveData.stableDebtTokenAddress

src/periphery/contracts/adapters/paraswap/interfaces/ILendingPool.sol

@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: ISC
+pragma solidity ^0.8.0;
+
+library DataTypes {
+  struct ReserveData {
+    //stores the reserve configuration
+    ReserveConfigurationMap configuration;
+    //the liquidity index. Expressed in ray
+    uint128 liquidityIndex;
+    //variable borrow index. Expressed in ray
+    uint128 variableBorrowIndex;
+    //the current supply rate. Expressed in ray
+    uint128 currentLiquidityRate;
+    //the current variable borrow rate. Expressed in ray
+    uint128 currentVariableBorrowRate;
+    //the current stable borrow rate. Expressed in ray
+    uint128 currentStableBorrowRate;
+    uint40 lastUpdateTimestamp;
+    //tokens addresses
+    address aTokenAddress;
+    address stableDebtTokenAddress;
+    address variableDebtTokenAddress;
+    //address of the interest rate strategy
+    address interestRateStrategyAddress;
+    //the id of the reserve. Represents the position in the list of the active reserves
+    uint8 id;
+  }
+
+  struct ReserveConfigurationMap {
+    //bit 0-15: LTV
+    //bit 16-31: Liq. threshold
+    //bit 32-47: Liq. bonus
+    //bit 48-55: Decimals
+    //bit 56: Reserve is active
+    //bit 57: reserve is frozen
+    //bit 58: borrowing is enabled
+    //bit 59: stable rate borrowing enabled
+    //bit 60-63: reserved
+    //bit 64-79: reserve factor
+    uint256 data;
+  }
+}
+
+interface ILendingPool {
+  /**
+   * @dev Returns the state and configuration of the reserve
+   * @param asset The address of the underlying asset of the reserve
+   * @return The state of the reserve
+   **/
+  function getReserveData(address asset) external view returns (DataTypes.ReserveData memory);
+}