Aave Swapper Updates (#353)

* feat: milkman updates

* chore: explicitly make bytes32(0)

src/swaps/AaveSwapper.sol

@@ -11,41 +11,28 @@ import {Initializable} from 'solidity-utils/contracts/transparent-proxy/Initiali
 import {AaveV3Ethereum} from 'aave-address-book/AaveV3Ethereum.sol';
 import {AaveGovernanceV2} from 'aave-address-book/AaveGovernanceV2.sol';
 
+import {IAaveSwapper} from './interfaces/IAaveSwapper.sol';
 import {IPriceChecker} from './interfaces/IExpectedOutCalculator.sol';
 import {IMilkman} from './interfaces/IMilkman.sol';
 
 /**
  * @title AaveSwapper
- * @author Llama
+ * @author efecarranza.eth
  * @notice Helper contract to swap assets using milkman
  */
-contract AaveSwapper is Initializable, OwnableWithGuardian, Rescuable {
+contract AaveSwapper is IAaveSwapper, Initializable, OwnableWithGuardian, Rescuable {
   using SafeERC20 for IERC20;
 
-  event SwapCanceled(address indexed fromToken, address indexed toToken, uint256 amount);
-  event SwapRequested(
-    address milkman,
-    address indexed fromToken,
-    address indexed toToken,
-    address fromOracle,
-    address toOracle,
-    uint256 amount,
-    address indexed recipient,
-    uint256 slippage
-  );
-
-  error Invalid0xAddress();
-  error InvalidAmount();
-  error InvalidRecipient();
-  error OracleNotSet();
-
+  /// @inheritdoc IAaveSwapper
   address public constant BAL80WETH20 = 0x5c6Ee304399DBdB9C8Ef030aB642B10820DB8F56;
 
+  /// @inheritdoc IAaveSwapper
   function initialize() external initializer {
     _transferOwnership(AaveGovernanceV2.SHORT_EXECUTOR);
     _updateGuardian(0xA519a7cE7B24333055781133B13532AEabfAC81b);
   }
 
+  /// @inheritdoc IAaveSwapper
   function swap(
     address milkman,
     address priceChecker,
@@ -70,6 +57,7 @@ contract AaveSwapper is Initializable, OwnableWithGuardian, Rescuable {
       IERC20(fromToken),
       IERC20(toToken),
       recipient,
+      bytes32(0),
       priceChecker,
       data
     );
@@ -86,6 +74,7 @@ contract AaveSwapper is Initializable, OwnableWithGuardian, Rescuable {
     );
   }
 
+  /// @inheritdoc IAaveSwapper
   function cancelSwap(
     address tradeMilkman,
     address priceChecker,
@@ -104,6 +93,7 @@ contract AaveSwapper is Initializable, OwnableWithGuardian, Rescuable {
       IERC20(fromToken),
       IERC20(toToken),
       recipient,
+      bytes32(0),
       priceChecker,
       data
     );
@@ -116,6 +106,7 @@ contract AaveSwapper is Initializable, OwnableWithGuardian, Rescuable {
     emit SwapCanceled(fromToken, toToken, amount);
   }
 
+  /// @inheritdoc IAaveSwapper
   function getExpectedOut(
     address priceChecker,
     uint256 amount,
@@ -137,17 +128,19 @@ contract AaveSwapper is Initializable, OwnableWithGuardian, Rescuable {
       );
   }
 
+  /// @inheritdoc Rescuable
   function whoCanRescue() public view override returns (address) {
     return owner();
   }
 
   /// @inheritdoc IRescuableBase
   function maxRescue(
     address erc20Token
-  ) public view override(RescuableBase, IRescuableBase) returns (uint256) {
+  ) public pure override(RescuableBase, IRescuableBase) returns (uint256) {
     return type(uint256).max;
   }
 
+  /// @dev Internal function to encode swap data
   function _getPriceCheckerAndData(
     address toToken,
     address fromOracle,
@@ -161,6 +154,7 @@ contract AaveSwapper is Initializable, OwnableWithGuardian, Rescuable {
     }
   }
 
+  /// @dev Internal function to encode data for price checker
   function _getChainlinkCheckerData(
     address fromOracle,
     address toOracle

src/swaps/interfaces/IAaveSwapper.sol

@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+interface IAaveSwapper {
+  /// @dev Emitted when a swap is canceled
+  /// @param fromToken The token to swap from
+  /// @param toToken The token to swap to
+  /// @param amount Amount of fromToken to swap
+  event SwapCanceled(address indexed fromToken, address indexed toToken, uint256 amount);
+
+  /// @dev Emitted when a swap is submitted to Cow Swap
+  /// @param milkman Address of Milkman (Cow Swap) contract
+  /// @param fromToken Address of the token to swap from
+  /// @param toToken Address of the token to swap to
+  /// @param fromOracle Oracle to use for price validation for fromToken
+  /// @param toOracle Oracle to use for price validation for toToken
+  /// @param recipient Address receiving the swap
+  /// @param amount Amount of fromToken to swap
+  /// @param slippage The allowed slippage for the swap
+  event SwapRequested(
+    address milkman,
+    address indexed fromToken,
+    address indexed toToken,
+    address fromOracle,
+    address toOracle,
+    uint256 amount,
+    address indexed recipient,
+    uint256 slippage
+  );
+
+  /// @dev Provided address cannot be the zero-address
+  error Invalid0xAddress();
+
+  /// @dev Amount has to be greater than zero
+  error InvalidAmount();
+
+  /// @dev Recipient cannot be the zero-address
+  error InvalidRecipient();
+
+  /// @dev Oracle has not be set
+  error OracleNotSet();
+
+  /// @notice Returns the address of the 80-BAL-20-WETH Balancer LP
+  function BAL80WETH20() external view returns (address);
+
+  /// @notice Initializes contract
+  function initialize() external;
+
+  /// @notice Performs a swap via Cow Swap
+  /// @param milkman Address of Milkman (Cow Swap) contract
+  /// @param priceChecker Address of price checker to use for swap
+  /// @param fromToken Address of the token to swap from
+  /// @param toToken Address of the token to swap to
+  /// @param fromOracle Oracle to use for price validation for fromToken
+  /// @param toOracle Oracle to use for price validation for toToken
+  /// @param recipient Address receiving the swap
+  /// @param amount Amount of fromToken to swap
+  /// @param slippage The allowed slippage for the swap
+  function swap(
+    address milkman,
+    address priceChecker,
+    address fromToken,
+    address toToken,
+    address fromOracle,
+    address toOracle,
+    address recipient,
+    uint256 amount,
+    uint256 slippage
+  ) external;
+
+  /// @notice Canceels a pending swap via Cow Swap
+  /// @param tradeMilkman Address of Milkman instance that holds funds in escrow
+  /// @param priceChecker Address of price checker to use for swap
+  /// @param fromToken Address of the token to swap from
+  /// @param toToken Address of the token to swap to
+  /// @param fromOracle Oracle to use for price validation for fromToken
+  /// @param toOracle Oracle to use for price validation for toToken
+  /// @param recipient Address receiving the swap
+  /// @param amount Amount of fromToken to swap
+  /// @param slippage The allowed slippage for the swap
+  function cancelSwap(
+    address tradeMilkman,
+    address priceChecker,
+    address fromToken,
+    address toToken,
+    address fromOracle,
+    address toOracle,
+    address recipient,
+    uint256 amount,
+    uint256 slippage
+  ) external;
+
+  /// @notice Returns the expected amount out in token to swap to
+  /// @param priceChecker Address of price checker to use for swap
+  /// @param amount Amount of fromToken to swap
+  /// @param fromToken Address of the token to swap from
+  /// @param toToken Address of the token to swap to
+  /// @param fromOracle Oracle to use for price validation for fromToken
+  /// @param toOracle Oracle to use for price validation for toToken
+  function getExpectedOut(
+    address priceChecker,
+    uint256 amount,
+    address fromToken,
+    address toToken,
+    address fromOracle,
+    address toOracle
+  ) external view returns (uint256);
+}

src/swaps/interfaces/IMilkman.sol

@@ -10,13 +10,15 @@ interface IMilkman {
   /// @param fromToken The token that the user wishes to sell.
   /// @param toToken The token that the user wishes to receive.
   /// @param to Who should receive the tokens.
+  /// @param appData The app data to be used in the CoW Protocol order.
   /// @param priceChecker A contract that verifies an order (mainly its minOut and fee) before Milkman signs it.
   /// @param priceCheckerData Data that gets passed to the price checker.
   function requestSwapExactTokensForTokens(
     uint256 amountIn,
     IERC20 fromToken,
     IERC20 toToken,
     address to,
+    bytes32 appData,
     address priceChecker,
     bytes calldata priceCheckerData
   ) external;
@@ -28,6 +30,7 @@ interface IMilkman {
     IERC20 fromToken,
     IERC20 toToken,
     address to,
+    bytes32 appData,
     address priceChecker,
     bytes calldata priceCheckerData
   ) external;