feat: add dedicated eMode creation

Author: sakulstra

src/contracts/extensions/v3-config-engine/AaveV3ConfigEngine.sol

@@ -175,6 +175,17 @@ contract AaveV3ConfigEngine is IAaveV3ConfigEngine {
     );
   }
 
+  /// @inheritdoc IAaveV3ConfigEngine
+  function createEModeCategories(EModeCategoryCreation[] calldata creations) external {
+    EMODE_ENGINE.functionDelegateCall(
+      abi.encodeWithSelector(
+        EModeEngine.executeEModeCategoriesCreate.selector,
+        _getEngineConstants(),
+        creations
+      )
+    );
+  }
+
   /// @inheritdoc IAaveV3ConfigEngine
   function updateEModeCategories(EModeCategoryUpdate[] calldata updates) external {
     EMODE_ENGINE.functionDelegateCall(

src/contracts/extensions/v3-config-engine/AaveV3Payload.sol

@@ -42,6 +42,7 @@ abstract contract AaveV3Payload {
   function execute() external {
     _preExecute();
 
+    IEngine.EModeCategoryCreation[] memory newEmodes = eModeCategoryCreations();
     IEngine.EModeCategoryUpdate[] memory eModeCategories = eModeCategoriesUpdates();
     IEngine.Listing[] memory listings = newListings();
     IEngine.ListingWithCustomImpl[] memory listingsCustom = newListingsCustom();
@@ -52,6 +53,12 @@ abstract contract AaveV3Payload {
     IEngine.AssetEModeUpdate[] memory assetsEModes = assetsEModeUpdates();
     IEngine.CapsUpdate[] memory caps = capsUpdates();
 
+    if (newEmodes.length != 0) {
+      address(CONFIG_ENGINE).functionDelegateCall(
+        abi.encodeWithSelector(CONFIG_ENGINE.createEModeCategories.selector, newEmodes)
+      );
+    }
+
     if (eModeCategories.length != 0) {
       address(CONFIG_ENGINE).functionDelegateCall(
         abi.encodeWithSelector(CONFIG_ENGINE.updateEModeCategories.selector, eModeCategories)
@@ -143,6 +150,14 @@ abstract contract AaveV3Payload {
   /// @dev to be defined in the child with a list of priceFeeds to update
   function priceFeedsUpdates() public view virtual returns (IEngine.PriceFeedUpdate[] memory) {}
 
+  /// @dev to be defined in the child with a list of eMode categories to update
+  function eModeCategoryCreations()
+    public
+    view
+    virtual
+    returns (IEngine.EModeCategoryCreation[] memory)
+  {}
+
   /// @dev to be defined in the child with a list of eMode categories to update
   function eModeCategoriesUpdates()
     public

src/contracts/extensions/v3-config-engine/IAaveV3ConfigEngine.sol

@@ -219,6 +219,26 @@ interface IAaveV3ConfigEngine {
     string label;
   }
 
+  /**
+   * @dev Example (mock):
+   * EModeCategoryUpdate({
+   *   ltv: 60_00,
+   *   liqThreshold: 70_00,
+   *   liqBonus: EngineFlags.KEEP_CURRENT,
+   *   label: EngineFlags.KEEP_CURRENT_STRING,
+   *   borrowable:[USDC],
+   *   collaterals:[ETH]
+   * })
+   */
+  struct EModeCategoryCreation {
+    uint256 ltv;
+    uint256 liqThreshold;
+    uint256 liqBonus;
+    string label;
+    address[] borrowable;
+    address[] collaterals;
+  }
+
   /**
    * @dev Example (mock):
    * RateStrategyUpdate({
@@ -295,6 +315,13 @@ interface IAaveV3ConfigEngine {
    */
   function updateBorrowSide(BorrowUpdate[] memory updates) external;
 
+  /**
+   * @notice Performs an update of the e-mode categories, in the Aave pool configured in this engine instance
+   * @param creations `EModeCategoryCreation[]` list of declarative creations containing the new parameters
+   *   More information on the documentation of the struct.
+   */
+  function createEModeCategories(EModeCategoryCreation[] memory creations) external;
+
   /**
    * @notice Performs an update of the e-mode categories, in the Aave pool configured in this engine instance
    * @param updates `EModeCategoryUpdate[]` list of declarative updates containing the new parameters

src/contracts/extensions/v3-config-engine/libraries/EModeEngine.sol

@@ -11,6 +11,8 @@ library EModeEngine {
   using PercentageMath for uint256;
   using SafeCast for uint256;
 
+  error NoAvailableEmodeCategory();
+
   function executeAssetsEModeUpdate(
     IEngine.EngineConstants calldata engineConstants,
     IEngine.AssetEModeUpdate[] memory updates
@@ -20,6 +22,38 @@ library EModeEngine {
     _configAssetsEMode(engineConstants.poolConfigurator, updates);
   }
 
+  function executeEModeCategoriesCreate(
+    IEngine.EngineConstants calldata engineConstants,
+    IEngine.EModeCategoryCreation[] memory creations
+  ) external {
+    for (uint256 i; i < creations.length; i++) {
+      uint8 categoryId = _findFirstUnusedEmodeCategory(engineConstants.pool);
+      engineConstants.poolConfigurator.setEModeCategory(
+        categoryId,
+        creations[i].ltv.toUint16(),
+        creations[i].liqThreshold.toUint16(),
+        // For reference, this is to simplify the interaction with the Aave protocol,
+        // as there the definition is as e.g. 105% (5% bonus for liquidators)
+        (100_00 + creations[i].liqBonus).toUint16(),
+        creations[i].label
+      );
+      for (uint256 j; j < creations[i].collaterals.length; j++) {
+        engineConstants.poolConfigurator.setAssetCollateralInEMode(
+          creations[i].collaterals[j],
+          categoryId,
+          true
+        );
+      }
+      for (uint256 k; k < creations[i].borrowable.length; k++) {
+        engineConstants.poolConfigurator.setAssetBorrowableInEMode(
+          creations[i].borrowable[k],
+          categoryId,
+          true
+        );
+      }
+    }
+  }
+
   function executeEModeCategoriesUpdate(
     IEngine.EngineConstants calldata engineConstants,
     IEngine.EModeCategoryUpdate[] memory updates
@@ -114,4 +148,15 @@ library EModeEngine {
       }
     }
   }
+
+  /**
+   * @dev eModes must have a non-zero lt so we select the first that has a zero lt.
+   */
+  function _findFirstUnusedEmodeCategory(IPool pool) private view returns (uint8) {
+    // eMode id 0 is skipped intentially as it is the reserved default
+    for (uint8 i = 1; i < 256; i++) {
+      if (pool.getEModeCategoryCollateralConfig(i).liquidationThreshold == 0) return i;
+    }
+    revert NoAvailableEmodeCategory();
+  }
 }