Merge pull request #10 from rndquu/feat/collateral-twap

refactor: refactor UbiquityPool

packages/contracts/package.json

@@ -14,7 +14,6 @@
     "url": "https://github.com/ubiquity/ubiquity-dollar.git"
   },
   "dependencies": {
-    "@chainlink/contracts": "^0.8.0",
     "@types/command-line-args": "5.2.0",
     "command-line-args": "5.2.1",
     "dotenv": "^16.0.3",

packages/contracts/src/dollar/facets/UbiquityPoolFacet.sol

@@ -136,9 +136,14 @@ contract UbiquityPoolFacet is IUbiquityPool, Modifiers {
     /// @inheritdoc IUbiquityPool
     function addCollateralToken(
         address collateralAddress,
+        address chainLinkPriceFeedAddress,
         uint256 poolCeiling
     ) external onlyAdmin {
-        LibUbiquityPool.addCollateralToken(collateralAddress, poolCeiling);
+        LibUbiquityPool.addCollateralToken(
+            collateralAddress,
+            chainLinkPriceFeedAddress,
+            poolCeiling
+        );
     }
 
     /// @inheritdoc IUbiquityPool
@@ -147,21 +152,15 @@ contract UbiquityPoolFacet is IUbiquityPool, Modifiers {
     }
 
     /// @inheritdoc IUbiquityPool
-    function setCollateralPrice(
-        uint256 collateralIndex,
-        uint256 newPrice
-    ) external onlyAdmin {
-        LibUbiquityPool.setCollateralPrice(collateralIndex, newPrice);
-    }
-
-    /// @inheritdoc IUbiquityPool
-    function setCollateralChainLinkPriceFeedAddress(
+    function setCollateralChainLinkPriceFeed(
         address collateralAddress,
-        address chainLinkPriceFeedAddress
+        address chainLinkPriceFeedAddress,
+        uint256 stalenessThreshold
     ) external onlyAdmin {
-        LibUbiquityPool.setCollateralChainLinkPriceFeedAddress(
+        LibUbiquityPool.setCollateralChainLinkPriceFeed(
             collateralAddress,
-            chainLinkPriceFeedAddress
+            chainLinkPriceFeedAddress,
+            stalenessThreshold
         );
     }
 

packages/contracts/src/dollar/interfaces/IUbiquityPool.sol

@@ -142,10 +142,12 @@ interface IUbiquityPool {
     /**
      * @notice Adds a new collateral token
      * @param collateralAddress Collateral token address
+     * @param chainLinkPriceFeedAddress Chainlink's price feed address
      * @param poolCeiling Max amount of available tokens for collateral
      */
     function addCollateralToken(
         address collateralAddress,
+        address chainLinkPriceFeedAddress,
         uint256 poolCeiling
     ) external;
 
@@ -156,23 +158,15 @@ interface IUbiquityPool {
     function removeAmoMinter(address amoMinterAddress) external;
 
     /**
-     * @notice Sets collateral token price in USD
-     * @param collateralIndex Collateral token index
-     * @param newPrice New USD price (precision 1e6)
-     */
-    function setCollateralPrice(
-        uint256 collateralIndex,
-        uint256 newPrice
-    ) external;
-
-    /**
-     * @notice Sets collateral ChainLink price feed address
+     * @notice Sets collateral ChainLink price feed params
      * @param collateralAddress Collateral token address
      * @param chainLinkPriceFeedAddress ChainLink price feed address
+     * @param stalenessThreshold Threshold in seconds when chainlink answer should be considered stale
      */
-    function setCollateralChainLinkPriceFeedAddress(
+    function setCollateralChainLinkPriceFeed(
         address collateralAddress,
-        address chainLinkPriceFeedAddress
+        address chainLinkPriceFeedAddress,
+        uint256 stalenessThreshold
     ) external;
 
     /**

packages/contracts/src/dollar/libraries/LibUbiquityPool.sol

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 pragma solidity 0.8.19;
 
+import {AggregatorV3Interface} from "@chainlink/interfaces/AggregatorV3Interface.sol";
 import {ERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
 import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
@@ -10,7 +11,6 @@ import {IERC20Ubiquity} from "../interfaces/IERC20Ubiquity.sol";
 import {UBIQUITY_POOL_PRICE_PRECISION} from "./Constants.sol";
 import {LibAppStorage} from "./LibAppStorage.sol";
 import {LibTWAPOracle} from "./LibTWAPOracle.sol";
-import {AggregatorV3Interface} from "@chainlink/interfaces/AggregatorV3Interface.sol";
 
 /**
  * @notice Ubiquity pool library
@@ -42,7 +42,11 @@ library LibUbiquityPool {
         address[] collateralAddresses;
         // collateral address -> collateral index
         mapping(address collateralAddress => uint256 collateralIndex) collateralIndex;
-        // Stores price of the collateral
+        // collateral index -> chainlink price feed addresses
+        address[] collateralPriceFeedAddresses;
+        // collateral index -> threshold in seconds when chainlink answer should be considered stale
+        uint256[] collateralPriceFeedStalenessThresholds;
+        // collateral index -> collateral price
         uint256[] collateralPrices;
         // array collateral symbols
         string[] collateralSymbols;
@@ -83,15 +87,15 @@ library LibUbiquityPool {
         bool[] isMintPaused;
         // whether redeeming is paused for a particular collateral index
         bool[] isRedeemPaused;
-        // Collateral price feed contract address
-        address[] collateralPriceFeedAddresses;
     }
 
     /// @notice Struct used for detailed collateral information
     struct CollateralInformation {
         uint256 index;
         string symbol;
         address collateralAddress;
+        address collateralPriceFeedAddress;
+        uint256 collateralPriceFeedStalenessThreshold;
         bool isEnabled;
         uint256 missingDecimals;
         uint256 price;
@@ -126,13 +130,14 @@ library LibUbiquityPool {
     event AmoMinterAdded(address amoMinterAddress);
     /// @notice Emitted when AMO minter is removed
     event AmoMinterRemoved(address amoMinterAddress);
-    /// @notice Emitted on setting a collateral price
-    event CollateralPriceSet(uint256 collateralIndex, uint256 newPrice);
-    /// @notice Emitted on setting a collateral price feed address
+    /// @notice Emitted on setting a chainlink's collateral price feed params
     event CollateralPriceFeedSet(
         uint256 collateralIndex,
-        address priceFeedAddress
+        address priceFeedAddress,
+        uint256 stalenessThreshold
     );
+    /// @notice Emitted on setting a collateral price
+    event CollateralPriceSet(uint256 collateralIndex, uint256 newPrice);
     /// @notice Emitted on enabling/disabling a particular collateral token
     event CollateralToggled(uint256 collateralIndex, bool newState);
     /// @notice Emitted when fees are updated
@@ -221,6 +226,8 @@ library LibUbiquityPool {
             index,
             poolStorage.collateralSymbols[index],
             collateralAddress,
+            poolStorage.collateralPriceFeedAddresses[index],
+            poolStorage.collateralPriceFeedStalenessThresholds[index],
             poolStorage.isCollateralEnabled[collateralAddress],
             poolStorage.missingDecimals[index],
             poolStorage.collateralPrices[index],
@@ -333,6 +340,8 @@ library LibUbiquityPool {
             "Minting is paused"
         );
 
+        // update Dollar price from Curve's Dollar Metapool
+        LibTWAPOracle.update();
         // prevent unnecessary mints
         require(
             getDollarPriceUsd() >= poolStorage.mintPriceThreshold,
@@ -341,7 +350,8 @@ library LibUbiquityPool {
 
         // update collateral price
         updateChainLinkCollateralPrice(collateralIndex);
-        // get amount of collateral for incoming Dollars
+
+        // get amount of collateral for minting Dollars
         collateralNeeded = getDollarInCollateral(collateralIndex, dollarAmount);
 
         // subtract the minting fee
@@ -402,6 +412,8 @@ library LibUbiquityPool {
             "Redeeming is paused"
         );
 
+        // update Dollar price from Curve's Dollar Metapool
+        LibTWAPOracle.update();
         // prevent unnecessary redemptions that could adversely affect the Dollar price
         require(
             getDollarPriceUsd() <= poolStorage.redeemPriceThreshold,
@@ -416,9 +428,10 @@ library LibUbiquityPool {
             )
             .div(UBIQUITY_POOL_PRICE_PRECISION);
 
-        //update collateral price
+        // update collateral price
         updateChainLinkCollateralPrice(collateralIndex);
 
+        // get collateral output for incoming Dollars
         collateralOut = getDollarInCollateral(collateralIndex, dollarAfterFee);
 
         // checks
@@ -503,6 +516,51 @@ library LibUbiquityPool {
         }
     }
 
+    /**
+     * @notice Updates collateral token price in USD from ChainLink price feed
+     * @param collateralIndex Collateral token index
+     */
+    function updateChainLinkCollateralPrice(uint256 collateralIndex) internal {
+        UbiquityPoolStorage storage poolStorage = ubiquityPoolStorage();
+
+        AggregatorV3Interface priceFeed = AggregatorV3Interface(
+            poolStorage.collateralPriceFeedAddresses[collateralIndex]
+        );
+
+        // fetch latest price
+        (
+            ,
+            // roundId
+            int256 answer, // startedAt
+            ,
+            uint256 updatedAt,
+
+        ) = // answeredInRound
+            priceFeed.latestRoundData();
+
+        // fetch number of decimals in chainlink feed
+        uint256 priceFeedDecimals = priceFeed.decimals();
+
+        // validation
+        require(answer > 0, "Invalid price");
+        require(
+            block.timestamp - updatedAt <
+                poolStorage.collateralPriceFeedStalenessThresholds[
+                    collateralIndex
+                ],
+            "Stale data"
+        );
+
+        // convert chainlink price to 6 decimals
+        uint256 price = uint256(answer).mul(UBIQUITY_POOL_PRICE_PRECISION).div(
+            10 ** priceFeedDecimals
+        );
+
+        poolStorage.collateralPrices[collateralIndex] = price;
+
+        emit CollateralPriceSet(collateralIndex, price);
+    }
+
     //=========================
     // AMO minters functions
     //=========================
@@ -565,10 +623,12 @@ library LibUbiquityPool {
     /**
      * @notice Adds a new collateral token
      * @param collateralAddress Collateral token address
+     * @param chainLinkPriceFeedAddress Chainlink's price feed address
      * @param poolCeiling Max amount of available tokens for collateral
      */
     function addCollateralToken(
         address collateralAddress,
+        address chainLinkPriceFeedAddress,
         uint256 poolCeiling
     ) internal {
         UbiquityPoolStorage storage poolStorage = ubiquityPoolStorage();
@@ -607,11 +667,16 @@ library LibUbiquityPool {
         poolStorage.isRedeemPaused.push(false);
         poolStorage.isBorrowPaused.push(false);
 
-        // pool ceiling
+        // set pool ceiling
         poolStorage.poolCeilings.push(poolCeiling);
 
-        // price feed
-        poolStorage.collateralPriceFeedAddresses.push(address(0));
+        // set price feed address
+        poolStorage.collateralPriceFeedAddresses.push(
+            chainLinkPriceFeedAddress
+        );
+
+        // set price feed staleness threshold in seconds
+        poolStorage.collateralPriceFeedStalenessThresholds.push(1 days);
     }
 
     /**
@@ -627,66 +692,37 @@ library LibUbiquityPool {
     }
 
     /**
-     * @notice Sets exact collateral token price in USD
-     * @param collateralIndex Collateral token index
-     * @param newPrice New USD price (precision 1e6)
-     */
-    function setCollateralPrice(
-        uint256 collateralIndex,
-        uint256 newPrice
-    ) internal {
-        UbiquityPoolStorage storage poolStorage = ubiquityPoolStorage();
-
-        poolStorage.collateralPrices[collateralIndex] = newPrice;
-
-        emit CollateralPriceSet(collateralIndex, newPrice);
-    }
-
-    /**
-     * @notice Sets collateral ChainLink price feed address
+     * @notice Sets collateral ChainLink price feed params
      * @param collateralAddress Collateral token address
      * @param chainLinkPriceFeedAddress ChainLink price feed address
+     * @param stalenessThreshold Threshold in seconds when chainlink answer should be considered stale
      */
-    function setCollateralChainLinkPriceFeedAddress(
+    function setCollateralChainLinkPriceFeed(
         address collateralAddress,
-        address chainLinkPriceFeedAddress
+        address chainLinkPriceFeedAddress,
+        uint256 stalenessThreshold
     ) internal {
         UbiquityPoolStorage storage poolStorage = ubiquityPoolStorage();
 
         uint256 collateralIndex = poolStorage.collateralIndex[
             collateralAddress
         ];
+
+        // set price feed address
         poolStorage.collateralPriceFeedAddresses[
             collateralIndex
         ] = chainLinkPriceFeedAddress;
 
-        emit CollateralPriceFeedSet(collateralIndex, chainLinkPriceFeedAddress);
-    }
-
-    /**
-     * @notice Updates collateral token price in USD from ChainLink price feed
-     * @param collateralIndex Collateral token index
-     */
-    function updateChainLinkCollateralPrice(uint256 collateralIndex) internal {
-        UbiquityPoolStorage storage poolStorage = ubiquityPoolStorage();
+        // set staleness threshold in seconds when chainlink answer should be considered stale
+        poolStorage.collateralPriceFeedStalenessThresholds[
+            collateralIndex
+        ] = stalenessThreshold;
 
-        AggregatorV3Interface priceFeed = AggregatorV3Interface(
-            poolStorage.collateralPriceFeedAddresses[collateralIndex]
-        );
-        (
-            uint80 roundID,
-            int256 price,
-            ,
-            uint256 updatedAt,
-            uint80 answeredInRound
-        ) = priceFeed.latestRoundData();
-        require(
-            price >= 0 && updatedAt != 0 && answeredInRound >= roundID,
-            "Invalid ChainLink price"
+        emit CollateralPriceFeedSet(
+            collateralIndex,
+            chainLinkPriceFeedAddress,
+            stalenessThreshold
         );
-
-        poolStorage.collateralPrices[collateralIndex] = uint256(price);
-        emit CollateralPriceSet(collateralIndex, uint256(price));
     }
 
     /**