Feat: FeedSwitch V2

src/util/FeedSwitchV2.sol

@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.18;
+
+import "src/interfaces/IChainlinkFeed.sol";
+
+
+/// @title FeedSwitch
+/// @notice A contract to switch between feeds after a timelock period
+/// @dev The switch can only be initiated by the guardian and will be effective after the timelock period has passed, which could be zero.
+/// If the switch is initiated but not yet effective, it can be cancelled by the guardian without timelock period (if is not zero).
+/// The guardian can initiate the switch again to the previous feed multiple times.
+contract FeedSwitchV2 {
+    error NotGuardian();
+    error NotGov();
+    error NotPendingGov();
+    error FeedDecimalsMismatch();
+
+    address public pendingGov;
+    address public gov;
+    uint256 public timelockPeriod;
+    IChainlinkFeed public feed;
+    IChainlinkFeed public previousFeed;
+
+    uint256 public switchCompletedAt;
+
+    mapping(address => bool) public isGuardian;
+
+    IChainlinkFeed public immutable initialFeed;
+    IChainlinkFeed public immutable fallbackFeed;
+
+    event FeedSwitchInitiated(address indexed newFeed, uint256 effectiveAt);
+    event NewPendingGov(address indexed pendingGov);
+    event GovChanged(address indexed newGov);
+    event GuardianSet(address indexed guardian, bool isGuardian);
+    event TimelockPeriodChanged(uint256 newTimelockPeriod);
+
+    constructor(
+        address _initialFeed,
+        address _fallbackFeed,
+        uint256 _timelockPeriod,
+        address _gov,
+        address _guardian
+    ) {
+        feed = IChainlinkFeed(_initialFeed);
+        initialFeed = IChainlinkFeed(_initialFeed);
+        fallbackFeed = IChainlinkFeed(_fallbackFeed);
+        if (
+            fallbackFeed.decimals() != 18 ||
+            feed.decimals() != 18
+        ) revert FeedDecimalsMismatch();
+
+        timelockPeriod = _timelockPeriod;
+        gov = _gov;
+        isGuardian[_guardian] = true;
+    }
+
+    modifier onlyGov() {
+        if (msg.sender != gov) revert NotGov();
+        _;
+    }
+
+    /// @notice Toggle the feed switch, entering or exiting the timelock period
+    /// @dev Can only be called by the guardian
+    function toggleFeedSwitch() external {
+        if (!isGuardian[msg.sender]) revert NotGuardian();
+
+        if (switchCompletedAt < block.timestamp) {
+            switchCompletedAt = block.timestamp + timelockPeriod;
+        } else switchCompletedAt = 0;
+
+        if (address(feed) == address(initialFeed)) {
+            feed = fallbackFeed;
+            previousFeed = initialFeed;
+        } else {
+            feed = initialFeed;
+            previousFeed = fallbackFeed;
+        }
+
+        emit FeedSwitchInitiated(address(feed), switchCompletedAt > 0 ? switchCompletedAt : block.timestamp);
+    }
+
+    /// @notice Get the current feed data
+    /// @return roundId The round ID
+    /// @return price The price of the asset
+    /// @return startedAt The timestamp of the start of the round
+    /// @return updatedAt The timestamp of the last update
+    /// @return answeredInRound The round ID in which the price was answered
+    function latestRoundData()
+        public
+        view
+        returns (
+            uint80 roundId,
+            int256 price,
+            uint256 startedAt,
+            uint256 updatedAt,
+            uint80 answeredInRound
+        )
+    {
+       if (block.timestamp >= switchCompletedAt) {
+            return feed.latestRoundData();
+        } else {
+            return previousFeed.latestRoundData();
+        }
+    }
+
+    /// @notice Get the latest price of the asset
+    /// @return price The price of the asset
+    function latestAnswer() external view returns (int256) {
+        (, int256 latestPrice, , , ) = latestRoundData();
+        return latestPrice;
+    }
+
+    /// @notice Get the number of decimals of the feed
+    /// @return decimals The number of decimals
+    function decimals() external pure returns (uint8) {
+        return 18;
+    }
+
+    /// @notice Check if the feed switch is queued
+    /// @dev If not queued, will return 0 as time left
+    /// @return timeLeft The time left for the switch to be effective
+    function isFeedSwitchQueued() external view returns (uint256) {
+        bool isQueued = block.timestamp < switchCompletedAt;
+        if (!isQueued) return 0;
+        else return switchCompletedAt - block.timestamp;
+    }
+
+    /// @notice Set a new pending governance
+    /// @dev Can only be called by the current governance, the new pending governance must call acceptGov to become the new governance
+    /// @param _pendingGov The address of the new pending governance
+    function setPendingGov(address _pendingGov) external onlyGov {
+        pendingGov = _pendingGov;
+        emit NewPendingGov(_pendingGov);
+    }
+
+    /// @notice Accept the governance role
+    /// @dev Can only be called by the pending governance
+    function acceptGov() external {
+        if (msg.sender != pendingGov) revert NotPendingGov();
+        gov = pendingGov;
+        pendingGov = address(0);
+        emit GovChanged(gov);
+    }
+
+    /// @notice Set the guardian role for an address
+    /// @dev Can only be called by the governance
+    /// @param guardianAddr The address to set the guardian role for
+    /// @param _isGuardian Whether the address should be a guardian
+    function setGuardian(address guardianAddr, bool _isGuardian) external onlyGov {
+        isGuardian[guardianAddr] = _isGuardian;
+        emit GuardianSet(guardianAddr, _isGuardian);
+    }
+
+    /// @notice Set a new timelock period
+    /// @dev Can only be called by the governance
+    /// @param _timelockPeriod The new timelock period in seconds
+    function setTimelockPeriod(uint256 _timelockPeriod) external onlyGov {
+        timelockPeriod = _timelockPeriod;
+        emit TimelockPeriodChanged(_timelockPeriod);
+    }
+}