OperatingModeFacet

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

import {AppStorage, OperatingMode, ADMIN_ROLE, GUARD_ROLE} from "../libs/LibAppStorage.sol";
import {RoleGuard} from "../shared/RoleGuard.sol";

// ═══════════════════════════════════════════════════════════════════════════════
// EVENTS
// ═══════════════════════════════════════════════════════════════════════════════

event OperatingModeChanged(OperatingMode indexed oldMode, OperatingMode indexed newMode, address indexed changedBy);

// ═══════════════════════════════════════════════════════════════════════════════
// FACET
// ═══════════════════════════════════════════════════════════════════════════════

/// @title OperatingModeFacet
/// @notice Manages bridge operating mode (Normal vs Guarded)
/// @dev Normal mode allows instant path for trusted/small transactions.
///      Guarded mode queues all transactions through timelock.
contract OperatingModeFacet is RoleGuard {
    // =========================================================================
    // Storage
    // =========================================================================

    /// @dev AppStorage at slot 0 - MUST be the only state variable
    AppStorage internal s;

    // =========================================================================
    // External Functions
    // =========================================================================

    /// @notice Enter guarded mode - all bridge-in transactions will be queued
    /// @dev Requires GUARD_ROLE. Idempotent (no-op if already guarded).
    /// @return changed True if mode was changed, false if already in Guarded mode
    function enterGuardedMode() external onlyRole(GUARD_ROLE) returns (bool changed) {
        OperatingMode oldMode = s.operatingMode;

        if (oldMode == OperatingMode.Guarded) {
            return false;
        }

        s.operatingMode = OperatingMode.Guarded;
        emit OperatingModeChanged(oldMode, OperatingMode.Guarded, msg.sender);
        return true;
    }

    /// @notice Enter normal mode - instant path available for eligible transactions
    /// @dev Can only be called by ADMIN role. Idempotent (no-op if already normal).
    /// @return changed True if mode was changed, false if already in Normal mode
    function enterNormalMode() external onlyRole(ADMIN_ROLE) returns (bool changed) {
        OperatingMode oldMode = s.operatingMode;

        if (oldMode == OperatingMode.Normal) {
            return false;
        }

        s.operatingMode = OperatingMode.Normal;
        emit OperatingModeChanged(oldMode, OperatingMode.Normal, msg.sender);
        return true;
    }

    /// @notice Get the current operating mode
    /// @return The current operating mode (Normal or Guarded)
    function getOperatingMode() external view returns (OperatingMode) {
        return s.operatingMode;
    }
}