feat: implement smart foreground quota refresh with debounce

- Trigger immediate quota poll when main window gains focus.
- Add 10s debounce to prevent API spam on frequent window switching.
- Add concurrency guard to prevent overlapping poll requests.
- Reset background polling interval after manual refresh.
- Add unit tests for polling, debounce, and concurrency logic.

src/services/CloudMonitorService.ts

@@ -6,17 +6,28 @@ import { logger } from '../utils/logger';
 export class CloudMonitorService {
   private static intervalId: NodeJS.Timeout | null = null;
   private static POLL_INTERVAL = 1000 * 60 * 5; // 5 minutes
+  private static DEBOUNCE_TIME = 10000; // 10 seconds
+  private static lastFocusTime: number = 0;
+  private static isPolling: boolean = false;
+
+  // Helper for testing
+  static resetStateForTesting() {
+    this.lastFocusTime = 0;
+    this.isPolling = false;
+    this.stop();
+  }
 
   static start() {
     if (this.intervalId) return;
     logger.info('Starting CloudMonitorService...');
 
+    // Set lastFocusTime to now to prevent "double-dip" on startup (focus event immediately after start)
+    this.lastFocusTime = Date.now();
+
     // Initial Poll
     this.poll().catch((e) => logger.error('Initial poll failed', e));
 
-    this.intervalId = setInterval(() => {
-      this.poll().catch((e) => logger.error('Scheduled poll failed', e));
-    }, this.POLL_INTERVAL);
+    this.startInterval();
   }
 
   static stop() {
@@ -27,40 +38,95 @@ export class CloudMonitorService {
     }
   }
 
-  static async poll() {
-    logger.info('CloudMonitor: Polling quotas...');
-    const accounts = await CloudAccountRepo.getAccounts();
-    const now = Math.floor(Date.now() / 1000);
+  /**
+   * Called when the application window gains focus.
+   * Triggers an immediate poll if not rate-limited by debounce.
+   */
+  static async handleAppFocus() {
+    const now = Date.now();
 
-    for (const account of accounts) {
-      try {
-        // 1. Check/Refresh Token if needed (give it a 10 min buffer here for safety)
-        let accessToken = account.token.access_token;
-        if (account.token.expiry_timestamp < now + 600) {
-          logger.info(`Monitor: Refreshing token for ${account.email}`);
-          const newToken = await GoogleAPIService.refreshAccessToken(account.token.refresh_token);
-          account.token.access_token = newToken.access_token;
-          account.token.expires_in = newToken.expires_in;
-          account.token.expiry_timestamp = now + newToken.expires_in;
-          await CloudAccountRepo.updateToken(account.id, account.token);
-          accessToken = newToken.access_token;
-        }
-
-        // 2. Fetch Quota
-        // We delay slightly between requests to act human/avoid spike
-        await new Promise((r) => setTimeout(r, 1000));
-        const quota = await GoogleAPIService.fetchQuota(accessToken);
-
-        // 3. Update DB
-        await CloudAccountRepo.updateQuota(account.id, quota);
-        await CloudAccountRepo.updateLastUsed(account.id);
-      } catch (error) {
-        logger.error(`Monitor: Failed to update ${account.email}`, error);
-        // Could mark status as 'error' or 'rate_limited' if 429
-      }
+    // 1. Concurrency Guard: If we are already polling, don't pile up requests
+    if (this.isPolling) {
+      logger.info('Monitor: App focused, but polling is already in progress. Skipping.');
+      return;
     }
 
-    // 4. Check for Auto-Switch
-    await AutoSwitchService.checkAndSwitchIfNeeded();
+    // 2. Debounce: If we focused recently, don't poll again
+    if (now - this.lastFocusTime < this.DEBOUNCE_TIME) {
+      logger.info('Monitor: App focused, skipping poll (debounce active).');
+      return;
+    }
+
+    logger.info('Monitor: App focused, triggering immediate poll...');
+    this.lastFocusTime = now;
+
+    // 3. Trigger Poll
+    await this.poll().catch((e) => {
+      logger.error('Monitor: Focus poll failed', e);
+    });
+    // 4. Reset the background interval so we don't double-poll shortly after
+    this.resetInterval();
+  }
+
+  private static startInterval() {
+    if (this.intervalId) {
+      clearInterval(this.intervalId);
+    }
+    this.intervalId = setInterval(() => {
+      this.poll().catch((e) => logger.error('Scheduled poll failed', e));
+    }, this.POLL_INTERVAL);
+  }
+
+  private static resetInterval() {
+    if (this.intervalId) {
+      clearInterval(this.intervalId);
+      this.startInterval(); // Restart the 5-minute timer
+    }
+  }
+
+  static async poll() {
+    if (this.isPolling) {
+      return; // Extra safety
+    }
+    this.isPolling = true;
+
+    try {
+      logger.info('CloudMonitor: Polling quotas...');
+      const accounts = await CloudAccountRepo.getAccounts();
+      const now = Math.floor(Date.now() / 1000);
+
+      for (const account of accounts) {
+        try {
+          // 1. Check/Refresh Token if needed (give it a 10 min buffer here for safety)
+          let accessToken = account.token.access_token;
+          if (account.token.expiry_timestamp < now + 600) {
+            logger.info(`Monitor: Refreshing token for ${account.email}`);
+            const newToken = await GoogleAPIService.refreshAccessToken(account.token.refresh_token);
+            account.token.access_token = newToken.access_token;
+            account.token.expires_in = newToken.expires_in;
+            account.token.expiry_timestamp = now + newToken.expires_in;
+            await CloudAccountRepo.updateToken(account.id, account.token);
+            accessToken = newToken.access_token;
+          }
+
+          // 2. Fetch Quota
+          // We delay slightly between requests to act human/avoid spike
+          await new Promise((r) => setTimeout(r, 1000));
+          const quota = await GoogleAPIService.fetchQuota(accessToken);
+
+          // 3. Update DB
+          await CloudAccountRepo.updateQuota(account.id, quota);
+          await CloudAccountRepo.updateLastUsed(account.id);
+        } catch (error) {
+          logger.error(`Monitor: Failed to update ${account.email}`, error);
+          // Could mark status as 'error' or 'rate_limited' if 429
+        }
+      }
+
+      // 4. Check for Auto-Switch
+      await AutoSwitchService.checkAndSwitchIfNeeded();
+    } finally {
+      this.isPolling = false;
+    }
   }
 }