import { storage } from '../storage';
import { webPushService } from '../services/web-push.service';
import { eventBus } from '../routes/shared';

const SYNC_PUSH_COOLDOWN_MS = 5 * 60 * 1000; // 5 minutes
const lastPushByOrganization = new Map<number, number>();

/**
 * Sends a silent web-push to subscribed devices in the organization
 * telling them to run an offline sync (delta sync) because task data changed.
 *
 * The push has no visible notification; the Service Worker catches the
 * `SYNC_NEEDED` payload and registers a background sync.
 *
 * Throttled to one push per organization per cooldown window, and skipped
 * for users that currently have an active SSE connection (their open app
 * will sync via SSE immediately).
 */
export async function pushSyncNeeded(organizationId: number): Promise<void> {
  try {
    const now = Date.now();
    const lastPush = lastPushByOrganization.get(organizationId);
    if (lastPush != null && now - lastPush < SYNC_PUSH_COOLDOWN_MS) {
      console.log(`[WebPush] pushSyncNeeded skipped for org ${organizationId}: cooldown active`);
      return;
    }

    const subscriptions = await storage.getWebPushSubscriptionsByOrganization(organizationId);
    if (subscriptions.length === 0) return;

    let sent = 0;
    let skipped = 0;
    for (const sub of subscriptions) {
      try {
        // Если у пользователя открыто приложение с активным SSE, пуш не нужен —
        // он и так получит task_updated и запустит синхронизацию.
        if (eventBus.isUserConnected(sub.userId, organizationId)) {
          skipped++;
          continue;
        }

        const subscription = JSON.parse(sub.subscription);
        const success = await webPushService.sendNotification(subscription, {
          type: 'SYNC_NEEDED',
          data: { organizationId },
        });
        if (success) sent++;
      } catch (err) {
        console.error('[WebPush] pushSyncNeeded single subscription error:', err);
      }
    }

    lastPushByOrganization.set(organizationId, now);
    console.log(`[WebPush] pushSyncNeeded org=${organizationId} sent=${sent} skipped_sse=${skipped}/${subscriptions.length}`);
  } catch (err) {
    console.error('[WebPush] pushSyncNeeded error:', err);
  }
}