import webpush from 'web-push';
import logger from '@utils/logger';
import { Subscription } from '@models/Subscription';

type PushSubscription = any; // Web Push protocol JSON

class NotificationService {
  private userIdToSubscriptions: Map<string, PushSubscription[]> = new Map();

  configure(vapidPublicKey?: string, vapidPrivateKey?: string, mailto?: string) {
    const pub = vapidPublicKey || process.env.VAPID_PUBLIC_KEY || '';
    const priv = vapidPrivateKey || process.env.VAPID_PRIVATE_KEY || '';
    const contact = mailto || process.env.VAPID_CONTACT || 'mailto:admin@example.com';
    if (!pub || !priv) {
      logger.warn('VAPID keys are not configured. Push notifications are disabled.');
      return;
    }
    webpush.setVapidDetails(contact, pub, priv);
    logger.info('Web Push configured');
  }

  async addSubscription(userId: string, subscription: PushSubscription, userAgent?: string) {
    // Persist to DB (upsert by endpoint)
    try {
      const endpoint: string = subscription?.endpoint || '';
      const keys = subscription?.keys || {};
      if (!endpoint || !keys?.p256dh || !keys?.auth) throw new Error('Invalid subscription payload');
      await Subscription.upsert({
        userId,
        endpoint,
        p256dh: keys.p256dh,
        auth: keys.auth,
        userAgent: userAgent || null,
      } as any);
    } catch (e) {
      logger.error('Failed to persist subscription', e);
    }
    const list = this.userIdToSubscriptions.get(userId) || [];
    const already = list.find((s) => JSON.stringify(s) === JSON.stringify(subscription));
    if (!already) {
      list.push(subscription);
      this.userIdToSubscriptions.set(userId, list);
    }
    logger.info(`Subscription stored for user ${userId}. Total: ${list.length}`);
  }

  async sendToUsers(userIds: string[], payload: any) {
    const message = JSON.stringify(payload);
    for (const uid of userIds) {
      let subs = this.userIdToSubscriptions.get(uid) || [];
      // Load from DB if memory empty
      if (subs.length === 0) {
        try {
          const rows = await Subscription.findAll({ where: { userId: uid } });
          subs = rows.map((r: any) => ({ endpoint: r.endpoint, keys: { p256dh: r.p256dh, auth: r.auth } }));
        } catch {}
      }
      for (const sub of subs) {
        try {
          await webpush.sendNotification(sub, message);
        } catch (err) {
          logger.error(`Failed to send push to ${uid}:`, err);
        }
      }
    }
  }
}

export const notificationService = new NotificationService();
notificationService.configure();