cofounderella/lib/services/swipe_stream_service.dart

import 'dart:async';
import 'package:flutter/foundation.dart' show debugPrint, kDebugMode;
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import '../constants.dart';
import 'user_service.dart';

class SwipeStreamService {
  final FirebaseFirestore _firestore = FirebaseFirestore.instance;
  final List<String> _matchesInDB = [];

  StreamSubscription<List<DocumentSnapshot>>? _subscription;

  late String userId;
  late FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin;
  late bool matchesRead = false;

  // Singleton instance
  static final SwipeStreamService _instance = SwipeStreamService._internal();

  // Private constructor
  SwipeStreamService._internal();

  // Factory constructor
  factory SwipeStreamService() {
    return _instance;
  }

  // Initialization method
  void initialize(String userId, FlutterLocalNotificationsPlugin plugin) {
    _instance.userId = userId;
    _instance.flutterLocalNotificationsPlugin = plugin;
    // Reset old data
    _matchesInDB.clear();
    matchesRead = false;
  }

  Stream<List<DocumentSnapshot>> get swipesStream {
    return _firestore
        .collection(Constants.dbCollectionUsers)
        .doc(userId)
        .collection(Constants.dbCollectionMatches)
        .snapshots()
        .map((snapshot) => snapshot.docs);
  }

  void _showNotification(String swipeId) async {
    String matchName = await UserService.getUserName(swipeId);
    const AndroidNotificationDetails androidPlatformChannelSpecifics =
        AndroidNotificationDetails('new_matches_channel_id', 'new_match_info',
            channelShowBadge: true,
            visibility: NotificationVisibility.private,
            priority: Priority.high,
            showWhen: true);
    const NotificationDetails platformChannelSpecifics =
        NotificationDetails(android: androidPlatformChannelSpecifics);
    await flutterLocalNotificationsPlugin.show(0, 'New Match',
        'You have a new match with $matchName', platformChannelSpecifics,
        payload: swipeId);
  }

  void listenToSwipes() {
    _subscription = swipesStream.listen(
      (swipes) {
        if (!matchesRead) {
          for (var swipe in swipes) {
            if (kDebugMode) debugPrint('Init Match Notify --> ${swipe.id}');
            _matchesInDB.add(swipe.id);
          }
          matchesRead = true;
        } else {
          for (var swipe in swipes) {
            if (!_matchesInDB.contains(swipe.id)) {
              if (kDebugMode) debugPrint('NEW Match Notify --> ${swipe.id}');
              _matchesInDB.add(swipe.id);
              _showNotification(swipe.id);
            } else {
              if (kDebugMode) debugPrint('Old Match Notify --> ${swipe.id}');
            }
          }
        }
      },
    );
  }

  void stopListening() {
    _subscription?.cancel();
    _subscription = null;
  }

  void addUser(String userId) {
    if (!_matchesInDB.contains(userId)) {
      if (kDebugMode) debugPrint('Notify: SKIP Match Notify for --> $userId');
      _matchesInDB.add(userId);
    }
  }
}