import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

class PushNotificationMessage {
  final String id;
  final String title;
  final String body;
  final String? type;
  final Map<String, dynamic> data;
  final DateTime timestamp;

  const PushNotificationMessage({
    required this.id,
    required this.title,
    required this.body,
    this.type,
    this.data = const {},
    required this.timestamp,
  });

  factory PushNotificationMessage.fromMap(Map<String, dynamic> map) {
    return PushNotificationMessage(
      id: map['id']?.toString() ?? UniqueKey().toString(),
      title: map['title']?.toString() ?? 'Notification',
      body: map['body']?.toString() ?? '',
      type: map['type']?.toString(),
      data: map['data'] is Map<String, dynamic> ? map['data'] as Map<String, dynamic> : {},
      timestamp: DateTime.now(),
    );
  }
}

abstract class NotificationService {
  Future<void> initialize();
  Future<String?> getDeviceToken();
  Stream<PushNotificationMessage> get onMessageReceived;
  Future<void> showInAppNotification(PushNotificationMessage message);
  void dispose();
}

class InAppNotificationService implements NotificationService {
  final _messageController = StreamController<PushNotificationMessage>.broadcast();
  final List<PushNotificationMessage> _history = [];
  bool _isInitialized = false;

  @override
  Future<void> initialize() async {
    _isInitialized = true;
    debugPrint('[NotificationService] In-App Fallback Notification Service initialized.');
  }

  @override
  Future<String?> getDeviceToken() async {
    // In-app fallback has no cloud device push token
    return null;
  }

  @override
  Stream<PushNotificationMessage> get onMessageReceived => _messageController.stream;

  List<PushNotificationMessage> get history => List.unmodifiable(_history);

  @override
  Future<void> showInAppNotification(PushNotificationMessage message) async {
    if (!_isInitialized) {
      await initialize();
    }
    _history.insert(0, message);
    if (_history.length > 50) {
      _history.removeLast();
    }
    _messageController.add(message);
    debugPrint('[NotificationService] In-app notification received: ${message.title} - ${message.body}');
  }

  @override
  void dispose() {
    _messageController.close();
  }
}

final notificationServiceProvider = Provider<NotificationService>((ref) {
  final service = InAppNotificationService();
  ref.onDispose(() => service.dispose());
  return service;
});