import 'dart:convert';
import 'dart:developer';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:equatable/equatable.dart';
import 'package:http/http.dart' as http;
import 'package:shared_preferences/shared_preferences.dart';
import 'package:user_repository/user_repository.dart';
import 'package:prosappco/constansts.dart' show API_BASE_URL;

part 'notification_event.dart';
part 'notification_state.dart';

// Handles FCM messages when app is terminated/background
@pragma('vm:entry-point')
Future<void> firebaseMessagingBackgroundHandler(RemoteMessage message) async {
  // Local notification shown by the system tray automatically for data-only
  // messages; nothing extra needed here.
}

class NotificationBloc extends Bloc<NotificationEvent, NotificationState> {
  final Future<void> Function() requestLocalNotificationPermission;
  final void Function({
    required int id,
    String? title,
    String? body,
    String? data,
  }) showLocalNotification;

  NotificationBloc(
      {required this.requestLocalNotificationPermission,
      required this.showLocalNotification})
      : super(const NotificationState()) {
    on<NotificationStatusChanged>(_notificationStatusChanged);
  }

  void _notificationStatusChanged(
      NotificationStatusChanged event, Emitter<NotificationState> emit) {
    emit(state.copyWith(status: event.status));
  }

  // Call once after login to register the FCM token and listen for foreground messages.
  Future<void> initializePushNotifications() async {
    try {
      final messaging = FirebaseMessaging.instance;
      final settings = await messaging.requestPermission();
      add(NotificationStatusChanged(
        settings.authorizationStatus == AuthorizationStatus.authorized ||
                settings.authorizationStatus == AuthorizationStatus.provisional
            ? AuthorizationStatus.authorized
            : AuthorizationStatus.denied,
      ));

      final token = await messaging.getToken();
      if (token != null) await _registerToken(token);

      // Refresh token (e.g. after reinstall)
      messaging.onTokenRefresh.listen(_registerToken);

      // Show local notification when app is in foreground
      FirebaseMessaging.onMessage.listen((RemoteMessage message) {
        final n = message.notification;
        if (n != null) {
          showLocalNotification(
            id: message.hashCode,
            title: n.title,
            body: n.body,
            data: jsonEncode(message.data),
          );
        }
      });
    } catch (e) {
      log('NotificationBloc.initializePushNotifications error: $e');
    }
  }

  Future<void> _registerToken(String token) async {
    try {
      final prefs = await SharedPreferences.getInstance();
      final jwt = prefs.getString('token');
      if (jwt == null) return;
      await http.patch(
        Uri.parse('$API_BASE_URL/users/me/fcm-token'),
        headers: {
          'Content-Type': 'application/json',
          'Authorization': 'Bearer $jwt',
        },
        body: jsonEncode({'token': token}),
      );
      log('FCM token registered');
    } catch (e) {
      log('NotificationBloc._registerToken error: $e');
    }
  }

  void requestPermission() async {
    try {
      await requestLocalNotificationPermission();
    } catch (e) {
      log('NotificationBloc.requestPermission error: $e');
    }
  }
}