Firebase Analytics والأحداث المخصصة

# pubspec.yaml
dependencies:
  flutter:
    sdk: flutter
  firebase_core: ^3.6.0
  firebase_analytics: ^11.3.3

import 'package:firebase_analytics/firebase_analytics.dart';
import 'package:firebase_core/firebase_core.dart';
import 'firebase_options.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp(
    options: DefaultFirebaseOptions.currentPlatform,
  );

  // الحصول على المثيل الفريد
  final analytics = FirebaseAnalytics.instance;

  // إرفاق المراقب لإطلاق أحداث screen_view تلقائياً
  runApp(MyApp(analytics: analytics));
}

class MyApp extends StatelessWidget {
  final FirebaseAnalytics analytics;
  const MyApp({super.key, required this.analytics});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Analytics Demo',
      navigatorObservers: [
        FirebaseAnalyticsObserver(analytics: analytics),
      ],
      home: const HomeScreen(),
    );
  }
}

class AnalyticsService {
  final FirebaseAnalytics _analytics = FirebaseAnalytics.instance;

  // --- دوال الأحداث المعرّفة مسبقاً ---

  Future<void> logLogin({required String method}) =>
      _analytics.logLogin(loginMethod: method);

  Future<void> logSignUp({required String method}) =>
      _analytics.logSignUp(signUpMethod: method);

  Future<void> logSearch({required String term}) =>
      _analytics.logSearch(searchTerm: term);

  Future<void> logShare({
    required String contentType,
    required String itemId,
    required String method,
  }) =>
      _analytics.logShare(
        contentType: contentType,
        itemId: itemId,
        method: method,
      );

  // --- حدث مخصص ---

  Future<void> logCourseEnrolled({
    required String courseId,
    required String courseName,
    required String level,
  }) =>
      _analytics.logEvent(
        name: 'course_enrolled',          // snake_case، بحد أقصى 40 محرفاً
        parameters: <String, Object>{
          'course_id': courseId,           // نص (بحد أقصى 100 محرف)
          'course_name': courseName,
          'level': level,
          'timestamp': DateTime.now().millisecondsSinceEpoch,
        },
      );

  Future<void> logLessonCompleted({
    required String lessonId,
    required int durationSeconds,
    required int score,
  }) =>
      _analytics.logEvent(
        name: 'lesson_completed',
        parameters: <String, Object>{
          'lesson_id': lessonId,
          'duration_seconds': durationSeconds,  // int أو double
          'score': score,
          'passed': score >= 70,               // bool يُحوَّل إلى int (1/0)
        },
      );
}

Future<void> setUserProperties({
  required String userId,
  required String plan,
  required String preferredLanguage,
}) async {
  final analytics = FirebaseAnalytics.instance;

  // ربط الأحداث بمعرّف مستخدم داخلي (مجزّأ — لا يحتوي على معلومات تعريف شخصية)
  await analytics.setUserId(id: userId);

  // خصائص مستخدم مخصصة (بحد أقصى 25 لكل مشروع، اسم 24 محرفاً، قيمة 36 محرفاً)
  await analytics.setUserProperty(name: 'subscription_plan', value: plan);
  await analytics.setUserProperty(
    name: 'preferred_language',
    value: preferredLanguage,
  );
}