rely/lib/features/ai_digest/application/ai_digest_notifier.dart

import 'dart:async';

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

const String aiDigestNotificationPayload = 'ai_digest_review_inbox';

final Provider<AiDigestNotificationIntentBus>
aiDigestNotificationIntentBusProvider = Provider<AiDigestNotificationIntentBus>(
  (Ref ref) {
    final AiDigestNotificationIntentBus bus = AiDigestNotificationIntentBus();
    ref.onDispose(() {
      unawaited(bus.close());
    });
    return bus;
  },
);

class AiDigestNotificationIntentBus {
  final StreamController<String> _controller =
      StreamController<String>.broadcast();

  Stream<String> get intents => _controller.stream;

  void emitTap(String payload) {
    if (!_controller.isClosed) {
      _controller.add(payload);
    }
  }

  Future<void> close() => _controller.close();
}

abstract interface class AiDigestNotifier {
  Future<void> showDigestReady(int count);
}

class LocalAiDigestNotifier implements AiDigestNotifier {
  LocalAiDigestNotifier({
    FlutterLocalNotificationsPlugin? plugin,
    void Function(String payload)? onTapPayload,
  }) : _plugin = plugin ?? FlutterLocalNotificationsPlugin(),
       _onTapPayload = onTapPayload;

  final FlutterLocalNotificationsPlugin _plugin;
  final void Function(String payload)? _onTapPayload;
  Future<void>? _initializeFuture;

  @override
  Future<void> showDigestReady(int count) async {
    if (!_supportsNotifications()) {
      return;
    }
    await _ensureInitialized();
    await _plugin.show(
      id: 8124,
      title: 'Relationship digest ready',
      body:
          '$count private ${count == 1 ? 'suggestion is' : 'suggestions are'} ready to review.',
      notificationDetails: const NotificationDetails(
        android: AndroidNotificationDetails(
          'relationship_saver_ai_digest',
          'Relationship Digest',
          channelDescription: 'Private AI digest suggestions ready for review',
          importance: Importance.defaultImportance,
          priority: Priority.defaultPriority,
        ),
        iOS: DarwinNotificationDetails(),
        macOS: DarwinNotificationDetails(),
      ),
      payload: aiDigestNotificationPayload,
    );
  }

  Future<void> _ensureInitialized() {
    return _initializeFuture ??= _plugin.initialize(
      settings: const InitializationSettings(
        android: AndroidInitializationSettings('@mipmap/ic_launcher'),
        iOS: DarwinInitializationSettings(),
        macOS: DarwinInitializationSettings(),
      ),
      onDidReceiveNotificationResponse: (NotificationResponse response) {
        final String? payload = response.payload;
        if (payload != null && payload.isNotEmpty) {
          _onTapPayload?.call(payload);
        }
      },
    );
  }

  bool _supportsNotifications() {
    if (kIsWeb) {
      return false;
    }
    return defaultTargetPlatform != TargetPlatform.linux;
  }
}

final Provider<AiDigestNotifier> aiDigestNotifierProvider =
    Provider<AiDigestNotifier>((Ref ref) {
      return LocalAiDigestNotifier(
        onTapPayload: ref.watch(aiDigestNotificationIntentBusProvider).emitTap,
      );
    });