import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:provider/provider.dart';
import 'package:app_links/app_links.dart';
import 'package:hive_flutter/hive_flutter.dart';
// google_mobile_ads removed — switched to Adsterra only
import 'services/session_manager.dart';
import 'services/settings_service.dart';
import 'services/screen_time_service.dart';
import 'services/focusgram_router.dart';
import 'services/injection_controller.dart';
import 'services/credit_store.dart';
import 'services/bait_engine.dart';
import 'services/app_lock_service.dart';
import 'services/level_service.dart';
import 'services/snapshot_service.dart';
import 'screens/app_lock_screen.dart';
import 'screens/onboarding_page.dart';
import 'screens/main_webview_page.dart';
import 'screens/breath_gate_screen.dart';
import 'screens/app_session_picker.dart';
import 'screens/cooldown_gate_screen.dart';
import 'services/notification_service.dart';
import 'features/update_checker/update_checker_service.dart';
import 'features/preloader/instagram_preloader.dart';
import 'widgets/remote_popup_handler.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  // Lock to portrait
  await SystemChrome.setPreferredOrientations([
    DeviceOrientation.portraitUp,
    DeviceOrientation.portraitDown,
  ]);

  // ── Initialise storage & SDKs ──────────────────────────────
  await Hive.initFlutter();
  final creditStore = CreditStore();
  final baitEngine = BaitEngine();
  final levelService = LevelService();
  final appLockService = AppLockService();
  final snapshotService = SnapshotService();

  final sessionManager = SessionManager();
  final settingsService = SettingsService();
  final screenTimeService = ScreenTimeService();

  final updateChecker = UpdateCheckerService();

  await creditStore.init();
  await baitEngine.init();
  await appLockService.init();
  await levelService.init();
  await snapshotService.init();
  await sessionManager.init();
  await settingsService.init();
  await screenTimeService.init();
  await NotificationService().init(requestPermissions: true);
  runApp(
    MultiProvider(
      providers: [
        ChangeNotifierProvider.value(value: sessionManager),
        ChangeNotifierProvider.value(value: settingsService),
        ChangeNotifierProvider.value(value: screenTimeService),
        ChangeNotifierProvider.value(value: creditStore),
        ChangeNotifierProvider.value(value: baitEngine),
        ChangeNotifierProvider.value(value: levelService),
        ChangeNotifierProvider.value(value: appLockService),
        ChangeNotifierProvider.value(value: snapshotService),
        ChangeNotifierProvider.value(value: updateChecker),
      ],
      child: const FocusGramApp(),
    ),
  );

  // Fire and forget — preloads Instagram while app UI initialises.
  unawaited(InstagramPreloader.start(InjectionController.iOSUserAgent));
}

class FocusGramApp extends StatelessWidget {
  const FocusGramApp({super.key});

  @override
  Widget build(BuildContext context) {
    final settings = context.watch<SettingsService>();
    final isDark = settings.isDarkMode;

    return MaterialApp(
      title: 'FocusGram',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        brightness: isDark ? Brightness.dark : Brightness.light,
        colorScheme: isDark
            ? ColorScheme.dark(
                primary: Colors.blue.shade400,
                surface: Colors.black,
              )
            : ColorScheme.light(primary: Colors.blue),
        scaffoldBackgroundColor: isDark ? Colors.black : Colors.white,
        useMaterial3: true,
        splashColor: Colors.transparent,
        highlightColor: Colors.transparent,
      ),
      home: const InitialRouteHandler(),
    );
  }
}

/// Flow on every cold open:
///   1. Onboarding (if first run)
///   2. Cooldown Gate (if app-open cooldown active)
///   3. Breath Gate (if enabled in settings)
///   4. If an app session is already active, resume it
///   otherwise show App Session Picker
///   5. Main WebView
class InitialRouteHandler extends StatefulWidget {
  const InitialRouteHandler({super.key});

  @override
  State<InitialRouteHandler> createState() => _InitialRouteHandlerState();
}

class _InitialRouteHandlerState extends State<InitialRouteHandler>
    with WidgetsBindingObserver {
  bool _breathCompleted = false;
  bool _appSessionStarted = false;
  bool _onboardingCompleted = false;
  bool _lockScreenDismissed = false;
  late AppLinks _appLinks;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    _appLinks = AppLinks();
    _initDeepLinks();

    WidgetsBinding.instance.addPostFrameCallback((_) {
      RemotePopupHandler.checkAndShow(context);
    });
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    super.dispose();
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    final appLock = context.read<AppLockService>();
    if (state == AppLifecycleState.paused ||
        state == AppLifecycleState.inactive) {
      appLock.onBackgrounded();
    } else if (state == AppLifecycleState.resumed) {
      if (appLock.shouldLockOnResume) {
        appLock.onLockScreenShown();
        _showLockScreen();
      }
    }
  }

  Future<void> _showLockScreen() async {
    final result = await Navigator.push<bool>(
      context,
      MaterialPageRoute(builder: (_) => const AppLockScreen(forAppWide: true)),
    );
    if (result == true && mounted) {
      setState(() => _lockScreenDismissed = true);
    }
  }

  Future<void> _initDeepLinks() async {
    // 1. Handle background links while app is running
    _appLinks.uriLinkStream.listen((uri) {
      // debugPrint('Incoming Deep Link: $uri');
      FocusGramRouter.pendingUrl.value = uri.toString();
    });

    // 2. Handle the initial link that opened the app
    final initialUri = await _appLinks.getInitialLink();
    if (initialUri != null) {
      // debugPrint('Initial Deep Link: $initialUri');
      FocusGramRouter.pendingUrl.value = initialUri.toString();
    }
  }

  @override
  Widget build(BuildContext context) {
    final sm = context.watch<SessionManager>();
    final settings = context.watch<SettingsService>();
    final appLock = context.watch<AppLockService>();

    // Step 0: App-wide lock (shows before everything, once per cold start)
    if (appLock.needsUnlockOnStart && !_lockScreenDismissed) {
      WidgetsBinding.instance.addPostFrameCallback((_) {
        if (!appLock.isShowingLock) {
          appLock.onLockScreenShown();
          _showLockScreen();
        }
      });
    }

    // Step 1: Onboarding
    if (settings.isFirstRun && !_onboardingCompleted) {
      return OnboardingPage(
        onFinish: () => setState(() => _onboardingCompleted = true),
      );
    }

    // Step 2: Cooldown gate — if too soon since last session
    if (sm.isAppOpenCooldownActive) {
      return const CooldownGateScreen();
    }

    // Step 3: Breath gate
    if (settings.showBreathGate && !_breathCompleted) {
      return BreathGateScreen(
        durationSeconds: settings.breathGateSeconds,
        onFinish: () => setState(() => _breathCompleted = true),
      );
    }

    // Step 4: App session picker / resume existing session
    if (!_appSessionStarted) {
      if (sm.isAppSessionActive) {
        // User already has an active app session — don't ask intention again.
        _appSessionStarted = true;
      } else {
        return AppSessionPickerScreen(
          onSessionStarted: () => setState(() => _appSessionStarted = true),
        );
      }
    }

    // Step 5: Main app
    return const MainWebViewPage();
  }
}