import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';

import '../../../../api/errors/error_mapper.dart';
import '../../../../api/marianumconnect/queries/push_device_test/push_device_test.dart';
import '../../../../push/push_registration.dart';
import '../../../../push/push_registration_store.dart';
import '../../../../routing/app_routes.dart';
import '../../../../state/app/modules/settings/bloc/settings_cubit.dart';
import '../../../../utils/haptics.dart';
import '../../../../widget/centered_leading.dart';

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

  @override
  Widget build(BuildContext context) {
    final settings = context.watch<SettingsCubit>();
    final talkSettings = settings.val().talkSettings;
    final notificationSettings = settings.val().notificationSettings;
    return Column(
      children: [
        ListTile(
          leading: const Icon(Icons.star_border),
          title: const Text('Favoriten im Talk nach oben sortieren'),
          trailing: Checkbox(
            value: talkSettings.sortFavoritesToTop,
            onChanged: (e) {
              Haptics.selection();
              settings.val(write: true).talkSettings.sortFavoritesToTop = e!;
            },
          ),
        ),
        ListTile(
          leading: const Icon(Icons.mark_email_unread_outlined),
          title: const Text('Ungelesene Chats nach oben sortieren'),
          trailing: Checkbox(
            value: talkSettings.sortUnreadToTop,
            onChanged: (e) {
              Haptics.selection();
              settings.val(write: true).talkSettings.sortUnreadToTop = e!;
            },
          ),
        ),
        ListTile(
          leading: const Icon(Icons.wallpaper_outlined),
          title: const Text('Chat-Hintergrund'),
          subtitle: const Text('Bild, Farbe und Darstellung anpassen'),
          trailing: const Icon(Icons.arrow_right),
          onTap: () => AppRoutes.openChatBackgroundSettings(context),
        ),
        ListTile(
          leading: const CenteredLeading(
            Icon(Icons.notifications_active_outlined),
          ),
          title: const Text('Push-Benachrichtigungen'),
          subtitle: const Text('Neue Talk-Nachrichten direkt aufs Gerät'),
          trailing: Checkbox(
            value: notificationSettings.enabled,
            onChanged: (e) {
              Haptics.selection();
              final enabled = e ?? false;
              settings.val(write: true).notificationSettings.enabled = enabled;
              if (enabled) {
                final messenger = ScaffoldMessenger.of(context);
                unawaited(() async {
                  // Only register when the OS permission isn't explicitly
                  // denied — otherwise NC + proxy would push into the void.
                  if (await PushRegistration.requestOsPermission()) {
                    await PushRegistration().register();
                  } else {
                    messenger.showSnackBar(
                      const SnackBar(
                        content: Text(
                          'Benachrichtigungen sind in den Systemeinstellungen '
                          'deaktiviert — bitte dort erlauben.',
                        ),
                      ),
                    );
                  }
                }());
              } else {
                unawaited(PushRegistration().unregister());
              }
            },
          ),
        ),
        if (notificationSettings.enabled) const _TestNotificationTile(),
      ],
    );
  }
}

/// "Send a test notification" action, shown only while push is enabled. The
/// button stays disabled until a registration is confirmed present, then calls
/// the backend and reports the result via a SnackBar.
class _TestNotificationTile extends StatefulWidget {
  const _TestNotificationTile();

  @override
  State<_TestNotificationTile> createState() => _TestNotificationTileState();
}

class _TestNotificationTileState extends State<_TestNotificationTile> {
  static const _permissionDeniedHint =
      'Benachrichtigungen sind in den Systemeinstellungen deaktiviert';

  bool _registered = false;
  bool _permissionDenied = false;
  bool _sending = false;

  @override
  void initState() {
    super.initState();
    _loadState();
  }

  Future<void> _loadState() async {
    final registered = await const PushRegistrationStore().isRegistered();
    final denied = await PushRegistration.isOsPermissionDenied();
    if (!mounted) return;
    setState(() {
      _registered = registered;
      _permissionDenied = denied;
    });
  }

  Future<void> _sendTest() async {
    if (_sending) return;
    Haptics.selection();
    final messenger = ScaffoldMessenger.of(context);
    // Re-check right before sending: the user may have flipped the OS
    // permission in the system settings since this tile was built.
    final denied = await PushRegistration.isOsPermissionDenied();
    if (!mounted) return;
    if (denied) {
      setState(() => _permissionDenied = true);
      messenger.showSnackBar(
        const SnackBar(
          content: Text('$_permissionDeniedHint — bitte dort erlauben.'),
        ),
      );
      return;
    }
    setState(() {
      _permissionDenied = false;
      _sending = true;
    });
    String message;
    try {
      final devices = await PushDeviceTest().run();
      message = devices >= 1
          ? 'Testbenachrichtigung an $devices Gerät(e) gesendet'
          : 'Kein Gerät registriert — Push-Registrierung prüfen';
    } on Object catch (e) {
      message = errorToUserMessage(e);
    }
    if (!mounted) return;
    setState(() => _sending = false);
    messenger.showSnackBar(SnackBar(content: Text(message)));
  }

  @override
  Widget build(BuildContext context) {
    if (!_registered) return const SizedBox.shrink();
    return ListTile(
      leading: const CenteredLeading(Icon(Icons.send_outlined)),
      title: const Text('Testbenachrichtigung senden'),
      subtitle: _permissionDenied
          ? Text(
              _permissionDeniedHint,
              style: TextStyle(color: Theme.of(context).colorScheme.error),
            )
          : const Text('Prüft, ob Push auf diesem Gerät ankommt'),
      trailing: _sending
          ? const SizedBox(
              width: 20,
              height: 20,
              child: CircularProgressIndicator(strokeWidth: 2),
            )
          : const Icon(Icons.arrow_right),
      enabled: !_sending,
      onTap: _sending ? null : _sendTest,
    );
  }
}