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

import 'package:household_keeper/core/notifications/notification_service.dart';
import 'package:household_keeper/core/notifications/notification_settings_notifier.dart';
import 'package:household_keeper/core/providers/database_provider.dart';
import 'package:household_keeper/core/theme/theme_provider.dart';
import 'package:household_keeper/features/home/data/daily_plan_dao.dart';
import 'package:household_keeper/l10n/app_localizations.dart';

class SettingsScreen extends ConsumerStatefulWidget {
  const SettingsScreen({super.key});

  @override
  ConsumerState<SettingsScreen> createState() => _SettingsScreenState();
}

class _SettingsScreenState extends ConsumerState<SettingsScreen> {
  Future<void> _onNotificationToggle(bool value) async {
    if (value) {
      // Enabling: request permission first
      final granted = await NotificationService().requestPermission();
      if (!granted) {
        // Permission denied — show SnackBar to guide user to system settings
        if (!mounted) return;
        final l10n = AppLocalizations.of(context);
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(l10n.notificationsPermissionDeniedHint),
          ),
        );
        // Toggle stays OFF — do not update state
        return;
      }
      // Permission granted: enable and schedule
      await ref
          .read(notificationSettingsProvider.notifier)
          .setEnabled(true);
      await _scheduleNotification();
    } else {
      // Disabling: update state and cancel
      await ref
          .read(notificationSettingsProvider.notifier)
          .setEnabled(false);
      await NotificationService().cancelAll();
    }
  }

  Future<void> _scheduleNotification() async {
    final settings = ref.read(notificationSettingsProvider);
    if (!settings.enabled) return;

    final db = ref.read(appDatabaseProvider);
    final dao = DailyPlanDao(db);
    final total = await dao.getOverdueAndTodayTaskCount();
    final overdue = await dao.getOverdueTaskCount();

    if (total == 0) {
      // No tasks today — skip notification
      await NotificationService().cancelAll();
      return;
    }

    if (!mounted) return;
    final l10n = AppLocalizations.of(context);
    final body = overdue > 0
        ? l10n.notificationBodyWithOverdue(total, overdue)
        : l10n.notificationBody(total);
    final title = l10n.notificationTitle;

    await NotificationService().scheduleDailyNotification(
      time: settings.time,
      title: title,
      body: body,
    );
  }

  Future<void> _onPickTime() async {
    final settings = ref.read(notificationSettingsProvider);
    final picked = await showTimePicker(
      context: context,
      initialTime: settings.time,
      initialEntryMode: TimePickerEntryMode.dial,
    );
    if (picked != null) {
      await ref
          .read(notificationSettingsProvider.notifier)
          .setTime(picked);
      await _scheduleNotification();
    }
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final theme = Theme.of(context);
    final currentThemeMode = ref.watch(themeProvider);
    final notificationSettings = ref.watch(notificationSettingsProvider);

    return ListView(
      children: [
        // Section 1: Appearance (Darstellung)
        Padding(
          padding: const EdgeInsets.fromLTRB(16, 24, 16, 8),
          child: Text(
            l10n.settingsSectionAppearance,
            style: theme.textTheme.titleMedium?.copyWith(
              color: theme.colorScheme.primary,
            ),
          ),
        ),
        ListTile(
          title: Text(l10n.settingsThemeLabel),
          subtitle: Padding(
            padding: const EdgeInsets.only(top: 8),
            child: SegmentedButton<ThemeMode>(
              segments: [
                ButtonSegment<ThemeMode>(
                  value: ThemeMode.system,
                  label: Text(l10n.themeSystem),
                  icon: const Icon(Icons.settings_suggest_outlined),
                ),
                ButtonSegment<ThemeMode>(
                  value: ThemeMode.light,
                  label: Text(l10n.themeLight),
                  icon: const Icon(Icons.light_mode_outlined),
                ),
                ButtonSegment<ThemeMode>(
                  value: ThemeMode.dark,
                  label: Text(l10n.themeDark),
                  icon: const Icon(Icons.dark_mode_outlined),
                ),
              ],
              selected: {currentThemeMode},
              onSelectionChanged: (selection) {
                ref
                    .read(themeProvider.notifier)
                    .setThemeMode(selection.first);
              },
            ),
          ),
        ),

        const Divider(indent: 16, endIndent: 16, height: 32),

        // Section 2: Notifications (Benachrichtigungen)
        Padding(
          padding: const EdgeInsets.fromLTRB(16, 8, 16, 8),
          child: Text(
            l10n.settingsSectionNotifications,
            style: theme.textTheme.titleMedium?.copyWith(
              color: theme.colorScheme.primary,
            ),
          ),
        ),
        SwitchListTile(
          title: Text(l10n.notificationsEnabledLabel),
          value: notificationSettings.enabled,
          onChanged: _onNotificationToggle,
        ),
        // Progressive disclosure: time picker only when enabled
        AnimatedSize(
          duration: const Duration(milliseconds: 200),
          child: notificationSettings.enabled
              ? ListTile(
                  title: Text(l10n.notificationsTimeLabel),
                  trailing: Text(notificationSettings.time.format(context)),
                  onTap: _onPickTime,
                )
              : const SizedBox.shrink(),
        ),

        const Divider(indent: 16, endIndent: 16, height: 32),

        // Section 3: About (Ueber)
        Padding(
          padding: const EdgeInsets.fromLTRB(16, 8, 16, 8),
          child: Text(
            l10n.settingsSectionAbout,
            style: theme.textTheme.titleMedium?.copyWith(
              color: theme.colorScheme.primary,
            ),
          ),
        ),
        ListTile(
          title: Text(l10n.aboutAppName),
          subtitle: Text(l10n.aboutTagline),
        ),
        ListTile(
          title: const Text('Version'),
          subtitle: Text(l10n.aboutVersion('0.1.0')),
        ),
      ],
    );
  }
}