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

import '../../core/export/export_service.dart';
import '../../core/notifications/notification_service.dart';
import '../../core/providers/biometric_provider.dart';
import '../../core/providers/database_provider.dart';
import '../../core/providers/settings_provider.dart';

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

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final reminderEnabled =
        ref.watch(settingProvider(SettingsKeys.reminderEnabled));
    final reminderTimeStr =
        ref.watch(settingProvider(SettingsKeys.reminderTime));
    final biometricEnabled =
        ref.watch(settingProvider(SettingsKeys.biometricEnabled));
    final themeVal = ref.watch(settingProvider(SettingsKeys.themMode));
    final biometricAvailable = ref.watch(biometricAvailableProvider);
    final notifier = ref.read(settingsNotifierProvider.notifier);

    final isReminderOn = reminderEnabled.value == 'true';
    final currentTheme = themeVal.value ?? 'system';
    final isBiometricOn = biometricEnabled.value == 'true';
    final reminderTime =
        _parseTime(reminderTimeStr.value) ?? const TimeOfDay(hour: 20, minute: 0);

    return Scaffold(
      appBar: AppBar(title: const Text('Settings')),
      body: ListView(
        children: [
          _section(context, 'Appearance'),
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
            child: SegmentedButton<String>(
              segments: const [
                ButtonSegment(
                    value: 'system',
                    label: Text('System'),
                    icon: Icon(Icons.brightness_auto)),
                ButtonSegment(
                    value: 'light',
                    label: Text('Light'),
                    icon: Icon(Icons.light_mode)),
                ButtonSegment(
                    value: 'dark',
                    label: Text('Dark'),
                    icon: Icon(Icons.dark_mode)),
              ],
              selected: {currentTheme},
              onSelectionChanged: (s) => notifier.setThemeMode(s.first),
            ),
          ),
          _section(context, 'Reminders'),
          SwitchListTile(
            title: const Text('Daily reminder'),
            subtitle: const Text('Get prompted to log your mood'),
            value: isReminderOn,
            onChanged: (v) =>
                _toggleReminder(context, ref, v, reminderTime, notifier),
          ),
          if (isReminderOn)
            ListTile(
              leading: const Icon(Icons.schedule),
              title: const Text('Reminder time'),
              trailing: Text(
                reminderTime.format(context),
                style: Theme.of(context).textTheme.bodyLarge,
              ),
              onTap: () => _pickTime(context, reminderTime, notifier),
            ),
          if (biometricAvailable.value == true) ...[
            _section(context, 'Privacy'),
            SwitchListTile(
              title: const Text('Biometric lock'),
              subtitle:
                  const Text('Require fingerprint or face unlock to open'),
              value: isBiometricOn,
              onChanged: (v) => notifier.setBiometricEnabled(v),
            ),
          ],
          _section(context, 'Data'),
          ListTile(
            leading: const Icon(Icons.picture_as_pdf_outlined),
            title: const Text('Export to PDF'),
            subtitle: const Text('Share your complete mood history'),
            onTap: () => _export(context, ref),
          ),
          const Divider(),
          const ListTile(
            title: Text('DailyYou'),
            subtitle: Text('Version 1.0.0'),
          ),
        ],
      ),
    );
  }

  Widget _section(BuildContext context, String title) => Padding(
        padding: const EdgeInsets.fromLTRB(16, 16, 16, 4),
        child: Text(
          title,
          style: Theme.of(context).textTheme.labelLarge?.copyWith(
                color: Theme.of(context).colorScheme.primary,
              ),
        ),
      );

  TimeOfDay? _parseTime(String? val) {
    if (val == null) return null;
    final parts = val.split(':');
    if (parts.length != 2) return null;
    final h = int.tryParse(parts[0]);
    final m = int.tryParse(parts[1]);
    if (h == null || m == null) return null;
    return TimeOfDay(hour: h, minute: m);
  }

  Future<void> _toggleReminder(
    BuildContext context,
    WidgetRef ref,
    bool enable,
    TimeOfDay time,
    SettingsNotifier notifier,
  ) async {
    if (enable) {
      final granted = await NotificationService.requestPermission();
      if (!context.mounted) return;
      if (!granted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
              content:
                  Text('Notification permission required to set reminders')),
        );
        return;
      }
      await NotificationService.scheduleDaily(time);
    } else {
      await NotificationService.cancelAll();
    }
    await notifier.setReminderEnabled(enable);
  }

  Future<void> _pickTime(
    BuildContext context,
    TimeOfDay current,
    SettingsNotifier notifier,
  ) async {
    final picked =
        await showTimePicker(context: context, initialTime: current);
    if (!context.mounted || picked == null) return;
    await notifier.setReminderTime(picked.hour, picked.minute);
    await NotificationService.scheduleDaily(picked);
  }

  Future<void> _export(BuildContext context, WidgetRef ref) async {
    try {
      final entries = await ref.read(moodDaoProvider).getAllEntries();
      await ExportService.exportToPdf(entries);
    } catch (e) {
      if (!context.mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Export failed: $e')),
      );
    }
  }
}