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

import '../app/build_info.dart';
import '../app/error_message.dart';
import '../app/load_state.dart';
import '../features/settings/models/app_theme_preset.dart';
import '../features/settings/models/geofence_system_state.dart';
import '../features/settings/providers/settings_providers.dart';
import '../models/home_config.dart';
import '../providers/providers.dart';
import 'home_edit_screen.dart';
import 'homes_screen.dart';

enum SettingsEntryPoint { homes, remote }

class SettingsScreen extends ConsumerStatefulWidget {
  final SettingsEntryPoint entryPoint;

  const SettingsScreen({super.key, required this.entryPoint});

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

class _SettingsScreenState extends ConsumerState<SettingsScreen>
    with WidgetsBindingObserver {
  bool _savingGeofence = false;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
  }

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

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (state == AppLifecycleState.resumed) {
      ref.invalidate(geofenceSystemStatusProvider);
    }
  }

  @override
  Widget build(BuildContext context) {
    final currentHome = ref.watch(currentHomeProvider);
    final authState = ref.watch(authInfoProvider);
    final themePreset = ref.watch(appThemeProvider);
    final geofenceStatus = ref.watch(geofenceSystemStatusProvider);
    final geofenceState = geofenceStatus.asData?.value;

    return Scaffold(
      appBar: AppBar(title: const Text('НАСТРОЙКИ')),
      body: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          _SectionTitle(
            title: 'Дом и подключение',
            subtitle: 'К какому backend сейчас привязано приложение',
          ),
          _SectionCard(
            children: [
              if (currentHome == null)
                const _EmptySectionState(
                  icon: Icons.home_outlined,
                  title: 'Активный дом не выбран',
                  message: 'Выберите или добавьте дом, чтобы управлять светом.',
                )
              else ...[
                _InfoRow(label: 'Дом', value: currentHome.name),
                _InfoRow(label: 'Backend', value: currentHome.url),
                _InfoRow(
                  label: 'Доступ',
                  value: _authSummary(authState),
                  muted: authState.status == LoadStatus.idle,
                ),
                const SizedBox(height: 12),
                Wrap(
                  spacing: 8,
                  runSpacing: 8,
                  children: [
                    FilledButton.tonalIcon(
                      onPressed: () => _openHomeEditor(context, currentHome),
                      icon: const Icon(Icons.edit_location_alt_outlined),
                      label: const Text('Редактировать дом'),
                    ),
                    OutlinedButton.icon(
                      onPressed: () => _openHomes(context),
                      icon: const Icon(Icons.home_work_outlined),
                      label: const Text('Дома'),
                    ),
                  ],
                ),
              ],
            ],
          ),
          const SizedBox(height: 20),
          _SectionTitle(
            title: 'Гео-автоматизация',
            subtitle: 'Автовыключение света при уходе из дома',
          ),
          _SectionCard(
            children: [
              if (currentHome == null)
                const _EmptySectionState(
                  icon: Icons.location_off_outlined,
                  title: 'Сначала нужен активный дом',
                  message: 'Без выбранного дома geofence настраивать нечего.',
                )
              else ...[
                SwitchListTile(
                  contentPadding: EdgeInsets.zero,
                  secondary: Icon(
                    Icons.directions_walk,
                    color: currentHome.hasCoordinates
                        ? Theme.of(context).colorScheme.primary
                        : Theme.of(context).disabledColor,
                  ),
                  title: const Text('Выключать свет при уходе'),
                  subtitle: Text(
                    currentHome.hasCoordinates
                        ? 'Работает только для текущего активного дома'
                        : 'Сначала задайте координаты дома',
                  ),
                  value: currentHome.geofenceEnabled,
                  onChanged: currentHome.hasCoordinates && !_savingGeofence
                      ? (enabled) => _setGeofenceEnabled(currentHome, enabled)
                      : null,
                ),
                const Divider(height: 24),
                _StatusTile(
                  icon: _statusIcon(geofenceState, currentHome),
                  color: _statusColor(context, geofenceState, currentHome),
                  title: _statusTitle(geofenceState, currentHome),
                  subtitle: _statusSubtitle(geofenceState, currentHome),
                ),
                if (_savingGeofence)
                  const Padding(
                    padding: EdgeInsets.only(top: 12),
                    child: LinearProgressIndicator(minHeight: 3),
                  ),
                const SizedBox(height: 12),
                ListTile(
                  contentPadding: EdgeInsets.zero,
                  leading: const Icon(Icons.radar_outlined),
                  title: const Text('Радиус срабатывания'),
                  subtitle: Text('${currentHome.geofenceRadiusMeters} м'),
                  trailing: const Icon(Icons.chevron_right),
                  enabled: currentHome.hasCoordinates && !_savingGeofence,
                  onTap: currentHome.hasCoordinates && !_savingGeofence
                      ? () => _editGeofenceRadius(context, currentHome)
                      : null,
                ),
                const SizedBox(height: 8),
                Wrap(
                  spacing: 8,
                  runSpacing: 8,
                  children: _buildGeofenceActions(
                    context: context,
                    home: currentHome,
                    systemState: geofenceState,
                  ),
                ),
              ],
            ],
          ),
          const SizedBox(height: 20),
          _SectionTitle(
            title: 'Внешний вид',
            subtitle: 'Фиксированные темы без лишней кастомизации',
          ),
          _SectionCard(
            children: [
              RadioGroup<AppThemePreset>(
                groupValue: themePreset,
                onChanged: (value) {
                  if (value != null) {
                    ref.read(appThemeProvider.notifier).setTheme(value);
                  }
                },
                child: Column(
                  children: [
                    for (final preset in AppThemePreset.values)
                      RadioListTile<AppThemePreset>(
                        value: preset,
                        activeColor: preset.accentColor,
                        secondary: CircleAvatar(
                          radius: 12,
                          backgroundColor: preset.accentColor,
                        ),
                        title: Text(preset.title),
                        subtitle: Text(preset.subtitle),
                      ),
                  ],
                ),
              ),
            ],
          ),
          const SizedBox(height: 20),
          _SectionTitle(
            title: 'О приложении',
            subtitle: 'Короткая техническая сводка без маркетинговой воды',
          ),
          _SectionCard(
            children: [
              const _InfoRow(label: 'Приложение', value: 'Ignis App'),
              _InfoRow(label: 'Сборка', value: BuildInfo.label),
              _InfoRow(label: 'Тема', value: themePreset.title),
              _InfoRow(
                label: 'Backend',
                value: currentHome?.url ?? 'не выбран',
                muted: currentHome == null,
              ),
              const SizedBox(height: 12),
              FilledButton.tonalIcon(
                onPressed: () => _copyDiagnosticsSummary(
                  currentHome,
                  authState,
                  themePreset,
                ),
                icon: const Icon(Icons.content_copy_outlined),
                label: const Text('Скопировать сводку'),
              ),
            ],
          ),
        ],
      ),
    );
  }

  List<Widget> _buildGeofenceActions({
    required BuildContext context,
    required HomeConfig home,
    required GeofenceSystemState? systemState,
  }) {
    final locationNotifier = ref.read(userLocationProvider.notifier);
    final issue = systemState?.issue;

    if (!home.hasCoordinates) {
      return [
        FilledButton.tonalIcon(
          onPressed: () => _openHomeEditor(context, home),
          icon: const Icon(Icons.place_outlined),
          label: const Text('Задать координаты'),
        ),
      ];
    }

    return switch (issue) {
      GeofenceSystemIssue.locationServicesDisabled => [
        FilledButton.tonalIcon(
          onPressed: () async {
            await locationNotifier.openLocationSettings();
            ref.invalidate(geofenceSystemStatusProvider);
          },
          icon: const Icon(Icons.location_searching_outlined),
          label: const Text('Включить геолокацию'),
        ),
      ],
      GeofenceSystemIssue.permissionDenied => [
        FilledButton.tonalIcon(
          onPressed: () async {
            await locationNotifier.requestPermission();
            ref.invalidate(geofenceSystemStatusProvider);
          },
          icon: const Icon(Icons.verified_user_outlined),
          label: const Text('Запросить доступ'),
        ),
      ],
      GeofenceSystemIssue.permissionDeniedForever ||
      GeofenceSystemIssue.backgroundPermissionRequired => [
        FilledButton.tonalIcon(
          onPressed: () async {
            await locationNotifier.openAppSettings();
            ref.invalidate(geofenceSystemStatusProvider);
          },
          icon: const Icon(Icons.settings_outlined),
          label: const Text('Открыть настройки Android'),
        ),
      ],
      _ => [
        OutlinedButton.icon(
          onPressed: () => _openHomeEditor(context, home),
          icon: const Icon(Icons.edit_outlined),
          label: const Text('Координаты дома'),
        ),
      ],
    };
  }

  Future<void> _setGeofenceEnabled(HomeConfig home, bool enabled) async {
    await _saveCurrentHome(
      home.copyWith(geofenceEnabled: enabled),
      successMessage: enabled
          ? 'Автовыключение включено'
          : 'Автовыключение выключено',
    );
  }

  Future<void> _saveCurrentHome(
    HomeConfig updatedHome, {
    String? successMessage,
  }) async {
    setState(() => _savingGeofence = true);
    try {
      await ref.read(homesProvider.notifier).update(updatedHome);
      await ref.read(currentHomeProvider.notifier).switchTo(updatedHome);
      ref.invalidate(geofenceSystemStatusProvider);
      if (mounted && successMessage != null) {
        ScaffoldMessenger.of(
          context,
        ).showSnackBar(SnackBar(content: Text(successMessage)));
      }
    } catch (error) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(
              'Не удалось сохранить настройки: ${describeLoadError(error)}',
            ),
          ),
        );
      }
    } finally {
      if (mounted) {
        setState(() => _savingGeofence = false);
      }
    }
  }

  Future<void> _editGeofenceRadius(
    BuildContext context,
    HomeConfig home,
  ) async {
    var draft = home.geofenceRadiusMeters.toDouble();
    final saved = await showModalBottomSheet<int>(
      context: context,
      showDragHandle: true,
      builder: (sheetContext) {
        return StatefulBuilder(
          builder: (context, setModalState) {
            final roundedDraft = (draft / 50).round() * 50;
            return SafeArea(
              top: false,
              child: Padding(
                padding: const EdgeInsets.fromLTRB(20, 8, 20, 20),
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    const Text(
                      'Радиус geofence',
                      style: TextStyle(
                        fontSize: 18,
                        fontWeight: FontWeight.w700,
                      ),
                    ),
                    const SizedBox(height: 8),
                    Text(
                      '$roundedDraft м',
                      style: Theme.of(context).textTheme.headlineSmall,
                    ),
                    const SizedBox(height: 8),
                    Slider(
                      value: draft.clamp(100, 5000),
                      min: 100,
                      max: 5000,
                      divisions: 98,
                      label: '$roundedDraft м',
                      onChanged: (value) {
                        setModalState(() => draft = value);
                      },
                    ),
                    const SizedBox(height: 4),
                    const Text(
                      'Чем больше радиус, тем меньше шанс ложного срабатывания далеко от дома.',
                    ),
                    const SizedBox(height: 16),
                    Row(
                      children: [
                        TextButton(
                          onPressed: () => Navigator.of(sheetContext).pop(),
                          child: const Text('Отмена'),
                        ),
                        const Spacer(),
                        FilledButton(
                          onPressed: () =>
                              Navigator.of(sheetContext).pop(roundedDraft),
                          child: const Text('Сохранить'),
                        ),
                      ],
                    ),
                  ],
                ),
              ),
            );
          },
        );
      },
    );

    if (saved == null || saved == home.geofenceRadiusMeters) {
      return;
    }

    await _saveCurrentHome(
      home.copyWith(geofenceRadiusMeters: saved),
      successMessage: 'Радиус geofence обновлён',
    );
  }

  Future<void> _copyDiagnosticsSummary(
    HomeConfig? currentHome,
    LoadState authState,
    AppThemePreset themePreset,
  ) async {
    final lines = [
      'app=Ignis App',
      'build=${BuildInfo.label}',
      'theme=${themePreset.storageValue}',
      'home=${currentHome?.name ?? 'none'}',
      'backend=${currentHome?.url ?? 'none'}',
      'auth=${_authSummary(authState)}',
      'geofence_enabled=${currentHome?.geofenceEnabled ?? false}',
      'geofence_radius=${currentHome?.geofenceRadiusMeters ?? 0}',
      'has_coordinates=${currentHome?.hasCoordinates == true}',
    ];
    await Clipboard.setData(ClipboardData(text: lines.join('\n')));
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      const SnackBar(content: Text('Сводка скопирована в буфер обмена')),
    );
  }

  String _authSummary(LoadState authState) {
    final auth = authState.data;
    if (auth == null) {
      if (authState.hasError) {
        return authState.errorMessage ?? 'ошибка проверки доступа';
      }
      return 'не загружено';
    }

    final role = auth.isAdmin ? 'admin' : 'guest';
    if (auth.name == null || auth.name!.trim().isEmpty) {
      return role;
    }
    return '${auth.name} · $role';
  }

  IconData _statusIcon(GeofenceSystemState? state, HomeConfig home) {
    if (!home.geofenceEnabled) {
      return Icons.pause_circle_outline;
    }

    return switch (state?.issue) {
      GeofenceSystemIssue.ready => Icons.verified_outlined,
      GeofenceSystemIssue.locationServicesDisabled => Icons.location_disabled,
      GeofenceSystemIssue.permissionDenied ||
      GeofenceSystemIssue.permissionDeniedForever ||
      GeofenceSystemIssue.backgroundPermissionRequired =>
        Icons.gpp_bad_outlined,
      GeofenceSystemIssue.missingCoordinates => Icons.place_outlined,
      _ => Icons.info_outline,
    };
  }

  Color _statusColor(
    BuildContext context,
    GeofenceSystemState? state,
    HomeConfig home,
  ) {
    if (!home.geofenceEnabled) {
      return Theme.of(context).colorScheme.secondary;
    }
    return switch (state?.issue) {
      GeofenceSystemIssue.ready => Colors.green,
      GeofenceSystemIssue.locationServicesDisabled ||
      GeofenceSystemIssue.permissionDenied ||
      GeofenceSystemIssue.permissionDeniedForever ||
      GeofenceSystemIssue.backgroundPermissionRequired ||
      GeofenceSystemIssue.missingCoordinates => Theme.of(
        context,
      ).colorScheme.error,
      _ => Theme.of(context).colorScheme.primary,
    };
  }

  String _statusTitle(GeofenceSystemState? state, HomeConfig home) {
    if (!home.geofenceEnabled) {
      return 'Автовыключение выключено';
    }

    return switch (state?.issue) {
      GeofenceSystemIssue.ready => 'Geofence готов',
      GeofenceSystemIssue.missingCoordinates => 'Нужны координаты дома',
      GeofenceSystemIssue.locationServicesDisabled => 'Геолокация выключена',
      GeofenceSystemIssue.permissionDenied => 'Нужен доступ к геолокации',
      GeofenceSystemIssue.permissionDeniedForever => 'Доступ запрещён навсегда',
      GeofenceSystemIssue.backgroundPermissionRequired =>
        'Нужен доступ «Всегда»',
      GeofenceSystemIssue.noActiveHome => 'Нет активного дома',
      null => 'Проверяем системные условия',
    };
  }

  String _statusSubtitle(GeofenceSystemState? state, HomeConfig home) {
    if (!home.geofenceEnabled) {
      return home.hasCoordinates
          ? 'Можно заранее настроить радиус и включить позже.'
          : 'Сначала задайте координаты дома, потом включайте geofence.';
    }

    return switch (state?.issue) {
      GeofenceSystemIssue.ready =>
        'Android сможет отслеживать выход из зоны и запускать автовыключение.',
      GeofenceSystemIssue.missingCoordinates =>
        'Без координат дома geofence физически некуда поставить.',
      GeofenceSystemIssue.locationServicesDisabled =>
        'Пока системная геолокация выключена, фоновое срабатывание не поднимется.',
      GeofenceSystemIssue.permissionDenied =>
        'Нужно хотя бы базовое разрешение на геолокацию.',
      GeofenceSystemIssue.permissionDeniedForever =>
        'Разрешение нужно вернуть вручную в настройках Android.',
      GeofenceSystemIssue.backgroundPermissionRequired =>
        'Для фонового geofence нужен доступ к геолокации в режиме «Всегда».',
      GeofenceSystemIssue.noActiveHome =>
        'Сначала выберите активный дом, для которого будет работать автоматика.',
      null => 'Собираем информацию о системных ограничениях.',
    };
  }

  Future<void> _openHomeEditor(BuildContext context, HomeConfig home) async {
    await Navigator.of(
      context,
    ).push(MaterialPageRoute(builder: (_) => HomeEditScreen(home: home)));
    await ref.read(homesProvider.notifier).load();
    await ref.read(currentHomeProvider.notifier).load();
    ref.invalidate(geofenceSystemStatusProvider);
  }

  Future<void> _openHomes(BuildContext context) async {
    if (widget.entryPoint == SettingsEntryPoint.homes) {
      Navigator.of(context).pop();
      return;
    }
    Navigator.of(
      context,
    ).pushReplacement(MaterialPageRoute(builder: (_) => const HomesScreen()));
  }
}

class _SectionTitle extends StatelessWidget {
  final String title;
  final String subtitle;

  const _SectionTitle({required this.title, required this.subtitle});

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 8),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(
            title,
            style: Theme.of(
              context,
            ).textTheme.titleMedium?.copyWith(fontWeight: FontWeight.w700),
          ),
          const SizedBox(height: 2),
          Text(
            subtitle,
            style: Theme.of(
              context,
            ).textTheme.bodySmall?.copyWith(color: Colors.white54),
          ),
        ],
      ),
    );
  }
}

class _SectionCard extends StatelessWidget {
  final List<Widget> children;

  const _SectionCard({required this.children});

  @override
  Widget build(BuildContext context) {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: children,
        ),
      ),
    );
  }
}

class _InfoRow extends StatelessWidget {
  final String label;
  final String value;
  final bool muted;

  const _InfoRow({
    required this.label,
    required this.value,
    this.muted = false,
  });

  @override
  Widget build(BuildContext context) {
    final valueStyle = Theme.of(context).textTheme.bodyMedium?.copyWith(
      color: muted ? Colors.white54 : null,
      fontWeight: FontWeight.w600,
    );

    return Padding(
      padding: const EdgeInsets.only(bottom: 10),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(
            label,
            style: Theme.of(
              context,
            ).textTheme.bodySmall?.copyWith(color: Colors.white54),
          ),
          const SizedBox(height: 2),
          Text(value, style: valueStyle),
        ],
      ),
    );
  }
}

class _StatusTile extends StatelessWidget {
  final IconData icon;
  final Color color;
  final String title;
  final String subtitle;

  const _StatusTile({
    required this.icon,
    required this.color,
    required this.title,
    required this.subtitle,
  });

  @override
  Widget build(BuildContext context) {
    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Icon(icon, color: color),
        const SizedBox(width: 12),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(title, style: const TextStyle(fontWeight: FontWeight.w700)),
              const SizedBox(height: 2),
              Text(subtitle, style: const TextStyle(color: Colors.white54)),
            ],
          ),
        ),
      ],
    );
  }
}

class _EmptySectionState extends StatelessWidget {
  final IconData icon;
  final String title;
  final String message;

  const _EmptySectionState({
    required this.icon,
    required this.title,
    required this.message,
  });

  @override
  Widget build(BuildContext context) {
    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Icon(icon, color: Colors.white38),
        const SizedBox(width: 12),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(title, style: const TextStyle(fontWeight: FontWeight.w700)),
              const SizedBox(height: 2),
              Text(message, style: const TextStyle(color: Colors.white54)),
            ],
          ),
        ),
      ],
    );
  }
}