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

import '../app/error_message.dart';
import '../models/home_config.dart';
import '../providers/providers.dart';
import '../widgets/build_info_text.dart';
import 'home_edit_screen.dart';
import 'remote_screen.dart';

/// Экран "Дома" -- список серверов Ignis.
/// Пользователь может добавить, удалить, переключить активный дом.
class HomesScreen extends ConsumerStatefulWidget {
  const HomesScreen({super.key});

  @override
  ConsumerState<HomesScreen> createState() => _HomesScreenState();
}

class _HomesScreenState extends ConsumerState<HomesScreen>
    with WidgetsBindingObserver {
  late final UserLocationNotifier _userLocationNotifier;
  bool _isWatchingLocation = false;
  String? _switchingHomeId;
  String? _deletingHomeId;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    _userLocationNotifier = ref.read(userLocationProvider.notifier);
    Future.microtask(() async {
      await _syncLocationWatching();
      await _syncGeofenceAutomation();
    });
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    if (_isWatchingLocation) {
      _userLocationNotifier.stopWatching();
    }
    super.dispose();
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (state == AppLifecycleState.resumed) {
      Future.microtask(_refreshEnvironmentState);
    }
  }

  @override
  Widget build(BuildContext context) {
    final homes = ref.watch(homesProvider);
    final currentHome = ref.watch(currentHomeProvider);
    final location = ref.watch(userLocationProvider);

    return Scaffold(
      appBar: AppBar(
        title: const Text('ДОМА'),
        automaticallyImplyLeading: false,
      ),
      body: Column(
        children: [
          Expanded(
            child: homes.isEmpty
                ? const _EmptyHomesView()
                : RefreshIndicator(
                    color: Colors.deepOrange,
                    onRefresh: _refreshEnvironmentState,
                    child: ListView(
                      padding: const EdgeInsets.all(12),
                      children: [
                        ...homes.map((home) {
                          final isActive = currentHome?.id == home.id;
                          final isSwitching = _switchingHomeId == home.id;
                          final isDeleting = _deletingHomeId == home.id;
                          final isBusy = isSwitching || isDeleting;
                          final distKm = location.distanceToKm(
                            home.latitude,
                            home.longitude,
                          );

                          return Card(
                            margin: const EdgeInsets.only(bottom: 8),
                            child: ListTile(
                              enabled: !isBusy,
                              leading: Icon(
                                Icons.home,
                                color: isActive
                                    ? Colors.deepOrange
                                    : Colors.white38,
                                size: 28,
                              ),
                              title: Text(
                                home.name,
                                style: TextStyle(
                                  fontWeight: isActive
                                      ? FontWeight.bold
                                      : FontWeight.normal,
                                  color: isActive
                                      ? Colors.deepOrange
                                      : Colors.white,
                                ),
                              ),
                              subtitle: _HomeSubtitle(
                                home: home,
                                location: location,
                                distKm: distKm,
                                isActive: isActive,
                              ),
                              trailing: Row(
                                mainAxisSize: MainAxisSize.min,
                                children: [
                                  if (isBusy)
                                    const SizedBox(
                                      width: 20,
                                      height: 20,
                                      child: CircularProgressIndicator(
                                        strokeWidth: 2,
                                      ),
                                    )
                                  else ...[
                                    IconButton(
                                      icon: const Icon(
                                        Icons.edit,
                                        size: 20,
                                        color: Colors.white38,
                                      ),
                                      onPressed: () => _editHome(context, home),
                                    ),
                                    IconButton(
                                      icon: const Icon(
                                        Icons.delete_outline,
                                        size: 20,
                                        color: Colors.redAccent,
                                      ),
                                      onPressed: () =>
                                          _confirmDelete(context, home),
                                    ),
                                  ],
                                ],
                              ),
                              onTap: isBusy
                                  ? null
                                  : () => _selectHome(context, home),
                            ),
                          );
                        }),
                      ],
                    ),
                  ),
          ),
          const SafeArea(
            top: false,
            minimum: EdgeInsets.only(bottom: 10),
            child: Padding(
              padding: EdgeInsets.only(bottom: 6),
              child: BuildInfoText(),
            ),
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        backgroundColor: Colors.deepOrange,
        onPressed: () => _addHome(context),
        child: const Icon(Icons.add),
      ),
    );
  }

  void _selectHome(BuildContext context, HomeConfig home) async {
    if (_switchingHomeId != null || _deletingHomeId != null) return;

    setState(() => _switchingHomeId = home.id);
    final messenger = ScaffoldMessenger.of(context);
    try {
      await ref.read(currentHomeProvider.notifier).select(home);
      if (context.mounted) {
        Navigator.of(context).pushReplacement(
          MaterialPageRoute(builder: (_) => const RemoteScreen()),
        );
      }
    } catch (e) {
      if (context.mounted) {
        messenger.showSnackBar(
          SnackBar(
            content: Text('Не удалось выбрать дом: ${describeLoadError(e)}'),
          ),
        );
      }
    } finally {
      if (mounted) {
        setState(() => _switchingHomeId = null);
      }
    }
  }

  Future<void> _addHome(BuildContext context) async {
    await Navigator.of(
      context,
    ).push(MaterialPageRoute(builder: (_) => const HomeEditScreen()));
    await _refreshEnvironmentState();
  }

  Future<void> _editHome(BuildContext context, HomeConfig home) async {
    await Navigator.of(
      context,
    ).push(MaterialPageRoute(builder: (_) => HomeEditScreen(home: home)));
    await _refreshEnvironmentState();
  }

  void _confirmDelete(BuildContext context, HomeConfig home) {
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('Удалить дом?'),
        content: Text('Удалить "${home.name}" (${home.url})?'),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(ctx).pop(),
            child: const Text('Отмена'),
          ),
          TextButton(
            onPressed: () async {
              Navigator.of(ctx).pop();
              await _deleteHome(context, home);
            },
            child: const Text(
              'Удалить',
              style: TextStyle(color: Colors.redAccent),
            ),
          ),
        ],
      ),
    );
  }

  Future<void> _deleteHome(BuildContext context, HomeConfig home) async {
    if (_switchingHomeId != null || _deletingHomeId != null) return;

    final deletedCurrentHome = ref.read(currentHomeProvider)?.id == home.id;
    setState(() => _deletingHomeId = home.id);
    final messenger = ScaffoldMessenger.of(context);

    try {
      await ref.read(homesProvider.notifier).remove(home.id);
      await ref.read(currentHomeProvider.notifier).load();
      if (deletedCurrentHome) {
        ref.read(authInfoProvider.notifier).clear();
      }
      await _refreshEnvironmentState();
    } catch (e) {
      if (context.mounted) {
        messenger.showSnackBar(
          SnackBar(
            content: Text('Не удалось удалить дом: ${describeLoadError(e)}'),
          ),
        );
      }
    } finally {
      if (mounted) {
        setState(() => _deletingHomeId = null);
      }
    }
  }

  Future<void> _refreshEnvironmentState() async {
    await _syncLocationWatching();
    if (_isWatchingLocation) {
      await _userLocationNotifier.refresh();
    }
    await _syncGeofenceAutomation();
  }

  Future<void> _syncGeofenceAutomation() async {
    await ref
        .read(geofenceAutomationServiceProvider)
        .syncActiveHome(ref.read(currentHomeProvider));
  }

  Future<void> _syncLocationWatching() async {
    final shouldWatch = ref.read(homesProvider).any((home) => home.hasCoordinates);
    if (shouldWatch == _isWatchingLocation) {
      return;
    }

    if (shouldWatch) {
      await _userLocationNotifier.startWatching();
      _isWatchingLocation = true;
      return;
    }

    _userLocationNotifier.stopWatching();
    _isWatchingLocation = false;
  }
}

class _EmptyHomesView extends StatelessWidget {
  const _EmptyHomesView();

  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Icon(Icons.home_outlined, size: 64, color: Colors.white24),
          SizedBox(height: 16),
          Text(
            'Нет добавленных домов',
            style: TextStyle(color: Colors.white54, fontSize: 16),
          ),
          SizedBox(height: 8),
          Text(
            'Добавьте сервер Ignis',
            style: TextStyle(color: Colors.white38, fontSize: 14),
          ),
        ],
      ),
    );
  }
}

class _HomeSubtitle extends StatelessWidget {
  final HomeConfig home;
  final UserLocation location;
  final double? distKm;
  final bool isActive;

  const _HomeSubtitle({
    required this.home,
    required this.location,
    required this.distKm,
    required this.isActive,
  });

  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(
          home.url,
          style: const TextStyle(color: Colors.white38, fontSize: 12),
        ),
        if (distKm != null)
          Padding(
            padding: const EdgeInsets.only(top: 2),
            child: Row(
              children: [
                const Icon(Icons.near_me, size: 11, color: Colors.white30),
                const SizedBox(width: 4),
                Text(
                  '~${formatDistance(distKm!)}',
                  style: const TextStyle(color: Colors.white30, fontSize: 11),
                ),
              ],
            ),
          )
        else if (home.hasCoordinates && !location.hasPosition)
          Padding(
            padding: const EdgeInsets.only(top: 2),
            child: Row(
              children: [
                const Icon(Icons.location_on, size: 12, color: Colors.white24),
                const SizedBox(width: 4),
                Text(
                  location.error ?? 'Координаты заданы',
                  style: const TextStyle(color: Colors.white24, fontSize: 11),
                ),
              ],
            ),
          )
        else if (home.geofenceReady && isActive)
          Padding(
            padding: const EdgeInsets.only(top: 2),
            child: Row(
              children: [
                const Icon(
                  Icons.shield_moon_outlined,
                  size: 12,
                  color: Colors.deepOrangeAccent,
                ),
                const SizedBox(width: 4),
                Text(
                  'Автовыключение: ${home.geofenceRadiusMeters} м',
                  style: const TextStyle(
                    color: Colors.deepOrangeAccent,
                    fontSize: 11,
                  ),
                ),
              ],
            ),
          )
        else if (home.geofenceReady)
          Padding(
            padding: const EdgeInsets.only(top: 2),
            child: Row(
              children: [
                const Icon(
                  Icons.shield_moon_outlined,
                  size: 12,
                  color: Colors.white24,
                ),
                const SizedBox(width: 4),
                Text(
                  'Автовыключение: ${home.geofenceRadiusMeters} м',
                  style: const TextStyle(color: Colors.white24, fontSize: 11),
                ),
              ],
            ),
          ),
      ],
    );
  }
}