import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../app/error_message.dart';
import '../app/load_state.dart';
import '../models/schedule_task.dart';
import '../providers/providers.dart';
import '../widgets/load_error_view.dart';

/// Экран управления расписаниями.
/// Показывает все задачи (one-shot и cron), позволяет создавать и удалять.
class SchedulesScreen extends ConsumerStatefulWidget {
  const SchedulesScreen({super.key});

  @override
  ConsumerState<SchedulesScreen> createState() => _SchedulesScreenState();
}

class _SchedulesScreenState extends ConsumerState<SchedulesScreen> {
  @override
  void initState() {
    super.initState();
    _load();
  }

  Future<void> _load() async {
    await ref.read(tasksProvider.notifier).load();
  }

  @override
  Widget build(BuildContext context) {
    final tasksState = ref.watch(tasksProvider);
    final tasks = tasksState.data;

    return Scaffold(
      appBar: AppBar(title: const Text('РАСПИСАНИЯ')),
      body: _buildContent(tasksState, tasks),
      floatingActionButton: FloatingActionButton(
        backgroundColor: Colors.deepOrange,
        onPressed: () => _showAddDialog(context),
        child: const Icon(Icons.add),
      ),
    );
  }

  /// Диалог создания расписания
  void _showAddDialog(BuildContext context) {
    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      backgroundColor: const Color(0xFF1E1E1E),
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
      ),
      builder: (ctx) => const _AddScheduleSheet(),
    );
  }

  Widget _buildContent(
    LoadState<List<ScheduleTask>> tasksState,
    List<ScheduleTask> tasks,
  ) {
    if ((tasksState.isIdle || tasksState.isLoading) && tasks.isEmpty) {
      return const Center(
        child: CircularProgressIndicator(color: Colors.deepOrange),
      );
    }

    if (tasksState.hasError && tasks.isEmpty) {
      return LoadErrorView(
        title: 'Не удалось загрузить расписания',
        message: tasksState.errorMessage,
        icon: Icons.schedule,
        onRetry: _load,
      );
    }

    if (tasks.isEmpty) {
      return const Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(Icons.schedule, size: 64, color: Colors.white24),
            SizedBox(height: 16),
            Text(
              'Нет активных расписаний',
              style: TextStyle(color: Colors.white54, fontSize: 16),
            ),
          ],
        ),
      );
    }

    final hasStatusHeader = tasksState.isLoading || tasksState.hasError;
    final statusHeaderCount = hasStatusHeader ? 1 : 0;

    return RefreshIndicator(
      color: Colors.deepOrange,
      onRefresh: _load,
      child: ListView.builder(
        physics: const AlwaysScrollableScrollPhysics(),
        padding: const EdgeInsets.all(12),
        itemCount: tasks.length + statusHeaderCount,
        itemBuilder: (context, index) {
          if (hasStatusHeader && index == 0) {
            if (tasksState.isLoading) {
              return const Padding(
                padding: EdgeInsets.only(bottom: 12),
                child: LinearProgressIndicator(color: Colors.deepOrange),
              );
            }

            return LoadErrorBanner(
              title: 'Не удалось обновить расписания',
              message: tasksState.errorMessage,
              onRetry: _load,
            );
          }

          final taskIndex = index - statusHeaderCount;
          return _TaskCard(task: tasks[taskIndex]);
        },
      ),
    );
  }
}

/// Карточка одной задачи расписания
class _TaskCard extends ConsumerWidget {
  final ScheduleTask task;

  const _TaskCard({required this.task});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return Card(
      margin: const EdgeInsets.only(bottom: 8),
      child: ListTile(
        leading: Icon(
          task.isCron ? Icons.repeat : Icons.timer,
          color: Colors.deepOrange,
        ),
        title: Text(
          task.title,
          style: const TextStyle(fontWeight: FontWeight.bold),
        ),
        subtitle: Text(
          task.subtitle,
          style: const TextStyle(fontSize: 12, color: Colors.white54),
        ),
        trailing: IconButton(
          icon: const Icon(Icons.delete_outline, color: Colors.redAccent),
          onPressed: () => _confirmCancel(context, ref, task.jobId),
        ),
      ),
    );
  }

  void _confirmCancel(BuildContext context, WidgetRef ref, String jobId) {
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('Отменить задачу?'),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(ctx).pop(),
            child: const Text('Нет'),
          ),
          TextButton(
            onPressed: () async {
              Navigator.of(ctx).pop();
              try {
                await ref.read(tasksProvider.notifier).cancel(jobId);
              } catch (e) {
                if (!context.mounted) return;
                ScaffoldMessenger.of(context).showSnackBar(
                  SnackBar(
                    content: Text(
                      'Ошибка отмены задачи: ${describeLoadError(e)}',
                    ),
                  ),
                );
              }
            },
            child: const Text('Да', style: TextStyle(color: Colors.redAccent)),
          ),
        ],
      ),
    );
  }
}

/// Нижний лист для создания расписания
class _AddScheduleSheet extends ConsumerStatefulWidget {
  const _AddScheduleSheet();

  @override
  ConsumerState<_AddScheduleSheet> createState() => _AddScheduleSheetState();
}

class _AddScheduleSheetState extends ConsumerState<_AddScheduleSheet> {
  /// Тип: 'once' или 'cron'
  String _type = 'once';

  /// Общие поля
  String? _selectedGroupId;
  bool _targetState = false; // включить или выключить

  /// Поля для once
  int _hoursFromNow = 4;

  /// Поля для cron
  final _hourCtrl = TextEditingController(text: '22');
  final _minuteCtrl = TextEditingController(text: '00');
  final _dowCtrl = TextEditingController(text: '*');

  @override
  void dispose() {
    _hourCtrl.dispose();
    _minuteCtrl.dispose();
    _dowCtrl.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final groups = ref.watch(groupsProvider);
    final bottomPadding = MediaQuery.of(context).viewInsets.bottom;
    final systemPadding = MediaQuery.of(context).padding.bottom;

    return Padding(
      padding: EdgeInsets.only(
        left: 20,
        right: 20,
        top: 20,
        bottom: bottomPadding + systemPadding + 20,
      ),
      child: SingleChildScrollView(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            // Заголовок
            const Text(
              'Новое расписание',
              style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
            ),
            const SizedBox(height: 16),

            // Тип расписания
            Row(
              children: [
                ChoiceChip(
                  label: const Text('Таймер'),
                  selected: _type == 'once',
                  selectedColor: Colors.deepOrange,
                  onSelected: (_) => setState(() => _type = 'once'),
                ),
                const SizedBox(width: 8),
                ChoiceChip(
                  label: const Text('Cron (повтор)'),
                  selected: _type == 'cron',
                  selectedColor: Colors.deepOrange,
                  onSelected: (_) => setState(() => _type = 'cron'),
                ),
              ],
            ),
            const SizedBox(height: 16),

            // Выбор группы
            DropdownButtonFormField<String>(
              initialValue: _selectedGroupId,
              decoration: const InputDecoration(labelText: 'Группа'),
              items: groups.map((g) {
                final id = g.id;
                final name = g.name;
                return DropdownMenuItem(value: id, child: Text(name));
              }).toList(),
              onChanged: (v) => setState(() => _selectedGroupId = v),
            ),
            const SizedBox(height: 12),

            // Действие: включить / выключить
            SwitchListTile(
              title: Text(_targetState ? 'Включить' : 'Выключить'),
              subtitle: const Text('Действие при срабатывании'),
              value: _targetState,
              activeThumbColor: Colors.deepOrange,
              onChanged: (v) => setState(() => _targetState = v),
              contentPadding: EdgeInsets.zero,
            ),
            const SizedBox(height: 12),

            // ─── Once: через сколько часов ───
            if (_type == 'once') ...[
              Text(
                'Через $_hoursFromNow ч.',
                style: const TextStyle(color: Colors.white70),
              ),
              Slider(
                value: _hoursFromNow.toDouble(),
                min: 1,
                max: 24,
                divisions: 23,
                label: '$_hoursFromNow ч.',
                activeColor: Colors.deepOrange,
                onChanged: (v) => setState(() => _hoursFromNow = v.toInt()),
              ),
            ],

            // ─── Cron: час, минута, дни недели ───
            if (_type == 'cron') ...[
              Row(
                children: [
                  Expanded(
                    child: TextField(
                      controller: _hourCtrl,
                      decoration: const InputDecoration(
                        labelText: 'Час (0-23)',
                      ),
                      keyboardType: TextInputType.number,
                    ),
                  ),
                  const SizedBox(width: 12),
                  Expanded(
                    child: TextField(
                      controller: _minuteCtrl,
                      decoration: const InputDecoration(
                        labelText: 'Минута (0-59)',
                      ),
                      keyboardType: TextInputType.number,
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 12),
              TextField(
                controller: _dowCtrl,
                decoration: const InputDecoration(
                  labelText: 'Дни недели (* = каждый, 0-6 = вс-сб)',
                  helperText: 'Например: 1-5 (пн-пт), 0,6 (выходные)',
                ),
              ),
            ],

            const SizedBox(height: 20),

            // Кнопка создания
            SizedBox(
              width: double.infinity,
              height: 48,
              child: ElevatedButton(
                style: ElevatedButton.styleFrom(
                  backgroundColor: Colors.deepOrange,
                  foregroundColor: Colors.white,
                ),
                onPressed: _selectedGroupId == null ? null : _save,
                child: const Text('СОЗДАТЬ'),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Future<void> _save() async {
    if (_selectedGroupId == null) return;

    try {
      if (_type == 'once') {
        await ref
            .read(tasksProvider.notifier)
            .addOnce(
              targetId: _selectedGroupId!,
              targetState: _targetState,
              hoursFromNow: _hoursFromNow,
            );
      } else {
        await ref
            .read(tasksProvider.notifier)
            .addCron(
              targetId: _selectedGroupId!,
              hour: _hourCtrl.text.trim(),
              minute: _minuteCtrl.text.trim(),
              dayOfWeek: _dowCtrl.text.trim(),
              targetState: _targetState,
            );
      }
      if (mounted) Navigator.of(context).pop();
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Ошибка: ${describeLoadError(e)}')),
        );
      }
    }
  }
}