import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import '../providers/task_provider.dart';
import '../models/task_model.dart';

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

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

    return Scaffold(
      appBar: AppBar(
        title: const Text('Задачи'),
        actions: [
          IconButton(
            icon: const Icon(Icons.filter_list),
            onPressed: () => _showFilterDialog(context),
          ),
          IconButton(
            icon: const Icon(Icons.search),
            onPressed: () {},
          ),
        ],
      ),
      body: tasksState.when(
        data: (tasks) {
          if (tasks.isEmpty) {
            return _buildEmptyState(context);
          }

          // Группируем по статусам
          final todoTasks =
              tasks.where((t) => t.status == TaskStatus.todo).toList();
          final inProgressTasks =
              tasks.where((t) => t.status == TaskStatus.inProgress).toList();
          final doneTasks =
              tasks.where((t) => t.status == TaskStatus.done).toList();

          return ListView(
            padding: const EdgeInsets.all(16),
            children: [
              if (todoTasks.isNotEmpty) ...[
                _buildSectionHeader('В планах', todoTasks.length, Colors.blue),
                ...todoTasks.map((task) => _TaskCard(task: task)),
                const SizedBox(height: 16),
              ],
              if (inProgressTasks.isNotEmpty) ...[
                _buildSectionHeader(
                    'В работе', inProgressTasks.length, Colors.orange),
                ...inProgressTasks.map((task) => _TaskCard(task: task)),
                const SizedBox(height: 16),
              ],
              if (doneTasks.isNotEmpty) ...[
                _buildSectionHeader('Готово', doneTasks.length, Colors.green),
                ...doneTasks.map((task) => _TaskCard(task: task)),
              ],
            ],
          );
        },
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (error, stack) => Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              const Icon(Icons.error_outline, size: 48, color: Colors.red),
              const SizedBox(height: 16),
              Text('Ошибка: $error'),
              const SizedBox(height: 16),
              ElevatedButton(
                onPressed: () => ref.refresh(tasksProvider),
                child: const Text('Повторить'),
              ),
            ],
          ),
        ),
      ),
      floatingActionButton: FloatingActionButton.extended(
        onPressed: () async {
          final result = await context
              .push('/home/tasks/new', extra: {'projectId': 'default'});
          if (result == true) {
            ScaffoldMessenger.of(context).showSnackBar(
              const SnackBar(content: Text('✅ Задача создана')),
            );
          }
        },
        icon: const Icon(Icons.add),
        label: const Text('Новая задача'),
      ),
    );
  }

  Widget _buildEmptyState(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          const Icon(
            Icons.task_alt,
            size: 100,
            color: Colors.grey,
          ),
          const SizedBox(height: 24),
          const Text(
            'Нет задач',
            style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
          ),
          const SizedBox(height: 8),
          const Text(
            'Создайте первую задачу',
            style: TextStyle(color: Colors.grey),
          ),
          const SizedBox(height: 32),
          ElevatedButton.icon(
            onPressed: () => context
                .push('/home/tasks/new', extra: {'projectId': 'default'}),
            icon: const Icon(Icons.add),
            label: const Text('Создать задачу'),
          ),
        ],
      ),
    );
  }

  Widget _buildSectionHeader(String title, int count, Color color) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 12),
      child: Row(
        children: [
          Container(
            width: 4,
            height: 20,
            decoration: BoxDecoration(
              color: color,
              borderRadius: BorderRadius.circular(2),
            ),
          ),
          const SizedBox(width: 8),
          Text(
            title,
            style: const TextStyle(fontSize: 16, fontWeight: FontWeight.bold),
          ),
          const SizedBox(width: 8),
          Container(
            padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
            decoration: BoxDecoration(
              color: color.withOpacity(0.2),
              borderRadius: BorderRadius.circular(12),
            ),
            child: Text(
              '$count',
              style: TextStyle(color: color, fontWeight: FontWeight.bold),
            ),
          ),
        ],
      ),
    );
  }

  void _showFilterDialog(BuildContext context) {
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Фильтр задач'),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            ListTile(
              leading: const Icon(Icons.all_inclusive),
              title: const Text('Все задачи'),
              onTap: () => Navigator.pop(context),
            ),
            ListTile(
              leading: const Icon(Icons.pending, color: Colors.blue),
              title: const Text('В планах'),
              onTap: () => Navigator.pop(context),
            ),
            ListTile(
              leading: const Icon(Icons.hourglass_empty, color: Colors.orange),
              title: const Text('В работе'),
              onTap: () => Navigator.pop(context),
            ),
            ListTile(
              leading: const Icon(Icons.check_circle, color: Colors.green),
              title: const Text('Готово'),
              onTap: () => Navigator.pop(context),
            ),
          ],
        ),
      ),
    );
  }
}

class _TaskCard extends ConsumerWidget {
  final TaskModel task;

  const _TaskCard({required this.task});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return Card(
      margin: const EdgeInsets.only(bottom: 12),
      child: ListTile(
        leading: CircleAvatar(
          backgroundColor: _getPriorityColor(task.priority),
          child: Icon(
            _getPriorityIcon(task.priority),
            color: Colors.white,
            size: 20,
          ),
        ),
        title: Text(
          task.title,
          style: TextStyle(
            decoration: task.status == TaskStatus.done
                ? TextDecoration.lineThrough
                : null,
            color: task.status == TaskStatus.done ? Colors.grey : null,
          ),
        ),
        subtitle: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            if (task.description != null && task.description!.isNotEmpty) ...[
              const SizedBox(height: 4),
              Text(
                task.description!,
                maxLines: 2,
                overflow: TextOverflow.ellipsis,
              ),
            ],
            const SizedBox(height: 4),
            Row(
              children: [
                if (task.dueDate != null) ...[
                  Icon(
                    task.isOverdue ? Icons.warning : Icons.calendar_today,
                    size: 12,
                    color: task.isOverdue ? Colors.red : Colors.grey,
                  ),
                  const SizedBox(width: 4),
                  Text(
                    '${task.dueDate!.day}.${task.dueDate!.month}',
                    style: TextStyle(
                      fontSize: 12,
                      color: task.isOverdue ? Colors.red : Colors.grey,
                    ),
                  ),
                  const SizedBox(width: 12),
                ],
                if (task.estimatedHours > 0) ...[
                  const Icon(Icons.timer, size: 12, color: Colors.grey),
                  const SizedBox(width: 4),
                  Text(
                    '${task.estimatedHours}ч',
                    style: const TextStyle(fontSize: 12, color: Colors.grey),
                  ),
                ],
              ],
            ),
          ],
        ),
        trailing: PopupMenuButton<String>(
          onSelected: (value) => _handleMenuAction(context, ref, value),
          itemBuilder: (context) => [
            const PopupMenuItem(value: 'edit', child: Text('Редактировать')),
            const PopupMenuItem(value: 'duplicate', child: Text('Дублировать')),
            const PopupMenuItem(value: 'delete', child: Text('Удалить')),
          ],
        ),
        isThreeLine: true,
        onTap: () => context.push('/home/tasks/${task.id}', extra: {
          'task': task,
          'projectId': task.projectId,
        }),
      ),
    );
  }

  Color _getPriorityColor(TaskPriority priority) {
    switch (priority) {
      case TaskPriority.urgent:
        return Colors.red;
      case TaskPriority.high:
        return Colors.orange;
      case TaskPriority.medium:
        return Colors.blue;
      case TaskPriority.low:
        return Colors.green;
    }
  }

  IconData _getPriorityIcon(TaskPriority priority) {
    switch (priority) {
      case TaskPriority.urgent:
        return Icons.fire_engine;
      case TaskPriority.high:
        return Icons.arrow_upward;
      case TaskPriority.medium:
        return Icons.remove;
      case TaskPriority.low:
        return Icons.arrow_downward;
    }
  }

  void _handleMenuAction(BuildContext context, WidgetRef ref, String action) {
    switch (action) {
      case 'edit':
        context.push('/home/tasks/${task.id}', extra: {
          'task': task,
          'projectId': task.projectId,
        });
        break;
      case 'delete':
        _confirmDelete(context, ref);
        break;
    }
  }

  void _confirmDelete(BuildContext context, WidgetRef ref) {
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Удалить задачу?'),
        content: const Text('Это действие нельзя отменить'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('Отмена'),
          ),
          TextButton(
            onPressed: () {
              ref.read(tasksProvider.notifier).deleteTask(task.id);
              Navigator.pop(context);
              ScaffoldMessenger.of(context).showSnackBar(
                const SnackBar(content: Text('✅ Задача удалена')),
              );
            },
            style: TextButton.styleFrom(foregroundColor: Colors.red),
            child: const Text('Удалить'),
          ),
        ],
      ),
    );
  }
}