import 'dart:ui';

import 'package:fluent_ui/fluent_ui.dart';
import 'package:flutter/material.dart' show SegmentedButton, ButtonSegment;
import 'package:task_hub/models/task.dart';
import 'package:task_hub/widgets/task_dialog.dart';
import 'package:task_hub/widgets/task_item.dart';

// 任务页面
class TaskPage extends StatefulWidget {
  const TaskPage({super.key});

  @override
  State<TaskPage> createState() => _TaskPageState();
}

class _TaskPageState extends State<TaskPage> {
  final List<Task> _tasks = [];
  String _filter = 'all';
  String _sortBy = 'created';

  List<Task> get _filteredTasks {
    List<Task> tasks = _tasks.where((task) {
      if (_filter == 'active') return !task.isCompleted;
      if (_filter == 'completed') return task.isCompleted;
      return true;
    }).toList();

    tasks.sort((a, b) {
      switch (_sortBy) {
        case 'due':
          if (a.dueDate == null && b.dueDate == null) return 0;
          if (a.dueDate == null) return 1;
          if (b.dueDate == null) return -1;
          return a.dueDate!.compareTo(b.dueDate!);
        case 'priority':
          return b.priority.index.compareTo(a.priority.index);
        case 'created':
        default:
          return b.createTime.compareTo(a.createTime);
      }
    });

    return tasks;
  }

  void _addTask() {
    showDialog(
      context: context,
      builder: (context) => TaskDialog(
        onSave: (task) {
          setState(() {
            _tasks.add(task);
          });
        },
      ),
    );
  }

  void _editTask(Task task) {
    showDialog(
      context: context,
      builder: (context) => TaskDialog(
        task: task,
        onSave: (editedTask) {
          setState(() {
            final index = _tasks.indexWhere((t) => t.id == task.id);
            if (index != -1) {
              _tasks[index] = editedTask;
            }
          });
        },
      ),
    );
  }

  void _deleteTask(int taskId) {
    setState(() {
      _tasks.removeWhere((task) => task.id == taskId);
    });
  }

  void _toggleTaskComplete(Task task) {
    setState(() {
      final index = _tasks.indexWhere((t) => t.id == task.id);
      if (index != -1) {
        _tasks[index] = Task(
          id: task.id,
          title: task.title,
          desc: task.desc,
          createTime: task.createTime,
          dueDate: task.dueDate,
          isCompleted: !task.isCompleted,
          priority: task.priority
        );
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return ScaffoldPage.withPadding(
      header: PageHeader(
        title: const Text('待办任务'),
        commandBar: CommandBar(
          mainAxisAlignment: MainAxisAlignment.end,
          primaryItems: [
            CommandBarButton(
              icon: const Icon(FluentIcons.add),
              label: const Text('添加任务'),
              onPressed: _addTask,
            ),
          ],
        ),
      ),
      content: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          _buildStatsWidget(),
          const SizedBox(height: 16),
          _buildFilterWidget(),
          const SizedBox(height: 16),
          Expanded(
            child: _tasks.isEmpty ? _buildEmptyTask() : _buildTaskList(),
          ),
        ],
      ),
    );
  }

  Widget _buildStatsWidget() {
    final completedCount = _tasks.where((task) => task.isCompleted).length;
    final activeCount = _tasks.length - completedCount;

    return Card(
      backgroundColor: FluentTheme.of(context).accentColor.lighter,
      child: Padding(
        padding: const EdgeInsets.all(12.0),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          children: [
            _buildStatsItem('全部', '${_tasks.length}'),
            _buildStatsItem('进行中', '$activeCount'),
            _buildStatsItem('已完成', '$completedCount'),
          ],
        ),
      ),
    );
  }

  Widget _buildStatsItem(String label, String value) {
    return Column(
      children: [
        Text(
          value,
          style: TextStyle(
            fontSize: 24,
            fontWeight: FontWeight.bold,
            color: Colors.white,
          ),
        ),
        const SizedBox(height: 4),
        Text(label, style: TextStyle(color: Colors.white)),
      ],
    );
  }

  Widget _buildFilterWidget() {
    return Card(
      borderColor: Colors.white,
      child: Padding(
        padding: const EdgeInsets.all(12.0),
        child: Row(
          children: [
            const Text('筛选:'),
            const SizedBox(width: 8),
            SegmentedButton<String>(
              showSelectedIcon: false,
              selected: <String>{_filter},
              onSelectionChanged: (Set<String> value) {
                setState(() {
                  _filter = value.first;
                });
              },
              segments: const [
                ButtonSegment(
                  value: 'all',
                  label: Text('全部', style: TextStyle(fontFamily: 'CustomFont')),
                ),
                ButtonSegment(
                  value: 'active',
                  label: Text(
                    '进行中',
                    style: TextStyle(fontFamily: 'CustomFont'),
                  ),
                ),
                ButtonSegment(
                  value: 'completed',
                  label: Text(
                    '已完成',
                    style: TextStyle(fontFamily: 'CustomFont'),
                  ),
                ),
              ],
            ),
            const Spacer(),
            const Text('排序:'),
            const SizedBox(width: 8),
            ComboBox<String>(
              value: _sortBy,
              items: const [
                ComboBoxItem(value: 'created', child: Text('创建时间')),
                ComboBoxItem(value: 'due', child: Text('截止日期')),
                ComboBoxItem(value: 'priority', child: Text('优先级')),
              ],
              onChanged: (value) {
                if (value != null) {
                  setState(() {
                    _sortBy = value;
                  });
                }
              },
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildEmptyTask() {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Icon(
            FluentIcons.check_list,
            size: 64,
            color: FluentTheme.of(context).accentColor,
          ),
          const SizedBox(height: 20),
          const Text(
            '还没有任务',
            style: TextStyle(fontSize: 20, color: Colors.grey),
          ),
          const SizedBox(height: 10),
          Text('点击右上角的"添加任务"按钮开始', style: TextStyle(color: Colors.grey)),
        ],
      ),
    );
  }

  Widget _buildTaskList() {
    return ListView.builder(
      itemCount: _filteredTasks.length,
      itemBuilder: (context, index) {
        final task = _filteredTasks[index];
        return Padding(
          padding: const EdgeInsets.only(bottom: 8.0),
          child: TaskItem(
            task: task,
            onToggleComplete: () => _toggleTaskComplete(task),
            onEdit: () => _editTask(task),
            onDelete: () => _deleteTask(task.id),
          ),
        );
      },
    );
  }
}