import 'package:flutter/material.dart';
import 'package:flutter_staggered_grid_view/flutter_staggered_grid_view.dart';
import 'publish_screen.dart';
import 'activity_detail_screen.dart';
import 'friends_screen.dart';
import 'messages_screen.dart';
import 'profile_screen.dart';

class ActivityListScreen extends StatefulWidget {
  @override
  _ActivityListScreenState createState() => _ActivityListScreenState();
}

class _ActivityListScreenState extends State<ActivityListScreen> {
  int _selectedIndex = 0;
  bool _showFriendsOverlay = false;
  final _feedKey = GlobalKey<RefreshIndicatorState>();
  String? _selectedTime;

  // 模拟活动数据
  final List<Map<String, dynamic>> activities = [
    {
      'title': '周末公园太极拳',
      'date': '今天 07:30',
      'location': '人民公园',
      'participants': 12,
      'image': 'https://picsum.photos/seed/1/400/300',
      'creator': '王阿姨',
      'avatarSeed': 11,
    },
    {
      'title': '社区书法班开课啦',
      'date': '明天 09:00',
      'location': '社区活动中心',
      'participants': 8,
      'image': 'https://picsum.photos/seed/2/400/500',
      'creator': '李老师',
      'avatarSeed': 22,
    },
    {
      'title': '广场舞队招新',
      'date': '本周三 19:00',
      'location': '中央广场',
      'participants': 25,
      'image': 'https://picsum.photos/seed/3/400/400',
      'creator': '张姐',
      'avatarSeed': 33,
    },
    {
      'title': '老年摄影兴趣小组',
      'date': '本周四 14:00',
      'location': '文化馆',
      'participants': 15,
      'image': 'https://picsum.photos/seed/4/400/350',
      'creator': '陈叔',
      'avatarSeed': 44,
    },
    {
      'title': '周三棋牌活动',
      'date': '本周五 16:00',
      'location': '社区会所',
      'participants': 20,
      'image': 'https://picsum.photos/seed/5/400/450',
      'creator': '赵大哥',
      'avatarSeed': 55,
    },
    {
      'title': '健康养生讲座',
      'date': '${DateTime.now().month}月${DateTime.now().day}日 10:30',
      'location': '图书馆',
      'participants': 30,
      'image': 'https://picsum.photos/seed/6/400/380',
      'creator': '刘阿姨',
      'avatarSeed': 66,
    },
  ];

  Future<void> _refreshActivities() async {
    if (!mounted) return;
    setState(() {
      activities.shuffle();
    });
    await Future.delayed(const Duration(milliseconds: 200));
  }

  void _onItemTapped(int index) {
    if (index == 2) {
      // 中间按钮 - 跳转到发布页面
      Navigator.push(
        context,
        MaterialPageRoute(builder: (context) => PublishScreen()),
      );
      return;
    }

    if (index == 1) {
      setState(() {
        _showFriendsOverlay = !_showFriendsOverlay;
        if (_showFriendsOverlay) {
          _selectedIndex = 0;
        }
      });
      return;
    }

    if (index == 0 && _selectedIndex == 0 && !_showFriendsOverlay) {
      _feedKey.currentState?.show();
      return;
    }

    if (_selectedIndex != index || _showFriendsOverlay) {
      setState(() {
        _selectedIndex = index;
        _showFriendsOverlay = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    // When showing messages or profile, use their own Scaffold directly
    if (_selectedIndex == 3 || _selectedIndex == 4) {
      return Scaffold(
        backgroundColor: const Color(0xFFFFF8F0),
        body: _buildBodyWithFriendsOverlay(),
        bottomNavigationBar: _buildBottomNavigationBar(),
      );
    }
    return Scaffold(
      backgroundColor: const Color(0xFFFFF8F0),
      appBar: _showFriendsOverlay
          ? null
          : AppBar(
              title: Text('伴享', style: TextStyle(fontWeight: FontWeight.bold)),
              centerTitle: true,
              actions: [
                IconButton(
                  icon: Icon(Icons.search),
                  onPressed: () {},
                ),
                IconButton(
                  icon: Icon(Icons.notifications_none),
                  onPressed: () {},
                ),
              ],
            ),
      body: _buildBodyWithFriendsOverlay(),
      bottomNavigationBar: _buildBottomNavigationBar(),
      floatingActionButton: _buildFloatingActionButton(),
      floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
    );
  }

  Widget _buildBody() {
    switch (_selectedIndex) {
      case 3:
        return const MessagesScreen();
      case 4:
        return const ProfileScreen();
      default:
        return _buildFeed();
    }
  }

  Widget _buildBodyWithFriendsOverlay() {
    return Stack(
      children: [
        _buildBody(),
        if (_showFriendsOverlay) const Positioned.fill(child: FriendsScreen()),
      ],
    );
  }

  Widget _buildFeed() {
    final filteredActivities = _getFilteredActivities();
    return RefreshIndicator(
      key: _feedKey,
      onRefresh: _refreshActivities,
      child: ListView(
        physics: const AlwaysScrollableScrollPhysics(),
        padding: const EdgeInsets.all(12),
        children: [
          _buildTimeFilterChips(),
          const SizedBox(height: 12),
          MasonryGridView.count(
            shrinkWrap: true,
            physics: const NeverScrollableScrollPhysics(),
            crossAxisCount: 2,
            mainAxisSpacing: 10,
            crossAxisSpacing: 10,
            itemCount: filteredActivities.length,
            itemBuilder: (context, index) {
              return _buildActivityCard(filteredActivities[index], index);
            },
          ),
        ],
      ),
    );
  }

  Widget _buildTimeFilterChips() {
    const timeOptions = ['今天', '明天', '本周'];
    return SingleChildScrollView(
      scrollDirection: Axis.horizontal,
      child: Row(
        children: timeOptions.map((time) {
          final isSelected = _selectedTime == time;
          return Padding(
            padding: const EdgeInsets.only(right: 8),
            child: ChoiceChip(
              label: Text(time),
              selected: isSelected,
              onSelected: (_) {
                setState(() {
                  _selectedTime = isSelected ? null : time;
                });
              },
              selectedColor: const Color(0xFFFF6B35),
              labelStyle: TextStyle(
                color: isSelected ? Colors.white : const Color(0xFF666666),
                fontWeight: FontWeight.w600,
              ),
              backgroundColor: const Color(0xFFFFEFE3),
            ),
          );
        }).toList(),
      ),
    );
  }

  List<Map<String, dynamic>> _getFilteredActivities() {
    if (_selectedTime == null || _selectedTime == '本周') {
      return activities;
    }

    final todayLabel = '${DateTime.now().month}月${DateTime.now().day}日';
    return activities.where((activity) {
      final dateText = (activity['date'] ?? '').toString();
      if (_selectedTime == '今天') {
        return dateText.contains('今天') || dateText.contains(todayLabel);
      }
      if (_selectedTime == '明天') {
        return dateText.contains('明天');
      }
      return true;
    }).toList();
  }

  Widget _buildActivityCard(Map<String, dynamic> activity, int index) {
    final imageHeight = index.isOdd ? 160.0 : 210.0;
    final coverUrl =
        'https://picsum.photos/seed/${activity['title'].hashCode.abs()}/400/300';

    return GestureDetector(
      onTap: () {
        // 跳转到详情页
        Navigator.push(
          context,
          MaterialPageRoute(
            builder: (context) => ActivityDetailScreen(activity: activity),
          ),
        );
      },
      child: Container(
        decoration: BoxDecoration(
          color: Colors.white,
          borderRadius: BorderRadius.circular(12),
          boxShadow: [
            BoxShadow(
              color: Colors.black.withOpacity(0.06),
              blurRadius: 6,
              offset: Offset(0, 2),
            ),
          ],
        ),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            // 封面图片
            ClipRRect(
              borderRadius: BorderRadius.vertical(top: Radius.circular(12)),
              child: SizedBox(
                height: imageHeight,
                width: double.infinity,
                child: Image.network(
                  coverUrl,
                  fit: BoxFit.cover,
                  errorBuilder: (context, error, stackTrace) {
                    return Container(
                      color: Colors.grey[200],
                      alignment: Alignment.center,
                      child: Icon(
                        Icons.image_outlined,
                        size: 40,
                        color: Colors.grey[400],
                      ),
                    );
                  },
                ),
              ),
            ),
            // 标题和信息
            Padding(
              padding: EdgeInsets.all(8),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    activity['title'],
                    style: TextStyle(
                      fontSize: 14,
                      fontWeight: FontWeight.bold,
                      color: Color(0xFF333333),
                    ),
                    maxLines: 2,
                    overflow: TextOverflow.ellipsis,
                  ),
                  SizedBox(height: 4),
                  Row(
                    children: [
                      SizedBox(
                        width: 32,
                        height: 32,
                        child: ClipOval(
                          child: Image.network(
                            'https://i.pravatar.cc/40?img=${activity['avatarSeed']}',
                            fit: BoxFit.cover,
                            errorBuilder: (context, error, stackTrace) {
                              return Container(
                                color: Colors.grey[200],
                                alignment: Alignment.center,
                                child: Icon(
                                  Icons.person,
                                  size: 16,
                                  color: Colors.grey[500],
                                ),
                              );
                            },
                          ),
                        ),
                      ),
                      SizedBox(width: 8),
                      Expanded(
                        flex: 3,
                        child: Text(
                          activity['creator'],
                          style: TextStyle(
                            fontSize: 12,
                            color: Color(0xFF999999),
                          ),
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                        ),
                      ),
                      Spacer(flex: 1),
                      Text(
                        '${activity['participants']}人',
                        style: TextStyle(
                          fontSize: 12,
                          color: Color(0xFFFF6B35),
                        ),
                      ),
                    ],
                  ),
                  SizedBox(height: 6),
                  Row(
                    children: [
                      Icon(
                        Icons.access_time,
                        size: 13,
                        color: Color(0xFF999999),
                      ),
                      SizedBox(width: 4),
                      Expanded(
                        child: Text(
                          activity['date'] ?? '',
                          style: TextStyle(
                            fontSize: 12,
                            color: Color(0xFF999999),
                          ),
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                        ),
                      ),
                    ],
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildBottomNavigationBar() {
    return Container(
      decoration: BoxDecoration(
        color: Colors.white,
        boxShadow: [
          BoxShadow(
            color: Colors.black.withOpacity(0.05),
            blurRadius: 10,
            offset: Offset(0, -2),
          ),
        ],
      ),
      child: SafeArea(
        child: Container(
          height: 60,
          child: Row(
            children: [
              _buildNavItem(0, Icons.home, '首页'),
              _buildNavItem(1, Icons.people, '好友'),
              SizedBox(width: 60), // 中间按钮占位
              _buildNavItem(3, Icons.message, '消息'),
              _buildNavItem(4, Icons.person, '我的'),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildNavItem(int index, IconData icon, String label) {
    final isSelected = index == 1 ? _showFriendsOverlay : _selectedIndex == index;
    return Expanded(
      child: GestureDetector(
        onTap: () => _onItemTapped(index),
        behavior: HitTestBehavior.opaque,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              icon,
              color: isSelected ? Color(0xFFFF6B35) : Color(0xFF999999),
              size: 24,
            ),
            SizedBox(height: 4),
            Text(
              label,
              style: TextStyle(
                fontSize: 11,
                color: isSelected ? Color(0xFFFF6B35) : Color(0xFF999999),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildFloatingActionButton() {
    return Container(
      width: 56,
      height: 56,
      margin: EdgeInsets.only(top: 30),
      decoration: BoxDecoration(
        shape: BoxShape.circle,
        gradient: LinearGradient(
          colors: [Color(0xFFFF6B35), Color(0xFFFFB84D)],
          begin: Alignment.topLeft,
          end: Alignment.bottomRight,
        ),
        boxShadow: [
          BoxShadow(
            color: Color(0xFFFF6B35).withOpacity(0.4),
            blurRadius: 12,
            offset: Offset(0, 4),
          ),
        ],
      ),
      child: Material(
        color: Colors.transparent,
        child: InkWell(
          onTap: () => _onItemTapped(2),
          customBorder: CircleBorder(),
          child: Icon(Icons.add, color: Colors.white, size: 28),
        ),
      ),
    );
  }
}