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

class PhotoPage extends StatelessWidget {
  const PhotoPage({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: [
          const PhotoTimeline(),
          Positioned(
            top: 0,
            left: 0,
            right: 0,
            child: Container(
              height: 80,
              padding: EdgeInsets.only(top: MediaQuery.of(context).padding.top),
              decoration: BoxDecoration(
                color: Colors.white.withOpacity(0.95),
                boxShadow: [
                  BoxShadow(
                    color: Colors.black.withOpacity(0.1),
                    blurRadius: 4,
                    offset: const Offset(0, 2),
                  ),
                ],
              ),
              child: const Center(
                child: Text(
                  'SnapWish',
                  style: TextStyle(
                    fontSize: 24,
                    fontWeight: FontWeight.bold,
                    color: Colors.deepPurple,
                  ),
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}

class PhotoTimeline extends StatelessWidget {
  const PhotoTimeline({super.key});

  // 生成带日期的模拟照片数据
  Map<String, List<Map<String, dynamic>>> _groupPhotosByDate() {
    final random = Random();
    final now = DateTime.now();
    final photos = <Map<String, dynamic>>[];
    
    // 生成过去30天的模拟数据
    for (int i = 0; i < 30; i++) {
      final date = now.subtract(Duration(days: i));
      final photoCount = random.nextInt(5) + 1; // 每天1-5张照片
      
      for (int j = 0; j < photoCount; j++) {
        photos.add({
          'id': 'photo_${i}_$j',
          'title': '照片 ${i * 5 + j + 1}',
          'date': date,
        });
      }
    }
    
    // 按日期分组
    final grouped = <String, List<Map<String, dynamic>>>{};
    for (final photo in photos) {
      final date = photo['date'] as DateTime;
      final key = _formatDateKey(date);
      grouped.putIfAbsent(key, () => []).add(photo);
    }
    
    return grouped;
  }

  String _formatDateKey(DateTime date) {
    final now = DateTime.now();
    final today = DateTime(now.year, now.month, now.day);
    final yesterday = today.subtract(const Duration(days: 1));
    final dateDay = DateTime(date.year, date.month, date.day);
    
    if (dateDay == today) {
      return '今天';
    } else if (dateDay == yesterday) {
      return '昨天';
    } else if (date.year == now.year) {
      return '${date.month}月${date.day}日';
    } else {
      return '${date.year}年${date.month}月${date.day}日';
    }
  }

  @override
  Widget build(BuildContext context) {
    final groupedPhotos = _groupPhotosByDate();
    final sortedKeys = groupedPhotos.keys.toList()
      ..sort((a, b) {
        // 将中文日期转换为可排序的格式
        final dateA = _parseDateKey(a);
        final dateB = _parseDateKey(b);
        return dateB.compareTo(dateA); // 降序排列
      });

    return ListView.builder(
      padding: const EdgeInsets.only(top: 88, bottom: 16),
      itemCount: sortedKeys.length,
      itemBuilder: (context, index) {
        final dateKey = sortedKeys[index];
        final photos = groupedPhotos[dateKey]!;
        
        return Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Padding(
              padding: const EdgeInsets.fromLTRB(16, 16, 16, 8),
              child: Text(
                dateKey,
                style: const TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.bold,
                  color: Colors.deepPurple,
                ),
              ),
            ),
            GridView.builder(
              shrinkWrap: true,
              physics: const NeverScrollableScrollPhysics(),
              padding: const EdgeInsets.symmetric(horizontal: 16),
              gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
                crossAxisCount: 3,
                crossAxisSpacing: 4,
                mainAxisSpacing: 4,
                childAspectRatio: 1,
              ),
              itemCount: photos.length,
              itemBuilder: (context, photoIndex) {
                final photo = photos[photoIndex];
                return GestureDetector(
                  onTap: () {
                    Navigator.push(
                      context,
                      MaterialPageRoute(
                        builder: (context) => PhotoDetailPage(
                          photos: photos.map((p) => p['title'] as String).toList(),
                          initialIndex: photoIndex,
                        ),
                      ),
                    );
                  },
                  child: Container(
                    decoration: BoxDecoration(
                      color: Colors.grey[300],
                      borderRadius: BorderRadius.circular(8),
                    ),
                    child: Center(
                      child: Column(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: [
                          const Icon(Icons.photo, size: 40, color: Colors.grey),
                          const SizedBox(height: 4),
                          Text(
                            photo['title'] as String,
                            style: const TextStyle(fontSize: 12),
                            overflow: TextOverflow.ellipsis,
                          ),
                        ],
                      ),
                    ),
                  ),
                );
              },
            ),
          ],
        );
      },
    );
  }

  DateTime _parseDateKey(String key) {
    final now = DateTime.now();
    
    if (key == '今天') {
      return now;
    } else if (key == '昨天') {
      return now.subtract(const Duration(days: 1));
    } else if (key.contains('年')) {
      // 格式：2024年5月15日
      final match = RegExp(r'(\d+)年(\d+)月(\d+)日').firstMatch(key);
      if (match != null) {
        return DateTime(
          int.parse(match.group(1)!),
          int.parse(match.group(2)!),
          int.parse(match.group(3)!),
        );
      }
    } else {
      // 格式：5月15日
      final match = RegExp(r'(\d+)月(\d+)日').firstMatch(key);
      if (match != null) {
        return DateTime(
          now.year,
          int.parse(match.group(1)!),
          int.parse(match.group(2)!),
        );
      }
    }
    
    return now;
  }
}

class PhotoDetailPage extends StatefulWidget {
  final List<String> photos;
  final int initialIndex;

  const PhotoDetailPage({
    super.key,
    required this.photos,
    required this.initialIndex,
  });

  @override
  State<PhotoDetailPage> createState() => _PhotoDetailPageState();
}

class _PhotoDetailPageState extends State<PhotoDetailPage> {
  late int _currentIndex;
  late PageController _pageController;

  @override
  void initState() {
    super.initState();
    _currentIndex = widget.initialIndex;
    _pageController = PageController(initialPage: _currentIndex);
  }

  @override
  void dispose() {
    _pageController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.black,
      appBar: AppBar(
        backgroundColor: Colors.transparent,
        elevation: 0,
        actions: [
          IconButton(
            icon: const Icon(Icons.favorite_border),
            onPressed: () {
              // TODO: 实现收藏功能
              ScaffoldMessenger.of(context).showSnackBar(
                const SnackBar(content: Text('收藏功能待实现')),
              );
            },
          ),
          IconButton(
            icon: const Icon(Icons.share),
            onPressed: () {
              // TODO: 实现分享功能
              ScaffoldMessenger.of(context).showSnackBar(
                const SnackBar(content: Text('分享功能待实现')),
              );
            },
          ),
          IconButton(
            icon: const Icon(Icons.delete),
            onPressed: () {
              // TODO: 实现删除功能
              ScaffoldMessenger.of(context).showSnackBar(
                const SnackBar(content: Text('删除功能待实现')),
              );
            },
          ),
        ],
      ),
      body: Stack(
        children: [
          PageView.builder(
            controller: _pageController,
            itemCount: widget.photos.length,
            onPageChanged: (index) {
              setState(() {
                _currentIndex = index;
              });
            },
            itemBuilder: (context, index) {
              return Center(
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Container(
                      width: MediaQuery.of(context).size.width,
                      height: MediaQuery.of(context).size.height * 0.7,
                      color: Colors.grey[800],
                      child: Center(
                        child: Column(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: [
                            const Icon(Icons.photo, size: 100, color: Colors.white),
                            const SizedBox(height: 20),
                            Text(
                              widget.photos[index],
                              style: const TextStyle(
                                color: Colors.white,
                                fontSize: 24,
                              ),
                            ),
                          ],
                        ),
                      ),
                    ),
                  ],
                ),
              );
            },
          ),
          Positioned(
            bottom: 20,
            left: 0,
            right: 0,
            child: Center(
              child: Text(
                '${_currentIndex + 1} / ${widget.photos.length}',
                style: const TextStyle(
                  color: Colors.white,
                  fontSize: 16,
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}