import 'package:cached_network_image/cached_network_image.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../core/media/download_manager.dart';
import '../../core/theme/app_theme.dart';
import '../../models/video_item.dart';

/// 已下载视频列表（我的 → 已下载）：
/// 下载中任务（进度/取消）+ 已完成列表（点击播放 / 左滑或长按删除）
class DownloadsScreen extends ConsumerWidget {
  const DownloadsScreen({super.key});

  static String _fmtSize(int bytes) {
    if (bytes >= 1 << 30) return '${(bytes / (1 << 30)).toStringAsFixed(2)} GB';
    if (bytes >= 1 << 20) return '${(bytes / (1 << 20)).toStringAsFixed(1)} MB';
    return '${(bytes / 1024).toStringAsFixed(0)} KB';
  }

  static String _fmtDuration(int seconds) {
    final m = seconds ~/ 60;
    final s = seconds % 60;
    return '$m:${s.toString().padLeft(2, '0')}';
  }

  void _play(BuildContext context, DownloadItem item) {
    context.push('/player',
        extra: VideoItem(
          videoId: item.videoId,
          title: item.title,
          coverUrl: item.coverUrl,
          videoUrl: item.playUrl,
          duration: item.duration,
          author: VideoAuthor(userId: 0),
        ));
  }

  Future<void> _confirmDelete(
      BuildContext context, WidgetRef ref, DownloadItem item) async {
    final ok = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('删除下载'),
        content: Text('删除「${item.title}」？'),
        actions: [
          TextButton(
              onPressed: () => Navigator.pop(ctx, false),
              child: const Text('取消')),
          TextButton(
              onPressed: () => Navigator.pop(ctx, true),
              child: const Text('删除', style: TextStyle(color: Colors.red))),
        ],
      ),
    );
    if (ok == true) {
      ref.read(downloadManagerProvider.notifier).delete(item.videoId);
    }
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final state = ref.watch(downloadManagerProvider);
    final downloading = state.progress.entries.toList();

    return Scaffold(
      appBar: AppBar(title: const Text('已下载')),
      body: ListView(
        children: [
          // 下载中
          for (final e in downloading)
            ListTile(
              leading: const SizedBox(
                width: 56, height: 56,
                child: Center(child: CircularProgressIndicator(strokeWidth: 2)),
              ),
              title: Text('视频 #${e.key}',
                  maxLines: 1, overflow: TextOverflow.ellipsis),
              subtitle: Padding(
                padding: const EdgeInsets.only(top: 6),
                child: LinearProgressIndicator(value: e.value),
              ),
              trailing: Text('${(e.value * 100).toStringAsFixed(0)}%'),
              onLongPress: () =>
                  ref.read(downloadManagerProvider.notifier).cancel(e.key),
            ),

          if (downloading.isNotEmpty) const Divider(),

          // 已完成
          if (state.items.isEmpty && downloading.isEmpty)
            const Padding(
              padding: EdgeInsets.only(top: 120),
              child: Center(
                child: Text('暂无下载\n长按视频可下载',
                    textAlign: TextAlign.center,
                    style: TextStyle(color: AppColors.textWeak)),
              ),
            ),
          for (final item in state.items)
            ListTile(
              contentPadding:
                  const EdgeInsets.symmetric(horizontal: 16, vertical: 6),
              leading: ClipRRect(
                borderRadius: BorderRadius.circular(6),
                child: SizedBox(
                  width: 72, height: 48,
                  child: item.coverUrl.isNotEmpty
                      ? CachedNetworkImage(
                          imageUrl: item.coverUrl, fit: BoxFit.cover)
                      : Container(
                          color: Colors.grey[800],
                          child: const Icon(Icons.play_circle_outline,
                              color: Colors.white54),
                        ),
                ),
              ),
              title: Text(item.title.isEmpty ? '视频 #${item.videoId}' : item.title,
                  maxLines: 1, overflow: TextOverflow.ellipsis),
              subtitle: Text(
                '${_fmtDuration(item.duration)} · ${_fmtSize(item.sizeBytes)}',
                style: const TextStyle(fontSize: 12),
              ),
              trailing: IconButton(
                icon: const Icon(Icons.delete_outline,
                    color: AppColors.textWeak),
                onPressed: () => _confirmDelete(context, ref, item),
              ),
              onTap: () => _play(context, item),
            ),
        ],
      ),
    );
  }
}