fix: 修复下载器可靠性并简化标题与状态样式

Documentation/torrent-download.md

@@ -7,8 +7,9 @@ NipaPlay 的下载器可以管理种子文件和磁力链接任务，并在任
 1. 打开下载器，选择添加种子文件或磁力链接。
 2. 选择下载目录；移动设备需先确认系统存储权限。
 3. 如需按任务分类，启用“为任务创建目录”。
-4. 查看元数据和文件列表后开始任务；可暂停、继续或移除任务。
-5. 删除任务前确认是否同时删除本地数据。该操作可能不可恢复。
+4. 预览元数据和文件列表后添加任务；添加直接复用预览结果。解析最多等待 60 秒，可取消或修改链接后重试。
+5. 下载中可选择视频边下边播；初始化暂停后可继续，错误任务可重试，完成后的做种也可暂停。
+6. 删除任务前确认是否同时删除本地数据。该操作可能不可恢复。
 
 ## 使用建议
 
@@ -20,3 +21,10 @@ NipaPlay 的下载器可以管理种子文件和磁力链接任务，并在任
 ## 排障信息
 
 报告问题时附上任务状态、保存目录是否可写、可用磁盘空间、平台、NipaPlay 版本和脱敏日志；不要公开含有私人 tracker、token 或个人路径的 magnet/日志。
+
+## 任务状态与保存
+
+- 添加过程中显示处理提示；操作完成后立即刷新对应状态，其他任务仍可操作。
+- 重复添加会提示任务已存在，并保留原任务的状态和保存位置。继续下载请使用任务的继续或重试按钮。
+- Android 和鸿蒙将任务记录保存在应用支持目录，不随下载位置改变。升级时会从当前下载目录、最近使用的目录和默认下载目录导入旧记录；保留原文件、暂停状态和旧记录备份。
+- 自动入库只扫描该任务已经完成的视频文件。失败会重试，不会把共享下载目录中的其他未完成文件一并扫描。旧版本的扫描完成标记会重新验证一次。

lib/constants/settings_keys.dart

@@ -88,6 +88,7 @@ class SettingsKeys {
   static const String downloaderAutoScanCompletedTasks =
       'downloader_auto_scan_completed_tasks';
 
+  static const String downloaderVerifiedScannedCompletedTaskKeys = 'downloader_verified_scanned_completed_task_keys';
   static const String downloaderAutoScannedCompletedTaskKeys =
       'downloader_auto_scanned_completed_task_keys';
 

lib/downloads/torrent_task_controller.dart

@@ -0,0 +1,54 @@
+import 'package:flutter/foundation.dart';
+import 'package:nipaplay/models/torrent_task.dart';
+
+/// Serializes snapshots and locks individual tasks until their changed state has
+/// been read back. A slow add or another task never blocks list polling.
+class TorrentTaskController extends ChangeNotifier {
+  TorrentTaskController({required this.loadTasks});
+
+  final Future<List<TorrentTask>> Function() loadTasks;
+  List<TorrentTask> _tasks = const [];
+  List<TorrentTask> get tasks => _tasks;
+  final Set<int> _busyIds = {};
+  bool isBusy(int id) => _busyIds.contains(id);
+  Future<void>? _refresh;
+  bool _refreshAgain = false;
+  bool _disposed = false;
+
+  Future<void> refresh() {
+    if (_disposed) return Future<void>.value();
+    _refreshAgain = true;
+    return _refresh ??= _drainRefresh().whenComplete(() => _refresh = null);
+  }
+
+  Future<void> _drainRefresh() async {
+    do {
+      _refreshAgain = false;
+      final tasks = await loadTasks();
+      if (_disposed) return;
+      _tasks = List.unmodifiable(tasks);
+      notifyListeners();
+    } while (_refreshAgain);
+  }
+
+  Future<bool> run(int id, Future<void> Function() action) async {
+    if (_disposed || !_busyIds.add(id)) return false;
+    notifyListeners();
+    try {
+      await action();
+      // If a pre-action poll was already in flight, refresh() schedules another
+      // read before releasing this task's controls.
+      await refresh();
+      return true;
+    } finally {
+      _busyIds.remove(id);
+      if (!_disposed) notifyListeners();
+    }
+  }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
+}

lib/downloads/unified_torrent_page_model.dart

@@ -2,6 +2,7 @@ import 'package:nipaplay/models/torrent_task.dart';
 import 'package:nipaplay/models/torrent_task_scan_summary.dart';
 import 'package:flutter/widgets.dart';
 import 'package:nipaplay/models/torrent_magnet_preview.dart';
+import 'package:nipaplay/services/torrent_download_service.dart';
 
 enum UnifiedTorrentTaskViewMode { cards, list }
 
@@ -19,7 +20,7 @@ class UnifiedTorrentTaskActionViewModel {
 
   final UnifiedTorrentTaskAction action;
   final String label;
-  final VoidCallback onPressed;
+  final VoidCallback? onPressed;
   final bool destructive;
 }
 
@@ -47,9 +48,10 @@ class UnifiedTorrentTaskItemViewModel {
     return null;
   }
 
-  UnifiedTorrentTaskActionViewModel get primaryAction => task.finished
-      ? action(UnifiedTorrentTaskAction.play)!
-      : action(UnifiedTorrentTaskAction.toggle)!;
+  UnifiedTorrentTaskActionViewModel get primaryAction =>
+      task.finished && task.canPlay
+          ? action(UnifiedTorrentTaskAction.play)!
+          : action(UnifiedTorrentTaskAction.toggle)!;
 
   String? get scanStatusText {
     if (isAutoScanning) return '正在加入媒体库...';
@@ -134,8 +136,12 @@ class AddTorrentDialogResult {
     required this.magnetUri,
     required this.downloadDirectory,
     required this.createFolderForTask,
+    required this.preview,
+    required this.previewRequest,
   });
 
+  final TorrentPreviewRequest previewRequest;
+  final TorrentMagnetPreview preview;
   final String magnetUri;
   final String downloadDirectory;
   final bool createFolderForTask;

lib/models/torrent_add_result.dart

@@ -0,0 +1,24 @@
+import 'dart:convert';
+
+class TorrentAddResult {
+  const TorrentAddResult(
+      {required this.id,
+      required this.alreadyExists,
+      required this.outputFolder});
+
+  final int id;
+  final bool alreadyExists;
+  final String outputFolder;
+
+  factory TorrentAddResult.fromJson(String json) {
+    final data = jsonDecode(json) as Map<String, dynamic>;
+    return TorrentAddResult(
+      id: (data['id'] as num).toInt(),
+      alreadyExists: data['already_exists'] == true,
+      outputFolder: data['output_folder'] as String,
+    );
+  }
+
+  String get message =>
+      alreadyExists ? '任务已存在，保留原状态和保存位置：$outputFolder' : '已添加下载任务';
+}

lib/models/torrent_magnet_preview.dart

@@ -30,14 +30,16 @@ class TorrentMagnetPreview {
     required this.suggestedFolderName,
     required this.totalSize,
     required this.files,
+    this.requestId = 0,
   });
 
+  final int requestId;
   final String name;
   final String suggestedFolderName;
   final int totalSize;
   final List<TorrentMagnetPreviewFile> files;
 
-  factory TorrentMagnetPreview.fromJson(String jsonText) {
+  factory TorrentMagnetPreview.fromJson(String jsonText, {int requestId = 0}) {
     final decoded = jsonDecode(jsonText);
     if (decoded is! Map<String, dynamic>) {
       return const TorrentMagnetPreview(
@@ -50,6 +52,7 @@ class TorrentMagnetPreview {
 
     final rawFiles = decoded['files'];
     return TorrentMagnetPreview(
+      requestId: requestId,
       name: _asString(decoded['name'], fallback: '未命名任务'),
       suggestedFolderName: _asString(decoded['suggested_folder_name']),
       totalSize: _asInt(decoded['total_size']),

lib/models/torrent_task.dart

@@ -74,6 +74,7 @@ class TorrentTask {
     required this.uploadSpeedBytesPerSecond,
     required this.error,
     this.files = const <TorrentTaskFile>[],
+    this.initializingPaused = false,
   });
 
   final int id;
@@ -85,6 +86,7 @@ class TorrentTask {
   final int uploadedBytes;
   final int totalBytes;
   final bool finished;
+  final bool initializingPaused;
   final int downloadSpeedBytesPerSecond;
   final int uploadSpeedBytesPerSecond;
   final String? error;
@@ -95,17 +97,33 @@ class TorrentTask {
     return (progressBytes / totalBytes).clamp(0.0, 1.0);
   }
 
-  bool get isPaused => state == 'paused';
+  bool get isPaused =>
+      state == 'paused' || (state == 'initializing' && initializingPaused);
 
-  bool get isActive => state == 'live' || state == 'initializing';
+  bool get canResume => isPaused || hasError;
+
+  bool get canPlay => !hasError && state != 'initializing';
+
+  String get toggleLabel => hasError
+      ? '重试'
+      : isPaused
+          ? (finished ? '继续做种' : '继续下载')
+          : (finished ? '暂停做种' : '暂停下载');
+
+  bool get isActive =>
+      !finished &&
+      !isPaused &&
+      !hasError &&
+      (state == 'live' || state == 'initializing');
 
   bool get hasError => state == 'error' || (error?.isNotEmpty ?? false);
 
   String get autoScanKey => '$infoHash|$outputFolder';
 
   String get displayState {
     if (hasError) return '错误';
-    if (finished) return '已完成';
+    if (finished) return isPaused ? '已完成（已暂停）' : '已完成（做种中）';
+    if (isPaused) return '已暂停';
     switch (state) {
       case 'initializing':
         return '初始化';
@@ -136,6 +154,7 @@ class TorrentTask {
       uploadedBytes: _asInt(stats['uploaded_bytes']),
       totalBytes: _asInt(stats['total_bytes']),
       finished: stats['finished'] == true,
+      initializingPaused: stats['initializing_paused'] == true,
       downloadSpeedBytesPerSecond:
           _speedBytes(live['download_speed'] as Map<String, dynamic>?),
       uploadSpeedBytesPerSecond:
@@ -158,6 +177,7 @@ class TorrentTask {
       uploadedBytes: uploadedBytes,
       totalBytes: totalBytes,
       finished: finished,
+      initializingPaused: initializingPaused,
       downloadSpeedBytesPerSecond: downloadSpeedBytesPerSecond,
       uploadSpeedBytesPerSecond: uploadSpeedBytesPerSecond,
       error: error,