getCachedMetaDataStatus method

Future<CacheStatusEnum> getCachedMetaDataStatus(String classId)

根据本地缓存文件判定当前缓存状态。 success.json 校验失败时先尝试按课程目录修复路径；仅当磁盘上已无核心视频时才删除 manifest，避免直连 Flutter/iOS 误判导致「缓存丢失」。

Implementation

Future<CacheStatusEnum> getCachedMetaDataStatus(String classId) async {
  classId = _trimClassId(classId);
  if (classId.isEmpty) return CacheStatusEnum.notCached;
  final cacheDir = await _ensureCacheDir();
  final safeId = _safeId(classId);
  final successPath = p.join(cacheDir.path, '$safeId-success.json');
  final successFile = File(successPath);

  if (await successFile.exists()) {
    var valid = await _validateSuccessJsonFiles(successFile);
    if (!valid) {
      await _repairSuccessJsonFromClassDir(safeId, successFile);
      valid = await _validateSuccessJsonFiles(successFile);
    }
    if (!valid) {
      valid = await _validateSuccessCoreVideosOnly(successFile);
    }
    if (!valid) {
      if (!await _classCoreVideosExist(safeId)) {
        try {
          await successFile.delete();
        } catch (_) {}
      }
      return CacheStatusEnum.notCached;
    }
    return CacheStatusEnum.cachedSuccess;
  }
  // 优先于 failed.json：重试下载时会先写入 meta，避免仍显示「缓存失败」
  final metaPath = p.join(cacheDir.path, '$safeId.json');
  if (await File(metaPath).exists()) {
    if (_downloadingClassIds.contains(classId)) {
      return CacheStatusEnum.caching;
    }
    if (_pausedClassIds.contains(classId)) {
      return CacheStatusEnum.cachePaused;
    }
    return CacheStatusEnum.cacheInterrupted;
  }
  if (await File(p.join(cacheDir.path, '$safeId-failed.json')).exists()) {
    return CacheStatusEnum.cachedFailed;
  }
  return CacheStatusEnum.notCached;
}