ios fixed

ios/OralTrainer/Models/PlaybackModels.swift

@@ -63,3 +63,22 @@ enum BoundaryState: Equatable {
     case loaded(count: Int)
     case failed(message: String)
 }
+
+/// 云端视频必须先完成整文件下载；下载未完成前不允许创建可播放的 AVPlayerItem。
+enum VideoCacheState: Equatable {
+    case notRequired
+    case downloading
+    case ready
+    case failed(message: String)
+
+    var statusMessage: String? {
+        switch self {
+        case .notRequired, .ready:
+            return nil
+        case .downloading:
+            return "正在下载完整视频，下载完成后才能播放"
+        case .failed(let message):
+            return "视频缓存失败：\(message)"
+        }
+    }
+}