fix: auto-fix code issues (cron)

- 修复隐式 Optional 类型注解 (RUF013)
- 修复不必要的赋值后返回 (RET504)
- 优化列表推导式 (PERF401)
- 修复未使用的参数 (ARG002)
- 清理重复导入
- 优化异常处理

backend/multimodal_processor.py

@@ -74,7 +74,7 @@ class VideoInfo:
     transcript_id: str = ""
     status: str = "pending"
     error_message: str = ""
-    metadata: dict = None
+    metadata: dict | None = None
 
     def __post_init__(self) -> None:
         if self.metadata is None:
@@ -97,7 +97,7 @@ class VideoProcessingResult:
 class MultimodalProcessor:
     """多模态处理器 - 处理视频文件"""
 
-    def __init__(self, temp_dir: str = None, frame_interval: int = 5) -> None:
+    def __init__(self, temp_dir: str | None = None, frame_interval: int = 5) -> None:
         """
         初始化多模态处理器
 
@@ -130,10 +130,12 @@ class MultimodalProcessor:
             if FFMPEG_AVAILABLE:
                 probe = ffmpeg.probe(video_path)
                 video_stream = next(
-                    (s for s in probe["streams"] if s["codec_type"] == "video"), None,
+                    (s for s in probe["streams"] if s["codec_type"] == "video"),
+                    None,
                 )
                 audio_stream = next(
-                    (s for s in probe["streams"] if s["codec_type"] == "audio"), None,
+                    (s for s in probe["streams"] if s["codec_type"] == "audio"),
+                    None,
                 )
 
                 if video_stream:
@@ -165,9 +167,9 @@ class MultimodalProcessor:
                     return {
                         "duration": float(data["format"].get("duration", 0)),
                         "width": int(data["streams"][0].get("width", 0)) if data["streams"] else 0,
-                        "height": int(data["streams"][0].get("height", 0))
-                        if data["streams"]
-                        else 0,
+                        "height": (
+                            int(data["streams"][0].get("height", 0)) if data["streams"] else 0
+                        ),
                         "fps": 30.0,  # 默认值
                         "has_audio": len(data["streams"]) > 1,
                         "bitrate": int(data["format"].get("bit_rate", 0)),
@@ -177,7 +179,7 @@ class MultimodalProcessor:
 
         return {"duration": 0, "width": 0, "height": 0, "fps": 0, "has_audio": False, "bitrate": 0}
 
-    def extract_audio(self, video_path: str, output_path: str = None) -> str:
+    def extract_audio(self, video_path: str, output_path: str | None = None) -> str:
         """
         从视频中提取音频
 
@@ -223,7 +225,9 @@ class MultimodalProcessor:
             print(f"Error extracting audio: {e}")
             raise
 
-    def extract_keyframes(self, video_path: str, video_id: str, interval: int = None) -> list[str]:
+    def extract_keyframes(
+        self, video_path: str, video_id: str, interval: int | None = None
+    ) -> list[str]:
         """
         从视频中提取关键帧
 
@@ -260,7 +264,8 @@ class MultimodalProcessor:
                     if frame_number % frame_interval_frames == 0:
                         timestamp = frame_number / fps
                         frame_path = os.path.join(
-                            video_frames_dir, f"frame_{frame_number:06d}_{timestamp:.2f}.jpg",
+                            video_frames_dir,
+                            f"frame_{frame_number:06d}_{timestamp:.2f}.jpg",
                         )
                         cv2.imwrite(frame_path, frame)
                         frame_paths.append(frame_path)
@@ -333,7 +338,11 @@ class MultimodalProcessor:
             return "", 0.0
 
     def process_video(
-        self, video_data: bytes, filename: str, project_id: str, video_id: str = None,
+        self,
+        video_data: bytes,
+        filename: str,
+        project_id: str,
+        video_id: str | None = None,
     ) -> VideoProcessingResult:
         """
         处理视频文件：提取音频、关键帧、OCR
@@ -426,7 +435,7 @@ class MultimodalProcessor:
                 error_message=str(e),
             )
 
-    def cleanup(self, video_id: str = None) -> None:
+    def cleanup(self, video_id: str | None = None) -> None:
         """
         清理临时文件
 
@@ -457,7 +466,9 @@ class MultimodalProcessor:
 _multimodal_processor = None
 
 
-def get_multimodal_processor(temp_dir: str = None, frame_interval: int = 5) -> MultimodalProcessor:
+def get_multimodal_processor(
+    temp_dir: str | None = None, frame_interval: int = 5
+) -> MultimodalProcessor:
     """获取多模态处理器单例"""
     global _multimodal_processor
     if _multimodal_processor is None: