fixed a bug:translate maybe timeout

sentence_api/main.py

@@ -335,6 +335,32 @@ def create_app(
             raise HTTPException(status_code=503, detail=str(exc)) from exc
         return SentenceExplanationResponse(explanation=explanation)
 
+    def stored_subtitle_translations(
+        document: SentenceBoundaryDocument,
+    ) -> SubtitleTranslationResponse:
+        return SubtitleTranslationResponse(
+            video_hash=document.video_hash,
+            translations=[
+                SubtitleTranslationItem(index=sentence.index, zh_text=sentence.zh_text)
+                for sentence in document.sentences
+                if sentence.zh_text and sentence.zh_text.strip()
+            ],
+        )
+
+    @application.get(
+        "/api/v1/videos/{video_hash}/subtitle-translation",
+        response_model=SubtitleTranslationResponse,
+    )
+    def get_subtitle_translation(
+        video_hash: str = SHA256_PATH,
+        user: AuthenticatedUser = Depends(current_user),
+    ) -> SubtitleTranslationResponse:
+        del user
+        document = video_repository.get_document(video_hash)
+        if document is None:
+            raise HTTPException(status_code=404, detail="Course is not available.")
+        return stored_subtitle_translations(document)
+
     @application.post(
         "/api/v1/videos/{video_hash}/subtitle-translation",
         response_model=SubtitleTranslationResponse,
@@ -354,26 +380,28 @@ def create_app(
         ]
         if not payload:
             raise HTTPException(status_code=422, detail="No sentence text is available to translate.")
-        cached = [
-            SubtitleTranslationItem(index=sentence.index, zh_text=sentence.zh_text)
-            for sentence in document.sentences
-            if sentence.zh_text and sentence.zh_text.strip()
-        ]
+        cached = stored_subtitle_translations(document).translations
         complete = len(cached) == len(payload) and all(
             (sentence.zh_text or "").strip()
             for sentence in document.sentences
             if (sentence.text or "").strip()
         )
         if complete:
-            return SubtitleTranslationResponse(
-                video_hash=document.video_hash,
-                translations=cached,
-            )
+            return stored_subtitle_translations(document)
         video = video_repository.get_video(video_hash)
+        existing = {
+            item.index: item.zh_text
+            for item in cached
+        }
         try:
             translated = application.state.ai_tutor.translate_sentences(
                 payload,
                 course_title=(video["title"] if video is not None else "") or "",
+                existing=existing,
+                persist=lambda part: video_repository.save_sentence_translations(
+                    video_hash,
+                    part,
+                ),
             )
         except AITutorError as exc:
             raise HTTPException(status_code=503, detail=str(exc)) from exc