add chinese subtitles

sentence_api/main.py

@@ -45,6 +45,8 @@ from .models import (
     SentenceBoundaryDocument,
     SentenceExplanationRequest,
     SentenceExplanationResponse,
+    SubtitleTranslationItem,
+    SubtitleTranslationResponse,
     PasswordResetRequest,
     SentenceTextUpdate,
     UserDubShareSummary,
@@ -333,6 +335,60 @@ def create_app(
             raise HTTPException(status_code=503, detail=str(exc)) from exc
         return SentenceExplanationResponse(explanation=explanation)
 
+    @application.post(
+        "/api/v1/videos/{video_hash}/subtitle-translation",
+        response_model=SubtitleTranslationResponse,
+    )
+    def translate_subtitles(
+        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.")
+        payload = [
+            (sentence.index, sentence.text or "")
+            for sentence in document.sentences
+            if (sentence.text or "").strip()
+        ]
+        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()
+        ]
+        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,
+            )
+        video = video_repository.get_video(video_hash)
+        try:
+            translated = application.state.ai_tutor.translate_sentences(
+                payload,
+                course_title=(video["title"] if video is not None else "") or "",
+            )
+        except AITutorError as exc:
+            raise HTTPException(status_code=503, detail=str(exc)) from exc
+        saved = video_repository.save_sentence_translations(video_hash, translated)
+        if saved is None:
+            raise HTTPException(status_code=404, detail="Course is not available.")
+        return SubtitleTranslationResponse(
+            video_hash=saved.video_hash,
+            translations=[
+                SubtitleTranslationItem(index=sentence.index, zh_text=sentence.zh_text)
+                for sentence in saved.sentences
+                if sentence.zh_text and sentence.zh_text.strip()
+            ],
+        )
+
     @application.post(
         "/api/v1/audio/sentence-boundaries",
         response_model=SentenceBoundaryDocument,