feat: add POST /tts/preview endpoint for synchronous TTS preview (#1496)

Co-authored-by: xiaoxia <dev@xiaoxiajianji.com>
Co-committed-by: xiaoxia <dev@xiaoxiajianji.com>

apps/api/app/api/routes/tts.py

@@ -20,6 +20,8 @@ from app.schemas.tts import (
     SaveToLibraryRequest,
     SaveToLibraryResponse,
     TTSJobResponse,
+    TTSPreviewRequest,
+    TTSPreviewResponse,
     TTSStatusResponse,
     TTSSynthesizeRequest,
     TTSSynthesizeResponse,
@@ -31,7 +33,7 @@ from packages.adapters.sqlalchemy_impl.tts_job_repository import (
     SQLAlchemyTTSJobRepository,
 )
 from packages.adapters.sqlalchemy_impl.voice_library_repository import SQLAlchemyVoiceLibraryRepository
-from packages.application.cosyvoice_service import CosyVoiceService
+from packages.application.cosyvoice_service import CosyVoiceError, CosyVoiceService
 from packages.application.tts_job.streaming_service import TTSStreamingService
 from packages.application.tts_job.use_cases import (
     CreateTTSJobUseCase,
@@ -373,6 +375,40 @@ def save_tts_job_to_library(
     )
 
 
+
+@router.post("/preview", response_model=TTSPreviewResponse)
+def preview_tts(
+    request: TTSPreviewRequest,
+    authenticated_user: AuthenticatedUser = Depends(get_current_user),
+    cosyvoice_service: CosyVoiceService = Depends(get_cosyvoice_service),
+) -> TTSPreviewResponse:
+    """TTS 预览（试听）——同步合成，立即返回音频 URL。
+
+    用于前端预览配音效果，限制文本长度 200 字以内。
+    """
+    try:
+        result = cosyvoice_service.synthesize_speech(
+            text=request.text,
+            voice_id=request.voice_id,
+            speed=request.speed,
+        )
+    except CosyVoiceError as e:
+        raise HTTPException(
+            status_code=status.HTTP_502_BAD_GATEWAY,
+            detail=f"TTS 合成失败: {e}",
+        ) from e
+    except ValueError as e:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=str(e),
+        ) from e
+
+    return TTSPreviewResponse(
+        audio_url=result.audio_url,
+        duration=result.duration if result.duration and result.duration > 0 else None,
+    )
+
+
 @router.websocket("/ws/tts/stream")
 async def tts_websocket_stream(
     websocket: WebSocket,