refactor: make ASR client and video router provider-aware

Refactor ASRClient to delegate to provider (DashScopeASRProvider or OpenRouterASRProvider) via create_asr_provider() factory. transcribe_full() now async. Move _to_traditional to asr_providers.py (re-exported from asr_client.py for backward compat). Update video.py router to await transcribe_full() and validate API key per provider (DASHSCOPE_API_KEY for dashscope, OPENROUTER_API_KEY for openrouter).

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

backend/app/routers/video.py

@@ -94,14 +94,20 @@ async def transcribe_video(video_id: str, language: str = "yue"):
     from app.core.config import get_settings
     settings = get_settings()
 
-    if not settings.dashscope_api_key:
+    provider = settings.asr_provider
+    if provider == "dashscope" and not settings.dashscope_api_key:
         raise HTTPException(
             status_code=500,
             detail="DASHSCOPE_API_KEY is not configured. Set it in .env to enable transcription.",
         )
+    if provider == "openrouter" and not settings.openrouter_api_key:
+        raise HTTPException(
+            status_code=500,
+            detail="OPENROUTER_API_KEY is not configured. Set it in .env to enable OpenRouter ASR.",
+        )
 
     transcribe_start = time.monotonic()
-    logger.info("transcribe-started video_id=%s language=%s", video_id, language)
+    logger.info("transcribe-started video_id=%s language=%s provider=%s", video_id, language, provider)
 
     service = _get_video_service()
     wav_path = await service.extract_audio(video_id)
@@ -110,7 +116,7 @@ async def transcribe_video(video_id: str, language: str = "yue"):
         audio_bytes = wav_path.read_bytes()
         logger.debug("audio-extracted video_id=%s wav_size=%d", video_id, len(audio_bytes))
         asr = ASRClient(settings)
-        text = asr.transcribe_full(audio_bytes, language=language)
+        text = await asr.transcribe_full(audio_bytes, language=language)
     except Exception as e:
         logger.error("transcribe-failed video_id=%s error=%s", video_id, e)
         raise HTTPException(status_code=500, detail=f"Transcription failed: {str(e)}")

backend/app/services/asr_client.py

@@ -1,9 +1,8 @@
 import struct
-import base64
 import logging
+from typing import Any
 
-import zhconv
+from app.services.asr_providers import create_asr_provider, ASRError, _to_traditional  # noqa: F401
-from openai import OpenAI
 
 logger = logging.getLogger(__name__)
 
@@ -20,40 +19,16 @@ def build_display_text(accumulated: str, current: str) -> str:
     return " ".join(parts)
 
 
-def _to_traditional(text: str) -> str:
-    if not text:
-        return text
-    return zhconv.convert(text, "zh-hant")
-
-
 class ASRClient:
-    def __init__(self, settings):
+    def __init__(self, settings: Any):
-        self.settings = settings
+        self._settings = settings
+        self._provider = create_asr_provider(settings)
 
-    def transcribe_full(self, audio_bytes: bytes, language: str = "yue") -> str:
+    async def transcribe_full(self, audio_bytes: bytes, language: str = "yue") -> str:
-        audio_b64 = base64.b64encode(audio_bytes).decode()
+        try:
-        data_url = f"data:audio/wav;base64,{audio_b64}"
+            return await self._provider.transcribe(audio_bytes, language)
-
+        except ASRError:
-        client = OpenAI(
+            raise
-            api_key=self.settings.dashscope_api_key,
+        except Exception as e:
-            base_url="https://dashscope-intl.aliyuncs.com/compatible-mode/v1",
+            logger.error("transcribe_full failed: %s", e)
-        )
+            raise ASRError(f"Transcription failed: {e}") from e
-
-        asr_options: dict = {}
-        if language != "auto":
-            asr_options["language"] = language
-
-        resp = client.chat.completions.create(
-            model=self.settings.asr_model_name,
-            messages=[{  # type: ignore[list-item]
-                "role": "user",
-                "content": [{
-                    "type": "input_audio",
-                    "input_audio": {"data": data_url},
-                }],
-            }],
-            extra_body={"asr_options": asr_options} if asr_options else None,
-        )
-
-        result = resp.choices[0].message.content or ""
-        return _to_traditional(result)