refactor: centralize llm provider transport

app/backend/features/heaven/agent.py

@@ -1,11 +1,10 @@
 from __future__ import annotations
 
 import json
-import time
-import urllib.error
-import urllib.request
 from typing import Any
 
+from backend.llm import transport as llm_transport
+
 
 class HeavenAgentError(RuntimeError):
     pass
@@ -24,45 +23,33 @@ def interpret_heaven(
     if not api_key or not model:
         raise HeavenAgentError("LLM API Key 或模型尚未配置。")
     system_prompt = _system_prompt(mode)
-    payload = json.dumps(
+    messages = [
+        {"role": "system", "content": system_prompt},
         {
-            "model": model,
-            "messages": [
-                {"role": "system", "content": system_prompt},
-                {
-                    "role": "user",
-                    "content": json.dumps(context, ensure_ascii=False, separators=(",", ":")),
-                },
-            ],
-            "stream": False,
+            "role": "user",
+            "content": json.dumps(context, ensure_ascii=False, separators=(",", ":")),
         },
-        ensure_ascii=False,
-    ).encode("utf-8")
-    request = urllib.request.Request(
-        f"{base_url.rstrip('/')}/chat/completions",
-        data=payload,
-        headers={
-            "Content-Type": "application/json",
-            "Authorization": f"Bearer {api_key}",
-            "User-Agent": "XiaobaiReviewWeb/0.7",
-        },
-        method="POST",
-    )
-    started = time.perf_counter()
+    ]
     try:
-        with urllib.request.urlopen(request, timeout=timeout) as response:
-            result = json.loads(response.read().decode("utf-8"))
-        answer = str(result["choices"][0]["message"]["content"]).strip()
+        result = llm_transport.chat_completion(
+            api_key=api_key,
+            base_url=base_url,
+            model=model,
+            messages=messages,
+            timeout=timeout,
+            user_agent="XiaobaiReviewWeb/0.7",
+        )
+        answer = str(result.content).strip()
         if not answer:
             raise KeyError("empty response")
-    except urllib.error.HTTPError as exc:
-        raise HeavenAgentError(_http_error_message(exc)) from exc
-    except (urllib.error.URLError, TimeoutError, json.JSONDecodeError, KeyError, IndexError) as exc:
+    except llm_transport.OpenAIHTTPError as exc:
+        raise HeavenAgentError(exc.describe("问天模型调用失败")) from exc
+    except (llm_transport.OpenAITransportError, KeyError) as exc:
         raise HeavenAgentError(f"问天模型调用失败：{exc}") from exc
     return {
         "answer": answer,
         "model": model,
-        "latency_ms": round((time.perf_counter() - started) * 1000),
+        "latency_ms": result.latency_ms,
     }
 
 
@@ -99,20 +86,3 @@ def _system_prompt(mode: str) -> str:
 全文控制在180至350个中文字符。只写一句卦意；一小段动爻与之卦；最后三句极短的问心句。
 不要重述六条爻辞，不猜用户未说出口的问题，不以吉凶二字替代思考，不给出股票涨跌预测。语气安静、克制，越短越有余味。
 """.strip()
-
-
-def _http_error_message(exc: urllib.error.HTTPError) -> str:
-    detail = ""
-    try:
-        payload = json.loads(exc.read().decode("utf-8", errors="replace"))
-        error = payload.get("error")
-        if isinstance(error, dict):
-            detail = str(error.get("message") or error.get("code") or "")
-        elif error:
-            detail = str(error)
-        elif payload.get("message"):
-            detail = str(payload["message"])
-    except (json.JSONDecodeError, OSError):
-        detail = ""
-    suffix = f"：{detail[:300]}" if detail else ""
-    return f"问天模型调用失败（HTTP {exc.code}）{suffix}"