Update config.py

config.py

@@ -4,28 +4,32 @@ from typing import List, Dict
 from openai import OpenAI
 from langchain_openai import ChatOpenAI, OpenAIEmbeddings
 
-llm_default = ChatOpenAI(
-    model=DEFAULT_MODEL,
-    temperature=0.5,
-    timeout=20,
-)
-
-embedding_client = OpenAIEmbeddings(model=EMBEDDING_MODEL)
-
-
-# ---------- 环境变量 & OpenAI Client ----------
+# ---------- 环境变量 & OpenAI API Key ----------
 OPENAI_API_KEY = os.getenv("OPENAI_API_KEY")
 if not OPENAI_API_KEY:
     raise RuntimeError(
         "OPENAI_API_KEY is not set. Please go to Settings → Secrets and add it."
     )
 
-client = OpenAI(api_key=OPENAI_API_KEY)
-
-# ---------- 模型配置 ----------
+# ---------- 模型配置（一定要在用之前定义） ----------
 DEFAULT_MODEL = "gpt-4.1-mini"
 EMBEDDING_MODEL = "text-embedding-3-small"
 
+# ---------- OpenAI 原生 Client（老代码还在用） ----------
+client = OpenAI(api_key=OPENAI_API_KEY)
+
+# ---------- LangChain 封装的 LLM & Embedding ----------
+# 以后如果你想用 LangChain 的 ChatOpenAI / OpenAIEmbeddings，可以直接用这两个
+llm_default = ChatOpenAI(
+    model=DEFAULT_MODEL,
+    temperature=0.5,
+    timeout=20,
+)
+
+embedding_client = OpenAIEmbeddings(
+    model=EMBEDDING_MODEL,
+)
+
 # ---------- 默认 GenAI 课程大纲 ----------
 DEFAULT_COURSE_TOPICS: List[str] = [
     "Week 0 – Welcome & What is Generative AI; course outcomes LO1–LO5.",