SCR_Course_ChatBot / scripts /router_chain.py
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Update scripts/router_chain.py
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from typing import Dict, Any
from langchain_openai import ChatOpenAI
from langchain.prompts import ChatPromptTemplate
from langchain.schema import StrOutputParser
from scripts.rag_chat import build_general_qa_chain
def build_router_chain(model_name=None):
general_qa = build_general_qa_chain(model_name=model_name)
llm = ChatOpenAI(model_name=model_name or "gpt-4o-mini", temperature=0.0)
# This prompt asks the LLM to choose which "mode" to use
router_prompt = ChatPromptTemplate.from_template("""
You are a routing assistant for a chatbot.
Classify the following user request into one of these categories:
- "code" for programming or debugging
- "summarize" for summary requests
- "calculate" for math or numeric calculations
- "general" for general Q&A using course files
Return ONLY the category word.
User request: {input}
""")
router_chain = router_prompt | llm | StrOutputParser()
class Router:
def invoke(self, input_dict: Dict[str, Any]):
category = router_chain.invoke({"input": input_dict["input"]}).strip().lower()
print(f"[ROUTER] User query routed to category: {category}")
if category == "code":
prompt = ChatPromptTemplate.from_template(
"As a coding assistant, help with this Python question.\nQuestion: {input}\nAnswer:"
)
chain = prompt | llm | StrOutputParser()
return {"result": chain.invoke({"input": input_dict["input"]})}
# elif category == "summarize":
# prompt = ChatPromptTemplate.from_template(
# "Provide a concise summary about: {input}\nSummary:"
# )
# chain = prompt | llm | StrOutputParser()
# return {"result": chain.invoke({"input": input_dict["input"]})}
#elif category == "summarize":
# # 1. Use RAG to retrieve relevant docs
# rag_result = general_qa({"query": input_dict["input"]})
# # 2. Extract docs and prepare text
# source_docs = rag_result.get("source_documents", [])
# combined_text = "\n\n".join([doc.page_content for doc in source_docs])
# # 3. Run the summarizer chain on the retrieved text
# from scripts.summarizer import get_summarizer
# summarizer_chain = get_summarizer()
# summary = summarizer_chain.run(combined_text)
# # 4. Add sources if any
# sources = list({str(doc.metadata.get("source", "unknown")) for doc in source_docs})
# if sources:
# summary += f"\n\n📚 Sources: {', '.join(sources)}"
# return {"result": summary}
elif category == "summarize":
# 1) Retrieve relevant documents via your existing RAG chain
rag_result = general_qa({"query": input_dict["input"]})
# 2) Get the retrieved docs (already LangChain Document objects)
source_docs = rag_result.get("source_documents", []) or []
# 3) Build the summarizer and prepare the docs list
from langchain.docstore.document import Document
from scripts.summarizer import get_summarizer
summarizer_chain = get_summarizer()
# If retrieval returned nothing, fall back to summarizing the user’s text
docs = source_docs if source_docs else [Document(page_content=input_dict["input"])]
# 4) Summarize — load_summarize_chain returns {"output_text": "..."}
out = summarizer_chain.invoke(docs)
summary = out["output_text"] if isinstance(out, dict) and "output_text" in out else str(out)
# 5) Append sources (only if we actually had retrieved docs)
if source_docs:
sources = sorted({str(d.metadata.get("source", "unknown")) for d in source_docs})
if sources:
summary += f"\n\n📚 Sources: {', '.join(sources)}"
return {"result": summary}
elif category == "calculate":
prompt = ChatPromptTemplate.from_template(
"Solve the following calculation step-by-step:\n{input}"
)
chain = prompt | llm | StrOutputParser()
return {"result": chain.invoke({"input": input_dict["input"]})}
else: # "general"
return general_qa({"query": input_dict["input"]})
return Router()