chatbot/core.py

from chatbot.llm import gemini_llm  # Import Gemini LLM
from chatbot.memory import memory
from chatbot.prompts import chat_prompt
from langchain.retrievers import WikipediaRetriever
from langchain.chains import ConversationalRetrievalChain
from pydantic import Field
from typing import List, Callable
from langchain.schema import BaseRetriever, Document

def translate_to_english(text: str) -> str:
    """Use Gemini LLM to translate text to English."""
    prompt = f"Translate the following text to English:\n\n{text}"
    response = gemini_llm.invoke(prompt)  # Invoke Gemini for translation
    return response  # Assuming `gemini_llm.invoke()` returns plain text

class WikipediaTranslationRetriever(BaseRetriever):
    retriever: WikipediaRetriever = Field(..., description="The underlying Wikipedia retriever")
    translator: Callable[[str], str] = Field(..., description="Function to translate queries to English")

    def get_relevant_documents(self, query: str) -> List[Document]:
        translated_query = self.translator(query)
        print(f"🔄 Translated Query: {translated_query}")
        return self.retriever.get_relevant_documents(translated_query)
    
    async def aget_relevant_documents(self, query: str) -> List[Document]:
        # For simplicity, we are not implementing the async version.
        raise NotImplementedError("Async retrieval is not implemented.")


# Create the retriever instance to be used in your qa_chain:
retriever = WikipediaTranslationRetriever(
    retriever=WikipediaRetriever(),
    translator=translate_to_english
)


# ✅ Use ConversationalRetrievalChain
qa_chain = ConversationalRetrievalChain.from_llm(
    llm=gemini_llm, 
    retriever=retriever, 
    memory=memory,  
    return_source_documents=False,  
    combine_docs_chain_kwargs={"prompt": chat_prompt},
    output_key="result"
)

def get_chat_response(user_input: str) -> str:
    """Process user input and return chat response using Wikipedia retrieval."""
    response = qa_chain(user_input)  # Pass query to retrieval-based QA chain

    # Save conversation context
    memory.save_context({"input": user_input}, {"output": response["result"]})

    return response["result"]