app.py

import asyncio
import logging
from dotenv import load_dotenv
from pathlib import Path
from ingest_data import download_data_and_create_embedding
# from ingest_data import run_rag

from langchain_community.vectorstores import FAISS
from langchain_core.runnables.passthrough import RunnablePassthrough
from langchain_core.output_parsers import StrOutputParser
from langchain_core.prompts import ChatPromptTemplate
from langchain_openai import ChatOpenAI
from ingest_data import underlying_embeddings, openai_api_key

from langchain.chat_models import ChatOpenAI
from langchain.prompts import ChatPromptTemplate
from langchain.schema import StrOutputParser


import chainlit as cl

# load env variables
# load_dotenv()

# # Asynchronous execution (e.g., for a better a chatbot user experience)
# async def call_chain_async(question):
#     print("invoke the runnable chain")
#     output_chunks = await runnable_chain.ainvoke(question)
#     return output_chunks
    
# Specify the path to the file you want to check
# file_path = Path('./faiss_index/index.faiss')

# # Check if the file exists
# if file_path.exists():
#     print("Embeddings already done, use the saved index")
#     # Combine the retrieved data with the output of the LLM
#     vector_store = FAISS.load_local(
#         "faiss_index", underlying_embeddings, allow_dangerous_deserialization=True
#     )
# else:
#     vector_store = download_data_and_create_embedding()


# @cl.on_chat_start
# async def on_chat_start():
#     model = ChatOpenAI(streaming=True)
#     prompt = ChatPromptTemplate.from_messages(
#         [
#             (
#                 "system",
#                 "You're a very knowledgeable historian who provides accurate and eloquent answers to historical questions.",
#             ),
#             ("human", "{question}"),
#         ]
#     )
#     runnable = prompt | model | StrOutputParser()
#     cl.user_session.set("runnable", runnable)

# @cl.on_message
# async def on_message(message: cl.Message):
#     runnable = cl.user_session.get("runnable")  # type: Runnable

#     msg = cl.Message(content="")

#     async for chunk in runnable.astream(
#         {"question": message.content},
#         config=RunnableConfig(callbacks=[cl.LangchainCallbackHandler()]),
#     ):
#         await msg.stream_token(chunk)

#     await msg.send() 

# @cl.on_message
# async def main(question):
#     response = await call_chain_async(question.content)
#     await cl.Message(content=response).send()

@cl.on_chat_start
async def on_chat_start():
    msg=cl.Message(content="Firing up the movie info chatbot...")
    await msg.send()
    msg.content= "Hi, welcome to movie info chatbot. What is your query?"
    await msg.update()


@cl.on_message
async def on_message(message: cl.Message):
    print("Embeddings already done, use the saved index")
    # Combine the retrieved data with the output of the LLM
    vector_store = FAISS.load_local(
        "faiss_index", underlying_embeddings, allow_dangerous_deserialization=True
    )
    
    
    # create a prompt template to send to our LLM that will incorporate the documents from our retriever with the
    # question we ask the chat model
    print("Creating Prompt Template...")
    prompt_template = ChatPromptTemplate.from_template(
        "Answer the {question} based on the following {context}."
    )
    
    # create a retriever for our documents
    print("initializing retriever...")
    retriever = vector_store.as_retriever()
    
    # create a chat model / LLM
    print("initializing LLM...")
    chat_model = ChatOpenAI(
        model="gpt-3.5-turbo", temperature=0, api_key=openai_api_key
    )
    
    # create a parser to parse the output of our LLM
    print("initializing str output parser...")
    parser = StrOutputParser()
    
    # 💻 Create the sequence (recipe)
    print("initializing runnable chain...")
    runnable_chain = (
        # TODO: How do we chain the output of our retriever, prompt, model and model output parser so that we can get a good answer to our query?
        {"context": retriever, "question": RunnablePassthrough()}
        | prompt_template
        | chat_model
        | StrOutputParser()
    )
    
    print("Answer the following Question:")
    print(message.content)
    # Asynchronous execution (e.g., for a better a chatbot user experience)
    output_chunks = runnable_chain.invoke(message.content)
    # output_chunks = await runnable_chain.ainvoke(cl.Message.content)
    answer = ''.join(output_chunks)
    print(f"answer to question is : {answer}")

    # output_stream =  asyncio.run(call_chain_async("What are some good sci-fi movies from the 1980s?"))
    # print("".join(output_stream))

    # answer = await call_chain_async(question.content)
    await cl.Message(content=answer).send()