app.py

import os
from typing import List
from chainlit.types import AskFileResponse
from aimakerspace.text_utils import CharacterTextSplitter, TextFileLoader
from aimakerspace.openai_utils.prompts import (
    UserRolePrompt,
    SystemRolePrompt,
    AssistantRolePrompt,
)
# from aimakerspace.openai_utils.embedding import EmbeddingModel
# from aimakerspace.vectordatabase import VectorDatabase
from langchain_openai import ChatOpenAI
# from aimakerspace.openai_utils.chatmodel import ChatOpenAI
import chainlit as cl
from langchain_text_splitters import RecursiveCharacterTextSplitter
# from langchain_experimental.text_splitter import SemanticChunker
# from langchain_openai.embeddings import OpenAIEmbeddings
from sentence_transformers import SentenceTransformer
from langchain_huggingface import HuggingFaceEmbeddings
from langchain_community.vectorstores import FAISS
from langchain_openai.embeddings import OpenAIEmbeddings
from langchain_core.documents import Document
from dotenv import load_dotenv
# from langchain.chains import RetrievalQA

load_dotenv()

system_template = """\
Use the following context to answer a users question. If you cannot find the answer in the context, say you don't know the answer."""
system_role_prompt = SystemRolePrompt(system_template)

user_prompt_template = """\
Context:
{context}
Question:
{question}
"""
user_role_prompt = UserRolePrompt(user_prompt_template)

# class RetrievalAugmentedQAPipeline:
#     def __init__(self, llm: ChatOpenAI(), vector_db_retriever: VectorDatabase) -> None:
#         self.llm = llm
#         self.vector_db_retriever = vector_db_retriever

#     async def arun_pipeline(self, user_query: str):
#         context_list = self.vector_db_retriever.search_by_text(user_query, k=4)

#         context_prompt = ""
#         for context in context_list:
#             context_prompt += context[0] + "\n"

#         formatted_system_prompt = system_role_prompt.create_message()

#         formatted_user_prompt = user_role_prompt.create_message(question=user_query, context=context_prompt)

#         async def generate_response():
#             async for chunk in self.llm.astream([formatted_system_prompt, formatted_user_prompt]):
#                 yield chunk

#         return {"response": generate_response(), "context": context_list}

text_splitter = RecursiveCharacterTextSplitter()


def process_text_file(file: AskFileResponse):
    import tempfile
    from langchain_community.document_loaders.pdf import PyPDFLoader

    with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=file.name) as temp_file:
        temp_file_path = temp_file.name

    with open(temp_file_path, "wb") as f:
        f.write(file.content)

    if file.type == 'text/plain':
        text_loader = TextFileLoader(temp_file_path)
        documents = text_loader.load_documents()
    elif file.type == 'application/pdf':
        pdf_loader = PyPDFLoader(temp_file_path)
        documents = pdf_loader.load()
    else:
        raise ValueError("Provide a .txt or .pdf file")
    #texts = [x.page_content for x in text_splitter.transform_documents(documents)]
    # texts = [x.page_content for x in text_splitter.split_documents(documents)]
    return text_splitter.split_documents(documents)



@cl.on_chat_start
async def on_chat_start():
    files = None

    # Wait for the user to upload a file
    while files == None:
        files = await cl.AskFileMessage(
            content="Please upload a Text file or a PDF to begin!",
            accept=["text/plain", "application/pdf"],
            max_size_mb=12,
            timeout=180,
            max_files=10
        ).send()

    processed_documents = []
    for file in files:

        msg = cl.Message(
            content=f"Processing `{file.name}`...", disable_human_feedback=True
        )
        await msg.send()

        # load the file
        texts = process_text_file(file)
        processed_documents.extend(texts)
        print(f"Processing {len(texts)} text chunks")

        # Create a dict vector store
        # vector_db = VectorDatabase()
        # vector_db = await vector_db.abuild_from_list(texts)
        
    # chat_openai = ChatOpenAI()

    # Create a chain
    # retrieval_augmented_qa_pipeline = RetrievalAugmentedQAPipeline(
    #     vector_db_retriever=vector_db,
    #     llm=chat_openai
    # )
    
    # model = SentenceTransformer("acpotts/finetuned_arctic")
    
    finetune_embeddings = HuggingFaceEmbeddings(model_name='acpotts/finetuned_arctic')

    finetune_vectorstore = FAISS.from_documents(processed_documents, finetune_embeddings)
    finetune_retriever = finetune_vectorstore.as_retriever(search_kwargs={"k": 6})

    from operator import itemgetter
    from langchain_core.output_parsers import StrOutputParser
    from langchain_core.runnables import RunnablePassthrough, RunnableParallel

    rag_llm =  ChatOpenAI(
        model="gpt-4o-mini",
        temperature=0
        )
    

    finetune_rag_chain = (
        {"context": itemgetter("question") | finetune_retriever, "question": itemgetter("question")}
        | RunnablePassthrough.assign(context=itemgetter("context"))
        | {"response": system_template | rag_llm | StrOutputParser(), "context": itemgetter("context")}
    )

    
    # Let the user know that the system is ready
    msg.content = f"Processing `{file.name}` done. You can now ask questions!"
    await msg.update()

    cl.user_session.set("chain", finetune_rag_chain)


@cl.on_message
async def main(message):
    chain = cl.user_session.get("chain")

    msg = cl.Message(content="")
    # finetune_rag_chain.invoke({"question": message.content})
    # result = await chain.arun_pipeline(message.content)
    result = await chain.arun_pipeline({'question': message.content})

    async for stream_resp in result["response"]:
        await msg.stream_token(stream_resp)

    await msg.send()