app.py

import streamlit as st
import os
from langchain_community.vectorstores import Chroma
from langchain_community.embeddings import HuggingFaceBgeEmbeddings
from langchain_community.llms import Together
from langchain import hub
from operator import itemgetter
from langchain.chains import LLMChain
from langchain.chains import ConversationalRetrievalChain
from langchain.prompts import ChatPromptTemplate, MessagesPlaceholder, PromptTemplate
from langchain.memory import ConversationBufferMemory
from langchain_community.chat_message_histories import StreamlitChatMessageHistory
import time

# Load the embedding function
model_name = "BAAI/bge-base-en"
encode_kwargs = {'normalize_embeddings': True}

embedding_function = HuggingFaceBgeEmbeddings(
    model_name=model_name,
    encode_kwargs=encode_kwargs
)

# Load the LLM
llm = Together(
    model="mistralai/Mixtral-8x22B-Instruct-v0.1",
    temperature=0.2,
    max_tokens=19096,
    top_k=10,
    together_api_key=os.environ['pilotikval']
)

# Load the summarizeLLM
llmc = Together(
    model="mistralai/Mixtral-8x7B-Instruct-v0.1",
    temperature=0.2,
    max_tokens=1024,
    top_k=1,
    together_api_key=os.environ['pilotikval']
)

msgs = StreamlitChatMessageHistory(key="langchain_messages")
memory = ConversationBufferMemory(chat_memory=msgs, memory_key="chat_history", return_messages=True)

DEFAULT_DOCUMENT_PROMPT = PromptTemplate.from_template(template="{page_content}")

def _combine_documents(
        docs, document_prompt=DEFAULT_DOCUMENT_PROMPT, document_separator="\n\n"
    ):
    doc_strings = [format_document(doc, document_prompt) for doc in docs]
    return document_separator.join(doc_strings)

chistory = []

def store_chat_history(role: str, content: str):
    chistory.append({"role": role, "content": content})

def app():
    with st.sidebar:
        st.title("dochatter")
        option = st.selectbox(
            'Which retriever would you like to use?',
            ('General Medicine', 'RespiratoryFishman', 'RespiratoryMurray', 'MedMRCP2', 'OldMedicine')
        )
        if option == 'RespiratoryFishman':
            persist_directory = "./respfishmandbcud/"
            vectordb = Chroma(persist_directory=persist_directory, embedding_function=embedding_function, collection_name="fishmannotescud")
            retriever = vectordb.as_retriever(search_kwargs={"k": 5})
        elif option == 'RespiratoryMurray':
            persist_directory = "./respmurray/"
            vectordb = Chroma(persist_directory=persist_directory, embedding_function=embedding_function, collection_name="respmurraynotes")
            retriever = vectordb.as_retriever(search_kwargs={"k": 5})
        elif option == 'MedMRCP2':
            persist_directory = "./medmrcp2store/"
            vectordb = Chroma(persist_directory=persist_directory, embedding_function=embedding_function, collection_name="medmrcp2notes")
            retriever = vectordb.as_retriever(search_kwargs={"k": 5})
        elif option == 'General Medicine':
            persist_directory = "./oxfordmedbookdir/"
            vectordb = Chroma(persist_directory=persist_directory, embedding_function=embedding_function, collection_name="oxfordmed")
            retriever = vectordb.as_retriever(search_kwargs={"k": 7})
        else:
            persist_directory = "./mrcpchromadb/"
            vectordb = Chroma(persist_directory=persist_directory, embedding_function=embedding_function, collection_name="mrcppassmednotes")
            retriever = vectordb.as_retriever(search_kwargs={"k": 5})

    if "messages" not in st.session_state.keys():
        st.session_state.messages = [{"role": "assistant", "content": "How may I help you?"}]

    condense_template = """Given the following conversation and a follow-up question, rephrase the follow-up question to be a standalone question which contains the themes of the conversation.
    Chat History:
    {chat_history}
    Follow-Up Input: {question}
    Standalone question:"""
    CONDENSE_QUESTION_PROMPT = PromptTemplate.from_template(condense_template)

    answer_template = """You are helping a doctor. Answer with what you know from the context provided. Please be as detailed and thorough. Answer the question based on the following context:
    {context}
    Question: {question}"""
    ANSWER_PROMPT = ChatPromptTemplate.from_template(answer_template)

    conversational_qa_chain = ConversationalRetrievalChain(
        retriever=retriever,
        memory=memory,
        combine_docs_chain=_combine_documents,
        condense_question_chain=LLMChain(llm=llmc, prompt=CONDENSE_QUESTION_PROMPT),
        qa_chain=LLMChain(llm=llm, prompt=ANSWER_PROMPT)
    )

    st.header("Ask Away!")
    for message in st.session_state.messages:
        with st.chat_message(message["role"]):
            st.write(message["content"])
            store_chat_history(message["role"], message["content"])

    prompts2 = st.chat_input("Say something")

    if prompts2:
        st.session_state.messages.append({"role": "user", "content": prompts2})
        with st.chat_message("user"):
            st.write(prompts2)

    if st.session_state.messages[-1]["role"] != "assistant":
        with st.chat_message("assistant"):
            with st.spinner("Thinking..."):
                for _ in range(3):
                    try:
                        response = conversational_qa_chain.invoke(
                            {
                                "question": prompts2,
                                "chat_history": chistory,
                            }
                        )
                        st.write(response)
                        message = {"role": "assistant", "content": response}
                        st.session_state.messages.append(message)
                        break
                    except Exception as e:
                        st.error(f"An error occurred: {e}")
                        time.sleep(2)

if __name__ == '__main__':
    app()