main.py

import os
import re
import openai
import streamlit as st
from langchain.chat_models import ChatOpenAI
from langchain.chains import RetrievalQAWithSourcesChain
from langchain.embeddings.openai import OpenAIEmbeddings
from langchain.vectorstores import FAISS

# Set OpenAI Model and API key
openai.api_key = st.secrets["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"]
model = "gpt-4" # Replace with the version of the api you have access

html_temp = """
                <div style="background-color:{};padding:1px">
                
                </div>
                """

st.set_page_config(page_title="Chat with Simon Wardley's Book")
st.title("Chat with Simon Wardley's Book")
st.sidebar.markdown("# Query this book using AI")
st.sidebar.markdown(html_temp.format("rgba(55, 53, 47, 0.16)"),unsafe_allow_html=True)
st.sidebar.markdown("Developed by Mark Craddock](https://twitter.com/mcraddock)", unsafe_allow_html=True)
st.sidebar.markdown("Current Version: 0.1.4")
st.sidebar.markdown(html_temp.format("rgba(55, 53, 47, 0.16)"),unsafe_allow_html=True)
st.sidebar.markdown("Using GPT-4 API")
st.sidebar.markdown("Not optimised")
st.sidebar.markdown("May run out of OpenAI credits")
st.sidebar.markdown(html_temp.format("rgba(55, 53, 47, 0.16)"),unsafe_allow_html=True)
st.sidebar.markdown("Wardley Mapping is provided courtesy of Simon Wardley and licensed Creative Commons Attribution Share-Alike.")

# Get datastore
DATA_STORE_DIR = "data_store"

if os.path.exists(DATA_STORE_DIR):
  #st.write("Loading database")
  vector_store = FAISS.load_local(
      DATA_STORE_DIR,
      OpenAIEmbeddings()
  )
else:
  st.write(f"Missing files. Upload index.faiss and index.pkl files to {DATA_STORE_DIR} directory first")
  
from langchain.prompts.chat import (
    ChatPromptTemplate,
    SystemMessagePromptTemplate,
    HumanMessagePromptTemplate,
)

system_template="""Use the following pieces of context to answer the users question.
Take note of the sources and include them in the answer in the format: "SOURCES: source1 source2", use "SOURCES" in capital letters regardless of the number of sources.
If you don't know the answer, just say that "I don't know", don't try to make up an answer.
----------------
{summaries}"""
messages = [
    SystemMessagePromptTemplate.from_template(system_template),
    HumanMessagePromptTemplate.from_template("{question}")
    ]
prompt = ChatPromptTemplate.from_messages(messages)

chain_type_kwargs = {"prompt": prompt}
llm = ChatOpenAI(model_name=model, temperature=0, max_tokens=256)  # Modify model_name if you have access to GPT-4
chain = RetrievalQAWithSourcesChain.from_chain_type(
    llm=llm,
    chain_type="stuff",
    retriever=vector_store.as_retriever(),
    return_source_documents=True,
    chain_type_kwargs=chain_type_kwargs
)

with st.spinner("Thinking..."):
    query = st.text_input("Question for the book?", value="What questions can I ask about this book?")
    result = chain(query)
    
st.write("### Answer:")
st.write(result['answer'])