app.py

import logging
from concurrent.futures import ThreadPoolExecutor

import openai
import streamlit as st
from langchain_core.messages import AIMessage, ChatMessage, HumanMessage

from rag.runnable import get_runnable
from utils.error_message_template import ERROR_MESSAGE

logging.basicConfig(level=logging.ERROR)

# Streamlit page configuration
st.set_page_config(
    page_title="ELLA AI Assistant",
    page_icon="💬",
    layout="centered",
    initial_sidebar_state="collapsed",
)

# Streamlit CSS configuration
with open("styles/styles.css") as css:
    st.markdown(f"<style>{css.read()}</style>", unsafe_allow_html=True)


# Get runnable and memory
def initialize_runnable_and_memory():
    try:
        return get_runnable(model="gpt-4o", temperature=0)
    except Exception:
        st.warning(ERROR_MESSAGE, icon="🙁")
        st.stop()


# Get the ThreadPoolExecutor
if "executor" not in st.session_state:
    st.session_state.executor = ThreadPoolExecutor(max_workers=4)

executor = st.session_state.executor

# Submit initialization task if not already done
if "initialization_future" not in st.session_state:
    st.session_state["initialization_future"] = executor.submit(
        initialize_runnable_and_memory
    )

# Check if initialization is complete
future = st.session_state["initialization_future"]
if future.done() and "runnable" not in st.session_state:
    st.session_state["runnable"], st.session_state["memory"] = future.result()
    st.session_state["memory"].clear()

# Other session state variables
if "messages" not in st.session_state:
    st.session_state["messages"] = []

if "selected_location" not in st.session_state:
    st.session_state["selected_location"] = None

if "disable_chat_input" not in st.session_state:
    st.session_state["disable_chat_input"] = True


# Welcome message and Selectbox for location preferences
def welcome_message():
    st.markdown(
        "Hello there! 👋 Need help finding the right service or practitioner? Let our AI assistant give you a hand.\n\n"
        "To get started, please select your preferred location and share details about your symptoms or needs. "
    )


def on_change_location():
    st.session_state["disable_chat_input"] = (
        False if st.session_state["selected_location"] else True
    )


with st.container():
    welcome_message()
    location = st.radio(
        "**Our Locations**:",
        (
            "Cordova Bay - Victoria",
            "James Bay - Victoria",
            "Commercial Drive - Vancouver",
        ),
        index=None,
        label_visibility="visible",
        key="selected_location",
        on_change=on_change_location,
    )
    st.markdown("<br>", unsafe_allow_html=True)

# Get user input only if a location is selected
user_input = st.chat_input(
    "Ask ELLA...", disabled=st.session_state["disable_chat_input"]
)

if user_input and user_input.strip():
    st.session_state["messages"].append(ChatMessage(role="user", content=user_input))
    prompt = f"{user_input}\nLocation preference: {st.session_state.selected_location}."

else:
    prompt = None

# Render chat messages
user_avatar = "images/user.png"
ai_avatar = "images/tall-tree-logo.png"
for msg in st.session_state["messages"]:
    avatar = user_avatar if msg.role == "user" else ai_avatar
    with st.chat_message(msg.role, avatar=avatar):
        st.markdown(msg.content)

# Chat interface (we have to wait for the runnable initialization to complete)
if "runnable" in st.session_state and prompt:
    # Render the assistant's response
    with st.chat_message("assistant", avatar=ai_avatar):
        message_placeholder = st.empty()
        try:
            response = ""
            with st.spinner(" "):
                for chunk in st.session_state["runnable"].stream({"message": prompt}):
                    response += chunk
                    message_placeholder.markdown(response + "|")

            message_placeholder.markdown(response)
        except openai.BadRequestError:
            st.warning(ERROR_MESSAGE, icon="🙁")
            st.stop()
        except Exception:
            st.warning(ERROR_MESSAGE, icon="🙁")
            st.stop()

        # Add response to the message history
        st.session_state["messages"].append(
            ChatMessage(role="assistant", content=response)
        )

        # Add messages to memory
        st.session_state["memory"].chat_memory.add_user_message(
            HumanMessage(content=prompt)
        )
        st.session_state["memory"].chat_memory.add_ai_message(
            AIMessage(content=response)
        )
if st.session_state.executor:
    st.session_state.executor.shutdown(wait=False)