app.py

import os
import streamlit as st
import chatbot as demo_chat
from transformers import AutoModelForCausalLM, AutoTokenizer

st.title("Hi, I am Chatbot Philio :mermaid:")
st.write("I am your hotel booking assistant for today.")

tokenizer, model = demo_chat.load_model()

scrollable_div_style = """
<style>
.scrollable-div {
    height: 200px;  /* Adjust the height as needed */
    overflow-y: auto;  /* Enable vertical scrolling */
    padding: 5px;
    border: 1px solid #ccc;  /* Optional: adds a border around the div */
    border-radius: 5px;  /* Optional: rounds the corners of the border */
}
</style>
"""

def render_chat_history(chat_history):
    #renders chat history
    for message in chat_history:
        if(message["role"]!= "system"):
            with st.chat_message(message["role"]):
                st.markdown(message["content"])

def generate_response(chat_history):
    tokenized_chat = tokenizer.apply_chat_template(chat_history, tokenize=True, add_generation_prompt=True, return_tensors="pt")
    outputs = model.generate(tokenized_chat, do_sample =True, max_new_tokens=50, temperature = 0.3, top_p = 0.85)
    answer = tokenizer.decode(outputs[0][tokenized_chat.shape[1]:],skip_special_tokens=True)
    final_answer = answer.split("<")[0]
    return final_answer

#Application 
#Langchain memory in session cache 
if 'memory' not in st.session_state:
    st.session_state.memory = demo_chat.demo_miny_memory(model)

system_content = "You are a friendly chatbot who always helps the user book a hotel room based on his/her needs.Based on the current social norms you wait for the user's response to your proposals."
#Check if chat history exists in this session
if 'chat_history' not in st.session_state:
    st.session_state.chat_history = [
        {
            "role": "system",
            "content": system_content,
        },
        {"role": "assistant", "content": "Hello, how can I help you today?"},
    ] #Initialize chat history
    
if 'model' not in st.session_state:
    st.session_state.model = model
    
st.markdown('<div class="scrollable-div">', unsafe_allow_html=True) #add css style to container
render_chat_history(st.session_state.chat_history)

#Input field for chat interface
if input_text := st.chat_input(placeholder="Here you can chat with our hotel booking model."):
    
    with st.chat_message("user"):
        st.markdown(input_text)
    st.session_state.chat_history.append({"role" : "user", "content" : input_text}) #append message to chat history

    with st.spinner("Generating response..."):
        first_answer = generate_response(st.session_state.chat_history)
        
        with st.chat_message("assistant"):
            st.markdown(first_answer)
        st.session_state.chat_history.append({"role": "assistant", "content": first_answer})    
st.markdown('</div>', unsafe_allow_html=True)