app.py

# import os 
# import streamlit as st
# from langchain.chains import ConversationChain
# from langchain_openai import ChatOpenAI
# from langchain.memory import ConversationBufferMemory

# os.environ["OPENAI_API_KEY"] = ""

# # Intialize the chatbot
# @st.cache_resource
# def init_chatbot():
#     memory = ConversationBufferMemory()
#     chatbot = ConversationChain(
#         llm =ChatOpenAI(model = "gpt-4o-mini"),
#         memory = memory,
#         verbose = False
#     )

#     return chatbot

# # Streamlit Application
# st.title("Langchain Chatbot")
# st.write("Hi, I'm a chatbot built with Langchain powered by GPT. How can I assist you today?")

# user_input = st.text_input("You:", placeholder = "Ask me anything....")

# if user_input:
#     with st.spinner("Thinking......"):
#         resp = chatbot.run(user_input)
#         st.write(f"Chatbot: {resp}")



import os
import streamlit as st
from langchain.chains import ConversationChain
from langchain_openai import ChatOpenAI
from langchain.memory import ConversationBufferMemory
from streamlit_extras.add_vertical_space import add_vertical_space
from streamlit_extras.chat_elements import message

# Set OpenAI API Key (Ensure you add it in Streamlit Secrets)
if "openai_api_key" in st.secrets:
    os.environ["OPENAI_API_KEY"] = st.secrets["openai_api_key"]
else:
    st.error("🔑 OpenAI API Key is missing! Please add it to Streamlit secrets.")
    st.stop()

# Initialize chatbot
def init_chatbot(model="gpt-4o-mini"):
    memory = ConversationBufferMemory()
    return ConversationChain(llm=ChatOpenAI(model=model), memory=memory, verbose=False)

if "chatbot" not in st.session_state:
    st.session_state.chatbot = init_chatbot()

# Custom Styling
st.markdown("""
    <style>
        body {
            background-color: #f5f5f5;
        }
        .chat-container {
            background-color: #ffffff;
            padding: 20px;
            border-radius: 10px;
            box-shadow: 0px 4px 6px rgba(0,0,0,0.1);
        }
    </style>
""", unsafe_allow_html=True)

# Sidebar - Settings
st.sidebar.title("⚙️ Settings")
model_choice = st.sidebar.radio("Select Model", ("gpt-4o-mini", "gpt-4", "gpt-3.5-turbo"))

# Update chatbot model if changed
if model_choice != st.session_state.chatbot.llm.model_name:
    st.session_state.chatbot = init_chatbot(model_choice)

# Title and Description
st.title("💬 LangChain AI Chatbot")
st.write("### Hi, I'm a chatbot built with LangChain powered by GPT. How can I assist you today?")

# Chat history
if "chat_history" not in st.session_state:
    st.session_state.chat_history = []

# User Input
user_input = st.text_input("You:", placeholder="Ask me anything...")

# Process input
if user_input:
    with st.spinner("Thinking..."):
        response = st.session_state.chatbot.run(user_input)
        if response:
            st.session_state.chat_history.append(("user", user_input))
            st.session_state.chat_history.append(("bot", response))

# Display chat history
st.write("### 🗨️ Conversation")
chat_container = st.container()

with chat_container:
    for role, text in st.session_state.chat_history:
        if role == "user":
            message(text, is_user=True, avatar_style="thumbs")
        else:
            message(text, is_user=False, avatar_style="bottts")

# Add some spacing
add_vertical_space(2)

# Collapsible Chat History
with st.expander("📜 Chat History"):
    for role, text in st.session_state.chat_history:
        st.write(f"**{role.capitalize()}**: {text}")

# Footer
st.markdown("---")
st.markdown("Developed with ❤️ using Streamlit & LangChain")