app.py

import os
from langchain_core.prompts import ChatPromptTemplate
from langchain_google_genai import ChatGoogleGenerativeAI
from langchain_core.prompts import MessagesPlaceholder
from langchain.memory import ConversationBufferWindowMemory
from operator import itemgetter
from langchain_core.runnables import RunnableLambda,RunnablePassthrough
import streamlit as st

genai_key = os.getenv("gen_key")

model = ChatGoogleGenerativeAI(temperature=0,model='gemini-1.5-pro',max_output_tokens=150,convert_system_message_to_human=True,google_api_key=genai_key)

prompt=ChatPromptTemplate.from_messages([
     ("system","you are a good assistant"),
     MessagesPlaceholder(variable_name="history"),
     ("human","{input}")])


memory=ConversationBufferWindowMemory(k=3,return_messages=True)

chain=(RunnablePassthrough.assign(history=RunnableLambda(memory.load_memory_variables)|
       itemgetter("history"))|prompt|model)

# Streamlit interface
st.title("chat bot")
st.write("Enter your input text:")


def end_conv():
        st.write("Conversation ended.")
        st.session_state.conversation_history = []

    # Initialize session state for conversation history if not already done
if 'conversation_history' not in st.session_state:
    st.session_state.conversation_history = []

    # User input
user_input = st.text_area("Input Text")

    # Generate and display the response
if st.button("Generate Response"):
        # Load current conversation history
    history = memory.load_memory_variables({})['history']

        # Invoke the chain to get the response
    res = chain.invoke({"input": user_input})
    response_content = res.content
    st.write("Generated Response:")
    st.write(response_content)

        # Save the context in memory and session state
    memory.save_context({"input": user_input}, {"output": response_content})
    st.session_state.conversation_history.extend([{"role": "human", "content": user_input}, {"role": "assistant", "content": response_content}])

        # Display the updated conversation history
        #st.write("Conversation History:")
        #for msg in st.session_state.conversation_history:
         #   st.write(f"{msg['role']}: {msg['content']}")

    # End conversation button
    if st.button("End Conversation"):
        end_conv()