app.py

import streamlit as st
import pandas as pd
from langchain.agents.agent_types import AgentType
from langchain_experimental.agents.agent_toolkits import create_pandas_dataframe_agent
from langchain_community.llms import Ollama

# Streamlit UI
st.title("Excel ChatBot (Free - Local Model)")
st.subheader("Stack: LangChain Agent, Streamlit, Ollama (Mistral)")

uploaded_file = st.file_uploader("Upload CSV or Excel", type=['csv','xlsx'])

# Load dataframe
if uploaded_file is None:
    df = pd.read_csv("titanic.csv")
    st.write("Using default Titanic dataset.")
else:
    if uploaded_file.name.endswith(".csv"):
        df = pd.read_csv(uploaded_file)
    elif uploaded_file.name.endswith(".xlsx"):
        df = pd.read_excel(uploaded_file)

st.dataframe(df, height=300)

# Load local LLM using Ollama (make sure `ollama run mistral` is running)
llm = Ollama(model="mistral")

# Create LangChain agent
agent = create_pandas_dataframe_agent(
    llm,
    df,
    verbose=True,
    agent_type=AgentType.OPENAI_FUNCTIONS  # Still works, just the name
)

# Chat input
if question := st.chat_input("Ask a question about the data"):
    response = agent.invoke(question)
    st.chat_message("user").markdown(question)
    st.chat_message("assistant").markdown(response["output"])