Code Editor for app.py

import streamlit as st
import pandas as pd
import plotly.express as px

# Initialize session state for authentication
if 'authenticated' not in st.session_state:
    st.session_state.authenticated = False

if 'messages' not in st.session_state:
    st.session_state.messages = []

# Load sample data
@st.cache_data
def load_sample_data():
    # Using a sample dataset about car sales
    data = {
        'manufacturer': ['Toyota', 'Honda', 'Ford', 'BMW', 'Mercedes'],
        'sales': [150000, 130000, 120000, 80000, 90000],
        'satisfaction': [4.5, 4.3, 4.1, 4.7, 4.6]
    }
    return pd.DataFrame(data)

def login():
    # Hardcoded credentials for demo (in real app, use secure authentication)
    valid_username = "demo"
    valid_password = "password123"
    
    with st.sidebar:
        st.title("Login")
        username = st.text_input("Username")
        password = st.text_input("Password", type="password")
        
        if st.button("Login"):
            if username == valid_username and password == valid_password:
                st.session_state.authenticated = True
                st.success("Logged in successfully!")
                st.rerun()
            else:
                st.error("Invalid credentials")

def main():
    # Sidebar
    with st.sidebar:
        st.title("Navigation")
        st.write(f"Welcome, User!")
        if st.button("Logout"):
            st.session_state.authenticated = False
            st.rerun()

    # Main content
    st.title("Data Analytics Dashboard")
    
    # Load data
    df = load_sample_data()
    
    # Create tabs
    tab1, tab2 = st.tabs(["Data Visualization", "Chat Interface"])
    
    with tab1:
        st.header("Sales Analysis")
        
        # Create bar chart using plotly
        fig = px.bar(
            df,
            x='manufacturer',
            y='sales',
            title='Sales by Manufacturer',
            labels={'manufacturer': 'Manufacturer', 'sales': 'Sales'},
            color='satisfaction'
        )
        st.plotly_chart(fig)
        
        # Show raw data
        st.subheader("Raw Data")
        st.dataframe(df)
    
    with tab2:
        st.header("Chat with Data Assistant")
        
        # Display chat messages from history
        for message in st.session_state.messages:
            with st.chat_message(message["role"]):
                st.markdown(message["content"])
        
        # Chat input
        if prompt := st.chat_input("Ask about the data..."):
            # Add user message to chat history
            st.session_state.messages.append({"role": "user", "content": prompt})
            
            # Display user message
            with st.chat_message("user"):
                st.markdown(prompt)
            
            # Generate and display assistant response
            response = f"I can help you analyze the data. For example, I can tell you that Toyota has the highest sales with {df['sales'].max():,} units."
            
            with st.chat_message("assistant"):
                st.markdown(response)
            
            # Add assistant response to chat history
            st.session_state.messages.append({"role": "assistant", "content": response})

# Main app logic
if not st.session_state.authenticated:
    login()
else:
    main()