import streamlit as st
import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns

# Initialize an empty DataFrame to hold expenses data
columns = ['Date', 'Category', 'Description', 'Amount']
if 'expenses_df' not in st.session_state:
    st.session_state['expenses_df'] = pd.DataFrame(columns=columns)

# Initialize a list for storing messages between user and bot
if 'messages' not in st.session_state:
    st.session_state['messages'] = []

# Function to add an expense
def add_expense(date, category, description, amount):
    new_expense = pd.DataFrame([[date, category, description, amount]], columns=st.session_state['expenses_df'].columns)
    st.session_state['expenses_df'] = pd.concat([st.session_state['expenses_df'], new_expense], ignore_index=True)

# Function to generate response for the chatbot
def chatbot_response(user_input):
    # If the user wants to add an expense, we can extract the details from the input
    if "add" in user_input.lower() and "expense" in user_input.lower():
        # Ask the user for details about the expense
        st.session_state['messages'].append({"role": "assistant", "content": "Please enter the date of the expense."})
        return "Please enter the date of the expense."

    elif "view" in user_input.lower():
        st.session_state['messages'].append({"role": "assistant", "content": str(st.session_state['expenses_df'])})
        return "Here are all your expenses:\n" + str(st.session_state['expenses_df'])
    
    elif "summary" in user_input.lower():
        category_summary = st.session_state['expenses_df'].groupby('Category')['Amount'].sum().reset_index()
        st.session_state['messages'].append({"role": "assistant", "content": str(category_summary)})
        return "Here is the expense suimport streamlit as st
import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns

# Initialize an empty DataFrame to hold expenses data
columns = ['Date', 'Category', 'Description', 'Amount']
if 'expenses_df' not in st.session_state:
    st.session_state['expenses_df'] = pd.DataFrame(columns=columns)

# Initialize a list for storing messages between user and bot
if 'messages' not in st.session_state:
    st.session_state['messages'] = []

# Function to add an expense
def add_expense(date, category, description, amount):
    new_expense = pd.DataFrame([[date, category, description, amount]], columns=st.session_state['expenses_df'].columns)
    st.session_state['expenses_df'] = pd.concat([st.session_state['expenses_df'], new_expense], ignore_index=True)

# Function to generate response for the chatbot
def chatbot_response(user_input):
    # If the user wants to add an expense, we can extract the details from the input
    if "add" in user_input.lower() and "expense" in user_input.lower():
        # Ask the user for details about the expense
        st.session_state['messages'].append({"role": "assistant", "content": "Please enter the date of the expense."})
        return "Please enter the date of the expense."

    elif "view" in user_input.lower():
        st.session_state['messages'].append({"role": "assistant", "content": str(st.session_state['expenses_df'])})
        return "Here are all your expenses:\n" + str(st.session_state['expenses_df'])
    
    elif "summary" in user_input.lower():
        category_summary = st.session_state['expenses_df'].groupby('Category')['Amount'].sum().reset_index()
        st.session_state['messages'].append({"role": "assistant", "content": str(category_summary)})
        return "Here is the expense summary by category:\n" + str(category_summary)

    elif "visualize" in user_input.lower():
        fig, ax = plt.subplots(figsize=(10, 6))
        sns.barplot(x='Category', y='Amount', data=st.session_state['expenses_df'], ax=ax)
        ax.set_title('Total Expenses by Category')
        ax.set_xlabel('Category')
        ax.set_ylabel('Amount Spent ($)')
        ax.set_xticklabels(ax.get_xticklabels(), rotation=45)
        st.pyplot(fig)
        return "Here is the bar chart showing total expenses by category."
    
    else:
        return "I'm sorry, I didn't understand that. You can add expenses, view expenses, or ask for a summary."

# Streamlit UI
st.title("Daily Expense Tracker - Chatbot")

# Display messages (chat history)
for message in st.session_state['messages']:
    if message["role"] == "assistant":
        st.chat_message("assistant").markdown(message["content"])
    else:
        st.chat_message("user").markdown(message["content"])

# User input for chatbot
user_input = st.text_input("You:", key="user_input")

if user_input:
    st.session_state['messages'].append({"role": "user", "content": user_input})

    # Get response from chatbot
    response = chatbot_response(user_input)

    st.session_state['messages'].append({"role": "assistant", "content": response})

# Expense Addition Flow
# Ensure there is at least one message and check for the assistant's message asking for date input
if st.session_state['messages'] and "Please enter the date of the expense." in st.session_state['messages'][-1].get("content", ""):
    date = st.date_input("Enter Expense Date")
    category = st.selectbox("Category", ['Food', 'Transport', 'Entertainment', 'Other'])
    description = st.text_input("Description")
    amount = st.number_input("Amount", min_value=0.0, format="%.2f")

    if st.button("Submit Expense"):
        add_expense(date, category, description, amount)
        st.session_state['messages'].append({"role": "assistant", "content": f"Expense added: {description} - ${amount:.2f}"})
        st.success(f"Added expense: {description} - ${amount:.2f}")