app.py

import streamlit as st
import pandas as pd
import matplotlib.pyplot as plt
from datetime import date, datetime
import numpy as np
import os
import json

# Local storage file for user credentials
CREDENTIALS_FILE = "user_credentials.json"

# Initialize credentials file if it doesn't exist
def initialize_credentials_file():
    if not os.path.exists(CREDENTIALS_FILE):
        with open(CREDENTIALS_FILE, "w") as f:
            json.dump({}, f)

# Save user credentials
def save_user_credentials(username, password):
    with open(CREDENTIALS_FILE, "r") as f:
        credentials = json.load(f)
    credentials[username] = password
    with open(CREDENTIALS_FILE, "w") as f:
        json.dump(credentials, f)

# Validate user credentials
def validate_credentials(username, password):
    with open(CREDENTIALS_FILE, "r") as f:
        credentials = json.load(f)
    return credentials.get(username) == password

# Check if username exists
def username_exists(username):
    with open(CREDENTIALS_FILE, "r") as f:
        credentials = json.load(f)
    return username in credentials

# Initialize credentials file
initialize_credentials_file()

# Session state for user management
if "is_authenticated" not in st.session_state:
    st.session_state["is_authenticated"] = False
if "current_user" not in st.session_state:
    st.session_state["current_user"] = None

# Initialize session state
if "income_data" not in st.session_state:
    st.session_state["income_data"] = pd.DataFrame(columns=["Date", "Category", "Amount"])

if "expense_data" not in st.session_state:
    st.session_state["expense_data"] = pd.DataFrame(columns=["Date", "Category", "Amount"])

if "custom_income_sources" not in st.session_state:
    st.session_state["custom_income_sources"] = []

if "custom_expense_categories" not in st.session_state:
    st.session_state["custom_expense_categories"] = []

if "saving_goals" not in st.session_state:
    st.session_state["saving_goals"] = pd.DataFrame(columns=["Goal", "Target Amount", "Current Savings", "Deadline", "Allocated Savings"])

# Helper functions
def format_date(date_obj):
    return date_obj.strftime("%d-%m-%y")

def update_transaction_log():
    st.session_state["transaction_log"] = pd.concat([ 
        st.session_state["income_data"].assign(Type="Income"),
        st.session_state["expense_data"].assign(Type="Expense")
        #st.session_state["saving_transaction_log"].assign(Type="Saving")
    ]).reset_index(drop=True)
    st.session_state["transaction_log"].index += 1

if "transaction_log" not in st.session_state:
    update_transaction_log()

# Login and Sign-Up Pages
def login_page():
    st.title("Login")
    username = st.text_input("Username")
    password = st.text_input("Password", type="password")
    if st.button("Login"):
        if validate_credentials(username, password):
            st.session_state["is_authenticated"] = True
            st.session_state["current_user"] = username
            st.success("Login successful!")
            st.rerun()
        else:
            st.error("Invalid username or password")

def signup_page():
    st.title("Sign Up")
    username = st.text_input("Choose a Username")
    password = st.text_input("Choose a Password", type="password")
    if st.button("Sign Up"):
        if username_exists(username):
            st.error("Username already exists. Please choose a different username.")
        else:
            save_user_credentials(username, password)
            st.success("Sign up successful! You can now log in.")

# Main app after login
def main_app():
    # Sidebar for navigation
    st.sidebar.title("Navigation")
    tabs = st.sidebar.radio("", ["Home", "Record Income", "Record Expense", "Transaction Log", "Savings", "Budget Recommendations", "Logout"])

    # Home Tab
    if tabs == "Home":
        # Total income, expense, and net savings
        total_income = st.session_state['income_data']['Amount'].sum()
        total_expense = st.session_state['expense_data']['Amount'].sum()
        allocated_savings = st.session_state["saving_goals"]["Allocated Savings"].sum()
        net_savings = total_income - total_expense - allocated_savings
        
        # Cash in hand (remaining income after subtracting expenses and allocated savings)
        cash_in_hand = total_income - total_expense - allocated_savings
    
        # Show metrics
        col1, col2, col3 = st.columns(3)
        col1.metric("Total Income", f"{total_income:,}")
        col2.metric("Total Expense", f"{total_expense:,}")
        col3.metric("Net Savings", f"{net_savings:,}")
        
        # Display Cash in Hand (remaining after expenses and savings)
        col4, col5 = st.columns(2)
        col4.metric("Cash in Hand", f"{cash_in_hand:,}")
    
        # Find the nearest goal
        if not st.session_state["saving_goals"].empty:
            closest_goal = st.session_state["saving_goals"].iloc[0]  # Default to first goal
            closest_goal_amount = closest_goal["Target Amount"] - closest_goal["Current Savings"]
            closest_goal_name = closest_goal["Goal"]
            closest_goal_deadline = closest_goal["Deadline"]
            
            # Loop through goals and find the closest one based on the deadline
            for _, goal in st.session_state["saving_goals"].iterrows():
                remaining_amount = goal["Target Amount"] - goal["Current Savings"]
                if goal["Deadline"] < closest_goal_deadline and remaining_amount > 0:
                    closest_goal = goal
                    closest_goal_name = goal["Goal"]
                    closest_goal_deadline = goal["Deadline"]
                    closest_goal_amount = remaining_amount
    
            # Display label for the nearest goal
            st.write(f"Amount needed to reach goal '{closest_goal_name}': {closest_goal_amount:,} (Deadline: {closest_goal_deadline})")

        if total_income > 0 and total_expense > 0:
            # Pie chart for income breakdown
            labels = ['Expense', 'Savings', 'Unallocated Income']
            sizes = [total_expense, allocated_savings, cash_in_hand]
            sizes = [0 if np.isnan(value) else value for value in sizes]
            colors = ['#ff9999','#66b3ff','#99ff99']
            
            fig, ax = plt.subplots()
            ax.pie(sizes, labels=labels, autopct='%1.1f%%', startangle=90, colors=colors)
            ax.axis('equal')  # Equal aspect ratio ensures that pie chart is drawn as a circle.
            st.pyplot(fig)
    
        # Progress bar for each goal
        for idx, goal in st.session_state["saving_goals"].iterrows():
            goal_name = goal["Goal"]
            target_amount = goal["Target Amount"]
            current_savings = goal["Current Savings"]
            
            progress = current_savings / target_amount * 100  # Progress as percentage
            
            st.subheader(f"Progress for Goal: {goal_name}")
            st.progress(progress)
            st.write(f"Target Amount: {target_amount}, Current Savings: {current_savings}")

    # Record Income Tab
    elif tabs == "Record Income":
        st.header("Record Income")
        with st.form("income_form"):
            income_date = st.date_input("Date", value=date.today())
            income_source = st.selectbox("Source", ["Salary", "Freelance", "Investments"] + st.session_state["custom_income_sources"])
            income_amount = st.number_input("Amount", min_value=0, step=1)
            submit_income = st.form_submit_button("Add Income")

        if submit_income:
            new_entry = {"Date": income_date, "Category": "Income from "+income_source, "Amount": income_amount}
            st.session_state["income_data"] = pd.concat(
                [st.session_state["income_data"], pd.DataFrame([new_entry])], ignore_index=True
            )
            update_transaction_log()
            st.success("Income added successfully!")

        if not st.session_state["income_data"].empty:
            fig, ax = plt.subplots()
            st.session_state['income_data']['Date'] = pd.to_datetime(st.session_state['income_data']['Date'])
            sorted_data = st.session_state["income_data"].sort_values("Date")
            ax.bar(sorted_data["Date"], sorted_data["Amount"], label='Income', width=0.4)
            ax.plot(sorted_data["Date"], sorted_data["Amount"].cumsum(), label='Cumulative Income', marker='o', color='green')
            ax.set_title("Income Over Time")
            ax.set_xlabel("Date")
            ax.set_ylabel("Amount")
            plt.xticks(rotation=45)
            ax.legend()
            st.pyplot(fig)

    # Record Expense Tab
    elif tabs == "Record Expense":
        st.header("Record Expense")
        with st.form("expense_form"):
            expense_date = st.date_input("Date", value=date.today())
            expense_category = st.selectbox("Category", ["Food", "Travel", "Utilities"] + st.session_state["custom_expense_categories"])
            expense_amount = st.number_input("Amount", min_value=0, step=1)
            submit_expense = st.form_submit_button("Add Expense")

        if submit_expense:
            new_entry = {"Date": expense_date, "Category": "Expense for " + expense_category, "Amount": expense_amount}
            st.session_state["expense_data"] = pd.concat(
                [st.session_state["expense_data"], pd.DataFrame([new_entry])], ignore_index=True
            )
            update_transaction_log()
            st.success("Expense added successfully!")

        if not st.session_state["expense_data"].empty:
            fig, ax = plt.subplots()
            st.session_state['expense_data']['Date'] = pd.to_datetime(st.session_state['expense_data']['Date'])
            sorted_data = st.session_state["expense_data"].sort_values("Date")
            ax.bar(sorted_data["Date"], sorted_data["Amount"], label='Expense', width=0.4)
            ax.plot(sorted_data["Date"], sorted_data["Amount"].cumsum(), label='Cumulative Expense', marker='o', color='red')
            ax.set_title("Expenses Over Time")
            ax.set_xlabel("Date")
            ax.set_ylabel("Amount")
            plt.xticks(rotation=45)
            ax.legend()
            st.pyplot(fig)

    # Transaction Log Tab
    elif tabs == "Transaction Log":
        st.header("Transaction Log")
        
        # Check if income, expense, or saving transactions exist
        if "income_data" in st.session_state and "expense_data" in st.session_state:
            
            # Concatenate income, expense, and saving transactions
            transaction_log = pd.concat([
                st.session_state["income_data"].assign(Type="Income"),
                st.session_state["expense_data"].assign(Type="Expense")
            ]).sort_values(by="Date")

            if "saving_transaction_log" in st.session_state:
                transaction_log = pd.concat([
                    st.session_state["income_data"].assign(Type="Income"),
                    st.session_state["expense_data"].assign(Type="Expense"),
                    st.session_state["saving_transaction_log"].assign(Type="Saving")  # Add saving transactions
                ]).sort_values(by="Date")
                
            # Ensure 'Date' column is of type datetime64
            transaction_log["Date"] = pd.to_datetime(transaction_log["Date"])
            
            # Display the combined transaction log
            st.dataframe(transaction_log)
        else:
            st.warning("No transactions recorded yet.")


    # Set Saving Goals Tab
    elif tabs == "Savings":
        st.header("Savings Goals")
        
        # Fetch net savings from Home tab
        total_income = st.session_state['income_data']['Amount'].sum()
        total_expense = st.session_state['expense_data']['Amount'].sum()
        net_savings = 0
        max_savings = total_income - total_expense - net_savings
        
        # Initialize session state for buttons if not already done
        if "show_set_goal_form" not in st.session_state:
            st.session_state["show_set_goal_form"] = False
        if "show_allocate_savings_form" not in st.session_state:
            st.session_state["show_allocate_savings_form"] = False
        
        # Buttons to toggle between setting goal and allocating savings
        set_goal_button = st.button("Set Saving Goal")
        allocate_savings_button = st.button("Allocate Saving to Goal")
        
        # Toggle the display state for each form
        if set_goal_button:
            st.session_state["show_set_goal_form"] = True
            st.session_state["show_allocate_savings_form"] = False  # Hide other form
        if allocate_savings_button:
            st.session_state["show_allocate_savings_form"] = True
            st.session_state["show_set_goal_form"] = False  # Hide other form
        
        # Set Saving Goal Form
        if st.session_state["show_set_goal_form"]:
            st.subheader("Set Saving Goal")
            goal_name = st.text_input("Goal Name")
            target_amount = st.number_input("Target Amount", min_value=0, step=100)
            goal_deadline = st.date_input("Deadline", value=date.today())
            
            # Button to create a new goal
            if st.button("Create Goal"):
                if goal_name and target_amount > 0:
                    new_goal = {"Goal": goal_name, 
                                "Target Amount": target_amount, 
                                "Current Savings": net_savings, 
                                "Deadline": goal_deadline, 
                                "Allocated Savings": 0}
                    st.session_state["saving_goals"] = pd.concat(
                        [st.session_state["saving_goals"], pd.DataFrame([new_goal])], ignore_index=True
                    )
                    st.success("Goal set successfully!")
                else:
                    st.error("Please provide valid goal name and target amount.")
        
        # Allocate Savings Form
        if st.session_state["show_allocate_savings_form"]:
            st.subheader("Allocate Savings to Goals")
            if not st.session_state["saving_goals"].empty:
                # Add a dropdown to select a goal
                goal_name_selected = st.selectbox("Select Saving Goal", st.session_state["saving_goals"]["Goal"].values)
                
                if goal_name_selected:
                    # Fetch the selected goal details
                    selected_goal = st.session_state["saving_goals"][st.session_state["saving_goals"]["Goal"] == goal_name_selected].iloc[0]
                    
                    # Show the current progress and target amount of the selected goal
                    st.write(f"**{goal_name_selected}**")
                    st.write(f"Target Amount: {selected_goal['Target Amount']}, Current Savings: {selected_goal['Current Savings']}, Deadline: {selected_goal['Deadline']}")
            
                    # Input field to allocate savings
                    allocated_savings = st.number_input(f"Enter Amount to Allocate for {goal_name_selected}", 
                                                       min_value=0, max_value=max_savings, step=100, key=f"allocate_{goal_name_selected}")
            
                    # Button to save the allocation for a goal
                    save_allocation_button = st.button(f"Save Allocation for {goal_name_selected}")
                    
                    if save_allocation_button and allocated_savings > 0:
                        # Find the index of the selected goal and update the savings
                        idx = st.session_state["saving_goals"][st.session_state["saving_goals"]["Goal"] == goal_name_selected].index[0]
                    
                        # Update the saving goal
                        st.session_state["saving_goals"].at[idx, "Allocated Savings"] += allocated_savings
                        max_savings -= allocated_savings  # Adjust max savings
                        st.session_state["saving_goals"].at[idx, "Current Savings"] += allocated_savings  # Update current savings
                        
                        # Ensure the transaction log exists in session_state
                        if "saving_transaction_log" not in st.session_state:
                            st.session_state["saving_transaction_log"] = pd.DataFrame(columns=["Date", "Amount", "Category"])
                    
                        # Append the transaction entry for the saving allocation
                        transaction_entry = {
                            "Date": pd.to_datetime("today"),  # Ensuring Date is a datetime object
                            "Amount": allocated_savings,
                            "Category": "Savings for " + goal_name_selected
                        }
                        
                        # Append the new transaction entry to the transaction log
                        st.session_state["saving_transaction_log"] = st.session_state["saving_transaction_log"].append(transaction_entry, ignore_index=True)
                        
                        # Success message
                        st.success(f"Allocated {allocated_savings} to goal '{goal_name_selected}'")
                        
                    elif save_allocation_button:
                        st.error("Please allocate a valid amount greater than 0.")






        else:
            st.write("No saving goals set yet.")

        
        # Display current goals and their progress
        if not st.session_state["saving_goals"].empty:
            st.subheader("Current Goals and Allocated Savings")
            for idx, goal in st.session_state["saving_goals"].iterrows():
                progress = (goal["Current Savings"] / goal["Target Amount"]) if goal["Target Amount"] > 0 else 0
                st.write(f"**{goal['Goal']}**")
                st.write(f"Target Amount: {goal['Target Amount']}, Current Savings: {goal['Current Savings']}, Deadline: {goal['Deadline']}")
                st.progress(progress)  # progress as a fraction (0.0 to 1.0)
                st.write(f"Progress: {progress * 100:.2f}%")  # Display as a percentage
    
            # Option to delete a goal
            delete_goal_idx = st.selectbox("Select Goal to Delete", options=[""] + list(st.session_state["saving_goals"]["Goal"]))
            if delete_goal_idx:
                st.session_state["saving_goals"] = st.session_state["saving_goals"][st.session_state["saving_goals"]["Goal"] != delete_goal_idx]
                st.success(f"Goal '{delete_goal_idx}' deleted successfully.")
        else:
            st.write("No savings goals set yet.")


    # Budget Recommendations Tab
    elif tabs == "Budget Recommendations":
        st.header("Budget Recommendations")
        if st.session_state["income_data"].empty or st.session_state["expense_data"].empty:
            st.warning("Please record your income and expenses before getting budget recommendations.")
        else:
            total_income = st.session_state["income_data"]["Amount"].sum()
            total_expense = st.session_state["expense_data"]["Amount"].sum()

            # Display budget allocation advice
            budget_allocation = {
                "Housing": total_income * 0.30,
                "Transportation": total_income * 0.15,
                "Food": total_income * 0.10,
                "Savings": total_income * 0.20,
                "Entertainment": total_income * 0.05,
                "Health": total_income * 0.10,
                "Miscellaneous": total_income * 0.10
            }
            st.write("Budget Recommendations based on your income:")
            for category, amount in budget_allocation.items():
                st.write(f"{category}: {amount:,.2f}")

    # Logout Tab
    elif tabs == "Logout":
        st.session_state["is_authenticated"] = False
        st.session_state["current_user"] = None
        st.success("Logged out successfully!")
        st.rerun()

# Streamlit App Logic
if not st.session_state["is_authenticated"]:
    page = st.selectbox("Choose a page", ["Login", "Sign Up"])
    if page == "Login":
        login_page()
    elif page == "Sign Up":
        signup_page()
else:
    main_app()