Python Expense Tracker Project

"""A small command-line expense tracker that saves entries in expenses.json."""

import json
from datetime import date
from decimal import Decimal, InvalidOperation
from pathlib import Path

DATA_FILE = Path("expenses.json")


def load_expenses():
    """Return saved expenses, or an empty list when no data exists yet."""
    if not DATA_FILE.exists():
        return []
    try:
        return json.loads(DATA_FILE.read_text(encoding="utf-8"))
    except json.JSONDecodeError:
        print("The saved file could not be read. Starting with an empty list.")
        return []


def save_expenses(expenses):
    DATA_FILE.write_text(json.dumps(expenses, indent=2), encoding="utf-8")


def read_amount():
    while True:
        try:
            amount = Decimal(input("Amount: Rs. ").strip())
            if amount <= 0:
                raise ValueError
            return amount.quantize(Decimal("0.01"))
        except (InvalidOperation, ValueError):
            print("Enter a positive amount, for example 125.50.")


def add_expense(expenses):
    category = input("Category (for example Food or Travel): ").strip() or "Other"
    note = input("Short note: ").strip() or "No note"
    amount = read_amount()
    expenses.append(
        {"date": str(date.today()), "category": category, "note": note, "amount": str(amount)}
    )
    save_expenses(expenses)
    print("Expense saved.\n")


def show_expenses(expenses):
    if not expenses:
        print("No expenses have been saved yet.\n")
        return

    total = Decimal("0")
    print("\nDate        Category       Amount     Note")
    print("-" * 54)
    for item in expenses:
        amount = Decimal(item["amount"])
        total += amount
        print(f"{item['date']:<11} {item['category'][:13]:<14} Rs. {amount:>8.2f}  {item['note']}")
    print("-" * 54)
    print(f"Total spent: Rs. {total:.2f}\n")


def main():
    expenses = load_expenses()
    print("Simple Expense Tracker")
    while True:
        print("1. Add expense  2. View expenses  3. Quit")
        choice = input("Choose an option: ").strip()
        if choice == "1":
            add_expense(expenses)
        elif choice == "2":
            show_expenses(expenses)
        elif choice in {"3", "q", "quit", "exit"}:
            print("Your expense data is saved in expenses.json.")
            break
        else:
            print("Choose 1, 2, or 3.\n")


if __name__ == "__main__":
    main()