import tkinter as tk

def validate_numeric_input(P):
    """Validate that input is a positive number or empty."""
    if P == "":
        return True  # Allow empty input
    try:
        value = float(P)
        return value >= 0
    except ValueError:
        return False

def format_currency(value):
    """Format a number as currency with two decimal places."""
    return f"${value:,.2f}"

def calculate_dividend_income(amount, quantity, frequency, days):
    """Calculate total dividend income over the given period."""
    # Map frequency to number of payments per year
    freq_map = {"Monthly": 12, "Quarterly": 4, "Annually": 1}
    payments_per_year = freq_map.get(frequency, 0)
    if payments_per_year == 0:
        return 0  # Invalid frequency
    # Calculate the number of payments within the given days
    payments = (days / 365) * payments_per_year
    return amount * quantity * payments