#!/usr/bin/env python3

from datetime import datetime, timedelta

def calculate_reach_date(current_hours, max_hours, hours_added_bi_weekly):
    """
    Calculates the estimated date when the maximum Paid Time Off (PTO) hours will be reached.

    Parameters:
    - current_hours (float): The current total of PTO hours accumulated by the user.
    - max_hours (float): The maximum PTO hours that can be accumulated.
    - hours_added_bi_weekly (float): The number of PTO hours added every two weeks.

    Returns:
    - datetime.date: The estimated date when the maximum PTO balance is reached.
    """
    # Calculate the additional hours needed to reach the maximum
    hours_needed = max_hours - current_hours

    # Determine the number of bi-weekly periods needed to accumulate the necessary hours
    bi_weekly_periods_needed = hours_needed / hours_added_bi_weekly

    # Convert the period into days
    days_needed = bi_weekly_periods_needed * 14  # Two weeks per bi-weekly period

    # Calculate the future date when the maximum will be reached
    reach_date = datetime.now() + timedelta(days=days_needed)
    return reach_date

# Constants for the program
MAX_HOURS = 240  # The maximum PTO balance allowed
# The standard rate of PTO accrual every two weeks
HOURS_ADDED_BI_WEEKLY = 6.15384615
# An alternative accrual rate for different scenarios (commented out by default)
# HOURS_ADDED_BI_WEEKLY = 7.69230769
LAST_KNOWN_PTO_BALANCE = 220.08  # An example of a last known PTO balance

# Introduction and instructions for the user
print("PTO Balance Calculator")
print("----------------------")
print("Determine when you will reach your maximum PTO balance based on your current accrual.")

# Display the last known PTO balance to assist with user input
print(f"\nLast known PTO balance: {LAST_KNOWN_PTO_BALANCE}\n")

# Handling user input
try:
    # Prompting the user to enter their current PTO balance
    current_hours_input = input("Enter your current PTO hours: ")
    current_hours = float(current_hours_input.strip())  # Convert input to a floating-point number
    
    # Calculation based on user input
    reach_date = calculate_reach_date(current_hours, MAX_HOURS, HOURS_ADDED_BI_WEEKLY)

    # Displaying the calculation results
    print("\nCalculation Results")
    print("-------------------")
    print(f"Today's Date: {datetime.now().strftime('%A, %B %d, %Y')}")
    print(f"Maximum PTO balance of {MAX_HOURS} hours will be reached on: {reach_date.strftime('%A, %B %d, %Y')}.")
except ValueError:
    # Error handling for non-numeric inputs
    print("Error: Please enter a valid number for your current PTO hours.")