"""
The Luhn Algorithm is widely used for error-checking in various applications, such as verifying credit card numbers.

By building this project, you'll gain experience working with numerical computations and string manipulation.

"""

# TODO: To make it much more better and succint


def verify_card_number(card_number):
    sum_of_odd_digits = 0
    card_number_reversed = card_number[::-1]
    odd_digits = card_number_reversed[::2]

    for digit in odd_digits:
        sum_of_odd_digits += int(digit)

    sum_of_even_digits = 0
    even_digits = card_number_reversed[1::2]
    for digit in even_digits:
        number = int(digit) * 2
        if number >= 10:
            number = (number // 10) + (number % 10)
        sum_of_even_digits += number
    total = sum_of_odd_digits + sum_of_even_digits
    return total % 10 == 0


def main():
    card_number = "4111-1111-4555-1142"
    card_translation = str.maketrans({"-": "", " ": ""})
    translated_card_number = card_number.translate(card_translation)

    if verify_card_number(translated_card_number):
        print("VALID!")
    else:
        print("INVALID!")


main()