import random

user_input = None

card_number = None
card_pin = None


def main_menu():
    print('1. Create an account')
    print('2. Log into an account')
    print('0. Exit')
    print()

    global user_input
    user_input = int(input())


def create_account():
    if user_input == 1:
        print("Your card has been created")

        global card_number
        card_number = random.randint(4000001111111111, 4000009999999999)

        print("This is your card number: ")
        print(int(card_number))

        verify_card_number(card_number)

        global card_pin

        card_pin = random.randint(1001, 9999)

        print("Your card pin: ")
        print(int(card_pin))
        print()

        main_menu


def log_into_account():
    if user_input == 2:
        print("Enter your card number: ")
        user_entered_card_number = int(input())

        print("Enter your PIN ")
        user_entered_pin = int(input())

        compare_informations(user_entered_card_number, user_entered_pin)

        print()


def compare_informations(user_entered_card_number, user_entered_pin):
    if user_entered_card_number == card_number and user_entered_pin == card_pin:
        print("You have successfully logged in!")
        login_menu()
    else:
        print("Wrong card number or PIN!")
        print()
        main_menu()


def exit_program():
    if user_input == 0:
        exit()


def verify_card_number(card_number):
    check_sum = card_number % 10
    card_number = str(card_number)[:-1]
    card_number_list = [int(x) for x in str(card_number)]
    for i in range(len(card_number_list)):
        if i % 2 == 0:
            card_number_list[i] = card_number_list[i] + card_number_list[i]

    for j in range(len(card_number_list)):
        if 9 < card_number_list[j]:
            card_number_list[j] = card_number_list[j] - 9

    strings = [str(k) for k in card_number_list]
    string_of_num = "".join(strings)
    orig_card_number = int(string_of_num)

    # Sum of digits
    sum_of_digit = 0
    for digit in str(orig_card_number):
        sum_of_digit += int(digit)

    all_sum = sum_of_digit + check_sum

    if all_sum % 10 == 0:
        return str(orig_card_number)


def login_menu():
    print("1. Balance")
    print("2. Logout")
    print("0. Exit")
    print()

    user_input_login_menu = int(input())
    if user_input_login_menu == 1:
        print("Balance: 0")
        print()
    elif user_input_login_menu == 2:
        print("You have successfully logged out")
        print()
        main_menu()
    elif user_input_login_menu == 0:
        print("Bye!")
        exit()


while True:
    main_menu()
    create_account()
    log_into_account()
    exit_program()