card_gen.py

from itertools import product


checker = [
    "2", "1", "2", "1", "2", "1", "2", "1",
    "2", "1", "2", "1", "2", "1", "2", "1"
]


def sum_card_digits(card_num):
    total = 0
    for n in card_num:
        total += int(n)
    return total


def valid_card(cards):
    print("Validating...")
    result = []
    for card in cards:
        if luhn_valid(card) and (int(card) % 123457) == 0:
            result.append(card)
    return result


def build_card_nums(card_num, missing_digits, perms):
    print("Building numbers...")
    result = []
    for perm in perms:
        p = "".join(map(str, perm))
        c = card_num.replace("*"*missing_digits, p)
        result.append(c)
    return result


def possible_perms(init_sum, missing_digits):
    print("Generating permutations...")
    result = []
    x = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
    for p in product(x, repeat=missing_digits):
        result.append(p)

    return result


def luhn_sum(num):
    total = 0
    for i, n in enumerate(num):
        if n == "*":
            continue
        cost = int(n) * int(checker[i])
        if cost > 9:
            cost -= 9
        total += cost

    return total


def luhn_valid(num):
    total = luhn_sum(num)
    if total % 10 == 0:
        return True
    return False


def main():
    card_num = "543210******1234"
    missing_digits = card_num.count("*")

    init_sum = luhn_sum(card_num)
    perms = possible_perms(init_sum, missing_digits)

    possible_cards = build_card_nums(card_num, missing_digits, perms)

    result = valid_card(possible_cards)

    print("--------------------------")
    print("Found {} valid card(s)".format(len(result)))
    print("Card Number:{}".format(result))
    print("--------------------------")


if __name__ == "__main__":
    main()