Juicebox checksum calculator

#!/usr/bin/env python3

import sys

ALPHABET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"


def base35encode(number: int) -> str:
    base35 = ""

    while number > 1:
        number, i = divmod(number, 35)
        if i == 24:
            i = 35
        base35 = base35 + ALPHABET[i]

    return base35


def base35decode(number: str) -> int:
    decimal = 0
    for i, s in enumerate(reversed(number)):
        decimal += ALPHABET.index(s) * (35**i)
    return decimal


def crc(data: str) -> int:
    h = 0
    for s in data:
        h ^= (h << 5) + (h >> 2) + ord(s)
        h &= 0xFFFF
    return h


def _main():
    data = sys.argv[1]
    check = data[-4:-1]
    data = data[:-5]

    decimal = base35decode(check)

    total = crc(data)

    print(f"Check:  \t{check}")
    print(f"Decimal: \t{decimal}")
    print()
    print(f"CRC:  \t\t{total}")
    print(f"Base35: \t{base35encode(total)}")
    print()


if __name__ == "__main__":
    _main()