HKID Validator

hkid.py

#!/usr/bin/env python3
"""Calculate HKID check digit and validate HKID numbers"""

import sys
import operator
from typing import List

def _char_to_int(char: str) -> int:
    """Maps characters in ID to numeric value"""
    try:
        return int(char)
    except ValueError:
        if char == " ":
            return 36
        return ord(char) - 55

def _weighted_sum(id_list: List[int]) -> int:
    weights = range(9, 1, -1)
    return sum(map(operator.mul, id_list, weights))

def _prepare_id(id_str: str) -> str:
    id_str = id_str.upper()

    if ord(id_str[1]) < 58:
        id_str = " " + id_str
    return id_str

def _id_to_ints(id_str: str) -> List[int]:
    output = []
    for char in id_str:
        output.append(_char_to_int(char))
    return output

def _determine_check_digit(total: int) -> str:
    modulus = total % 11
    if modulus == 0:
        return "0"
    if modulus == 1:
        return "A"
    return str(11 - modulus)

def generate_check_digit(id_str: str) -> str:
    """Generat check digit from ID string"""
    id_str = _prepare_id(id_str)
    id_ints = _id_to_ints(id_str)
    total = _weighted_sum(id_ints)
    return _determine_check_digit(total)

def validate_id(id_str: str) -> bool:
    """Given ID and check digit, validate ID"""
    id_str = id_str.replace("(", "").replace(")", "")
    return str(id_str[-1]) == generate_check_digit(id_str[:-1])

def main() -> None:
    """Entry point"""
    id_str = input()
    if validate_id(id_str):
        print("Valid", file=sys.stderr)
    else:
        print("Inalid", file=sys.stderr)
        sys.exit(1)

if __name__ == "__main__":
    main()