import os

import netifaces


def get_device_name() -> str:
    if 'INTERFACE' not in os.environ:
        print("[Error] \"INTERFACE\" not found in your environment variables")
        print("         Please specify your network interface")
        exit(0)

    return os.environ['INTERFACE']


def get_mac_address() -> bytes:
    return bytes(list(map(lambda i: int(i, 16), netifaces.ifaddresses(
        get_device_name())[netifaces.AF_LINK][0]["addr"].split(":"))))


mac_address = get_mac_address()

broadcast_address = b'\xff\xff\xff\xff\xff\xff'