#!/usr/bin/env python3
"""
Test KrautStatus's UDP API for a given IP and (optionally) port.
"""

import argparse
import ipaddress
import socket

def port(string):
    "Convert string to an unsigend integer that is a valid port number"
    port = int(string)

    if port < 0 or port > 65535:
        raise ValueError()

    return port

def main():
    parser = argparse.ArgumentParser(__doc__)

    parser.add_argument("ip",
                        metavar="IP",
                        type=ipaddress.ip_address,
                        help="IP address of the KrautStatus Arduino")

    parser.add_argument("port",
                        nargs="?",
                        metavar="PORT",
                        default=12345,
                        type=port,
                        help="port that the KrautStatus Arduino listens to")

    args = parser.parse_args()


    receiver = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    receiver.bind(('0.0.0.0', args.port))
    print(f'Listening on 0.0.0.0:{args.port}.')

    sender = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    # We do not use \0 or \1 here, so that we do not trigger ourselves when
    # testing the script locally (127.0.0.1)
    sender.sendto(b'\2', (str(args.ip), args.port))
    print(f'Sent null byte to {args.ip}:{args.port}.')

    while True:
        status, address = receiver.recvfrom(1)

        if not address[0] == str(args.ip):
            continue

        if status[0] == 0:
            print('Responded: door closed')
            return

        if status[0] == 1:
            print('Resondend: door open')
            return

if __name__ == "__main__":
    main()