#!/usr/bin/python3

import argparse
import subprocess
import time

parser = argparse.ArgumentParser(description = 'Run a command on matching udev events')

parser.add_argument('-s', '--subsystem')
parser.add_argument('-m', '--match', action = 'append')

parser.add_argument('command')

args = parser.parse_args()

def process_buf(buf):
    for m in args.match:
        if not m in buf:
            return
    subprocess.run(args.command, shell = True)

cmdline = ['udevadm', 'monitor', '--property']
if args.subsystem:
    cmdline.append('--subsystem-match=' + args.subsystem)

child = subprocess.Popen(cmdline, text = True, stdout = subprocess.PIPE)

try:
    # skip first three lines
    [child.stdout.readline() for i in range(3)]

    buf = []

    while child.poll() is None:
        line = child.stdout.readline().strip()
        if not line:
            process_buf(buf)
            buf.clear()
            continue

        buf.append(line)
finally:
    child.terminate()
    if child.returncode is None:
        time.sleep(0.1)
        child.kill()