#!/usr/bin/env python3.6
from sys import argv, exit


def start_stop(process):
    """Starts/Stops a process

    It stops the process that is passed to it by killing it's process ID. If no
    process ID is found, then the process is started.
    """
    from subprocess import CalledProcessError, check_output, os, signal

    root = 0            # root always runs with a guid of 0
    user = os.getuid()  # who is running this script

    # Ensure that we are running as root
    if user == root:
        # Attempt to kill the process
        try:
            pid_list = map(int, check_output(["pidof", process]).split())
            for pid in pid_list:
                os.kill(pid, signal.SIGKILL)
                print(f'TERMINATED: [{pid}] {process}')
        except CalledProcessError:
            # If the process is not running, start it
            print(f'STARTING: {process}:')
            os.system(process)
    else:
        usage()


def usage():
    # Let the user know that this script needs to run as root
    print('Use sudo to run this script!\n')
    if len(argv) > 1:
        print(f'  sudo {argv[0]} {argv[1]}\n')
    else:
        print(f'  sudo {argv[0]}\n')
    exit()


def main():
    """Run as a script

    Takes the commandline argument for the process to start/stop.
    """
    if len(argv) == 1:
        usage()
    else:
        start_stop_proc(argv[1])


if __name__ == '__main__':
    # Start the script if it is being ran from the command line
    start_stop("motion")