"""
Monitors memory usage, notifies and stops/kills the top memory usage process.

Test with:

stress --vm-bytes 7G --vm-hang 0 --vm 1
"""
import argparse
import logging
import time

import config
import lib

logging.basicConfig()
logger = logging.getLogger()


def setup_logging_level(debug=False):
    log_level = logging.DEBUG if debug else logging.ERROR
    logger.setLevel(log_level)
    logger.debug("Debugging enabled")


def parse_args():
    parser = argparse.ArgumentParser()
    parser.add_argument('path', help="Path to monitor")
    parser.add_argument('--debug', dest='debug', action='store_true')
    return parser.parse_args()


def get_available_mem_g():
    mem_available = lib.run_os_command(
        "grep MemAvailable /proc/meminfo | awk '{print $2}'")
    mem_available = int(mem_available)
    mem_available_g = round(mem_available / (1024 ** 2), 1)
    return mem_available_g


def get_top_pid_comm():
    top_pid_comm = lib.run_os_command(
        "ps -eo pid,pmem,comm --sort=-pmem | head -n 2 | awk '{print $1 \" \" $3}' | tail -1")
    return top_pid_comm.split()


def stop_process(pid):
    lib.run_os_command(f"kill -{config.SIGNAL} {pid}")


def main():
    is_low_mem = False
    while True:
        mem_available_g = get_available_mem_g()
        logging.debug(f"Memory Available: {mem_available_g} G")
        top_pid, top_comm = get_top_pid_comm()
        if mem_available_g < config.MEM_MIN_AVAILABLE_G:
            if not is_low_mem:
                message = f"Less than {config.MEM_MIN_AVAILABLE_G}G of memory available. \n\n Sent signal {config.SIGNAL} {top_comm} ({top_pid}) {config.STR_CONT_OPT} \n\n Run 'kill -SIGKILL <PID>' to kill immediately."
                logging.warning(message)
                stop_process(int(top_pid))
                lib.send_notification("Memory Alert", message)
            is_low_mem = True
        else:
            is_low_mem = False

        logging.debug(
            f"Top process by memory usage: PID {top_pid}, Command: {top_comm}")
        time.sleep(config.TIME_SLEEP_MEM_S)


if __name__ == "__main__":
    main()