#!/usr/bin/env python3

"""A simple utility to unpickle some code, run it, and pickle the
results.
"""

import os
import platform
import signal
import sys
import threading
import time

import cloudpickle  # type: ignore
import psutil  # type: ignore

import bootstrap
import config
from thread_utils import background_thread


cfg = config.add_commandline_args(
    f"Remote Worker ({__file__})",
    "Helper to run pickled code remotely and return results",
)
cfg.add_argument(
    '--code_file',
    type=str,
    required=True,
    metavar='FILENAME',
    help='The location of the bundle of code to execute.'
)
cfg.add_argument(
    '--result_file',
    type=str,
    required=True,
    metavar='FILENAME',
    help='The location where we should write the computation results.'
)


@background_thread
def watch_for_cancel(terminate_event: threading.Event) -> None:
    p = psutil.Process(os.getpid())
    while True:
        saw_sshd = False
        ancestors = p.parents()
        for ancestor in ancestors:
            name = ancestor.name()
            if 'ssh' in name or 'Ssh' in name:
                saw_sshd = True
                break

        if not saw_sshd:
            os.system('pstree')
            os.kill(os.getpid(), signal.SIGTERM)
        if terminate_event.is_set():
            return
        time.sleep(1.0)


@bootstrap.initialize
def main() -> None:
    hostname = platform.node()

    # Windows-Linux is retarded.
    if hostname != 'VIDEO-COMPUTER':
        (thread, terminate_event) = watch_for_cancel()

    in_file = config.config['code_file']
    out_file = config.config['result_file']

    with open(in_file, 'rb') as rb:
        serialized = rb.read()

    fun, args, kwargs = cloudpickle.loads(serialized)
    ret = fun(*args, **kwargs)

    serialized = cloudpickle.dumps(ret)
    with open(out_file, 'wb') as wb:
        wb.write(serialized)

    # Windows-Linux is retarded.
    if hostname != 'VIDEO-COMPUTER':
        terminate_event.set()
        thread.join()
    sys.exit(0)


if __name__ == '__main__':
    main()