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"""Process and signal helpers."""

from __future__ import annotations

import logging
import os
import signal
import sys
import threading

import psutil

logger = logging.getLogger(__name__)


def register_usr_signal():
    parent_process = psutil.Process().parent()

    def signal_handler(sig, frame):
        logger.error("recv usr signal, kill usr signal to parent")
        parent_process.send_signal(signal.SIGUSR1)

    signal.signal(signal.SIGUSR1, signal_handler)


def kill_process_tree(parent_pid, include_parent: bool = True, skip_pid: int = None):
    """Kill the target process and all of its child processes."""
    if threading.current_thread() is threading.main_thread():
        signal.signal(signal.SIGCHLD, signal.SIG_DFL)

    if parent_pid is None:
        parent_pid = os.getpid()
        include_parent = False

    try:
        itself = psutil.Process(parent_pid)
    except psutil.NoSuchProcess:
        return

    children = itself.children(recursive=True)
    for child in children:
        if child.pid == skip_pid:
            continue
        try:
            child.kill()
        except psutil.NoSuchProcess:
            pass

    if include_parent:
        try:
            if parent_pid == os.getpid():
                itself.kill()
                sys.exit(0)

            itself.kill()
            itself.send_signal(signal.SIGQUIT)
        except psutil.NoSuchProcess:
            pass