"""Stop one isolated runner session, including orphaned Mineflayer children."""
from __future__ import annotations

import os
import signal
import subprocess

import psutil


def stop_runner(proc: subprocess.Popen | None, timeout: float = 10) -> None:
    """Only pass children launched with start_new_session=True on POSIX."""
    if proc is None:
        return
    members = []
    if os.name == "posix":
        for child in psutil.process_iter(["pid"]):
            try:
                if os.getpgid(child.pid) == proc.pid:
                    members.append(child)
            except (ProcessLookupError, PermissionError):
                pass
        try:
            os.killpg(proc.pid, signal.SIGTERM)
        except ProcessLookupError:
            return
    elif proc.poll() is None:
        proc.terminate()
    try:
        proc.wait(timeout=timeout)
    except subprocess.TimeoutExpired:
        if os.name != "posix":
            proc.kill()
    finally:
        # The session leader may have exited through os._exit(75), leaving its
        # Node child holding port 3000/3001. Its group still belongs to this
        # runner, even when proc.poll() reports an exit.
        if os.name == "posix":
            try:
                os.killpg(proc.pid, signal.SIGKILL)
            except ProcessLookupError:
                pass
            # Sending a signal is asynchronous. Wait for those exact session
            # members so the next runner cannot race their socket cleanup.
            psutil.wait_procs(members, timeout=2)
    try:
        proc.wait(timeout=5)
    except subprocess.TimeoutExpired:
        pass