#!/usr/bin/env python3
"""Exercise the independent recovery task after a real systemd service stop."""

from __future__ import annotations

import os
from pathlib import Path
import shutil
import subprocess
import time
from uuid import uuid4


def run(*args: str) -> subprocess.CompletedProcess[str]:
    return subprocess.run(args, check=True, capture_output=True, text=True, timeout=30)


def main() -> int:
    if os.geteuid() != 0 or not Path("/run/systemd/system").is_dir():
        raise RuntimeError("real systemd lifecycle test requires root on a systemd host")
    token = uuid4().hex[:12]
    directory_name = f"matrix-kernel-recovery-test-{token}"
    main_unit = f"{directory_name}-main"
    task_unit = f"{directory_name}-task"
    runtime = Path("/run") / directory_name
    if runtime.exists():
        raise RuntimeError("isolated runtime directory already exists")
    try:
        run("systemd-run", "--quiet", f"--unit={main_unit}",
            f"--property=RuntimeDirectory={directory_name}",
            "--property=RuntimeDirectoryPreserve=yes", "/bin/sleep", "120")
        for _ in range(30):
            if runtime.is_dir():
                break
            time.sleep(0.1)
        else:
            raise RuntimeError("temporary service did not create its runtime directory")
        if run("systemctl", "show", main_unit, "--property=RuntimeDirectoryPreserve", "--value").stdout.strip() != "yes":
            raise RuntimeError("temporary service did not enable runtime preservation")
        run("systemctl", "stop", main_unit)
        if not runtime.is_dir():
            raise RuntimeError("systemd removed the runtime directory after service stop")
        proof = runtime / "independent-task.txt"
        run("systemd-run", "--quiet", "--wait", "--collect", f"--unit={task_unit}",
            "/usr/bin/python3", "-c",
            "from pathlib import Path; import sys; Path(sys.argv[1]).write_text('ok', encoding='ascii')",
            str(proof))
        if proof.read_text(encoding="ascii") != "ok":
            raise RuntimeError("independent task did not survive the main service stop")
        print("real systemd recovery lifecycle passed")
        return 0
    finally:
        subprocess.run(["systemctl", "stop", main_unit], check=False, capture_output=True, timeout=15)
        if runtime.is_dir() and runtime.parent == Path("/run") and runtime.name == directory_name:
            shutil.rmtree(runtime)


if __name__ == "__main__":
    raise SystemExit(main())