"""The maintainer scripts must not stop the agent on an upgrade.

dpkg calls the OLD package's prerm on an upgrade as well as on a removal, and rpm calls it with
an install count. `systemctl disable --now` there stopped the agent on every upgrade and left it
disabled — silently, because the box stays reachable and nothing else notices that check-ins have
ceased (env-dev-01 and env-dev-08, 2026-09-09).
"""

from __future__ import annotations

import shutil
import subprocess
from pathlib import Path

import pytest

PREREMOVE = Path(__file__).resolve().parents[1] / "packaging" / "scripts" / "preremove.sh"


def _run(arg: str, tmp_path: Path) -> list[str]:
    """Run preremove with a fake `systemctl` on PATH and report the calls it made."""
    calls = tmp_path / "systemctl.log"
    fake = tmp_path / "bin"
    fake.mkdir(exist_ok=True)
    (fake / "systemctl").write_text(f'#!/bin/sh\necho "$@" >> {calls}\nexit 0\n')
    (fake / "systemctl").chmod(0o755)
    env = {"PATH": f"{fake}:/usr/bin:/bin"}
    r = subprocess.run(["sh", str(PREREMOVE), arg], env=env, capture_output=True, text=True)
    assert r.returncode == 0, r.stderr
    return calls.read_text().splitlines() if calls.exists() else []


@pytest.mark.skipif(not Path("/run/systemd/system").is_dir(), reason="needs a systemd host to reach the disable branch")
@pytest.mark.parametrize("arg", ["remove", "0"])
def test_a_real_removal_disables_the_units(arg, tmp_path):
    assert any("disable" in c for c in _run(arg, tmp_path))


@pytest.mark.parametrize("arg", ["upgrade", "failed-upgrade", "deconfigure", "1"])
def test_an_upgrade_leaves_the_units_alone(arg, tmp_path):
    assert _run(arg, tmp_path) == []


def test_the_script_is_shell_clean():
    assert shutil.which("sh")
    subprocess.run(["sh", "-n", str(PREREMOVE)], check=True)