"""Install and remove the systemd user service without touching recordings."""

from __future__ import annotations

import os
import subprocess
import tempfile
from collections.abc import Callable
from pathlib import Path


UNIT_NAME = "mic-clipper.service"


def render_unit(python: Path, project_root: Path) -> str:
    return f"""[Unit]
Description=Offline voice-activated microphone clip recorder
Wants=pipewire.service wireplumber.service pipewire-pulse.service
After=pipewire.service wireplumber.service pipewire-pulse.service
StartLimitIntervalSec=300
StartLimitBurst=10

[Service]
Type=simple
WorkingDirectory={project_root}
Environment=PYTHONPATH={project_root / 'src'}
ExecStart={python} -m mic_clipper.cli run
Restart=on-failure
RestartSec=5s
RestartSteps=5
RestartMaxDelaySec=60s
NoNewPrivileges=yes
PrivateTmp=yes
UMask=0077

[Install]
WantedBy=default.target
"""


def install(
    *,
    unit_path: Path,
    python: Path,
    project_root: Path,
    dry_run: bool = False,
    run_command: Callable[[list[str]], object] | None = None,
) -> list[list[str]]:
    commands = [
        ["systemctl", "--user", "daemon-reload"],
        ["systemctl", "--user", "enable", "--now", UNIT_NAME],
    ]
    if dry_run:
        return commands
    unit_path.parent.mkdir(mode=0o700, parents=True, exist_ok=True)
    _write_private(unit_path, render_unit(python, project_root))
    runner = run_command or _run_command
    for command in commands:
        runner(command)
    return commands


def uninstall(
    *,
    unit_path: Path,
    run_command: Callable[[list[str]], object] | None = None,
) -> list[list[str]]:
    if not unit_path.exists():
        return []
    commands = [
        ["systemctl", "--user", "disable", "--now", UNIT_NAME],
        ["systemctl", "--user", "daemon-reload"],
    ]
    runner = run_command or _run_command
    for command in commands[:1]:
        runner(command)
    unit_path.unlink()
    runner(commands[1])
    return commands


def status() -> int:
    return subprocess.run(
        ["systemctl", "--user", "status", UNIT_NAME], check=False
    ).returncode


def _write_private(path: Path, content: str) -> None:
    with tempfile.NamedTemporaryFile(
        "w", encoding="utf-8", dir=path.parent, prefix=f".{path.name}.", delete=False
    ) as temporary:
        temporary.write(content)
        temporary.flush()
        os.fchmod(temporary.fileno(), 0o600)
        temporary_path = Path(temporary.name)
    os.replace(temporary_path, path)
    os.chmod(path, 0o600)


def _run_command(command: list[str]) -> None:
    subprocess.run(command, check=True)