#!/usr/bin/env python3
"""
Parse systemd timeout errors for mission-control-2.service from journalctl.

Captures lines containing "State 'stop-sigterm' timed out" and appends them
to ~/logs/mc2-timeout.log with ISO timestamps.

Permission errors are handled gracefully.
"""

import os
import subprocess
from datetime import datetime, timezone
from pathlib import Path


LOG_DIR = Path.home() / "logs"
LOG_FILE = LOG_DIR / "mc2-timeout.log"
SERVICE_NAME = "mission-control-2.service"
SEARCH_PATTERN = "State 'stop-sigterm' timed out"
JOURNALCTL_LIMIT = 1000


def ensure_log_dir() -> None:
    """Create log directory if it doesn't exist."""
    LOG_DIR.mkdir(parents=True, exist_ok=True)


def get_timeout_entries() -> list[str]:
    """Run journalctl and return lines matching the timeout pattern."""
    cmd = [
        "journalctl",
        "-u", SERVICE_NAME,
        "--no-pager",
        "-n", str(JOURNALCTL_LIMIT),
    ]
    try:
        result = subprocess.run(
            cmd,
            capture_output=True,
            text=True,
            timeout=30,
        )
    except subprocess.TimeoutExpired:
        print("journalctl timed out")
        return []
    except PermissionError:
        print("Permission denied: journalctl requires access to system logs")
        return []

    if result.returncode != 0:
        if "Permission denied" in result.stderr:
            print("Permission denied: journalctl requires access to system logs")
        else:
            print(f"journalctl failed: {result.stderr.strip()}")
        return []

    return [
        line
        for line in result.stdout.splitlines()
        if SEARCH_PATTERN in line
    ]


def write_to_log(entries: list[str]) -> int:
    """Append entries to log file with ISO timestamps. Returns count written."""
    ensure_log_dir()

    timestamp = datetime.now(timezone.utc).isoformat()
    written = 0

    with LOG_FILE.open("a", encoding="utf-8") as f:
        for entry in entries:
            f.write(f"[{timestamp}] {entry}\n")
            written += 1

    return written


def main() -> None:
    entries = get_timeout_entries()
    if not entries:
        print("No timeout entries found.")
        return

    count = write_to_log(entries)
    print(f"Appended {count} timeout entry/ies to {LOG_FILE}")


if __name__ == "__main__":
    main()