import time
from pathlib import Path
from apscheduler.schedulers.asyncio import AsyncIOScheduler

_scheduler: AsyncIOScheduler | None = None


def _cleanup_old_files(upload_dir: Path, output_dir: Path, max_age_seconds: int = 3600) -> None:
    """Delete MP3 files older than max_age_seconds. Runs in a thread pool."""
    now = time.time()

    for f in upload_dir.glob("*.mp3"):
        try:
            if now - f.stat().st_mtime > max_age_seconds:
                f.unlink(missing_ok=True)
        except OSError:
            pass

    for f in output_dir.rglob("*.mp3"):
        try:
            if now - f.stat().st_mtime > max_age_seconds:
                f.unlink(missing_ok=True)
        except OSError:
            pass

    # Remove empty per-job output directories left after file cleanup.
    for d in sorted(output_dir.rglob("*"), reverse=True):
        if not d.is_dir():
            continue
        try:
            next(d.iterdir())
        except StopIteration:
            d.rmdir()
        except OSError:
            pass


def start_cleanup_scheduler(upload_dir: Path, output_dir: Path) -> None:
    global _scheduler
    _scheduler = AsyncIOScheduler()
    _scheduler.add_job(
        _cleanup_old_files,
        "interval",
        minutes=15,
        args=[upload_dir, output_dir],
        executor="default",
    )
    _scheduler.start()


def stop_cleanup_scheduler() -> None:
    global _scheduler
    if _scheduler is not None:
        _scheduler.shutdown(wait=False)
        _scheduler = None