"""
APScheduler setup for background cleanup jobs.

One scheduler instance runs per process.
Jobs run in their own threads (ThreadPoolExecutor).
"""
from __future__ import annotations

import logging

from apscheduler.schedulers.background import BackgroundScheduler
from apscheduler.executors.pool import ThreadPoolExecutor

logger = logging.getLogger(__name__)

_scheduler: BackgroundScheduler | None = None


def get_scheduler() -> BackgroundScheduler:
    global _scheduler
    if _scheduler is None:
        _scheduler = BackgroundScheduler(
            executors={"default": ThreadPoolExecutor(max_workers=2)},
            job_defaults={"coalesce": True, "max_instances": 1},
        )
    return _scheduler


def start_scheduler() -> None:
    sched = get_scheduler()
    if not sched.running:
        sched.start()
        logger.info("APScheduler started")


def stop_scheduler() -> None:
    global _scheduler
    if _scheduler is not None and _scheduler.running:
        _scheduler.shutdown(wait=False)
        logger.info("APScheduler stopped")