"""APScheduler setup for periodic checks."""
from apscheduler.schedulers.background import BackgroundScheduler

from app.checker import run_check
from app.models import get_all_services_for_scheduler


def _run_all_checks():
    """Run checks for all registered services."""
    services = get_all_services_for_scheduler()
    for svc in services:
        run_check(svc["id"], svc["target"], svc["protocol"])


def start_scheduler():
    """Start the background scheduler. Uses interval jobs per service."""
    scheduler = BackgroundScheduler()
    _scheduled_ids = set()

    def sync_jobs():
        """Only add/remove jobs when the service list changes."""
        nonlocal _scheduled_ids
        services = get_all_services_for_scheduler()
        current_ids = {svc["id"] for svc in services}
        svc_by_id = {svc["id"]: svc for svc in services}

        # Remove jobs for deleted services
        for sid in _scheduled_ids - current_ids:
            job_id = f"service_{sid}"
            if scheduler.get_job(job_id):
                scheduler.remove_job(job_id)
            _scheduled_ids.discard(sid)

        # Add jobs only for services that don't have one yet
        for sid in current_ids:
            if sid in _scheduled_ids:
                continue
            svc = svc_by_id[sid]
            job_id = f"service_{sid}"
            interval = max(10, svc["interval_seconds"])
            scheduler.add_job(
                run_check,
                "interval",
                seconds=interval,
                id=job_id,
                args=[svc["id"], svc["target"], svc["protocol"]],
            )
            _scheduled_ids.add(sid)

    # Run checks immediately on startup, then schedule
    _run_all_checks()
    sync_jobs()

    # Sync job list every 60 seconds (only adds/removes when services change)
    scheduler.add_job(sync_jobs, "interval", seconds=60, id="sync_jobs")

    scheduler.start()