"""Фоновый asyncio-цикл сканирования stale heartbeat (в процессе sac-api)."""

from __future__ import annotations

import asyncio
import logging

from app.config import get_settings
from app.database import SessionLocal
from app.services.host_silence_scan import dispatch_host_silence_notifications, run_host_silence_scan

logger = logging.getLogger("sac.host_silence_scan")


async def host_silence_scan_loop(stop_event: asyncio.Event) -> None:
    settings = get_settings()
    interval_sec = max(60, int(settings.sac_host_silence_scan_interval_minutes) * 60)
    logger.info(
        "host_silence background scan enabled (interval=%s min, stale=%s min)",
        settings.sac_host_silence_scan_interval_minutes,
        settings.sac_heartbeat_stale_minutes,
    )
    while not stop_event.is_set():
        try:
            await asyncio.to_thread(_run_scan_once)
        except Exception:
            logger.exception("host_silence background scan error")
        try:
            await asyncio.wait_for(stop_event.wait(), timeout=interval_sec)
        except asyncio.TimeoutError:
            continue


def _run_scan_once() -> None:
    db = SessionLocal()
    try:
        results = run_host_silence_scan(db)
        notified = dispatch_host_silence_notifications(db, results)
        db.commit()
        if results:
            logger.info(
                "host_silence background: stale=%s created=%s notified=%s",
                len(results),
                sum(1 for r in results if r.created),
                notified,
            )
    except Exception:
        db.rollback()
        raise
    finally:
        db.close()