"""APScheduler 기반 백그라운드 잡.

- 16:00 KST  : daily_batch
- (Phase 4) 16:30: 모델 추론, 02:00 일요일: 주간 재학습

FastAPI 기동 시점에 lifespan 으로 start, 종료 시 shutdown.
"""
from __future__ import annotations

import logging

from apscheduler.schedulers.background import BackgroundScheduler
from apscheduler.triggers.cron import CronTrigger
from pytz import timezone

from app.pipelines.daily_batch import run_daily_batch

logger = logging.getLogger(__name__)
KST = timezone("Asia/Seoul")

_scheduler: BackgroundScheduler | None = None


def start_scheduler() -> BackgroundScheduler:
    global _scheduler
    if _scheduler:
        return _scheduler
    _scheduler = BackgroundScheduler(timezone=KST)
    _scheduler.add_job(
        run_daily_batch,
        CronTrigger(hour=16, minute=0, timezone=KST),
        id="daily_batch_16",
        replace_existing=True,
        max_instances=1,
    )
    _scheduler.start()
    logger.info("scheduler started (daily_batch @ 16:00 KST)")
    return _scheduler


def shutdown_scheduler() -> None:
    global _scheduler
    if _scheduler:
        _scheduler.shutdown(wait=False)
        _scheduler = None
        logger.info("scheduler stopped")