"""APScheduler 定时任务管理"""
import logging
from apscheduler.schedulers.background import BackgroundScheduler
from apscheduler.triggers.interval import IntervalTrigger
from rss_fetcher import fetch_and_store_feed
import config

logger = logging.getLogger(__name__)

_scheduler = None


def get_scheduler():
    """获取或创建调度器实例"""
    global _scheduler
    if _scheduler is None:
        _scheduler = BackgroundScheduler(
            job_defaults={
                "coalesce": True,
                "max_instances": 1,
                "misfire_grace_time": 300,
            },
            logger=logger,
        )
    return _scheduler


def _safe_fetch(feed_id: int):
    """安全包装：防止单个 job 异常导致调度器线程崩溃"""
    try:
        fetch_and_store_feed(feed_id)
    except Exception as e:
        logger.error(f"调度抓取失败 feed_id={feed_id}: {e}")


def add_feed_job(feed_id: int, interval_minutes: int):
    """为指定 RSS 源添加定时抓取任务"""
    scheduler = get_scheduler()
    job_id = f"fetch_feed_{feed_id}"
    interval = max(interval_minutes, config.MIN_FETCH_INTERVAL)

    existing = scheduler.get_job(job_id)
    if existing:
        existing.reschedule(trigger=IntervalTrigger(minutes=interval))
        return

    scheduler.add_job(
        _safe_fetch,
        trigger=IntervalTrigger(minutes=interval),
        id=job_id,
        args=[feed_id],
        replace_existing=True,
    )


def remove_feed_job(feed_id: int):
    """移除指定 RSS 源的定时任务"""
    scheduler = get_scheduler()
    job_id = f"fetch_feed_{feed_id}"
    try:
        scheduler.remove_job(job_id)
    except Exception:
        pass


def start_scheduler():
    """启动调度器"""
    scheduler = get_scheduler()
    if not scheduler.running:
        scheduler.start()
        logger.info("调度器已启动")


def stop_scheduler():
    """停止调度器"""
    global _scheduler
    if _scheduler and _scheduler.running:
        _scheduler.shutdown(wait=False)
        _scheduler = None


def scheduler_status():
    """获取调度器状态（供健康检查使用）"""
    scheduler = get_scheduler()
    if not scheduler.running:
        return {"running": False, "jobs": 0}
    jobs = scheduler.get_jobs()
    return {"running": True, "jobs": len(jobs)}


def get_feed_next_run(feed_id: int):
    """获取指定 RSS 源的下一次抓取时间"""
    scheduler = get_scheduler()
    if not scheduler.running:
        return None
    job = scheduler.get_job(f"fetch_feed_{feed_id}")
    return job.next_run_time if job else None


def init_feed_jobs(db):
    """从数据库加载所有活跃 RSS 源并注册定时任务"""
    from models import Feed
    feeds = db.query(Feed).filter(Feed.is_active == True).all()
    for feed in feeds:
        add_feed_job(feed.id, feed.fetch_interval_minutes or config.DEFAULT_FETCH_INTERVAL)
    start_scheduler()
    logger.info(f"已注册 {len(feeds)} 个定时抓取任务")