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

_scheduler = None


def get_scheduler():
    """获取或创建调度器实例"""
    global _scheduler
    if _scheduler is None:
        _scheduler = BackgroundScheduler()
    return _scheduler


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}"

    # 确保间隔不低于最小值
    interval = max(interval_minutes, config.MIN_FETCH_INTERVAL)

    # 如果任务已存在则更新
    existing = scheduler.get_job(job_id)
    if existing:
        existing.reschedule(trigger=IntervalTrigger(minutes=interval))
        return

    scheduler.add_job(
        fetch_and_store_feed,
        trigger=IntervalTrigger(minutes=interval),
        id=job_id,
        args=[feed_id],
        replace_existing=True,
        misfire_grace_time=300,  # 5分钟容错
        coalesce=True,  # 合并错过的任务
    )


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()


def stop_scheduler():
    """停止调度器"""
    global _scheduler
    if _scheduler and _scheduler.running:
        _scheduler.shutdown(wait=False)
        _scheduler = 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()