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

_flask_app = None

scheduler = BackgroundScheduler(
    job_defaults={"coalesce": True, "max_instances": 1},
    timezone="UTC",
)


def init_scheduler(flask_app):
    global _flask_app
    _flask_app = flask_app
    if not scheduler.running:
        scheduler.start()


def _execute_job(job_id):
    with _flask_app.app_context():
        from jobs.ynh_backup import execute_job
        execute_job(job_id)


def schedule_job(job):
    job_key = f"job_{job.id}"
    try:
        trigger = CronTrigger.from_crontab(job.cron_expr)
    except Exception:
        return
    if scheduler.get_job(job_key):
        scheduler.reschedule_job(job_key, trigger=trigger)
    else:
        scheduler.add_job(
            func=_execute_job,
            trigger=trigger,
            id=job_key,
            kwargs={"job_id": job.id},
            replace_existing=True,
        )


def remove_job(job_id):
    job_key = f"job_{job_id}"
    if scheduler.get_job(job_key):
        scheduler.remove_job(job_key)


def get_next_run(job_id):
    job_key = f"job_{job_id}"
    apsjob = scheduler.get_job(job_key)
    if apsjob and apsjob.next_run_time:
        return apsjob.next_run_time
    return None