from __future__ import annotations

import logging
from typing import TYPE_CHECKING

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

from supply_infra.config import get_infra_settings
from supply_infra.pipeline.run_service import submit_pipeline_run
from supply_infra.scheduler.constants import (
    AIGC_PUBLISH_JOB_ID,
    AIGC_PUBLISH_JOB_NAME,
    SUPPLY_PIPELINE_JOB_ID,
    SUPPLY_PIPELINE_JOB_NAME,
)

if TYPE_CHECKING:
    from apscheduler.schedulers.base import BaseScheduler

logger = logging.getLogger(__name__)

_scheduler: BackgroundScheduler | None = None


def submit_scheduled_pipeline() -> dict:
    """Cron callback: create a durable batch and return immediately."""
    return submit_pipeline_run(
        trigger_type="cron",
        trigger_source="scheduler",
    ).to_dict()


def submit_aigc_publish() -> dict:
    """Interval callback: publish any unpublished primary discovery candidates."""
    from supply_infra.scheduler.jobs.publish_videos_from_discovery import (
        publish_videos_from_discovery,
    )

    result = publish_videos_from_discovery(
        skip_published=True,
        any_biz_dt=True,
    )
    logger.info(
        "AIGC publish job finished: success=%s candidates=%s batches=%s failed=%s",
        result.get("success"),
        result.get("candidate_count"),
        result.get("batch_count"),
        result.get("failed_batch_count"),
    )
    return result


def create_scheduler() -> BackgroundScheduler:
    """Create a Scheduler for the daily pipeline and AIGC publish polling."""
    settings = get_infra_settings()
    tz = settings.scheduler_timezone
    scheduler = BackgroundScheduler(timezone=tz)

    scheduler.add_job(
        submit_scheduled_pipeline,
        trigger=CronTrigger(
            hour=settings.scheduler_cron_hour,
            minute=settings.scheduler_cron_minute,
            timezone=tz,
        ),
        id=SUPPLY_PIPELINE_JOB_ID,
        name=SUPPLY_PIPELINE_JOB_NAME,
        replace_existing=True,
        max_instances=1,
        coalesce=True,
        misfire_grace_time=3600,
    )
    scheduler.add_job(
        submit_aigc_publish,
        trigger=IntervalTrigger(
            minutes=settings.scheduler_aigc_publish_interval_minutes,
            timezone=tz,
        ),
        id=AIGC_PUBLISH_JOB_ID,
        name=AIGC_PUBLISH_JOB_NAME,
        replace_existing=True,
        max_instances=1,
        coalesce=True,
        misfire_grace_time=300,
    )

    logger.info(
        "Scheduler configured with %d job(s) | timezone=%s | pipeline_cron=%02d:%02d "
        "| aigc_publish_interval=%dm",
        len(scheduler.get_jobs()),
        tz,
        settings.scheduler_cron_hour,
        settings.scheduler_cron_minute,
        settings.scheduler_aigc_publish_interval_minutes,
    )
    return scheduler


def _log_next_runs(scheduler: BaseScheduler) -> None:
    for job in scheduler.get_jobs():
        # apscheduler 3.x: 在 scheduler.start() 之前，Job.next_run_time 访问会抛 AttributeError
        # 这里用 getattr 兜底，保证启动阶段不因日志而中断。
        next_run_time = getattr(job, "next_run_time", None)
        logger.info("  - %s | next run: %s", job.name, next_run_time)


def start_scheduler() -> BackgroundScheduler | None:
    """Start the independent scheduler process (idempotent)."""
    global _scheduler

    settings = get_infra_settings()
    if not settings.scheduler_enabled:
        logger.warning("Scheduler is disabled (SCHEDULER_ENABLED=false)")
        return None

    if _scheduler is not None and _scheduler.running:
        return _scheduler

    _scheduler = create_scheduler()
    logger.info("Starting scheduler...")
    _scheduler.start()
    _log_next_runs(_scheduler)
    return _scheduler


def stop_scheduler() -> None:
    """Shut down the background scheduler if running."""
    global _scheduler

    if _scheduler is None or not _scheduler.running:
        return

    logger.info("Stopping scheduler...")
    _scheduler.shutdown(wait=False)
    _scheduler = None
    logger.info("Scheduler stopped.")