import logging
from datetime import datetime
from pathlib import Path

from apscheduler.schedulers.background import BackgroundScheduler
from sqlalchemy.orm import Session

from config import settings
from database import SecurityEvent, SessionLocal, Share

log = logging.getLogger("droplake.cleanup")


def purge_expired():
    db: Session = SessionLocal()
    try:
        now = datetime.utcnow()

        # Expired shares
        expired = db.query(Share).filter(Share.expires_at < now).all()

        # Burn-after-read shares that have been downloaded
        burnt = (
            db.query(Share)
            .filter(Share.burn_after_read.is_(True), Share.downloaded.is_(True))
            .all()
        )

        # Deduplicate by id
        seen = {}
        for s in expired + burnt:
            seen[s.id] = s
        to_remove = list(seen.values())

        for share in to_remove:
            blob = Path(settings.storage_path) / share.storage_path
            blob.unlink(missing_ok=True)
            db.add(SecurityEvent(event_type="share_cleaned", share_id=share.id))
            db.delete(share)

        if to_remove:
            db.commit()
            log.info("Cleanup: removed %d share(s)", len(to_remove))
    except Exception as exc:
        log.error("Cleanup error: %s", exc)
        db.rollback()
    finally:
        db.close()


def start_scheduler() -> BackgroundScheduler:
    scheduler = BackgroundScheduler(daemon=True)
    scheduler.add_job(
        purge_expired,
        "interval",
        minutes=settings.cleanup_interval_minutes,
        id="cleanup",
        replace_existing=True,
        misfire_grace_time=60,
    )
    scheduler.start()
    log.info("Cleanup scheduler started (every %dm)", settings.cleanup_interval_minutes)
    return scheduler