"""Celery task: license expiry checks and alerts."""
import logging
from datetime import date, timedelta

from app.worker import celery_app

logger = logging.getLogger(__name__)


@celery_app.task(name="license.check_expiry")
def check_expiry():
    """Send expiry warning emails for licenses expiring in 30, 14, or 7 days."""
    import os
    from sqlalchemy import create_engine, select, and_
    from sqlalchemy.orm import sessionmaker
    from app.models.license import License, LicenseStatus
    from app.models.school import School
    from app.services.email import send_email

    db_url = os.getenv("DATABASE_URL", "postgresql://postgres:postgres@db:5432/taptrack_hub")
    engine = create_engine(db_url.replace("postgresql+asyncpg://", "postgresql://"), pool_pre_ping=True)
    db = sessionmaker(bind=engine)()
    try:
        today = date.today()
        for days_ahead in [30, 14, 7]:
            target = today + timedelta(days=days_ahead)
            expiring = db.execute(
                select(License).where(
                    and_(License.expires_at == target, License.status == LicenseStatus.active)
                )
            ).scalars().all()
            for lic in expiring:
                school = db.get(School, lic.school_id)
                if school and school.billing_email:
                    send_email(
                        to=school.billing_email,
                        subject=f"[TapTrack Hub] License expires in {days_ahead} days — {school.name}",
                        body=(
                            f"Your TapTrack license for {school.name} expires on {lic.expires_at} "
                            f"({days_ahead} days remaining). Please contact us to renew."
                        ),
                        template_name="email/license_expiry.html",
                        context={
                            "contact_name": school.contact_name or school.name,
                            "school_name": school.name,
                            "license_key": lic.key,
                            "expires_at": str(lic.expires_at),
                            "days_left": days_ahead,
                        },
                        email_type="license_expiry",
                        school_id=school.id,
                    )
        db.commit()
    finally:
        db.close()