app/tasks/expiry_check_task.py

"""Author RAG Chatbot SaaS — Subscription Expiry Check Task.

Runs daily at 8am UTC. Sends warning emails at:
- 7 days before expiry
- 1 day before expiry
"""

import structlog
from app.tasks.celery_app import celery_app

logger = structlog.get_logger(__name__)


@celery_app.task(name="app.tasks.expiry_check_task.check_expiring_subscriptions")
def check_expiring_subscriptions():
    """Check all active subscriptions for upcoming expiry and send alerts."""
    import asyncio
    asyncio.run(_run())


async def _run():
    from datetime import datetime, timedelta, timezone
    from sqlalchemy import select
    from app.dependencies import _get_session_factory
    from app.models.client_access import ClientAccess
    from app.models.user import User
    from app.services.email_service import EmailService

    email = EmailService()
    now = datetime.now(timezone.utc).replace(tzinfo=None)  # SQLite stores naive datetimes
    warning_days = [7, 1]

    async with _get_session_factory()() as db:
        result = await db.execute(
            select(ClientAccess, User)
            .join(User, User.id == ClientAccess.author_id)
            .where(
                ClientAccess.is_revoked == False,
                ClientAccess.expires_at > now,
                User.notify_subscription_expiry == True,
            )
        )
        records = result.all()

        sent = 0
        for access, user in records:
            expires = access.expires_at.replace(tzinfo=None) if access.expires_at.tzinfo else access.expires_at
            days_left = (expires - now).days
            if days_left in warning_days:
                try:
                    email.send_subscription_expiry_warning(
                        to=user.email,
                        name=user.full_name or user.email,
                        days_remaining=days_left,
                        expires_at=access.expires_at.strftime("%B %d, %Y"),
                    )
                    sent += 1
                except Exception as e:
                    logger.warning("Expiry warning email failed", user_id=user.id, error=str(e))

    logger.info("Expiry check complete", warnings_sent=sent)