"""Shared async database helpers for Celery tasks.

Provides get_async_session() and cleanup_engine() used by both
downloads.py and maintenance.py. This module must not import from
either of those files to avoid circular imports.
"""

from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker

from app.config import get_settings


def get_async_session():
    """Get async session factory for Celery tasks.

    Creates a fresh engine and session factory each time to avoid
    event loop issues when asyncio.run() creates new loops.
    """
    settings = get_settings()
    engine = create_async_engine(settings.async_database_url, echo=False)
    session_factory = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
    return session_factory, engine


async def cleanup_engine(engine):
    """Properly dispose of the async engine."""
    await engine.dispose()