"""SQLAlchemy async engine and session factory."""

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

from shared.config import BaseConfig


def create_db(config: BaseConfig) -> tuple:
    """Create an async engine and session factory from the given config.

    Returns a ``(engine, session_factory)`` tuple.
    """
    engine = create_async_engine(
        config.database_url,
        echo=config.log_level == "DEBUG",
    )
    session_factory = async_sessionmaker(
        engine,
        class_=AsyncSession,
        expire_on_commit=False,
    )
    return engine, session_factory