"""Database session management for the API gateway."""

from collections.abc import AsyncGenerator

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

from cartsnitch_api.config import settings

engine = create_async_engine(
    settings.database_url,
    echo=False,
    pool_size=10,
    max_overflow=20,
    pool_pre_ping=True,
    pool_recycle=3600,
)
async_session_factory = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)


async def get_db() -> AsyncGenerator[AsyncSession, None]:
    """FastAPI dependency that yields an async DB session."""
    async with async_session_factory() as session:
        yield session


async def dispose_engine() -> None:
    """Dispose the database engine, closing all pooled connections."""
    await engine.dispose()