"""Async database session helpers."""

from collections.abc import AsyncGenerator

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

from app.config import get_settings
from app.models import Base

settings = get_settings()

engine = create_async_engine(
    settings.database_url,
    echo=False,
)

SessionLocal = async_sessionmaker(
    engine,
    expire_on_commit=False,
    class_=AsyncSession,
)


async def init_db() -> None:
    """Create tables if they do not exist."""
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)


async def get_db() -> AsyncGenerator[AsyncSession, None]:
    """Yield a database session."""
    async with SessionLocal() as session:
        yield session