from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.orm import declarative_base
from app.config import settings

# Create async engine with tuned pool (AW-7)
engine = create_async_engine(
    settings.DATABASE_URL,
    echo=False,
    future=True,
    pool_size=10,
    max_overflow=5,
    pool_pre_ping=True,
    pool_recycle=1800,
)

# Create async session factory
AsyncSessionLocal = async_sessionmaker(
    engine,
    class_=AsyncSession,
    expire_on_commit=False,
    autocommit=False,
    autoflush=False
)

# Base class for models
Base = declarative_base()


# Dependency to get database session
async def get_db() -> AsyncSession:
    async with AsyncSessionLocal() as session:
        try:
            yield session
        except Exception:
            await session.rollback()
            raise