from typing import AsyncGenerator
from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker, AsyncSession
from inferroute.config import settings
from inferroute.models import Base

# Create async engine with parameters appropriate for the database backend
engine_args = {"echo": False}
if "sqlite" not in settings.DATABASE_URL:
    engine_args["pool_size"] = 10
    engine_args["max_overflow"] = 20

engine = create_async_engine(
    settings.DATABASE_URL,
    **engine_args
)

# Async session factory
async_session = async_sessionmaker(
    bind=engine,
    class_=AsyncSession,
    expire_on_commit=False
)

async def init_db() -> None:
    """Initialize database tables."""
    async with engine.begin() as conn:
        # For development ease, we auto-create the schema
        await conn.run_sync(Base.metadata.create_all)

async def get_db() -> AsyncGenerator[AsyncSession, None]:
    """Dependency for getting database sessions."""
    async with async_session() as session:
        try:
            yield session
            await session.commit()
        except Exception:
            await session.rollback()
            raise
        finally:
            await session.close()