from typing import AsyncGenerator
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.orm import DeclarativeBase
from app.config import settings


engine = create_async_engine(
    settings.DATABASE_URL,
    echo=True,
    connect_args={"check_same_thread": False} if "sqlite" in settings.DATABASE_URL else {}
)

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


class Base(DeclarativeBase):
    pass


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


async def init_db():
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)