# Database Connection and Session Management

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


# Create async engine
engine = create_async_engine(
    settings.DATABASE_URL,
    echo=settings.DEBUG,
    poolclass=NullPool if "sqlite" in settings.DATABASE_URL else None,
    pool_pre_ping=True,
)

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


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


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


async def close_db():
    """Close database connections"""
    await engine.dispose()