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

engine = create_async_engine(
    settings.DATABASE_URL,
    echo=False, # Termelésben ne legyen True a log-áradat miatt
    future=True,
    pool_size=30,       # Megemelve a Researcher 15-20 szála miatt
    max_overflow=20,    # Extra rugalmasság csúcsidőben
    pool_pre_ping=True  # Megakadályozza a "Server closed connection" hibákat
)

AsyncSessionLocal = async_sessionmaker(
    engine, 
    class_=AsyncSession, 
    expire_on_commit=False, 
    autoflush=False
)

SessionLocal = AsyncSessionLocal 

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