from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy import create_engine
from sqlalchemy.orm import DeclarativeBase, sessionmaker
from app.core.config import settings

# Async engine for FastAPI
engine = create_async_engine(
    settings.database_url,
    echo=settings.environment == "development",
    pool_size=10,
    max_overflow=20,
)

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

# Sync engine for Celery workers (Celery + asyncio don't mix well)
# Convert async URL to sync: postgresql+asyncpg:// → postgresql+psycopg2://
sync_url = settings.database_url.replace("postgresql+asyncpg://", "postgresql+psycopg2://")
sync_engine = create_engine(
    sync_url,
    echo=False,
    pool_size=5,
    max_overflow=10,
    pool_pre_ping=True,
)

SyncSessionLocal = sessionmaker(sync_engine, expire_on_commit=False)


class Base(DeclarativeBase):
    pass


async def get_db():
    async with AsyncSessionLocal() as session:
        try:
            yield session
            await session.commit()
        except Exception:
            await session.rollback()
            raise
        finally:
            await session.close()