from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.orm import DeclarativeBase
from sqlalchemy import text

from app.core.config import settings


class Base(DeclarativeBase):
    pass


engine_kwargs = {
    "echo": settings.DEBUG,
}
if not settings.USE_SQLITE:
    engine_kwargs["pool_size"] = 10
    engine_kwargs["max_overflow"] = 20

engine = create_async_engine(
    settings.async_database_url,
    **engine_kwargs,
)

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


async def get_db() -> AsyncSession:
    """Dependency that provides an async 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() -> None:
    """Initialize the database - create all tables."""
    async with engine.begin() as conn:
        # Import all models to register them with Base
        from app.models import user, game, academic, school, progress, payment  # noqa
        await conn.run_sync(Base.metadata.create_all)


async def check_db_connection() -> bool:
    """Check if the database connection is healthy."""
    try:
        async with engine.connect() as conn:
            await conn.execute(text("SELECT 1"))
        return True
    except Exception as e:
        print(f"❌ DB connection error: {e}")
        return False