from typing import AsyncGenerator
from fastapi import Depends
from sqlalchemy.ext.asyncio import AsyncSession
from fastapi_users.db import SQLAlchemyUserDatabase

from ..core.db import async_session_maker, engine
from ..core.base import Base
from ..models.user import User, OAuthAccount

_initialized = False


async def get_async_session() -> AsyncGenerator[AsyncSession, None]:
    global _initialized
    if not _initialized:
        # Lazily ensure tables exist; helpful for test runs without migrations
        async with engine.begin() as conn:
            await conn.run_sync(Base.metadata.create_all)
        _initialized = True
    async with async_session_maker() as session:
        yield session


async def get_user_db(session: AsyncSession = Depends(get_async_session)):
    yield SQLAlchemyUserDatabase(session, User, OAuthAccount)