from typing import AsyncGenerator

from fastapi import Depends
from sqlalchemy.ext.asyncio import AsyncSession

from app.auth.noop import NoOpAuthProvider
from app.auth.provider import AuthProvider
from app.database import get_session_factory
from app.storage.backend import StorageBackend
from app.storage.s3_backend import S3StorageBackend

_storage: StorageBackend | None = None
_auth: AuthProvider | None = None


def get_storage() -> StorageBackend:
    global _storage
    if _storage is None:
        _storage = S3StorageBackend()
    return _storage


def get_auth() -> AuthProvider:
    global _auth
    if _auth is None:
        _auth = NoOpAuthProvider()
    return _auth


async def get_db() -> AsyncGenerator[AsyncSession, None]:
    factory = get_session_factory()
    async with factory() as session:
        async with session.begin():
            yield session