"""Storage backend factory."""

from server import config
from server.storage.hf import HuggingFaceStorageManager


_storage_instance = None


def get_storage() -> HuggingFaceStorageManager:
    """Return the configured singleton storage backend."""
    global _storage_instance

    if config.STORAGE_MODE != config.HF_STORAGE_LABEL:
        raise RuntimeError(
            f"Unsupported STORAGE_MODE '{config.STORAGE_MODE}'. "
            "Local storage is disabled. Set STORAGE_MODE=HF."
        )

    if _storage_instance is None:
        _storage_instance = HuggingFaceStorageManager()

    return _storage_instance