# common/private_files/registry.py
from typing import Callable, Tuple, Dict

Guard = Callable[[object, "django.contrib.auth.models.User"], bool]

_REGISTRY: Dict[Tuple[str, str, str], Guard] = {}  # (app_label, model_name, field_name) -> guard

def register(app_label: str, model_name: str, field_name: str, guard: Guard):
    key = (app_label.lower(), model_name.lower(), field_name)
    _REGISTRY[key] = guard

def get_guard(app_label: str, model_name: str, field_name: str) -> Guard | None:
    return _REGISTRY.get((app_label.lower(), model_name.lower(), field_name))