import typing as t

from enum import EnumMeta


_extra_values: t.Dict[str, t.Dict[str, t.Any]] = {}


def register_value(
    cl_str: str,
    name: str,
    value: t.Any,
) -> None:
    _extra_values[cl_str] = _extra_values.get(cl_str, {})
    _extra_values[cl_str][name] = value


class ExtendableEnum(EnumMeta):
    def __new__(
        metacl,
        name: str,
        bases: t.Tuple[t.Type],
        classdict: t.Dict[str, t.Any],
    ) -> "ExtendableEnum":
        extra_vals = _extra_values.get(name)

        if extra_vals is not None:
            for extra_name, extra_val in list(extra_vals.items()):
                if extra_name in classdict:
                    raise AttributeError(
                        "Enumeration extensions cannot override existing "
                        "enumeration members")
                else:
                    classdict[extra_name] = extra_val

        return super(ExtendableEnum, metacl).__new__(metacl, name,
                                                     bases, classdict)
