import abc
from typing import Iterable

from funcy import curry, identity


class Transformer(abc.ABC):
    @abc.abstractmethod
    def transform(self, obj):
        raise NotImplementedError

    def __call__(self, obj):
        return self._apply(self.transform, obj)

    @staticmethod
    def _must_be_mapped_over(obj):
        return isinstance(obj, Iterable) and not isinstance(obj, dict)

    def _apply(self, func, obj):
        return (curry(map) if self._must_be_mapped_over(obj) else identity)(func)(obj)