"""Mixin classes can be inherited by other classes for additional functionality. """
import shopify.resources


class Countable(object):

    @classmethod
    def count(cls, _options=None, **kwargs):
        if _options is None:
            _options = kwargs
        return int(cls.get("count", **_options))


""" Metafields provide custom fields to entities such as products, orders and customers.
Example metafields: (namespace = "Instructions", key = "wash", value = "warm water")
"""


class Metafields(object):

    def metafields(self, _options=None, **kwargs):
        if _options is None:
            _options = kwargs
        return shopify.resources.Metafield.find(resource=self.__class__.plural, resource_id=self.id, **_options)

    def metafields_count(self, _options=None, **kwargs):
        if _options is None:
            _options = kwargs
        return int(self.get("metafields/count", **_options))

    def add_metafield(self, metafield):
        if self.is_new():
            raise ValueError("You can only add metafields to a resource that has been saved")

        metafield._prefix_options = dict(resource=self.__class__.plural, resource_id=self.id)
        metafield.save()
        return metafield


class Events(object):

    def events(self):
        return shopify.resources.Event.find(resource=self.__class__.plural, resource_id=self.id)
