class DynamicPreferencesException(Exception):
    detail_default = "An exception occurred with django-dynamic-preferences"

    def __init__(self, detail=None):
        if detail is not None:
            self.detail = str(detail)
        else:
            self.detail = str(self.detail_default)

    def __str__(self):
        return self.detail


class MissingDefault(DynamicPreferencesException):
    detail_default = "You must provide a default value for all preferences"


class NotFoundInRegistry(DynamicPreferencesException, KeyError):
    detail_default = "Preference with this name/section not found in registry"


class DoesNotExist(DynamicPreferencesException):
    detail_default = "Cannot retrieve preference value, ensure the preference is correctly registered and database is synced"


class CachedValueNotFound(DynamicPreferencesException):
    detail_default = "Cached value not found"


class MissingModel(DynamicPreferencesException):
    detail_default = 'You must define a model choice through "model" \
                      or "queryset" attribute'