from __future__ import unicode_literals
from __future__ import absolute_import
from django.views.generic.base import TemplateResponseMixin

from wiki.core.plugins import registry
from wiki.conf import settings


class ArticleMixin(TemplateResponseMixin):

    """A mixin that receives an article object as a parameter (usually from a wiki
    decorator) and puts this information as an instance attribute and in the
    template context."""

    def dispatch(self, request, article, *args, **kwargs):
        self.urlpath = kwargs.pop('urlpath', None)
        self.article = article
        self.children_slice = []
        if settings.SHOW_MAX_CHILDREN > 0:
            try:
                for child in self.article.get_children(
                        max_num=settings.SHOW_MAX_CHILDREN +
                        1,
                        articles__article__current_revision__deleted=False,
                        user_can_read=request.user):
                    self.children_slice.append(child)
            except AttributeError as e:
                raise Exception(
                    "Attribute error most likely caused by wrong MPTT version. Use 0.5.3+.\n\n" +
                    str(e))
        return super(ArticleMixin, self).dispatch(request, *args, **kwargs)

    def get_context_data(self, **kwargs):
        kwargs['urlpath'] = self.urlpath
        kwargs['article'] = self.article
        kwargs['article_tabs'] = registry.get_article_tabs()
        kwargs['children_slice'] = self.children_slice[:20]
        kwargs['children_slice_more'] = len(self.children_slice) > 20
        kwargs['plugins'] = registry.get_plugins()

        return kwargs
