from django import template
from django.core.exceptions import ObjectDoesNotExist
from django.contrib.contenttypes.models import ContentType
register = template.Library()

def show_rating(app, obj_id):
		app = token.contents.split('.')
		if app.length != 2:
			raise template.TemplateSyntaxError, "rating tag has invalid content-type '%s'" % app
		content_type = ContentType.objects.get(app_label__exact=app[0], model__exact=app[1])
		except ContentType.DoesNotExist:
			raise template.TemplateSyntaxError, "rating tag has invalid content-type '%s'" % app

		try: # ensure the object ID is valid
			content_type.get_object_for_this_type(pk=obj_id)
		except ObjectDoesNotExist:
			raise template.TemplateSyntaxError, "rating tag refers to %s object with ID %s, which doesn't exist" % (content_type.name, obj_id)
		
		context.push()
		context['target'] = '%s:%s' % (self.content_type.id, self.obj_id)
		options = []
		for var, abbr in (('rating_choices', RATING_CHOICES),):
			context[var] = getattr(self, var)
			if getattr(self, var):
				options.append(abbr)
		context['options'] = ','.join(options)
		return context

register.inclusion_tag('ratings/display.html')(show_rating)