Merge pull request #45 from udacity/sort_modes

Pagination updates

diff --combined forum/views/readers.py
index a8b94e92e200bec718b5f77aec4a07a4b2d1cb1f,e7336e01fe9b45b43ef21e1c913bd730e6e11581..fc819bf164b77f5ed5a2ff36c78d57f8f3956223
--- 1/forum/views/readers.py
--- 2/forum/views/readers.py
+++ b/forum/views/readers.py
@@@ -8,7 -8,6 +8,7 @@@ from django.core.paginator import Pagin
  from django.template import RequestContext
  from django import template
  from django.utils.html import *
 +from django.utils.http import urlquote
  from django.db.models import Q, Count
  from django.utils.translation import ugettext as _
  from django.core.urlresolvers import reverse
@@@ -30,9 -29,28 +30,28 @@@ import decorator
  
  class HottestQuestionsSort(pagination.SortBase):
      def apply(self, questions):
-         return questions.annotate(new_child_count=Count('all_children')).filter(
-                 all_children__added_at__gt=datetime.datetime.now() - datetime.timedelta(days=1)).order_by('-new_child_count')
+         return questions.extra(select={'new_child_count': '''
+             SELECT COUNT(1)
+                 FROM forum_node fn1
+                 WHERE fn1.abs_parent_id = forum_node.id
+                     AND fn1.id != forum_node.id
+                     AND NOT(fn1.state_string LIKE '%%(deleted)%%')
+                     AND added_at > %s'''
+             },
+             select_params=[ (datetime.datetime.now() - datetime.timedelta(days=2))
+                 .strftime('%Y-%m-%d')]
+         ).order_by('-new_child_count', 'last_activity_at')
  
+ class UnansweredQuestionsSort(pagination.SortBase):
+     def apply(self, questions):
+         return questions.extra(select={'answer_count': '''
+             SELECT COUNT(1)
+                 FROM forum_node fn1
+                 WHERE fn1.abs_parent_id = forum_node.id
+                     AND fn1.id != forum_node.id
+                     AND fn1.node_type='answer'
+                     AND NOT(fn1.state_string LIKE '%%(deleted)%%')'''
+             }).order_by('answer_count', 'last_activity_at')
  
  class QuestionListPaginatorContext(pagination.PaginatorContext):
      def __init__(self, id='QUESTIONS_LIST', prefix='', pagesizes=(15, 30, 50), default_pagesize=30):
@@@ -41,6 -59,7 +60,7 @@@
              (_('newest'), pagination.SimpleSort(_('newest'), '-added_at', _("most <strong>recently asked</strong> questions"))),
              (_('hottest'), HottestQuestionsSort(_('hottest'), _("most <strong>active</strong> questions in the last 24 hours</strong>"))),
              (_('mostvoted'), pagination.SimpleSort(_('most voted'), '-score', _("most <strong>voted</strong> questions"))),
+             (_('unanswered'), UnansweredQuestionsSort('unanswered', "questions with no answers")),
          ), pagesizes=pagesizes, default_pagesize=default_pagesize, prefix=prefix)
  
  class AnswerSort(pagination.SimpleSort):
@@@ -53,6 -72,7 +73,7 @@@
  class AnswerPaginatorContext(pagination.PaginatorContext):
      def __init__(self, id='ANSWER_LIST', prefix='', default_pagesize=10):
          super (AnswerPaginatorContext, self).__init__(id, sort_methods=(
+             (_('active'), AnswerSort(_('active answers'), '-last_activity_at', _("most recently updated answers/comments will be shown first"))),
              (_('oldest'), AnswerSort(_('oldest answers'), 'added_at', _("oldest answers will be shown first"))),
              (_('newest'), AnswerSort(_('newest answers'), '-added_at', _("newest answers will be shown first"))),
              (_('votes'), AnswerSort(_('popular answers'), ('-score', 'added_at'), _("most voted answers will be shown first"))),