src/social/utils.py

   1 # This file is part of Wolne Lektury, licensed under GNU Affero GPLv3 or later.
   2 # Copyright © Fundacja Wolne Lektury. See NOTICE for more information.
   3 #
   4 from collections import defaultdict
   5 from random import randint
   6
   7 from django.contrib.contenttypes.models import ContentType
   8 from django.db.models import Q
   9 from django.utils.functional import lazy
  10 from catalogue.models import Book
  11 from social.models import Cite
  12 from social import models
  13
  14
  15 def likes(user, work, request=None):
  16     if not user.is_authenticated:
  17         return False
  18
  19     if request is None:
  20         return models.UserList.likes(user, work)
  21
  22     if not hasattr(request, 'social_likes'):
  23         # tuple: unchecked, checked, liked
  24         request.social_likes = defaultdict(lambda: (set(), set(), set()))
  25
  26     ct = ContentType.objects.get_for_model(type(work))
  27     likes_t = request.social_likes[ct.pk]
  28     if work.pk in likes_t[1]:
  29         return work.pk in likes_t[2]
  30     else:
  31         likes_t[0].add(work.pk)
  32
  33         def _likes():
  34             if likes_t[0]:
  35                 ids = tuple(likes_t[0])
  36                 likes_t[0].clear()
  37                 ls = models.UserList.get_favorites_list(user)
  38                 if ls is None:
  39                     return False
  40                 likes_t[2].update(
  41                     ls.userlistitem_set.filter(deleted=False).filter(
  42                         book_id__in=ids).values_list('book_id', flat=True))
  43                 likes_t[1].update(ids)
  44             return work.pk in likes_t[2]
  45         return lazy(_likes, bool)()
  46
  47
  48 def cites_for_tags(tags):
  49     """Returns a QuerySet with all Cites for books with given tags."""
  50     return Cite.objects.filter(book__in=Book.tagged.with_all(tags))
  51
  52
  53 # tag_ids is never used
  54 def choose_cite(book_id=None, tag_ids=None):
  55     """Choose a cite for main page, for book or for set of tags."""
  56     if book_id is not None:
  57         cites = Cite.objects.filter(Q(book=book_id) | Q(book__ancestor=book_id))
  58     elif tag_ids is not None:
  59         tags = Tag.objects.filter(pk__in=tag_ids)
  60         cites = cites_for_tags(tags)
  61     else:
  62         cites = Cite.objects.all()
  63     stickies = cites.filter(sticky=True)
  64     count = len(stickies)
  65     if count:
  66         cites = stickies
  67     else:
  68         count = len(cites)
  69     if count:
  70         cite = cites[randint(0, count - 1)]
  71     else:
  72         cite = None
  73     return cite
  74
  75
  76 def get_or_choose_cite(request, book_id=None, tag_ids=None):
  77     try:
  78         assert request.user.is_staff
  79         assert 'banner' in request.GET
  80         return Cite.objects.get(pk=request.GET['banner'])
  81     except (AssertionError, Cite.DoesNotExist):
  82         return choose_cite(book_id, tag_ids)