mygpo/users/subscriptions.py

   1 from mygpo.podcasts.models import Podcast
   2 from mygpo.core.proxy import proxy_object
   3 from mygpo.db.couchdb.user import get_num_listened_episodes
   4
   5
   6 class PodcastSorter(object):
   7     """ Sorts a list of podcast """
   8
   9     def __init__(self, podcasts):
  10         self.podcasts = podcasts
  11         self.sorted_podcasts = None
  12
  13
  14     def _sort(self):
  15         return self.podcasts
  16
  17
  18     def __len__(self):
  19         return len(self.podcasts)
  20
  21
  22     def __getitem__(self, val):
  23         if self.sorted_podcasts is None:
  24             self.sorted_podcasts = self._sort()
  25
  26         return self.sorted_podcasts.__getitem__(val)
  27
  28     def __iter__(self):
  29         if self.sorted_podcasts is None:
  30             self.sorted_podcasts = self._sort()
  31
  32         return iter(self.sorted_podcasts)
  33
  34
  35
  36 class PodcastPercentageListenedSorter(PodcastSorter):
  37     """ Sorts podcasts by the percentage of listened episodes
  38
  39     Adds the attributes percent_listened and episodes_listened to the podcasts
  40
  41     Cost: 1 DB query """
  42
  43     def __init__(self, podcasts, user):
  44         super(PodcastPercentageListenedSorter, self).__init__(podcasts)
  45         self.user = user
  46
  47
  48     def _sort(self):
  49
  50         SORT_KEY = lambda podcast: podcast.percent_listened
  51
  52         counts = dict(get_num_listened_episodes(self.user))
  53         for podcast in self.podcasts:
  54             c = counts.get(podcast.get_id(), 0)
  55             if podcast.episode_count:
  56                 podcast.percent_listened = c / float(podcast.episode_count)
  57                 podcast.episodes_listened = c
  58             else:
  59                 podcast.percent_listened = 0
  60                 podcast.episodes_listened = 0
  61
  62         return sorted(self.podcasts, key=SORT_KEY, reverse=True)
  63
  64
  65 def subscription_changes(device_id, podcast_states, since, until):
  66     """ returns subscription changes for the device and podcast states """
  67
  68     add, rem = [], []
  69     for p_state in podcast_states:
  70         change = p_state.get_change_between(device_id, since, until)
  71         if change == 'subscribe':
  72             add.append( p_state.ref_url )
  73         elif change == 'unsubscribe':
  74             rem.append( p_state.ref_url )
  75
  76     return add, rem
  77
  78
  79 def podcasts_for_states(podcast_states):
  80     """ returns the podcasts corresponding to the podcast states """
  81
  82     podcast_ids = [state.podcast for state in podcast_states]
  83     podcasts = Podcast.objects.filter(id__in=podcast_ids)
  84     podcasts = {podcast.id: podcast for podcast in podcasts}
  85
  86     for state in podcast_states:
  87         podcast = proxy_object(podcasts[state.podcast], url=state.ref_url)
  88         podcasts[state.podcast] = podcast
  89
  90     return podcasts.values()