mygpo/users/subscriptions.py

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