mygpo/users/subscriptions.py

   1 from mygpo.podcasts.models import Podcast
   2 from mygpo.db.couchdb.user import get_num_listened_episodes
   3
   4
   5 class PodcastSorter(object):
   6     """ Sorts a list of podcast """
   7
   8     def __init__(self, podcasts):
   9         self.podcasts = podcasts
  10         self.sorted_podcasts = None
  11
  12
  13     def _sort(self):
  14         return self.podcasts
  15
  16
  17     def __len__(self):
  18         return len(self.podcasts)
  19
  20
  21     def __getitem__(self, val):
  22         if self.sorted_podcasts is None:
  23             self.sorted_podcasts = self._sort()
  24
  25         return self.sorted_podcasts.__getitem__(val)
  26
  27     def __iter__(self):
  28         if self.sorted_podcasts is None:
  29             self.sorted_podcasts = self._sort()
  30
  31         return iter(self.sorted_podcasts)
  32
  33
  34
  35 class PodcastPercentageListenedSorter(PodcastSorter):
  36     """ Sorts podcasts by the percentage of listened episodes
  37
  38     Adds the attributes percent_listened and episodes_listened to the podcasts
  39
  40     Cost: 1 DB query """
  41
  42     def __init__(self, podcasts, user):
  43         super(PodcastPercentageListenedSorter, self).__init__(podcasts)
  44         self.user = user
  45
  46
  47     def _sort(self):
  48
  49         SORT_KEY = lambda podcast: podcast.percent_listened
  50
  51         counts = dict(get_num_listened_episodes(self.user))
  52         for podcast in self.podcasts:
  53             c = counts.get(podcast.get_id(), 0)
  54             if podcast.episode_count:
  55                 podcast.percent_listened = c / float(podcast.episode_count)
  56                 podcast.episodes_listened = c
  57             else:
  58                 podcast.percent_listened = 0
  59                 podcast.episodes_listened = 0
  60
  61         return sorted(self.podcasts, key=SORT_KEY, reverse=True)
  62
  63
  64 def subscription_changes(device_id, podcast_states, since, until):
  65     """ returns subscription changes for the device and podcast states """
  66
  67     add, rem = [], []
  68     for p_state in podcast_states:
  69         change = p_state.get_change_between(device_id, since, until)
  70         if change == 'subscribe':
  71             add.append( p_state.ref_url )
  72         elif change == 'unsubscribe':
  73             rem.append( p_state.ref_url )
  74
  75     return add, rem
  76
  77
  78 def podcasts_for_states(podcast_states):
  79     """ returns the podcasts corresponding to the podcast states """
  80
  81     podcast_ids = [state.podcast for state in podcast_states]
  82     podcasts = Podcast.objects.filter(id__in=podcast_ids)
  83     podcasts = {podcast.id.hex: podcast for podcast in podcasts}
  84     return podcasts.values()
  85
  86
  87
  88 def get_subscribed_podcasts(user, public=None):
  89     """ Returns all subscribed podcasts for the user
  90
  91     The attribute "url" contains the URL that was used when subscribing to
  92     the podcast """
  93
  94     from mygpo.db.couchdb.podcast_state import get_subscribed_podcast_states_by_user
  95     states = get_subscribed_podcast_states_by_user(user.profile.uuid.hex, public)
  96     podcast_ids = [state.podcast for state in states]
  97     podcasts = Podcast.objects.filter(id__in=podcast_ids)
  98     podcasts = {podcast.id: podcast for podcast in podcasts}
  99
 100     for state in states:
 101         podcast = podcasts.get(state.podcast, None)
 102         if podcast is None:
 103             continue
 104
 105         podcast = proxy_object(podcast, url=state.ref_url)
 106         podcasts[state.podcast] = podcast
 107
 108     return set(podcasts.values())