mygpo/web/heatmap.py

   1 #
   2 # This file is part of my.gpodder.org.
   3 #
   4 # my.gpodder.org is free software: you can redistribute it and/or modify it
   5 # under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or (at your
   7 # option) any later version.
   8 #
   9 # my.gpodder.org is distributed in the hope that it will be useful, but
  10 # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  11 # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
  12 # License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with my.gpodder.org. If not, see <http://www.gnu.org/licenses/>.
  16 #
  17
  18 from mygpo.users.models import EpisodeUserState
  19
  20
  21 class EpisodeHeatmap(object):
  22     """ Information about how often certain parts of Episodes are played """
  23
  24     def __init__(self, podcast_id, episode_id=None, user_oldid=None):
  25         """ Initialize a new Episode heatmap
  26
  27         EpisodeHeatmap(podcast_id, [episode_id, [user_oldid]]) """
  28
  29         self.podcast_id = podcast_id
  30
  31         if episode_id is not None and podcast_id is None:
  32             raise ValueError('episode_id can only be used '
  33                     'if podcast_id is not None')
  34
  35         self.episode_id = episode_id
  36
  37         if user_oldid is not None and episode_id is None:
  38             raise ValueError('user_oldid can only be used '
  39                     'if episode_id is not None')
  40
  41         self.user_oldid = user_oldid
  42         self.heatmap = None
  43         self.borders = None
  44
  45
  46     def _query(self):
  47         """ Queries the database and stores the heatmap and its borders """
  48
  49         db = EpisodeUserState.get_db()
  50
  51         group_level = len(filter(None, [self.podcast_id,
  52                     self.episode_id, self.user_oldid]))
  53
  54         r = db.view('users/episode_heatmap',
  55                 startkey    = [self.podcast_id, self.episode_id,
  56                                 self.user_oldid],
  57                 endkey      = [self.podcast_id, self.episode_id or {},
  58                                 self.user_oldid or {}],
  59                 reduce      = True,
  60                 group       = True,
  61                 group_level = group_level,
  62             )
  63
  64         if not r:
  65             self.heatmap = []
  66             self.borders = []
  67         else:
  68             res = r.first()['value']
  69             self.heatmap = res['heatmap']
  70             self.borders = res['borders']
  71
  72
  73     def query_if_required():
  74         """ If required, queries the database before calling the function """
  75
  76         def decorator(f):
  77             def tmp(self, *args, **kwargs):
  78                 if None in (self.heatmap, self.borders):
  79                     self._query()
  80
  81                 return f(self, *args, **kwargs)
  82             return tmp
  83         return decorator
  84
  85
  86     @property
  87     @query_if_required()
  88     def max_plays(self):
  89         """ Returns the highest number of plays of all sections """
  90
  91         return max(self.heatmap)
  92
  93
  94     @property
  95     @query_if_required()
  96     def sections(self):
  97         """ Returns an iterator that emits (from, to, play-counts) tuples
  98
  99         Each tuple represents one part in the heatmap with a distinct
 100         play-count. from and to indicate the range of section in seconds."""
 101
 102         for i in range(len(self.heatmap)):
 103             yield (self.borders[i], self.borders[i+1], self.heatmap[i])
 104
 105
 106     @query_if_required()
 107     def __nonzero__(self):
 108         return any(self.heatmap)