apps/catalogue/helpers.py

   1 from functools import wraps
   2
   3 from django.db.models import Count
   4
   5
   6 def active_tab(tab):
   7     """
   8         View decorator, which puts tab info on a request.
   9     """
  10     def wrapper(f):
  11         @wraps(f)
  12         def wrapped(request, *args, **kwargs):
  13             request.catalogue_active_tab = tab
  14             return f(request, *args, **kwargs)
  15         return wrapped
  16     return wrapper
  17
  18
  19 class ChunksList(object):
  20     def __init__(self, chunk_qs):
  21         self.chunk_qs = chunk_qs.annotate(
  22             book_length=Count('book__chunk')).select_related(
  23             'book', 'stage__name',
  24             'user')
  25
  26         self.book_qs = chunk_qs.values('book_id')
  27
  28     def __getitem__(self, key):
  29         if isinstance(key, slice):
  30             return self.get_slice(key)
  31         elif isinstance(key, int):
  32             return self.get_slice(slice(key, key+1))[0]
  33         else:
  34             raise TypeError('Unsupported list index. Must be a slice or an int.')
  35
  36     def __len__(self):
  37         return self.book_qs.count()
  38
  39     def get_slice(self, slice_):
  40         book_ids = [x['book_id'] for x in self.book_qs[slice_]]
  41         chunk_qs = self.chunk_qs.filter(book__in=book_ids)
  42
  43         chunks_list = []
  44         book = None
  45         for chunk in chunk_qs:
  46             if chunk.book != book:
  47                 book = chunk.book
  48                 chunks_list.append(ChoiceChunks(book, [chunk], chunk.book_length))
  49             else:
  50                 chunks_list[-1].chunks.append(chunk)
  51         return chunks_list
  52
  53
  54 class ChoiceChunks(object):
  55     """
  56         Associates the given chunks iterable for a book.
  57     """
  58
  59     chunks = None
  60
  61     def __init__(self, book, chunks, book_length):
  62         self.book = book
  63         self.chunks = chunks
  64         self.book_length = book_length
  65