refactor catalogue to separate app,

[redakcja.git] / apps / catalogue / helpers.py

diff --git a/apps/catalogue/helpers.py b/apps/catalogue/helpers.py
new file mode 100644 (file)
index 0000000..c9dc0bd
--- /dev/null
+++ b/apps/catalogue/helpers.py
@@ -0,0 +1,65 @@
+from functools import wraps
+
+from django.db.models import Count
+
+
+def active_tab(tab):
+    """
+        View decorator, which puts tab info on a request.
+    """
+    def wrapper(f):
+        @wraps(f)
+        def wrapped(request, *args, **kwargs):
+            request.catalogue_active_tab = tab
+            return f(request, *args, **kwargs)
+        return wrapped
+    return wrapper
+
+
+class ChunksList(object):
+    def __init__(self, chunk_qs):
+        self.chunk_qs = chunk_qs.annotate(
+            book_length=Count('book__chunk')).select_related(
+            'book', 'stage__name',
+            'user')
+
+        self.book_qs = chunk_qs.values('book_id')
+
+    def __getitem__(self, key):
+        if isinstance(key, slice):
+            return self.get_slice(key)
+        elif isinstance(key, int):
+            return self.get_slice(slice(key, key+1))[0]
+        else:
+            raise TypeError('Unsupported list index. Must be a slice or an int.')
+
+    def __len__(self):
+        return self.book_qs.count()
+
+    def get_slice(self, slice_):
+        book_ids = [x['book_id'] for x in self.book_qs[slice_]]
+        chunk_qs = self.chunk_qs.filter(book__in=book_ids)
+
+        chunks_list = []
+        book = None
+        for chunk in chunk_qs:
+            if chunk.book != book:
+                book = chunk.book
+                chunks_list.append(ChoiceChunks(book, [chunk], chunk.book_length))
+            else:
+                chunks_list[-1].chunks.append(chunk)
+        return chunks_list
+
+
+class ChoiceChunks(object):
+    """
+        Associates the given chunks iterable for a book.
+    """
+
+    chunks = None
+
+    def __init__(self, book, chunks, book_length):
+        self.book = book
+        self.chunks = chunks
+        self.book_length = book_length
+