add DiffusionManager, use it

website/models.py

@@ -50,13 +50,60 @@ class Program (cms.RelatedPost):
         auto_create = True
 
 
-class Diffusion (cms.RelatedPost):
+class DiffusionManager(models.Manager):
+    @staticmethod
+    def post_or_default(diff, post, create = True, save = False):
+        if not post and create:
+            post = Diffusion(related = diff.initial or diff)
+            if save:
+                post.save()
+            else:
+                post.rel_to_post()
+        if post:
+            post.date = diff.start
+            post.related = diff
+        return post
+
+    def get_for(self, diffs, create = True, save = False):
+        """
+        Get posts for the given related diffusion. Return a list
+        not a Queryset, ordered following the given list.
+
+        Update the post objects to make date corresponding to the
+        diffusions.
+
+        - diffs: a programs.Diffusion, or iterable of
+            programs.Diffusion. In the first case, return
+            an object instead of a list
+        - create: create a post for each Diffusion if missing
+        - save: save the created posts
+        """
+        if not hasattr(diffs, '__iter__'):
+            qs = self.filter(related = diffs.initial or diff,
+                             published = True)
+            return post_or_default(diffs, post, create, save)
+
+        qs = self.filter(related__in = [
+            diff.initial or diff for diff in diffs
+        ], published = True)
+        posts = []
+        for diff in diffs:
+            post = qs.filter(related = diff.initial or diff).first()
+            post = self.post_or_default(diff, post, create, save)
+            if post:
+                posts.append(post)
+        return posts
+
+
+class Diffusion(cms.RelatedPost):
+    objects = DiffusionManager()
     actions = [actions.Play, actions.AddToPlaylist]
 
     class Relation:
         model = programs.Diffusion
         bindings = {
             'thread': 'program',
+            'title': lambda post, rel: rel.program.name,
             'date': 'start',
         }
         fields_args = {
@@ -69,9 +116,16 @@ class Diffusion (cms.RelatedPost):
         def auto_create(object):
             return not object.initial
 
-    def __init__(self, *args, **kwargs):
+    def __init__(self, *args, rel_to_post = False, **kwargs):
         super().__init__(*args, **kwargs)
+        if rel_to_post and self.related:
+            self.rel_to_post()
+
         self.fill_empty()
+        if not self.subtitle:
+            self.subtitle = _('Diffusion of the %(date)s') % {
+                'date': self.related.start.strftime('%A %d/%m')
+            }
 
     @property
     def info(self):
@@ -81,3 +135,14 @@ class Diffusion (cms.RelatedPost):
             'day': self.related.initial.start.strftime('%A %d/%m')
         }
 
+    def url(self):
+        url = super().url()
+        if url or not self.related.initial:
+            return url
+
+        post = Diffusions.objects.filter(related = self.related.initial) \
+                                 .first()
+        return post.url() if post else ''
+
+
+