issue #1: synchronise diffusions + delete empty diffusion and programs page when related object are deleted

aircox_cms/models.py

@@ -384,6 +384,7 @@ class ProgramPage(Publication):
         verbose_name = _('program'),
         related_name = 'page',
         on_delete=models.SET_NULL,
+        unique = True,
         blank=True, null=True,
     )
     # rss = models.URLField()
@@ -469,8 +470,11 @@ class DiffusionPage(Publication):
         aircox.models.Diffusion,
         verbose_name = _('diffusion'),
         related_name = 'page',
-        on_delete=models.SET_NULL,
+        unique = True,
         null=True,
+        # not blank because we enforce the connection to a diffusion
+        #   (still users always tend to break sth)
+        on_delete=models.SET_NULL,
         limit_choices_to = {
             'initial__isnull': True,
         },

aircox_cms/signals.py

@@ -1,4 +1,4 @@
-from django.db.models.signals import post_save
+from django.db.models.signals import post_save, pre_delete
 from django.dispatch import receiver
 from django.utils.translation import ugettext as _, ugettext_lazy
 from django.contrib.contenttypes.models import ContentType
@@ -131,4 +131,35 @@ def program_post_saved(sender, instance, created, *args, **kwargs):
     )
     parent.add_child(instance = page)
 
+@receiver(pre_delete, sender=aircox.Program)
+def program_post_deleted(sender, instance, *args, **kwargs):
+    if not instance.page or (
+            instance.page.first().body or
+            Page.objects.descendant_of(instance).count()
+            ):
+        return
+    instance.page.delete()
+
+
+@receiver(post_save, sender=aircox.Diffusion)
+def diffusion_post_saved(sender, instance, created, *args, **kwargs):
+    import aircox_cms.models as models
+    # TODO/FIXME:   what about confirmed/unconfirmed;
+    #               what about delete when not confirmed?
+    if not created or instance.page.count():
+        return
+
+    page = models.DiffusionPage.from_diffusion(
+        instance, live = False
+    )
+    instance.program.page.first().add_child(
+        instance = page
+    )
+
+@receiver(pre_delete, sender=aircox.Program)
+def diffusion_post_deleted(sender, instance, *args, **kwargs):
+    if not instance.page or instance.page.first().body:
+        return
+    instance.page.delete()
+