issue #1: synchronise programs' schedules and later diffusions (update, delete); fix signal import in apps

aircox/signals.py

@@ -0,0 +1,63 @@
+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
+
+import aircox.models as models
+import aircox.utils as utils
+
+# FIXME: avoid copy of the code in schedule_post_saved and
+#        schedule_pre_delete
+
+@receiver(post_save, sender=models.Schedule)
+def schedule_post_saved(sender, instance, created, *args, **kwargs):
+    if not instance.program.sync:
+        return
+
+    initial = instance._Schedule__initial
+    if not initial or not instance.changed(['date','duration', 'frequency']):
+        return
+
+    # old schedule and timedelta
+    old_sched = models.Schedule(
+        date = initial['date'],
+        duration = initial['duration'],
+        frequency = initial['frequency'],
+    )
+    delta = instance.date - old_sched.date
+
+    # update diffusions...
+    qs = models.Diffusion.objects.get_after().filter(
+        program = instance.program
+    )
+    for diff in qs:
+        if not old_sched.match(diff.date):
+            continue
+        diff.start += delta
+        diff.end = diff.start + utils.to_timedelta(instance.duration)
+        diff.save()
+
+@receiver(pre_delete, sender=models.Schedule)
+def schedule_pre_delete(sender, instance, *args, **kwargs):
+    if not instance.program.sync:
+        return
+
+    initial = instance._Schedule__initial
+    if not initial or not instance.changed(['date','duration', 'frequency']):
+        return
+
+    old_sched = models.Schedule(
+        date = initial['date'],
+        duration = initial['duration'],
+        frequency = initial['frequency'],
+    )
+
+    qs = models.Diffusion.objects.get_after().filter(
+        program = instance.program
+    )
+    for diff in qs:
+        if not old_sched.match(diff.date):
+            continue
+        diff.delete()
+