Create change log entry on status updates

dav_events/models/event.py

@@ -306,11 +306,13 @@ class Event(models.Model):
             signals.event_created.send(sender=self.__class__, event=self)
             self.workflow.update_status('draft', self.editor)
         else:
-            change = EventChange(event=self, user=self.editor, operation='update', content=self.diff(original))
+            change = EventChange(event=self, user=self.editor, operation=EventChange.UPDATE,
+                                 content=self.diff(original))
             change.save()
             if not implicit_update:
                 logger.info('Event updated: %s', self)
-                signals.event_updated.send(sender=self.__class__, event=self, diff=self.diff(original, fmt='human_readable'), user=self.editor)
+                signals.event_updated.send(sender=self.__class__, event=self, user=self.editor,
+                                           diff=self.diff(original, fmt='human_readable'))
 
     def diff(self, event, fmt='json'):
         if fmt == 'human_readable':
@@ -326,16 +328,14 @@ class Event(models.Model):
             for field in fields:
                 field_name = field.name
                 from_value = getattr(event, field_name)
-                if (isinstance(from_value, datetime.datetime) or
-                   isinstance(from_value, datetime.date) or
-                   isinstance(from_value, datetime.time) or
-                   isinstance(from_value, Country)):
+                try:
+                    json.dumps(from_value)
+                except TypeError:
                     from_value = str(from_value)
                 to_value = getattr(self, field_name)
-                if (isinstance(to_value, datetime.datetime) or
-                   isinstance(to_value, datetime.date) or
-                   isinstance(to_value, datetime.time) or
-                   isinstance(to_value, Country)):
+                try:
+                    json.dumps(to_value)
+                except TypeError:
                     to_value = str(to_value)
                 if from_value != to_value:
                     change = {

dav_events/models/eventchange.py

@@ -7,10 +7,6 @@ from django.utils.encoding import python_2_unicode_compatible
 
 from . import get_ghost_user, get_system_user
 
-CHANGE_OPERATIONS = (
-    ('update', 'update'),
-)
-
 
 def get_system_user_id():
     return get_system_user().id
@@ -18,6 +14,15 @@ def get_system_user_id():
 
 @python_2_unicode_compatible
 class EventChange(models.Model):
+    UPDATE = 'update'
+    RAISE_FLAG = 'set_flag'
+    LOWER_FLAG = 'unset_flag'
+    OPERATION_CHOICES = (
+        (UPDATE, 'Update'),
+        (RAISE_FLAG, 'Raise Flag'),
+        (LOWER_FLAG, 'Lower Flag'),
+    )
+
     event = models.ForeignKey('dav_events.Event', related_name='changes')
     timestamp = models.DateTimeField(default=timezone.now)
     user = models.ForeignKey(settings.AUTH_USER_MODEL,
@@ -25,7 +30,7 @@ class EventChange(models.Model):
                              on_delete=models.SET(get_ghost_user),
                              related_name='+')
 
-    operation = models.CharField(max_length=20, choices=CHANGE_OPERATIONS)
+    operation = models.CharField(max_length=20, choices=OPERATION_CHOICES)
     content = models.TextField()
 
     class Meta: