Path ordering

Properly handle ordering in ElementPath

arkindex/documents/models.py

@@ -121,7 +121,7 @@ class Element(IndexableModel):
             raise ValueError('Cannot add a descendant as a parent')
 
         if order is None:
-            order = parent.get_next_order()
+            order = parent.get_next_order(self.type)
 
         # Create new base link
         ElementLink.objects.create(parent=parent, child=self, order=order)
@@ -173,11 +173,14 @@ class Element(IndexableModel):
         # Finally create all new paths
         ElementPath.objects.bulk_create(new_paths)
 
-    def get_next_order(self):
+    def get_next_order(self, type):
         """
         Find the next ordering for a new child in ElementPath
         """
-        return ElementPath.objects.filter(path__last=self.id).aggregate(max=models.Max('ordering') + 1)['max'] or 0
+        assert isinstance(type, ElementType)
+        return ElementPath.objects \
+                          .filter(path__last=self.id, element__type=type) \
+                          .aggregate(max=models.Max('ordering') + 1)['max'] or 0
 
     def __str__(self):
         return '{} : {}'.format(self.type, self.name)