track m2m changes

src/c3nav/editor/models.py

@@ -98,17 +98,26 @@ class ChangeSet(models.Model):
         for name, value in kwargs.items():
             setattr(change, name, value)
         change.save()
-        print(repr(change))
+        # print(repr(change))
         return change
 
     def add_create(self, obj, author=None):
         change = self._new_change(author=author, action='create', model_class=type(obj._obj))
         obj.pk = 'c%d' % change.pk
 
-    def add_update(self, obj, name, value, author=None):
-        return self._new_change(author=author, action='update', obj=obj,
+    def _add_value(self, action, obj, name, value, author=None):
+        return self._new_change(author=author, action=action, obj=obj,
                                 field_name=name, field_value=json.dumps(value, ensure_ascii=False))
 
+    def add_update(self, obj, name, value, author=None):
+        return self._add_value('update', obj, name, value, author)
+
+    def add_m2m_add(self, obj, name, value, author=None):
+        return self._add_value('m2m_add', obj, name, value, author)
+
+    def add_m2m_remove(self, obj, name, value, author=None):
+        return self._add_value('m2m_remove', obj, name, value, author)
+
     def add_delete(self, obj, author=None):
         return self._new_change(author=author, action='delete', obj=obj)
 
@@ -183,8 +192,11 @@ class Change(models.Model):
         raise TypeError('existing_model_pk or created_object have to be set.')
 
     @obj.setter
-    def obj(self, value: models.Model):
-        if isinstance(value, ModelInstanceWrapper) and isinstance(value.pk, str):
+    def obj(self, value):
+        if not isinstance(value, ModelInstanceWrapper):
+            value = self.changeset.wrap(value)
+
+        if isinstance(value.pk, str):
             if value._changeset.id != self.changeset.pk:
                 raise ValueError('value is a Change instance but belongs to a different changeset.')
             self.model_class = type(value._obj)
@@ -252,5 +264,9 @@ class Change(models.Model):
             result += 'Update object '+repr(self.obj)+': '+self.field_name+'='+self.field_value
         elif self.action == 'delete':
             result += 'Delete object '+repr(self.obj)
+        elif self.action == 'm2m_add':
+            result += 'Update (m2m) object '+repr(self.obj)+': '+self.field_name+'.add('+self.field_value+')'
+        elif self.action == 'm2m_remove':
+            result += 'Update (m2m) object '+repr(self.obj)+': '+self.field_name+'.remove('+self.field_value+')'
         result += '>'
         return result

src/c3nav/editor/views.py

@@ -226,7 +226,7 @@ def edit(request, pk=None, model=None, level=None, space=None, on_top_of=None, e
                 obj.on_top_of = on_top_of
 
             obj.save()
-            # form.save_m2m()
+            form.save_m2m()
             # request.changeset.changes.all().delete()
 
             return redirect(ctx['back_url'])

src/c3nav/editor/wrappers.py

@@ -19,6 +19,8 @@ class BaseWrapper:
         return ModelInstanceWrapper(self._changeset, instance, self._author)
 
     def _wrap_manager(self, manager):
+        if hasattr(manager, 'through'):
+            return ManyRelatedManagerWrapper(self._changeset, manager, self._author)
         return ManagerWrapper(self._changeset, manager, self._author)
 
     def _wrap_queryset(self, queryset):
@@ -37,8 +39,6 @@ class BaseWrapper:
         elif callable(value) and name not in self._allowed_callables:
             if not isinstance(self, ModelInstanceWrapper) or hasattr(models.Model, name):
                 raise TypeError('Can not call %s.%s wrapped!' % (self._obj, name))
-
-        # print(self._obj, name, type(value), value)
         return value
 
     def __setattr__(self, name, value):
@@ -212,5 +212,37 @@ class ManagerWrapper(BaseQueryWrapper):
     pass
 
 
+class ManyRelatedManagerWrapper(ManagerWrapper):
+    def _check_through(self):
+        if not self._obj.through._meta.auto_created:
+            raise AttributeError('Cannot do this an a ManyToManyField which specifies an intermediary model.')
+
+    def set(self, objs, author=None):
+        if author is None:
+            author = self._author
+
+        old_ids = set(self.values_list('pk', flat=True))
+        new_ids = set(obj.pk for obj in objs)
+
+        self.remove(*(old_ids - new_ids))
+        self.add(*(new_ids - old_ids))
+
+    def add(self, *objs, author=None):
+        if author is None:
+            author = self._author
+
+        for obj in objs:
+            pk = (obj.pk if isinstance(obj, self._obj.model) else obj)
+            self._changeset.add_m2m_add(self._obj.instance, name=self.prefetch_cache_name, value=pk, author=author)
+
+    def remove(self, *objs, author=None):
+        if author is None:
+            author = self._author
+
+        for obj in objs:
+            pk = (obj.pk if isinstance(obj, self._obj.model) else obj)
+            self._changeset.add_m2m_remove(self._obj.instance, name=self.prefetch_cache_name, value=pk, author=author)
+
+
 class QuerySetWrapper(BaseQueryWrapper):
     pass