added objects related statistic in Collection backoffice serializer

apps/collection/models.py

@@ -87,6 +87,42 @@ class Collection(ProjectBaseMixin, CollectionDateMixin,
         verbose_name = _('collection')
         verbose_name_plural = _('collections')
 
+    @property
+    def _related_objects(self) -> list:
+        """Return list of related objects."""
+        related_objects = []
+        # get related objects
+        for related_object in self._meta.related_objects:
+            related_objects.append(related_object)
+        return related_objects
+
+    @property
+    def count_related_objects(self) -> int:
+        """Return count of related objects."""
+        counter = 0
+        # count of related objects
+        for related_object in [related_object.name for related_object in self._related_objects]:
+            counter += getattr(self, f'{related_object}').count()
+        return counter
+
+    @property
+    def related_object_names(self) -> list:
+        """Return related object names."""
+        raw_object_names = []
+        for related_object in [related_object.name for related_object in self._related_objects]:
+            instances = getattr(self, f'{related_object}')
+            if instances.exists():
+                for instance in instances.all():
+                    raw_object_names.append(instance.slug if hasattr(instance, 'slug') else None)
+
+        # parse slugs
+        object_names = []
+        re_pattern = r'[\w]+'
+        for raw_name in raw_object_names:
+            result = re.findall(re_pattern, raw_name)
+            if result: object_names.append(' '.join(result).capitalize())
+        return set(object_names)
+
 
 class GuideTypeQuerySet(models.QuerySet):
     """QuerySet for model GuideType."""

apps/collection/serializers/back.py

@@ -19,6 +19,8 @@ class CollectionBackOfficeSerializer(CollectionBaseSerializer):
     collection_type_display = serializers.CharField(
         source='get_collection_type_display', read_only=True)
     country = CountrySimpleSerializer(read_only=True)
+    count_related_objects = serializers.IntegerField(read_only=True)
+    related_object_names = serializers.ListField(read_only=True)
 
     class Meta:
         model = models.Collection
@@ -36,6 +38,8 @@ class CollectionBackOfficeSerializer(CollectionBaseSerializer):
             'slug',
             'start',
             'end',
+            'count_related_objects',
+            'related_object_names',
         ]