refactor(serializers): Introduce base classes to reduce duplication

Refactor user, promo, and comment serializers to improve maintainability and reduce redundant code by using base classes.

 - Introduce `BaseUserSerializer` to share common user fields and logic between `SignUpSerializer` and `UserProfileSerializer`.
 - Create `BaseUserPromoSerializer` to consolidate common fields and methods for `PromoFeedSerializer` and `UserPromoDetailSerializer`.
- Implement `BaseCommentSerializer` to streamline `CommentSerializer`, `CommentCreateSerializer`, and `CommentUpdateSerializer`.
- Simplify the update logic in `UserProfileSerializer` and extract cache invalidation into a private `_invalidate_cache` method.

Author: RandomProgramm3r

promo_code/business/managers.py

@@ -23,31 +23,31 @@ def create_company(self, email, name, password=None, **extra_fields):
 
 class PromoManager(django.db.models.Manager):
     with_related_fields = (
-            'id',
-            'company__id',
-            'company__name',
-            'description',
-            'image_url',
-            'target',
-            'max_count',
-            'active_from',
-            'active_until',
-            'mode',
-            'promo_common',
-            'created_at',
+        'id',
+        'company__id',
+        'company__name',
+        'description',
+        'image_url',
+        'target',
+        'max_count',
+        'active_from',
+        'active_until',
+        'mode',
+        'promo_common',
+        'created_at',
     )
 
     def get_queryset(self):
         return super().get_queryset()
 
     def with_related(self):
         return (
-        self.select_related('company')
-        .prefetch_related('unique_codes')
-        .only(
-            *self.with_related_fields,
+            self.select_related('company')
+            .prefetch_related('unique_codes')
+            .only(
+                *self.with_related_fields,
+            )
         )
-    )
 
     def for_company(self, user):
         return self.with_related().filter(company=user)

promo_code/core/serializers.py

@@ -112,7 +112,8 @@ class BasePromoSerializer(rest_framework.serializers.ModelSerializer):
         required=True,
     )
     target = TargetSerializer(
-        required=True, allow_null=True,
+        required=True,
+        allow_null=True,
     )
     promo_common = rest_framework.serializers.CharField(
         min_length=business.constants.PROMO_COMMON_CODE_MIN_LENGTH,