Features: 1) Add get_integration_class_object method to Transaction for dynamic gateway class instantiation;

Fixes: 1) Validate gateway presence in `process_transaction_changes` signal; 2) Add missing imports for `Type`, `create_object`, and `AbstractGateway`;

Extra: 1) Cleanup unused diff lines in migrations files; 2) Improve JSONField, FloatField, and PositiveIntegerField declarations by consolidating into single lines; 3) Remove redundant match-case logic in `signals.py`.

blog/migrations/0007_post_is_static_page.py

@@ -4,7 +4,6 @@ from django.db import migrations, models
 
 
 class Migration(migrations.Migration):
-
     dependencies = [
         ("blog", "0006_post_meta_description_post_meta_description_ar_ar_and_more"),
     ]

core/migrations/0048_vendor_integration_path_alter_productimage_priority.py

@@ -4,7 +4,6 @@ from django.db import migrations, models
 
 
 class Migration(migrations.Migration):
-
     dependencies = [
         ("core", "0047_alter_attribute_unique_together"),
     ]

payments/migrations/0005_gateway_transaction_gateway.py

@@ -7,7 +7,6 @@ from django.db import migrations, models
 
 
 class Migration(migrations.Migration):
-
     dependencies = [
         ("payments", "0004_alter_transaction_payment_method"),
     ]
@@ -98,15 +97,11 @@ class Migration(migrations.Migration):
                 ),
                 (
                     "minimum_transaction_amount",
-                    models.FloatField(
+                    models.FloatField(default=0, verbose_name="minimum transaction amount"),
-                        default=0, verbose_name="minimum transaction amount"
-                    ),
                 ),
                 (
                     "maximum_transaction_amount",
-                    models.FloatField(
+                    models.FloatField(default=0, verbose_name="maximum transaction amount"),
-                        default=0, verbose_name="maximum transaction amount"
-                    ),
                 ),
                 (
                     "daily_limit",
@@ -126,15 +121,11 @@ class Migration(migrations.Migration):
                 ),
                 (
                     "priority",
-                    models.PositiveIntegerField(
+                    models.PositiveIntegerField(default=10, unique=True, verbose_name="priority"),
-                        default=10, unique=True, verbose_name="priority"
-                    ),
                 ),
                 (
                     "integration_variables",
-                    models.JSONField(
+                    models.JSONField(default=dict, verbose_name="integration variables"),
-                        default=dict, verbose_name="integration variables"
-                    ),
                 ),
             ],
             options={

payments/models.py

@@ -1,3 +1,5 @@
+from typing import Type
+
 from constance import config
 from django.conf import settings
 from django.contrib.postgres.indexes import GinIndex
@@ -16,6 +18,8 @@ from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _
 
 from core.abstract import NiceModel
+from evibes.utils.misc import create_object
+from payments.gateways import AbstractGateway
 
 
 class Transaction(NiceModel):
@@ -147,3 +151,14 @@ class Gateway(NiceModel):
         monthly_ok = self.monthly_limit == 0 or monthly_sum < self.monthly_limit
 
         return daily_ok and monthly_ok
+
+    def get_integration_class_object(self, raise_exc: bool = True) -> Type[AbstractGateway] | None:
+        if not self.integration_path:
+            if raise_exc:
+                raise ValueError(_("gateway integration path is not set"))
+            return None
+        try:
+            module_name, class_name = self.integration_path.rsplit(".", 1)
+        except ValueError as exc:
+            raise ValueError(_("invalid integration path: %(path)s") % {"path": self.integration_path}) from exc
+        return create_object(module_name, class_name)

payments/signals.py

@@ -24,15 +24,10 @@ def create_balance_on_user_creation_signal(instance: User, created: bool, **kwar
 @receiver(post_save, sender=Transaction)
 def process_transaction_changes(instance: Transaction, created: bool, **kwargs: dict[Any, Any]) -> None:
     if created:
+        if not instance.gateway:
+            raise ValueError("gateway is required to process a transaction")
         try:
-            gateway = None
+            gateway = instance.gateway.get_integration_class_object()
-            match instance.process.get("gateway", "default"):
-                case "gateway":
-                    gateway = AbstractGateway()
-                case "default":
-                    gateway = AbstractGateway()
-                case _:
-                    gateway = AbstractGateway()
             gateway.process_transaction(instance)
         except Exception as e:
             instance.process = {"status": "ERRORED", "error": str(e)}