From 3fe3d571bb2bdbe206ebab1bf12547b6bde14692 Mon Sep 17 00:00:00 2001
From: Egor fureunoir Gorbunov <contact@fureunoir.com>
Date: Wed, 22 Oct 2025 11:12:30 +0300
Subject: [PATCH 1/2] Features: 1) Add `GatewayManager` and `GatewayQuerySet`
 to handle advanced gateway filtering and usage checks; 2) Integrate
 `GatewayManager` with `Gateway` model for automatic query filtering; 3)
 Introduce `can_be_used` query annotation for gateway availability.

Fixes: 1) Default to a usable `Gateway` when processing new transactions if none is specified.

Extra: 1) Add missing import for `GatewayManager` in `payments.models`; 2) Refactor gateway availability logic into the manager and query set for cleaner code organization.
---
 payments/managers.py | 44 ++++++++++++++++++++++++++++++++++++++++++++
 payments/models.py   |  5 +++++
 payments/signals.py  |  4 ++--
 3 files changed, 51 insertions(+), 2 deletions(-)
 create mode 100644 payments/managers.py

diff --git a/payments/managers.py b/payments/managers.py
new file mode 100644
index 00000000..c4684f87
--- /dev/null
+++ b/payments/managers.py
@@ -0,0 +1,44 @@
+from django.db.models import BooleanField, Case, F, Manager, Q, QuerySet, Sum, Value, When
+from django.db.models.functions import Coalesce
+from django.utils.timezone import now
+
+
+class GatewayQuerySet(QuerySet):
+    def with_usage_sums(self) -> QuerySet:
+        today = now().date()
+        current_month_start = today.replace(day=1)
+        return self.annotate(
+            daily_sum=Coalesce(Sum("transactions__amount", filter=Q(transactions__created__date=today)), Value(0.0)),
+            monthly_sum=Coalesce(
+                Sum("transactions__amount", filter=Q(transactions__created__gte=current_month_start)), Value(0.0)
+            ),
+        )
+
+    def can_be_used(self) -> QuerySet:
+        qs = self.with_usage_sums()
+        qs = qs.annotate(
+            daily_ok=Case(
+                When(daily_limit=0, then=Value(True)),
+                When(daily_sum__lt=F("daily_limit"), then=Value(True)),
+                default=Value(False),
+                output_field=BooleanField(),
+            ),
+            monthly_ok=Case(
+                When(monthly_limit=0, then=Value(True)),
+                When(monthly_sum__lt=F("monthly_limit"), then=Value(True)),
+                default=Value(False),
+                output_field=BooleanField(),
+            ),
+        )
+        return qs.annotate(
+            can_be_used=Case(
+                When(daily_ok=True, monthly_ok=True, is_active=True, then=Value(True)),
+                default=Value(False),
+                output_field=BooleanField(),
+            )
+        ).order_by("-priority")
+
+
+class GatewayManager(Manager.from_queryset(GatewayQuerySet)):
+    def get_queryset(self) -> QuerySet:
+        return super().get_queryset().can_be_used()
diff --git a/payments/models.py b/payments/models.py
index 78fc9c68..398e3525 100644
--- a/payments/models.py
+++ b/payments/models.py
@@ -20,6 +20,7 @@ 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
+from payments.managers import GatewayManager
 
 
 class Transaction(NiceModel):
@@ -87,6 +88,7 @@ class Balance(NiceModel):
 
 
 class Gateway(NiceModel):
+    objects = GatewayManager()
     name = CharField(max_length=20, null=False, blank=False, verbose_name=_("name"))
     default_currency = CharField(
         max_length=4,
@@ -138,6 +140,9 @@ class Gateway(NiceModel):
 
     @property
     def can_be_used(self) -> bool:
+        if not self.is_active:
+            return False
+
         today = now().date()
         current_month_start = today.replace(day=1)
 
diff --git a/payments/signals.py b/payments/signals.py
index 32e3dd59..d108edac 100644
--- a/payments/signals.py
+++ b/payments/signals.py
@@ -5,7 +5,7 @@ from typing import Any
 from django.db.models.signals import post_save
 from django.dispatch import receiver
 
-from payments.models import Balance, Transaction
+from payments.models import Balance, Transaction, Gateway
 from payments.utils.emailing import balance_deposit_email
 from vibes_auth.models import User
 
@@ -24,7 +24,7 @@ def create_balance_on_user_creation_signal(instance: User, created: bool, **kwar
 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")
+            instance.gateway = Gateway.objects.can_be_used().first()
         try:
             gateway = instance.gateway.get_integration_class_object()
             gateway.process_transaction(instance)

From ec8c1039f3623c2eb78af9a67a738ceeb4db0afd Mon Sep 17 00:00:00 2001
From: Egor fureunoir Gorbunov <contact@fureunoir.com>
Date: Wed, 22 Oct 2025 11:23:45 +0300
Subject: [PATCH 2/2] Features: 1) Add setter method for `can_be_used` property
 in payments model;

Fixes: None;

Extra: None;
---
 payments/models.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/payments/models.py b/payments/models.py
index 398e3525..ca0c73d5 100644
--- a/payments/models.py
+++ b/payments/models.py
@@ -157,6 +157,10 @@ class Gateway(NiceModel):
 
         return daily_ok and monthly_ok
 
+    @can_be_used.setter
+    def can_be_used(self, value: bool):
+        self.__dict__["can_be_used"] = value
+
     def get_integration_class_object(self, raise_exc: bool = True) -> Type[AbstractGateway] | None:
         if not self.integration_path:
             if raise_exc: