Features: 1) Add LimitsType GraphQL object and payments_limits query to expose deposit limits; 2) Introduce LimitsSerializer and LimitsAPIView for retrieving minimal and maximal deposit amounts; 3) Implement get_limits utility to calculate deposit boundaries dynamically;

Fixes: 1) Add missing `LimitsSerializer` import in `drf.views` module;

Extra: 1) Update `.gitignore` to exclude `queries`; 2) Refactor schema and views to integrate new limits functionality.

.gitignore

@@ -167,4 +167,5 @@ cypress/screenshots/
 test.ipynb
 
 # Production stuff
-.initialized
+.initialized
+queries

engine/core/graphene/schema.py

@@ -83,6 +83,8 @@ from engine.core.utils import get_project_parameters
 from engine.core.utils.languages import get_flag_by_language
 from engine.core.utils.messages import permission_denied_message
 from engine.payments.graphene.mutations import Deposit
+from engine.payments.graphene.object_types import LimitsType
+from engine.payments.utils.gateways import get_limits
 from engine.vibes_auth.filters import UserFilter
 from engine.vibes_auth.graphene.mutations import (
     ActivateUser,
@@ -105,6 +107,7 @@ logger = logging.getLogger(__name__)
 class Query(ObjectType):
     parameters = Field(ConfigType)
     languages = List(LanguageType)
+    payments_limits = Field(LimitsType)
     products = DjangoFilterConnectionField(ProductType, filterset_class=ProductFilter)
     orders = DjangoFilterConnectionField(OrderType, filterset_class=OrderFilter)
     users = DjangoFilterConnectionField(UserType, filterset_class=UserFilter)
@@ -140,6 +143,11 @@ class Query(ObjectType):
 
         return languages
 
+    @staticmethod
+    def resolve_payments_limits(_parent, _info):
+        min_amount, max_amount = get_limits()
+        return {"min_amount": min_amount, "max_amount": max_amount}
+
     @staticmethod
     def resolve_products(_parent, info, **kwargs):
         if info.context.user.is_authenticated and kwargs.get("uuid"):

engine/payments/docs/drf/views.py

@@ -3,7 +3,7 @@ from drf_spectacular.utils import extend_schema
 from rest_framework import status
 
 from engine.core.docs.drf import error
-from engine.payments.serializers import DepositSerializer, TransactionProcessSerializer
+from engine.payments.serializers import DepositSerializer, TransactionProcessSerializer, LimitsSerializer
 
 DEPOSIT_SCHEMA = {
     "post": extend_schema(
@@ -20,3 +20,17 @@ DEPOSIT_SCHEMA = {
         },
     ),
 }
+
+LIMITS_SCHEMA = {
+    "get": extend_schema(
+        tags=[
+            "payments",
+        ],
+        summary=_("payment limits"),
+        description=_("retrieve minimal and maximal allowed deposit amounts across available gateways"),
+        responses={
+            status.HTTP_200_OK: LimitsSerializer,
+            status.HTTP_401_UNAUTHORIZED: error,
+        },
+    ),
+}

engine/payments/graphene/object_types.py

@@ -7,6 +7,11 @@ from graphene_django import DjangoObjectType
 from engine.payments.models import Balance, Transaction
 
 
+class LimitsType(graphene.ObjectType):
+    min_amount = graphene.Float()
+    max_amount = graphene.Float()
+
+
 class TransactionType(DjangoObjectType):
     process = GenericScalar()
 

engine/payments/serializers.py

@@ -29,3 +29,8 @@ class TransactionProcessSerializer(ModelSerializer):  # type: ignore [type-arg]
         model = Transaction
         fields = ("process", "order_hr_id", "order_uuid")
         read_only_fields = ("process", "order_hr_id", "order_uuid")
+
+
+class LimitsSerializer(Serializer):  # type: ignore [type-arg]
+    min_amount = FloatField(read_only=True)
+    max_amount = FloatField(read_only=True)

engine/payments/urls.py

@@ -1,7 +1,7 @@
 from django.urls import include, path
 from rest_framework.routers import DefaultRouter
 
-from engine.payments.views import CallbackAPIView, DepositView
+from engine.payments.views import CallbackAPIView, DepositView, LimitsAPIView
 from engine.payments.viewsets import TransactionViewSet
 
 app_name = "payments"
@@ -12,5 +12,6 @@ payment_router.register(prefix=r"transactions", viewset=TransactionViewSet, base
 urlpatterns = [
     path(r"", include(payment_router.urls)),
     path(r"deposit/", DepositView.as_view()),
+    path(r"limits/", LimitsAPIView.as_view()),
     path(r"<str:uuid>/callback/", CallbackAPIView.as_view()),
 ]

engine/payments/utils/gateways.py

@@ -14,3 +14,18 @@ def get_gateways_integrations(name: str | None = None) -> list[Type[AbstractGate
             class_name = gateway.integration_path.split(".")[-1]
             gateways_integrations.append(create_object(module_name, class_name))
     return gateways_integrations
+
+
+def get_limits() -> tuple[float, float]:
+    from django.db.models import Min, Max
+
+    qs = Gateway.objects.can_be_used().filter(can_be_used=True)
+
+    if not qs.exists():
+        return 0.0, 0.0
+
+    agg = qs.aggregate(min_limit=Min("minimum_transaction_amount"), max_limit=Max("maximum_transaction_amount"))
+
+    min_limit = float(agg.get("min_limit") or 0.0)
+    max_limit = float(agg.get("max_limit") or 0.0)
+    return min_limit, max_limit

engine/payments/views.py

@@ -9,10 +9,11 @@ from rest_framework.request import Request
 from rest_framework.response import Response
 from rest_framework.views import APIView
 
-from engine.payments.docs.drf.views import DEPOSIT_SCHEMA
+from engine.payments.docs.drf.views import DEPOSIT_SCHEMA, LIMITS_SCHEMA
 from engine.payments.gateways import UnknownGatewayError
 from engine.payments.models import Transaction
-from engine.payments.serializers import DepositSerializer, TransactionProcessSerializer
+from engine.payments.serializers import DepositSerializer, TransactionProcessSerializer, LimitsSerializer
+from engine.payments.utils.gateways import get_limits
 
 logger = logging.getLogger(__name__)
 
@@ -67,3 +68,15 @@ class CallbackAPIView(APIView):
             return Response(
                 status=status.HTTP_500_INTERNAL_SERVER_ERROR, data={"error": str(e), "detail": traceback.format_exc()}
             )
+
+
+@extend_schema_view(**LIMITS_SCHEMA)
+class LimitsAPIView(APIView):
+    __doc__ = _(  # type: ignore [assignment]
+        "This endpoint returns minimal and maximal allowed deposit amounts across available gateways."
+    )
+
+    def get(self, request: Request, *args: list[Any], **kwargs: dict[Any, Any]) -> Response:
+        min_amount, max_amount = get_limits()
+        data = {"min_amount": min_amount, "max_amount": max_amount}
+        return Response(LimitsSerializer(data).data, status=status.HTTP_200_OK)