fix error in gitignore

apps/payments/gateways.py

@@ -0,0 +1,36 @@
+"""Payment gateway abstraction with idempotent callbacks.
+
+Payments never talk to a concrete gateway directly; the gateway is selected
+from configuration and isolated behind an interface.
+"""
+from typing import Protocol
+
+from django.conf import settings
+
+
+class PaymentGatewayInterface(Protocol):
+    def request_payment(self, amount, currency, order_number: str, callback_url: str) -> dict:
+        """Return {'authority': str, 'redirect_url': str}."""
+        ...
+
+    def verify(self, authority: str, amount) -> dict:
+        """Return {'transaction_id': str, 'status': 'success'|'failed'|'cancelled'}."""
+        ...
+
+
+class MockGateway:
+    def request_payment(self, amount, currency, order_number: str, callback_url: str) -> dict:
+        return {
+            "authority": f"MOCK-AUTH-{order_number}",
+            "redirect_url": f"{callback_url}?authority=MOCK-AUTH-{order_number}",
+        }
+
+    def verify(self, authority: str, amount) -> dict:
+        return {"transaction_id": f"MOCK-TXN-{authority}", "status": "success"}
+
+
+def get_gateway() -> PaymentGatewayInterface:
+    if settings.PAYMENT_GATEWAY_PROVIDER == "mock":
+        return MockGateway()
+    # Real gateways (GatewayA, GatewayB, ...) are selected here.
+    return MockGateway()