Refactor UpdatePaymentSerializer to include only number_of_months field, add DeletePaymentView for payment deletion, and enhance VerifyPaymentView with payment_id lookup. Introduce pending_payment_id field in DeviceSerializer to track unpaid payments.

devices/serializers.py

@@ -1,6 +1,7 @@
 from rest_framework import serializers
 from .models import Device
 from api.serializers import CustomReadOnlyUserSerializer
+from billing.models import Payment  # Import the Payment model
 
 
 class CreateDeviceSerializer(serializers.ModelSerializer):
@@ -32,10 +33,21 @@ class BlockDeviceSerializer(serializers.ModelSerializer):
 
 
 class DeviceSerializer(serializers.ModelSerializer):
+    pending_payment_id = serializers.SerializerMethodField()
+
     class Meta:
         model = Device
         fields = "__all__"
 
+    def get_pending_payment_id(self, obj):
+        # Query the last unpaid payment for the device
+        unpaid_payment = (
+            Payment.objects.filter(devices=obj, paid=False)
+            .order_by("-created_at")
+            .first()
+        )
+        return unpaid_payment.id if unpaid_payment else None
+
 
 class ReadOnlyDeviceSerializer(serializers.ModelSerializer):
     user = CustomReadOnlyUserSerializer(read_only=True)