Dynamic payment modifier valid option updates

shop/forms/checkout.py

@@ -9,7 +9,7 @@
 from django.utils.functional import cached_property
 
 from djng.styling.bootstrap3.forms import Bootstrap3ModelForm
-from djng.styling.bootstrap3.widgets import RadioSelect, RadioFieldRenderer, CheckboxInput
+from djng.styling.bootstrap3.widgets import RadioSelect, RadioFieldRenderer, CheckboxInput, RadioChoiceInput
 
 from shop.models.address import ShippingAddressModel, BillingAddressModel
 from shop.models.customer import CustomerModel
@@ -278,11 +278,28 @@ def set_address(self, cart, instance):
         cart.billing_address = instance if not self['use_primary_address'].value() else None
 
 
+class ValueInsertRadioChoiceInput(RadioChoiceInput):
+    """replaces '$value$' with the input field value in all string attributes"""
+    def tag(self, attrs=None):
+        attrs = attrs or self.attrs
+        for key, value in attrs.items():
+            if isinstance(value, str):
+                attrs[key] = value.replace('$value$', self.choice_value)
+        return super(ValueInsertRadioChoiceInput, self).tag(attrs)
+
+
+class ValueInsertRenderer(RadioFieldRenderer):
+    choice_input_class = ValueInsertRadioChoiceInput
+
+
 class PaymentMethodForm(DialogForm):
+    # from 2nd element of prefix used, always in response after 'data'
+    # is assigned using `$rootScope.data = response.data;`
     scope_prefix = 'data.payment_method'
 
     payment_modifier = fields.ChoiceField(label=_("Payment Method"),
-        widget=RadioSelect(renderer=RadioFieldRenderer, attrs={'ng-change': 'upload()'})
+        widget=RadioSelect(renderer=ValueInsertRenderer, attrs={'ng-change': 'upload()',
+            'ng-disabled': "$root.data.payment_method.choices.indexOf('$value$') === -1"})
     )
 
     def __init__(self, *args, **kwargs):
@@ -309,6 +326,15 @@ def form_factory(cls, request, data, cart):
                 payment_extra_data=data.get('payment_data', {}))
         return payment_method_form
 
+    def get_response_data(self):
+        """
+        Override default that returns nothing.
+        Add 'choices' payment modifier list for dynamic client-side disable
+        Must match the __init__ choices, otherwise validation will differ between server & client
+        """
+        choices = [choice[0] for choice in self.base_fields['payment_modifier'].choices]
+        return {'choices': choices}
+
 
 class ShippingMethodForm(DialogForm):
     scope_prefix = 'data.shipping_method'

shop/modifiers/base.py

@@ -135,11 +135,15 @@ def get_choice(self):
         """
         raise NotImplemented("Must be implemented by the inheriting class")
 
-    def is_active(self, cart):
+    def is_active(self, cart, request=None):
         """
         Returns true if this payment modifier is active.
+        Deprecation: calls should always supply a request so that '=None' can be removed
         """
-        return cart.extra.get('payment_modifier') == self.identifier
+        try:
+            return request.data['payment_method']['payment_modifier'] == self.identifier
+        except (AttributeError, KeyError):
+            return cart.extra.get('payment_modifier') == self.identifier
 
     def is_disabled(self, cart):
         """
@@ -167,11 +171,15 @@ def get_choice(self):
         """
         raise NotImplemented("Must be implemented by the inheriting class")
 
-    def is_active(self, cart):
+    def is_active(self, cart, request=None):
         """
         Returns true if this shipping modifier is active.
+        Deprecation: calls should always supply a request so that '=None' can be removed
         """
-        return cart.extra.get('shipping_modifier') == self.identifier
+        try:
+            return request.data['shipping_method']['shipping_modifier'] == self.identifier
+        except (AttributeError, KeyError):
+            return cart.extra.get('shipping_modifier') == self.identifier
 
     def is_disabled(self, cart):
         """

shop/static/shop/js/dialogs.js

@@ -40,6 +40,7 @@ djangoShopModule.controller('DialogController',
 			}
 			$rootScope.cart = response.cart;
 			$rootScope.checkout_summary = response.checkout_summary;
+			$rootScope.data = response.data;
 		}).error(function(errors) {
 			console.error("Unable to upload checkout forms:");
 			console.log(errors);

shop/views/checkout.py

@@ -67,7 +67,9 @@ def upload(self, request):
         # save data, get text representation and collect potential errors
         errors, checkout_summary, response_data = {}, {}, {'$valid': True}
         with transaction.atomic():
+            # only validates the relevant submitted checkout page form data
             for form_class, data in dialog_data:
+                # payment & shipping method forms call cart.update(request) which runs all modifiers
                 form = form_class.form_factory(request, data, cart)
                 if form.is_valid():
                     # empty error dict forces revalidation by the client side validation
@@ -85,8 +87,9 @@ def upload(self, request):
                     response_data[key] = update_data
             cart.save()
 
-        # add possible form errors for giving feedback to the customer
+        # produces a response with correct cart contents by running all modifiers via cart.update(request)
         response = self.list(request)
+        # adds the rest of the data for the checkout forms including customer feedback errors
         response.data.update(errors=errors, checkout_summary=checkout_summary, data=response_data)
         return response