Add custom base controller

The controller code we were using relied on a patch to Solidus[1] that will
only be released with Solidus 4.2. We want to be compatible with Solidus
4 though, so we're incorporating that patch into our own BaseController
  and use that instead of Solidus' ResourceController.

[1] solidusio#5219

friendly_promotions/app/controllers/solidus_friendly_promotions/admin/base_controller.rb

@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+module SolidusFriendlyPromotions
+  module Admin
+    class BaseController < Spree::Admin::ResourceController
+      def parent
+        @parent ||= self.class.parent_data[:model_class]
+          .includes(self.class.parent_data[:includes])
+          .find_by!(self.class.parent_data[:find_by] => params["#{parent_model_name}_id"])
+        instance_variable_set("@#{parent_model_name}", @parent)
+      rescue ActiveRecord::RecordNotFound => e
+        resource_not_found(flash_class: e.model.constantize, redirect_url: routes_proxy.polymorphic_url([:admin, parent_model_name.pluralize.to_sym]))
+      end
+
+      def new_object_url(options = {})
+        if parent?
+          routes_proxy.new_polymorphic_url([:admin, parent, model_class], options)
+        else
+          routes_proxy.new_polymorphic_url([:admin, model_class], options)
+        end
+      end
+
+      def edit_object_url(object, options = {})
+        if parent?
+          routes_proxy.polymorphic_url([:edit, :admin, parent, object], options)
+        else
+          routes_proxy.polymorphic_url([:edit, :admin, object], options)
+        end
+      end
+
+      def object_url(object = nil, options = {})
+        target = object || @object
+
+        if parent?
+          routes_proxy.polymorphic_url([:admin, parent, target], options)
+        else
+          routes_proxy.polymorphic_url([:admin, target], options)
+        end
+      end
+
+      def collection_url(options = {})
+        if parent?
+          routes_proxy.polymorphic_url([:admin, parent, model_class], options)
+        else
+          routes_proxy.polymorphic_url([:admin, model_class], options)
+        end
+      end
+
+      def routes_proxy
+        solidus_friendly_promotions
+      end
+    end
+  end
+end

friendly_promotions/app/controllers/solidus_friendly_promotions/admin/promotion_categories_controller.rb

@@ -2,16 +2,12 @@
 
 module SolidusFriendlyPromotions
   module Admin
-    class PromotionCategoriesController < Spree::Admin::ResourceController
+    class PromotionCategoriesController < BaseController
       private
 
       def model_class
         SolidusFriendlyPromotions::PromotionCategory
       end
-
-      def routes_proxy
-        solidus_friendly_promotions
-      end
     end
   end
 end

friendly_promotions/app/controllers/solidus_friendly_promotions/admin/promotion_code_batches_controller.rb

@@ -2,7 +2,7 @@
 
 module SolidusFriendlyPromotions
   module Admin
-    class PromotionCodeBatchesController < Spree::Admin::ResourceController
+    class PromotionCodeBatchesController < BaseController
       belongs_to "solidus_friendly_promotions/promotion"
 
       create.after :build_promotion_code_batch

friendly_promotions/app/controllers/solidus_friendly_promotions/admin/promotion_codes_controller.rb

@@ -4,7 +4,7 @@
 
 module SolidusFriendlyPromotions
   module Admin
-    class PromotionCodesController < Spree::Admin::ResourceController
+    class PromotionCodesController < BaseController
       before_action :load_promotion
 
       def index

friendly_promotions/app/controllers/solidus_friendly_promotions/admin/promotions_controller.rb

@@ -2,7 +2,7 @@
 
 module SolidusFriendlyPromotions
   module Admin
-    class PromotionsController < ::Spree::Admin::ResourceController
+    class PromotionsController < BaseController
       before_action :load_data
 
       helper "solidus_friendly_promotions/admin/promotion_rules"
@@ -59,10 +59,6 @@ def load_data
       def location_after_save
         solidus_friendly_promotions.edit_admin_promotion_url(@promotion)
       end
-
-      def routes_proxy
-        solidus_friendly_promotions
-      end
     end
   end
 end