Refactor to reveal how we load enterprises in shop

By sticking to Rails conventions we make it more obvious how (badly) we
are loading enterprises in EnterprisesController#shop and shed some
light on the obscure InjectionHelper.

This will also make it easier to improve its performance in the future as
it's among the top offenders. See https://www.skylight.io/app/applications/ibo3NOqCYMnq/1545851520/1d/endpoints/EnterprisesController%23shop?responseType=html

app/controllers/enterprises_controller.rb

@@ -7,13 +7,28 @@ class EnterprisesController < BaseController
 
   # These prepended filters are in the reverse order of execution
   prepend_before_filter :set_order_cycles, :require_distributor_chosen, :reset_order, only: :shop
-  before_filter :check_stock_levels, :set_noindex_meta_tag, only: :shop
 
   before_filter :clean_permalink, only: :check_permalink
   before_filter :enable_embedded_shopfront
 
   respond_to :js, only: :permalink_checker
 
+  def shop
+    check_stock_levels
+    set_noindex_meta_tag
+
+    order_cycles = if current_order_cycle
+                     [current_order_cycle]
+                   else
+                     OrderCycle.not_closed.with_distributor(current_distributor)
+                   end
+
+    enterprises = current_distributor.plus_relatives_and_oc_producers(order_cycles).activated.includes(address: :state).all
+    enterprises = inject_json_ams('enterprises', enterprises)
+
+    render locals: { enterprises: enterprises }
+  end
+
   def relatives
     set_enterprise
 
@@ -88,4 +103,14 @@ class EnterprisesController < BaseController
   def set_noindex_meta_tag
     @noindex_meta_tag = true unless current_distributor.visible?
   end
+
+  def inject_json_ams(name, object)
+    options = {
+      each_serializer: Api::EnterpriseSerializer,
+      data: OpenFoodNetwork::EnterpriseInjectionData.new
+    }
+    serializer_instance = ActiveModel::ArraySerializer.new(object, options)
+
+    { name: name, json: serializer_instance.to_json }
+  end
 end

app/helpers/injection_helper.rb

@@ -14,15 +14,6 @@ module InjectionHelper
     inject_json_ams "enterprises", current_distributor.relatives_including_self.activated.includes(address: :state).all, Api::EnterpriseSerializer, enterprise_injection_data
   end
 
-  def inject_shop_enterprises
-    ocs = if current_order_cycle
-            [current_order_cycle]
-          else
-            OrderCycle.not_closed.with_distributor(current_distributor)
-          end
-    inject_json_ams "enterprises", current_distributor.plus_relatives_and_oc_producers(ocs).activated.includes(address: :state).all, Api::EnterpriseSerializer, enterprise_injection_data
-  end
-
   def inject_group_enterprises
     inject_json_ams "group_enterprises", @group.enterprises.activated.all, Api::EnterpriseSerializer, enterprise_injection_data
   end

app/views/enterprises/shop.html.haml

@@ -5,7 +5,7 @@
 - content_for(:image) do
   = current_distributor.logo.url
 
-= inject_shop_enterprises
+= render partial: 'json/injection_ams', locals: enterprises
 
 %shop.darkswarm
   - if @shopfront_layout == 'embedded'