Finish refactoring of Standing Order Updaters, replacing with form class used by controller

app/forms/standing_order_form.rb

@@ -28,6 +28,10 @@ class StandingOrderForm
         update_payment_for(order) if payment_method_id_changed?
       end
 
+      changed_standing_line_items.each do |sli|
+        updateable_line_items(sli).update_all(quantity: sli.quantity)
+      end
+
       standing_order.save
     end
   end
@@ -42,7 +46,8 @@ class StandingOrderForm
   private
 
   def future_and_undated_orders
-    orders.joins(:order_cycle).merge(OrderCycle.not_closed)
+    return @future_and_undated_orders unless @future_and_undated_orders.nil?
+    @future_and_undated_orders = orders.joins(:order_cycle).merge(OrderCycle.not_closed)
   end
 
   def create_order_for(order_cycle_id)
@@ -92,4 +97,16 @@ class StandingOrderForm
   def uninitialised_order_cycle_ids
     order_cycles.pluck(:id) - orders.map(&:order_cycle_id)
   end
+
+  def changed_standing_line_items
+    standing_line_items.select(&:changed?)
+  end
+
+  def updateable_line_items(sli)
+    line_items_from_future_and_undated_orders(sli.variant_id).where(quantity: sli.quantity_was)
+  end
+
+  def line_items_from_future_and_undated_orders(variant_id)
+    Spree::LineItem.where(order_id: future_and_undated_orders, variant_id: variant_id)
+  end
 end

app/models/standing_line_item.rb

@@ -1,8 +1,4 @@
-require 'open_food_network/standing_line_item_updater'
-
 class StandingLineItem < ActiveRecord::Base
-  include OpenFoodNetwork::StandingLineItemUpdater
-
   belongs_to :standing_order, inverse_of: :standing_line_items
   belongs_to :variant, class_name: 'Spree::Variant'
 
@@ -10,8 +6,6 @@ class StandingLineItem < ActiveRecord::Base
   validates :variant, presence: true
   validates :quantity, { presence: true, numericality: { only_integer: true } }
 
-  # before_save :update_line_items! # In OpenFoodNetwork::StandingLineItemUpdater
-
   def available_from?(shop, schedule)
     Spree::Variant.joins(exchanges: { order_cycle: :schedules})
     .where(id: variant_id, schedules: { id: schedule}, exchanges: { incoming: false, receiver_id: shop })

lib/open_food_network/standing_line_item_updater.rb

@@ -1,35 +0,0 @@
-module OpenFoodNetwork
-  module StandingLineItemUpdater
-
-    attr_accessor :altered_orders
-
-    def update_line_items!
-      altered_orders ||= []
-      attr_names.each do |attr_name|
-        unaltered_line_items(attr_name).update_all(:"#{attr_name}" => send(attr_name))
-        if altered_line_items(attr_name).any?
-          altered_orders |= altered_line_items(attr_name).map(&:order)
-        end
-      end
-    end
-
-    private
-
-    def attr_names
-      [:quantity]
-    end
-
-    def unaltered_line_items(attr_name)
-      return line_items_from_future_and_undated_orders unless persisted?
-      line_items_from_future_and_undated_orders.where("#{attr_name} = (?)", send("#{attr_name}_was"))
-    end
-
-    def altered_line_items(attr_name)
-      line_items_from_future_and_undated_orders - unaltered_line_items(attr_name)
-    end
-
-    def line_items_from_future_and_undated_orders
-      Spree::LineItem.where(order_id: standing_order.future_and_undated_orders, variant_id: variant_id)
-    end
-  end
-end

spec/forms/standing_order_form_spec.rb

@@ -140,10 +140,13 @@ module OpenFoodNetwork
 
     describe "changing the quantity of a line item" do
       let(:standing_order) { create(:standing_order_with_items) }
+      let(:sli) { standing_order.standing_line_items.first }
+      let(:params) { { standing_line_items_attributes: [ { id: sli.id, quantity: 4} ] } }
+      let(:form) { StandingOrderForm.new(standing_order, params) }
+
+      before { form.save }
 
       it "updates the quantity on all orders" do
-        sli = standing_order.standing_line_items.first
-        sli.update_attribute(:quantity, 4)
         line_items = Spree::LineItem.where(order_id: standing_order.orders, variant_id: sli.variant_id)
         expect(line_items.map(&:quantity)).to eq [4]
       end