(quality) refactoring cart add/remove/set_quantity item total compute

app/services/cart/add_item_service.rb

@@ -15,13 +15,13 @@ class Cart::AddItemService
     if item.nil?
       item = order.order_items.new(quantity: quantity, orderable: orderable, amount: orderable.amount || 0)
     else
-      item.quantity += quantity.to_i
+      item.quantity += quantity
     end
     raise Cart::OutStockError if item.quantity > orderable.stock['external']
 
-    order.total += (item.amount * item.quantity.to_i) unless item.is_offered
     ActiveRecord::Base.transaction do
       item.save
+      Cart::UpdateTotalService.new.call(order)
       order.save
     end
     order.reload

app/services/cart/find_or_create_service.rb

@@ -18,6 +18,7 @@ class Cart::FindOrCreateService
       clean_old_cart if @user
       @order.update(statistic_profile_id: @user.statistic_profile.id) if @order.statistic_profile_id.nil? && @user&.member?
       @order.update(operator_profile_id: @user.invoicing_profile.id) if @order.operator_profile_id.nil? && @user&.privileged?
+      Cart::UpdateTotalService.new.call(@order)
       return @order
     end
 

app/services/cart/refresh_item_service.rb

@@ -9,11 +9,10 @@ class Cart::RefreshItemService
 
     raise ActiveRecord::RecordNotFound if item.nil?
 
-    order.total -= (item.amount * item.quantity.to_i) unless item.is_offered
     item.amount = orderable.amount || 0
-    order.total += (item.amount * item.quantity.to_i) unless item.is_offered
     ActiveRecord::Base.transaction do
       item.save
+      Cart::UpdateTotalService.new.call(order)
       order.save
     end
     order.reload

app/services/cart/remove_item_service.rb

@@ -7,9 +7,9 @@ class Cart::RemoveItemService
 
     raise ActiveRecord::RecordNotFound if item.nil?
 
-    order.total -= (item.amount * item.quantity.to_i) unless item.is_offered
     ActiveRecord::Base.transaction do
       item.destroy!
+      Cart::UpdateTotalService.new.call(order)
       order.save
     end
     order.reload

app/services/cart/set_offer_service.rb

@@ -7,14 +7,10 @@ class Cart::SetOfferService
 
     raise ActiveRecord::RecordNotFound if item.nil?
 
-    if !item.is_offered && is_offered
-      order.total -= (item.amount * item.quantity)
-    elsif item.is_offered && !is_offered
-      order.total += (item.amount * item.quantity)
-    end
     item.is_offered = is_offered
     ActiveRecord::Base.transaction do
       item.save
+      Cart::UpdateTotalService.new.call(order)
       order.save
     end
     order.reload

app/services/cart/set_quantity_service.rb

@@ -13,10 +13,9 @@ class Cart::SetQuantityService
 
     raise ActiveRecord::RecordNotFound if item.nil?
 
-    different_quantity = quantity.to_i - item.quantity
-    order.total += (item.amount * different_quantity) unless item.is_offered
     ActiveRecord::Base.transaction do
       item.update(quantity: quantity.to_i)
+      Cart::UpdateTotalService.new.call(order)
       order.save
     end
     order.reload

app/services/cart/update_total_service.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+# Provides methods for update total of cart
+class Cart::UpdateTotalService
+  def call(order)
+    total = 0
+    order.order_items.each do |item|
+      total += (item.amount * item.quantity) unless item.is_offered
+    end
+    order.total = total
+    order.save
+    order
+  end
+end