wikimo · December 6, 2016 06:29 · Dec 6, 2016
diff --git a/flat_with_products.rb b/flat_with_products.rb
@@ -0,0 +1,34 @@
+require_dependency 'spree/calculator'
+
+module Spree
+  class Calculator::FlatWithProducts < Calculator
+    preference :amount, :decimal, default: 0
+    preference :currency, :string, default: ->{ Spree::Config[:currency] }
+
+    def self.description
+      Spree.t(:flat_with_products)
+    end
+
+    def compute(object=nil)
+      if object && preferred_currency.upcase == object.currency.upcase
+        # get promotion and related products
+        promotion = Spree::Promotion.find_by_description '1A/1B'
+        promotion_products =  promotion.products
+
+        # check line_items if exist in promotion
+        product_nums = []
+        promotion_products.each do |check_product|
+          object.line_items.each do |item|
+            if item.variant_id == check_product.id
+              product_nums << item.quantity
+            end
+          end
+        end
+
+        return product_nums.min * preferred_amount if product_nums.size > 0
+      end
+
+      0
+    end
+  end
+end