Weight based mail_value_calculator

Compute shipping/franking cost based on sum of weight in package

app/models/spree/calculator/sysmocom_mail_value_calculator.rb

@@ -12,6 +12,14 @@ module Spree
         item_total
     end
 
+    def total_weight(o)
+	weight = 0
+	o.line_items.each do |li|
+          weight += li.quantity * li.variant.weight
+        end
+        return weight
+    end
+
     def extract_iso_code(o)
         if o.kind_of?(Spree::Shipment)
             return o.address.country.iso
@@ -19,26 +27,60 @@ module Spree
         return o.ship_address.country.iso
     end
 
+
+    def postage_for_weight_DE(weight)
+        # Grossbrief Einschreiben: 3.95;  Maxibrief Einschreiben: 5.10 / 7.30
+        if weight < 500
+          return 3.95
+        elsif weight < 1000
+          return 5.10
+        elsif weight < 2000
+          return 7.30
+	else
+	  return 99999
+        end
+    end
+
+    def postage_for_weight_INTL(weight)
+        # Warenpost International Unterschrift S: 6.20 / M: 9.50 / L: 19.50
+        if weight < 500
+          return 6.20
+        elsif weight < 1000
+          return 9.50
+        elsif weight < 2000
+          return 19.50
+	else
+	  return 99999
+        end
+    end
+
+    def self.available?(object)
+        # Letters have a maximum weight of 2kg
+        weight = total_weight(object)
+        if weight < 2000
+          true
+        else
+          false
+        end
+    end
+
     def compute(object)
         # This could be more than an order but not right now
         shipping_value = total_value_no_tax(object)
+        weight = total_weight(object)
         iso_code = extract_iso_code(object)
 
-        # Warenpost International Unterschrift S: 6.20 / M: 9.50 / L: 19.50
-        base = 9.5
         if iso_code == 'DE'
-          # Grossbrief Einschreiben: 3.95;  Maxibrief Einschreiben: 5.10 / 7.30
-          base = 5.1
+          base = postage_for_weight_DE(weight)
+        else
+          base = postage_for_weight_INTL(weight)
+          # We need to add insurance..
+          if shipping_value > 20
+            # Wert Intenational: 2.50 + 2 EUR je 100 EUR Haftungssumme
+            base += 2.5 + (((shipping_value.round / 100) + 1) * 2)
+          end
         end
-
-        # We need to add insurance..
-        if shipping_value < 20
-          # Plain registered letter
-          return base
-        end
-
-        # Wert Intenational: 2.50 + 2 EUR je 100 EUR Haftungssumme
-        return base + 2.5 + (((shipping_value.round / 100) + 1) * 2)
+        return base
     end
 
   end