Extract application of enterprise fees as adjustments into its own class

app/models/exchange.rb

@@ -35,6 +35,10 @@ class Exchange < ActiveRecord::Base
     receiver == order_cycle.coordinator
   end
 
+  def role
+    incoming? ? 'supplier' : 'distributor'
+  end
+
   def to_h(core=false)
     h = attributes.merge({ 'variant_ids' => variant_ids.sort, 'enterprise_fee_ids' => enterprise_fee_ids.sort })
     h.reject! { |k| %w(id order_cycle_id created_at updated_at).include? k } if core

app/models/order_cycle.rb

@@ -1,3 +1,5 @@
+require 'open_food_network/enterprise_fee_applicator'
+
 class OrderCycle < ActiveRecord::Base
   belongs_to :coordinator, :class_name => 'Enterprise'
   has_and_belongs_to_many :coordinator_fees, :class_name => 'EnterpriseFee', :join_table => 'coordinator_fees'
@@ -144,12 +146,12 @@ class OrderCycle < ActiveRecord::Base
 
   # -- Fees
   def fees_for(variant, distributor)
-    enterprise_fees_for(variant, distributor).sum do |fee|
+    enterprise_fees_for(variant, distributor).sum do |applicator|
       # Spree's Calculator interface accepts Orders or LineItems,
       # so we meet that interface with a struct.
       # Amount is faked, this is a method on LineItem
       line_item = OpenStruct.new variant: variant, quantity: 1, amount: (variant.price) 
-      fee[:enterprise_fee].compute_amount(line_item)
+      applicator.enterprise_fee.compute_amount(line_item)
     end
   end
 
@@ -157,7 +159,7 @@ class OrderCycle < ActiveRecord::Base
     variant = line_item.variant
     distributor = line_item.order.distributor
 
-    enterprise_fees_for(variant, distributor).each { |fee| create_adjustment_for_fee line_item, fee[:enterprise_fee], fee[:label], fee[:role] }
+    enterprise_fees_for(variant, distributor).each { |applicator| applicator.create_line_item_adjustment(line_item) }
   end
 
   private
@@ -168,31 +170,17 @@ class OrderCycle < ActiveRecord::Base
 
     exchanges_carrying(variant, distributor).each do |exchange|
       exchange.enterprise_fees.each do |enterprise_fee|
-        role = exchange.incoming? ? 'supplier' : 'distributor'
-        fees << {enterprise_fee: enterprise_fee,
-                 label: adjustment_label_for(variant, enterprise_fee, role),
-                 role: role}
+        fees << OpenFoodNetwork::EnterpriseFeeApplicator.new(enterprise_fee, variant, exchange.role)
       end
     end
 
     coordinator_fees.each do |enterprise_fee|
-      fees << {enterprise_fee: enterprise_fee,
-               label: adjustment_label_for(variant, enterprise_fee, 'coordinator'),
-               role: 'coordinator'}
+      fees << OpenFoodNetwork::EnterpriseFeeApplicator.new(enterprise_fee, variant, 'coordinator')
     end
 
     fees
   end
 
-  def create_adjustment_for_fee(line_item, enterprise_fee, label, role)
-    a = enterprise_fee.create_locked_adjustment(label, line_item.order, line_item, true)
-    AdjustmentMetadata.create! adjustment: a, enterprise: enterprise_fee.enterprise, fee_name: enterprise_fee.name, fee_type: enterprise_fee.fee_type, enterprise_role: role
-  end
-
-  def adjustment_label_for(variant, enterprise_fee, role)
-    "#{variant.product.name} - #{enterprise_fee.fee_type} fee by #{role} #{enterprise_fee.enterprise.name}"
-  end
-
   def exchanges_carrying(variant, distributor)
     exchanges.to_enterprises([coordinator, distributor]).with_variant(variant)
   end

lib/open_food_network/enterprise_fee_applicator.rb

@@ -0,0 +1,16 @@
+module OpenFoodNetwork
+  class EnterpriseFeeApplicator < Struct.new(:enterprise_fee, :variant, :role)
+    def create_line_item_adjustment(line_item)
+      a = enterprise_fee.create_locked_adjustment(adjustment_label, line_item.order, line_item, true)
+      AdjustmentMetadata.create! adjustment: a, enterprise: enterprise_fee.enterprise, fee_name: enterprise_fee.name, fee_type: enterprise_fee.fee_type, enterprise_role: role
+    end
+
+
+    private
+
+    def adjustment_label
+      "#{variant.product.name} - #{enterprise_fee.fee_type} fee by #{role} #{enterprise_fee.enterprise.name}"
+    end
+  end
+end
+

spec/lib/open_food_network/enterprise_fee_applicator_spec.rb

@@ -0,0 +1,37 @@
+require 'open_food_network/enterprise_fee_applicator'
+
+module OpenFoodNetwork
+  describe EnterpriseFeeApplicator do
+    it "creates an adjustment for a line item" do
+      line_item = create(:line_item)
+      enterprise_fee = create(:enterprise_fee)
+      product = create(:simple_product)
+
+      efa = EnterpriseFeeApplicator.new enterprise_fee, product.master, 'role'
+      efa.stub(:adjustment_label) { 'label' }
+      efa.create_line_item_adjustment line_item
+
+      adjustment = Spree::Adjustment.last
+      adjustment.label.should == 'label'
+      adjustment.adjustable.should == line_item.order
+      adjustment.source.should == line_item
+      adjustment.originator.should == enterprise_fee
+      adjustment.should be_mandatory
+
+      md = adjustment.metadata
+      md.enterprise.should == enterprise_fee.enterprise
+      md.fee_name.should == enterprise_fee.name
+      md.fee_type.should == enterprise_fee.fee_type
+      md.enterprise_role.should == 'role'
+    end
+
+    it "makes adjustment labels" do
+      variant = double(:variant, product: double(:product, name: 'Bananas'))
+      enterprise_fee = double(:enterprise_fee, fee_type: 'packing', enterprise: double(:enterprise, name: 'Ballantyne'))
+
+      efa = EnterpriseFeeApplicator.new enterprise_fee, variant, 'distributor'
+
+      efa.send(:adjustment_label).should == "Bananas - packing fee by distributor Ballantyne"
+    end
+  end
+end

spec/models/exchange_spec.rb

@@ -62,6 +62,20 @@ describe Exchange do
     end
   end
 
+  describe "reporting its role" do
+    it "returns 'supplier' when it is an incoming exchange" do
+      e = Exchange.new
+      e.stub(:incoming?) { true }
+      e.role.should == 'supplier'
+    end
+
+    it "returns 'distributor' when it is an outgoing exchange" do
+      e = Exchange.new
+      e.stub(:incoming?) { false }
+      e.role.should == 'distributor'
+    end
+  end
+
   describe "scopes" do
     let(:supplier) { create(:supplier_enterprise) }
     let(:coordinator) { create(:distributor_enterprise) }

spec/models/order_cycle_spec.rb

@@ -348,9 +348,9 @@ describe OrderCycle do
     let(:line_item) { double(:line_item, variant: variant, order: order) }
 
     it "creates adjustment for each fee" do
-      fee = {enterprise_fee: 'ef', label: 'label', role: 'role'}
-      oc.should_receive(:enterprise_fees_for).with(variant, distributor) { [fee] }
-      oc.should_receive(:create_adjustment_for_fee).with(line_item, 'ef', 'label', 'role')
+      applicator = double(:enterprise_fee_applicator)
+      applicator.should_receive(:create_line_item_adjustment).with(line_item)
+      oc.should_receive(:enterprise_fees_for).with(variant, distributor) { [applicator] }
 
       oc.send(:create_adjustments_for, line_item)
     end
@@ -360,44 +360,16 @@ describe OrderCycle do
       ef1 = double(:enterprise_fee)
       ef2 = double(:enterprise_fee)
       ef3 = double(:enterprise_fee)
-      incoming_exchange = double(:exchange, enterprise_fees: [ef1], incoming?: true)
-      outgoing_exchange = double(:exchange, enterprise_fees: [ef2], incoming?: false)
+      incoming_exchange = double(:exchange, enterprise_fees: [ef1], role: 'supplier')
+      outgoing_exchange = double(:exchange, enterprise_fees: [ef2], role: 'distributor')
 
       oc.stub(:exchanges_carrying) { [incoming_exchange, outgoing_exchange] }
       oc.stub(:coordinator_fees) { [ef3] }
-      oc.stub(:adjustment_label_for) { 'label' }
 
       oc.send(:enterprise_fees_for, line_item.variant, distributor).should ==
-        [{enterprise_fee: ef1, label: 'label', role: 'supplier'},
-         {enterprise_fee: ef2, label: 'label', role: 'distributor'},
-         {enterprise_fee: ef3, label: 'label', role: 'coordinator'}]
-    end
-
-    it "creates an adjustment for a fee" do
-      line_item = create(:line_item)
-      enterprise_fee = create(:enterprise_fee)
-
-      oc.send(:create_adjustment_for_fee, line_item, enterprise_fee, 'label', 'role')
-
-      adjustment = Spree::Adjustment.last
-      adjustment.label.should == 'label'
-      adjustment.adjustable.should == line_item.order
-      adjustment.source.should == line_item
-      adjustment.originator.should == enterprise_fee
-      adjustment.should be_mandatory
-
-      md = adjustment.metadata
-      md.enterprise.should == enterprise_fee.enterprise
-      md.fee_name.should == enterprise_fee.name
-      md.fee_type.should == enterprise_fee.fee_type
-      md.enterprise_role.should == 'role'
-    end
-
-    it "makes adjustment labels" do
-      variant = double(:variant, product: double(:product, name: 'Bananas'))
-      enterprise_fee = double(:enterprise_fee, fee_type: 'packing', enterprise: double(:enterprise, name: 'Ballantyne'))
-
-      oc.send(:adjustment_label_for, variant, enterprise_fee, 'distributor').should == "Bananas - packing fee by distributor Ballantyne"
+        [OpenFoodNetwork::EnterpriseFeeApplicator.new(ef1, line_item.variant, 'supplier'),
+         OpenFoodNetwork::EnterpriseFeeApplicator.new(ef2, line_item.variant, 'distributor'),
+         OpenFoodNetwork::EnterpriseFeeApplicator.new(ef3, line_item.variant, 'coordinator')]
     end
   end