Reworking order populator and controller to handle replacement of line items rather than addition

app/controllers/spree/orders_controller_decorator.rb

@@ -21,22 +21,15 @@ Spree::OrdersController.class_eval do
     end
   end
 
-  # Patch Orders#populate to populate multi_cart (if enabled)
+  # Patch populate to be Ajax
   def populate
-    if OpenFoodNetwork::FeatureToggle.enabled? :multi_cart
-      populate_cart params.slice(:products, :variants, :quantity, :distributor_id, :order_cycle_id)
-    end
     populator = Spree::OrderPopulator.new(current_order(true), current_currency)
-    if populator.populate(params.slice(:products, :variants, :quantity))
-
+    if populator.populate(params.slice(:products, :variants, :quantity), true)
       fire_event('spree.cart.add')
       fire_event('spree.order.contents_changed')
-      respond_with(@order) do |format|
-        format.html { redirect_to cart_path }
-      end
+      render json: true, status: 200
     else
-      flash[:error] = populator.errors.full_messages.join(" ")
-      redirect_to :back
+      render json: false, status: 402
     end
   end
 

app/models/spree/order_populator_decorator.rb

@@ -1,19 +1,27 @@
 Spree::OrderPopulator.class_eval do
-  def populate_with_distribution_validation(from_hash)
+  def populate(from_hash, overwrite = false)
     @distributor, @order_cycle = distributor_and_order_cycle
-
     # Refactor: We may not need this validation - we can't change distribution here, so
     # this validation probably can't fail
     if !distribution_can_supply_products_in_cart(@distributor, @order_cycle)
       errors.add(:base, "That distributor or order cycle can't supply all the products in your cart. Please choose another.")
     end
 
-    populate_without_distribution_validation(from_hash) if valid?
+    if valid? 
+      @order.with_lock do
+        @order.empty! if overwrite
+        from_hash[:products].each do |product_id,variant_id|
+          attempt_cart_add(variant_id, from_hash[:quantity])
+        end if from_hash[:products]
+
+        from_hash[:variants].each do |variant_id, quantity|
+          attempt_cart_add(variant_id, quantity)
+        end if from_hash[:variants]
+      end
+    end
 
     valid?
   end
-  alias_method_chain :populate, :distribution_validation
-
 
   # Copied from Spree::OrderPopulator, with additional validations added
   def attempt_cart_add(variant_id, quantity)

spec/controllers/spree/orders_controller_spec.rb

@@ -66,6 +66,26 @@ describe Spree::OrdersController do
         spree_post :populate, :variants => {p.master.id => 1}, :variant_attributes => {p.master.id => {:max_quantity => 3}}
       end.to change(Spree::LineItem, :count).by(1)
     end
+
+    it "returns HTTP success when successful" do
+      Spree::OrderPopulator.stub(:new).and_return(populator = mock())
+      populator.stub(:populate).and_return true
+      xhr :post, :populate, use_route: :spree, format: :json
+      response.status.should == 200
+    end
+
+    it "returns failure when unsuccessful" do
+      Spree::OrderPopulator.stub(:new).and_return(populator = mock())
+      populator.stub(:populate).and_return false
+      xhr :post, :populate, use_route: :spree, format: :json
+      response.status.should == 402
+    end
+
+    it "tells populator to overwrite" do
+      Spree::OrderPopulator.stub(:new).and_return(populator = mock())
+      populator.should_receive(:populate).with({}, true)
+      xhr :post, :populate, use_route: :spree, format: :json
+    end
   end
 
   context "removing line items from cart" do

spec/models/spree/order_populator_spec.rb

@@ -4,23 +4,36 @@ module Spree
   describe OrderPopulator do
     let(:order) { double(:order, id: 123) }
     let(:currency) { double(:currency) }
-    let(:params) { double(:params) }
+    let(:params) { {} }
     let(:distributor) { double(:distributor) }
     let(:order_cycle) { double(:order_cycle) }
     let(:op) { OrderPopulator.new(order, currency) }
 
     describe "populate" do
-
-      it "checks that distribution can supply all products in the cart" do
+      before do
         op.should_receive(:distributor_and_order_cycle).
           and_return([distributor, order_cycle])
+      end
+      it "checks that distribution can supply all products in the cart" do
         op.should_receive(:distribution_can_supply_products_in_cart).
           with(distributor, order_cycle).and_return(false)
-        op.should_receive(:populate_without_distribution_validation).never
 
         op.populate(params).should be_false
         op.errors.to_a.should == ["That distributor or order cycle can't supply all the products in your cart. Please choose another."]
       end
+      
+      it "empties the order if override is true" do
+        op.stub(:distribution_can_supply_products_in_cart).and_return true
+        order.stub(:with_lock).and_yield
+        order.should_receive(:empty!)
+        op.populate(params, true)
+      end
+
+      it "locks the order" do
+        op.stub(:distribution_can_supply_products_in_cart).and_return(true)
+        order.should_receive(:with_lock)
+        op.populate(params, true)
+      end
     end
 
     describe "attempt_cart_add" do