Show a modal when available stock levels have reduced

app/assets/javascripts/darkswarm/services/cart.js.coffee

@@ -1,4 +1,4 @@
-Darkswarm.factory 'Cart', (CurrentOrder, Variants, $timeout, $http, storage)->
+Darkswarm.factory 'Cart', (CurrentOrder, Variants, $timeout, $http, $modal, $rootScope, storage)->
   # Handles syncing of current cart/order state to server
   new class Cart
     dirty: false
@@ -41,21 +41,30 @@ Darkswarm.factory 'Cart', (CurrentOrder, Variants, $timeout, $http, storage)->
         @update_running = false
 
     compareAndNotifyStockLevels: (stockLevels) =>
+      scope = $rootScope.$new(true)
+      scope.variants = []
+
+      # TODO: These changes to quantity/max_quantity trigger another cart update, which
+      #       is unnecessary.
+
       for li in @line_items_present()
         if !stockLevels[li.variant.id]?
-          alert "Variant out of stock: #{li.variant.id}"
           li.quantity = 0
           li.max_quantity = 0 if li.max_quantity?
           li.variant.count_on_hand = 0
+          scope.variants.push li.variant
         else
           if stockLevels[li.variant.id].quantity < li.quantity
-            alert "Variant quantity reduced: #{li.variant.id}"
             li.quantity = stockLevels[li.variant.id].quantity
+            scope.variants.push li.variant
           if stockLevels[li.variant.id].max_quantity < li.max_quantity
-            alert "Variant max_quantity reduced: #{li.variant.id}"
             li.max_quantity = stockLevels[li.variant.id].max_quantity
+            scope.variants.push li.variant
           li.variant.count_on_hand = stockLevels[li.variant.id].on_hand
 
+      if scope.variants.length > 0
+        $modal.open(templateUrl: "out_of_stock.html", scope: scope, windowClass: 'out-of-stock-modal')
+
     popQueue: =>
       @update_enqueued = false
       @scheduleUpdate()

app/assets/javascripts/templates/out_of_stock.html.haml

@@ -0,0 +1,10 @@
+%h3 Reduced stock available
+
+%p While you've been shopping, the stock levels for one or more of the products in your cart have reduced. Here's what's changed:
+
+%p{'ng-repeat' => "v in variants"}
+  %em {{ v.name_to_display }} - {{ v.unit_to_display }}
+  %span{'ng-if' => "v.count_on_hand == 0"}
+    is now out of stock.
+  %span{'ng-if' => "v.count_on_hand > 0"}
+    now only has {{ v.count_on_hand }} remaining.

app/controllers/spree/orders_controller_decorator.rb

@@ -51,12 +51,11 @@ Spree::OrdersController.class_eval do
         [li.variant.id,
          {quantity: li.quantity,
           max_quantity: li.max_quantity,
-          on_hand: li.variant.on_hand}]
+          on_hand: wrap_json_infinity(li.variant.on_hand)}]
       end
     ]
   end
 
-
   def update_distribution
     @order = current_order(true)
 
@@ -135,4 +134,9 @@ Spree::OrdersController.class_eval do
     end
   end
 
+  # Rails to_json encodes Float::INFINITY as Infinity, which is not valid JSON
+  # Return it as a large integer (max 32 bit signed int)
+  def wrap_json_infinity(n)
+    n == Float::INFINITY ? 2147483647 : n
+  end
 end

spec/controllers/spree/orders_controller_spec.rb

@@ -69,6 +69,14 @@ describe Spree::OrdersController do
       it "returns a hash with variant id, quantity, max_quantity and stock on hand" do
         controller.stock_levels.should == {v.id => {quantity: 2, max_quantity: 3, on_hand: 4}}
       end
+
+      describe "encoding Infinity" do
+        let!(:v) { create(:variant, on_demand: true, count_on_hand: 0) }
+
+        it "encodes Infinity as a large, finite integer" do
+          controller.stock_levels.should == {v.id => {quantity: 2, max_quantity: 3, on_hand: 2147483647}}
+        end
+      end
     end
   end
 

spec/features/consumer/shopping/shopping_spec.rb

@@ -243,14 +243,13 @@ feature "As a consumer I want to shop with a distributor", js: true do
           variant.update_attributes! on_hand: 0
 
           # -- Messaging
-          alert_message = accept_alert do
-            fill_in "variants[#{variant.id}]", with: '1'
-            wait_until { !cart_dirty }
-          end
+          fill_in "variants[#{variant.id}]", with: '1'
+          wait_until { !cart_dirty }
 
-          # TODO: This will be a modal
-          expect(alert_message).to be
-          puts alert_message
+          within(".out-of-stock-modal") do
+            page.should have_content "stock levels for one or more of the products in your cart have reduced"
+            page.should have_content "#{product.name} - #{variant.unit_to_display} is now out of stock."
+          end
 
           # -- Page updates
           # Update amount in cart
@@ -274,14 +273,13 @@ feature "As a consumer I want to shop with a distributor", js: true do
             variant.update_attributes! on_hand: 0
 
             # -- Messaging
-            alert_message = accept_alert do
-              fill_in "variant_attributes[#{variant.id}][max_quantity]", with: '1'
-              wait_until { !cart_dirty }
-            end
+            fill_in "variant_attributes[#{variant.id}][max_quantity]", with: '1'
+            wait_until { !cart_dirty }
 
-            # TODO: This will be a modal
-            expect(alert_message).to be
-            puts alert_message
+            within(".out-of-stock-modal") do
+              page.should have_content "stock levels for one or more of the products in your cart have reduced"
+              page.should have_content "#{product.name} - #{variant.unit_to_display} is now out of stock."
+            end
 
             # -- Page updates
             # Update amount in cart