Make total number of products in exchange work again.

Currently we are just loading the products from the server and count them.
This can be improved easily in two ways:
- we can switch this to a specific product count call to the server so that we dont load all products all the time
- or we paginate the products result and fetch the total_number from the payload of the first page.

app/assets/javascripts/admin/order_cycles/controllers/incoming_controller.js.coffee

@@ -1,5 +1,23 @@
 angular.module('admin.orderCycles').controller 'AdminOrderCycleIncomingCtrl', ($scope, $controller, $location, Enterprise, ocInstance) ->
   $controller('AdminOrderCycleExchangesCtrl', {$scope: $scope, ocInstance: ocInstance, $location: $location})
 
-  $scope.enterpriseTotalVariants = (enterprise) ->
-    Enterprise.totalVariants(enterprise)
+  $scope.view = 'incoming'
+
+  $scope.exchangeTotalVariants = (exchange) ->
+    return unless this.enterprises? && this.enterprises[exchange.enterprise_id]?
+
+    enterprise = this.enterprises[exchange.enterprise_id]
+    return enterprise.numVariants if enterprise.numVariants?
+
+    $scope.loadExchangeProducts(this, exchange)
+    return unless enterprise.supplied_products?
+
+    enterprise.numVariants = $scope.countVariants(enterprise.supplied_products)
+
+  $scope.countVariants = (products) ->
+    return 0 unless products
+
+    numVariants = 0
+    for product in products
+      numVariants += product.variants.length
+    numVariants

app/assets/javascripts/admin/order_cycles/controllers/order_cycle_exchanges_controller.js.coffee

@@ -44,10 +44,16 @@ angular.module('admin.orderCycles')
     $scope.removeDistributionOfVariant = (variant_id) ->
       OrderCycle.removeDistributionOfVariant(variant_id)
 
-    # Load exchange data
-    initPanel = (scope) ->
-      Product.index {exchange_id: scope.exchange.id, enterprise_id: scope.exchange.enterprise_id}, (products) ->
-        scope.enterprises[scope.exchange.enterprise_id].supplied_products = products
+    # Load exchange products
+    $scope.loadExchangeProducts = (scope, exchange) ->
+      return if scope.enterprises[exchange.enterprise_id].supplied_products_fetched?
+      scope.enterprises[exchange.enterprise_id].supplied_products_fetched = true
+
+      Product.index {exchange_id: exchange.id, enterprise_id: exchange.enterprise_id}, (products) ->
+        scope.enterprises[exchange.enterprise_id].supplied_products = products
+
+    initPanel = (scope, exchange) ->
+      scope.loadExchangeProducts(scope, scope.exchange)
 
     # Register listener to capture first toggle open of the products panel
     exchangeProdutsInitialized = []

app/assets/javascripts/admin/order_cycles/services/enterprise.js.coffee

@@ -35,13 +35,4 @@ angular.module('admin.orderCycles').factory('Enterprise', ($resource) ->
         variant.id for variant in product.variants
       else
         [product.master_id]
-
-    totalVariants: (enterprise) ->
-      numVariants = 0
-
-      if enterprise
-        counts = for product in enterprise.supplied_products
-          numVariants += if product.variants.length == 0 then 1 else product.variants.length
-
-      numVariants
   })