Paginate exchange products results

This commit breaks the OC page when there are more than 100 products in an exchange

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

@@ -11,5 +11,5 @@ angular.module('admin.orderCycles').factory('ExchangeProduct', ($resource) ->
     index: (params={}, callback=null) ->
       ExchangeProductResource.index params, (data) =>
         @loaded = true
-        (callback || angular.noop)(data)
+        (callback || angular.noop)(data.products)
   })

app/controllers/api/exchange_products_controller.rb

@@ -1,6 +1,9 @@
 # This controller lists products that can be added to an exchange
 module Api
   class ExchangeProductsController < Api::BaseController
+    DEFAULT_PAGE = 1
+    DEFAULT_PER_PAGE = 100
+
     skip_authorization_check only: [:index]
 
     # If exchange_id is present in the URL:
@@ -17,20 +20,17 @@ module Api
         load_data_from_other_params
       end
 
-      render_products
+      render_paginated_products products
     end
 
     private
 
-    def render_products
-      products = ExchangeProductsRenderer.
+    def products
+      ExchangeProductsRenderer.
         new(@order_cycle, spree_current_user).
-        exchange_products(@incoming, @enterprise)
-
-      render json: products,
-             each_serializer: Api::Admin::ForOrderCycle::SuppliedProductSerializer,
-             order_cycle: @order_cycle,
-             status: :ok
+        exchange_products(@incoming, @enterprise).
+        page(params[:page] || DEFAULT_PAGE).
+        per(params[:per_page] || DEFAULT_PER_PAGE)
     end
 
     def load_data_from_exchange
@@ -51,5 +51,27 @@ module Api
       end
       @incoming = params[:incoming]
     end
+
+    def render_paginated_products(products)
+      serializer = ActiveModel::ArraySerializer.new(
+        products,
+        each_serializer: Api::Admin::ForOrderCycle::SuppliedProductSerializer,
+        order_cycle: @order_cycle
+      )
+
+      render text: {
+        products: serializer,
+        pagination: pagination_data(products)
+      }.to_json
+    end
+
+    def pagination_data(results)
+      {
+        results: results.total_count,
+        pages: results.num_pages,
+        page: (params[:page] || DEFAULT_PAGE).to_i,
+        per_page: (params[:per_page] || DEFAULT_PER_PAGE).to_i
+      }
+    end
   end
 end

spec/controllers/api/exchange_products_controller_spec.rb

@@ -17,7 +17,7 @@ module Api
           exchange = order_cycle.exchanges.incoming.first
           spree_get :index, exchange_id: exchange.id
 
-          expect(json_response.first["supplier_name"]).to eq exchange.variants.first.product.supplier.name
+          expect(json_response["products"].first["supplier_name"]).to eq exchange.variants.first.product.supplier.name
         end
       end
 
@@ -27,8 +27,8 @@ module Api
           spree_get :index, exchange_id: exchange.id
 
           suppliers = [exchange.variants[0].product.supplier.name, exchange.variants[1].product.supplier.name]
-          expect(suppliers).to include json_response.first["supplier_name"]
-          expect(suppliers).to include json_response.second["supplier_name"]
+          expect(suppliers).to include json_response["products"].first["supplier_name"]
+          expect(suppliers).to include json_response["products"].second["supplier_name"]
         end
       end
     end