Merge pull request #1120 from transitland/stop-min-platforms

Stop: min platforms query

app/controllers/api/v1/stop_stations_controller.rb

@@ -22,6 +22,9 @@ def index_query
     if params[:wheelchair_boarding].present?
       @collection = @collection.where(wheelchair_boarding: AllowFiltering.to_boolean(params[:wheelchair_boarding] ))
     end
+    if params[:min_platforms].present?
+      @collection = @collection.with_min_platforms(params[:min_platforms].to_i)
+    end
   end
 
   def index_includes
@@ -92,6 +95,10 @@ def query_params
       wheelchair_boarding: {
         desc: "Wheelchair boarding",
         type: "boolean"
+      },
+      min_platforms: {
+        desc: "Mininum number of platforms",
+        type: "integer"
       }
     })
   end

app/controllers/concerns/json_collection_pagination.rb

@@ -41,7 +41,9 @@ def paginated_collection(collection)
     end
 
     if include_total
-      meta[:total] = collection.count
+      total = collection.count
+      (total = total.size) if total.is_a?(Hash)
+      meta[:total] = total
     end
     # Return results + meta
     data_on_page = data_on_page.empty? ? collection.model.none : data_on_page

app/models/stop.rb

@@ -238,6 +238,13 @@ def parent_stop
     where('last_conflated_at <= ?', last_conflated_at)
   }
 
+  scope :with_min_platforms, -> (min_platform_count) {
+    where(type: nil)
+    .joins("INNER JOIN current_stops AS current_stop_platforms ON current_stop_platforms.type = 'StopPlatform' AND current_stop_platforms.parent_stop_id = current_stops.id")
+    .group('current_stops.id, current_stop_platforms.parent_stop_id')
+    .having('COUNT(current_stop_platforms.id) >= ?', min_platform_count || 1)
+  }
+
   def coordinates
     g = geometry(as: :wkt)
     [g.lon, g.lat]

config/initializers/squeel.rb

@@ -11,3 +11,21 @@ def within *list
     end
   end
 end
+
+# WARNING: a monkey patch from
+# https://stackoverflow.com/questions/31860441/deprecation-warning-modifying-already-cached-relation-on-postgres-max-greates
+# to handle:
+#   DEPRECATION WARNING: Modifying already cached Relation. The cache will be reset.
+module Squeel
+  module Adapters
+    module ActiveRecord
+      module RelationExtensions
+
+        def execute_grouped_calculation(operation, column_name, distinct)
+          super
+        end
+
+      end
+    end
+  end
+end

spec/models/stop_spec.rb

@@ -163,6 +163,30 @@
     end
   end
 
+  context '.with_min_platforms' do
+    before(:each) do
+      @s1 = create(:stop)
+      @s2 = create(:stop)
+      @s2p1 = create(:stop_platform, parent_stop: @s2)
+      @s3 = create(:stop)
+      @s3p1 = create(:stop_platform, parent_stop: @s3)
+      @s3p2 = create(:stop_platform, parent_stop: @s3)
+    end
+
+    it 'returns only Stops with StopPlatforms' do
+      expect(Stop.with_min_platforms(1)).to match_array([@s2, @s3])
+    end
+
+    it 'returns minimum StopPlatforms' do
+      expect(Stop.with_min_platforms(2)).to match_array([@s3])
+    end
+
+    it 'works with count' do
+      # Handled in JSON pagination concern
+      expect(Stop.with_min_platforms(1).count.size).to eq(2)
+    end
+  end
+
   context 'served_by' do
     before(:each) do
       @bart = create(:operator, name: 'BART')