added 260907 version of worker toolkit

worker-toolkit-flaredown/repo/backend/app/services/collection_retriever.rb

@@ -0,0 +1,60 @@
+class CollectionRetriever
+  attr_reader :occurrences
+
+  def initialize(model, scope, current_user = nil)
+    # FIXME
+    # rubocop:disable Style/SignalException
+    fail ArgumentError unless [:most_popular, :most_recent].include?(scope)
+    # rubocop:enable Style/SignalException
+
+    @model = model
+    @scope = scope
+    @ids_key = "#{model.name.underscore}_ids"
+    @ids_field = "$#{@ids_key}"
+    @current_user = current_user
+  end
+
+  def retrieve
+    send @scope
+  end
+
+  private
+
+  def most_popular
+    @occurrences = Checkin.collection.aggregate(
+      [
+        # Step 1: have one entry per object id
+        {"$unwind" => @ids_field},
+        # Step 2: group by object id and count occurrences
+        {"$group" => {_id: @ids_field, count: {"$sum" => 1}}},
+        # Step 3: sort by occurrences, descending
+        {"$sort" => {count: -1}},
+        # Step 4: limit to 10 results
+        {"$limit" => 10}
+      ]
+    )
+
+    @model.where(id: occurrences.map { |o| o["_id"] }, global: true)
+  end
+
+  def most_recent
+    checkin_relations = Checkin.collection.aggregate(
+      [
+        # Step 1: filter by user
+        {"$match" => {encrypted_user_id: @current_user.encrypted_id}},
+        # Step 2: have one entry per object id
+        {"$unwind" => @ids_field},
+        # Step 3: sort by checkin date, descending
+        {"$sort" => {date: -1}},
+        # Step 4: limit to 10 results
+        {"$limit" => 10}
+      ]
+    )
+
+    @model.accessible_by(current_ability).where(id: checkin_relations.map { |o| o[@ids_key] })
+  end
+
+  def current_ability
+    Ability.new(@current_user)
+  end
+end