1 files changed, 48 insertions, 0 deletions
diff --git a/lib/gitlab/analytics/cycle_analytics/average.rb b/lib/gitlab/analytics/cycle_analytics/average.rb
new file mode 100644
index 00000000000..a449b71b165
--- /dev/null
+++ b/lib/gitlab/analytics/cycle_analytics/average.rb
@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Analytics
+    module CycleAnalytics
+      class Average
+        include Gitlab::Utils::StrongMemoize
+        include StageQueryHelpers
+
+        def initialize(stage:, query:)
+          @stage = stage
+          @query = query
+        end
+
+        def seconds
+          select_average ? select_average['average'] : nil
+        end
+
+        def days
+          seconds ? seconds.fdiv(1.day) : nil
+        end
+
+        private
+
+        attr_reader :stage
+
+        # rubocop: disable CodeReuse/ActiveRecord
+        def select_average
+          strong_memoize(:select_average) do
+            execute_query(@query.select(average_in_seconds.as('average')).reorder(nil)).first
+          end
+        end
+        # rubocop: enable CodeReuse/ActiveRecord
+
+        def average
+          Arel::Nodes::NamedFunction.new(
+            'AVG',
+            [duration]
+          )
+        end
+
+        def average_in_seconds
+          Arel::Nodes::Extract.new(average, :epoch)
+        end
+      end
+    end
+  end
+end