Add the "Plan" Cycle Analytics query.

1. Move from raw SQL to ActiveRecord.
2. Add a non-persisted `CycleAnalytics` model to store all the queries.

1 files changed, 40 insertions, 0 deletions

diff --git a/app/models/cycle_analytics.rb b/app/models/cycle_analytics.rb
new file mode 100644
index 00000000000..d037b1fef12
--- /dev/null
+++ b/app/models/cycle_analytics.rb
@@ -0,0 +1,40 @@
+class CycleAnalytics
+  def issue
+    issues = Issue.includes(:metrics).where("issue_metrics.id IS NOT NULL").references(:issue_metrics).to_a
+    start_time_fn = -> (issue) { issue.created_at  }
+    end_time_fn = -> (issue) { issue.metrics.first_associated_with_milestone_at.presence || issue.metrics.first_added_to_board_at.presence }
+
+    calculate_metric(issues, start_time_fn, end_time_fn)
+  end
+
+  def plan
+    issues = Issue.includes(:metrics).where("issue_metrics.id IS NOT NULL").references(:issue_metrics).to_a
+    start_time_fn = -> (issue) { issue.metrics.first_associated_with_milestone_at.presence || issue.metrics.first_added_to_board_at.presence }
+    end_time_fn = lambda do |issue|
+      merge_requests = issue.closed_by_merge_requests
+      merge_requests.map(&:created_at).min if merge_requests.present?
+    end
+
+    calculate_metric(issues, start_time_fn, end_time_fn)
+  end
+
+  private
+
+  def calculate_metric(data, start_time_fn, end_time_fn)
+    times = data.map do |data_point|
+      start_time = start_time_fn[data_point]
+      end_time = end_time_fn[data_point]
+
+      if start_time.present? && end_time.present?
+        end_time - start_time
+      end
+    end
+
+    median(times.compact)
+  end
+
+  def median(coll)
+    size = coll.length
+    (coll[size / 2] + coll[(size - 1) / 2]) / 2.0
+  end
+end