Add an `Issue::Metrics` model.

- And store the `first_associated_with_milestone_at` and
  `first_added_to_board_at` times, when an issue is saved.

2 files changed, 30 insertions, 0 deletions

diff --git a/app/models/issue.rb b/app/models/issue.rb
index 788611305fe..1aa0cef884e 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -23,6 +23,8 @@ class Issue < ActiveRecord::Base
 
   has_many :events, as: :target, dependent: :destroy
 
+  has_one :metrics, dependent: :destroy
+
   validates :project, presence: true
 
   scope :cared, ->(user) { where(assignee_id: user) }
@@ -36,6 +38,8 @@ class Issue < ActiveRecord::Base
   scope :order_due_date_asc, -> { reorder('issues.due_date IS NULL, issues.due_date ASC') }
   scope :order_due_date_desc, -> { reorder('issues.due_date IS NULL, issues.due_date DESC') }
 
+  after_save :record_metrics
+
   attr_spammable :title, spam_title: true
   attr_spammable :description, spam_description: true
 
@@ -270,4 +274,9 @@ class Issue < ActiveRecord::Base
   def check_for_spam?
     project.public?
   end
+
+  def record_metrics
+    metrics = Metrics.find_or_create_by(issue_id: self.id)
+    metrics.record!
+  end
 end
diff --git a/app/models/issue/metrics.rb b/app/models/issue/metrics.rb
new file mode 100644
index 00000000000..4436696cc1a
--- /dev/null
+++ b/app/models/issue/metrics.rb
@@ -0,0 +1,21 @@
+class Issue::Metrics < ActiveRecord::Base
+  belongs_to :issue
+
+  def record!
+    if issue.milestone_id.present? && self.first_associated_with_milestone_at.blank?
+      self.first_associated_with_milestone_at = Time.now
+    end
+
+    if issue_assigned_to_list_label? && self.first_added_to_board_at.blank?
+      self.first_added_to_board_at = Time.now
+    end
+
+    self.save if self.changed?
+  end
+
+  private
+
+  def issue_assigned_to_list_label?
+    issue.labels.any? { |label| label.lists.present? }
+  end
+end