1 files changed, 54 insertions, 0 deletions
diff --git a/app/services/members/invitation_reminder_email_service.rb b/app/services/members/invitation_reminder_email_service.rb
new file mode 100644
index 00000000000..e589cdc2fa3
--- /dev/null
+++ b/app/services/members/invitation_reminder_email_service.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+module Members
+  class InvitationReminderEmailService
+    include Gitlab::Utils::StrongMemoize
+
+    attr_reader :invitation
+
+    MAX_INVITATION_LIFESPAN = 14.0
+    REMINDER_RATIO = [2, 5, 10].freeze
+
+    def initialize(invitation)
+      @invitation = invitation
+    end
+
+    def execute
+      return unless experiment_enabled?
+
+      reminder_index = days_on_which_to_send_reminders.index(days_after_invitation_sent)
+      return unless reminder_index
+
+      invitation.send_invitation_reminder(reminder_index)
+    end
+
+    private
+
+    def experiment_enabled?
+      Gitlab::Experimentation.enabled_for_attribute?(:invitation_reminders, invitation.invite_email)
+    end
+
+    def days_after_invitation_sent
+      (Date.today - invitation.created_at.to_date).to_i
+    end
+
+    def days_on_which_to_send_reminders
+      # Don't send any reminders if the invitation has expired or expires today
+      return [] if invitation.expires_at && invitation.expires_at <= Date.today
+
+      # Calculate the number of days on which to send reminders based on the MAX_INVITATION_LIFESPAN and the REMINDER_RATIO
+      REMINDER_RATIO.map { |number_of_days| ((number_of_days * invitation_lifespan_in_days) / MAX_INVITATION_LIFESPAN).ceil }.uniq
+    end
+
+    def invitation_lifespan_in_days
+      # When the invitation lifespan is more than 14 days or does not expire, send the reminders within 14 days
+      strong_memoize(:invitation_lifespan_in_days) do
+        if invitation.expires_at
+          [(invitation.expires_at - invitation.created_at.to_date).to_i, MAX_INVITATION_LIFESPAN].min
+        else
+          MAX_INVITATION_LIFESPAN
+        end
+      end
+    end
+  end
+end