notifiable.rb

module Notifiable
  extend ActiveSupport::Concern

  # def notification_mailer_class
  #   Implement this method
  # end

  def notified?
    !notified_at.nil?
  end

  def notifiable?
    !notified? && author.present?
  end

  def notify_participants!
    notify course.active_participants
  end

  def notify_students!
    notify course.active_students
  end

  def notified!
    update notified_at: Time.now
  end

  private

  def notify(scope)
    return false unless notifiable?
    scope.
      where.not(users: {id: author.id}).
      merge(Enrollment.wants_email_notifications).
      each { |u| notification_mailer_class.notification(self, u).deliver_later }
    notified!
  end

end