gistfile1.rb

module CalculateCountEvents
  extend ActiveSupport::Concern

  def count_new_events
    if self.has_role? :traveler
      count_discussions_events + count_applications_events
    else
      count_discussions_events + count_orders_events
    end
  end

  def count_orders_events
    count = 0
    self.orders.each do |order|
      unless order.is_viewed.present?
        count += 1
      else
        count += has_unviewed_histories_or_messages order
      end
    end
    count
  end

  def count_applications_events
    count = 0
    self.applications.each do |application|
      count += has_unviewed_histories_or_messages application
    end
    count
  end

  def count_discussions_events
    count = 0
    self.discussion_users.each do |discussion_user|
      discussion = discussion_user.discussion
      if discussion.discussion_messages.unviewed_for_user(self.id).size > 0
        count += 1
      end
    end
    count
  end

  def has_unviewed_histories_or_messages order
    if count_unviewed_order_status_histories(order) > 0
      1
    else
      if count_unviewed_order_messages(order) > 0
        1
      else
        0
      end
    end
  end

  def count_unviewed_order_status_histories order
    order.order_status_histories.unviewed_for_user(self.id).size
  end

  def count_unviewed_order_messages order
    order.order_messages.unviewed_for_user(self.id).size
  end
end

Пока без кэширования