class Comment
  include Mongoid::Document
  include Mongoid::Timestamps

  after_create :increase_counter_cache
  before_destroy :decrease_counter_cache

  after_create :deliver_email, if: :emailable?

  field :body, type: String
  index(user_id: 1)

  belongs_to :err, class_name: "Problem"
  belongs_to :user

  delegate :app, to: :err

  validates :body, presence: true

  def deliver_email
    Mailer.comment_notification(self).deliver_now
  end

  def notification_recipients
    app.notification_recipients - [user.email]
  end

  def emailable?
    app.emailable? && notification_recipients.any?
  end

protected

  def increase_counter_cache
    err.inc(comments_count: 1)
  end

  def decrease_counter_cache
    err.inc(comments_count: -1) if err
  end
end
