require 'active_support'

module NinjaModel
  module Identity
    extend ActiveSupport::Concern
    include ActiveModel::AttributeMethods

    included do
      class_inheritable_accessor :primary_key
      self.primary_key = :id
      undef_method(:id) if method_defined?(:id)
    end

    def to_param
      send(self.class.primary_key).to_s if persisted?
    end

    def to_key
      key = nil
      key = send(self.class.primary_key) if persisted?
      [key] if key
    end
  end
end