module SingleTableInheritance

  def self.included(klass)
    klass.extend ClassMethods
  end

  def class_type=(value)
    self[:type] = value
  end

  def class_type
    return self[:type]
  end

  def after_initialize
    self.class_type = self.name if self.class_type.nil?
  end

  module ClassMethods
    def factory(params = {})
      class_name = params[:type]
      class_name ||= self.name
      if defined? class_name.constantize
        o = class_name.constantize.new(params)
      else
        o = self.new(params)
      end
      o.class_type = class_name if o.class_type.nil?
      o
    end

    def factory!(params = {})
      o = factory params
      o.save!
      o
    end

    def call_class_method(class_name, method_name, *args)
      class_name ||= self.name
      if defined? class_name.constantize
        class_name.constantize.method(method_name).call(*args)
      else
        self.method(method_name).call(*args)
      end
    end
  end
end