class Subdomain class self def instance _instance self new end def met

class Subdomain
  class << self
    def instance
      @_instance ||= self.new
    end

    def method_missing(meth, *args, &block)
      if [:match, :domain, :domain=].include? meth
        instance.send meth, *args
      else
        super
      end
    end
  end

  attr_accessor :domain

  def match(subdomain)
    if !subdomain
      cast_subdomain nil
    else
      {subdomain: cast_subdomain(subdomain)}
    end
  end

  private
  def cast_subdomain(subdomain)
    if domain.nil?
      subdomain
    else
      '' << subdomain << '.' << domain.split('.')[0..-3].join('.')
    end
  end
end