jpmckinney/multi_mail

module MultiMail
  # Interacts with email APIs to send or receive email.
  #
  # @see http://rdoc.info/gems/fog/Fog/Service
  module Service
    # Appends the given arguments to the list of required arguments.
    #
    # @param args one or more required arguments
    # @see Fog::Service::requires
    def requires(*args)
      requirements.concat(args)
    end

    # Returns the list of required arguments.
    #
    # @return [Array] a list of required arguments
    # @see Fog::Service::requirements
    def requirements
      @requirements ||= []
    end

    # Appends the given arguments to the list of optional arguments.
    #
    # @param args one or more optional arguments
    # @see Fog::Service::recognizes
    def recognizes(*args)
      recognized.concat(args)
    end

    # Returns the list of optional arguments.
    #
    # @return [Array] a list of optional arguments
    # @see Fog::Service::recognized
    def recognized
      @recognized ||= []
    end

    # Ensures that required arguments are present and that optional arguments
    # are recognized.
    #
    # @param [Hash] options arguments
    # @raise [ArgumentError] if it can't find a required argument or can't
    #   recognize an optional argument
    # @see Fog::Service::validate_options
    def validate_options(options, raise_error_if_unrecognized = true)
      keys = []
      for key, value in options
        unless value.nil?
          keys << key
        end
      end

      missing = requirements - keys
      unless missing.empty?
        raise ArgumentError, "Missing required arguments: #{missing.map(&:to_s).sort.join(', ')}"
      end

      if !recognizes.empty? && raise_error_if_unrecognized
        unrecognized = options.keys - requirements - recognized
        unless unrecognized.empty?
          raise ArgumentError, "Unrecognized arguments: #{unrecognized.map(&:to_s).sort.join(', ')}"
        end
      end
    end
  end
end