openxml/openxml-package

module OpenXml
  module Properties
    class BaseProperty
      attr_reader :value

      class << self
        attr_reader :property_name
        attr_reader :allowed_tags

        def tag_is_one_of(tags)
          attr_accessor :tag
          @allowed_tags = tags
        end

        def tag(*args)
          @tag = args.first if args.any?
          @tag ||= nil
        end

        def name(*args)
          @property_name = args.first if args.any?
          @property_name ||= nil
        end

        def namespace(*args)
          @namespace = args.first if args.any?
          @namespace ||= nil
        end

      end

      def initialize(tag=nil, *_args)
        return unless self.class.allowed_tags
        validate_tag tag
        @tag = tag
      end

      def validate_tag(tag)
        return if self.class.allowed_tags.include?(tag)
        allowed = self.class.allowed_tags.join(", ")
        raise ArgumentError, "Invalid tag name for #{name}: #{tag.inspect}. It should be one of #{allowed}."
      end

      def render?
        !value.nil?
      end

      def name
        self.class.property_name || default_name
      end

      def default_name
        class_name.gsub(/(.)([A-Z])/, '\1_\2').downcase
      end

      def tag
        self.class.tag || default_tag
      end

      def default_tag
        (class_name[0, 1].downcase + class_name[1..-1]).to_sym
      end

      def namespace
        self.class.namespace
      end

    private

      def apply_namespace(xml)
        namespace.nil? ? xml : xml[namespace]
      end

      def class_name
        self.class.to_s.split(/::/).last
      end

    end
  end
end