module Rss20

  class Item < Element
    element :author, :email
    element :category, MANY
    element :comments, :rfc2396_full
    element :description, :safehtml
    element :enclosure
    element :guid, :unique
    element :link, REQUIRED
    element :pubDate, :rfc822
    element :source
    element :title, :nonhtml
  
    def end_element *args
      unless @children.include?('title') or @children.include?('description')
        log :ItemMustContainTitleOrDescription
      end
    end
  end

  class Cloud < Element
    def initialize parent
      super
      @valid = true
    end

    attribute :domain, REQUIRED
    attribute :path, REQUIRED
    attribute :port, :nonNegative
    attribute :protocol, REQUIRED, :nonNegative
    attribute :registerProcedure, REQUIRED

    def log *args
      @valid = false
      @parent.log *args
    end

    def end_element *args
      if @valid
        log :ValidCloud
      end
    end
  end

  class Channel < Element
    element :category, MANY
    element :cloud, Cloud
    element :copyright
    element :docs, :rfc2396
    element :description, REQUIRED
    element :generator
    element :image
    element :item, MANY, Item
    element :language, :iso639
    element :lastBuildDate, :rfc822
    element :link, REQUIRED
    element :managingEditor, :email
    element :pubDate, :rfc822
    element :skipDays, MANY
    element :skipHours, MANY
    element :textinput
    element :textInput
    element :title, REQUIRED, :nonhtml, :nonblank
    element :ttl, :positiveInteger, :nonblank
    element :webMaster, :email
  end
  
  class Rss < Element
    attribute :version, REQUIRED
    element :channel, REQUIRED, Channel
  end

end

class Root < Element
  element :rss, Rss20::Rss
  element :feed, :missing_namespace
end