require 'rss/0.9'

require 'glue/string'
require 'nitro/builder/xml'

module Nitro

# Build RSS represenations of ruby object collections.
# Utilize duck typing to grab the attributes to render.
# Add this mixin to you classes to support RSS rendering.
#
#--
# TODO: add more options here, 1.0/2.0 support and more.
# use custom version to add headers like the following.
# <?xml version="1.0" encoding="UTF-8"?>
# <?xml-stylesheet href="rss.css" type="text/css"?>
#++

module RssBuilderMixin
	include XmlBuilderMixin

	# === Options
	#
	# [+:description+]
	#		Description of the Feed
	# [+:base+]
	#		Base url of the Feed.
	# [+:link+]
	#		Link of the Feed.
	
	def build_rss_09(objects, options = {})
		c = {
			:description => 'Syndication'
		}.update(options)

		c[:base] ||= c[:link]

		raise "Option ':base' cannot be infered!" unless c[:base] 
	
		channel = RSS::Rss::Channel.new
		channel.description = c[:description]
		channel.link = c[:link] if c[:link] 
		
		for obj in objects
			item = RSS::Rss::Channel::Item.new
			item.title = obj.title if obj.respond_to?(:title)
			item.description = Glue::StringUtils.head(obj.body, 256) if obj.respond_to?(:body)
			item.link = "#{c[:base]}/#{obj.view_uri}" if obj.respond_to?(:view_uri)
			channel.items << item
		end
		
		rss = RSS::Rss.new '0.9'
		rss.channel = channel
		
		self << rss.to_s
	end
	alias_method :build_rss, :build_rss_09

=begin
	Experimental.
	
	def build_rss(objects, options = {})
		# pi! :xml, :version => '1.0', :encoding => 'UTF-8'
		self << '<?xml version="1.0" encoding="UTF-8" ?>'
		self <<	'<?xml-stylesheet href="rss.css" type="text/css" ?>'
		rss(:version => '2.0', 
				'xmlns:dc' => 'http://purl.org/dc/elements/1.1/', 
				'xmlns:trackback' => 'http://madskills.com/public/xml/rss/module/trackback/') {
			channel {
				title 'koko' 
				language 'en-us'
				ttl '40'
				description 'hello lamer'

				for obj in objects
					item {
						title(obj.title)
						description(obj.body)
						trackback :ping => 'http://www.joy.gr'
					}
				end
			}
		}
	end
=end

end

# Abstract class for the RssBuilderMixin.

class RssBuilder < String
	include RssBuilderMixin

	class << self
		def build_09(objects, options = {})
			RssBuilder.new.build_rss_09(objects, options)
		end
	  alias_method :build, :build_09
	end
end

end

# * George Moschovitis <gm@navel.gr>