require "rss/maker"
require "open-uri"
require "hpricot"

class Feedalizer
  VERSION = "0.1.2" # UNRELEASED
  IDENTIFIER = "Feedalizer/#{VERSION} (http://termos.vemod.net/feedalizer)"
  
  attr_reader :page

  def initialize(url, &block)
    @page = grab_page(url)
    @rss = RSS::Maker::RSS20.new

    feed.generator = IDENTIFIER
    feed.link = url
    feed.description = "Scraped from #{url}"

    instance_eval(&block) if block
  end

  def feed
    @rss.channel
  end

  def scrape_items(hpricot_query, limit = 15)
    elements = @page.search(hpricot_query)
    
    elements.first(limit).each do |html_element|
      rss_item = @rss.items.new_item
      yield rss_item, html_element
    end
  end

  def grab_page(url)
    open(url) { |io| Hpricot(io) }
  end

  def output
    if @rss.respond_to?(:to_feed) # Ruby >= 1.8.7
      @rss.to_feed.to_s
    else
      @rss.to_rss.to_s
    end
  end

  def output!(target = STDOUT)
    target << output
  end

  def debug!
    @rss.items.each do |item|
      STDERR.puts [ item.title, item.date, item.link ].join("; ")
    end
  end
  
  # Backwards-compatibility
  alias_method :parse_source, :grab_page
  alias_method :source, :page
end

# A handy wrapper for Feedalizer.new :-)
def feedalize(*args, &block)
  Feedalizer.new(*args, &block)
end