gistfile1.rb

require 'rubygems'
require 'nokogiri'
require 'open-uri'

def main
  html = Nokogiri(open('http://www.last.fm/user/youpy/friends').read)
  next_link = nil
  tracks = []

  begin
    spans = html.search('//p[@class="nowListening"]/span')
    unless spans.empty?
      spans.each do |span|
        tracks << span.search('.//a').map {|e| e.text }
      end
    end

    next_link = html.at('//a[@class="nextlink"]')
  end while next_link && html = Nokogiri(open(URI('http://www.last.fm/') + URI(next_link[:href])).read)

  itunes = ITunes()
  unless itunes.playing?
    tracks.sort_by { rand }.each do |track|
      artist, name = track
      unless (found_tracks = itunes.search_track(name, artist)).empty?
        selected_track = found_tracks.sort_by {|track| track.duration }.last
        itunes.play(selected_track, :once => 1)
        break
      end
    end
  end
end

def ITunes
  case RUBY_PLATFORM
  when /darwin/
    ITunes::Mac.new
  when /win/
    ITunes::Windows.new
  else
    raise "not implemented yet"
  end
end

module ITunes
  class Mac
    def initialize

      require 'rbosa'
      OSA.utf8_strings = true
      @itunes = OSA.app('iTunes')
    end

    def playing?
      @itunes.player_state.to_s == 'playing'
    end

    def current_track
      {
        :name => @itunes.current_track.name,
        :artist => @itunes.current_track.artist,
        :rating => @itunes.current_track.rating
      }
    end

    def search_track(name, artist)
      library.playlists[0].search([name, artist].join(' '))
    end

    def play(track, options = {})
      @itunes.play(track, options)
    end

    private

    def library
      @itunes.sources.find {|s| s.kind == OSA::ITunes::ESRC::LIBRARY }
    end
  end

  class Windows
    def initialize
      require 'win32ole'
      @itunes = WIN32OLE.new("iTunes.Application")
    end

    def playing?
      @itunes.CurrentTrack
    end

    def current_track
      {
        :name => @itunes.CurrentTrack.Name,
        :artist => @itunes.CurrentTrack.Artist,
        :rating => @itunes.CurrentTrack.Rating
      }
    end

    def search_track(name, artist)
      @itunes.LibraryPlaylist.Search([name, artist].join(' '))
    end

    def play(track, options = {})
      raise "I don't know how to play selected track..."
    end
  end
end

main