# Last.fm Tagger v0.7
#
# Author:
# wes@633k.net
#
# Abstract:
# For each selected track in iTunes, retrieve the genre from Last.fm and accordingly tag the track.
# Use -q to subdue confirmations
#
# Todo:
# Option to tag artist if no tag exists in last.fm records
# Retrieve all tags above <count>50</count>, prompt for tag choice

begin require 'rubygems'; rescue LoadError; end
%W{rbosa cgi rexml/document}.map { |i| require i }

OSA.utf8_strings = true

class Artist
  attr_reader :name, :genre
  
  def initialize(name='', genre='')
    @name, @genre = name, genre
    query unless name == ''
  end
  
  def query
    puts %{Querying last.fm for: "#{@name}"...}
    begin
      doc = REXML::Document.new(Net::HTTP.get(URI("http://ws.audioscrobbler.com/1.0/artist/#{URI.escape(CGI.escape(@name))}/toptags.xml")))
    rescue EOFError => e
      puts "#{Color.error} Request timed out! Trying again..."
      query
    end
    
    genre = REXML::XPath.first(doc, "//toptags/tag/name")
    genre.nil? ? @genre = "" : @genre = genre.text.strip
    @name = name.strip
  end
end

class LastfmTagger
  @@tagged, @@skipped = 0, 0

  def initialize
    itunes = OSA.app('iTunes')
    @selection = itunes.selection.get

    if @selection.empty?
      $stderr.puts "#{Color.error} Please select some tracks in iTunes"
    else
      # construct pseudo Artist to satify @selection loop
      @artist = Artist.new
    end
  end

  def process
    @selection.each do |track|
      # check if artist differs; if so, reinstantiate @artist
      if @artist.name.downcase != track.artist.strip.downcase
        @artist = Artist.new(track.artist)
        # no need to write tag if it is identical, therefore skip until it differs
        if track.genre.strip.downcase == @artist.genre.downcase
          puts "#{Color.pass} Identical genres. Skipping..."
          @@skipped += 1
          @input = 'n'
        elsif @artist.genre == ""
          puts %{#{Color.pass} No tags found for "#{@artist.name}".}
          @@skipped += 1
          @input = 'n'
        else
          @input = confirm
        end
      end
      track.genre = @artist.genre if @input == 'y'
    end
    puts "Done. Tagged #{@@tagged} artists. Skipped #{@@skipped}."
  end
  
  def confirm
    print %{#{Color.success} Tagging "#{@artist.name}" as "#{@artist.genre}". }
    @@tagged += 1

    # add some space when in quiet mode
    if quiet?
      puts
      return 'y'
    end

    print %{Continue? (Y/N) }
    gets.chomp.downcase
  end

  # handles -q argument
  def quiet?
    return true if ARGV[0] == '-q'
  end
end

class Color
  def self.pass
    "[ \e[33mPASS\e[0m ]"
  end
  
  def self.success
    "[ \e[32mSUCCESS\e[0m ]"
  end
  
  def self.error
    "[ \e[31mERROR\e[0m ]"
  end
end

LastfmTagger.new.process