#! /usr/bin/env ruby

require 'rubygems'
require 'fileutils'
require 'mechanize'
require 'logger'
require 'ostruct'
require 'open-uri'

require 'optparse'

class MuxRip
  
  LOG = Logger.new STDOUT
  LOG.level = Logger::INFO
  
  class << self

    def log_level(lvl)
      LOG.level = lvl
    end

    # Download the HTML files for a set of Muxtapes
    def grab(names)
      new_mixtapes = {}
      agent = WWW::Mechanize.new
      names.each do |name|
        link = "http://" + name + ".muxtape.com"
        file_name = Tempfile.new(name).path
        new_mixtapes[name] = file_name
        LOG.info "Downloading #{name}..."
        agent.get(link).save_as(file_name)
      end
      new_mixtapes
    end

    # Scrape the Muxtape pages for track names and URLs
    def analyze(mixtapes)
      mixtape_songs = {}
      mixtapes.each do |name,file_name|
        LOG.info("Analyzing #{name}...")
        page = Hpricot(open(file_name))

        # Find script that passes "Kettle" the necessary Amazon keys
        # and scrape the song id/key pairs. These aren't necessarily
        # in playlist order.
        code_map = {}
        (page/"script").each do |script|
          src = script.inner_text
          if src =~ /new\s+Kettle\(\[([^\]]+)\],\[([^\]]+)\]/
            ids, codes = [$1, $2].map {|a| a.gsub("'",'').split(",") }
            ids.zip(codes).each do |ic|
              code_map["#{ic[0]}"] = ic[1]
            end
          end
        end

        # Now walk the playlist, scrape the names, and build the URLs
        songs = []
        (page/"li.song").each do |li|
          id = li.get_attribute('id').sub(/^song/,'')
          code = code_map[id]
          song = (li/'div.name').inner_text.strip
          LOG.debug("#{id}, #{code}, '#{song}'")
          songs << OpenStruct.new(:name => "#{song}", 
                                  :url => "http://muxtape.s3.amazonaws.com/songs/#{id}?#{code}")
        end

        mixtape_songs[name] = songs
      end
      mixtape_songs
    end

    # Download Muxtape MP3s
    def download(mixtapes)
      mixtape_songs = {}
      mixtapes.each do |mixtape, songs|
        LOG.info("Downloading songs for #{mixtape}...")
        FileUtils.mkdir_p("#{mixtape}")
        dl_songs = []
        songs.each do |song| 
          num_tries = 3
          begin
            song_file =  "#{mixtape}/#{song.name}.mp3"
            LOG.info("Downloading #{song.name}...")
            LOG.debug("Retrieving #{song.url}")
            open(song.url) do |f| 
              open(song_file,"wb") {|mp3| mp3.write f.read }
            end
            dl_songs << song
          rescue
            num_tries -= 1
            LOG.info("Error downloading: #{num_tries} left")
            next if num_tries == 0
            retry
          end
        end
        mixtape_songs[mixtape] = dl_songs
      end
      mixtape_songs
    end

    # Dump a Muxtape to M3U format
    def m3u(mixtapes)
      mixtapes.each do |mixtape,songs|
        m3u_file = "#{mixtape}/#{mixtape}.m3u"
        LOG.info("Creating playlist #{m3u_file}...")
        output = File.open(m3u_file,"w+")
        output.write("#EXTM3U\n")
        songs.each do |song| 
          output.write("#EXTINF:-1,#{song.name}\n#{song.name}.mp3\n")
        end
        output.close
      end
    end

    # Import a Muxtape into iTunes
    def itunes(mixtapes)
      LOG.info("Launching iTunes...")
      i_tunes = app('iTunes')
      mixtapes.each do |mixtape,songs|
        next if i_tunes.playlists[its.name.eq(mixtape)].exists #skip if exists
        LOG.info("Creating playlist #{mixtape}...")
        pl = i_tunes.make(:new => :user_playlist, :with_properties => {:name => mixtape})
        LOG.info("Adding files...")
        songs.each do |song| 
          i_tunes.add(MacTypes::FileURL.path(File.expand_path(File.dirname(__FILE__) + "/#{mixtape}/#{song.name}.mp3")),  :to => pl) 
        end
      end
    end
  end
end

options = { :m3u => true, :itunes => false }

name = File.basename($0, '.*')
parser = OptionParser.new("Usage: #{$0} [options] MUXTAPE [MUXTAPE ...]")
parser.on('-h', '--help',
  'display usage information') do
  puts parser
  exit
end
parser.on('-q', '--quiet', 'suppress normal output') do
  MuxRip.log_level( Logger::WARN )
end
parser.on('--nom3u',
          'do not create an M3U playlist') do
  options[:m3u] = false
end
parser.on('--itunes',
          'import Muxtape to iTunes') do
  options[:itunes] = true
end

# Unmatched command-line arguments should be Muxtape names
mixtapes = parser.parse($*)
results = MuxRip.download( MuxRip.analyze( MuxRip.grab(mixtapes) ) )

if options[:m3u]
  MuxRip.m3u( results )
end

if options[:itunes]
  require "appscript"
  include Appscript
  MuxRip.itunes( results )
end