#!/usr/bin/env ruby

require "amazon/search"
require "rubygems"
require "id3lib"
require "tmpdir"
require "find"
require "net/http"

@covercache = Hash.new


def get_cover(artist, title)
  if @covercache.has_key?(title + artist) then
    return @covercache[title + artist]
  end
  puts "searching #{artist} - #{title}"
  dir = Dir::tmpdir + "/"
  begin
    req = Amazon::Search::Request.new "" 
    res = req.keyword_search(artist + " " + title, 'music')
    if !res.products[0].image_url_medium.nil?
      url = res.products[0].image_url_medium
    elsif !res.products[0].image_url_small.nil?
      url = res.products[0].image_url_small
    end
    if url.nil? then
      return nil
    end
    urlparts = url.split("/")
    if !File.exist?(dir + urlparts[5])
      Net::HTTP.start(urlparts[2]) do |http|
        resp = http.get("/"+urlparts[3..5].join("/"))
        open(dir + urlparts[5], "wb") do |file|
          file.write(resp.body)
        end
      end
    end
  rescue
    STDERR.puts "no match found for query"
    return nil
  end
  @covercache[title + artist] = dir + urlparts[5]
  return dir + urlparts[5]
end

def insert_cover(tag, file)
puts "inserting #{file}"
  cover = {
     :id          => :APIC,
     :mimetype    => 'image/jpeg',
     :picturetype => 3,
     :description => "Album cover for #{tag.artist} - #{tag.title}",
     :textenc     => 0,
     :data        => File.read(file)
   }
   tag << cover
   tag.update!
end

def traverse_music(root)
  Find.find(root) do |path|
     filetype = File.basename(path.downcase).split(".").last
     if ['mp3'].include?(filetype) then
       yield path
     end
  end
end

covertmps = []
traverse_music(ARGV[0]) do |file|
  tag = ID3Lib::Tag.new(file)
  if tag.artist.nil? or tag.album.nil? then
    next
  end
  if tag.frame(:APIC).nil?
    coverfile = get_cover(tag.artist, tag.album)
    if !coverfile.nil?
      covertmps.push(coverfile)
      insert_cover(tag, coverfile)
    end
  else
    puts "#{file} already has a cover attached!"
  end
end
#covertmps.collect{|file| File.unlink(file)}