Copies songs from m3u playlist to another directory

playlist_copier.rb

#!/bin/ruby
require 'xmlsimple'
require 'fileutils'
require 'optparse'

DEST="/Volumes/TB/NewMusic/"

options = {
  destination: DEST,
  dry_run: false
}

OptionParser.new do |opts|
  opts.banner = "Usage: #{$0} [m3u file]"

  opts.on("-t", "--dry-run", "Dry Run") do
    options[:dry_run] = true
  end

  opts.on("-d", "--dest", "Destination") do |d|
    options[:destination] = d
  end
end.parse

m3u_file=ARGV.last

raise "files not found: #{m3u_file}" unless File.exists?(m3u_file)
raise "directory does not exists" unless Dir.exists?(options[:destination])

class M3UCopier
  attr_accessor :m3u_file, :destination, :dry_run
  attr_accessor :options

  def initialize(m3u_file, options)
    self.m3u_file = m3u_file
    self.destination = options[:destination]
    self.dry_run = options[:dry_run] || false

    self.options = options
  end

  def copy_songs!
    lines = File.read(m3u_file).split("\r")
    songs = lines.reject{|p| p.match /^#EXT/ }
    source_dir = find_common_dir(songs)

    songs.each do |song|
      puts "Looking at #{song}"
      new_directory = File.dirname(song).gsub(Regexp.new("^#{source_dir}"), destination)
      unless Dir.exists?(new_directory)
        puts "\tCreating directory #{new_directory}"
        FileUtils.mkdir_p(new_directory) unless dry_run
      end
      new_path = song.gsub(Regexp.new("^#{source_dir}"), destination)
      unless File.exists?(new_path)
        puts "\tcopying to #{new_path}"
        FileUtils.cp(song, new_path) unless dry_run
      else
        puts "\tfile already exists: #{new_path}"
      end
    end
  end

  def find_common_dir(dirs)
    shared_dir = File.dirname(dirs.first)

    dirs.each_with_index do |dir, idx|
      shared_dir = find_common_string(shared_dir, dir)
    end

    shared_dir
  end


  def find_common_string(dir1, dir2)
    str1 = dir1.split('')
    str2 = dir2.split('')

    common_chars = -1
    str1.each_with_index do |char, idx|
      if char == str2[idx]
        common_chars = idx
      else
        break
      end
    end

    if common_chars >= 0
      dir1[0..common_chars]
    end
  end
end

M3UCopier.new(m3u_file, options).copy_songs!