give files index based on order in a table of content file

give_index.rb

# quick script to give files an index calculated from a table of contents file
class Renamer
  COMMON_STRING = 'Series Name by Author Name'
  def run
    actual.content.each do |file|
      clean_file = file.gsub(COMMON_STRING, '')
      to         = wished.wished_file_for_file(clean_file)
      cmd        = "mv '#{file}' #{to}"
      puts cmd
      `#{cmd}`
    end
  end

  def actual
    @actual ||= ActualContent.new
  end

  def wished
    @wished ||= WishedContent.new
  end
end

class ActualContent
  def content
    @content ||= Dir['*.flv']
  end
end

class Ranker
  COMMON_WORDS = %w(
    and
    with
    on
    flv
    a
  )

  def self.similarity(w1, w2)
    words1 = words_from_string(w1)
    words2 = words_from_string(w2)
    res    = (words1 & words2).size
    res
  end

  def self.words_from_string(str)
    all = str.split(/[-\s\.]/).map{|x|
      a = x.gsub(/[^\w-]/, '')
      a = a.downcase
      a = nil if a == ''
      a
    }.compact.uniq.sort
    (all - COMMON_WORDS)
  end
end

class WishedContent
  # @public
  def wished_file_for_file(file)
    wished_files.sort_by do |wished_file|
      -Ranker.similarity(file, wished_file)
    end.first
  end

  def lines
    @lines ||= File.read('Table of Contents.txt').split("\n")
  end

  def wished_files
    @wished_files ||= lines.each_with_index.map do |el, i|
      el = el.strip
      filename_with_index(el, i) if i % 2 == 0
    end.compact
  end

  def filename_with_index(file, index)
    file_index = ((index + 1) / 2) + 1
    clean_name = to_url(file.strip)
    file_name  = file_index.to_s.rjust(2, '0') + '-' + clean_name + ".flv"
  end

  def to_url(str)
    str.downcase.strip.gsub(' ', '-').gsub('&', 'and').gsub(/[^\w-]/, '')
  end
end

Renamer.new.run