Renaming script I use for managing episodes of downloaded series batches

renamer.rb

#!/usr/bin/env ruby

require "fileutils"
require "highline"

# Characters illegal in most filenames
ILLEGAL_CHARS = %w[< > : " / \\ | * ?]

cli = HighLine.new

files = ARGV.select {|f| File.file? f }.freeze
files.each do |f|
  next if File.basename(f) == f
  warn "'#{f}' is not the same as its basename, aborting. (Not in current directory?)"
  exit 1
end

puts HighLine.color("Processing #{files.size} files", :green)

# Set the prefix, typically the show name
prefix = cli.ask("Prefix (show name)? ") do |q|
  q.validate = lambda do |a|
    a.match?(/\A[[:print:]]+\z/) && !a.match?(Regexp.union(ILLEGAL_CHARS))
  end

  q.readline = true

  q.responses[:not_valid] = "The prefix may not contain illegal characters (#{ILLEGAL_CHARS.join(", ")})"
end

# Get the season (or disable)
season = cli.ask("Season (Leave empty for no season)? ") do |q|
  q.validate = -> (a) { a == "" || a.to_i > 0 }
  q.readline = true
  q.answer_type = -> (a) { a == "" ? nil : Integer(a, 10) }
  q.responses[:not_valid] = "You must enter a positive integer (> 0) or leave this empty."
end

puts "-------\n\n"

new_filenames = files.map do |f|
  puts "Processing file: '#{HighLine.color(f, :bold)}'"

  guessed_id = f.match(/S?\d+E(\d+)/i) {|m| Integer(m[1], 10) rescue nil } ||
                  f.match(/(\d\d)/) {|m| Integer(m[1], 10) rescue nil }

  episode_id = cli.ask("   Episode ID? ") do |q|
    # Either single digit (will be padded), double digit, or double-episode with
    # two double-digits joined by a &. Supports decimals.
    q.validate = /\A\d(?:\.\d)?\z|\A\d\d(?:\.\d)?(?:&\d\d(?:\.\d)?)?\z/

    q.default = format "%02d", guessed_id

    q.readline = true

    q.answer_type = lambda do |a|
      # Prefix the answer with a 0 if it was given as a single
      return a unless a.match?(/\A\d(?:\.\d)?\z/)
      "0" + a
    end

    q.responses[:not_valid] = "The episode ID must be in single digit form (D or D.D+), double digit form (DD or DD.D+), or double-double digit form (for double episodes, DD&DD DD.D+&DD.D+). Decimals are optional."
  end

  episode_title = cli.ask("Episode title? ") do |q|
    q.validate = lambda do |a|
      a.match?(/\A[[:print:]]+\z/) && !a.match?(Regexp.union(ILLEGAL_CHARS))
    end

    q.readline = true

    q.responses[:not_valid] = "The title may not contain illegal characters (#{ILLEGAL_CHARS.join(", ")})"
  end

  puts "-------\n\n" # Separator

  extension = f[/.*\.(.+?)\z/, 1] # File extension

  if season
    format "%s - S%02dE%s - %s.%s", prefix, season, episode_id, episode_title, extension
  else
    format "%s - %s - %s.%s", prefix, episode_id, episode_title, extension
  end
end

changes = files.zip new_filenames

left = [files.map(&:length).max + 1, 10].max
right = [new_filenames.map(&:length).max + 1, 5].max

puts HighLine.color(" Original ".ljust(left), :bold) + "|" + HighLine.color(" New", :bold)
puts "-" * left + "+" + "-" * right
puts changes.map {|old, new| old.rjust(left-1) + " → " + new }.join "\n"

puts HighLine.color(" → #{changes.select {|new, old| old != new }.size} changes.", :bold, :white)

apply = cli.agree(" Apply these changes? [y/n] ") do |q|
  q.character = :getc
end
puts # getc doesn't do a proper newline

if apply
  changes.each {|from, to| FileUtils.mv from, to }
  puts "done."
else
  puts "Not applying; exiting"
end