Rails i18n unused key scanner

i18n_unused_scanner.rb

require 'yaml'
require 'awesome_print'
require 'open3'

###### keys diff start

def flat_hash(hash , flag = [] , global = {})
  return global.update({flag=>hash}) unless hash.is_a?(Hash)
  hash.each do |key,rnd|
    flat_hash(rnd,flag+[key],global)
  end
  global
end

keys = {tw:'zh-tw',cn:'zh-CN',en:'en'}

all_keys = keys.keys.map{|key|[key,{}]}.to_h

keys.each_pair do |key , file_name|
  keys[key] = flat_hash(YAML.load_file("#{__dir__}/../config/locales/#{file_name}.yml")[file_name]).keys.map{|i|i.join('::')}
end

keys.each_pair do |main_lang , main_keys| keys.each_pair do |sub_lang , sub_keys|
  next if main_lang == sub_lang
  (main_keys - sub_keys).each do |key|
    all_keys[main_lang][key] ||= []
    all_keys[main_lang][key] << sub_lang
  end
end end

all_keys.each_pair do |main_lang , sub_set| sub_set.each do |key , sub_langs|
  puts "(#{main_lang} - #{sub_langs.join(',')}) => #{key}"
end end

###### keys diff end

###### keys unused start

all_keys = {}
keys.each_value do |value_set| value_set.each do |value|
  all_keys[value.split('::').pop] = true
end end
all_keys = all_keys.keys

puts "start_search : #{all_keys.length} keys"

len = all_keys.length
flag = 0
flag_char = {0 => '-' , 1 => '\\' , 2 => '|' , 3 => '/'}
all_keys.each_with_index do |key , index|
  index += 1
  begin
    opts, errors, status = Open3.capture3(%Q%find #{__dir__}/../ -type f \\( -name "*.rb" -o -name "*.erb" \\) | xargs grep -m 1 "#{key}"%)
    if !errors.empty?
      puts "\r#{index}/#{len} : search_error1 : #{key}"
    elsif opts.empty?
      puts "\r#{index}/#{len} : maybe unused : #{key}"
    else
      flag = (flag + 1) % 4
      print "\r#{flag_char[flag]}"
    end
  rescue
    puts "\r#{index}/#{len} : search_error2 : #{key}"
  end
end

###### keys unused end

puts "[scan finished , please fix me ^.~]"