namespace :locales do
  desc 'Updates language files based on en.yml content (only works for new top level keys).'
  task :update do
    dir = ENV['DIR'] || './config/locales'
    
    en_strings = YAML.load(File.read(File.join(dir,'en.yml')))['en']
    
    files = Dir.glob(File.join(dir,'*.{yaml,yml}'))
    files.each do |file|
      puts "Updating file #{file}"
      file_strings = YAML.load(File.read(file))
      file_strings = file_strings[file_strings.keys.first]
    
      missing_keys = en_strings.keys - file_strings.keys
      next if missing_keys.empty?
      
      puts "==> Missing #{missing_keys.size} keys (#{missing_keys.join(', ')})"
      lang = File.open(file, 'a')
      
      missing_keys.each do |key|
        {key => en_strings[key]}.to_yaml.each_line do |line|
          next if line =~ /^---/ || line.empty?
          puts "  #{line}"
          lang << "  #{line}"
        end
      end
      
      lang.close
    end
  end

  desc <<-END_DESC
Removes a translation string from all locale file (only works for top-level childless non-multiline keys, probably doesn\'t work on windows).

Options:
  key=key_1,key_2    Comma-separated list of keys to delete
  skip=en,de         Comma-separated list of locale files to ignore (filename without extension)
END_DESC

  task :remove_key do
    dir = ENV['DIR'] || './config/locales'
    files = Dir.glob(File.join(dir,'*.yml'))
    skips = ENV['skip'] ? Regexp.union(ENV['skip'].split(',')) : nil
    deletes = ENV['key'] ? Regexp.union(ENV['key'].split(',')) : nil
    # Ignore multiline keys (begin with | or >) and keys with children (nothing meaningful after :)
    delete_regex = /\A  #{deletes}: +[^\|>\s#].*\z/
    
    files.each do |path|
      # Skip certain locales
      (puts "Skipping #{path}"; next) if File.basename(path, ".yml") =~ skips
      puts "Deleting selected keys from #{path}"
      orig_content = File.open(path, 'r') {|file| file.read}
      File.open(path, 'w') {|file| orig_content.each_line {|line| file.puts line unless line.chomp =~ delete_regex}}
    end
  end
  
  desc <<-END_DESC
Adds a new top-level translation string to all locale file (only works for childless keys, probably doesn\'t work on windows, doesn't check for duplicates).

Options:
  key="some_key=foo"
  key1="another_key=bar"
  key_fb="foo=bar"         Keys to add in the form key=value, every option of the form key[,\\d,_*] will be recognised
  skip=en,de               Comma-separated list of locale files to ignore (filename without extension)
END_DESC

  task :add_key do
    dir = ENV['DIR'] || './config/locales'
    files = Dir.glob(File.join(dir,'*.yml'))
    skips = ENV['skip'] ? Regexp.union(ENV['skip'].split(',')) : nil
    keys_regex = /\Akey(\d+|_.+)?\z/
    adds = ENV.reject {|k,v| !(k =~ keys_regex)}.values.collect {|v| Array.new v.split("=",2)}
    key_list = adds.collect {|v| v[0]}.join(", ")

    files.each do |path|
      # Skip certain locales
      (puts "Skipping #{path}"; next) if File.basename(path, ".yml") =~ skips
      # TODO: Check for dupliate/existing keys
      puts "Adding #{key_list} to #{path}"
      File.open(path, 'a') do |file|
        adds.each do |kv|
          Hash[*kv].to_yaml.each_line do |line|
            file.puts "  #{line}" unless (line =~ /^---/ || line.empty?)
          end
        end
      end
    end
  end
end