module I18nData

def available_language_codes
  @available_language_codes ||= begin
    files = Dir[File.expand_path('../cache/file_data_provider/languages-*', __dir__)]
    files.map! { |f| f[/languages-(.*)\./, 1] }
  end
end

def countries(language_code = 'EN')
  fetch :countries, language_code do
    data_provider.codes(:countries, normal_to_region_code(language_code.to_s.upcase))
  end
end

def country_code(name)
  recognise_code(:countries, name)
end

def data_provider
  @data_provider ||= begin
    require 'i18n_data/file_data_provider'
    FileDataProvider
  end
end

def data_provider=(provider)
  @cache = nil
  @data_provider = provider
end

def fetch(type, language_code)
  @cache ||= Hash.new { |h, k| h[k] = {} }
  @cache[type].fetch(language_code) { @cache[type][language_code] = yield }
end

def language_code(name)
  recognise_code(:languages, name)
end

def languages(language_code = 'EN')
  fetch :languages, language_code do
    data_provider.codes(:languages, normal_to_region_code(language_code.to_s.upcase))
  end
end

def normal_to_region_code(normal)
  {
    "ZH" => "zh_CN",
    "BN" => "bn_IN"
  }[normal] || normal
end

def recognise_code(type, search)
  search = search.strip
  # common languages first <-> faster in majority of cases
  language_codes = ['EN', 'ES', 'FR', 'DE', 'ZH'] | available_language_codes
  language_codes.each do |language_code|
    options =
      begin
        send(type, language_code)
      rescue NoTranslationAvailable
        next
      end
    options.each do |code, name|
      # support "Dutch" and "Dutch; Flemish", checks for inclusion first to skip the splitting
      # then check for exact match
      return code if name.include?(search) && (name == search || name.split('; ').include?(search))
    end
  end
  nil # not found
end