require 'fedux_org_stdlib/shell_language_detector'
require 'fedux_org_stdlib/logging/logger'
require_library %w(i18n)

# encoding: utf-8
module FeduxOrgStdlib
  # Configuration for language on cli
  #
  # Make sure you have translations for
  # errors:
  #   use_empty_locale:
  #   use_invalid_locale:
  class LocaleConfigurator
    private

    attr_reader :pattern, :detector, :detected_locale, :logger

    public

    def initialize(
      path:,
      default_locale: nil,
      enforce_available_locales: true,
      detector: FeduxOrgStdlib::ShellLanguageDetector.new,
      logger: FeduxOrgStdlib::Logging::Logger.new
    )
      @pattern         = File.join(path, '*.yml')
      @detector        = detector
      @detected_locale = detect_locale(overwrite: default_locale)
      @logger          = logger

      I18n::Backend::Simple.send(:include, I18n::Backend::Fallbacks)
      I18n.load_path = locale_files
      I18n.backend.load_translations

      I18n.default_locale            = @detected_locale
      I18n.available_locales         = available_locales
      I18n.enforce_available_locales = enforce_available_locales
    end

    def use_locale(l)
      l = l.to_sym

      if l.blank?
        logger.warn I18n.t('errors.use_empty_locale', codes: available_locales.to_list, fallback_locale: detected_locale)
        return
      end

      unless valid_locale?(l)
        logger.warn I18n.t('errors.use_invalid_locale', codes: available_locales.to_list, fallback_locale: detected_locale)
        return
      end

      I18n.locale = l
    end

    def available_locales
      locale_files.map { |f| File.basename(f, '.yml').to_sym }
    end

    def t(*args, &block)
      I18n.t(*args, &block)
    end

    def validate_and_return_locale(l)
      return l.to_sym if valid_locale? l

      logger.warn I18n.t('errors.use_invalid_locale', codes: available_locales.to_list, fallback_locale: detected_locale)

      detected_locale
    end

    private

    def valid_locale?(l)
      available_locales.include? l.to_sym
    end

    def detect_locale(overwrite:)
      options = {}
      options[:allowed] = available_locales
      options[:overwrite] = overwrite.to_sym if overwrite

      detector.detect(**options).language_code
    end

    def locale_files
      @locale_files ||= Dir.glob(pattern)
    end
  end
end