af83/chouette-core

class LocaleSelector
    def self.locale_for(params, session, user=nil)
        LocaleSelector.new.tap do |selector|
            selector.params = params
            selector.session = session
            selector.user = user
        end.locale
    end

    attr_accessor :params, :session, :user

    delegate :available_locales, :default_locale, to: I18n

  def request_locale
        supported_locale(params['lang'])
  end

  def session_locale
        supported_locale(session[:language])
  end

    def user_locale
        supported_locale(user&.user_locale)
    end

  def locale
        request_locale || session_locale || user_locale || default_locale
  end

    private

    def supported_locale(value)
        value&.to_sym if available_locales.include?(value&.to_sym)
    end
end