gistfile1.rb

def current_language
  # if a "lang" URL parameter is specified, force it
  return params[:lang] if params[:lang].present?
  
  # if the user is logged in, use their language preference stored in the DB
  return current_user.language if logged_in?

  # if the user has manually selected a language, return that
  return cookies[:language_code] if cookies[:language_code]
  
  # if the user is not logged in or has not selected a language
  # attempt to determine a language based on their IP
  LANGUAGE_TO_COUNTRY_MAPPINGS.keys.each { |lang| return lang if LANGUAGE_TO_COUNTRY_MAPPINGS[lang].include?(current_country) }
  
  # if all else fails, return english
  return 'eng'
end