const languageCodes = Object.keys(require('../lib/languages'))

var codes = {
  da: 'da',
  en: 'en',
  es: 'es',
  ja: 'ja',
  pt: 'pt',
  zh: 'cn',
}

function convertLanguageCode(language) {
  var code = language.substring(0,2);
  return codes[code] || code;
}

module.exports = function detectLanguage (req, res, next) {
  // determine language code from first part of URL, or default to English
  // /en/articles/foo
  //  ^^
  const firstPartOfPath = req.path.split('/')[1]

  req.language = languageCodes.includes(firstPartOfPath) ? firstPartOfPath : 'en'
  
  // Detecting browser language by user preference
  const browserLanguage = req.headers["accept-language"].split(",")[0]
  req.userLanguage = convertLanguageCode(browserLanguage)

  return next()
}