Philipp König

var langDir = "langs"
var defaultLanguage string
var langs map[string]i18n.TranslateFunc

func Init() {
	if langs == nil {
		langs = make(map[string]i18n.TranslateFunc)
	}

	dirList, _ := ioutil.ReadDir(fmt.Sprintf("%s%s", env.GetPath(), langDir))
	defaultLanguage = config.GetDefaultLanguage()
	hasDefaultLanguage := false

	for _, dir := range dirList {
		lang := dir.Name()
		files, _ := ioutil.ReadDir(fmt.Sprintf("%s%s/%s", env.GetPath(), langDir, lang))

		if lang == defaultLanguage {
			hasDefaultLanguage = true
		}

		for _, file := range files {
			fileName := file.Name()
			err := i18n.LoadTranslationFile(fmt.Sprintf("%s%s/%s/%s", env.GetPath(), langDir, lang, fileName))

			if err != nil {
				panic(fmt.Sprintf("Error loading language file -> %s/%s: %s", lang, fileName, err))
			}

			log.Info.Println("Loaded translation file", "->", fileName)
		}

		var err error
		langs[lang], err = i18n.Tfunc(lang)

		if err != nil {
			panic(fmt.Sprintf("Error parsing language -> %s: %s", lang, err))
		}

		log.Info.Println("Finished loading language", "->", lang)
	}

	if !hasDefaultLanguage {
		panic(fmt.Sprintf("There is no translation for %s", defaultLanguage))
	}
}

func GetUserLanguage(r *http.Request) string {
	ret := config.GetDefaultLanguage()
	userLangs, _, _ := language.ParseAcceptLanguage(r.Header.Get("Accept-Language"))

	for _, userLang := range userLangs {
		userLangStr := strings.Replace(userLang.String(), "-", "_", -1)
		userLangSplitted := strings.Split(userLangStr, "_")

		if LangExists(userLangStr) {
			ret = userLangStr
			break
		} else if len(userLangSplitted) > 1 {
			if LangExists(userLangSplitted[0]) {
				ret = userLangSplitted[0]
				break
			}
		}
	}
	return ret
}

func LangExists(lang string) bool {
	_, ok := langs[lang]
	return ok
}

func GetAll() []string {
	var ret []string
	for lang := range langs {
		ret = append(ret, lang)
	}
	return ret
}

func Get(lang string, key string) string {
	return GetPlural(lang, key, 1)
}

func GetPlural(lang string, key string, amount int) string {
	ret := key

	if LangExists(lang) {
		ret = langs[lang](key, amount)

		if ret == key && lang != defaultLanguage {
			ret = Get(defaultLanguage, key)
		}
	}
	return ret
}