Extracting i18n functionality to i18n core library (#16914)

* extracting i18n functionality to i18n core library

* Removing utils.T

* Adding documentation and changing one function name for better explanation

* Changing other missing utils.T

* Adding license string

* Renaming corelibs to pkg

* Renaming corelibs to pkg (moving directory)

* Renaming from pkg to shared

* Fixing bodyPage.Html casing

* Fixing merges

* Fixing merge problem

* Fixing tests

utils/i18n.go

@@ -5,135 +5,25 @@ package utils
 
 import (
 	"fmt"
-	"io/ioutil"
-	"net/http"
 	"os"
 	"path/filepath"
-	"strings"
 
-	"github.com/mattermost/go-i18n/i18n"
-
-	"github.com/mattermost/mattermost-server/v5/mlog"
-	"github.com/mattermost/mattermost-server/v5/model"
+	"github.com/mattermost/mattermost-server/v5/shared/i18n"
 	"github.com/mattermost/mattermost-server/v5/utils/fileutils"
 )
 
-var T i18n.TranslateFunc
-var TDefault i18n.TranslateFunc
-var locales map[string]string = make(map[string]string)
-var settings model.LocalizationSettings
-
 // this functions loads translations from filesystem if they are not
 // loaded already and assigns english while loading server config
 func TranslationsPreInit() error {
-	if T != nil {
-		return nil
-	}
-
-	// Set T even if we fail to load the translations. Lots of shutdown handling code will
-	// segfault trying to handle the error, and the untranslated IDs are strictly better.
-	T = TfuncWithFallback("en")
-	TDefault = TfuncWithFallback("en")
-
 	translationsDir := "i18n"
 	if mattermostPath := os.Getenv("MM_SERVER_PATH"); mattermostPath != "" {
 		translationsDir = filepath.Join(mattermostPath, "i18n")
 	}
 
-	return InitTranslationsWithDir(translationsDir)
-}
-
-func InitTranslations(localizationSettings model.LocalizationSettings) error {
-	settings = localizationSettings
-
-	var err error
-	T, err = GetTranslationsBySystemLocale()
-	return err
-}
-
-func InitTranslationsWithDir(dir string) error {
-	i18nDirectory, found := fileutils.FindDirRelBinary(dir)
+	i18nDirectory, found := fileutils.FindDirRelBinary(translationsDir)
 	if !found {
-		return fmt.Errorf("unable to find i18n directory at %q", dir)
+		return fmt.Errorf("unable to find i18n directory at %q", translationsDir)
 	}
 
-	files, _ := ioutil.ReadDir(i18nDirectory)
-	for _, f := range files {
-		if filepath.Ext(f.Name()) == ".json" {
-			filename := f.Name()
-			locales[strings.Split(filename, ".")[0]] = filepath.Join(i18nDirectory, filename)
-
-			if err := i18n.LoadTranslationFile(filepath.Join(i18nDirectory, filename)); err != nil {
-				return err
-			}
-		}
-	}
-
-	return nil
-}
-
-func GetTranslationsBySystemLocale() (i18n.TranslateFunc, error) {
-	locale := *settings.DefaultServerLocale
-	if _, ok := locales[locale]; !ok {
-		mlog.Warn("Failed to load system translations for", mlog.String("locale", locale), mlog.String("attempting to fall back to default locale", model.DEFAULT_LOCALE))
-		locale = model.DEFAULT_LOCALE
-	}
-
-	if locales[locale] == "" {
-		return nil, fmt.Errorf("failed to load system translations for '%v'", model.DEFAULT_LOCALE)
-	}
-
-	translations := TfuncWithFallback(locale)
-	if translations == nil {
-		return nil, fmt.Errorf("failed to load system translations")
-	}
-
-	mlog.Info("Loaded system translations", mlog.String("for locale", locale), mlog.String("from locale", locales[locale]))
-	return translations, nil
-}
-
-func GetUserTranslations(locale string) i18n.TranslateFunc {
-	if _, ok := locales[locale]; !ok {
-		locale = model.DEFAULT_LOCALE
-	}
-
-	translations := TfuncWithFallback(locale)
-	return translations
-}
-
-func GetTranslationsAndLocale(r *http.Request) (i18n.TranslateFunc, string) {
-	// This is for checking against locales like pt_BR or zn_CN
-	headerLocaleFull := strings.Split(r.Header.Get("Accept-Language"), ",")[0]
-	// This is for checking against locales like en, es
-	headerLocale := strings.Split(strings.Split(r.Header.Get("Accept-Language"), ",")[0], "-")[0]
-	defaultLocale := *settings.DefaultClientLocale
-	if locales[headerLocaleFull] != "" {
-		translations := TfuncWithFallback(headerLocaleFull)
-		return translations, headerLocaleFull
-	} else if locales[headerLocale] != "" {
-		translations := TfuncWithFallback(headerLocale)
-		return translations, headerLocale
-	} else if locales[defaultLocale] != "" {
-		translations := TfuncWithFallback(defaultLocale)
-		return translations, headerLocale
-	}
-
-	translations := TfuncWithFallback(model.DEFAULT_LOCALE)
-	return translations, model.DEFAULT_LOCALE
-}
-
-func GetSupportedLocales() map[string]string {
-	return locales
-}
-
-func TfuncWithFallback(pref string) i18n.TranslateFunc {
-	t, _ := i18n.Tfunc(pref)
-	return func(translationID string, args ...interface{}) string {
-		if translated := t(translationID, args...); translated != translationID {
-			return translated
-		}
-
-		t, _ := i18n.Tfunc(model.DEFAULT_LOCALE)
-		return t(translationID, args...)
-	}
+	return i18n.TranslationsPreInit(i18nDirectory)
 }