fix(web): i18n explicit lang ignored (authelia#3961)

This fixes an issue where explicit languages such as nl-NL, pt-PT, zh-CH, and zh-TW are ignored even though they're supported.

crowdin.yml

@@ -12,5 +12,8 @@ files:
         "en-EN": en
         "es-ES": es
         "fr-FR": fr
+        "nl-NL": nl
+        "pt-PT": pt
         "ru-RU": ru
+        "zh-CH": zh
 ...

internal/server/asset.go

@@ -11,6 +11,7 @@ import (
 	"net/http"
 	"path"
 	"path/filepath"
+	"strings"
 
 	"github.com/valyala/fasthttp"
 
@@ -71,8 +72,23 @@ func newLocalesEmbeddedHandler() (handler fasthttp.RequestHandler) {
 	entries, err := locales.ReadDir("locales")
 	if err == nil {
 		for _, entry := range entries {
-			if entry.IsDir() && len(entry.Name()) == 2 {
-				languages = append(languages, entry.Name())
+			if entry.IsDir() {
+				var lng string
+
+				switch len(entry.Name()) {
+				case 2:
+					lng = entry.Name()
+				case 0:
+					continue
+				default:
+					lng = strings.SplitN(entry.Name(), "-", 2)[0]
+				}
+
+				if utils.IsStringInSlice(lng, languages) {
+					continue
+				}
+
+				languages = append(languages, lng)
 			}
 		}
 	}
@@ -94,7 +110,7 @@ func newLocalesEmbeddedHandler() (handler fasthttp.RequestHandler) {
 		var data []byte
 
 		if data, err = locales.ReadFile(fmt.Sprintf("locales/%s/%s.json", locale, namespace)); err != nil {
-			if variant != "" && utils.IsStringInSliceFold(language, languages) {
+			if utils.IsStringInSliceFold(language, languages) {
 				data = []byte("{}")
 			}
 

web/src/i18n/index.ts

@@ -26,15 +26,16 @@ i18n.use(Backend)
             de: ["en"],
             es: ["en"],
             fr: ["en"],
-            "nl-NL": ["en"],
-            "pt-PT": ["en"],
+            nl: ["en"],
+            pt: ["en"],
             ru: ["en"],
             sv: ["en"],
             "sv-SE": ["sv", "en"],
-            "zh-CN": ["en"],
-            "zh-TW": ["en"],
+            zh: ["en"],
+            "zh-CN": ["zh", "en"],
+            "zh-TW": ["zh", "en"],
         },
-        supportedLngs: ["en", "de", "es", "fr", "nl-NL", "pt-PT", "ru", "sv", "sv-SE", "zh-CN", "zh-TW"],
+        supportedLngs: ["en", "de", "es", "fr", "nl", "pt", "ru", "sv", "sv-SE", "zh", "zh-CN", "zh-TW"],
         lowerCaseLng: false,
         nonExplicitSupportedLngs: true,
         interpolation: {