2 files changed, 86 insertions, 12 deletions

diff --git a/gui/src/main/index.ts b/gui/src/main/index.ts
index ec67280e12..872c043f89 100644
--- a/gui/src/main/index.ts
+++ b/gui/src/main/index.ts
@@ -34,7 +34,7 @@ import {
   RelaySettingsUpdate,
   TunnelState,
 } from '../shared/daemon-rpc-types';
-import { loadTranslations, messages } from '../shared/gettext';
+import { messages, relayLocations } from '../shared/gettext';
 import { SYSTEM_PREFERRED_LOCALE_KEY } from '../shared/gui-settings-state';
 import { IpcMainEventChannel } from '../shared/ipc-event-channel';
 import log, { ConsoleOutput, Logger } from '../shared/logging';
@@ -65,11 +65,13 @@ import {
   IpcInput,
   OLD_LOG_FILES,
 } from './logging';
+import { loadTranslations } from './load-translations';
 import NotificationController from './notification-controller';
 import { resolveBin } from './proc';
 import ReconnectionBackoff from './reconnection-backoff';
 import TrayIconController, { TrayIconType } from './tray-icon-controller';
 import WindowController from './window-controller';
+import { ITranslations } from '../shared/ipc-schema';
 
 // Only import when running app on Linux.
 const linuxSplitTunneling = process.platform === 'linux' && require('./linux-split-tunneling');
@@ -204,6 +206,7 @@ class ApplicationMain {
   private autoConnectFallbackScheduler = new Scheduler();
 
   private rendererLog?: Logger;
+  private translations: ITranslations = { locale: this.locale };
 
   public run() {
     // Remove window animations to combat window flickering when opening window. Can be removed when
@@ -373,7 +376,7 @@ class ApplicationMain {
 
     this.blockRequests();
 
-    this.updateCurrentLocale();
+    this.translations = this.updateCurrentLocale();
 
     this.daemonRpc.addConnectionObserver(
       new ConnectionObserver(this.onDaemonConnected, this.onDaemonDisconnected),
@@ -1007,6 +1010,7 @@ class ApplicationMain {
       upgradeVersion: this.upgradeVersion,
       guiSettings: this.guiSettings.state,
       wireguardPublicKey: this.wireguardPublicKey,
+      translations: this.translations,
     }));
 
     IpcMainEventChannel.settings.handleSetAllowLan((allowLan: boolean) =>
@@ -1074,7 +1078,7 @@ class ApplicationMain {
 
     IpcMainEventChannel.guiSettings.handleSetPreferredLocale((locale: string) => {
       this.guiSettings.preferredLocale = locale;
-      this.didChangeLocale();
+      return Promise.resolve(this.updateCurrentLocale());
     });
 
     IpcMainEventChannel.account.handleCreate(() => this.createNewAccount());
@@ -1368,15 +1372,13 @@ class ApplicationMain {
 
     log.info(`Detected locale: ${this.locale}`);
 
-    loadTranslations(this.locale, messages);
-  }
-
-  private didChangeLocale() {
-    this.updateCurrentLocale();
-
-    if (this.windowController) {
-      IpcMainEventChannel.locale.notify(this.windowController.webContents, this.locale);
-    }
+    const messagesTranslations = loadTranslations(this.locale, messages);
+    const relayLocationsTranslations = loadTranslations(this.locale, relayLocations);
+    return {
+      locale: this.locale,
+      messages: messagesTranslations,
+      relayLocations: relayLocationsTranslations,
+    };
   }
 
   // Since the app frontend never performs any network requests, all requests originating from the
diff --git a/gui/src/main/load-translations.ts b/gui/src/main/load-translations.ts
new file mode 100644
index 0000000000..63d76f0ac6
--- /dev/null
+++ b/gui/src/main/load-translations.ts
@@ -0,0 +1,72 @@
+import fs from 'fs';
+import { GetTextTranslations, po } from 'gettext-parser';
+import Gettext from 'node-gettext';
+import path from 'path';
+import log from '../shared/logging';
+
+const SOURCE_LANGUAGE = 'en';
+const LOCALES_DIR = path.resolve(__dirname, '../../locales');
+
+export function loadTranslations(
+  currentLocale: string,
+  catalogue: Gettext,
+): GetTextTranslations | undefined {
+  // First look for exact match of the current locale
+  const preferredLocales = [];
+
+  if (currentLocale !== SOURCE_LANGUAGE) {
+    preferredLocales.push(currentLocale);
+  }
+
+  // In case of region bound locale like en-US, fallback to en.
+  const language = Gettext.getLanguageCode(currentLocale);
+  if (currentLocale !== language) {
+    preferredLocales.push(language);
+  }
+
+  const domain = catalogue.domain;
+  for (const locale of preferredLocales) {
+    const parsedTranslations = parseTranslation(locale, domain, catalogue);
+    if (parsedTranslations) {
+      log.info(`Loaded translations ${locale}/${domain}`);
+      catalogue.setLocale(locale);
+      return parsedTranslations;
+    }
+  }
+
+  // Reset the locale to source language if we couldn't load the catalogue for the requested locale
+  // Add empty translations to suppress some of the warnings produces by node-gettext
+  catalogue.addTranslations(SOURCE_LANGUAGE, domain, {});
+  catalogue.setLocale(SOURCE_LANGUAGE);
+  return;
+}
+
+function parseTranslation(
+  locale: string,
+  domain: string,
+  catalogue: Gettext,
+): GetTextTranslations | undefined {
+  const filename = path.join(LOCALES_DIR, locale, `${domain}.po`);
+  let contents: string;
+
+  try {
+    contents = fs.readFileSync(filename, { encoding: 'utf8' });
+  } catch (error) {
+    if (error.code !== 'ENOENT') {
+      log.error(`Cannot read the gettext file "${filename}": ${error.message}`);
+    }
+    return undefined;
+  }
+
+  let translations: GetTextTranslations;
+  try {
+    translations = po.parse(contents);
+  } catch (error) {
+    log.error(`Cannot parse the gettext file "${filename}": ${error.message}`);
+    return undefined;
+  }
+
+  catalogue.addTranslations(locale, domain, translations);
+
+  return translations;
+}