feat(i18n): add language preference management functionality

src/i18n/index.js

@@ -102,6 +102,7 @@ export {
   getPrimaryLanguageSubtag,
   getLocale,
   getMessages,
+  getSupportedLocaleList,
   isRtl,
   handleRtl,
   mergeMessages,
@@ -122,3 +123,7 @@ export {
   getLanguageList,
   getLanguageMessages,
 } from './languages';
+
+export {
+  changeUserSessionLanguage,
+} from './languageManager';

src/i18n/languageApi.js

@@ -0,0 +1,59 @@
+import { getConfig } from '../config';
+import { getAuthenticatedHttpClient, getAuthenticatedUser } from '../auth';
+import { convertKeyNames, snakeCaseObject } from '../utils';
+
+/**
+ * Updates user language preferences via the preferences API.
+ *
+ * This function gets the authenticated user, converts preference data to snake_case
+ * and formats specific keys according to backend requirements before sending the PATCH request.
+ * If no user is authenticated, the function returns early without making the API call.
+ *
+ * @param {Object} preferenceData - The preference parameters to update (e.g., { prefLang: 'en' }).
+ * @returns {Promise} - A promise that resolves when the API call completes successfully,
+ *                      or rejects if there's an error with the request. Returns early if no user is authenticated.
+ */
+export async function updateAuthenticatedUserPreferences(preferenceData) {
+  const user = getAuthenticatedUser();
+  if (!user) {
+    return Promise.resolve();
+  }
+
+  const snakeCaseData = snakeCaseObject(preferenceData);
+  const formattedData = convertKeyNames(snakeCaseData, {
+    pref_lang: 'pref-lang',
+  });
+
+  return getAuthenticatedHttpClient().patch(
+    `${getConfig().LMS_BASE_URL}/api/user/v1/preferences/${user.username}`,
+    formattedData,
+    { headers: { 'Content-Type': 'application/merge-patch+json' } },
+  );
+}
+
+/**
+ * Sets the language for the current session using the setlang endpoint.
+ *
+ * This function sends a POST request to the LMS setlang endpoint to change
+ * the language for the current user session.
+ *
+ * @param {string} languageCode - The language code to set (e.g., 'en', 'es', 'ar').
+ *                               Should be a valid ISO language code supported by the platform.
+ * @returns {Promise} - A promise that resolves when the API call completes successfully,
+ *                      or rejects if there's an error with the request.
+ */
+export async function setSessionLanguage(languageCode) {
+  const formData = new FormData();
+  formData.append('language', languageCode);
+
+  return getAuthenticatedHttpClient().post(
+    `${getConfig().LMS_BASE_URL}/i18n/setlang/`,
+    formData,
+    {
+      headers: {
+        Accept: 'application/json',
+        'X-Requested-With': 'XMLHttpRequest',
+      },
+    },
+  );
+}

src/i18n/languageApi.test.js

@@ -0,0 +1,56 @@
+import { updateAuthenticatedUserPreferences, setSessionLanguage } from './languageApi';
+import { getConfig } from '../config';
+import { getAuthenticatedHttpClient, getAuthenticatedUser } from '../auth';
+
+jest.mock('../config');
+jest.mock('../auth');
+
+const LMS_BASE_URL = 'http://test.lms';
+
+describe('languageApi', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+    getConfig.mockReturnValue({ LMS_BASE_URL });
+    getAuthenticatedUser.mockReturnValue({ username: 'testuser', userId: '123' });
+  });
+
+  describe('updateAuthenticatedUserPreferences', () => {
+    it('should send a PATCH request with correct data', async () => {
+      const patchMock = jest.fn().mockResolvedValue({});
+      getAuthenticatedHttpClient.mockReturnValue({ patch: patchMock });
+
+      await updateAuthenticatedUserPreferences({ prefLang: 'es' });
+
+      expect(patchMock).toHaveBeenCalledWith(
+        `${LMS_BASE_URL}/api/user/v1/preferences/testuser`,
+        expect.any(Object),
+        expect.objectContaining({ headers: expect.any(Object) }),
+      );
+    });
+
+    it('should return early if no authenticated user', async () => {
+      const patchMock = jest.fn().mockResolvedValue({});
+      getAuthenticatedHttpClient.mockReturnValue({ patch: patchMock });
+      getAuthenticatedUser.mockReturnValue(null);
+
+      await updateAuthenticatedUserPreferences({ prefLang: 'es' });
+
+      expect(patchMock).not.toHaveBeenCalled();
+    });
+  });
+
+  describe('setSessionLanguage', () => {
+    it('should send a POST request to setlang endpoint', async () => {
+      const postMock = jest.fn().mockResolvedValue({});
+      getAuthenticatedHttpClient.mockReturnValue({ post: postMock });
+
+      await setSessionLanguage('ar');
+
+      expect(postMock).toHaveBeenCalledWith(
+        `${LMS_BASE_URL}/i18n/setlang/`,
+        expect.any(FormData),
+        expect.objectContaining({ headers: expect.any(Object) }),
+      );
+    });
+  });
+});

src/i18n/languageManager.js

@@ -0,0 +1,37 @@
+import { handleRtl, LOCALE_CHANGED } from './lib';
+import { publish } from '../pubSub';
+import { logError } from '../logging';
+import { updateAuthenticatedUserPreferences, setSessionLanguage } from './languageApi';
+
+/**
+ * Changes the user's language preference and applies it to the current session.
+ *
+ * This comprehensive function handles the complete language change process:
+ * 1. Sets the language cookie with the selected language code
+ * 2. If a user is authenticated, updates their server-side preference in the backend
+ * 3. Updates the session language through the setlang endpoint
+ * 4. Publishes a locale change event to notify other parts of the application
+ *
+ * @param {string} languageCode - The selected language locale code (e.g., 'en', 'es', 'ar').
+ *                               Should be a valid ISO language code supported by the platform.
+ * @param {boolean} [forceReload=false] - Whether to force a page reload after changing the language.
+ * @returns {Promise} - A promise that resolves when all operations complete.
+ *
+ */
+export async function changeUserSessionLanguage(
+  languageCode,
+  forceReload = false,
+) {
+  try {
+    await updateAuthenticatedUserPreferences({ prefLang: languageCode });
+    await setSessionLanguage(languageCode);
+    handleRtl(languageCode);
+    publish(LOCALE_CHANGED, languageCode);
+  } catch (error) {
+    logError(error);
+  }
+
+  if (forceReload) {
+    window.location.reload();
+  }
+}

src/i18n/languageManager.test.js

@@ -0,0 +1,59 @@
+import { changeUserSessionLanguage } from './languageManager';
+import { handleRtl, LOCALE_CHANGED } from './lib';
+import { logError } from '../logging';
+import { publish } from '../pubSub';
+import { updateAuthenticatedUserPreferences, setSessionLanguage } from './languageApi';
+
+jest.mock('./lib');
+jest.mock('../logging');
+jest.mock('../pubSub');
+jest.mock('./languageApi');
+
+describe('languageManager', () => {
+  let mockReload;
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+
+    mockReload = jest.fn();
+    Object.defineProperty(window, 'location', {
+      configurable: true,
+      writable: true,
+      value: { reload: mockReload },
+    });
+
+    updateAuthenticatedUserPreferences.mockResolvedValue({});
+    setSessionLanguage.mockResolvedValue({});
+  });
+
+  describe('changeUserSessionLanguage', () => {
+    it('should perform complete language change process', async () => {
+      await changeUserSessionLanguage('fr');
+      expect(updateAuthenticatedUserPreferences).toHaveBeenCalledWith({
+        prefLang: 'fr',
+      });
+      expect(setSessionLanguage).toHaveBeenCalledWith('fr');
+      expect(handleRtl).toHaveBeenCalledWith('fr');
+      expect(publish).toHaveBeenCalledWith(LOCALE_CHANGED, 'fr');
+      expect(mockReload).not.toHaveBeenCalled();
+    });
+
+    it('should handle errors gracefully', async () => {
+      updateAuthenticatedUserPreferences.mockRejectedValue(new Error('fail'));
+      await changeUserSessionLanguage('es', true);
+      expect(logError).toHaveBeenCalled();
+    });
+
+    it('should call updateAuthenticatedUserPreferences even when user is not authenticated', async () => {
+      await changeUserSessionLanguage('en', true);
+      expect(updateAuthenticatedUserPreferences).toHaveBeenCalledWith({
+        prefLang: 'en',
+      });
+    });
+
+    it('should reload if forceReload is true', async () => {
+      await changeUserSessionLanguage('de', true);
+      expect(mockReload).toHaveBeenCalled();
+    });
+  });
+});

src/i18n/lib.js

@@ -184,6 +184,28 @@ export function getMessages(locale = getLocale()) {
   return messages[locale];
 }
 
+/**
+ * Returns the list of supported locales based on the configured messages.
+ * This list is dynamically generated from the translation messages that were
+ * provided during i18n configuration. Always includes the current locale.
+ *
+ * @throws An error if i18n has not yet been configured.
+ * @returns {string[]} Array of supported locale codes
+ * @memberof module:Internationalization
+ */
+export function getSupportedLocaleList() {
+  if (messages === null) {
+    throw new Error('getSupportedLocaleList called before configuring i18n. Call configure with messages first.');
+  }
+
+  const locales = Object.keys(messages);
+  if (!locales.includes('en')) {
+    locales.push('en');
+  }
+
+  return locales;
+}
+
 /**
  * Determines if the provided locale is a right-to-left language.
  *

src/i18n/lib.test.js

@@ -4,6 +4,7 @@ import {
   getPrimaryLanguageSubtag,
   getLocale,
   getMessages,
+  getSupportedLocaleList,
   isRtl,
   handleRtl,
   getCookies,
@@ -184,6 +185,32 @@ describe('lib', () => {
     });
   });
 
+  describe('getSupportedLocales', () => {
+    describe('when configured', () => {
+      beforeEach(() => {
+        configure({
+          loggingService: { logError: jest.fn() },
+          config: {
+            ENVIRONMENT: 'production',
+            LANGUAGE_PREFERENCE_COOKIE_NAME: 'yum',
+          },
+          messages: {
+            'es-419': { message: 'es-hah' },
+            de: { message: 'de-hah' },
+            'en-us': { message: 'en-us-hah' },
+            fr: { message: 'fr-hah' },
+          },
+        });
+      });
+
+      it('should return an array of supported locale codes', () => {
+        const supportedLocales = getSupportedLocaleList();
+        expect(Array.isArray(supportedLocales)).toBe(true);
+        expect(supportedLocales).toEqual(['es-419', 'de', 'en-us', 'fr', 'en']);
+      });
+    });
+  });
+
   describe('isRtl', () => {
     it('should be true for RTL languages', () => {
       expect(isRtl('ar')).toBe(true);