Port the change language callback to the Account controller.

application/controllers/Account.php

@@ -101,7 +101,7 @@ class Account extends EA_Controller {
     }
 
     /**
-     * Make sure the username is valid and unique in the database. 
+     * Make sure the username is valid and unique in the database.
      */
     public function validate_username()
     {
@@ -122,4 +122,47 @@ class Account extends EA_Controller {
             json_exception($e);
         }
     }
+
+    /**
+     * Change system language for current user.
+     *
+     * The language setting is stored in session data and retrieved every time the user visits any of the system pages.
+     */
+    public function change_language()
+    {
+        try
+        {
+            // Check if language exists in the available languages.
+            
+            $found = FALSE;
+
+            foreach (config('available_languages') as $lang)
+            {
+                if ($lang == request('language'))
+                {
+                    $found = TRUE;
+                    break;
+                }
+            }
+
+            if ( ! $found)
+            {
+                throw new Exception('Translations for the given language does not exist (' . request('language') . ').');
+            }
+
+            $language = request('language');
+
+            session(['language' => $language]);
+
+            config(['language' => $language]);
+
+            json_response([
+                'success' => TRUE
+            ]);
+        }
+        catch (Throwable $e)
+        {
+            json_exception($e);
+        }
+    }
 }

assets/js/http/account_http_client.js

@@ -53,8 +53,25 @@ App.Http.Account = (function () {
         return $.post(url, data);
     }
 
+    /**
+     * Change language.
+     *
+     * @param {String} language
+     */
+    function changeLanguage(language) {
+        const url = App.Utils.Url.siteUrl('account/change_language');
+
+        const data = {
+            csrf_token: App.Vars.csrf_token,
+            language
+        };
+
+        return $.post(url, data);
+    }
+
     return {
         save,
-        validateUsername
+        validateUsername,
+        changeLanguage
     };
 })();