From b8c6de6b57c528e9240faf580bc707695ee578be Mon Sep 17 00:00:00 2001
From: Prasanna LMSACE <prasanna_t@lmsace.com>
Date: Fri, 15 Sep 2023 14:19:15 +0530
Subject: [PATCH] Improved menus and items language restriction based on
 current language. - Fix #358 (UN-235)

---
 classes/smartmenu.php  | 22 ++++++++++++++++++++++
 smartmenus/menulib.php | 21 ++++++++++-----------
 2 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/classes/smartmenu.php b/classes/smartmenu.php
index f88137791ef..ff338a22c75 100644
--- a/classes/smartmenu.php
+++ b/classes/smartmenu.php
@@ -939,6 +939,9 @@ public static function build_smartmenu() {
 
         $nodes = [];
 
+        // Verify the language changes in user session, if changed than purge the menus and items cache for the user session.
+        self::verify_lang_session_changes();
+
         $cache = cache::make('theme_boost_union', 'smartmenus');
         // Fetch the list of menus from cache.
         $topmenus = $cache->get(self::CACHE_MENUSLIST);
@@ -978,4 +981,23 @@ public static function build_smartmenu() {
 
         return $nodes;
     }
+
+    /**
+     * Verifies and handles changes in the session language.
+     * Clears cached smart menus and items when the user changes the language using the language menu.
+     *
+     * @return void
+     */
+    protected static function verify_lang_session_changes() {
+        global $SESSION, $USER;
+        // Make sure the lang is updated for the session.
+        if ($lang = optional_param('lang', '', PARAM_SAFEDIR)) {
+            // Confirm the cache is not already purged for this language change. To avoid multiple purge.
+            if (!isset($SESSION->prevlang) || $SESSION->prevlang != $lang) {
+                // Set the purge cache preference for this session user. Cache will purged in the build_smartmenu method.
+                \smartmenu_helper::set_user_purgecache($USER->id);
+                $SESSION->prevlang = $lang; // Save this lang for verification.
+            }
+        }
+    }
 }
diff --git a/smartmenus/menulib.php b/smartmenus/menulib.php
index fc926d2a30e..62d59b2fb39 100644
--- a/smartmenus/menulib.php
+++ b/smartmenus/menulib.php
@@ -98,8 +98,10 @@ public function verify_access_restrictions() {
         // Restriction by cohorts.
         $this->restriction_bycohorts($query);
 
-        // REstriction by lanuages.
-        $this->restriction_bylanguage($query);
+        // Restriction by lanuages.
+        if (!$this->restriction_bylanguage()) {
+            return false;
+        }
 
         // Restriction by date. Menu configured date is not started or already ended then hide the menu.
         if (!$this->restriction_bydate()) {
@@ -188,24 +190,21 @@ public function restriction_bycohorts(&$query) {
     }
 
     /**
-     * Generate the queries and params to verify the user has the language which is contained in the current data.
+     * Verify the menu has restricted based on the current language.
      *
-     * @param stdclass $query Array which contains elements for DB conditions, selectors and params.
-     * @return void
+     * @return bool True if the menu is avialble for this lanauge, otherwise false menu will not shown to current user.
      */
-    public function restriction_bylanguage(&$query) {
+    public function restriction_bylanguage() {
         global $DB;
 
         $languages = $this->data->languages;
         if (empty($languages)) {
             return true;
         }
-        list($insql, $inparam) = $DB->get_in_or_equal($languages, SQL_PARAMS_NAMED, 'la');
+        // Current language selected for this session.
+        $lang = current_language();
 
-        if (!empty($inparam)) {
-            $query->where[] = "u.lang $insql";
-            $query->params += $inparam;
-        }
+        return in_array($lang, $languages); // This item is available for the current language.
     }
 
     /**