Landing Page - Joomla if home page - redirect to language landing page version

landing-page.php

<?php
//add at top of template index.php
//GET DEFAULT HOMEPAGE 
$app = JFactory::getApplication();
$menu = $app->getMenu();
if ($menu->getActive() == $menu->getDefault()) {
//LANGUAGE
    // Initialize the language code variable
$lc = ""; 
$host  = $_SERVER['HTTP_HOST'];
$uri   = rtrim(dirname($_SERVER['PHP_SELF']), '/\\');
    
    // Check to see that the global language server variable isset()
    // If it is set, we cut the first two characters from that string
if(isset($_SERVER['HTTP_ACCEPT_LANGUAGE']))
    $lc = substr($_SERVER['HTTP_ACCEPT_LANGUAGE'], 0, 2);

    // Now we simply evaluate that variable to detect specific languages
if($lc == "zh"){
        JFactory::getApplication()->redirect(JURI::base().'landing/default-zh.php');    

    exit();
} 
else { // don't forget the default case if $lc is empty
    JFactory::getApplication()->redirect(JURI::base().'landing/default-en.php');
    exit();
}


 }
?>