Share filelist ảnh PHP có phân trang đầy đủ

<?php

echo '<meta charset="UTF-8">';

// thu muc chua anh

$folder = 'img/';

$filetype = '*.*';    

$files = glob($folder.$filetype);

// ham dem so files trong thu muc

$total = count($files);

// hien so anh o day

$per_page = 2;  

// phan phan trang minh viet khong can phai quan tam  

$last_page = (int)($total / $per_page);    

if(isset($_GET["page"])  && ($_GET["page"] <=$last_page) && ($_GET["page"] > 0) ){

$page = $_GET["page"];

$offset = ($per_page + 1)*($page - 1);      

}else{

$page=1;

$offset=0;      

}    

$max = $offset + $per_page;    

if($max>$total){

$max = $total;

}

// function hien thu nut truoc - sau

function show_pagination($current_page, $last_page){

echo '<div>';

if( $current_page > 1 ){

echo ' <a href="?page='.($current_page-1).'"> Previous</a> - ';

}

if( $current_page < $last_page ){

echo ' <a href="?page='.($current_page+1).'"> Next</a> ';  

}

echo '</div>';

}

echo "<li>Đang ở trang: $page offset</li>";

echo "<li>Tổng ảnh: $total</li>";

// chay vong lap hien thi anh

for($i = $offset; $i< $max; $i++){

$file = $files[$i];

$path_parts = pathinfo($file);

$filename = $path_parts['filename'];        

echo '<p><a href="'.$file.'"><img src="'.$file.'" alt="'.$filename.'" width="200"></a></p>';

}

// nut phan trang

show_pagination($page, $last_page);

?>