How to make product diapason pagination in OpenCart 2.x? - php

Question

I have OpenCart 2.1 and the website has such pagination (see screenshot)
default pagination
Here is the question: How to make like a product diapason pagination in OpenCart?
When I say the diapason pagination, I mean this (see screenshot please)
diapason pagination screenshot
Here is some code that is responsible for the formation of pagination.
<?php
class Pagination {
public $total = 0;
public $page = 1;
public $limit = 20;
public $num_links = 8;
public $url = '';
public $text_first = '|<';
public $text_last = '>|';
public $text_next = '>';
public $text_prev = '<';
public function render() {
$total = $this->total;
if ($this->page < 1) {
$page = 1;
} else {
$page = $this->page;
}
if (!(int)$this->limit) {
$limit = 10;
} else {
$limit = $this->limit;
}
$num_links = $this->num_links;
$num_pages = ceil($total / $limit);
$this->url = str_replace('%7Bpage%7D', '{page}', $this->url);
$output = '<ul class="pagination">';
if ($page > 1) {
$output .= '<li>' . $this->text_first . '</li>';
$output .= '<li>' . $this->text_prev . '</li>';
}
if ($num_pages > 1) {
if ($num_pages <= $num_links) {
$start = 1;
$end = $num_pages;
} else {
$start = $page - floor($num_links / 2);
$end = $page + floor($num_links / 2);
if ($start < 1) {
$end += abs($start) + 1;
$start = 1;
}
if ($end > $num_pages) {
$start -= ($end - $num_pages);
$end = $num_pages;
}
}
for ($i = $start; $i <= $end; $i++) {
if ($page == $i) {
$output .= '<li class="active"><span>' . $i . '</span></li>';
} else {
$output .= '<li>' . $i . '</li>';
}
}
}
if ($page < $num_pages) {
$output .= '<li>' . $this->text_next . '</li>';
$output .= '<li>' . $this->text_last . '</li>';
}
$output .= '</ul>';
if ($num_pages > 1) {
return $output;
} else {
return '';
}
}
}