PHP smart pagination

smart_pagination.php

<?php
/**
 * @param int $page
 * @param int $total
 * @param int $range
 *
 * @return array
 */
function getPages(int $page, int $total, int $range): array
{
    if ($total < $range) {
        return range(1, $total);
    }

    $adjacent = floor($range/2);

    // First pages
    if ($page <= $range - $adjacent) {
        $pages = range(1, $range);

        $pages[] = '...';
        $pages[] = $total;

        return $pages;
    }

    // Last pages
    if ($page >= ($total - $range + $adjacent)) {
        $pages = range($total - $range, $total);
        array_unshift($pages, '...');
        array_unshift($pages, 1);

        return $pages;
    }

    $pages = range($page - $adjacent, $page + $adjacent);

    if (reset($pages) > 2) {
        array_unshift($pages, '...');
    }

    array_unshift($pages, 1);

    $pages[] = '...';
    $pages[] = $total;

    return $pages;
}