PHP Exam - Facebook Posts

<?php

date_default_timezone_set('Europe/Sofia');

$text = trim($_GET['text']);
$postsList = preg_split('/\r?\n/', $text, -1, PREG_SPLIT_NO_EMPTY);
$posts = array();
$result = '';

foreach ($postsList as $key => $p) {

    $post = explode(';', $p);
    $commentsStr = '';

    $posts[$key]['name'] = trim($post[0]);
    $posts[$key]['time'] = strtotime(trim($post[1]));
    $posts[$key]['post'] = trim($post[2]);
    $posts[$key]['likes'] = trim($post[3]);

    if ($post[4]) {
        $com = explode('/', $post[4]);
        $comments = '';

        foreach ($com as $c) {
            $comments .= '<p>' . htmlspecialchars(trim($c)) . '</p>';
        }

        $commentsStr = '<div class="comments">' . $comments . '</div>';
    }
    $posts[$key]['comments'] = $commentsStr;
}

$posts = multisort($posts, SORT_DESC, 'time');

foreach($posts as $post) {
    $result .= '<article>';
    $result .= '<header><span>' . htmlspecialchars($post['name']) . '</span><time>' . date('j F Y', $post['time']) . '</time></header>';
    $result .= '<main><p>' . htmlspecialchars($post['post']) . '</p></main>';
    $result .= '<footer><div class="likes">' . htmlspecialchars($post['likes']) . ' people like this</div>' . $post['comments'] . '</footer>';
    $result .= '</article>';
}

echo $result;

function multisort($arr, $ord, $property) {
    foreach ($arr as $id => $val) {
        $key[$id] = $val[$property];
    }
    array_multisort($key, $ord, $arr);
    return $arr;
}