formatLongMessage paranoid

function formatLongMessage($message, $board, $threadid, $page) {
        $output = '';
        $usemb = (function_exists('mb_substr') && function_exists('mb_strlen')) ? true : false;
        if ($usemb){
                $message_exploded = mb_split('<br>', $message);
                if ((mb_strlen($message) > KU_LINELENGTH || count($message_exploded) > 15) && $page) {
                        $message_shortened = '';
                        for ($i = 0; $i <= 14; $i++) {
                                if (isset($message_exploded[$i])) {
                                        $message_shortened .= $message_exploded[$i] . '<br>';
                                }
                        }
                        if (mb_strlen($message_shortened) > KU_LINELENGTH) {
                                $message_rest = mb_substr($message_shortened, KU_LINELENGTH);
                                $message_shortened = mb_substr($message_shortened, 0, KU_LINELENGTH);
                                $open_pos = mb_strpos($message_rest, '<');
                                $close_pos = mb_strpos($message_rest, '>');
                                if($open_pos === FALSE and $close_pos or $close_pos < $open_pos){
                                        $message_shortened .= mb_substr($message_rest, 0, $close_pos + 1);
                                }
                        }
                        $message_shortened = closeOpenTags($message_shortened);

                        $output = $message_shortened . '<div class="abbrev">' . "\n" .
                        '       ' . sprintf(_gettext('Message too long. Click %shere%s to view the full text.'), '<a href="' . KU_BOARDSFOLDER . $board . '/res/' . $threadid . '.html">', '</a>') . "\n" .
                        '</div>' . "\n";
                } else {
                        $output .= $message . "\n";
                }
        }
        else{
                $message_exploded = explode('<br>', $message);
                if ((strlen($message) > KU_LINELENGTH || count($message_exploded) > 15) && $page) {
                        $message_shortened = '';
                        for ($i = 0; $i <= 14; $i++) {
                                if (isset($message_exploded[$i])) {
                                        $message_shortened .= $message_exploded[$i] . '<br>';
                                }
                        }
                        if (strlen($message_shortened) > KU_LINELENGTH) {
                                $message_rest = substr($message_shortened, KU_LINELENGTH);
                                $message_shortened = substr($message_shortened, 0, KU_LINELENGTH);
                                $open_pos = strpos($message_rest, '<');
                                $close_pos = strpos($message_rest, '>');
                                if($open_pos === FALSE and $close_pos or $close_pos < $open_pos){
                                        $message_shortened .= substr($message_rest, 0, $close_pos + 1);
                                }
                        }
                        $message_shortened = closeOpenTags($message_shortened);

                        $output = $message_shortened . '<div class="abbrev">' . "\n" .
                        '       ' . sprintf(_gettext('Message too long. Click %shere%s to view the full text.'), '<a href="' . KU_BOARDSFOLDER . $board . '/res/' . $threadid . '.html">', '</a>') . "\n" .
                        '</div>' . "\n";
                } else {
                        $output .= $message . "\n";
                }
        }

        return $output;
}