Fix a redirect URL

[Immortal]

Hello everyone,

I've used preg_match_all to replace all of my URLs to be more SEO friendly. However, I tried to use preg_match_all (global_complete hook) for redirects such as showthread.php?p=id#postid and search.php?searchid=id however it does not want to cooperate since they are "redirects" and not URLs...I've tried using the following code.

PHP Code:

$found = preg_match_all('#showthread\.php\?p=([0-9]+)\#post([0-9]+)#i', $output, $matches);

if($found)
{
    // Build an array of ID's
    $ids = array();

    for($i = 0; $i < $found; $i++)
    {
        if(is_numeric($matches[1][$i]))
            $ids[] = $matches[1][$i];
    }
    $ids = implode(',', $ids);

    // Go through each
    $res = $vbulletin->db->query_read("SELECT threadid, postid FROM " . TABLE_PREFIX . "post WHERE postid IN($ids)");

    while($t = $vbulletin->db->fetch_array($res))
    {
       
        $tid = $t['threadid'];
        $pid = $t['postid'];
                $threadinfo = $vbulletin->db->query_first("SELECT title, forumid FROM thread WHERE threadid='$tid'");
        $title = urlize($threadinfo['title']);
        $fid = $threadinfo['forumid'];
        $f = fetch_foruminfo($fid); 
        $fname = urlize($f['title']);



        $output = str_replace("showthread.php?p=$pid#post$pid", "$fname/p-$title-$pid.html#$pid", $output);
    }


} 


But preg_match_all found nothing. Is there a special way I have to do this or in a different hook then global_complete? I really don't want to modify any files if I can stay away from that. Any help would be greatly appreciated