<?php
        /////////////////////////////////////////////////////////
        //
        //  AHNAR CSA3004 APT University of Malta
        //  Ian Bugeja 2005
        //
        //////////////////////////////////////////////////////////

        session_start();
        header("Cache-control: private"); // IE 6 Fix.

        $visited = &$_SESSION['visited'];
        $ahneg = $_REQUEST['ahneg'];

        $vsize = count($visited);
        $pneg = 0;
        for($i=$vsize; $i >= 0; $i--)
        {
                if ($visited[$i] == $ahneg) { $pneg = $i; break; }
        }
        //$pneg = in_array($ahneg, $visited);

        $backurl = $visited[$pneg -1];
        unset($visited[$pneg]); //remove
        $_SESSION['visited'] = $visited;

        if ($backurl == "")
        {
                $_SESSION = array(); //empty
                header("Location: http://" . $_SERVER['HTTP_HOST']);
                die("");
        }

        //Must Remove popular keywords from keyword list
        if (isset($_SESSION['keywords'])) //keywords in session exists
        foreach($_SESSION['keywords'] as &$okey)
        {
                if (isset($_SESSION['latestkeys']))
                foreach($_SESSION['latestkeys'] as $l)
                {
                        if ($okey[0] == $l[0])
                        {
                                $okey[1] = $okey[1] - $l[1] - 2; //reduce occurance by 2 as a penalty
                                $okey[4] = $okey[4] - 1; //reduce updated times
                        }
                }
        }

        unset($_SESSION['latestkeys']);

        //dirname($_SERVER['PHP_SELF']) .
        header("Location: http://" . $_SERVER['HTTP_HOST'] . "/ahnar.php?ahnarback=true&ahnarurl=" . $backurl);
?>