if (count($subjects) > 0) {
         echo '<table class="tableLeft">';
         foreach ($subjects as $sub) {
             if ($userData['rol'] != 'student') {
                 //Geen link
                 echo '<tr><td>' . $sub['vaknaam'] . '</td></tr>';
             } else {
                 //Wel link
                 echo '<tr><td><a href="viewnotes.php?student=' . $targetUser . '&subject=' . $sub['vakId'] . '">' . $sub['vaknaam'] . '</a></td></tr>';
             }
         }
         echo '</table>';
     } else {
         echo '<p>Geen vakken gevonden!</p>';
     }
     if (portfolio_user_is_of_type(array('admin'))) {
         echo '<hr>';
         echo '<p></p>';
         echo '<h3>Voeg vak toe aan gebruiker</h3>';
         $allSubjects = portfolio_get_subjects();
         if (count($allSubjects) > 0) {
             echo '<table class="tableLeft">';
             foreach ($allSubjects as $sub) {
                 echo '<tr><td><a href="addsubjecttouser.php?user='******'&subject=' . $sub['vakId'] . '" target="_blank">' . $sub['vaknaam'] . '</a></td></tr>';
             }
             echo '</table>';
         }
     }
 } else {
     echo '<p>Gebruiker niet gevonden!</p>';
 }
?>
                </div>
            </div>
            <div id="content">
            <?php 
if (isset($_SESSION['user'])) {
    //Alles
    echo "<h2>Welkom " . $_SESSION['user']['voornaam'] . " " . $_SESSION['user']['achternaam'] . "</h2>";
    //Als een student ingelogd is, dan is targetUser de student. Anders pakken we hem via GET
    $targetUser = portfolio_user_is_of_type(array('student')) ? $_SESSION['user']['gebruikersId'] : filter_input(INPUT_GET, 'student', FILTER_VALIDATE_INT);
    if ($targetUser) {
        $mats = portfolio_get_user_materials($targetUser);
        $userData = portfolio_get_user_details($targetUser);
        if ($userData) {
            echo '<h2>Materialen van ' . $userData['voornaam'] . ' ' . $userData['achternaam'] . '</h2>';
            if (!portfolio_user_is_of_type(array('student'))) {
                echo '<p><a href="students.php">Terug naar studentenoverzicht</a></p>';
            } else {
                echo '<p><a href="upload.php">Upload nieuw materiaal</a></p>';
            }
            echo '<hr>';
        }
        if (count($mats) > 0) {
            echo '<table class="tableLeft">';
            foreach ($mats as $mat) {
                echo '<tr><td><a href="viewmaterial.php?material=' . $mat['materiaalId'] . '">' . $mat['naam'] . '</a></td></tr>';
            }
            echo '</table>';
        } else {
            echo '<p>Geen materialen gevonden!</p>';
        }
            <div id="content">
            <?php 
if (isset($_SESSION['user'])) {
    //$matId = filter_input(INPUT_GET, 'material', FILTER_VALIDATE_INT);
    $matId = filter_input(INPUT_GET, 'material', FILTER_VALIDATE_INT);
    if ($matId) {
        //Alles
        echo "<h2>Welkom " . $_SESSION['user']['voornaam'] . " " . $_SESSION['user']['achternaam'] . "</h2>";
        $matData = portfolio_get_material($matId);
        $noteData = portfolio_get_note($matId);
        if ($matData && $noteData) {
            echo '<h2>Verwijder cijfer voor ' . $matData['naam'] . '</h2>';
            /*
             * Checks + verwijderen van materiaal.
             */
            if (portfolio_user_is_of_type(array('admin')) || $_SESSION['user']['gebruikersId'] == $noteData['beoordelaarId']) {
                $pwCorrect = false;
                $deleted = false;
                if (isset($_POST['submit']) && isset($_SESSION['user']) && $matId) {
                    $userId = $_SESSION['user']['gebruikersId'];
                    $userPass = filter_input(INPUT_POST, 'userPass');
                    $link = portfolio_connect();
                    if ($link) {
                        $sql = "SELECT * FROM " . TABLE_USER . " WHERE gebruikersId='" . mysqli_real_escape_string($link, $userId) . "'";
                        $result = mysqli_query($link, $sql);
                        if ($result !== false) {
                            if (($array = mysqli_fetch_assoc($result)) != null) {
                                if (password_verify($userPass, $array['wachtwoord'])) {
                                    $pwCorrect = true;
                                    $deleted = portfolio_delete_note($matId);
                                }
            </div>
            <div id="content">
            <?php 
if (isset($_SESSION['user'])) {
    //$msgId = filter_input(INPUT_GET, 'material', FILTER_VALIDATE_INT);
    $msgId = filter_input(INPUT_GET, 'message', FILTER_VALIDATE_INT);
    if ($msgId) {
        //Alles
        echo "<h2>Welkom " . $_SESSION['user']['voornaam'] . " " . $_SESSION['user']['achternaam'] . "</h2>";
        $msgData = portfolio_get_guestbook_message($msgId);
        if ($msgData) {
            echo '<h2>Verwijderen gastenboek bericht</h2>';
            /*
             * Checks + verwijderen van materiaal.
             */
            if ($_SESSION['user']['gebruikersId'] === $msgData['ontvangerId'] || portfolio_user_is_of_type(array('admin'))) {
                if (portfolio_delete_guestbook_message($msgId)) {
                    echo '<p>Bericht verwijderd</p>';
                } else {
                    echo '<p>Kon bericht niet verwijderen</p>';
                }
            } else {
                echo '<p>U bent niet gemachtigd dit bericht te verwijderen</p>';
            }
        } else {
            echo '<p>Bericht niet gevonden!</p>';
        }
    }
} else {
    echo "<h2>Log eerst in!</h2>";
    echo '<p><a href="login.php">Klik hier om in te loggen</a></p>';
            <div id="header">
                <?php 
include 'inc/header.php';
?>
            </div>
            <div id="content">
            <?php 
if (isset($_SESSION['user'])) {
    $targetId = filter_input(INPUT_GET, 'student', FILTER_VALIDATE_INT);
    $targetSubject = filter_input(INPUT_GET, 'subject', FILTER_VALIDATE_INT);
    if ($targetId) {
        //Alles
        echo "<h2>Welkom " . $_SESSION['user']['voornaam'] . " " . $_SESSION['user']['achternaam'] . "</h2>";
        $targetData = portfolio_get_user_details($targetId);
        if ($targetData) {
            if ($targetData['rol'] === 'student' && portfolio_user_is_of_type(array('slb', 'docent')) || portfolio_user_is_of_type(array('admin')) || $targetId == $_SESSION['user']['gebruikersId']) {
                echo '<h2>' . $targetData['voornaam'] . ' ' . $targetData['achternaam'] . '</h2>';
                $targetSubjectData = portfolio_get_subject($targetSubject);
                if ($targetSubjectData) {
                    echo '<h3>Cijfers voor vak ' . $targetSubjectData['vaknaam'] . '</h3>';
                } else {
                    echo '<h3>Cijfers</h3>';
                    $targetSubject = 0;
                }
                $notes = portfolio_get_student_notes_ext($targetId, $targetSubject);
                if (count($notes) > 0) {
                    echo '<table class="tableLeft">';
                    echo '<tr><th rel="col">naam materiaal</th><th rel="col">verbonden vakken</th><th rel="col">cijfer</th></tr>';
                    foreach ($notes as $n) {
                        $v = portfolio_get_material_subjects($n['materiaalId']);
                        echo '<tr>';
        <div id="container">
            <div id="header">
                <?php 
include 'inc/header.php';
?>
            </div>
            <div id="content">
            <?php 
if (isset($_SESSION['user'])) {
    $targetId = filter_input(INPUT_GET, 'material', FILTER_VALIDATE_INT);
    if ($targetId) {
        //Alles
        echo "<h2>Welkom " . $_SESSION['user']['voornaam'] . " " . $_SESSION['user']['achternaam'] . "</h2>";
        $targetData = portfolio_get_material($targetId);
        if ($targetData) {
            if ($_SESSION['user']['gebruikersId'] === $targetData['eigenaarId'] || portfolio_user_is_of_type(array('admin'))) {
                echo '<form method="post" action="' . $_SERVER['PHP_SELF'] . '?' . $_SERVER['QUERY_STRING'] . '">';
                echo '<h2>' . $targetData['naam'] . '</h2>';
                //HIER SUBMIT TROEP
                if (isset($_POST['submit'])) {
                    $naam = filter_input(INPUT_POST, 'naam');
                    $isPublic = filter_input(INPUT_POST, 'isOpenbaar');
                    if (!empty($naam)) {
                        switch ($isPublic) {
                            case 0:
                                $isPublic = 0;
                                break;
                            case 1:
                                $isPublic = 1;
                                break;
                            default:
        <link href="css/admin.css" rel="stylesheet" type="text/css">
    </head>
    <body>
        
        <div id="container">
            <div id="header">
                <?php 
include 'inc/header.php';
?>
            </div>
            <div id="content">
            <?php 
if (isset($_SESSION['user'])) {
    $targetId = filter_input(INPUT_GET, 'user', FILTER_VALIDATE_INT);
    if ($targetId) {
        if (portfolio_user_is_of_type(array('student')) && $_SESSION['user']['gebruikersId'] == $targetId || portfolio_user_is_of_type(array('admin'))) {
            $usrData = portfolio_get_user_details($targetId);
            if ($usrData) {
                $msgData = portfolio_get_guestbook_messages($targetId);
                echo "<h2>Welkom " . $_SESSION['user']['voornaam'] . " " . $_SESSION['user']['achternaam'] . "</h2>";
                echo '<h2>Gastenboek van ' . $usrData['voornaam'] . ' ' . $usrData['achternaam'] . '</h2>';
                echo '<h3>Lijst berichten</h3>';
                if (count($msgData) > 0) {
                    echo '<table class="tableLeft">';
                    echo '<tr><th rel="col">naam</th><th rel="col">mail</th><th rel="col">bericht</th><th rel="col">verwijder</th></tr>';
                    foreach ($msgData as $msg) {
                        echo '<tr>' . '<td>' . $msg['zendernaam'] . '</td>' . '<td>' . $msg['email'] . '</td>' . '<td>' . $msg['bericht'] . '</td>' . '<td><a href="removeguestbook.php?message=' . $msg['berichtId'] . '" target="_blank">verwijder</a></td>' . '</tr>';
                    }
                    echo '</table>';
                } else {
                    echo '<p>Er zijn geen berichten gevonden</p>';
function portfolio_delete_mail_message($mailId)
{
    $link = portfolio_connect();
    if ($link) {
        $msgData = portfolio_get_message($mailId);
        if ($msgData) {
            if (portfolio_user_is_of_type(array('student', 'slb', 'docent')) && $_SESSION['user']['gebruikersId'] == $msgData['zenderId'] || portfolio_user_is_of_type(array('student', 'slb', 'docent')) && $_SESSION['user']['gebruikersId'] == $msgData['ontvangerId'] || portfolio_user_is_of_type(array('admin'))) {
                $sql = "DELETE FROM " . TABLE_MESSAGE . " \n\t\t\t\t\t\tWHERE berichtId=" . mysqli_real_escape_string($link, $mailId);
                return mysqli_query($link, $sql);
            } else {
                portfolio_set_error(PORTFOLIO_ERROR_UNAUTHORIZED);
            }
        } else {
            portfolio_set_error(PORTFOLIO_ERROR_NOT_FOUND);
        }
    }
    return null;
}