<?php
        if(isset($_POST['addhomework'])) {
            $classid = $_GET['id'];
            $addhwtitle = $_POST['addhwtitle'];
            $addhwdesc = $_POST['addhwdesc'];

            $pre = rand(1000, 5000);
            $target = "files/";
            $target = $target . $pre.basename( $_FILES['uploaded']['name']);

                if ($uploaded_size > 5242880)
                {
                    $problems[] = "<li>Your file is too large!</li>";
                }

                /* Let's assume the teachers won't upload a virus.
                if (($uploaded_type != "image/png") ||($uploaded_type != "image/jpeg") || ($uploaded_type != "image/gif"))
                {
                    $problems[] = "<li>Your profile picture has to be an image!</li>";
                }*/

                if (move_uploaded_file($_FILES['uploaded']['tmp_name'], $target)) {
                    $filename = $pre.basename( $_FILES['uploaded']['name']);
                }

                else {
                    $filename = NULL;
                }

            if ( empty($addhwtitle)) {
                $problems[] = "<li>You didn't put a homework title!</li>";
            }
            if ( empty($classid)) {
                $problems[] = "<li>A class isn't selected!</li>";
            }

            if ( empty($addhwdesc)) {
                $problems[] = "<li>You didn't put a homework assignment!</li>";
            }

            if( empty($problems)) {
                $query = $db->prepare("INSERT INTO assignments (course_id, title, description, filename) VALUES(?,?,?,?)");
                $pass = $query->execute(array($classid, $addhwtitle, $addhwdesc, $filename));

                echo "<div class='alert alert-success'>
                    <a class='close' data-dismiss='alert' href='#'>&times;</a>
                        <h4 class='alert-heading'>Success!</h4>
                        An assignment has been added to ". $classname ."
                </div>";
            }
            else {
                echo "<div class='alert alert-error'>
                    <a class='close' data-dismiss='alert' href='#'>&times;</a>
                        <h4 class='alert-heading'>Hold up!</h4>
                            <ul>";
                            foreach ($problems as $value) {
                                echo $value;
                            }
                echo "</ul></div>";
            }
        }
    ?>