/mod/assignment/lib.php

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<?PHP

// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * assignment_base is the base class for assignment types
 *
 * This class provides all the functionality for an assignment
 *
 * @package   mod-assignment
 * @copyright 1999 onwards Martin Dougiamas  {@link http://moodle.com}
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

/** Include eventslib.php */
require_once($CFG->libdir.'/eventslib.php');
/** Include formslib.php */
require_once($CFG->libdir.'/formslib.php');
/** Include calendar/lib.php */
require_once($CFG->dirroot.'/calendar/lib.php');

/** ASSIGNMENT_COUNT_WORDS = 1 */
define('ASSIGNMENT_COUNT_WORDS', 1);
/** ASSIGNMENT_COUNT_LETTERS = 2 */
define('ASSIGNMENT_COUNT_LETTERS', 2);

/**
 * Standard base class for all assignment submodules (assignment types).
 *
 * @package   mod-assignment
 * @copyright 1999 onwards Martin Dougiamas  {@link http://moodle.com}
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class assignment_base {

    const FILTER_ALL             = 0;
    const FILTER_SUBMITTED       = 1;
    const FILTER_REQUIRE_GRADING = 2;

    /** @var object */
    var $cm;
    /** @var object */
    var $course;
    /** @var stdClass */
    var $coursecontext;
    /** @var object */
    var $assignment;
    /** @var string */
    var $strassignment;
    /** @var string */
    var $strassignments;
    /** @var string */
    var $strsubmissions;
    /** @var string */
    var $strlastmodified;
    /** @var string */
    var $pagetitle;
    /**
     * @todo document this var
     */
    var $defaultformat;
    /**
     * @todo document this var
     */
    var $context;
    /** @var string */
    var $type;

    /**
     * Constructor for the base assignment class
     *
     * Constructor for the base assignment class.
     * If cmid is set create the cm, course, assignment objects.
     * If the assignment is hidden and the user is not a teacher then
     * this prints a page header and notice.
     *
     * @global object
     * @global object
     * @param int $cmid the current course module id - not set for new assignments
     * @param object $assignment usually null, but if we have it we pass it to save db access
     * @param object $cm usually null, but if we have it we pass it to save db access
     * @param object $course usually null, but if we have it we pass it to save db access
     */
    function assignment_base($cmid='staticonly', $assignment=NULL, $cm=NULL, $course=NULL) {
        global $COURSE, $DB;

        if ($cmid == 'staticonly') {
            //use static functions only!
            return;
        }

        global $CFG;

        if ($cm) {
            $this->cm = $cm;
        } else if (! $this->cm = get_coursemodule_from_id('assignment', $cmid)) {
            print_error('invalidcoursemodule');
        }

        $this->context = context_module::instance($this->cm->id);

        if ($course) {
            $this->course = $course;
        } else if ($this->cm->course == $COURSE->id) {
            $this->course = $COURSE;
        } else if (! $this->course = $DB->get_record('course', array('id'=>$this->cm->course))) {
            print_error('invalidid', 'assignment');
        }
        $this->coursecontext = context_course::instance($this->course->id);
        $courseshortname = format_text($this->course->shortname, true, array('context' => $this->coursecontext));

        if ($assignment) {
            $this->assignment = $assignment;
        } else if (! $this->assignment = $DB->get_record('assignment', array('id'=>$this->cm->instance))) {
            print_error('invalidid', 'assignment');
        }

        $this->assignment->cmidnumber = $this->cm->idnumber; // compatibility with modedit assignment obj
        $this->assignment->courseid   = $this->course->id; // compatibility with modedit assignment obj

        $this->strassignment = get_string('modulename', 'assignment');
        $this->strassignments = get_string('modulenameplural', 'assignment');
        $this->strsubmissions = get_string('submissions', 'assignment');
        $this->strlastmodified = get_string('lastmodified');
        $this->pagetitle = strip_tags($courseshortname.': '.$this->strassignment.': '.format_string($this->assignment->name, true, array('context' => $this->context)));

        // visibility handled by require_login() with $cm parameter
        // get current group only when really needed

    /// Set up things for a HTML editor if it's needed
        $this->defaultformat = editors_get_preferred_format();
    }

    /**
     * Display the assignment, used by view.php
     *
     * This in turn calls the methods producing individual parts of the page
     */
    function view() {

        $context = context_module::instance($this->cm->id);
        require_capability('mod/assignment:view', $context);

        add_to_log($this->course->id, "assignment", "view", "view.php?id={$this->cm->id}",
                   $this->assignment->id, $this->cm->id);

        $this->view_header();

        $this->view_intro();

        $this->view_dates();

        $this->view_feedback();

        $this->view_footer();
    }

    /**
     * Display the header and top of a page
     *
     * (this doesn't change much for assignment types)
     * This is used by the view() method to print the header of view.php but
     * it can be used on other pages in which case the string to denote the
     * page in the navigation trail should be passed as an argument
     *
     * @global object
     * @param string $subpage Description of subpage to be used in navigation trail
     */
    function view_header($subpage='') {
        global $CFG, $PAGE, $OUTPUT;

        if ($subpage) {
            $PAGE->navbar->add($subpage);
        }

        $PAGE->set_title($this->pagetitle);
        $PAGE->set_heading($this->course->fullname);

        echo $OUTPUT->header();

        groups_print_activity_menu($this->cm, $CFG->wwwroot . '/mod/assignment/view.php?id=' . $this->cm->id);

        echo '<div class="reportlink">'.$this->submittedlink().'</div>';
        echo '<div class="clearer"></div>';
        if (has_capability('moodle/site:config', context_system::instance())) {
            echo $OUTPUT->notification(get_string('upgradenotification', 'assignment'));
            $adminurl = new moodle_url('/admin/tool/assignmentupgrade/listnotupgraded.php');
            echo $OUTPUT->single_button($adminurl, get_string('viewassignmentupgradetool', 'assignment'));
        }
    }


    /**
     * Display the assignment intro
     *
     * This will most likely be extended by assignment type plug-ins
     * The default implementation prints the assignment description in a box
     */
    function view_intro() {
        global $OUTPUT;
        echo $OUTPUT->box_start('generalbox boxaligncenter', 'intro');
        echo format_module_intro('assignment', $this->assignment, $this->cm->id);
        echo $OUTPUT->box_end();
        echo plagiarism_print_disclosure($this->cm->id);
    }

    /**
     * Display the assignment dates
     *
     * Prints the assignment start and end dates in a box.
     * This will be suitable for most assignment types
     */
    function view_dates() {
        global $OUTPUT;
        if (!$this->assignment->timeavailable && !$this->assignment->timedue) {
            return;
        }

        echo $OUTPUT->box_start('generalbox boxaligncenter', 'dates');
        echo '<table>';
        if ($this->assignment->timeavailable) {
            echo '<tr><td class="c0">'.get_string('availabledate','assignment').':</td>';
            echo '    <td class="c1">'.userdate($this->assignment->timeavailable).'</td></tr>';
        }
        if ($this->assignment->timedue) {
            echo '<tr><td class="c0">'.get_string('duedate','assignment').':</td>';
            echo '    <td class="c1">'.userdate($this->assignment->timedue).'</td></tr>';
        }
        echo '</table>';
        echo $OUTPUT->box_end();
    }


    /**
     * Display the bottom and footer of a page
     *
     * This default method just prints the footer.
     * This will be suitable for most assignment types
     */
    function view_footer() {
        global $OUTPUT;
        echo $OUTPUT->footer();
    }

    /**
     * Display the feedback to the student
     *
     * This default method prints the teacher picture and name, date when marked,
     * grade and teacher submissioncomment.
     * If advanced grading is used the method render_grade from the
     * advanced grading controller is called to display the grade.
     *
     * @global object
     * @global object
     * @global object
     * @param object $submission The submission object or NULL in which case it will be loaded
     * @return bool
     */
    function view_feedback($submission=NULL) {
        global $USER, $CFG, $DB, $OUTPUT, $PAGE;
        require_once($CFG->libdir.'/gradelib.php');
        require_once("$CFG->dirroot/grade/grading/lib.php");

        if (!$submission) { /// Get submission for this assignment
            $userid = $USER->id;
            $submission = $this->get_submission($userid);
        } else {
            $userid = $submission->userid;
        }
        // Check the user can submit
        $canviewfeedback = ($userid == $USER->id && has_capability('mod/assignment:submit', $this->context, $USER->id, false));
        // If not then check if the user still has the view cap and has a previous submission
        $canviewfeedback = $canviewfeedback || (!empty($submission) && $submission->userid == $USER->id && has_capability('mod/assignment:view', $this->context));
        // Or if user can grade (is a teacher or admin)
        $canviewfeedback = $canviewfeedback || has_capability('mod/assignment:grade', $this->context);

        if (!$canviewfeedback) {
            // can not view or submit assignments -> no feedback
            return false;
        }

        $grading_info = grade_get_grades($this->course->id, 'mod', 'assignment', $this->assignment->id, $userid);
        $item = $grading_info->items[0];
        $grade = $item->grades[$userid];

        if ($grade->hidden or $grade->grade === false) { // hidden or error
            return false;
        }

        if ($grade->grade === null and empty($grade->str_feedback)) { // No grade to show yet
            // If sumbission then check if feedback is avaiable to show else return.
            if (!$submission) {
                return false;
            }

            $fs = get_file_storage();
            $noresponsefiles = $fs->is_area_empty($this->context->id, 'mod_assignment', 'response', $submission->id);
            if (empty($submission->submissioncomment) && $noresponsefiles) { // Nothing to show yet
                return false;
            }

            // We need the teacher info
            if (!$teacher = $DB->get_record('user', array('id'=>$submission->teacher))) {
                print_error('cannotfindteacher');
            }

            $feedbackdate = $submission->timemarked;
            $feedback = format_text($submission->submissioncomment, $submission->format);
            $strlonggrade = '-';
        }
        else {
            // We need the teacher info
            if (!$teacher = $DB->get_record('user', array('id'=>$grade->usermodified))) {
                print_error('cannotfindteacher');
            }

            $feedbackdate = $grade->dategraded;
            $feedback = $grade->str_feedback;
            $strlonggrade = $grade->str_long_grade;
        }

        // Print the feedback
        echo $OUTPUT->heading(get_string('submissionfeedback', 'assignment'), 3);

        echo '<table cellspacing="0" class="feedback">';

        echo '<tr>';
        echo '<td class="left picture">';
        if ($teacher) {
            echo $OUTPUT->user_picture($teacher);
        }
        echo '</td>';
        echo '<td class="topic">';
        echo '<div class="from">';
        if ($teacher) {
            echo '<div class="fullname">'.fullname($teacher).'</div>';
        }
        echo '<div class="time">'.userdate($feedbackdate).'</div>';
        echo '</div>';
        echo '</td>';
        echo '</tr>';

        echo '<tr>';
        echo '<td class="left side">&nbsp;</td>';
        echo '<td class="content">';

        if ($this->assignment->grade) {
            $gradestr = '<div class="grade">'. get_string("grade").': '.$strlonggrade. '</div>';
            if (!empty($submission) && $controller = get_grading_manager($this->context, 'mod_assignment', 'submission')->get_active_controller()) {
                $controller->set_grade_range(make_grades_menu($this->assignment->grade));
                echo $controller->render_grade($PAGE, $submission->id, $item, $gradestr, has_capability('mod/assignment:grade', $this->context));
            } else {
                echo $gradestr;
            }
            echo '<div class="clearer"></div>';
        }

        echo '<div class="comment">';
        echo $feedback;
        echo '</div>';
        echo '</tr>';
        if (method_exists($this, 'view_responsefile')) {
            $this->view_responsefile($submission);
        }
        echo '</table>';

        return true;
    }

    /**
     * Returns a link with info about the state of the assignment submissions
     *
     * This is used by view_header to put this link at the top right of the page.
     * For teachers it gives the number of submitted assignments with a link
     * For students it gives the time of their submission.
     * This will be suitable for most assignment types.
     *
     * @global object
     * @global object
     * @param bool $allgroup print all groups info if user can access all groups, suitable for index.php
     * @return string
     */
    function submittedlink($allgroups=false) {
        global $USER;
        global $CFG;

        $submitted = '';
        $urlbase = "{$CFG->wwwroot}/mod/assignment/";

        $context = context_module::instance($this->cm->id);
        if (has_capability('mod/assignment:grade', $context)) {
            if ($allgroups and has_capability('moodle/site:accessallgroups', $context)) {
                $group = 0;
            } else {
                $group = groups_get_activity_group($this->cm);
            }
            if ($this->type == 'offline') {
                $submitted = '<a href="'.$urlbase.'submissions.php?id='.$this->cm->id.'">'.
                             get_string('viewfeedback', 'assignment').'</a>';
            } else if ($count = $this->count_real_submissions($group)) {
                $submitted = '<a href="'.$urlbase.'submissions.php?id='.$this->cm->id.'">'.
                             get_string('viewsubmissions', 'assignment', $count).'</a>';
            } else {
                $submitted = '<a href="'.$urlbase.'submissions.php?id='.$this->cm->id.'">'.
                             get_string('noattempts', 'assignment').'</a>';
            }
        } else {
            if (isloggedin()) {
                if ($submission = $this->get_submission($USER->id)) {
                    // If the submission has been completed
                    if ($this->is_submitted_with_required_data($submission)) {
                        if ($submission->timemodified <= $this->assignment->timedue || empty($this->assignment->timedue)) {
                            $submitted = '<span class="early">'.userdate($submission->timemodified).'</span>';
                        } else {
                            $submitted = '<span class="late">'.userdate($submission->timemodified).'</span>';
                        }
                    }
                }
            }
        }

        return $submitted;
    }

    /**
     * Returns whether the assigment supports lateness information
     *
     * @return bool This assignment type supports lateness (true, default) or no (false)
     */
    function supports_lateness() {
        return true;
    }

    /**
     * @todo Document this function
     */
    function setup_elements(&$mform) {

    }

    /**
     * Any preprocessing needed for the settings form for
     * this assignment type
     *
     * @param array $default_values - array to fill in with the default values
     *      in the form 'formelement' => 'value'
     * @param object $form - the form that is to be displayed
     * @return none
     */
    function form_data_preprocessing(&$default_values, $form) {
    }

    /**
     * Any extra validation checks needed for the settings
     * form for this assignment type
     *
     * See lib/formslib.php, 'validation' function for details
     */
    function form_validation($data, $files) {
        return array();
    }

    /**
     * Create a new assignment activity
     *
     * Given an object containing all the necessary data,
     * (defined by the form in mod_form.php) this function
     * will create a new instance and return the id number
     * of the new instance.
     * The due data is added to the calendar
     * This is common to all assignment types.
     *
     * @global object
     * @global object
     * @param object $assignment The data from the form on mod_form.php
     * @return int The id of the assignment
     */
    function add_instance($assignment) {
        global $COURSE, $DB;

        $assignment->timemodified = time();
        $assignment->courseid = $assignment->course;

        $returnid = $DB->insert_record("assignment", $assignment);
        $assignment->id = $returnid;

        if ($assignment->timedue) {
            $event = new stdClass();
            $event->name        = $assignment->name;
            $event->description = format_module_intro('assignment', $assignment, $assignment->coursemodule);
            $event->courseid    = $assignment->course;
            $event->groupid     = 0;
            $event->userid      = 0;
            $event->modulename  = 'assignment';
            $event->instance    = $returnid;
            $event->eventtype   = 'due';
            $event->timestart   = $assignment->timedue;
            $event->timeduration = 0;

            calendar_event::create($event);
        }

        assignment_grade_item_update($assignment);

        return $returnid;
    }

    /**
     * Deletes an assignment activity
     *
     * Deletes all database records, files and calendar events for this assignment.
     *
     * @global object
     * @global object
     * @param object $assignment The assignment to be deleted
     * @return boolean False indicates error
     */
    function delete_instance($assignment) {
        global $CFG, $DB;

        $assignment->courseid = $assignment->course;

        $result = true;

        // now get rid of all files
        $fs = get_file_storage();
        if ($cm = get_coursemodule_from_instance('assignment', $assignment->id)) {
            $context = context_module::instance($cm->id);
            $fs->delete_area_files($context->id);
        }

        if (! $DB->delete_records('assignment_submissions', array('assignment'=>$assignment->id))) {
            $result = false;
        }

        if (! $DB->delete_records('event', array('modulename'=>'assignment', 'instance'=>$assignment->id))) {
            $result = false;
        }

        if (! $DB->delete_records('assignment', array('id'=>$assignment->id))) {
            $result = false;
        }
        $mod = $DB->get_field('modules','id',array('name'=>'assignment'));

        assignment_grade_item_delete($assignment);

        return $result;
    }

    /**
     * Updates a new assignment activity
     *
     * Given an object containing all the necessary data,
     * (defined by the form in mod_form.php) this function
     * will update the assignment instance and return the id number
     * The due date is updated in the calendar
     * This is common to all assignment types.
     *
     * @global object
     * @global object
     * @param object $assignment The data from the form on mod_form.php
     * @return bool success
     */
    function update_instance($assignment) {
        global $COURSE, $DB;

        $assignment->timemodified = time();

        $assignment->id = $assignment->instance;
        $assignment->courseid = $assignment->course;

        $DB->update_record('assignment', $assignment);

        if ($assignment->timedue) {
            $event = new stdClass();

            if ($event->id = $DB->get_field('event', 'id', array('modulename'=>'assignment', 'instance'=>$assignment->id))) {

                $event->name        = $assignment->name;
                $event->description = format_module_intro('assignment', $assignment, $assignment->coursemodule);
                $event->timestart   = $assignment->timedue;

                $calendarevent = calendar_event::load($event->id);
                $calendarevent->update($event);
            } else {
                $event = new stdClass();
                $event->name        = $assignment->name;
                $event->description = format_module_intro('assignment', $assignment, $assignment->coursemodule);
                $event->courseid    = $assignment->course;
                $event->groupid     = 0;
                $event->userid      = 0;
                $event->modulename  = 'assignment';
                $event->instance    = $assignment->id;
                $event->eventtype   = 'due';
                $event->timestart   = $assignment->timedue;
                $event->timeduration = 0;

                calendar_event::create($event);
            }
        } else {
            $DB->delete_records('event', array('modulename'=>'assignment', 'instance'=>$assignment->id));
        }

        // get existing grade item
        assignment_grade_item_update($assignment);

        return true;
    }

    /**
     * Update grade item for this submission.
     *
     * @param stdClass $submission The submission instance
     */
    function update_grade($submission) {
        assignment_update_grades($this->assignment, $submission->userid);
    }

    /**
     * Top-level function for handling of submissions called by submissions.php
     *
     * This is for handling the teacher interaction with the grading interface
     * This should be suitable for most assignment types.
     *
     * @global object
     * @param string $mode Specifies the kind of teacher interaction taking place
     */
    function submissions($mode) {
        ///The main switch is changed to facilitate
        ///1) Batch fast grading
        ///2) Skip to the next one on the popup
        ///3) Save and Skip to the next one on the popup

        //make user global so we can use the id
        global $USER, $OUTPUT, $DB, $PAGE;

        $mailinfo = optional_param('mailinfo', null, PARAM_BOOL);

        if (optional_param('next', null, PARAM_BOOL)) {
            $mode='next';
        }
        if (optional_param('saveandnext', null, PARAM_BOOL)) {
            $mode='saveandnext';
        }

        if (is_null($mailinfo)) {
            if (optional_param('sesskey', null, PARAM_BOOL)) {
                set_user_preference('assignment_mailinfo', 0);
            } else {
                $mailinfo = get_user_preferences('assignment_mailinfo', 0);
            }
        } else {
            set_user_preference('assignment_mailinfo', $mailinfo);
        }

        if (!($this->validate_and_preprocess_feedback())) {
            // form was submitted ('Save' or 'Save and next' was pressed, but validation failed)
            $this->display_submission();
            return;
        }

        switch ($mode) {
            case 'grade':                         // We are in a main window grading
                if ($submission = $this->process_feedback()) {
                    $this->display_submissions(get_string('changessaved'));
                } else {
                    $this->display_submissions();
                }
                break;

            case 'single':                        // We are in a main window displaying one submission
                if ($submission = $this->process_feedback()) {
                    $this->display_submissions(get_string('changessaved'));
                } else {
                    $this->display_submission();
                }
                break;

            case 'all':                          // Main window, display everything
                $this->display_submissions();
                break;

            case 'fastgrade':
                ///do the fast grading stuff  - this process should work for all 3 subclasses
                $grading    = false;
                $commenting = false;
                $col        = false;
                if (isset($_POST['submissioncomment'])) {
                    $col = 'submissioncomment';
                    $commenting = true;
                }
                if (isset($_POST['menu'])) {
                    $col = 'menu';
                    $grading = true;
                }
                if (!$col) {
                    //both submissioncomment and grade columns collapsed..
                    $this->display_submissions();
                    break;
                }

                foreach ($_POST[$col] as $id => $unusedvalue){

                    $id = (int)$id; //clean parameter name

                    $this->process_outcomes($id);

                    if (!$submission = $this->get_submission($id)) {
                        $submission = $this->prepare_new_submission($id);
                        $newsubmission = true;
                    } else {
                        $newsubmission = false;
                    }
                    unset($submission->data1);  // Don't need to update this.
                    unset($submission->data2);  // Don't need to update this.

                    //for fast grade, we need to check if any changes take place
                    $updatedb = false;

                    if ($grading) {
                        $grade = $_POST['menu'][$id];
                        $updatedb = $updatedb || ($submission->grade != $grade);
                        $submission->grade = $grade;
                    } else {
                        if (!$newsubmission) {
                            unset($submission->grade);  // Don't need to update this.
                        }
                    }
                    if ($commenting) {
                        $commentvalue = trim($_POST['submissioncomment'][$id]);
                        $updatedb = $updatedb || ($submission->submissioncomment != $commentvalue);
                        $submission->submissioncomment = $commentvalue;
                    } else {
                        unset($submission->submissioncomment);  // Don't need to update this.
                    }

                    $submission->teacher    = $USER->id;
                    if ($updatedb) {
                        $submission->mailed = (int)(!$mailinfo);
                    }

                    $submission->timemarked = time();

                    //if it is not an update, we don't change the last modified time etc.
                    //this will also not write into database if no submissioncomment and grade is entered.

                    if ($updatedb){
                        if ($newsubmission) {
                            if (!isset($submission->submissioncomment)) {
                                $submission->submissioncomment = '';
                            }
                            $sid = $DB->insert_record('assignment_submissions', $submission);
                            $submission->id = $sid;
                        } else {
                            $DB->update_record('assignment_submissions', $submission);
                        }

                        // trigger grade event
                        $this->update_grade($submission);

                        //add to log only if updating
                        add_to_log($this->course->id, 'assignment', 'update grades',
                                   'submissions.php?id='.$this->cm->id.'&user='.$submission->userid,
                                   $submission->userid, $this->cm->id);
                    }

                }

                $message = $OUTPUT->notification(get_string('changessaved'), 'notifysuccess');

                $this->display_submissions($message);
                break;


            case 'saveandnext':
                ///We are in pop up. save the current one and go to the next one.
                //first we save the current changes
                if ($submission = $this->process_feedback()) {
                    //print_heading(get_string('changessaved'));
                    //$extra_javascript = $this->update_main_listing($submission);
                }

            case 'next':
                /// We are currently in pop up, but we want to skip to next one without saving.
                ///    This turns out to be similar to a single case
                /// The URL used is for the next submission.
                $offset = required_param('offset', PARAM_INT);
                $nextid = required_param('nextid', PARAM_INT);
                $id = required_param('id', PARAM_INT);
                $filter = optional_param('filter', self::FILTER_ALL, PARAM_INT);

                if ($mode == 'next' || $filter !== self::FILTER_REQUIRE_GRADING) {
                    $offset = (int)$offset+1;
                }
                $redirect = new moodle_url('submissions.php',
                        array('id' => $id, 'offset' => $offset, 'userid' => $nextid,
                        'mode' => 'single', 'filter' => $filter));

                redirect($redirect);
                break;

            case 'singlenosave':
                $this->display_submission();
                break;

            default:
                echo "something seriously is wrong!!";
                break;
        }
    }

    /**
     * Checks if grading method allows quickgrade mode. At the moment it is hardcoded
     * that advanced grading methods do not allow quickgrade.
     *
     * Assignment type plugins are not allowed to override this method
     *
     * @return boolean
     */
    public final function quickgrade_mode_allowed() {
        global $CFG;
        require_once("$CFG->dirroot/grade/grading/lib.php");
        if ($controller = get_grading_manager($this->context, 'mod_assignment', 'submission')->get_active_controller()) {
            return false;
        }
        return true;
    }

    /**
     * Helper method updating the listing on the main script from popup using javascript
     *
     * @global object
     * @global object
     * @param $submission object The submission whose data is to be updated on the main page
     */
    function update_main_listing($submission) {
        global $SESSION, $CFG, $OUTPUT;

        $output = '';

        $perpage = get_user_preferences('assignment_perpage', 10);

        $quickgrade = get_user_preferences('assignment_quickgrade', 0) && $this->quickgrade_mode_allowed();

        /// Run some Javascript to try and update the parent page
        $output .= '<script type="text/javascript">'."\n<!--\n";
        if (empty($SESSION->flextable['mod-assignment-submissions']->collapse['submissioncomment'])) {
            if ($quickgrade){
                $output.= 'opener.document.getElementById("submissioncomment'.$submission->userid.'").value="'
                .trim($submission->submissioncomment).'";'."\n";
             } else {
                $output.= 'opener.document.getElementById("com'.$submission->userid.
                '").innerHTML="'.shorten_text(trim(strip_tags($submission->submissioncomment)), 15)."\";\n";
            }
        }

        if (empty($SESSION->flextable['mod-assignment-submissions']->collapse['grade'])) {
            //echo optional_param('menuindex');
            if ($quickgrade){
                $output.= 'opener.document.getElementById("menumenu'.$submission->userid.
                '").selectedIndex="'.optional_param('menuindex', 0, PARAM_INT).'";'."\n";
            } else {
                $output.= 'opener.document.getElementById("g'.$submission->userid.'").innerHTML="'.
                $this->display_grade($submission->grade)."\";\n";
            }
        }
        //need to add student's assignments in there too.
        if (empty($SESSION->flextable['mod-assignment-submissions']->collapse['timemodified']) &&
            $submission->timemodified) {
            $output.= 'opener.document.getElementById("ts'.$submission->userid.
                 '").innerHTML="'.addslashes_js($this->print_student_answer($submission->userid)).userdate($submission->timemodified)."\";\n";
        }

        if (empty($SESSION->flextable['mod-assignment-submissions']->collapse['timemarked']) &&
            $submission->timemarked) {
            $output.= 'opener.document.getElementById("tt'.$submission->userid.
                 '").innerHTML="'.userdate($submission->timemarked)."\";\n";
        }

        if (empty($SESSION->flextable['mod-assignment-submissions']->collapse['status'])) {
            $output.= 'opener.document.getElementById("up'.$submission->userid.'").className="s1";';
            $buttontext = get_string('update');
            $url = new moodle_url('/mod/assignment/submissions.php', array(
                    'id' => $this->cm->id,
                    'userid' => $submission->userid,
                    'mode' => 'single',
                    'offset' => (optional_param('offset', '', PARAM_INT)-1)));
            $button = $OUTPUT->action_link($url, $buttontext, new popup_action('click', $url, 'grade'.$submission->userid, array('height' => 450, 'width' => 700)), array('ttile'=>$buttontext));

            $output .= 'opener.document.getElementById("up'.$submission->userid.'").innerHTML="'.addslashes_js($button).'";';
        }

        $grading_info = grade_get_grades($this->course->id, 'mod', 'assignment', $this->assignment->id, $submission->userid);

        if (empty($SESSION->flextable['mod-assignment-submissions']->collapse['finalgrade'])) {
            $output.= 'opener.document.getElementById("finalgrade_'.$submission->userid.
            '").innerHTML="'.$grading_info->items[0]->grades[$submission->userid]->str_grade.'";'."\n";
        }

        if (!empty($CFG->enableoutcomes) and empty($SESSION->flextable['mod-assignment-submissions']->collapse['outcome'])) {

            if (!empty($grading_info->outcomes)) {
                foreach($grading_info->outcomes as $n=>$outcome) {
                    if ($outcome->grades[$submission->userid]->locked) {
                        continue;
                    }

                    if ($quickgrade){
                        $output.= 'opener.document.getElementById("outcome_'.$n.'_'.$submission->userid.
                        '").selectedIndex="'.$outcome->grades[$submission->userid]->grade.'";'."\n";

                    } else {
                        $options = make_grades_menu(-$outcome->scaleid);
                        $options[0] = get_string('nooutcome', 'grades');
                        $output.= 'opener.document.getElementById("outcome_'.$n.'_'.$submission->userid.'").innerHTML="'.$options[$outcome->grades[$submission->userid]->grade]."\";\n";
                    }

                }
            }
        }

        $output .= "\n-->\n</script>";
        return $output;
    }

    /**
     *  Return a grade in user-friendly form, whether it's a scale or not
     *
     * @global object
     * @param mixed $grade
     * @return string User-friendly representation of grade
     */
    function display_grade($grade) {
        global $DB;

        static $scalegrades = array();   // Cache scales for each assignment - they might have different scales!!

        if ($this->assignment->grade >= 0) {    // Normal number
            if ($grade == -1) {
                return '-';
            } else {
                return $grade.' / '.$this->assignment->grade;
            }

        } else {                                // Scale
            if (empty($scalegrades[$this->assignment->id])) {
                if ($scale = $DB->get_record('scale', array('id'=>-($this->assignment->grade)))) {
                    $scalegrades[$this->assignment->id] = make_menu_from_list($scale->scale);
                } else {
                    return '-';
                }
            }
            if (isset($scalegrades[$this->assignment->id][$grade])) {
                return $scalegrades[$this->assignment->id][$grade];
            }
            return '-';
        }
    }

    /**
     *  Display a single submission, ready for grading on a popup window
     *
     * This default method prints the teacher info and submissioncomment box at the top and
     * the student info and submission at the bottom.
     * This method also fetches the necessary data in order to be able to
     * provide a "Next submission" button.
     * Calls preprocess_submission() to give assignment type plug-ins a chance
     * to process submissions before they are graded
     * This method gets its arguments from the page parameters userid and offset
     *
     * @global object
     * @global object
     * @param string $extra_javascript
     */
    function display_submission($offset=-1,$userid =-1, $display=true) {
        global $CFG, $DB, $PAGE, $OUTPUT, $USER;
        require_once($CFG->libdir.'/gradelib.php');
        require_once($CFG->libdir.'/tablelib.php');
        require_once("$CFG->dirroot/repository/lib.php");
        require_once("$CFG->dirroot/grade/grading/lib.php");
        if ($userid==-1) {
            $userid = required_param('userid', PARAM_INT);
        }
        if ($offset==-1) {
            $offset = required_param('offset', PARAM_INT);//offset for where to start looking for student.
        }
        $filter = optional_param('filter', 0, PARAM_INT);

        if (!$user = $DB->get_record('user', array('id'=>$userid))) {
            print_error('nousers');
        }

        if (!$submission = $this->get_submission($user->id)) {
            $submission = $this->prepare_new_submission($userid);
        }
        if ($submission->timemodified > $submission->timemarked) {
            $subtype = 'assignmentnew';
        } else {
            $subtype = 'assignmentold';
        }

        $grading_info = grade_get_grades($this->course->id, 'mod', 'assignment', $this->assignment->id, array($user->id));
        $gradingdisabled = $grading_info->items[0]->grades[$userid]->locked || $grading_info->items[0]->grades[$userid]->overridden;

    /// construct SQL, using current offset to find the data of the next student
        $course     = $this->course;
        $assignment = $this->assignment;
        $cm         = $this->cm;
        $context    = context_module::instance($cm->id);

        //reset filter to all for offline assignment
        if ($assignment->assignmenttype == 'offline' && $filter == self::FILTER_SUBMITTED) {
            $filter = self::FILTER_ALL;
        }
        /// Get all ppl that can submit assignments

        $currentgroup = groups_get_activity_group($cm);
        $users = get_enrolled_users($context, 'mod/assignment:submit', $currentgroup, 'u.id');
        if ($users) {
            $users = array_keys($users);
            // if groupmembersonly used, remove users who are not in any group
            if (!empty($CFG->enablegroupmembersonly) and $cm->groupmembersonly) {
                if ($groupingusers = groups_get_grouping_members($cm->groupingid, 'u.id', 'u.id')) {
                    $users = array_intersect($users, array_keys($groupingusers));
                }
            }
        }

        $nextid = 0;
        $where = '';
        if($filter == self::FILTER_SUBMITTED) {
            $where .= 's.timemodified > 0 AND ';
        } else if($filter == self::FILTER_REQUIRE_GRADING) {
            $where .= 's.timemarked < s.timemodified AND ';
        }

        if ($users) {
            $userfields = user_picture::fields('u', array('lastaccess'));
            $select = "SELECT $userfields,
                              s.id AS submissionid, s.grade, s.submissioncomment,
                              s.timemodified, s.timemarked,
                              CASE WHEN s.timemarked > 0 AND s.timemarked >= s.timemodified THEN 1
                                   ELSE 0 END AS status ";

            $sql = 'FROM {user} u '.
                   'LEFT JOIN {assignment_submissions} s ON u.id = s.userid
                   AND s.assignment = '.$this->assignment->id.' '.
                   'WHERE '.$where.'u.id IN ('.implode(',', $users).') ';

            if ($sort = flexible_table::get_sort_for_table('mod-assignment-submissions')) {
                $sort = 'ORDER BY '.$sort.' ';
            }
            $auser = $DB->get_records_sql($select.$sql.$sort, null, $offset, 2);

            if (is_array($auser) && count($auser)>1) {
                $nextuser = next($auser);
                $nextid = $nextuser->id;
            }
        }

        if ($submission->teacher) {
            $teacher = $DB->get_record('user', array('id'=>$submission->teacher));
        } else {
            global $USER;
            $teacher = $USER;
        }

        $this->preprocess_submission($submission);

        $mformdata = new stdClass();
        $mformdata->context = $this->context;
        $mformdata->maxbytes = $this->course->maxbytes;
        $mformdata->courseid = $this->course->id;
        $mformdata->teacher = $teacher;
        $mformdata->assignment = $assignment;
        $mformdata->submission = $submission;
        $mformdata->lateness = $this->display_lateness($submission->timemodified);
        $mformdata->auser = $auser;
        $mformdata->user = $user;
        $mformdata->offset = $offset;
        $mformdata->userid = $userid;
        $mformdata->cm = $this->cm;
        $mformdata->grading_info = $grading_info;
        $mformdata->enableoutcomes = $CFG->enableoutcomes;
        $mformdata->grade = $this->assignment->grade;
        $mformdata->gradingdisabled = $gradingdisabled;
        $mformdata->nextid = $nextid;
        $mformdata->submissioncomment= $submission->submissioncomment;
        $mformdata->submissioncommentformat= FORMAT_HTML;
        $mformdata->submission_content= $this->print_user_files($user->id,true);
        $mformdata->filter = $filter;
        $mformdata->mailinfo = get_user_preferences('assignment_mailinfo', 0);
         if ($assignment->assignmenttype == 'upload') {
            $mformdata->fileui_options = array('subdirs'=>1, 'maxbytes'=>$assignment->maxbytes, 'maxfiles'=>$assignment->var1, 'accepted_types'=>'*', 'return_types'=>FILE_INTERNAL);
        } elseif ($assignment->assignmenttype == 'uploadsingle') {
            $mformdata->fileui_options = array('subdirs'=>0, 'maxbytes'=>$CFG->userquota, 'maxfiles'=>1, 'accepted_types'=>'*', 'return_types'=>FILE_INTERNAL);
        }
        $advancedgradingwarning = false;
        $gradingmanager = get_grading_manager($this->context, 'mod_assignment', 'submission');
        if ($gradingmethod = $gradingmanager->get_active_method()) {
            $controller = $gradingmanager->get_controller($gradingmethod);
            if ($controller->is_form_available()) {
                $itemid = null;
                if (!empty($submission->id)) {
                    $itemid = $submission->id;
                }
                if ($gradingdisabled && $itemid) {
                    $mformdata->advancedgradinginstance = $controller->get_current_instance($USER->id, $itemid);
                } else if (!$gradingdisabled) {
                    $instanceid = optional_param('advancedgradinginstanceid', 0, PARAM_INT);
                    $mformdata->advancedgradinginstance = $controller->get_or_create_instance($instanceid, $USER->id, $itemid);
                }
            } else {
                $advancedgradingwarning = $controller->form_unavailable_notification();
            }
        }

        $submitform = new assignment_grading_form( null, $mformdata );

         if (!$display) {
            $ret_data = new stdClass();
            $ret_data->mform = $submitform;
            if (isset($mformdata->fileui_options)) {
                $ret_data->fileui_options = $mformdata->fileui_options;
            }
            return $ret_data;
        }

        if ($submitform->is_cancelled()) {
            redirect('submissions.php?id='.$this->cm->id);
        }

        $submitform->set_data($mformdata);

        $PAGE->set_title($this->course->fullname . ': ' .get_string('feedback', 'assignment').' - '.fullname($user, true));
        $PAGE->set_heading($this->course->fullname);
        $PAGE->navbar->add(get_string('submissions', 'assignment'), new moodle_url('/mod/assignment/submissions.php', array('id'=>$cm->id)));
        $PAGE->navbar->add(fullname($user, true));

        echo $OUTPUT->header();
        echo $OUTPUT->heading(get_string('feedback', 'assignment').': '.fullname($user, true));

        // display mform here...
        if ($advancedgradingwarning) {
            echo $OUTPUT->notification($advancedgradingwarning, 'error');
        }
        $submitform->display();

        $customfeedback = $this->custom_feedbackform($submission, true);
        if (!empty($customfeedback)) {
            echo $customfeedback;
        }

        echo $OUTPUT->footer();
    }

    /**
     *  Preprocess submission before grading
     *
     * Called by display_submission()
     * The default type does nothing here.
     *
     * @param object $submission The submission object
     */
    function preprocess_submission(&$submission) {
    }

    /**
     *  Display all the submissions ready for grading
     *
     * @global object
     * @global object
     * @global object
     * @global object
     * @param string $message
     * @return bool|void
     */
    function display_submissions($message='') {
        global $CFG, $DB, $USER, $DB, $OUTPUT, $PAGE;
        require_once($CFG->libdir.'/gradelib.php');

        /* first we check to see if the form has just been submitted
         * to request user_preference updates
         */

       $filters = array(self::FILTER_ALL             => get_string('all'),
                        self::FILTER_REQUIRE_GRADING => get_string('requiregrading', 'assignment'));

        $updatepref = optional_param('updatepref', 0, PARAM_BOOL);
        if ($updatepref) {
            $perpage = optional_param('perpage', 10, PARAM_INT);
            $perpage = ($perpage <= 0) ? 10 : $perpage ;
            $filter = optional_param('filter', 0, PARAM_INT);
            set_user_preference('assignment_perpage', $perpage);
            set_user_preference('assignment_quickgrade', optional_param('quickgrade', 0, PARAM_BOOL));
            set_user_preference('assignment_filter', $filter);
        }

        /* next we get perpage and quickgrade (allow quick grade) params
         * from database
         */
        $perpage    = get_user_preferences('assignment_perpage', 10);
        $quickgrade = get_user_preferences('assignment_quickgrade', 0) && $this->quickgrade_mode_allowed();
        $filter = get_user_preferences('assignment_filter', 0);
        $grading_info = grade_get_grades($this->course->id, 'mod', 'assignment', $this->assignment->id);

        if (!empty($CFG->enableoutcomes) and !empty($grading_info->outcomes)) {
            $uses_outcomes = true;
        } else {
            $uses_outcomes = false;
        }

        $page    = optional_param('page', 0, PARAM_INT);
        $strsaveallfeedback = get_string('saveallfeedback', 'assignment');

    /// Some shortcuts to make the code read better

        $course     = $this->course;
        $assignment = $this->assignment;
        $cm         = $this->cm;
        $hassubmission = false;

        // reset filter to all for offline assignment only.
        if ($assignment->assignmenttype == 'offline') {
            if ($filter == self::FILTER_SUBMITTED) {
                $filter = self::FILTER_ALL;
            }
        } else {
            $filters[self::FILTER_SUBMITTED] = get_string('submitted', 'assignment');
        }

        $tabindex = 1; //tabindex for quick grading tabbing; Not working for dropdowns yet
        add_to_log($course->id, 'assignment', 'view submission', 'submissions.php?id='.$this->cm->id, $this->assignment->id, $this->cm->id);

        $PAGE->set_title($this->assignment->name);
        $PAGE->set_heading($this->course->fullname);
        echo $OUTPUT->header();

        echo '<div class="usersubmissions">';

        //hook to allow plagiarism plugins to update status/print links.
        echo plagiarism_update_status($this->course, $this->cm);

        $course_context = context_course::instance($course->id);
        if (has_capability('gradereport/grader:view', $course_context) && has_capability('moodle/grade:viewall', $course_context)) {
            echo '<div class="allcoursegrades"><a href="' . $CFG->wwwroot . '/grade/report/grader/index.php?id=' . $course->id . '">'
                . get_string('seeallcoursegrades', 'grades') . '</a></div>';
        }

        if (!empty($message)) {
            echo $message;   // display m…