Proyectos de Subversion Moodle

<?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/>.

/**

 * Library of functions for the quiz module.

 *

 * This contains functions that are called also from outside the quiz module

 * Functions that are only called by the quiz module itself are in {@link locallib.php}

 *

 * @package    mod_quiz

 * @copyright  1999 onwards Martin Dougiamas {@link http://moodle.com}

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

use qbank_managecategories\helper;

defined('MOODLE_INTERNAL') || die();

use mod_quiz\access_manager;

use mod_quiz\grade_calculator;

use mod_quiz\question\bank\custom_view;

use mod_quiz\question\bank\qbank_helper;

use mod_quiz\question\display_options;

use mod_quiz\question\qubaids_for_quiz;

use mod_quiz\question\qubaids_for_users_attempts;

use core_question\statistics\questions\all_calculated_for_qubaid_condition;

use mod_quiz\local\override_cache;

use mod_quiz\quiz_attempt;

use mod_quiz\quiz_settings;

require_once($CFG->dirroot . '/calendar/lib.php');

require_once($CFG->dirroot . '/question/editlib.php');

/**#@+

 * Option controlling what options are offered on the quiz settings form.

 */

define('QUIZ_MAX_ATTEMPT_OPTION', 10);

define('QUIZ_MAX_QPP_OPTION', 50);

define('QUIZ_MAX_DECIMAL_OPTION', 5);

define('QUIZ_MAX_Q_DECIMAL_OPTION', 7);

/**#@-*/

/**#@+

 * Options determining how the grades from individual attempts are combined to give

 * the overall grade for a user

 */

define('QUIZ_GRADEHIGHEST', '1');

define('QUIZ_GRADEAVERAGE', '2');

define('QUIZ_ATTEMPTFIRST', '3');

define('QUIZ_ATTEMPTLAST',  '4');

/**#@-*/

/**

 * @var int If start and end date for the quiz are more than this many seconds apart

 * they will be represented by two separate events in the calendar

 */

define('QUIZ_MAX_EVENT_LENGTH', 5*24*60*60); // 5 days.

/**#@+

 * Options for navigation method within quizzes.

 */

define('QUIZ_NAVMETHOD_FREE', 'free');

define('QUIZ_NAVMETHOD_SEQ',  'sequential');

/**#@-*/

/**

 * Event types.

 */

define('QUIZ_EVENT_TYPE_OPEN', 'open');

define('QUIZ_EVENT_TYPE_CLOSE', 'close');

require_once(__DIR__ . '/deprecatedlib.php');

/**

 * 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.

 *

 * @param stdClass $quiz the data that came from the form.

 * @return mixed the id of the new instance on success,

 *          false or a string error message on failure.

 */

function quiz_add_instance($quiz) {

    global $DB;

    $cmid = $quiz->coursemodule;

    // Process the options from the form.

    $quiz->timecreated = time();

    $result = quiz_process_options($quiz);

    if ($result && is_string($result)) {

        return $result;

    }

    // Try to store it in the database.

    $quiz->id = $DB->insert_record('quiz', $quiz);

    // Create the first section for this quiz.

    $DB->insert_record('quiz_sections', ['quizid' => $quiz->id,

            'firstslot' => 1, 'heading' => '', 'shufflequestions' => 0]);

    // Do the processing required after an add or an update.

    quiz_after_add_or_update($quiz);

    return $quiz->id;

}

/**

 * Given an object containing all the necessary data,

 * (defined by the form in mod_form.php) this function

 * will update an existing instance with new data.

 *

 * @param stdClass $quiz the data that came from the form.

 * @param stdClass $mform no longer used.

 * @return mixed true on success, false or a string error message on failure.

 */

function quiz_update_instance($quiz, $mform) {

    global $CFG, $DB;

    require_once($CFG->dirroot . '/mod/quiz/locallib.php');

    // Process the options from the form.

    $result = quiz_process_options($quiz);

    if ($result && is_string($result)) {

        return $result;

    }

    // Get the current value, so we can see what changed.

    $oldquiz = $DB->get_record('quiz', ['id' => $quiz->instance]);

    // We need two values from the existing DB record that are not in the form,

    // in some of the function calls below.

    $quiz->sumgrades = $oldquiz->sumgrades;

    $quiz->grade     = $oldquiz->grade;

    // Update the database.

    $quiz->id = $quiz->instance;

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

    // Do the processing required after an add or an update.

    quiz_after_add_or_update($quiz);

    if ($oldquiz->grademethod != $quiz->grademethod) {

        $gradecalculator = quiz_settings::create($quiz->id)->get_grade_calculator();

        $gradecalculator->recompute_all_final_grades();

        quiz_update_grades($quiz);

    }

    $quizdateschanged = $oldquiz->timelimit   != $quiz->timelimit

                     || $oldquiz->timeclose   != $quiz->timeclose

                     || $oldquiz->graceperiod != $quiz->graceperiod;

    if ($quizdateschanged) {

        quiz_update_open_attempts(['quizid' => $quiz->id]);

    }

    // Delete any previous preview attempts.

    quiz_delete_previews($quiz);

    // Repaginate, if asked to.

    if (!empty($quiz->repaginatenow) && !quiz_has_attempts($quiz->id)) {

        quiz_repaginate_questions($quiz->id, $quiz->questionsperpage);

    }

    return true;

}

/**

 * Given an ID of an instance of this module,

 * this function will permanently delete the instance

 * and any data that depends on it.

 *

 * @param int $id the id of the quiz to delete.

 * @return bool success or failure.

 */

function quiz_delete_instance($id) {

    global $DB;

    $quiz = $DB->get_record('quiz', ['id' => $id], '*', MUST_EXIST);

    quiz_delete_all_attempts($quiz);

    // Delete all overrides, and for performance do not log or check permissions.

    $quizobj = quiz_settings::create($quiz->id);

    $quizobj->get_override_manager()->delete_all_overrides(shouldlog: false);

    quiz_delete_references($quiz->id);

    // We need to do the following deletes before we try and delete randoms, otherwise they would still be 'in use'.

    $DB->delete_records('quiz_slots', ['quizid' => $quiz->id]);

    $DB->delete_records('quiz_sections', ['quizid' => $quiz->id]);

    $DB->delete_records('quiz_feedback', ['quizid' => $quiz->id]);

    access_manager::delete_settings($quiz);

    $events = $DB->get_records('event', ['modulename' => 'quiz', 'instance' => $quiz->id]);

    foreach ($events as $event) {

        $event = calendar_event::load($event);

        $event->delete();

    }

    quiz_grade_item_delete($quiz);

    // We must delete the module record after we delete the grade item.

    $DB->delete_records('quiz', ['id' => $quiz->id]);

    return true;

}

/**

 * Updates a quiz object with override information for a user.

 *

 * Algorithm:  For each quiz setting, if there is a matching user-specific override,

 *   then use that otherwise, if there are group-specific overrides, return the most

 *   lenient combination of them.  If neither applies, leave the quiz setting unchanged.

 *

 *   Special case: if there is more than one password that applies to the user, then

 *   quiz->extrapasswords will contain an array of strings giving the remaining

 *   passwords.

 *

 * @param stdClass $quiz The quiz object.

 * @param int $userid The userid.

 * @return stdClass $quiz The updated quiz object.

 */

function quiz_update_effective_access($quiz, $userid) {

    global $DB;

    // Check for user override.

    $override = $DB->get_record('quiz_overrides', ['quiz' => $quiz->id, 'userid' => $userid]);

    if (!$override) {

        $override = new stdClass();

        $override->timeopen = null;

        $override->timeclose = null;

        $override->timelimit = null;

        $override->attempts = null;

        $override->password = null;

    }

    // Check for group overrides.

    $groupings = groups_get_user_groups($quiz->course, $userid);

    if (!empty($groupings[0])) {

        // Select all overrides that apply to the User's groups.

        list($extra, $params) = $DB->get_in_or_equal(array_values($groupings[0]));

        $sql = "SELECT * FROM {quiz_overrides}

                WHERE groupid $extra AND quiz = ?";

        $params[] = $quiz->id;

        $records = $DB->get_records_sql($sql, $params);

        // Combine the overrides.

        $opens = [];

        $closes = [];

        $limits = [];

        $attempts = [];

        $passwords = [];

        foreach ($records as $gpoverride) {

            if (isset($gpoverride->timeopen)) {

                $opens[] = $gpoverride->timeopen;

            }

            if (isset($gpoverride->timeclose)) {

                $closes[] = $gpoverride->timeclose;

            }

            if (isset($gpoverride->timelimit)) {

                $limits[] = $gpoverride->timelimit;

            }

            if (isset($gpoverride->attempts)) {

                $attempts[] = $gpoverride->attempts;

            }

            if (isset($gpoverride->password)) {

                $passwords[] = $gpoverride->password;

            }

        }

        // If there is a user override for a setting, ignore the group override.

        if (is_null($override->timeopen) && count($opens)) {

            $override->timeopen = min($opens);

        }

        if (is_null($override->timeclose) && count($closes)) {

            if (in_array(0, $closes)) {

                $override->timeclose = 0;

            } else {

                $override->timeclose = max($closes);

            }

        }

        if (is_null($override->timelimit) && count($limits)) {

            if (in_array(0, $limits)) {

                $override->timelimit = 0;

            } else {

                $override->timelimit = max($limits);

            }

        }

        if (is_null($override->attempts) && count($attempts)) {

            if (in_array(0, $attempts)) {

                $override->attempts = 0;

            } else {

                $override->attempts = max($attempts);

            }

        }

        if (is_null($override->password) && count($passwords)) {

            $override->password = array_shift($passwords);

            if (count($passwords)) {

                $override->extrapasswords = $passwords;

            }

        }

    }

    // Merge with quiz defaults.

    $keys = ['timeopen', 'timeclose', 'timelimit', 'attempts', 'password', 'extrapasswords'];

    foreach ($keys as $key) {

        if (isset($override->{$key})) {

            $quiz->{$key} = $override->{$key};

        }

    }

    return $quiz;

}

/**

 * Delete all the attempts belonging to a quiz.

 *

 * @param stdClass $quiz The quiz object.

 */

function quiz_delete_all_attempts($quiz) {

    global $CFG, $DB;

    require_once($CFG->dirroot . '/mod/quiz/locallib.php');

    question_engine::delete_questions_usage_by_activities(new qubaids_for_quiz($quiz->id));

    $DB->delete_records('quiz_attempts', ['quiz' => $quiz->id]);

    $DB->delete_records('quiz_grades', ['quiz' => $quiz->id]);

}

/**

 * Delete all the attempts belonging to a user in a particular quiz.

 *

 * @param \mod_quiz\quiz_settings $quiz The quiz object.

 * @param stdClass $user The user object.

 */

function quiz_delete_user_attempts($quiz, $user) {

    global $CFG, $DB;

    require_once($CFG->dirroot . '/mod/quiz/locallib.php');

    question_engine::delete_questions_usage_by_activities(new qubaids_for_users_attempts(

            $quiz->get_quizid(), $user->id, 'all'));

    $params = [

        'quiz' => $quiz->get_quizid(),

        'userid' => $user->id,

    ];

    $DB->delete_records('quiz_attempts', $params);

    $DB->delete_records('quiz_grades', $params);

}

/**

 * Get the best current grade for a particular user in a quiz.

 *

 * @param stdClass $quiz the quiz settings.

 * @param int $userid the id of the user.

 * @return float the user's current grade for this quiz, or null if this user does

 * not have a grade on this quiz.

 */

function quiz_get_best_grade($quiz, $userid) {

    global $DB;

    $grade = $DB->get_field('quiz_grades', 'grade',

            ['quiz' => $quiz->id, 'userid' => $userid]);

    // Need to detect errors/no result, without catching 0 grades.

    if ($grade === false) {

        return null;

    }

    return $grade + 0; // Convert to number.

}

/**

 * Is this a graded quiz? If this method returns true, you can assume that

 * $quiz->grade and $quiz->sumgrades are non-zero (for example, if you want to

 * divide by them).

 *

 * @param stdClass $quiz a row from the quiz table.

 * @return bool whether this is a graded quiz.

 */

function quiz_has_grades($quiz) {

    return $quiz->grade >= grade_calculator::ALMOST_ZERO && $quiz->sumgrades >= grade_calculator::ALMOST_ZERO;

}

/**

 * Does this quiz allow multiple tries?

 *

 * @return bool

 */

function quiz_allows_multiple_tries($quiz) {

    $bt = question_engine::get_behaviour_type($quiz->preferredbehaviour);

    return $bt->allows_multiple_submitted_responses();

}

/**

 * Return a small object with summary information about what a

 * user has done with a given particular instance of this module

 * Used for user activity reports.

 * $return->time = the time they did it

 * $return->info = a short text description

 *

 * @param stdClass $course

 * @param stdClass $user

 * @param stdClass $mod

 * @param stdClass $quiz

 * @return stdClass|null

 */

function quiz_user_outline($course, $user, $mod, $quiz) {

    global $DB, $CFG;

    require_once($CFG->libdir . '/gradelib.php');

    $grades = grade_get_grades($course->id, 'mod', 'quiz', $quiz->id, $user->id);

    if (empty($grades->items[0]->grades)) {

        return null;

    } else {

        $grade = reset($grades->items[0]->grades);

    }

    $result = new stdClass();

    // If the user can't see hidden grades, don't return that information.

    $gitem = grade_item::fetch(['id' => $grades->items[0]->id]);

    if (!$gitem->hidden || has_capability('moodle/grade:viewhidden', context_course::instance($course->id))) {

        $result->info = get_string('gradenoun') . ': ' . $grade->str_long_grade;

    } else {

        $result->info = get_string('gradenoun') . ': ' . get_string('hidden', 'grades');

    }

    $result->time = grade_get_date_for_user_grade($grade, $user);

    return $result;

}

/**

 * Print a detailed representation of what a  user has done with

 * a given particular instance of this module, for user activity reports.

 *

 * @param stdClass $course

 * @param stdClass $user

 * @param stdClass $mod

 * @param stdClass $quiz

 * @return bool

 */

function quiz_user_complete($course, $user, $mod, $quiz) {

    global $DB, $CFG, $OUTPUT;

    require_once($CFG->libdir . '/gradelib.php');

    require_once($CFG->dirroot . '/mod/quiz/locallib.php');

    $grades = grade_get_grades($course->id, 'mod', 'quiz', $quiz->id, $user->id);

    if (!empty($grades->items[0]->grades)) {

        $grade = reset($grades->items[0]->grades);

        // If the user can't see hidden grades, don't return that information.

        $gitem = grade_item::fetch(['id' => $grades->items[0]->id]);

        if (!$gitem->hidden || has_capability('moodle/grade:viewhidden', context_course::instance($course->id))) {

            echo $OUTPUT->container(get_string('gradenoun').': '.$grade->str_long_grade);

            if ($grade->str_feedback) {

                echo $OUTPUT->container(get_string('feedback').': '.$grade->str_feedback);

            }

        } else {

            echo $OUTPUT->container(get_string('gradenoun') . ': ' . get_string('hidden', 'grades'));

            if ($grade->str_feedback) {

                echo $OUTPUT->container(get_string('feedback').': '.get_string('hidden', 'grades'));

            }

        }

    }

    if ($attempts = $DB->get_records('quiz_attempts',

            ['userid' => $user->id, 'quiz' => $quiz->id], 'attempt')) {

        foreach ($attempts as $attempt) {

            echo get_string('attempt', 'quiz', $attempt->attempt) . ': ';

            if ($attempt->state != quiz_attempt::FINISHED) {

                echo quiz_attempt_state_name($attempt->state);

            } else {

                if (!isset($gitem)) {

                    if (!empty($grades->items[0]->grades)) {

                        $gitem = grade_item::fetch(['id' => $grades->items[0]->id]);

                    } else {

                        $gitem = new stdClass();

                        $gitem->hidden = true;

                    }

                }

                if (!$gitem->hidden || has_capability('moodle/grade:viewhidden', context_course::instance($course->id))) {

                    echo quiz_format_grade($quiz, $attempt->sumgrades) . '/' . quiz_format_grade($quiz, $quiz->sumgrades);

                } else {

                    echo get_string('hidden', 'grades');

                }

                echo ' - '.userdate($attempt->timefinish).'<br />';

            }

        }

    } else {

        print_string('noattempts', 'quiz');

    }

    return true;

}

/**

 * @param int|array $quizids A quiz ID, or an array of quiz IDs.

 * @param int $userid the userid.

 * @param string $status 'all', 'finished' or 'unfinished' to control

 * @param bool $includepreviews

 * @return array of all the user's attempts at this quiz. Returns an empty

 *      array if there are none.

 */

function quiz_get_user_attempts($quizids, $userid, $status = 'finished', $includepreviews = false) {

    global $DB;

    $params = [];

    switch ($status) {

        case 'all':

            $statuscondition = '';

            break;

        case 'finished':

            $statuscondition = ' AND state IN (:state1, :state2)';

            $params['state1'] = quiz_attempt::FINISHED;

            $params['state2'] = quiz_attempt::ABANDONED;

            break;

        case 'unfinished':

            $statuscondition = ' AND state IN (:state1, :state2)';

            $params['state1'] = quiz_attempt::IN_PROGRESS;

            $params['state2'] = quiz_attempt::OVERDUE;

            break;

    }

    $quizids = (array) $quizids;

    list($insql, $inparams) = $DB->get_in_or_equal($quizids, SQL_PARAMS_NAMED);

    $params += $inparams;

    $params['userid'] = $userid;

    $previewclause = '';

    if (!$includepreviews) {

        $previewclause = ' AND preview = 0';

    }

    return $DB->get_records_select('quiz_attempts',

            "quiz $insql AND userid = :userid" . $previewclause . $statuscondition,

            $params, 'quiz, attempt ASC');

}

/**

 * Return grade for given user or all users.

 *

 * @param int $quizid id of quiz

 * @param int $userid optional user id, 0 means all users

 * @return array array of grades, false if none. These are raw grades. They should

 * be processed with quiz_format_grade for display.

 */

function quiz_get_user_grades($quiz, $userid = 0) {

    global $CFG, $DB;

    $params = [$quiz->id];

    $usertest = '';

    if ($userid) {

        $params[] = $userid;

        $usertest = 'AND u.id = ?';

    }

    return $DB->get_records_sql("

            SELECT

                u.id,

                u.id AS userid,

                qg.grade AS rawgrade,

                qg.timemodified AS dategraded,

                MAX(qa.timefinish) AS datesubmitted

            FROM {user} u

            JOIN {quiz_grades} qg ON u.id = qg.userid

            JOIN {quiz_attempts} qa ON qa.quiz = qg.quiz AND qa.userid = u.id

            WHERE qg.quiz = ?

            $usertest

            GROUP BY u.id, qg.grade, qg.timemodified", $params);

}

/**

 * Round a grade to the correct number of decimal places, and format it for display.

 *

 * @param stdClass $quiz The quiz table row, only $quiz->decimalpoints is used.

 * @param float|null $grade The grade to round and display (or null meaning no grade).

 * @return string

 */

function quiz_format_grade($quiz, $grade) {

    if (is_null($grade)) {

        return get_string('notyetgraded', 'quiz');

    }

    return format_float($grade, $quiz->decimalpoints);

}

/**

 * Determine the correct number of decimal places required to format a grade.

 *

 * @param stdClass $quiz The quiz table row, only $quiz->decimalpoints and

 *      ->questiondecimalpoints are used.

 * @return integer

 */

function quiz_get_grade_format($quiz) {

    if (empty($quiz->questiondecimalpoints)) {

        $quiz->questiondecimalpoints = -1;

    }

    if ($quiz->questiondecimalpoints == -1) {

        return $quiz->decimalpoints;

    }

    return $quiz->questiondecimalpoints;

}

/**

 * Round a grade to the correct number of decimal places, and format it for display.

 *

 * @param stdClass $quiz The quiz table row, only $quiz->decimalpoints is used.

 * @param float $grade The grade to round.

 * @return string

 */

function quiz_format_question_grade($quiz, $grade) {

    return format_float($grade, quiz_get_grade_format($quiz));

}

/**

 * Update grades in central gradebook

 *

 * @category grade

 * @param stdClass $quiz the quiz settings.

 * @param int $userid specific user only, 0 means all users.

 * @param bool $nullifnone If a single user is specified and $nullifnone is true a grade item with a null rawgrade will be inserted

 */

function quiz_update_grades($quiz, $userid = 0, $nullifnone = true) {

    global $CFG, $DB;

    require_once($CFG->libdir . '/gradelib.php');

    if ($quiz->grade == 0) {

        quiz_grade_item_update($quiz);

    } else if ($grades = quiz_get_user_grades($quiz, $userid)) {

        quiz_grade_item_update($quiz, $grades);

    } else if ($userid && $nullifnone) {

        $grade = new stdClass();

        $grade->userid = $userid;

        $grade->rawgrade = null;

        quiz_grade_item_update($quiz, $grade);

    } else {

        quiz_grade_item_update($quiz);

    }

}

/**

 * Create or update the grade item for given quiz

 *

 * @category grade

 * @param stdClass $quiz object with extra cmidnumber

 * @param mixed $grades optional array/object of grade(s); 'reset' means reset grades in gradebook

 * @return int 0 if ok, error code otherwise

 */

function quiz_grade_item_update($quiz, $grades = null) {

    global $CFG, $OUTPUT;

    require_once($CFG->dirroot . '/mod/quiz/locallib.php');

    require_once($CFG->libdir . '/gradelib.php');

    if (property_exists($quiz, 'cmidnumber')) { // May not be always present.

        $params = ['itemname' => $quiz->name, 'idnumber' => $quiz->cmidnumber];

    } else {

        $params = ['itemname' => $quiz->name];

    }

    if ($quiz->grade > 0) {

        $params['gradetype'] = GRADE_TYPE_VALUE;

        $params['grademax']  = $quiz->grade;

        $params['grademin']  = 0;

    } else {

        $params['gradetype'] = GRADE_TYPE_NONE;

    }

    // What this is trying to do:

    // 1. If the quiz is set to not show grades while the quiz is still open,

    //    and is set to show grades after the quiz is closed, then create the

    //    grade_item with a show-after date that is the quiz close date.

    // 2. If the quiz is set to not show grades at either of those times,

    //    create the grade_item as hidden.

    // 3. If the quiz is set to show grades, create the grade_item visible.

    $openreviewoptions = display_options::make_from_quiz($quiz,

            display_options::LATER_WHILE_OPEN);

    $closedreviewoptions = display_options::make_from_quiz($quiz,

            display_options::AFTER_CLOSE);

    if ($openreviewoptions->marks < question_display_options::MARK_AND_MAX &&

            $closedreviewoptions->marks < question_display_options::MARK_AND_MAX) {

        $params['hidden'] = 1;

    } else if ($openreviewoptions->marks < question_display_options::MARK_AND_MAX &&

            $closedreviewoptions->marks >= question_display_options::MARK_AND_MAX) {

        if ($quiz->timeclose) {

            $params['hidden'] = $quiz->timeclose;

        } else {

            $params['hidden'] = 1;

        }

    } else {

        // Either

        // a) both open and closed enabled

        // b) open enabled, closed disabled - we can not "hide after",

        //    grades are kept visible even after closing.

        $params['hidden'] = 0;

    }

    if (!$params['hidden']) {

        // If the grade item is not hidden by the quiz logic, then we need to

        // hide it if the quiz is hidden from students.

        if (property_exists($quiz, 'visible')) {

            // Saving the quiz form, and cm not yet updated in the database.

            $params['hidden'] = !$quiz->visible;

        } else {

            $cm = get_coursemodule_from_instance('quiz', $quiz->id);

            $params['hidden'] = !$cm->visible;

        }

    }

    if ($grades  === 'reset') {

        $params['reset'] = true;

        $grades = null;

    }

    $gradebook_grades = grade_get_grades($quiz->course, 'mod', 'quiz', $quiz->id);

    if (!empty($gradebook_grades->items)) {

        $grade_item = $gradebook_grades->items[0];

        if ($grade_item->locked) {

            // NOTE: this is an extremely nasty hack! It is not a bug if this confirmation fails badly. --skodak.

            $confirm_regrade = optional_param('confirm_regrade', 0, PARAM_INT);

            if (!$confirm_regrade) {

                if (!AJAX_SCRIPT) {

                    $message = get_string('gradeitemislocked', 'grades');

                    $back_link = $CFG->wwwroot . '/mod/quiz/report.php?q=' . $quiz->id .

                            '&mode=overview';

                    $regrade_link = qualified_me() . '&confirm_regrade=1';

                    echo $OUTPUT->box_start('generalbox', 'notice');

                    echo '<p>'. $message .'</p>';

                    echo $OUTPUT->container_start('buttons');

                    echo $OUTPUT->single_button($regrade_link, get_string('regradeanyway', 'grades'));

                    echo $OUTPUT->single_button($back_link,  get_string('cancel'));

                    echo $OUTPUT->container_end();

                    echo $OUTPUT->box_end();

                }

                return GRADE_UPDATE_ITEM_LOCKED;

            }

        }

    }

    return grade_update('mod/quiz', $quiz->course, 'mod', 'quiz', $quiz->id, 0, $grades, $params);

}

/**

 * Delete grade item for given quiz

 *

 * @category grade

 * @param stdClass $quiz object

 * @return int

 */

function quiz_grade_item_delete($quiz) {

    global $CFG;

    require_once($CFG->libdir . '/gradelib.php');

    return grade_update('mod/quiz', $quiz->course, 'mod', 'quiz', $quiz->id, 0,

            null, ['deleted' => 1]);

}

/**

 * This standard function will check all instances of this module

 * and make sure there are up-to-date events created for each of them.

 * If courseid = 0, then every quiz event in the site is checked, else

 * only quiz events belonging to the course specified are checked.

 * This function is used, in its new format, by restore_refresh_events()

 *

 * @param int $courseid

 * @param int|stdClass $instance Quiz module instance or ID.

 * @param int|stdClass $cm Course module object or ID (not used in this module).

 * @return bool

 */

function quiz_refresh_events($courseid = 0, $instance = null, $cm = null) {

    global $DB;

    // If we have instance information then we can just update the one event instead of updating all events.

    if (isset($instance)) {

        if (!is_object($instance)) {

            $instance = $DB->get_record('quiz', ['id' => $instance], '*', MUST_EXIST);

        }

        quiz_update_events($instance);

        return true;

    }

    if ($courseid == 0) {

        if (!$quizzes = $DB->get_records('quiz')) {

            return true;

        }

    } else {

        if (!$quizzes = $DB->get_records('quiz', ['course' => $courseid])) {

            return true;

        }

    }

    foreach ($quizzes as $quiz) {

        quiz_update_events($quiz);

    }

    return true;

}

/**

 * Returns all quiz graded users since a given time for specified quiz

 */

function quiz_get_recent_mod_activity(&$activities, &$index, $timestart,

        $courseid, $cmid, $userid = 0, $groupid = 0) {

    global $CFG, $USER, $DB;

    require_once($CFG->dirroot . '/mod/quiz/locallib.php');

    $course = get_course($courseid);

    $modinfo = get_fast_modinfo($course);

    $cm = $modinfo->cms[$cmid];

    $quiz = $DB->get_record('quiz', ['id' => $cm->instance]);

    if ($userid) {

        $userselect = "AND u.id = :userid";

        $params['userid'] = $userid;

    } else {

        $userselect = '';

    }

    if ($groupid) {

        $groupselect = 'AND gm.groupid = :groupid';

        $groupjoin   = 'JOIN {groups_members} gm ON  gm.userid=u.id';

        $params['groupid'] = $groupid;

    } else {

        $groupselect = '';

        $groupjoin   = '';

    }

    $params['timestart'] = $timestart;

    $params['quizid'] = $quiz->id;

    $userfieldsapi = \core_user\fields::for_userpic();

    $ufields = $userfieldsapi->get_sql('u', false, '', 'useridagain', false)->selects;

    if (!$attempts = $DB->get_records_sql("

              SELECT qa.*,

                     {$ufields}

                FROM {quiz_attempts} qa

                     JOIN {user} u ON u.id = qa.userid

                     $groupjoin

               WHERE qa.timefinish > :timestart

                 AND qa.quiz = :quizid

                 AND qa.preview = 0

                     $userselect

                     $groupselect

            ORDER BY qa.timefinish ASC", $params)) {

        return;

    }

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

    $accessallgroups = has_capability('moodle/site:accessallgroups', $context);

    $viewfullnames   = has_capability('moodle/site:viewfullnames', $context);

    $grader          = has_capability('mod/quiz:viewreports', $context);

    $groupmode       = groups_get_activity_groupmode($cm, $course);

    $usersgroups = null;

    $aname = format_string($cm->name, true);

    foreach ($attempts as $attempt) {

        if ($attempt->userid != $USER->id) {

            if (!$grader) {

                // Grade permission required.

                continue;

            }

            if ($groupmode == SEPARATEGROUPS and !$accessallgroups) {

                $usersgroups = groups_get_all_groups($course->id,

                        $attempt->userid, $cm->groupingid);

                $usersgroups = array_keys($usersgroups);

                if (!array_intersect($usersgroups, $modinfo->get_groups($cm->groupingid))) {

                    continue;

                }

            }

        }

        $options = quiz_get_review_options($quiz, $attempt, $context);

        $tmpactivity = new stdClass();

        $tmpactivity->type       = 'quiz';

        $tmpactivity->cmid       = $cm->id;

        $tmpactivity->name       = $aname;

        $tmpactivity->sectionnum = $cm->sectionnum;

        $tmpactivity->timestamp  = $attempt->timefinish;

        $tmpactivity->content = new stdClass();

        $tmpactivity->content->attemptid = $attempt->id;

        $tmpactivity->content->attempt   = $attempt->attempt;

        if (quiz_has_grades($quiz) && $options->marks >= question_display_options::MARK_AND_MAX) {

            $tmpactivity->content->sumgrades = quiz_format_grade($quiz, $attempt->sumgrades);

            $tmpactivity->content->maxgrade  = quiz_format_grade($quiz, $quiz->sumgrades);

        } else {

            $tmpactivity->content->sumgrades = null;

            $tmpactivity->content->maxgrade  = null;

        }

        $tmpactivity->user = user_picture::unalias($attempt, null, 'useridagain');

        $tmpactivity->user->fullname  = fullname($tmpactivity->user, $viewfullnames);

        $activities[$index++] = $tmpactivity;

    }

}

function quiz_print_recent_mod_activity($activity, $courseid, $detail, $modnames) {

    global $CFG, $OUTPUT;

    echo '<table border="0" cellpadding="3" cellspacing="0" class="forum-recent">';

    echo '<tr><td class="userpicture" valign="top">';

    echo $OUTPUT->user_picture($activity->user, ['courseid' => $courseid]);

    echo '</td><td>';

    if ($detail) {

        $modname = $modnames[$activity->type];

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

        echo $OUTPUT->image_icon('monologo', $modname, $activity->type);

        echo '<a href="' . $CFG->wwwroot . '/mod/quiz/view.php?id=' .

                $activity->cmid . '">' . $activity->name . '</a>';

        echo '</div>';

    }

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

    echo  get_string('attempt', 'quiz', $activity->content->attempt);

    if (isset($activity->content->maxgrade)) {

        $grades = $activity->content->sumgrades . ' / ' . $activity->content->maxgrade;

        echo ': (<a href="' . $CFG->wwwroot . '/mod/quiz/review.php?attempt=' .

                $activity->content->attemptid . '">' . $grades . '</a>)';

    }

    echo '</div>';

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

    echo '<a href="' . $CFG->wwwroot . '/user/view.php?id=' . $activity->user->id .

            '&course=' . $courseid . '">' . $activity->user->fullname .

            '</a> - ' . userdate($activity->timestamp);

    echo '</div>';

    echo '</td></tr></table>';

    return;

}

/**

 * Pre-process the quiz options form data, making any necessary adjustments.

 * Called by add/update instance in this file.

 *

 * @param stdClass $quiz The variables set on the form.

 */

function quiz_process_options($quiz) {

    global $CFG;

    require_once($CFG->dirroot . '/mod/quiz/locallib.php');

    require_once($CFG->libdir . '/questionlib.php');

    $quiz->timemodified = time();

    // Quiz name.

    if (!empty($quiz->name)) {

        $quiz->name = trim($quiz->name);

    }

    // Password field - different in form to stop browsers that remember passwords

    // getting confused.

    $quiz->password = $quiz->quizpassword;

    unset($quiz->quizpassword);

    // Quiz feedback.

    if (isset($quiz->feedbacktext)) {

        // Clean up the boundary text.

        for ($i = 0; $i < count($quiz->feedbacktext); $i += 1) {

            if (empty($quiz->feedbacktext[$i]['text'])) {

                $quiz->feedbacktext[$i]['text'] = '';

            } else {

                $quiz->feedbacktext[$i]['text'] = trim($quiz->feedbacktext[$i]['text']);

            }

        }

        // Check the boundary value is a number or a percentage, and in range.

        $i = 0;

        while (!empty($quiz->feedbackboundaries[$i])) {

            $boundary = trim($quiz->feedbackboundaries[$i]);

            if (!is_numeric($boundary)) {

                if (strlen($boundary) > 0 && $boundary[strlen($boundary) - 1] == '%') {

                    $boundary = trim(substr($boundary, 0, -1));

                    if (is_numeric($boundary)) {

                        $boundary = $boundary * $quiz->grade / 100.0;