C:/xampp/htdocs/moodle/question/engine/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/>.

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

require_once(dirname(__FILE__) . '/questionusage.php');
require_once(dirname(__FILE__) . '/questionattempt.php');
require_once(dirname(__FILE__) . '/questionattemptstep.php');
require_once(dirname(__FILE__) . '/states.php');
require_once(dirname(__FILE__) . '/datalib.php');
require_once(dirname(__FILE__) . '/renderer.php');
require_once(dirname(__FILE__) . '/bank.php');
require_once(dirname(__FILE__) . '/../type/questiontypebase.php');
require_once(dirname(__FILE__) . '/../type/questionbase.php');
require_once(dirname(__FILE__) . '/../type/rendererbase.php');
require_once(dirname(__FILE__) . '/../behaviour/behaviourbase.php');
require_once(dirname(__FILE__) . '/../behaviour/rendererbase.php');
require_once($CFG->libdir . '/questionlib.php');


abstract class question_engine {
    private static $loadedbehaviours = array();

    public static function make_questions_usage_by_activity($component, $context) {
        return new question_usage_by_activity($component, $context);
    }

    public static function load_questions_usage_by_activity($qubaid) {
        $dm = new question_engine_data_mapper();
        return $dm->load_questions_usage_by_activity($qubaid);
    }

    public static function save_questions_usage_by_activity(question_usage_by_activity $quba) {
        $dm = new question_engine_data_mapper();
        $observer = $quba->get_observer();
        if ($observer instanceof question_engine_unit_of_work) {
            $observer->save($dm);
        } else {
            $dm->insert_questions_usage_by_activity($quba);
        }
    }

    public static function delete_questions_usage_by_activity($qubaid) {
        self::delete_questions_usage_by_activities(new qubaid_list(array($qubaid)));
    }

    public static function delete_questions_usage_by_activities(qubaid_condition $qubaids) {
        $dm = new question_engine_data_mapper();
        $dm->delete_questions_usage_by_activities($qubaids);
    }

    public static function set_max_mark_in_attempts(qubaid_condition $qubaids,
            $slot, $newmaxmark) {
        $dm = new question_engine_data_mapper();
        $dm->set_max_mark_in_attempts($qubaids, $slot, $newmaxmark);
    }

    public static function questions_in_use(array $questionids, qubaid_condition $qubaids = null) {
        if (is_null($qubaids)) {
            return false;
        }
        $dm = new question_engine_data_mapper();
        return $dm->questions_in_use($questionids, $qubaids);
    }

    public static function make_archetypal_behaviour($preferredbehaviour, question_attempt $qa) {
        self::load_behaviour_class($preferredbehaviour);
        $class = 'qbehaviour_' . $preferredbehaviour;
        if (!constant($class . '::IS_ARCHETYPAL')) {
            throw new coding_exception('The requested behaviour is not actually ' .
                    'an archetypal one.');
        }
        return new $class($qa, $preferredbehaviour);
    }

    public static function get_behaviour_unused_display_options($behaviour) {
        self::load_behaviour_class($behaviour);
        $class = 'qbehaviour_' . $behaviour;
        if (!method_exists($class, 'get_unused_display_options')) {
            return question_behaviour::get_unused_display_options();
        }
        return call_user_func(array($class, 'get_unused_display_options'));
    }

    public static function make_behaviour($behaviour, question_attempt $qa, $preferredbehaviour) {
        try {
            self::load_behaviour_class($behaviour);
        } catch (Exception $e) {
            self::load_behaviour_class('missing');
            return new qbehaviour_missing($qa, $preferredbehaviour);
        }
        $class = 'qbehaviour_' . $behaviour;
        return new $class($qa, $preferredbehaviour);
    }

    public static function load_behaviour_class($behaviour) {
        global $CFG;
        if (isset(self::$loadedbehaviours[$behaviour])) {
            return;
        }
        $file = $CFG->dirroot . '/question/behaviour/' . $behaviour . '/behaviour.php';
        if (!is_readable($file)) {
            throw new coding_exception('Unknown question behaviour ' . $behaviour);
        }
        include_once($file);
        self::$loadedbehaviours[$behaviour] = 1;
    }

    public static function get_archetypal_behaviours() {
        $archetypes = array();
        $behaviours = get_plugin_list('qbehaviour');
        foreach ($behaviours as $behaviour => $notused) {
            if (self::is_behaviour_archetypal($behaviour)) {
                $archetypes[$behaviour] = self::get_behaviour_name($behaviour);
            }
        }
        asort($archetypes, SORT_LOCALE_STRING);
        return $archetypes;
    }

    public static function is_behaviour_archetypal($behaviour) {
        self::load_behaviour_class($behaviour);
        $plugin = 'qbehaviour_' . $behaviour;
        return constant($plugin . '::IS_ARCHETYPAL');
    }

    public static function sort_behaviours($archetypes, $orderlist, $disabledlist, $current=null) {

        // Get disabled behaviours
        if ($disabledlist) {
            $disabled = explode(',', $disabledlist);
        } else {
            $disabled = array();
        }

        if ($orderlist) {
            $order = explode(',', $orderlist);
        } else {
            $order = array();
        }

        foreach ($disabled as $behaviour) {
            if (array_key_exists($behaviour, $archetypes) && $behaviour != $current) {
                unset($archetypes[$behaviour]);
            }
        }

        // Get behaviours in preferred order
        $behaviourorder = array();
        foreach ($order as $behaviour) {
            if (array_key_exists($behaviour, $archetypes)) {
                $behaviourorder[$behaviour] = $archetypes[$behaviour];
            }
        }
        // Get the rest of behaviours and sort them alphabetically
        $leftover = array_diff_key($archetypes, $behaviourorder);
        asort($leftover, SORT_LOCALE_STRING);

        // Set up the final order to be displayed
        return $behaviourorder + $leftover;
    }

    public static function get_behaviour_options($currentbehaviour) {
        $config = question_bank::get_config();
        $archetypes = self::get_archetypal_behaviours();

        // If no admin setting return all behavious
        if (empty($config->disabledbehaviours) && empty($config->behavioursortorder)) {
            return $archetypes;
        }

        if (empty($config->behavioursortorder)) {
            $order = '';
        } else {
            $order = $config->behavioursortorder;
        }
        if (empty($config->disabledbehaviours)) {
            $disabled = '';
        } else {
            $disabled = $config->disabledbehaviours;
        }

        return self::sort_behaviours($archetypes, $order, $disabled, $currentbehaviour);
    }

    public static function get_behaviour_name($behaviour) {
        return get_string('pluginname', 'qbehaviour_' . $behaviour);
    }

    public static function get_all_response_file_areas() {
        $variables = array();
        foreach (question_bank::get_all_qtypes() as $qtype) {
            $variables += $qtype->response_file_areas();
        }

        $areas = array();
        foreach (array_unique($variables) as $variable) {
            $areas[] = 'response_' . $variable;
        }
        return $areas;
    }

    public static function get_dp_options() {
        return question_display_options::get_dp_options();
    }

    public static function initialise_js() {
        return question_flags::initialise_js();
    }
}


class question_display_options {
    const HIDDEN = 0;
    const VISIBLE = 1;
    const EDITABLE = 2;
    const MAX_ONLY = 1;
    const MARK_AND_MAX = 2;
    const MAX_DP = 7;

    public $readonly = false;

    public $clearwrong = false;

    public $correctness = self::VISIBLE;

    public $marks = self::MARK_AND_MAX;

    public $markdp = 2;

    public $flags = self::VISIBLE;

    public $feedback = self::VISIBLE;

    public $numpartscorrect = self::VISIBLE;

    public $generalfeedback = self::VISIBLE;

    public $rightanswer = self::VISIBLE;

    public $manualcomment = self::VISIBLE;

    public $manualcommentlink = null;

    public $questionreviewlink = null;

    public $history = self::HIDDEN;

    public $editquestionparams = array();

    public $context;

    public function hide_all_feedback() {
        $this->feedback = self::HIDDEN;
        $this->numpartscorrect = self::HIDDEN;
        $this->generalfeedback = self::HIDDEN;
        $this->rightanswer = self::HIDDEN;
        $this->manualcomment = self::HIDDEN;
        $this->correctness = self::HIDDEN;
    }

    public static function get_dp_options() {
        $options = array();
        for ($i = 0; $i <= self::MAX_DP; $i += 1) {
            $options[$i] = $i;
        }
        return $options;
    }
}


abstract class question_flags {
    protected static function get_toggle_checksum($qubaid, $questionid,
            $qaid, $slot, $user = null) {
        if (is_null($user)) {
            global $USER;
            $user = $USER;
        }
        return md5($qubaid . "_" . $user->secret . "_" . $questionid . "_" . $qaid . "_" . $slot);
    }

    public static function get_postdata(question_attempt $qa) {
        $qaid = $qa->get_database_id();
        $qubaid = $qa->get_usage_id();
        $qid = $qa->get_question()->id;
        $slot = $qa->get_slot();
        $checksum = self::get_toggle_checksum($qubaid, $qid, $qaid, $slot);
        return "qaid=$qaid&qubaid=$qubaid&qid=$qid&slot=$slot&checksum=$checksum&sesskey=" .
                sesskey() . '&newstate=';
    }

    public static function update_flag($qubaid, $questionid, $qaid, $slot, $checksum, $newstate) {
        // Check the checksum - it is very hard to know who a question session belongs
        // to, so we require that checksum parameter is matches an md5 hash of the
        // three ids and the users username. Since we are only updating a flag, that
        // probably makes it sufficiently difficult for malicious users to toggle
        // other users flags.
        if ($checksum != self::get_toggle_checksum($qubaid, $questionid, $qaid, $slot)) {
            throw new moodle_exception('errorsavingflags', 'question');
        }

        $dm = new question_engine_data_mapper();
        $dm->update_question_attempt_flag($qubaid, $questionid, $qaid, $slot, $newstate);
    }

    public static function initialise_js() {
        global $CFG, $PAGE, $OUTPUT;
        static $done = false;
        if ($done) {
            return;
        }
        $module = array(
            'name' => 'core_question_flags',
            'fullpath' => '/question/flags.js',
            'requires' => array('base', 'dom', 'event-delegate', 'io-base'),
        );
        $actionurl = $CFG->wwwroot . '/question/toggleflag.php';
        $flagtext = array(
            0 => get_string('clickflag', 'question'),
            1 => get_string('clickunflag', 'question')
        );
        $flagattributes = array(
            0 => array(
                'src' => $OUTPUT->pix_url('i/unflagged') . '',
                'title' => get_string('clicktoflag', 'question'),
                'alt' => get_string('notflagged', 'question'),
              //  'text' => get_string('clickflag', 'question'),
            ),
            1 => array(
                'src' => $OUTPUT->pix_url('i/flagged') . '',
                'title' => get_string('clicktounflag', 'question'),
                'alt' => get_string('flagged', 'question'),
               // 'text' => get_string('clickunflag', 'question'),
            ),
        );
        $PAGE->requires->js_init_call('M.core_question_flags.init',
                array($actionurl, $flagattributes, $flagtext), false, $module);
        $done = true;
    }
}


class question_out_of_sequence_exception extends moodle_exception {
    public function __construct($qubaid, $slot, $postdata) {
        if ($postdata == null) {
            $postdata = data_submitted();
        }
        parent::__construct('submissionoutofsequence', 'question', '', null,
                "QUBAid: $qubaid, slot: $slot, post data: " . print_r($postdata, true));
    }
}


abstract class question_utils {
    public static function arrays_have_same_keys_and_values(array $array1, array $array2) {
        if (count($array1) != count($array2)) {
            return false;
        }
        foreach ($array1 as $key => $value1) {
            if (!array_key_exists($key, $array2)) {
                return false;
            }
            if (((string) $value1) !== ((string) $array2[$key])) {
                return false;
            }
        }
        return true;
    }

    public static function arrays_same_at_key(array $array1, array $array2, $key) {
        if (array_key_exists($key, $array1) && array_key_exists($key, $array2)) {
            return ((string) $array1[$key]) === ((string) $array2[$key]);
        }
        if (!array_key_exists($key, $array1) && !array_key_exists($key, $array2)) {
            return true;
        }
        return false;
    }

    public static function arrays_same_at_key_missing_is_blank(
            array $array1, array $array2, $key) {
        if (array_key_exists($key, $array1)) {
            $value1 = $array1[$key];
        } else {
            $value1 = '';
        }
        if (array_key_exists($key, $array2)) {
            $value2 = $array2[$key];
        } else {
            $value2 = '';
        }
        return ((string) $value1) === ((string) $value2);
    }

    public static function arrays_same_at_key_integer(
            array $array1, array $array2, $key) {
        if (array_key_exists($key, $array1)) {
            $value1 = $array1[$key];
        } else {
            $value1 = 0;
        }
        if (array_key_exists($key, $array2)) {
            $value2 = $array2[$key];
        } else {
            $value2 = 0;
        }
        return ((integer) $value1) === ((integer) $value2);
    }

    private static $units     = array('', 'i', 'ii', 'iii', 'iv', 'v', 'vi', 'vii', 'viii', 'ix');
    private static $tens      = array('', 'x', 'xx', 'xxx', 'xl', 'l', 'lx', 'lxx', 'lxxx', 'xc');
    private static $hundreds  = array('', 'c', 'cc', 'ccc', 'cd', 'd', 'dc', 'dcc', 'dccc', 'cm');
    private static $thousands = array('', 'm', 'mm', 'mmm');

    public static function int_to_roman($number) {
        if (!is_integer($number) || $number < 1 || $number > 3999) {
            throw new coding_exception('Only integers between 0 and 3999 can be ' .
                    'converted to roman numerals.', $number);
        }

        return self::$thousands[$number / 1000 % 10] . self::$hundreds[$number / 100 % 10] .
                self::$tens[$number / 10 % 10] . self::$units[$number % 10];
    }
}


interface question_variant_selection_strategy {
    public function choose_variant($maxvariants, $seed);
}


class question_variant_random_strategy implements question_variant_selection_strategy {
    public function choose_variant($maxvariants, $seed) {
        return rand(1, $maxvariants);
    }
}


class question_variant_pseudorandom_no_repeats_strategy
        implements question_variant_selection_strategy {

    protected $attemptno;

    protected $userid;

    public function __construct($attemptno, $userid = null) {
        $this->attemptno = $attemptno;
        if (is_null($userid)) {
            global $USER;
            $this->userid = $USER->id;
        } else {
            $this->userid = $userid;
        }
    }

    public function choose_variant($maxvariants, $seed) {
        if ($maxvariants == 1) {
            return 1;
        }

        $hash = sha1($seed . '|user' . $this->userid);
        $randint = hexdec(substr($hash, 17, 7));

        return ($randint + $this->attemptno) % $maxvariants + 1;
    }
}