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/>.

/**

 * Class to print a view of the question bank.

 *

 * @package   core_question

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

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

 */

namespace core_question\local\bank;

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

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

use coding_exception;

use core\plugininfo\qbank;

use core\output\datafilter;

use core_plugin_manager;

use core_question\local\bank\condition;

use core_question\local\statistics\statistics_bulk_loader;

use core_question\output\question_bank_filter_ui;

use core_question\local\bank\column_manager_base;

use qbank_deletequestion\hidden_condition;

use qbank_editquestion\editquestion_helper;

use qbank_managecategories\category_condition;

/**

 * This class prints a view of the question bank.

 *

 * including

 *  + Some controls to allow users to to select what is displayed.

 *  + A list of questions as a table.

 *  + Further controls to do things with the questions.

 *

 * This class gives a basic view, and provides plenty of hooks where subclasses

 * can override parts of the display.

 *

 * The list of questions presented as a table is generated by creating a list of

 * core_question\bank\column objects, one for each 'column' to be displayed. These

 * manage

 *  + outputting the contents of that column, given a $question object, but also

 *  + generating the right fragments of SQL to ensure the necessary data is present,

 *    and sorted in the right order.

 *  + outputting table headers.

 *

 * @copyright 2009 Tim Hunt

 * @author    2021 Safat Shahin <safatshahin@catalyst-au.net>

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

 */

class view {

    /**

     * Maximum number of sorts allowed.

     */

    const MAX_SORTS = 3;

    /**

     * @var \moodle_url base URL for the current page. Used as the

     * basis for making URLs for actions that reload the page.

     */

    protected $baseurl;

    /**

     * @var \moodle_url used as a basis for URLs that edit a question.

     */

    protected $editquestionurl;

    /**

     * @var \core_question\local\bank\question_edit_contexts

     */

    public $contexts;

    /**

     * @var object|\cm_info|null if we are in a module context, the cm.

     */

    public $cm;

    /**

     * @var object the course we are within.

     */

    public $course;

    /**

     * @var column_base[] these are all the 'columns' that are

     * part of the display. Array keys are the class name.

     */

    protected $requiredcolumns;

    /**

     * @var question_action_base[] these are all the actions that can be displayed in a question's action menu.

     *

     * Array keys are the class name.

     */

    protected $questionactions;

    /**

     * @var column_base[] these are the 'columns' that are

     * actually displayed as a column, in order. Array keys are the class name.

     */

    protected $visiblecolumns;

    /**

     * @var column_base[] these are the 'columns' that are

     * common to the question bank.

     */

    protected $corequestionbankcolumns;

    /**

     * @var column_base[] these are the 'columns' that are

     * actually displayed as an additional row (e.g. question text), in order.

     * Array keys are the class name.

     */

    protected $extrarows;

    /**

     * @var array list of column class names for which columns to sort on.

     */

    protected $sort;

    /**

     * @var int page size to use (when we are not showing all questions).

     */

    protected $pagesize = DEFAULT_QUESTIONS_PER_PAGE;

    /**

     * @var int|null id of the a question to highlight in the list (if present).

     */

    protected $lastchangedid;

    /**

     * @var string SQL to count the number of questions matching the current

     * search conditions.

     */

    protected $countsql;

    /**

     * @var string SQL to actually load the question data to display.

     */

    protected $loadsql;

    /**

     * @var array params used by $countsql and $loadsql (which currently must be the same).

     */

    protected $sqlparams;

    /**

     * @var ?array Stores all the average statistics that this question bank view needs.

     *

     * This field gets initialised in {@see display_question_list()}. It is a two dimensional

     * $this->loadedstatistics[$questionid][$fieldname] = $average value of that statistics for that question.

     * Column classes in qbank plugins can access these values using {@see get_aggregate_statistic()}.

     */

    protected $loadedstatistics = null;

    /**

     * @var condition[] search conditions.

     */

    protected $searchconditions = [];

    /**

     * @var string url of the new question page.

     */

    public $returnurl;

    /**

     * @var array $bulkactions to identify the bulk actions for the api.

     */

    public $bulkactions = [];

    /**

     * @var int|null Number of questions.

     */

    protected $totalcount = null;

    /**

     * @var array Parameters for the page URL.

     */

    protected $pagevars = [];

    /**

     * @var plugin_features_base[] $plugins Plugin feature objects for all enabled qbank plugins.

     */

    protected $plugins = [];

    /**

     * @var string $component the component the api is used from.

     */

    public $component = 'core_question';

    /**

     * @var string $callback name of the callback for the api call via filter js.

     */

    public $callback = 'question_data';

    /**

     * @var array $extraparams extra parameters for the extended apis.

     */

    public $extraparams = [];

    /**

     * @var column_manager_base $columnmanager The column manager, can be overridden by plugins.

     */

    protected $columnmanager;

    /**

     * Constructor for view.

     *

     * @param \core_question\local\bank\question_edit_contexts $contexts

     * @param \moodle_url $pageurl

     * @param object $course course settings

     * @param null $cm (optional) activity settings.

     * @param array $params the parameters required to initialize the api.

     * @param array $extraparams any extra parameters required by a particular view class.

     */

    public function __construct($contexts, $pageurl, $course, $cm = null, $params = [], $extraparams = []) {

        $this->contexts = $contexts;

        $this->baseurl = $pageurl;

        $this->course = $course;

        $this->cm = $cm;

        $this->extraparams = $extraparams;

        // Default filter condition.

        if (!isset($params['filter']) && isset($params['cat'])) {

            $params['filter']  = [];

            [$categoryid, $contextid] = category_condition::validate_category_param($params['cat']);

            if (!is_null($categoryid)) {

                $category = category_condition::get_category_record($categoryid, $contextid);

                $params['filter']['category'] = [

                    'jointype' => category_condition::JOINTYPE_DEFAULT,

                    'values' => [$category->id],

                    'filteroptions' => ['includesubcategories' => false],

                ];

            }

            $params['filter']['hidden'] = [

                'jointype' => hidden_condition::JOINTYPE_DEFAULT,

                'values' => [0],

            ];

            $params['jointype'] = datafilter::JOINTYPE_ALL;

        }

        if (!empty($params['filter'])) {

            $params['filter'] = filter_condition_manager::unpack_filteroptions_param($params['filter']);

        }

        if (isset($params['filter']['jointype'])) {

            $params['jointype'] = $params['filter']['jointype'];

            unset($params['filter']['jointype']);

        }

        // Create the url of the new question page to forward to.

        $this->returnurl = $pageurl->out_as_local_url(false);

        $this->editquestionurl = new \moodle_url('/question/bank/editquestion/question.php', ['returnurl' => $this->returnurl]);

        if ($this->cm !== null) {

            $this->editquestionurl->param('cmid', $this->cm->id);

        } else {

            $this->editquestionurl->param('courseid', $this->course->id);

        }

        $this->lastchangedid = clean_param($pageurl->param('lastchanged'), PARAM_INT);

        $this->init_plugins();

        $this->init_column_manager();

        // Possibly the heading part can be removed.

        $this->set_pagevars($params);

        $this->init_columns($this->wanted_columns(), $this->heading_column());

        $this->init_question_actions();

        $this->init_sort();

        $this->init_bulk_actions();

    }

    /**

     * Get an array of plugin features objects for all enabled qbank plugins.

     *

     * @return void

     */

    protected function init_plugins(): void {

        $plugins = \core_component::get_plugin_list_with_class('qbank', 'plugin_feature', 'plugin_feature.php');

        foreach ($plugins as $componentname => $pluginclass) {

            if (!\core\plugininfo\qbank::is_plugin_enabled($componentname)) {

                continue;

            }

            $this->plugins[$componentname] = new $pluginclass();

        }

        // Sort plugin list by component name.

        ksort($this->plugins);

    }

    /**

     * Allow qbank plugins to override the column manager.

     *

     * If multiple qbank plugins define a column manager, this will pick the first one sorted alphabetically.

     *

     * @return void

     */

    protected function init_column_manager(): void {

        $this->columnmanager = new column_manager_base();

        foreach ($this->plugins as $plugin) {

            if ($columnmanager = $plugin->get_column_manager()) {

                $this->columnmanager = $columnmanager;

                break;

            }

        }

    }

    /**

     * Initialize bulk actions.

     */

    protected function init_bulk_actions(): void {

        foreach ($this->plugins as $componentname => $plugin) {

            $bulkactions = $plugin->get_bulk_actions();

            if (!is_array($bulkactions)) {

                debugging("The method {$componentname}::get_bulk_actions() must return an " .

                    "array of bulk actions instead of a single bulk action. " .

                    "Please update your implementation of get_bulk_actions() to return an array. " .

                    "Check out the qbank_bulkmove plugin for a working example.", DEBUG_DEVELOPER);

                $bulkactions = [$bulkactions];

            }

            foreach ($bulkactions as $bulkactionobject) {

                $this->bulkactions[$bulkactionobject->get_key()] = [

                    'title' => $bulkactionobject->get_bulk_action_title(),

                    'url' => $bulkactionobject->get_bulk_action_url(),

                    'capabilities' => $bulkactionobject->get_bulk_action_capabilities()

                ];

            }

        }

    }

    /**

     * Initialize search conditions from plugins

     * local_*_get_question_bank_search_conditions() must return an array of

     * \core_question\bank\search\condition objects.

     *

     * @deprecated Since Moodle 4.3

     * @todo Final deprecation on Moodle 4.7 MDL-78090

     */

    protected function init_search_conditions(): void {

        debugging(

            'Function init_search_conditions() has been deprecated, please create a qbank plugin' .

                'and implement a filter object instead.',

            DEBUG_DEVELOPER

        );

        $searchplugins = get_plugin_list_with_function('local', 'get_question_bank_search_conditions');

        foreach ($searchplugins as $component => $function) {

            foreach ($function($this) as $searchobject) {

                $this->add_searchcondition($searchobject);

            }

        }

    }

    /**

     * Initialise list of menu actions for enabled question bank plugins.

     *

     * Menu action objects are stored in $this->menuactions, keyed by class name.

     *

     * @return void

     */

    protected function init_question_actions(): void {

        $this->questionactions = [];

        foreach ($this->plugins as $plugin) {

            $menuactions = $plugin->get_question_actions($this);

            foreach ($menuactions as $menuaction) {

                $this->questionactions[$menuaction::class] = $menuaction;

                if ($menuaction->get_menu_position() === question_action_base::MENU_POSITION_NOT_SET) {

                    debugging('Question bank actions must define the get_menu_position method. ' .

                        $menuaction::class . ' does not.', DEBUG_DEVELOPER);

                }

            }

        }

        // Sort according to each action's desired position.

        // Note, we are relying on the sort to be stable for

        // equal values of get_menu_position.

        uasort(

            $this->questionactions,

            function (question_action_base $a, question_action_base $b) {

                return $a->get_menu_position() <=> $b->get_menu_position();

            },

        );

    }

    /**

     * Get class for each question bank columns.

     *

     * @return array

     */

    protected function get_question_bank_plugins(): array {

        $questionbankclasscolumns = [];

        $newpluginclasscolumns = [];

        $corequestionbankcolumns = [

            'core_question\local\bank\checkbox_column' . column_base::ID_SEPARATOR . 'checkbox_column',

            'core_question\local\bank\edit_menu_column' . column_base::ID_SEPARATOR . 'edit_menu_column',

        ];

        foreach ($corequestionbankcolumns as $columnid) {

            [$columnclass, $columnname] = explode(column_base::ID_SEPARATOR, $columnid, 2);

            if (class_exists($columnclass)) {

                $questionbankclasscolumns[$columnid] = $columnclass::from_column_name($this, $columnname);

            }

        }

        foreach ($this->plugins as $plugin) {

            $plugincolumnobjects = $plugin->get_question_columns($this);

            foreach ($plugincolumnobjects as $columnobject) {

                $columnid = $columnobject->get_column_id();

                foreach ($corequestionbankcolumns as $corequestionbankcolumn) {

                    // Check if it has custom preference selector to view/hide.

                    if ($columnobject->has_preference()) {

                        if (!$columnobject->get_preference()) {

                            continue;

                        }

                    }

                    if ($corequestionbankcolumn === $columnid) {

                        $questionbankclasscolumns[$columnid] = $columnobject;

                    } else {

                        // Any community plugin for column/action.

                        $newpluginclasscolumns[$columnid] = $columnobject;

                    }

                }

            }

        }

        // New plugins added at the end of the array, will change in sorting feature.

        foreach ($newpluginclasscolumns as $key => $newpluginclasscolumn) {

            $questionbankclasscolumns[$key] = $newpluginclasscolumn;

        }

        $questionbankclasscolumns = $this->columnmanager->get_sorted_columns($questionbankclasscolumns);

        $questionbankclasscolumns = $this->columnmanager->set_columns_visibility($questionbankclasscolumns);

        // Mitigate the error in case of any regression.

        foreach ($questionbankclasscolumns as $shortname => $questionbankclasscolumn) {

            if (!is_object($questionbankclasscolumn) || !$questionbankclasscolumn->isvisible) {

                unset($questionbankclasscolumns[$shortname]);

            }

        }

        return $questionbankclasscolumns;

    }

    /**

     * Loads all the available columns.

     *

     * @return array

     */

    protected function wanted_columns(): array {

        $this->requiredcolumns = [];

        $questionbankcolumns = $this->get_question_bank_plugins();

        foreach ($questionbankcolumns as $classobject) {

            if (empty($classobject) || !($classobject instanceof \core_question\local\bank\column_base)) {

                continue;

            }

            $this->requiredcolumns[$classobject->get_column_name()] = $classobject;

        }

        return $this->requiredcolumns;

    }

    /**

     * Check a column object from its name and get the object for sort.

     *

     * @param string $columnname

     */

    protected function get_column_type($columnname) {

        if (empty($this->requiredcolumns[$columnname])) {

            $this->requiredcolumns[$columnname] = new $columnname($this);

        }

    }

    /**

     * Specify the column heading

     *

     * @return string Column name for the heading

     */

    protected function heading_column(): string {

        return 'qbank_viewquestionname\viewquestionname_column_helper';

    }

    /**

     * Initializing table columns

     *

     * @param array $wanted Collection of column names

     * @param string $heading The name of column that is set as heading

     */

    protected function init_columns($wanted, $heading = ''): void {

        // Now split columns into real columns and rows.

        $this->visiblecolumns = [];

        $this->extrarows = [];

        foreach ($wanted as $column) {

            if ($column->is_extra_row()) {

                $this->extrarows[$column->get_column_name()] = $column;

            } else {

                // Only add columns which are visible.

                if ($column->isvisible) {

                    $this->visiblecolumns[$column->get_column_name()] = $column;

                }

            }

        }

        if (array_key_exists($heading, $this->requiredcolumns)) {

            $this->requiredcolumns[$heading]->set_as_heading();

        }

    }

    /**

     * Checks if the column included in the output.

     *

     * @param string $colname a column internal name.

     * @return bool is this column included in the output?

     */

    public function has_column($colname): bool {

        return isset($this->visiblecolumns[$colname]);

    }

    /**

     * Get the count of the columns.

     *

     * @return int The number of columns in the table.

     */

    public function get_column_count(): int {

        return count($this->visiblecolumns);

    }

    /**

     * Get course id.

     * @return mixed

     */

    public function get_courseid() {

        return $this->course->id;

    }

    /**

     * Initialise sorting.

     */

    protected function init_sort(): void {

        $this->sort = [];

        $sorts = optional_param_array('sortdata', [], PARAM_INT);

        if (empty($sorts)) {

            $sorts = $this->get_pagevars('sortdata');

        }

        if (empty($sorts)) {

            $sorts = $this->default_sort();

        }

        $sorts = array_slice($sorts, 0, self::MAX_SORTS);

        foreach ($sorts as $sortname => $sortorder) {

            // Deal with subsorts.

            [$colname] = $this->parse_subsort($sortname);

            $this->get_column_type($colname);

        }

        $this->sort = $sorts;

    }

    /**

     * Deal with a sort name of the form columnname, or colname_subsort by

     * breaking it up, validating the bits that are present, and returning them.

     * If there is no subsort, then $subsort is returned as ''.

     *

     * @param string $sort the sort parameter to process.

     * @return array [$colname, $subsort].

     */

    protected function parse_subsort($sort): array {

        // Do the parsing.

        if (strpos($sort, '-') !== false) {

            list($colname, $subsort) = explode('-', $sort, 2);

        } else {

            $colname = $sort;

            $subsort = '';

        }

        $colname = str_replace('__', '\\', $colname);

        // Validate the column name.

        $this->get_column_type($colname);

        $column = $this->requiredcolumns[$colname];

        if (!isset($column) || !$column->is_sortable()) {

            $this->baseurl->remove_params('sortdata');

            throw new \moodle_exception('unknownsortcolumn', '', $this->baseurl->out(), $colname);

        }

        // Validate the subsort, if present.

        if ($subsort) {

            $subsorts = $column->is_sortable();

            if (!is_array($subsorts) || !isset($subsorts[$subsort])) {

                throw new \moodle_exception('unknownsortcolumn', '', $this->baseurl->out(), $sort);

            }

        }

        return [$colname, $subsort];

    }

    /**

     * Sort to parameters.

     *

     * @param array $sorts

     * @return array

     */

    protected function sort_to_params($sorts): array {

        $params = [];

        foreach ($sorts as $sortname => $sortorder) {

            $params['sortdata[' . $sortname . ']'] = $sortorder;

        }

        return $params;

    }

    /**

     * Default sort for question data.

     * @return int[]

     */

    protected function default_sort(): array {

        $defaultsort = [];

        if (class_exists('\\qbank_viewquestiontype\\question_type_column')) {

            $defaultsort['qbank_viewquestiontype__question_type_column'] = SORT_ASC;

        }

        if (class_exists('\\qbank_viewquestionname\\question_name_idnumber_tags_column')) {

            $defaultsort['qbank_viewquestionname__question_name_idnumber_tags_column-name'] = SORT_ASC;

        }

        return $defaultsort;

    }

    /**

     * Gets the primary sort order according to the default sort.

     *

     * @param string $sortname a column or column_subsort name.

     * @return int the current sort order for this column -1, 0, 1

     */

    public function get_primary_sort_order($sortname): int {

        $order = reset($this->sort);

        $primarysort = key($this->sort);

        if ($sortname == $primarysort) {

            return $order;

        }

        return 0;

    }

    /**

     * Get a URL to redisplay the page with a new sort for the question bank.

     *

     * @param string $sortname the column, or column_subsort to sort on.

     * @param bool $newsortreverse whether to sort in reverse order.

     * @return string The new URL.

     */

    public function new_sort_url($sortname, $newsortreverse): string {

        // Tricky code to add the new sort at the start, removing it from where it was before, if it was present.

        $newsort = array_reverse($this->sort);

        if (isset($newsort[$sortname])) {

            unset($newsort[$sortname]);

        }

        $newsort[$sortname] = $newsortreverse ? SORT_DESC : SORT_ASC;

        $newsort = array_reverse($newsort);

        if (count($newsort) > self::MAX_SORTS) {

            $newsort = array_slice($newsort, 0, self::MAX_SORTS, true);

        }

        return $this->baseurl->out(true, $this->sort_to_params($newsort));

    }

    /**

     * Return an array 'table_alias' => 'JOIN clause' to bring in any data that

     * the core view requires.

     *

     * @return string[] 'table_alias' => 'JOIN clause'

     */

    protected function get_required_joins(): array {

        return [

            'qv' => 'JOIN {question_versions} qv ON qv.questionid = q.id',

            'qbe' => 'JOIN {question_bank_entries} qbe on qbe.id = qv.questionbankentryid',

            'qc' => 'JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid',

        ];

    }

    /**

     * Return an array of fields for any data that the core view requires.

     *

     * Use table alias 'q' for the question table, or one of the ones from get_required_joins.

     * Every field requested must specify a table prefix.

     *

     * @return string[] fields required.

     */

    protected function get_required_fields(): array {

        return [

            'q.id',

            'q.qtype',

            'q.createdby',

            'qc.id as categoryid',

            'qc.contextid',

            'qv.status',

            'qv.version',

            'qv.id as versionid',

            'qbe.id as questionbankentryid',

        ];

    }

    /**

     * Gather query requirements from view component objects.

     *

     * This will take the required fields and joins for this view, and combine them with those for all active view components.

     * Fields will be de-duplicated in multiple components require the same field.

     * Joins will be de-duplicated if the alias and join clause match exactly.

     *

     * @throws \coding_exception If two components attempt to use the same alias for different joins.

     * @param view_component[] $viewcomponents List of component objects included in the current view

     * @return array [$fields, $joins] SQL fields and joins to add to the query.

     */

    protected function get_component_requirements(array $viewcomponents): array {

        $fields = $this->get_required_fields();

        $joins = $this->get_required_joins();

        if (!empty($viewcomponents)) {

            foreach ($viewcomponents as $viewcomponent) {

                $extrajoins = $viewcomponent->get_extra_joins();

                foreach ($extrajoins as $prefix => $join) {

                    if (isset($joins[$prefix]) && $joins[$prefix] != $join) {

                        throw new \coding_exception('Join ' . $join . ' conflicts with previous join ' . $joins[$prefix]);

                    }

                    $joins[$prefix] = $join;

                }

                $fields = array_merge($fields, $viewcomponent->get_required_fields());

            }

        }

        return [array_unique($fields), $joins];

    }

    /**

     * Create the SQL query to retrieve the indicated questions, based on

     * \core_question\bank\search\condition filters.

     */

    protected function build_query(): void {

        // Get the required tables and fields.

        [$fields, $joins] = $this->get_component_requirements(array_merge($this->requiredcolumns, $this->questionactions));

        // Build the order by clause.

        $sorts = [];

        foreach ($this->sort as $sortname => $sortorder) {

            [$colname, $subsort] = $this->parse_subsort($sortname);

            $sorts[] = $this->requiredcolumns[$colname]->sort_expression($sortorder == SORT_DESC, $subsort);

        }

        // Build the where clause.

        $latestversion = 'qv.version = (SELECT MAX(v.version)

                                          FROM {question_versions} v

                                          JOIN {question_bank_entries} be

                                            ON be.id = v.questionbankentryid

                                         WHERE be.id = qbe.id)';

        $this->sqlparams = [];

        $conditions = [];

        foreach ($this->searchconditions as $searchcondition) {

            if ($searchcondition->where()) {

                $conditions[] = '((' . $searchcondition->where() .'))';

            }

            if ($searchcondition->params()) {

                $this->sqlparams = array_merge($this->sqlparams, $searchcondition->params());

            }

        }

        // Get higher level filter condition.

        $jointype = isset($this->pagevars['jointype']) ? (int)$this->pagevars['jointype'] : condition::JOINTYPE_DEFAULT;

        $nonecondition = ($jointype === datafilter::JOINTYPE_NONE) ? ' NOT ' : '';

        $separator = ($jointype === datafilter::JOINTYPE_ALL) ? ' AND ' : ' OR ';

        // Build the SQL.

        $sql = ' FROM {question} q ' . implode(' ', $joins);

        $sql .= ' WHERE q.parent = 0 AND ' . $latestversion;

        if (!empty($conditions)) {

            $sql .= ' AND ' . $nonecondition . ' ( ';

            $sql .= implode($separator, $conditions);

            $sql .= ' ) ';

        }

        $this->countsql = 'SELECT count(1)' . $sql;

        $this->loadsql = 'SELECT ' . implode(', ', $fields) . $sql . ' ORDER BY ' . implode(', ', $sorts);

    }

    /**

     * Get the number of questions.

     *

     * @return int

     */

    public function get_question_count(): int {

        global $DB;

        if (is_null($this->totalcount)) {

            $this->totalcount = $DB->count_records_sql($this->countsql, $this->sqlparams);

        }

        return $this->totalcount;

    }

    /**

     * Load the questions we need to display.

     *

     * @return \moodle_recordset questionid => data about each question.

     */

    protected function load_page_questions(): \moodle_recordset {

        global $DB;

        $questions = $DB->get_recordset_sql($this->loadsql, $this->sqlparams,

            (int)$this->pagevars['qpage'] * (int)$this->pagevars['qperpage'], $this->pagevars['qperpage']);

        if (empty($questions)) {

            $questions->close();

            // No questions on this page. Reset to page 0.

            $questions = $DB->get_recordset_sql($this->loadsql, $this->sqlparams, 0, $this->pagevars['qperpage']);

        }

        return $questions;

    }

    /**

     * Returns the base url.

     *

     * @return \moodle_url

     */

    public function base_url(): \moodle_url {

        return $this->baseurl;

    }

    /**

     * Get the URL for editing a question as a moodle url.

     *

     * @param int $questionid the question id.

     * @return \moodle_url the URL, HTML-escaped.

     */

    public function edit_question_moodle_url($questionid) {

        return new \moodle_url($this->editquestionurl, ['id' => $questionid]);

    }

    /**

     * Get the URL for editing a question as a HTML-escaped string.

     *

     * @param int $questionid the question id.

     * @return string the URL, HTML-escaped.

     */

    public function edit_question_url($questionid) {

        return $this->edit_question_moodle_url($questionid)->out();

    }

    /**

     * Get the URL for duplicating a question as a moodle url.

     *

     * @param int $questionid the question id.

     * @return \moodle_url the URL.

     */

    public function copy_question_moodle_url($questionid) {

        return new \moodle_url($this->editquestionurl, ['id' => $questionid, 'makecopy' => 1]);

    }

    /**

     * Get the URL for duplicating a given question.

     * @param int $questionid the question id.

     * @return string the URL, HTML-escaped.

     */

    public function copy_question_url($questionid) {

        return $this->copy_question_moodle_url($questionid)->out();

    }

    /**

     * Get the context we are displaying the question bank for.

     * @return \context context object.

     */

    public function get_most_specific_context(): \context {

        return $this->contexts->lowest();

    }

    /**

     * @deprecated since Moodle 4.0

     */

    public function preview_question_url() {

        throw new coding_exception(__FUNCTION__ . '() has been removed.');

    }

    /**

     * Get fields from the pagevars array.

     *

     * If a field is specified, that particlar pagevars field will be returned. Otherwise the entire array will be returned.

     *

     * If a field is specified but it does not exist, null will be returned.

     *

     * @param ?string $field

     * @return mixed

     */

    public function get_pagevars(?string $field = null): mixed {

        if (is_null($field)) {

            return $this->pagevars;

        } else {

            return $this->pagevars[$field] ?? null;

        }

    }

    /**

     * Set the pagevars property with the provided array.

     *

     * @param array $pagevars

     */

    public function set_pagevars(array $pagevars): void {

        $this->pagevars = $pagevars;

    }

    /**

     * Shows the question bank interface.

     */

    public function display(): void {

        $editcontexts = $this->contexts->having_one_edit_tab_cap('questions');

        echo \html_writer::start_div('questionbankwindow boxwidthwide boxaligncenter', [

            'data-component' => 'core_question',

            'data-callback' => 'display_question_bank',

            'data-contextid' => $editcontexts[array_key_last($editcontexts)]->id,

        ]);

        // Show the filters and search options.

        $this->wanted_filters();

        // Continues with list of questions.

        $this->display_question_list();

        echo \html_writer::end_div();

    }

    /**

     * The filters for the question bank.

     */

    public function wanted_filters(): void {

        global $OUTPUT;

        [, $contextid] = explode(',', $this->pagevars['cat']);

        $catcontext = \context::instance_by_id($contextid);

        // Category selection form.

        $this->display_question_bank_header();

        // Add search conditions.

        $this->add_standard_search_conditions();

        // Render the question bank filters.

        $additionalparams = [

            'perpage' => $this->pagevars['qperpage'],

        ];

        $filter = new question_bank_filter_ui($catcontext, $this->searchconditions, $additionalparams, $this->component,

                $this->callback, static::class, 'qbank-table', $this->cm?->id, $this->pagevars,

                $this->extraparams);

        echo $OUTPUT->render($filter);

    }

    /**

     * Print the text if category id not available.

     *

     * @deprecated since Moodle 4.3 MDL-72321

     * @todo Final deprecation on Moodle 4.7 MDL-78090

     */

    protected function print_choose_category_message(): void {

        debugging(

            'Function print_choose_category_message() is deprecated, all the features for this method is currently ' .

                'handled by the qbank filter api, please have a look at ' .

                'question/bank/managecategories/classes/category_confition.php for more information.',

            DEBUG_DEVELOPER

        );

        echo \html_writer::start_tag('p', ['style' => "\"text-align:center;\""]);

        echo \html_writer::tag('b', get_string('selectcategoryabove', 'question'));

        echo \html_writer::end_tag('p');

    }

    /**

     * Gets current selected category.

     * @param string $categoryandcontext

     * @return false|mixed|\stdClass

     *

     * @deprecated since Moodle 4.3 MDL-72321

     * @todo Final deprecation on Moodle 4.7 MDL-78090

     */

    protected function get_current_category($categoryandcontext) {

        debugging(

            'Function get_current_category() is deprecated, all the features for this method is currently handled by ' .

            'the qbank filter api, please have a look at question/bank/managecategories/classes/category_confition.php ' .

            'for more information.',

            DEBUG_DEVELOPER

        );

        global $DB, $OUTPUT;

        list($categoryid, $contextid) = explode(',', $categoryandcontext);

        if (!$categoryid) {

            $this->print_choose_category_message();

            return false;

        }

        if (!$category = $DB->get_record('question_categories',

            ['id' => $categoryid, 'contextid' => $contextid])) {

            echo $OUTPUT->box_start('generalbox questionbank');

            echo $OUTPUT->notification('Category not found!');

            echo $OUTPUT->box_end();

            return false;

        }

        return $category;

    }

    /**

     * Display the form with options for which questions are displayed and how they are displayed.

     *

     * @param bool $showquestiontext Display the text of the question within the list.

     * @deprecated since Moodle 4.3 MDL-72321

     * @todo Final deprecation on Moodle 4.7 MDL-78090

     */