MDL-82587 mod_quiz: Add slot version updated event

mod/quiz/amd/src/question_slot.js

@@ -52,7 +52,7 @@ const registerEventListeners = () => {
         const slotId = e.target.dataset.slotId;
         const newVersion = parseInt(e.target.value);
 
-        setQuestionVersion(slotId, newVersion)
+        setQuestionVersion(slotId, newVersion === 0 ? null : newVersion)
             .then(() => {
                 location.reload();
                 return;
@@ -61,16 +61,9 @@ const registerEventListeners = () => {
     });
 };
 
-/** @property {Boolean} eventsRegistered If the event has been registered or not */
-let eventsRegistered = false;
-
 /**
  * Entrypoint of the js.
  */
 export const init = () => {
-    if (eventsRegistered) {
-        return;
-    }
-
     registerEventListeners();
 };

mod/quiz/classes/event/slot_version_updated.php

@@ -0,0 +1,107 @@
+<?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/>.
+
+declare(strict_types=1);
+
+namespace mod_quiz\event;
+
+use core\exception\coding_exception;
+use core\url;
+
+/**
+ * The question version of a slot has changed.
+ *
+ * @property-read array $other {
+ *      Extra information about event.
+ *
+ *      - int quizid: the id of the quiz.
+ *      - int previousversion: the previous question version.
+ *      - int newversion: the new question version.
+ * }
+ *
+ * @package   mod_quiz
+ * @copyright 2024 Catalyst IT Australia Pty Ltd
+ * @author    Cameron Ball <[email protected]>
+ * @license   https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class slot_version_updated extends \core\event\base {
+
+    #[\Override]
+    protected function init(): void {
+        $this->data['objecttable'] = 'quiz_slots';
+        $this->data['crud'] = 'u';
+        $this->data['edulevel'] = self::LEVEL_TEACHING;
+    }
+
+    #[\Override]
+    public static function get_name(): string {
+        return get_string('eventslotversionupdated', 'mod_quiz');
+    }
+
+    #[\Override]
+    public function get_description(): string {
+        $previousversion = $this->other['previousversion'] ?? 'Always latest';
+        $newversion = $this->other['newversion'] ?? 'Always latest';
+        return "The user with id '$this->userid' updated the slot with id '{$this->objectid}' " .
+            "belonging to the quiz with course module id '$this->contextinstanceid'. " .
+            "Its question version was changed from '$previousversion' to '$newversion'.";
+    }
+
+    #[\Override]
+    public function get_url(): url {
+        return new url('/mod/quiz/edit.php', ['cmid' => $this->contextinstanceid]);
+    }
+
+    #[\Override]
+    protected function validate_data(): void {
+        parent::validate_data();
+
+        if (!isset($this->objectid)) {
+            throw new coding_exception('The \'objectid\' value must be set.');
+        }
+
+        if (!isset($this->contextinstanceid)) {
+            throw new coding_exception('The \'contextinstanceid\' value must be set.');
+        }
+
+        if (!isset($this->other['quizid'])) {
+            throw new coding_exception('The \'quizid\' value must be set in other.');
+        }
+
+        // The value of previousversion and newversion can be null, so we check if
+        // the array key exists.
+        if (!array_key_exists('previousversion', $this->other)) {
+            throw new coding_exception('The \'previousversion\' value must be set in other.');
+        }
+
+        if (!array_key_exists('newversion', $this->other)) {
+            throw new coding_exception('The \'newversion\' value must be set in other.');
+        }
+    }
+
+    #[\Override]
+    public static function get_objectid_mapping(): array {
+        return ['db' => 'quiz_slots', 'restore' => 'quiz_question_instance'];
+    }
+
+    #[\Override]
+    public static function get_other_mapping(): array {
+        $othermapped = [];
+        $othermapped['quizid'] = ['db' => 'quiz', 'restore' => 'quiz'];
+
+        return $othermapped;
+    }
+}

mod/quiz/classes/external/submit_question_version.php

@@ -22,11 +22,12 @@
 require_once($CFG->dirroot . '/question/engine/datalib.php');
 require_once($CFG->libdir . '/questionlib.php');
 
+use core\context\module;
 use core_external\external_api;
 use core_external\external_function_parameters;
 use core_external\external_single_structure;
 use core_external\external_value;
-use stdClass;
+use mod_quiz\quiz_settings;
 
 /**
  * External api for changing the question version in the quiz.
@@ -45,46 +46,35 @@ class submit_question_version extends external_api {
      */
     public static function execute_parameters(): external_function_parameters {
         return new external_function_parameters([
-            'slotid' => new external_value(PARAM_INT, ''),
-            'newversion' => new external_value(PARAM_INT, '')
+            'slotid' => new external_value(PARAM_INT),
+            'newversion' => new external_value(PARAM_INT),
         ]);
     }
 
     /**
      * Set the questions slot parameters to display the question template.
      *
-     * @param int $slotid Slot id to display.
-     * @param int $newversion the version to set. 0 means 'always latest'.
+     * @param int $slotid Slot ID to display.
+     * @param int|null $newversion The version to set. Passing null means 'always latest'.
+     *                             For historical reasons, 0 also means 'always latest'.
      * @return array
      */
-    public static function execute(int $slotid, int $newversion): array {
+    public static function execute(int $slotid, ?int $newversion): array {
         global $DB;
-        $params = [
-            'slotid' => $slotid,
-            'newversion' => $newversion
-        ];
-        $params = self::validate_parameters(self::execute_parameters(), $params);
-        $response = [];
-        // Get the required data.
-        $referencedata = $DB->get_record('question_references',
-            ['itemid' => $params['slotid'], 'component' => 'mod_quiz', 'questionarea' => 'slot']);
-        $slotdata = $DB->get_record('quiz_slots', ['id' => $slotid]);
+        $params = self::validate_parameters(self::execute_parameters(), ['slotid' => $slotid, 'newversion' => $newversion]);
+        $slot = $DB->get_record('quiz_slots', ['id' => $slotid], '*', MUST_EXIST);
 
-        // Capability check.
-        [, $cm] = get_course_and_cm_from_instance($slotdata->quizid, 'quiz');
-        $context = \context_module::instance($cm->id);
+        $context = module::instance(get_course_and_cm_from_instance($slot->quizid, 'quiz')[1]->id);
         self::validate_context($context);
         require_capability('mod/quiz:manage', $context);
 
-        $reference = new stdClass();
-        $reference->id = $referencedata->id;
-        if ($params['newversion'] === 0) {
-            $reference->version = null;
-        } else {
-            $reference->version = $params['newversion'];
-        }
-        $response['result'] = $DB->update_record('question_references', $reference);
-        return $response;
+        $quizobj = quiz_settings::create($slot->quizid);
+
+        // This WS historically (and wrongly) accepted 0 to mean 'always latest'. The correct behaviour
+        // is that null implies awlays latest. To preserve backwards compatibility, we continue to accept
+        // 0, but just turn it in to null before passing to the appropriate API. See: MDL-82587.
+        $newversionnormalised = $params['newversion'] === 0 ? null : $params['newversion'];
+        return ['result' => $quizobj->get_structure()->update_slot_version($slot->id, $newversionnormalised)];
     }
 
     /**

mod/quiz/classes/output/edit_renderer.php

@@ -521,6 +521,8 @@ public function questions_in_section(structure $structure, $section,
         foreach ($structure->get_slots_in_section($section->id) as $slot) {
             $output .= $this->question_row($structure, $slot, $contexts, $pagevars, $pageurl);
         }
+
+        $this->page->requires->js_call_amd('mod_quiz/question_slot', 'init');
         return html_writer::tag('ul', $output, ['class' => 'section img-text']);
     }
 
@@ -776,7 +778,6 @@ public function question(structure $structure, int $slot, \moodle_url $pageurl)
         if ($structure->get_slot_by_number($slot)->qtype !== 'random') {
             $data['versionselection'] = true;
             $data['versionoption'] = $structure->get_version_choices_for_slot($slot);
-            $this->page->requires->js_call_amd('mod_quiz/question_slot', 'init', [$slotid]);
         }
 
         // Render the question slot template.

mod/quiz/classes/structure.php

@@ -24,6 +24,7 @@
 use mod_quiz\event\quiz_grade_item_updated;
 use mod_quiz\event\slot_grade_item_updated;
 use mod_quiz\event\slot_mark_updated;
+use mod_quiz\event\slot_version_updated;
 use mod_quiz\question\bank\qbank_helper;
 use mod_quiz\question\qubaids_for_quiz;
 use stdClass;
@@ -1168,6 +1169,56 @@ public function update_slot_maxmark($slot, $maxmark) {
         return true;
     }
 
+    /**
+     * Update the question version for a given slot, if necessary.
+     *
+     * @param int $id ID of row from the quiz_slots table.
+     * @param int|null $newversion The new question version for the slot.
+     *                             A null value means 'Always latest'.
+     * @return bool True if the version was updated, false if no update was required.
+     * @throws coding_exception If the specified version does not exist.
+     */
+    public function update_slot_version(int $id, ?int $newversion): bool {
+        global $DB;
+
+        $slot = $this->get_slot_by_id($id);
+        $context = $this->quizobj->get_context();
+        $refparams = ['usingcontextid' => $context->id, 'component' => 'mod_quiz', 'questionarea' => 'slot', 'itemid' => $slot->id];
+        $reference = $DB->get_record('question_references', $refparams, '*', MUST_EXIST);
+        $oldversion = is_null($reference->version) ? null : (int) $reference->version;
+        $reference->version = $newversion === 0 ? null : $newversion;
+        $existsparams = ['questionbankentryid' => $reference->questionbankentryid, 'version' => $newversion];
+        $versionexists = $DB->record_exists('question_versions', $existsparams);
+
+        // We are attempting to switch to an existing version.
+        // Verify that the version we want to switch to exists.
+        if (!is_null($newversion) && !$versionexists) {
+            throw new coding_exception(
+                'Version: ' . $newversion . ' ' .
+                'does not exist for question bank entry: ' . $reference->questionbankentryid
+            );
+        }
+
+        if ($newversion === $oldversion) {
+            return false;
+        }
+
+        $transaction = $DB->start_delegated_transaction();
+        $DB->update_record('question_references', $reference);
+        slot_version_updated::create([
+            'context' => $this->quizobj->get_context(),
+            'objectid' => $slot->id,
+            'other' => [
+                'quizid' => $this->get_quizid(),
+                'previousversion' => $oldversion,
+                'newversion' => $reference->version,
+            ],
+        ])->trigger();
+        $transaction->allow_commit();
+
+        return true;
+    }
+
     /**
      * Change which grade this slot contributes to, for quizzes with multiple grades.
      *

mod/quiz/lang/en/quiz.php

@@ -390,6 +390,7 @@
 $string['eventslotdisplayedquestionnumberupdated'] = 'Slot displayed question number updated';
 $string['eventslotgradeitemupdated'] = 'Slot grade item updated';
 $string['eventslotmarkupdated'] = 'Slot mark updated';
+$string['eventslotversionupdated'] = 'Slot version updated';
 $string['eventslotmoved'] = 'Slot moved';
 $string['eventslotrequirepreviousupdated'] = 'Slot require previous updated';
 $string['everynquestions'] = 'Every {$a} questions';