From 912b5d9713aa006299b94b7697995f08403e6343 Mon Sep 17 00:00:00 2001
From: Sebastian <sebastian@sgundersen.com>
Date: Mon, 25 Mar 2024 04:15:58 +0100
Subject: [PATCH] Code cleanup and fixing CI errors

---
 .github/workflows/moodle-ci.yml               |   2 +-
 ajax.php                                      | 246 +++++++++---------
 amd/build.sh                                  |  11 -
 .../backup_jazzquiz_activity_task.class.php   |   4 +
 backup/moodle2/backup_jazzquiz_stepslib.php   |  24 +-
 .../restore_jazzquiz_activity_task.class.php  |   8 +-
 backup/moodle2/restore_jazzquiz_stepslib.php  |   9 +-
 classes/bank/add_questions_bank_view.php      |  57 ++++
 classes/bank/jazzquiz_question_bank_view.php  | 213 ---------------
 ...ion_bank_add_to_jazzquiz_action_column.php |  68 -----
 classes/exporter.php                          |  30 ++-
 classes/forms/view/start_session.php          |  23 +-
 classes/improviser.php                        | 134 +++++-----
 classes/jazzquiz.php                          | 183 +++++++------
 classes/jazzquiz_attempt.php                  | 227 ++++++++++------
 classes/jazzquiz_question.php                 |  20 +-
 classes/jazzquiz_session.php                  | 223 ++++++++--------
 classes/jazzquiz_vote.php                     |  28 +-
 classes/local/page_requirements_diff.php      |  79 ++++++
 classes/output/renderer.php                   | 196 +++++---------
 classes/privacy/provider.php                  |  54 ++--
 db/access.php                                 |  51 ++--
 db/upgrade.php                                |   9 +-
 edit.php                                      |  84 ++----
 index.php                                     |  12 +-
 lang/en/jazzquiz.php                          |   3 +-
 lib.php                                       |  46 ++--
 locallib.php                                  |  11 +-
 reports.php                                   |  26 +-
 styles.css                                    |  44 +---
 templates/continue_session.mustache           |  29 ++-
 templates/edit_question_list.mustache         | 126 +++++----
 templates/guests_not_allowed.mustache         |  30 ++-
 templates/join_session.mustache               |  44 +++-
 templates/no_session.mustache                 |  31 ++-
 templates/question.mustache                   |  43 ++-
 templates/quiz.mustache                       |  58 ++++-
 templates/report.mustache                     | 147 ++++++++---
 templates/start_session.mustache              |  31 ++-
 view.php                                      |  75 ++----
 40 files changed, 1376 insertions(+), 1363 deletions(-)
 delete mode 100755 amd/build.sh
 create mode 100644 classes/bank/add_questions_bank_view.php
 delete mode 100755 classes/bank/jazzquiz_question_bank_view.php
 delete mode 100755 classes/bank/question_bank_add_to_jazzquiz_action_column.php
 create mode 100644 classes/local/page_requirements_diff.php

diff --git a/.github/workflows/moodle-ci.yml b/.github/workflows/moodle-ci.yml
index 070b8b2..1c0819b 100644
--- a/.github/workflows/moodle-ci.yml
+++ b/.github/workflows/moodle-ci.yml
@@ -98,7 +98,7 @@ jobs:
 
       - name: Grunt
         if: ${{ !cancelled() }}
-        run: moodle-plugin-ci grunt --max-lint-warnings 0
+        run: moodle-plugin-ci grunt --max-lint-warnings 11 # For now just make sure we don't get more warnings.
 
       - name: PHPUnit tests
         if: ${{ !cancelled() }}
diff --git a/ajax.php b/ajax.php
index 416a4c5..1429ead 100755
--- a/ajax.php
+++ b/ajax.php
@@ -27,6 +27,8 @@
 
 namespace mod_jazzquiz;
 
+use question_bank;
+
 define('AJAX_SCRIPT', true);
 
 require_once('../../config.php');
@@ -39,18 +41,17 @@
 
 /**
  * Send a list of all the questions tagged for use with improvisation.
+ *
  * @param jazzquiz $jazzquiz
- * @return mixed[]
+ * @return array
  */
-function show_all_improvise_questions(jazzquiz $jazzquiz) {
+function show_all_improvise_questions(jazzquiz $jazzquiz): array {
     $improviser = new improviser($jazzquiz);
     $questionrecords = $improviser->get_all_improvised_question_definitions();
-    debugging( 'show'.$questionrecords );
     if (!$questionrecords) {
-        debugging( 'No improvisation questions' );
         return [
             'status' => 'error',
-            'message' => 'No improvisation questions'
+            'message' => 'No improvisation questions',
         ];
     }
     $questions = [];
@@ -59,21 +60,22 @@ function show_all_improvise_questions(jazzquiz $jazzquiz) {
             'questionid' => $question->id,
             'jazzquizquestionid' => 0,
             'name' => str_replace('{IMPROV}', '', $question->name),
-            'time' => $jazzquiz->data->defaultquestiontime
+            'time' => $jazzquiz->data->defaultquestiontime,
         ];
     }
     return [
         'status' => 'success',
-        'questions' => $questions
+        'questions' => $questions,
     ];
 }
 
 /**
  * Send a list of all the questions added to the quiz.
+ *
  * @param jazzquiz $jazzquiz
- * @return mixed[]
+ * @return array
  */
-function show_all_jump_questions(jazzquiz $jazzquiz) {
+function show_all_jump_questions(jazzquiz $jazzquiz): array {
     global $DB;
     $sql = 'SELECT q.id AS id, q.name AS name, jq.questiontime AS time, jq.id AS jqid';
     $sql .= '  FROM {jazzquiz_questions} jq';
@@ -87,21 +89,22 @@ function show_all_jump_questions(jazzquiz $jazzquiz) {
             'questionid' => $question->id,
             'jazzquizquestionid' => $question->jqid,
             'name' => $question->name,
-            'time' => $question->time
+            'time' => $question->time,
         ];
     }
     return [
         'status' => 'success',
-        'questions' => $questions
+        'questions' => $questions,
     ];
 }
 
 /**
  * Get the form for the current question.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function get_question_form(jazzquiz_session $session) {
+function get_question_form(jazzquiz_session $session): array {
     $session->load_session_questions();
     $slot = optional_param('slot', 0, PARAM_INT);
     if ($slot === 0) {
@@ -111,12 +114,12 @@ function get_question_form(jazzquiz_session $session) {
     $js = '';
     $css = [];
     $isalreadysubmitted = true;
-    if (!$session->attempt->has_responded($slot)) {
+    if (!$session->myattempt->has_responded($slot)) {
         $jazzquiz = $session->jazzquiz;
         /** @var output\renderer $renderer */
         $renderer = $jazzquiz->renderer;
         $isinstructor = $jazzquiz->is_instructor();
-        list($html, $js, $css) = $renderer->render_question_form($slot, $session->attempt, $jazzquiz, $isinstructor);
+        list($html, $js, $css) = $renderer->render_question_form($slot, $session->myattempt, $jazzquiz, $isinstructor);
         $isalreadysubmitted = false;
     }
     $qtype = $session->get_question_type_by_slot($slot);
@@ -127,16 +130,17 @@ function get_question_form(jazzquiz_session $session) {
         'css' => $css,
         'question_type' => $qtype,
         'is_already_submitted' => $isalreadysubmitted,
-        'voteable' => !in_array($qtype, $voteable)
+        'voteable' => !in_array($qtype, $voteable),
     ];
 }
 
 /**
  * Start a new question.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function start_question(jazzquiz_session $session) {
+function start_question(jazzquiz_session $session): array {
     $session->load_session_questions();
     $session->load_attempts();
     $method = required_param('method', PARAM_ALPHA);
@@ -148,7 +152,9 @@ function start_question(jazzquiz_session $session) {
             $jazzquizquestionid = optional_param('jazzquizquestionid', 0, PARAM_INT);
             if ($jazzquizquestionid !== 0) {
                 $jazzquizquestion = $session->jazzquiz->get_question_by_id($jazzquizquestionid);
-                $session->data->slot = $jazzquizquestion->data->slot;
+                if ($jazzquizquestion) {
+                    $session->data->slot = $jazzquizquestion->data->slot;
+                }
             }
             break;
         case 'repoll':
@@ -156,7 +162,7 @@ function start_question(jazzquiz_session $session) {
             if ($lastslot === 0) {
                 return [
                     'status' => 'error',
-                    'message' => 'Nothing to repoll.'
+                    'message' => 'Nothing to repoll.',
                 ];
             }
             $questionid = $session->questions[$lastslot]->questionid;
@@ -167,7 +173,7 @@ function start_question(jazzquiz_session $session) {
             if ($session->data->slot >= $lastslot) {
                 return [
                     'status' => 'error',
-                    'message' => 'No next question.'
+                    'message' => 'No next question.',
                 ];
             }
             $session->data->slot++;
@@ -190,7 +196,7 @@ function start_question(jazzquiz_session $session) {
         default:
             return [
                 'status' => 'error',
-                'message' => "Invalid method $method"
+                'message' => "Invalid method $method",
             ];
     }
     list($success, $questiontime) = $session->start_question($questionid, $questiontime);
@@ -207,20 +213,21 @@ function start_question(jazzquiz_session $session) {
     return [
         'status' => 'success',
         'questiontime' => $questiontime,
-        'delay' => $session->data->nextstarttime - time()
+        'delay' => $session->data->nextstarttime - time(),
     ];
 }
 
 /**
  * Start the quiz.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function start_quiz(jazzquiz_session $session) {
+function start_quiz(jazzquiz_session $session): array {
     if ($session->data->status !== 'notrunning') {
         return [
             'status' => 'error',
-            'message' => 'Quiz is already running'
+            'message' => 'Quiz is already running',
         ];
     }
     $session->data->status = 'preparing';
@@ -230,15 +237,16 @@ function start_quiz(jazzquiz_session $session) {
 
 /**
  * Submit a response for the current question.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function save_question(jazzquiz_session $session) {
-    $attempt = $session->attempt;
+function save_question(jazzquiz_session $session): array {
+    $attempt = $session->myattempt;
     if (!$attempt->belongs_to_current_user()) {
         return [
             'status' => 'error',
-            'message' => 'Invalid user'
+            'message' => 'Invalid user',
         ];
     }
     $session->load_session_questions();
@@ -251,22 +259,23 @@ function save_question(jazzquiz_session $session) {
     }
     return [
         'status' => 'success',
-        'feedback' => $feedback
+        'feedback' => $feedback,
     ];
 }
 
 /**
  * Start a vote.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function run_voting(jazzquiz_session $session) {
+function run_voting(jazzquiz_session $session): array {
     $questions = required_param('questions', PARAM_RAW);
     $questions = json_decode(urldecode($questions), true);
     if (!$questions) {
         return [
             'status' => 'error',
-            'message' => 'Failed to decode questions'
+            'message' => 'Failed to decode questions',
         ];
     }
     $qtype = optional_param('question_type', '', PARAM_ALPHANUM);
@@ -283,10 +292,11 @@ function run_voting(jazzquiz_session $session) {
 
 /**
  * Save a vote.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function save_vote(jazzquiz_session $session) {
+function save_vote(jazzquiz_session $session): array {
     $voteid = required_param('vote', PARAM_INT);
     $vote = new jazzquiz_vote($session->data->id);
     $status = $vote->save_vote($voteid);
@@ -296,9 +306,9 @@ function save_vote(jazzquiz_session $session) {
 /**
  * Get the vote results.
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function get_vote_results(jazzquiz_session $session) {
+function get_vote_results(jazzquiz_session $session): array {
     $session->load_session_questions();
     $session->load_attempts();
     $slot = count($session->questions);
@@ -306,16 +316,17 @@ function get_vote_results(jazzquiz_session $session) {
     $votes = $vote->get_results();
     return [
         'answers' => $votes,
-        'total_students' => $session->get_student_count()
+        'total_students' => $session->get_student_count(),
     ];
 }
 
 /**
  * End the current question.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function end_question($session) {
+function end_question(jazzquiz_session $session): array {
     $session->data->status = 'reviewing';
     $session->save();
     return ['status' => 'success'];
@@ -323,20 +334,22 @@ function end_question($session) {
 
 /**
  * Get the correct answer for the current question.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function get_right_response(jazzquiz_session $session) {
+function get_right_response(jazzquiz_session $session): array {
     $session->load_session_questions();
     return ['right_answer' => $session->get_question_right_response()];
 }
 
 /**
  * Close a session.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function close_session(jazzquiz_session $session) {
+function close_session(jazzquiz_session $session): array {
     $session->load_attempts();
     $session->end_session();
     return ['status' => 'success'];
@@ -344,10 +357,11 @@ function close_session(jazzquiz_session $session) {
 
 /**
  * Get the results for a session.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function get_results(jazzquiz_session $session) {
+function get_results(jazzquiz_session $session): array {
     $session->load_session_questions();
     $session->load_attempts();
     $slot = count($session->questions);
@@ -365,16 +379,17 @@ function get_results(jazzquiz_session $session) {
         'responses' => $results['responses'],
         'responded' => $results['responded'],
         'total_students' => $results['student_count'],
-        'merge_count' => $mergecount
+        'merge_count' => $mergecount,
     ];
 }
 
 /**
  * Merge a response into another.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function merge_responses(jazzquiz_session $session) {
+function merge_responses(jazzquiz_session $session): array {
     $session->load_session_questions();
     $slot = optional_param('slot', count($session->questions), PARAM_INT);
     if (!isset($session->questions[$slot])) {
@@ -388,10 +403,11 @@ function merge_responses(jazzquiz_session $session) {
 
 /**
  * Undo the last merge.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function undo_merge(jazzquiz_session $session) {
+function undo_merge(jazzquiz_session $session): array {
     $session->load_session_questions();
     $slot = optional_param('slot', count($session->questions), PARAM_INT);
     if (!isset($session->questions[$slot])) {
@@ -403,9 +419,10 @@ function undo_merge(jazzquiz_session $session) {
 
 /**
  * Convert STACK (Maxima) string to LaTeX format.
- * @return mixed[]
+ *
+ * @return array
  */
-function stack_to_latex() {
+function stack_to_latex(): array {
     global $DB;
     $input = required_param('input', PARAM_RAW);
     $input = urldecode($input);
@@ -414,28 +431,29 @@ function stack_to_latex() {
         return [
             'message' => 'STACK question not found.',
             'latex' => $input,
-            'original' => $input
+            'original' => $input,
         ];
     }
 
     /** @var \qtype_stack_question $question */
-    $question = \question_bank::load_question($question->id);
+    $question = question_bank::load_question($question->id);
     $question->initialise_question_from_seed();
     $state = $question->get_input_state('ans1', ['ans1' => $input]);
     $latex = $state->contentsdisplayed;
 
     return [
         'latex' => $latex,
-        'original' => $input
+        'original' => $input,
     ];
 }
 
 /**
  * Retrieve the current state of the session.
+ *
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function session_info(jazzquiz_session $session) {
+function session_info(jazzquiz_session $session): array {
     global $DB;
     switch ($session->data->status) {
         // Just a generic response with the state.
@@ -445,7 +463,7 @@ function session_info(jazzquiz_session $session) {
                 $session->load_attempts();
                 return [
                     'status' => $session->data->status,
-                    'student_count' => $session->get_student_count()
+                    'student_count' => $session->get_student_count(),
                 ];
             }
             // Fall-through.
@@ -453,7 +471,7 @@ function session_info(jazzquiz_session $session) {
         case 'reviewing':
             return [
                 'status' => $session->data->status,
-                'slot' => $session->data->slot // For the preplanned questions.
+                'slot' => $session->data->slot, // For the preplanned questions.
             ];
 
         case 'voting':
@@ -466,7 +484,7 @@ function session_info(jazzquiz_session $session) {
                     'text' => $voteoption->attempt,
                     'id' => $voteoption->id,
                     'question_type' => $voteoption->qtype,
-                    'content_id' => "vote_answer_label_$i"
+                    'content_id' => "vote_answer_label_$i",
                 ];
                 $html .= '<label>';
                 $html .= '<input class="jazzquiz-select-vote" type="radio" name="vote" value="' . $voteoption->id . '">';
@@ -479,7 +497,7 @@ function session_info(jazzquiz_session $session) {
             return [
                 'status' => 'voting',
                 'html' => $html,
-                'options' => $options
+                'options' => $options,
             ];
 
         // Send the currently active question.
@@ -487,87 +505,69 @@ function session_info(jazzquiz_session $session) {
             return [
                 'status' => 'running',
                 'questiontime' => $session->data->currentquestiontime,
-                'delay' => $session->data->nextstarttime - time()
+                'delay' => $session->data->nextstarttime - time(),
             ];
 
         // This should not be reached, but if it ever is, let's just assume the quiz is not running.
         default:
             return [
                 'status' => 'notrunning',
-                'message' => 'Unknown error. State: ' . $session->data->status
+                'message' => 'Unknown error. State: ' . $session->data->status,
             ];
     }
 }
 
 /**
  * Handle an instructor request.
+ *
  * @param string $action
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function handle_instructor_request(string $action, jazzquiz_session $session) : array {
-    switch ($action) {
-        case 'start_quiz':
-            return start_quiz($session);
-        case 'get_question_form':
-            return get_question_form($session);
-        case 'save_question':
-            return save_question($session);
-        case 'list_improvise_questions':
-            return show_all_improvise_questions($session->jazzquiz);
-        case 'list_jump_questions':
-            return show_all_jump_questions($session->jazzquiz);
-        case 'run_voting':
-            return run_voting($session);
-        case 'get_vote_results':
-            return get_vote_results($session);
-        case 'get_results':
-            return get_results($session);
-        case 'start_question':
-            return start_question($session);
-        case 'end_question':
-            return end_question($session);
-        case 'get_right_response':
-            return get_right_response($session);
-        case 'merge_responses':
-            return merge_responses($session);
-        case 'undo_merge':
-            return undo_merge($session);
-        case 'close_session':
-            return close_session($session);
-        case 'info':
-            return session_info($session);
-        default:
-            return ['status' => 'error', 'message' => 'Invalid action'];
-    }
+function handle_instructor_request(string $action, jazzquiz_session $session): array {
+    return match ($action) {
+        'start_quiz' => start_quiz($session),
+        'get_question_form' => get_question_form($session),
+        'save_question' => save_question($session),
+        'list_improvise_questions' => show_all_improvise_questions($session->jazzquiz),
+        'list_jump_questions' => show_all_jump_questions($session->jazzquiz),
+        'run_voting' => run_voting($session),
+        'get_vote_results' => get_vote_results($session),
+        'get_results' => get_results($session),
+        'start_question' => start_question($session),
+        'end_question' => end_question($session),
+        'get_right_response' => get_right_response($session),
+        'merge_responses' => merge_responses($session),
+        'undo_merge' => undo_merge($session),
+        'close_session' => close_session($session),
+        'info' => session_info($session),
+        default => ['status' => 'error', 'message' => 'Invalid action'],
+    };
 }
 
 /**
  * Handle a student request.
+ *
  * @param string $action
  * @param jazzquiz_session $session
- * @return mixed[]
+ * @return array
  */
-function handle_student_request(string $action, jazzquiz_session $session) : array {
-    switch ($action) {
-        case 'save_question':
-            return save_question($session);
-        case 'save_vote':
-            return save_vote($session);
-        case 'get_question_form':
-            return get_question_form($session);
-        case 'info':
-            return session_info($session);
-        default:
-            return ['status' => 'error', 'message' => 'Invalid action'];
-    }
+function handle_student_request(string $action, jazzquiz_session $session): array {
+    return match ($action) {
+        'save_question' => save_question($session),
+        'save_vote' => save_vote($session),
+        'get_question_form' => get_question_form($session),
+        'info' => session_info($session),
+        default => ['status' => 'error', 'message' => 'Invalid action'],
+    };
 }
 
 /**
  * The entry point to handle instructor and student actions.
- * @return mixed[]
+ *
+ * @return array
  */
-function jazzquiz_ajax() {
+function jazzquiz_ajax(): array {
     $action = required_param('action', PARAM_ALPHANUMEXT);
 
     // TODO: Better solution if more non-session actions are added.
@@ -583,21 +583,21 @@ function jazzquiz_ajax() {
     if (!$session->data->sessionopen) {
         return [
             'status' => 'sessionclosed',
-            'message' => 'Session is closed'
+            'message' => 'Session is closed',
         ];
     }
 
-    $session->load_attempt();
-    if (!$session->attempt) {
+    $session->load_my_attempt();
+    if (!$session->myattempt) {
         return [
             'status' => 'error',
-            'message' => 'No attempt found'
+            'message' => 'No attempt found',
         ];
     }
-    if (!$session->attempt->is_active()) {
+    if (!$session->myattempt->is_active()) {
         return [
             'status' => 'error',
-            'message' => 'This attempt is not in progress'
+            'message' => 'This attempt is not in progress',
         ];
     }
 
diff --git a/amd/build.sh b/amd/build.sh
deleted file mode 100755
index a9c5431..0000000
--- a/amd/build.sh
+++ /dev/null
@@ -1,11 +0,0 @@
-#!/bin/bash
-echo 'Copying...'
-cp -R src orig
-echo 'Running Babel...'
-babel orig -d src
-echo 'Running Grunt...'
-grunt amd --force
-echo 'Cleaning up...'
-rm -R src
-mv orig src
-echo 'Done.'
diff --git a/backup/moodle2/backup_jazzquiz_activity_task.class.php b/backup/moodle2/backup_jazzquiz_activity_task.class.php
index 11107dd..f9badac 100644
--- a/backup/moodle2/backup_jazzquiz_activity_task.class.php
+++ b/backup/moodle2/backup_jazzquiz_activity_task.class.php
@@ -20,6 +20,10 @@
 
 /**
  * Backup task that provides all the settings and steps to perform one complete backup.
+ *
+ * @package   mod_jazzquiz
+ * @copyright 2024 NTNU
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class backup_jazzquiz_activity_task extends backup_activity_task {
 
diff --git a/backup/moodle2/backup_jazzquiz_stepslib.php b/backup/moodle2/backup_jazzquiz_stepslib.php
index 3eec4dd..ff0c440 100644
--- a/backup/moodle2/backup_jazzquiz_stepslib.php
+++ b/backup/moodle2/backup_jazzquiz_stepslib.php
@@ -14,10 +14,12 @@
 // 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();
-
 /**
  * Define the complete choice structure for backup, with file and id annotations.
+ *
+ * @package   mod_jazzquiz
+ * @copyright 2024 NTNU
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class backup_jazzquiz_activity_structure_step extends backup_questions_activity_structure_step {
 
@@ -36,14 +38,14 @@ protected function define_structure() {
             'defaultquestiontime',
             'waitforquestiontime',
             'cfganonymity',
-            'cfgallowguests'
+            'cfgallowguests',
         ]);
 
         $questions = new backup_nested_element('questions');
         $question = new backup_nested_element('question', ['id'], [
             'questionid',
             'questiontime',
-            'slot'
+            'slot',
         ]);
 
         $sessions = new backup_nested_element('sessions');
@@ -57,7 +59,7 @@ protected function define_structure() {
             'nextstarttime',
             'created',
             'anonymity',
-            'allowguests'
+            'allowguests',
         ]);
 
         $sessionquestions = new backup_nested_element('sessionquestions');
@@ -65,7 +67,7 @@ protected function define_structure() {
             'sessionid',
             'questionid',
             'questiontime',
-            'slot'
+            'slot',
         ]);
 
         $attempts = new backup_nested_element('attempts');
@@ -79,7 +81,7 @@ protected function define_structure() {
             'timestart',
             'timefinish',
             'timemodified',
-            'guestsession'
+            'guestsession',
         ]);
         $this->add_question_usages($attempt, 'questionengid');
 
@@ -89,7 +91,7 @@ protected function define_structure() {
             'slot',
             'ordernum',
             'original',
-            'merged'
+            'merged',
         ]);
 
         $votes = new backup_nested_element('votes');
@@ -100,14 +102,14 @@ protected function define_structure() {
             'finalcount',
             'userlist',
             'qtype',
-            'slot'
+            'slot',
         ]);
 
         $attendances = new backup_nested_element('attendances');
         $attendance = new backup_nested_element('attendance', ['id'], [
             'sessionid',
             'userid',
-            'numresponses'
+            'numresponses',
         ]);
 
         // Build the tree.
@@ -140,7 +142,7 @@ protected function define_structure() {
             $merge->set_source_table('jazzquiz_merges', ['sessionid' => backup::VAR_PARENTID]);
             $vote->set_source_table('jazzquiz_votes', [
                 'jazzquizid' => backup::VAR_ACTIVITYID,
-                'sessionid' => backup::VAR_PARENTID
+                'sessionid' => backup::VAR_PARENTID,
             ]);
         }
 
diff --git a/backup/moodle2/restore_jazzquiz_activity_task.class.php b/backup/moodle2/restore_jazzquiz_activity_task.class.php
index 1d82d86..89d88b4 100644
--- a/backup/moodle2/restore_jazzquiz_activity_task.class.php
+++ b/backup/moodle2/restore_jazzquiz_activity_task.class.php
@@ -21,6 +21,10 @@
 /**
  * JazzQuiz restore task that provides all the settings and steps to perform one
  * complete restore of the activity
+ *
+ * @package   mod_jazzquiz
+ * @copyright 2024 NTNU
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class restore_jazzquiz_activity_task extends restore_activity_task {
 
@@ -43,7 +47,7 @@ protected function define_my_steps() {
      */
     public static function define_decode_contents() {
         return [
-            new restore_decode_content('jazzquiz', ['intro'])
+            new restore_decode_content('jazzquiz', ['intro']),
         ];
     }
 
@@ -53,7 +57,7 @@ public static function define_decode_contents() {
     public static function define_decode_rules() {
         return [
             new restore_decode_rule('JAZZQUIZVIEWBYID', '/mod/jazzquiz/view.php?id=$1', 'course_module'),
-            new restore_decode_rule('JAZZQUIZINDEX', '/mod/jazzquiz/index.php?id=$1', 'course')
+            new restore_decode_rule('JAZZQUIZINDEX', '/mod/jazzquiz/index.php?id=$1', 'course'),
         ];
     }
 
diff --git a/backup/moodle2/restore_jazzquiz_stepslib.php b/backup/moodle2/restore_jazzquiz_stepslib.php
index 57f5cf3..efe9046 100644
--- a/backup/moodle2/restore_jazzquiz_stepslib.php
+++ b/backup/moodle2/restore_jazzquiz_stepslib.php
@@ -14,8 +14,13 @@
 // 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();
-
+/**
+ * Restore Jazzquiz from backup.
+ *
+ * @package   mod_jazzquiz
+ * @copyright 2024 NTNU
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
 class restore_jazzquiz_activity_structure_step extends restore_questions_activity_structure_step {
 
     /**
diff --git a/classes/bank/add_questions_bank_view.php b/classes/bank/add_questions_bank_view.php
new file mode 100644
index 0000000..3bc049a
--- /dev/null
+++ b/classes/bank/add_questions_bank_view.php
@@ -0,0 +1,57 @@
+<?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/>.
+
+/**
+ * Question bank view for managing JazzQuiz questions.
+ *
+ * @package mod_jazzquiz
+ * @copyright 2024 NTNU
+ * @author Sebastian Gundersen <sebastian@sgundersen.com>
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace mod_jazzquiz\bank;
+
+use context;
+
+/**
+ * Displays a button at the bottom of the question bank view, which allows the user
+ * to add the selected questions from the question bank list to the JazzQuiz question list.
+ *
+ * @package mod_jazzquiz
+ * @copyright 2024 NTNU
+ * @author Sebastian Gundersen <sebastian@sgundersen.com>
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class add_questions_bank_view extends \core_question\local\bank\view {
+
+    /**
+     * Display button to add selected questions to the quiz.
+     *
+     * @param context $catcontext
+     * @return void
+     */
+    protected function display_bottom_controls(context $catcontext): void {
+        echo '<div class="pt-2">';
+        if (has_capability('moodle/question:useall', $catcontext)) {
+            echo '<button class="btn btn-primary jazzquiz-add-selected-questions">';
+            echo get_string('addselectedquestionstoquiz', 'quiz');
+            echo '</button>';
+        }
+        echo '</div>';
+    }
+
+}
diff --git a/classes/bank/jazzquiz_question_bank_view.php b/classes/bank/jazzquiz_question_bank_view.php
deleted file mode 100755
index 043130d..0000000
--- a/classes/bank/jazzquiz_question_bank_view.php
+++ /dev/null
@@ -1,213 +0,0 @@
-<?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/>.
-
-/**
- * Defines the class for rendering the question bank for the edit page.
- *
- * @package     mod_jazzquiz
- * @author      John Hoopes <moodle@madisoncreativeweb.com>
- * @copyright   2014 University of Wisconsin - Madison
- * @copyright   2018 NTNU
- * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
-
-namespace mod_jazzquiz\bank;
-
-defined('MOODLE_INTERNAL') || die();
-
-use \core_question\bank\search\tag_condition as tag_condition;
-use \core_question\bank\search\hidden_condition as hidden_condition;
-use \core_question\bank\search\category_condition as category_condition;
-
-/**
- * Subclass of the question bank view class to change the way it works/looks
- *
- * @package     mod_jazzquiz
- * @author      John Hoopes <moodle@madisoncreativeweb.com>
- * @copyright   2014 University of Wisconsin - Madison
- * @copyright   2018 NTNU
- * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
-class jazzquiz_question_bank_view extends \core_question\local\bank\view {
-
-    /**
-     * Define the columns we want to be displayed on the question bank
-     * @return array
-     */
-    protected function wanted_columns(): array {
-        // Full class names for question bank columns.
-        $columns = [
-            '\\mod_jazzquiz\\bank\\question_bank_add_to_jazzquiz_action_column',
-            'core_question\\local\\bank\\checkbox_column',
-            'qbank_viewquestiontype\\question_type_column',
-            'qbank_viewquestionname\\viewquestionname_column_helper',
-            'qbank_previewquestion\\preview_action_column',
-        ];
-
-        // Needs to check qbshowtext parameter manually from baseurl in order
-        // to determine whether to display the question text row below questions
-        $queryparams = explode(';', $this->baseurl);
-        
-        foreach ($queryparams as $value) {
-            $value = str_replace('&', '', $value);
-            $value = str_replace('amp', '', $value);
-            $param = explode('=', $value);
-
-            if ($param[0] == 'qbshowtext') {
-                if ((int)$param[1] != 0) {
-                    array_push($columns, 'qbank_viewquestiontext\\question_text_row');
-                }
-                break;
-            }
-        } 
-
-
-
-        foreach ($columns as $column) {
-            $this->requiredcolumns[$column] = new $column($this);
-        }
-        return $this->requiredcolumns;
-    }
-
-    /**
-     * Shows the question bank editing interface.
-     * @param string $tabname
-     * @param array $pagevars
-     * @throws \coding_exception
-     */
-    public function display($pagevars, $tabname): void {
-        $page = $pagevars['qpage'];
-        $perpage = $pagevars['qperpage'];
-        $cat = $pagevars['cat'];
-        $recurse = $pagevars['recurse'];
-        $showhidden = $pagevars['showhidden'];
-        $showquestiontext = $pagevars['qbshowtext'];
-        $tagids = [];
-        if (!empty($pagevars['qtagids'])) {
-            $tagids = $pagevars['qtagids'];
-        }
-
-        global $PAGE;
-
-        $contexts = $this->contexts->having_one_edit_tab_cap($tabname);
-        list($categoryid, $contextid) = explode(',', $cat);
-        $catcontext = \context::instance_by_id($contextid);
-        $thiscontext = $this->get_most_specific_context();
-
-        // Category selection form.
-        $this->display_question_bank_header();
-        array_unshift($this->searchconditions, new tag_condition([$catcontext, $thiscontext], $tagids));
-        array_unshift($this->searchconditions, new hidden_condition(!$showhidden));
-        array_unshift($this->searchconditions, new category_condition($cat, $recurse, $contexts, $this->baseurl, $this->course));
-        $this->display_options_form($showquestiontext, '/mod/jazzquiz/edit.php');
-
-        // Continues with list of questions.
-        $this->display_question_list(
-            $this->baseurl,
-            $cat,
-            null,
-            $page,
-            $perpage,
-            $this->contexts->having_cap('moodle/question:add')
-        );
-        $this->display_add_selected_questions_button();
-        $PAGE->requires->js_call_amd('core_question/edit_tags', 'init', ['#questionscontainer']);
-    }
-
-    private function display_add_selected_questions_button() {
-        $straddtoquiz = get_string('add_to_quiz', 'jazzquiz');
-        echo 
-            '<br/>
-            <button class="btn btn-secondary jazzquiz-add-selected-questions">' . $straddtoquiz . '</button>
-            <i class="icon fa fa-question-circle text-info fa-fw " 
-                title="Add selected questions to the quiz" 
-                role="img" aria-label="Add selected questions to the quiz">
-            </i>';
-    }
-
-    /**
-     * Generate an "add to quiz" url so that when clicked the question will be added to the quiz
-     * @param int $questionid
-     * @return \moodle_url Moodle url to add the question
-     * @throws \moodle_exception
-     */
-    public function get_add_to_jazzquiz_url($questionid) {
-        $params = $this->baseurl->params();
-        $params['questionids'] = $questionid;
-        $params['action'] = 'addquestion';
-        $params['sesskey'] = sesskey();
-        return new \moodle_url('/mod/jazzquiz/edit.php', $params);
-    }
-
-    /**
-     * This has been taken from the base class to allow us to call our own version of
-     * create_new_question_button.
-     * @param \stdClass $category
-     * @param bool $add
-     * @throws \coding_exception
-     * @throws \moodle_exception
-     */
-    protected function create_new_question_form($category, $add): void {
-        echo '<div class="createnewquestion">';
-        if ($add) {
-            $caption = get_string('create_new_question', 'jazzquiz');
-            $this->create_new_question_button($category->id, $this->editquestionurl->params(), $caption);
-        } else {
-            print_string('nopermissionadd', 'question');
-        }
-        echo '</div>';
-    }
-
-    /**
-     * Print a button for creating a new question. This will open question/addquestion.php,
-     * which in turn goes to question/question.php before getting back to $params['returnurl']
-     * (by default the question bank screen).
-     *
-     * This has been taken from question/editlib.php and adapted to allow us to use the $allowedqtypes
-     * param on print_choose_qtype_to_add_form
-     *
-     * @param int $categoryid The id of the category that the new question should be added to.
-     * @param array $params Other parameters to add to the URL. You need either $params['cmid'] or
-     *      $params['courseid'], and you should probably set $params['returnurl']
-     * @param string $caption the text to display on the button.
-     * @param string $tooltip a tooltip to add to the button (optional).
-     * @param bool $disabled if true, the button will be disabled.
-     * @throws \moodle_exception
-     */
-    private function create_new_question_button($categoryid, $params, $caption, $tooltip = '', $disabled = false) {
-        global $OUTPUT;
-
-        $params['category'] = $categoryid;
-        $url = new \moodle_url('/question/addquestion.php', $params);
-
-        echo $OUTPUT->single_button($url, $caption, 'get', [
-            'disabled' => $disabled,
-            'title' => $tooltip
-        ]);
-
-        static $choiceformprinted = false;
-        if (!$choiceformprinted) {
-            echo '<div id="qtypechoicecontainer">';
-            echo print_choose_qtype_to_add_form([]);
-            echo "</div>\n";
-            $choiceformprinted = true;
-        }
-
-        // Add some top margin to the table (not viable via CSS).
-        echo '<br><br>';
-    }
-
-}
diff --git a/classes/bank/question_bank_add_to_jazzquiz_action_column.php b/classes/bank/question_bank_add_to_jazzquiz_action_column.php
deleted file mode 100755
index e6a501f..0000000
--- a/classes/bank/question_bank_add_to_jazzquiz_action_column.php
+++ /dev/null
@@ -1,68 +0,0 @@
-<?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/>.
-
-/**
- * Defines table column class for adding a question from the question bank to a JazzQuiz.
- * @package     mod_jazzquiz
- * @author      John Hoopes <moodle@madisoncreativeweb.com>
- * @copyright   2014 University of Wisconsin - Madison
- * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
-
-namespace mod_jazzquiz\bank;
-
-defined('MOODLE_INTERNAL') || die();
-
-/**
- * Custom action column for adding a question to the JazzQuiz from the question bank view
- *
- * @package     mod_jazzquiz
- * @author      John Hoopes <moodle@madisoncreativeweb.com>
- * @copyright   2014 University of Wisconsin - Madison
- * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
-class question_bank_add_to_jazzquiz_action_column extends \core_question\local\bank\action_column_base {
-
-    /**
-     * Get the name of the column.
-     * @return string
-     */
-    public function get_name() {
-        return 'addtojazzquizaction';
-    }
-
-    /**
-     * Show the button to add the question.
-     * @param object $question
-     * @param string $rowclasses
-     */
-    protected function display_content($question, $rowclasses) {
-        if (!question_has_capability_on($question, 'use')) {
-            return;
-        }
-        $text = get_string('add_to_quiz', 'jazzquiz');
-        $this->print_icon('t/add', $text, $this->qbank->get_add_to_jazzquiz_url($question->id));
-    }
-
-    /**
-     * Get the required fields.
-     * @return string[]
-     */
-    public function get_required_fields(): array {
-        return ['q.id'];
-    }
-
-}
diff --git a/classes/exporter.php b/classes/exporter.php
index b7a379c..84c8bb4 100755
--- a/classes/exporter.php
+++ b/classes/exporter.php
@@ -16,8 +16,6 @@
 
 namespace mod_jazzquiz;
 
-defined('MOODLE_INTERNAL') || die;
-
 /**
  * @package   mod_jazzquiz
  * @author    Sebastian S. Gundersen <sebastian@sgundersen.com>
@@ -28,10 +26,11 @@ class exporter {
 
     /**
      * Escape the characters used for structuring the CSV contents.
+     *
      * @param string $text
      * @return string
      */
-    public static function escape_csv(string $text) : string {
+    public static function escape_csv(string $text): string {
         $text = str_replace("\r", '', $text);
         $text = str_replace("\n", '', $text);
         $text = str_replace("\t", '    ', $text);
@@ -42,18 +41,19 @@ public static function escape_csv(string $text) : string {
      * Sets header to download csv file of given filename.
      * @param string $name filename without extension
      */
-    private function csv_file(string $name) {
+    private function csv_file(string $name): void {
         header("Content-Disposition: attachment; filename=$name.csv");
         echo "sep=\t\r\n";
     }
 
     /**
      * Export session data to array.
+     *
      * @param jazzquiz_session $session
      * @param jazzquiz_attempt[] $quizattempts
      * @return array
      */
-    public function export_session(jazzquiz_session $session, array $quizattempts) : array {
+    public function export_session(jazzquiz_session $session, array $quizattempts): array {
         $quizattempt = reset($quizattempts);
         $qubaslots = $quizattempt->quba->get_slots();
         $slots = [];
@@ -64,12 +64,12 @@ public function export_session(jazzquiz_session $session, array $quizattempts) :
             $slots[$slot] = [
                 'name' => $question->name,
                 'qtype' => $qtype,
-                'responses' => []
+                'responses' => [],
             ];
         }
         $users = [];
         foreach ($quizattempts as $quizattempt) {
-            if ($quizattempt->data->status == jazzquiz_attempt::PREVIEW) {
+            if ($quizattempt->status == jazzquiz_attempt::PREVIEW) {
                 continue;
             }
             $answers = [];
@@ -77,8 +77,8 @@ public function export_session(jazzquiz_session $session, array $quizattempts) :
                 $answers[$slot] = $quizattempt->get_response_data($slot);
             }
             $users[] = [
-                'name' => $session->user_name_for_answer($quizattempt->data->userid),
-                'answers' => $answers
+                'name' => $session->user_name_for_answer($quizattempt->userid),
+                'answers' => $answers,
             ];
         }
         $name = 'session_' . $session->data->id . '_' . $session->data->name;
@@ -87,10 +87,11 @@ public function export_session(jazzquiz_session $session, array $quizattempts) :
 
     /**
      * Export and print session data as CSV.
+     *
      * @param jazzquiz_session $session
      * @param jazzquiz_attempt[] $attempts
      */
-    public function export_session_csv(jazzquiz_session $session, array $attempts) {
+    public function export_session_csv(jazzquiz_session $session, array $attempts): void {
         list($name, $slots, $users) = $this->export_session($session, $attempts);
         $this->csv_file($name);
         // Header row.
@@ -115,12 +116,13 @@ public function export_session_csv(jazzquiz_session $session, array $attempts) {
 
     /**
      * Export session question data to array.
+     *
      * @param jazzquiz_session $session
      * @param jazzquiz_attempt $attempt
      * @param int $slot
      * @return array
      */
-    public function export_session_question(jazzquiz_session $session, jazzquiz_attempt $attempt, int $slot) : array {
+    public function export_session_question(jazzquiz_session $session, jazzquiz_attempt $attempt, int $slot): array {
         $qattempt = $attempt->quba->get_question_attempt($slot);
         $question = $qattempt->get_question();
         $session->load_attempts();
@@ -132,11 +134,12 @@ public function export_session_question(jazzquiz_session $session, jazzquiz_atte
 
     /**
      * Export and print session question data as CSV.
+     *
      * @param jazzquiz_session $session
      * @param jazzquiz_attempt $attempt
      * @param int $slot
      */
-    public function export_session_question_csv(jazzquiz_session $session, jazzquiz_attempt $attempt, int $slot) {
+    public function export_session_question_csv(jazzquiz_session $session, jazzquiz_attempt $attempt, int $slot): void {
         list($name, $text, $responses) = $this->export_session_question($session, $attempt, $slot);
         $this->csv_file($name);
         echo "$text\r\n";
@@ -147,9 +150,10 @@ public function export_session_question_csv(jazzquiz_session $session, jazzquiz_
 
     /**
      * Export and print session attendance data as CSV.
+     *
      * @param jazzquiz_session $session
      */
-    public function export_attendance_csv(jazzquiz_session $session) {
+    public function export_attendance_csv(jazzquiz_session $session): void {
         $name = $session->data->id . '_' . $session->data->name;
         $attendances = $session->get_attendances();
         $this->csv_file("session_{$name}_attendance");
diff --git a/classes/forms/view/start_session.php b/classes/forms/view/start_session.php
index a7f6bd2..97b3b92 100755
--- a/classes/forms/view/start_session.php
+++ b/classes/forms/view/start_session.php
@@ -25,6 +25,8 @@
 
 namespace mod_jazzquiz\forms\view;
 
+use moodleform;
+
 defined('MOODLE_INTERNAL') || die();
 
 require_once($CFG->libdir . '/formslib.php');
@@ -39,23 +41,23 @@
  * @copyright 2019 NTNU
  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-class start_session extends \moodleform {
+class start_session extends moodleform {
 
     /**
      * Overriding parent function to account for namespace in the class name
-     * so that client validation works
+     * so that client validation works.
      *
-     * @return mixed|string
+     * @return string
      */
-    protected function get_form_identifier() {
+    protected function get_form_identifier(): string {
         $class = get_class($this);
         return preg_replace('/[^a-z0-9_]/i', '_', $class);
     }
 
     /**
-     * Definition of the session start form
+     * Definition of the session start form.
      */
-    public function definition() {
+    public function definition(): void {
         $mform = $this->_form;
         $jazzquiz = $this->_customdata['jazzquiz'];
         $mform->addElement('text', 'session_name', get_string('session_name', 'jazzquiz'));
@@ -64,7 +66,7 @@ public function definition() {
         $anonymity = [
             $mform->createElement('radio', 'anonymity', '', get_string('anonymous_answers', 'jazzquiz'), 1, []),
             $mform->createElement('radio', 'anonymity', '', get_string('fully_anonymous', 'jazzquiz'), 2, []),
-            $mform->createElement('radio', 'anonymity', '', get_string('nonanonymous_session', 'jazzquiz'), 3, [])
+            $mform->createElement('radio', 'anonymity', '', get_string('nonanonymous_session', 'jazzquiz'), 3, []),
         ];
         $mform->addGroup($anonymity, 'anonymity', '', ['<br>', ''], false);
         $mform->setDefault('anonymity', $jazzquiz->data->cfganonymity);
@@ -74,14 +76,13 @@ public function definition() {
     }
 
     /**
-     * Peform validation on the form
+     * Peform validation on the form.
      *
      * @param array $data
      * @param array $files
-     *
-     * @return string[] $errors array of errors
+     * @return string[] errors
      */
-    public function validations($data, $files) {
+    public function validations($data, $files): array {
         $errors = [];
         if (empty($data['session_name'])) {
             $errors['session_name'] = get_string('session_name_required', 'jazzquiz');
diff --git a/classes/improviser.php b/classes/improviser.php
index 98550c6..62fbc1a 100755
--- a/classes/improviser.php
+++ b/classes/improviser.php
@@ -16,7 +16,9 @@
 
 namespace mod_jazzquiz;
 
-defined('MOODLE_INTERNAL') || die();
+use context_module;
+use core_question\local\bank\question_edit_contexts;
+use stdClass;
 
 /**
  * @package     mod_jazzquiz
@@ -27,7 +29,7 @@
 class improviser {
 
     /** @var jazzquiz $jazzquiz */
-    private $jazzquiz;
+    private jazzquiz $jazzquiz;
 
     /**
      * @param jazzquiz $jazzquiz
@@ -38,10 +40,11 @@ public function __construct(jazzquiz $jazzquiz) {
 
     /**
      * Check whether a question type exists or not.
+     *
      * @param string $name Name of the question type
      * @return bool
      */
-    private function question_type_exists(string $name) : bool {
+    private function question_type_exists(string $name): bool {
         $qtypes = \core_plugin_manager::instance()->get_plugins_of_type('qtype');
         foreach ($qtypes as $qtype) {
             if ($qtype->name === $name) {
@@ -53,17 +56,15 @@ private function question_type_exists(string $name) : bool {
 
     /**
      * Get all the improvised question records in our activity's question category.
-     * @return \stdClass[]|false
+     *
+     * @return stdClass[]
      */
-    public function get_all_improvised_question_definitions() {
+    public function get_all_improvised_question_definitions(): array {
         global $DB;
         $questions = [];
-        $context = \context_module::instance($this->jazzquiz->cm->id);
-        $parts = explode('/', $context->path);
-        debugging( "get_all_improvised: ".$parts );
-        foreach ($parts as $part) {
+        $context = context_module::instance($this->jazzquiz->cm->id);
+        foreach (explode('/', $context->path) as $part) {
             // Selecting name first, to prevent duplicate improvise questions.
-            debugging( "get_all_improvised: ".$part );
             $sql = "SELECT q.name,
                            q.id
                       FROM {question} q
@@ -78,21 +79,25 @@ public function get_all_improvised_question_definitions() {
                        AND ctx.path LIKE :path
                      WHERE q.name LIKE :prefix
                   ORDER BY q.name";
-            $questions += $DB->get_records_sql($sql, ['prefix' => '{IMPROV}%', 'path' => '%/' . $part]);
+            $questions[] = $DB->get_records_sql($sql, [
+                'prefix' => '{IMPROV}%',
+                'path' => "%/$part",
+            ]);
         }
-        return $questions ? $questions : false;
+        return $questions;
     }
 
     /**
      * Get the specified question name is an improvisational question.
+     *
      * @param string $name The name of the improvised question without the prefix.
-     * @return \stdClass|false
+     * @return ?stdClass
      */
-    private function get_improvised_question_definition(string $name) {
+    private function get_improvised_question_definition(string $name): ?stdClass {
         global $DB;
         $category = $this->get_default_question_category();
         if (!$category) {
-            return false;
+            return null;
         }
         $sql = "SELECT qbe.id
                   FROM {question_bank_entries} qbe
@@ -101,32 +106,29 @@ private function get_improvised_question_definition(string $name) {
                  WHERE qbe.questioncategoryid = :catid
                    AND q.name LIKE :name";
         $questions = $DB->get_records_sql($sql, ['catid' => $category->id, 'name' => '{IMPROV}' . $name]);
-        if (!$questions) {
-            return false;
-        }
-        return reset($questions);
+        return empty($questions) ? null : reset($questions);
     }
 
     /**
      * Deletes the improvised question definition with matching name if it exists.
+     *
      * @param string $name of question
      */
-    private function delete_improvised_question(string $name) {
+    private function delete_improvised_question(string $name): void {
         $question = $this->get_improvised_question_definition($name);
-        if ($question !== false) {
+        if ($question !== null) {
             question_delete_question($question->id);
         }
     }
 
     /**
      * Returns the default question category for the activity.
-     * @return object
      */
-    private function get_default_question_category() {
-        $context = \context_module::instance($this->jazzquiz->cm->id);
+    private function get_default_question_category(): stdClass|bool|null {
+        $context = context_module::instance($this->jazzquiz->cm->id);
         $category = question_get_default_category($context->id);
         if (!$category) {
-            $contexts = new \core_question\local\bank\question_edit_contexts($context);
+            $contexts = new question_edit_contexts($context);
             $category = question_make_default_categories($contexts->all());
         }
         return $category;
@@ -134,16 +136,15 @@ private function get_default_question_category() {
 
     /**
      * Create a question bank entry for the database.
-     * @return \stdClass | null
+     *
+     * @return ?stdClass
      */
-    private function make_generic_question_bank_entry() {
+    private function make_generic_question_bank_entry(): ?stdClass {
         $category = $this->get_default_question_category();
         if (!$category) {
             return null;
         }
-
-        /* debugging( "Making generic question bank entry." ) ; */
-        $question = new \stdClass();
+        $question = new stdClass();
         $question->questioncategoryid = $category->id;
         $question->ownerid = null;
         $question->idnumber = null;
@@ -152,21 +153,20 @@ private function make_generic_question_bank_entry() {
 
     /**
      * Create a question database object.
+     *
      * @param string $qtype What question type to create
      * @param string $name The name of the question to create
-     * @return \stdClass | null
+     * @return ?stdClass
      */
-    private function make_generic_question_definition(string $qtype, string $name) {
+    private function make_generic_question_definition(string $qtype, string $name): ?stdClass {
         if (!$this->question_type_exists($qtype)) {
-            /* debugging( "make_generic_question_definition: question type does not exist" ) ; */
             return null;
         }
-        $existing = $this->get_improvised_question_definition($name);
-        if ($existing !== false) {
-            /* debugging( "make_generic_question_definition: existing: ".$name ) ; */
+        $existingdefinition = $this->get_improvised_question_definition($name);
+        if ($existingdefinition !== null) {
             return null;
         }
-        $question = new \stdClass();
+        $question = new stdClass();
         $question->parent = 0;
         $question->name = '{IMPROV}' . $name;
         $question->questiontext = '&nbsp;';
@@ -187,11 +187,12 @@ private function make_generic_question_definition(string $qtype, string $name) {
 
     /**
      * Create a multichoice options database object.
+     *
      * @param int $questionid The ID of the question to make options for
-     * @return \stdClass
+     * @return stdClass
      */
-    private function make_multichoice_options($questionid) {
-        $options = new \stdClass();
+    private function make_multichoice_options(int $questionid): stdClass {
+        $options = new stdClass();
         $options->questionid = $questionid;
         $options->layout = 0;
         $options->single = 1;
@@ -209,11 +210,12 @@ private function make_multichoice_options($questionid) {
 
     /**
      * Make a short answer question options database object.
+     *
      * @param int $questionid The ID of the question to make options for
-     * @return \stdClass
+     * @return stdClass
      */
-    private function make_shortanswer_options($questionid) {
-        $options = new \stdClass();
+    private function make_shortanswer_options(int $questionid): stdClass {
+        $options = new stdClass();
         $options->questionid = $questionid;
         $options->usecase = 0;
         return $options;
@@ -221,13 +223,14 @@ private function make_shortanswer_options($questionid) {
 
     /**
      * Make an answer for a question.
+     *
      * @param int $questionid The ID of the question to make the answer for
      * @param string $format Which format the answer has
      * @param string $answertext The answer text
-     * @return \stdClass
+     * @return stdClass
      */
-    private function make_generic_question_answer($questionid, string $format, string $answertext) {
-        $answer = new \stdClass();
+    private function make_generic_question_answer(int $questionid, string $format, string $answertext): stdClass {
+        $answer = new stdClass();
         $answer->question = $questionid;
         $answer->answer = $answertext;
         $answer->answerformat = $format;
@@ -239,24 +242,23 @@ private function make_generic_question_answer($questionid, string $format, strin
 
     /**
      * Insert a multichoice question to the database.
+     *
      * @param string $name The name of the question
      * @param string[] $answers Answers to the question
      */
-    private function insert_multichoice_question_definition(string $name, array $answers) {
+    private function insert_multichoice_question_definition(string $name, array $answers): void {
         global $DB;
-        /* debugging("insert_multichoice_question_definition: ".$name ) ; */
         $question = $this->make_generic_question_definition('multichoice', $name);
         if (!$question) {
             return;
         }
-        /* debugging("insert_multichoice_question_definition 2") ; */
         $qbankentry = $this->make_generic_question_bank_entry();
         if (!$qbankentry) {
             return;
         }
         $question->id = $DB->insert_record('question', $question);
         $qbankentry->id = $DB->insert_record('question_bank_entries', $qbankentry);
-        $this->insert_question_version( $qbankentry->id, $question->id );
+        $this->insert_question_version($qbankentry->id, $question->id);
         // Add options.
         $options = $this->make_multichoice_options($question->id);
         $DB->insert_record('qtype_multichoice_options', $options);
@@ -265,23 +267,23 @@ private function insert_multichoice_question_definition(string $name, array $ans
             $qanswer = $this->make_generic_question_answer($question->id, 1, $answer);
             $DB->insert_record('question_answers', $qanswer);
         }
-        /* debugging( "Question ID ".$question->id ); */
     }
 
-    /* Create a question version database object, linking the given question
-     * and question bank entry.
+    /**
+     * Create a question version database object, linking the given question and question bank entry.
+     *
      * @param int $qbankid The ID of the question banke entry
      * @param int $qid The ID of the question
-     * @return \stdClass
+     * @return stdClass
      */
-    private function insert_question_version(int $qbankid, int $qid) {
+    private function insert_question_version(int $qbankid, int $qid): stdClass {
         global $DB;
-        $qv = new \stdClass();
-        $qv->questionbankentryid = $qbankid;
-        $qv->version = 1;
-        $qv->questionid = $qid;
-        $qv->id = $DB->insert_record('question_versions', $qv);
-        return $qv;
+        $questionversion = new stdClass();
+        $questionversion->questionbankentryid = $qbankid;
+        $questionversion->version = 1;
+        $questionversion->questionid = $qid;
+        $questionversion->id = $DB->insert_record('question_versions', $questionversion);
+        return $questionversion;
     }
 
     /**
@@ -290,7 +292,6 @@ private function insert_question_version(int $qbankid, int $qid) {
      */
     private function insert_shortanswer_question_definition(string $name) {
         global $DB;
-        /* debugging("insert_shortanswer_question_definition: ".$name ) ; */
         $question = $this->make_generic_question_definition('shortanswer', $name);
         if (!$question) {
             return;
@@ -301,7 +302,7 @@ private function insert_shortanswer_question_definition(string $name) {
         }
         $question->id = $DB->insert_record('question', $question);
         $qbankentry->id = $DB->insert_record('question_bank_entries', $qbankentry);
-        $this->insert_question_version( $qbankentry->id, $question->id );
+        $this->insert_question_version($qbankentry->id, $question->id);
 
         // Add options.
         $options = $this->make_shortanswer_options($question->id);
@@ -311,9 +312,8 @@ private function insert_shortanswer_question_definition(string $name) {
         $DB->insert_record('question_answers', $answer);
     }
 
-    private function insert_shortmath_question_definition(string $name) {
+    private function insert_shortmath_question_definition(string $name): void {
         global $DB;
-        /* debugging("insert_shortmath_question_definition: ".$name ) ; */
         $question = $this->make_generic_question_definition('shortmath', $name);
         if (!$question) {
             return;
@@ -337,7 +337,7 @@ private function insert_shortmath_question_definition(string $name) {
      * Insert all the improvised question definitions to the question bank.
      * Every question will have a prefix of {IMPROV}
      */
-    public function insert_default_improvised_question_definitions() {
+    public function insert_default_improvised_question_definitions(): void {
         $multichoice = get_string('multichoice_options', 'jazzquiz');
         $yes = get_string('yes');
         $no = get_string('no');
@@ -346,7 +346,7 @@ public function insert_default_improvised_question_definitions() {
         $this->insert_multichoice_question_definition("5 $multichoice", ['A', 'B', 'C', 'D', 'E']);
         $this->insert_shortanswer_question_definition(get_string('short_answer', 'jazzquiz'));
         // TODO: Remove the check in the future, 2020+. Avoid messing with as many existing instances as possible.
-        if (!$this->get_improvised_question_definition('True / False')) {
+        if ($this->get_improvised_question_definition('True / False') === null) {
             $this->insert_multichoice_question_definition("$yes / $no", [$yes, $no]);
         }
         $this->insert_shortmath_question_definition(get_string('short_math_answer', 'jazzquiz'));
diff --git a/classes/jazzquiz.php b/classes/jazzquiz.php
index f9d9eda..28995b5 100755
--- a/classes/jazzquiz.php
+++ b/classes/jazzquiz.php
@@ -16,7 +16,12 @@
 
 namespace mod_jazzquiz;
 
-defined('MOODLE_INTERNAL') || die();
+use context_module;
+use core\context\module;
+use moodle_url;
+use question_display_options;
+use renderer_base;
+use stdClass;
 
 /**
  * @package   mod_jazzquiz
@@ -26,52 +31,49 @@
  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class jazzquiz {
+
     /**
      * @var array $review fields Static review fields to add as options
      */
-    public static $reviewfields = [
+    public static array $reviewfields = [
         'attempt' => ['theattempt', 'jazzquiz'],
         'correctness' => ['whethercorrect', 'question'],
         'marks' => ['marks', 'jazzquiz'],
         'specificfeedback' => ['specificfeedback', 'question'],
         'generalfeedback' => ['generalfeedback', 'question'],
         'rightanswer' => ['rightanswer', 'question'],
-        'manualcomment' => ['manualcomment', 'jazzquiz']
+        'manualcomment' => ['manualcomment', 'jazzquiz'],
     ];
 
-    /** @var \stdClass $cm course module */
-    public $cm;
-
-    /** @var \stdClass $course */
-    public $course;
+    /** @var stdClass $cm course module */
+    public stdClass $cm;
 
-    /** @var \context_module $context */
-    public $context;
+    /** @var stdClass $course */
+    public stdClass $course;
 
-    /** @var \plugin_renderer_base|output\renderer $renderer */
-    public $renderer;
+    /** @var module $context */
+    public module $context;
 
-    /** @var \stdClass $data The jazzquiz database table row */
-    public $data;
+    /** @var renderer_base $renderer */
+    public renderer_base $renderer;
 
-    /** @var bool $isinstructor */
-    protected $isinstructor;
+    /** @var stdClass $data The jazzquiz database table row */
+    public stdClass $data;
 
-    /** @var jazzquiz_question[] */
-    public $questions;
+    /** @var jazzquiz_question[] $questions */
+    public array $questions;
 
     /**
      * @param int $cmid The course module ID
-     * @param string $renderersubtype Renderer sub-type to load if requested
      */
-    public function __construct($cmid) {
+    public function __construct(int $cmid) {
         global $PAGE, $DB;
         $this->cm = get_coursemodule_from_id('jazzquiz', $cmid, 0, false, MUST_EXIST);
 
         // TODO: Login requirement must be moved over to caller.
         require_login($this->cm->course, false, $this->cm);
 
-        $this->context = \context_module::instance($cmid);
+        $this->context = context_module::instance($cmid);
         $PAGE->set_context($this->context);
         $this->renderer = $PAGE->get_renderer('mod_jazzquiz');
 
@@ -81,66 +83,68 @@ public function __construct($cmid) {
     }
 
     /**
-     * Sets up the display options for the question
+     * Sets up the display options for the question.
+     *
      * @param bool $review
-     * @param string|\stdClass $reviewoptions
-     * @return \question_display_options
+     * @param string|stdClass $reviewoptions
+     * @return question_display_options
      */
-    public function get_display_options(bool $review, $reviewoptions) {
-        $options = new \question_display_options();
-        $options->flags = \question_display_options::HIDDEN;
+    public function get_display_options(bool $review, string|stdClass $reviewoptions): question_display_options {
+        $options = new question_display_options();
+        $options->flags = question_display_options::HIDDEN;
         $options->context = $this->context;
-        $options->marks = \question_display_options::HIDDEN;
+        $options->marks = question_display_options::HIDDEN;
         if ($review) {
             // Default display options for review.
             $options->readonly = true;
             $options->hide_all_feedback();
             // Special case for "edit" review options value.
             if ($reviewoptions === 'edit') {
-                $options->correctness = \question_display_options::VISIBLE;
-                $options->marks = \question_display_options::MARK_AND_MAX;
-                $options->feedback = \question_display_options::VISIBLE;
-                $options->numpartscorrect = \question_display_options::VISIBLE;
-                $options->manualcomment = \question_display_options::EDITABLE;
-                $options->generalfeedback = \question_display_options::VISIBLE;
-                $options->rightanswer = \question_display_options::VISIBLE;
-                $options->history = \question_display_options::VISIBLE;
-            } else if ($reviewoptions instanceof \stdClass) {
+                $options->correctness = question_display_options::VISIBLE;
+                $options->marks = question_display_options::MARK_AND_MAX;
+                $options->feedback = question_display_options::VISIBLE;
+                $options->numpartscorrect = question_display_options::VISIBLE;
+                $options->manualcomment = question_display_options::EDITABLE;
+                $options->generalfeedback = question_display_options::VISIBLE;
+                $options->rightanswer = question_display_options::VISIBLE;
+                $options->history = question_display_options::VISIBLE;
+            } else if ($reviewoptions instanceof stdClass) {
                 foreach (self::$reviewfields as $field => $unused) {
                     if ($reviewoptions->$field == 1) {
                         if ($field == 'specificfeedback') {
                             $field = 'feedback';
                         }
                         if ($field == 'marks') {
-                            $options->$field = \question_display_options::MARK_AND_MAX;
+                            $options->$field = question_display_options::MARK_AND_MAX;
                         } else {
-                            $options->$field = \question_display_options::VISIBLE;
+                            $options->$field = question_display_options::VISIBLE;
                         }
                     }
                 }
             }
         } else {
             // Default options for running quiz.
-            $options->rightanswer = \question_display_options::HIDDEN;
-            $options->numpartscorrect = \question_display_options::HIDDEN;
-            $options->manualcomment = \question_display_options::HIDDEN;
-            $options->manualcommentlink = \question_display_options::HIDDEN;
+            $options->rightanswer = question_display_options::HIDDEN;
+            $options->numpartscorrect = question_display_options::HIDDEN;
+            $options->manualcomment = question_display_options::HIDDEN;
+            $options->manualcommentlink = question_display_options::HIDDEN;
         }
         return $options;
     }
 
     /**
-     * Get the open session. If none exist, false is returned.
-     * @return jazzquiz_session|false
+     * Get the open session. Returns null if no session is open.
+     *
+     * @return ?jazzquiz_session
      */
-    public function load_open_session() {
+    public function load_open_session(): ?jazzquiz_session {
         global $DB;
         $sessions = $DB->get_records('jazzquiz_sessions', [
             'jazzquizid' => $this->data->id,
-            'sessionopen' => 1
+            'sessionopen' => 1,
         ], 'id');
-        if (count($sessions) === 0) {
-            return false;
+        if (empty($sessions)) {
+            return null;
         }
         $session = reset($sessions);
         return new jazzquiz_session($this, $session->id);
@@ -148,30 +152,31 @@ public function load_open_session() {
 
     /**
      * Check if a session is open for this quiz.
+     *
      * @return bool true if open
      */
-    public function is_session_open() {
+    public function is_session_open(): bool {
         global $DB;
-        $sessions = $DB->get_records('jazzquiz_sessions', [
+        return $DB->record_exists('jazzquiz_sessions', [
             'jazzquizid' => $this->data->id,
-            'sessionopen' => 1
+            'sessionopen' => 1,
         ]);
-        return count($sessions);
     }
 
     /**
      * Create a new session for this quiz.
+     *
      * @param string $name
      * @param int $anonymity
-     * @param int $allowguests
-     * @return int|false Session ID returned if successful, else false.
+     * @param bool $allowguests
      */
-    public function create_session(string $name, int $anonymity, int $allowguests) {
+    public function create_session(string $name, int $anonymity, bool $allowguests): void {
         global $DB;
         $this->data->cfganonymity = $anonymity;
-        $this->data->cfgallowguests = $allowguests;
-        $this->save();
-        $session = new \stdClass();
+        $this->data->cfgallowguests = $allowguests ? 1 : 0;
+        $DB->update_record('jazzquiz', $this->data);
+
+        $session = new stdClass();
         $session->name = $name;
         $session->jazzquizid = $this->data->id;
         $session->sessionopen = 1;
@@ -179,22 +184,9 @@ public function create_session(string $name, int $anonymity, int $allowguests) {
         $session->slot = 0;
         $session->anonymity = $anonymity;
         $session->showfeedback = false;
-        $session->allowguests = $allowguests;
+        $session->allowguests = $allowguests ? 1 : 0;
         $session->created = time();
-        try {
-            return $DB->insert_record('jazzquiz_sessions', $session);
-        } catch (\Exception $e) {
-            return false;
-        }
-    }
-
-    /**
-     * Saves the JazzQuiz instance to the database
-     * @return bool
-     */
-    public function save() {
-        global $DB;
-        return $DB->update_record('jazzquiz', $this->data);
+        $DB->insert_record('jazzquiz_sessions', $session);
     }
 
     /**
@@ -205,9 +197,9 @@ public function save() {
      *
      * @param int $questionid The question bank's question id
      */
-    public function add_question($questionid) {
+    public function add_question(int $questionid): void {
         global $DB;
-        $question = new \stdClass();
+        $question = new stdClass();
         $question->jazzquizid = $this->data->id;
         $question->questionid = $questionid;
         $question->questiontime = $this->data->defaultquestiontime;
@@ -223,7 +215,7 @@ public function add_question($questionid) {
      *
      * @param int[] $order
      */
-    public function set_question_order(array $order) {
+    public function set_question_order(array $order): void {
         global $DB;
         $order = array_unique($order);
         $questions = $DB->get_records('jazzquiz_questions', ['jazzquizid' => $this->data->id], 'slot');
@@ -242,7 +234,7 @@ public function set_question_order(array $order) {
     /**
      * @return int[] of jazzquiz_question id
      */
-    public function get_question_order() : array {
+    public function get_question_order(): array {
         $order = [];
         foreach ($this->questions as $question) {
             $order[] = $question->data->id;
@@ -254,9 +246,9 @@ public function get_question_order() : array {
      * Edit a JazzQuiz question
      * @param int $questionid the JazzQuiz question id
      */
-    public function edit_question($questionid) {
+    public function edit_question(int $questionid): void {
         global $DB;
-        $url = new \moodle_url('/mod/jazzquiz/edit.php', ['id' => $this->cm->id]);
+        $url = new moodle_url('/mod/jazzquiz/edit.php', ['id' => $this->cm->id]);
         $actionurl = clone($url);
         $actionurl->param('action', 'editquestion');
         $actionurl->param('questionid', $questionid);
@@ -267,7 +259,7 @@ public function edit_question($questionid) {
         $mform = new forms\edit\add_question_form($actionurl, [
             'jazzquiz' => $this,
             'questionname' => $question->name,
-            'edit' => true
+            'edit' => true,
         ]);
 
         // Form handling.
@@ -276,7 +268,7 @@ public function edit_question($questionid) {
             $url->remove_params('action');
             redirect($url, null, 0);
         } else if ($data = $mform->get_data()) {
-            $question = new \stdClass();
+            $question = new stdClass();
             $question->id = $jazzquizquestion->id;
             $question->jazzquizid = $this->data->id;
             $question->questionid = $jazzquizquestion->questionid;
@@ -293,7 +285,7 @@ public function edit_question($questionid) {
             // Display the form.
             $mform->set_data([
                 'questiontime' => $jazzquizquestion->questiontime,
-                'notime' => ($jazzquizquestion->questiontime < 1)
+                'notime' => $jazzquizquestion->questiontime < 1,
             ]);
             $this->renderer->header($this, 'edit');
             echo '<div class="generalbox boxaligncenter jazzquiz-box">';
@@ -306,7 +298,7 @@ public function edit_question($questionid) {
     /**
      * Loads the quiz questions from the database, ordered by slot.
      */
-    public function refresh_questions() {
+    public function refresh_questions(): void {
         global $DB;
         $this->questions = [];
         $questions = $DB->get_records('jazzquiz_questions', ['jazzquizid' => $this->data->id], 'slot');
@@ -322,34 +314,33 @@ public function refresh_questions() {
 
     /**
      * @param int $jazzquizquestionid
-     * @return jazzquiz_question|bool
+     * @return ?jazzquiz_question
      */
-    public function get_question_by_id($jazzquizquestionid) {
+    public function get_question_by_id(int $jazzquizquestionid): ?jazzquiz_question {
         foreach ($this->questions as $question) {
             if ($question->data->id == $jazzquizquestionid) {
                 return $question;
             }
         }
-        return false;
+        return null;
     }
 
     /**
-     * Quick function for whether or not the current user is the instructor/can control the quiz
+     * Check if the current user is an instructor in this quiz.
+     *
      * @return bool
      */
-    public function is_instructor() : bool {
-        if (is_null($this->isinstructor)) {
-            $this->isinstructor = has_capability('mod/jazzquiz:control', $this->context);
-        }
-        return $this->isinstructor;
+    public function is_instructor(): bool {
+        return has_capability('mod/jazzquiz:control', $this->context);
     }
 
     /**
-     * Get all sessions for this jazzquiz
+     * Get all sessions for this jazzquiz.
+     *
      * @param array $conditions
-     * @return \stdClass[]
+     * @return stdClass[]
      */
-    public function get_sessions(array $conditions = []) : array {
+    public function get_sessions(array $conditions = []): array {
         global $DB;
         $conditions = array_merge(['jazzquizid' => $this->data->id], $conditions);
         return $DB->get_records('jazzquiz_sessions', $conditions);
diff --git a/classes/jazzquiz_attempt.php b/classes/jazzquiz_attempt.php
index f0ad7cb..a51aabc 100755
--- a/classes/jazzquiz_attempt.php
+++ b/classes/jazzquiz_attempt.php
@@ -16,7 +16,12 @@
 
 namespace mod_jazzquiz;
 
-defined('MOODLE_INTERNAL') || die();
+use context_module;
+use core\context\module;
+use question_bank;
+use question_engine;
+use question_usage_by_activity;
+use stdClass;
 
 /**
  * An attempt for the quiz. Maps to individual question attempts.
@@ -35,55 +40,56 @@ class jazzquiz_attempt {
     const PREVIEW = 20;
     const FINISHED = 30;
 
-    /** @var \stdClass */
-    public $data;
+    public int $id;
+    public int $sessionid;
+    public ?int $userid;
+    public int $questionengid;
+    public ?string $guestsession;
+    public int $status;
+    public ?int $responded;
+    public int $timestart;
+    public ?int $timefinish;
+    public int $timemodified;
 
-    /** @var \question_usage_by_activity $quba the question usage by activity for this attempt */
-    public $quba;
+    /** @var question_usage_by_activity the question usage by activity for this attempt */
+    public question_usage_by_activity $quba;
 
-    /**
-     * Construct the class. If data is passed in we set it, otherwise initialize empty class
-     * @param \context_module $context
-     * @param \stdClass $data
-     */
-    public function __construct(\context_module $context, \stdClass $data = null) {
-        if (empty($data)) {
-            // Create new attempt.
-            $this->data = new \stdClass();
-            // Create a new quba since we're creating a new attempt.
-            $this->quba = \question_engine::make_questions_usage_by_activity('mod_jazzquiz', $context);
-            $this->quba->set_preferred_behaviour('immediatefeedback');
-        } else {
-            // Load it up in this class instance.
-            $this->data = $data;
-            $this->quba = \question_engine::load_questions_usage_by_activity($this->data->questionengid);
-        }
+    private function __construct(stdClass $record) {
+        $this->id = $record->id;
+        $this->sessionid = $record->sessionid;
+        $this->userid = $record->userid;
+        $this->questionengid = $record->questionengid;
+        $this->guestsession = $record->guestsession;
+        $this->status = $record->status;
+        $this->responded = $record->responded;
+        $this->timestart = $record->timestart;
+        $this->timefinish = $record->timefinish;
+        $this->timemodified = $record->timemodified;
+        $this->quba = question_engine::load_questions_usage_by_activity($this->questionengid);
     }
 
-    public function belongs_to_current_user() {
+    public function belongs_to_current_user(): bool {
         global $USER;
-        return $this->data->userid == $USER->id || $this->data->guestsession == $USER->sesskey;
+        return $this->userid == $USER->id || $this->guestsession === $USER->sesskey;
     }
 
     /**
      * Check if this attempt is currently in progress.
+     *
      * @return bool
      */
-    public function is_active() {
-        switch ($this->data->status) {
-            case self::INPROGRESS:
-            case self::PREVIEW:
-                return true;
-            default:
-                return false;
-        }
+    public function is_active(): bool {
+        return match ($this->status) {
+            self::INPROGRESS, self::PREVIEW => true,
+            default => false,
+        };
     }
 
     /**
      * @param jazzquiz_session $session
      * @return bool false if invalid question id
      */
-    public function create_missing_attempts(jazzquiz_session $session) {
+    public function create_missing_attempts(jazzquiz_session $session): bool {
         foreach ($session->questions as $slot => $question) {
             if ($this->quba->next_slot_number() > $slot) {
                 continue;
@@ -93,10 +99,10 @@ public function create_missing_attempts(jazzquiz_session $session) {
             if (!$questiondefinition) {
                 return false;
             }
-            $question = \question_bank::make_question($questiondefinition);
+            $question = question_bank::make_question($questiondefinition);
             $slot = $this->quba->add_question($question);
             $this->quba->start_question($slot);
-            $this->data->responded = 0;
+            $this->responded = 0;
         }
         return true;
     }
@@ -104,11 +110,10 @@ public function create_missing_attempts(jazzquiz_session $session) {
     /**
      * Anonymize all the question attempt steps for this quiz attempt.
      * It will be impossible to identify which user answered all questions linked to this question usage.
-     * @throws \dml_exception
      */
-    public function anonymize_answers() {
+    public function anonymize_answers(): void {
         global $DB;
-        $attempts = $DB->get_records('question_attempts', ['questionusageid' => $this->data->questionengid]);
+        $attempts = $DB->get_records('question_attempts', ['questionusageid' => $this->questionengid]);
         foreach ($attempts as $attempt) {
             $steps = $DB->get_records('question_attempt_steps', ['questionattemptid' => $attempt->id]);
             foreach ($steps as $step) {
@@ -116,67 +121,123 @@ public function anonymize_answers() {
                 $DB->update_record('question_attempt_steps', $step);
             }
         }
-        $this->data->userid = null;
+        $this->userid = null;
         $this->save();
     }
 
     /**
-     * Saves the current attempt.
-     * @return bool
+     * Helper function to properly create a new attempt for a JazzQuiz session.
+     *
+     * @param jazzquiz_session $session
+     * @return jazzquiz_attempt
      */
-    public function save() {
+    public static function create(jazzquiz_session $session): jazzquiz_attempt {
+        global $DB, $USER;
+        $quba = question_engine::make_questions_usage_by_activity('mod_jazzquiz', $session->jazzquiz->context);
+        $quba->set_preferred_behaviour('immediatefeedback');
+        // TODO: Don't suppress the error if it becomes possible to save QUBAs without slots.
+        @question_engine::save_questions_usage_by_activity($quba);
+        $id = $DB->insert_record('jazzquiz_attempts', [
+            'sessionid' => $session->data->id,
+            'userid' => isguestuser($USER->id) ? null : $USER->id,
+            'questionengid' => $quba->get_id(),
+            'guestsession' => isguestuser($USER->id) ? $USER->sesskey : null,
+            'status' => self::NOTSTARTED,
+            'responded' => null,
+            'timestart' => time(),
+            'timefinish' => null,
+            'timemodified' => time(),
+        ]);
+        $attempt = self::get_by_id($id);
+        $attempt->create_missing_attempts($session);
+        return $attempt;
+    }
+
+    /**
+     * Helper function to properly load a JazzQuiz attempt by its ID.
+     *
+     * @param int $id
+     * @return jazzquiz_attempt
+     */
+    public static function get_by_id(int $id): jazzquiz_attempt {
         global $DB;
+        $record = $DB->get_record('jazzquiz_attempts', ['id' => $id], '*', MUST_EXIST);
+        return new jazzquiz_attempt($record);
+    }
 
-        // Save the question usage by activity object.
-        if ($this->quba->question_count() > 0) {
-            \question_engine::save_questions_usage_by_activity($this->quba);
-        } else {
-            // TODO: Don't suppress the error if it becomes possible to save QUBAs without slots.
-            @\question_engine::save_questions_usage_by_activity($this->quba);
+    /**
+     * Helper function to properly load a JazzQuiz attempt for the current user in a session.
+     *
+     * @param jazzquiz_session $session
+     * @return jazzquiz_attempt
+     */
+    public static function get_by_session_for_current_user(jazzquiz_session $session): jazzquiz_attempt {
+        global $DB, $USER;
+        $sql = 'SELECT *
+                  FROM {jazzquiz_attempts}
+                 WHERE sessionid = :sessionid
+                   AND (userid = :userid OR guestsession = :sesskey)';
+        $record = $DB->get_record_sql($sql, [
+            'sessionid' => $session->data->id,
+            'userid' => $USER->id,
+            'sesskey' => $USER->sesskey,
+        ]);
+        if (empty($record)) {
+            return self::create($session);
         }
+        return new jazzquiz_attempt($record);
+    }
 
-        // Add the quba id as the questionengid.
-        // This is here because for new usages there is no id until we save it.
-        $this->data->questionengid = $this->quba->get_id();
-        $this->data->timemodified = time();
-        try {
-            if (isset($this->data->id)) {
-                $DB->update_record('jazzquiz_attempts', $this->data);
-            } else {
-                $this->data->id = $DB->insert_record('jazzquiz_attempts', $this->data);
-            }
-        } catch (\Exception $e) {
-            return false;
+    /**
+     * Save attempt.
+     */
+    public function save(): void {
+        global $DB;
+        if ($this->quba->question_count() > 0) {
+            question_engine::save_questions_usage_by_activity($this->quba);
         }
-        return true;
+        $this->timemodified = time();
+        $DB->update_record('jazzquiz_attempts', [
+            'id' => $this->id,
+            'sessionid' => $this->sessionid,
+            'userid' => $this->userid,
+            'questionengid' => $this->questionengid,
+            'guestsession' => $this->guestsession,
+            'status' => $this->status,
+            'responded' => $this->responded,
+            'timestart' => $this->timestart,
+            'timefinish' => $this->timefinish,
+            'timemodified' => $this->timemodified,
+        ]);
     }
 
     /**
-     * Saves a question attempt from the jazzquiz question
+     * Saves a question attempt from the jazzquiz question.
+     *
      * @param int $slot
      */
-    public function save_question($slot) {
+    public function save_question(int $slot): void {
         global $DB;
         $transaction = $DB->start_delegated_transaction();
         $this->quba->process_all_actions();
         $this->quba->finish_question($slot, time());
-        $this->data->timemodified = time();
-        $this->data->responded = 1;
+        $this->timemodified = time();
+        $this->responded = 1;
         $this->save();
         $transaction->allow_commit();
     }
 
     /**
-     * Gets the feedback for the specified question slot
+     * Gets the feedback for the specified question slot.
      *
      * If no slot is defined, we attempt to get that from the slots param passed
-     * back from the form submission
+     * back from the form submission.
      *
      * @param jazzquiz $jazzquiz
      * @param int $slot The slot for which we want to get feedback
      * @return string HTML fragment of the feedback
      */
-    public function get_question_feedback(jazzquiz $jazzquiz, $slot = -1) {
+    public function get_question_feedback(jazzquiz $jazzquiz, int $slot = -1): string {
         global $PAGE;
         if ($slot === -1) {
             // Attempt to get it from the slots param sent back from a question processing.
@@ -191,21 +252,23 @@ public function get_question_feedback(jazzquiz $jazzquiz, $slot = -1) {
     }
 
     /**
-     * Returns whether current user has responded
+     * Returns whether current user has responded.
+     *
      * @param int $slot
      * @return bool
      */
-    public function has_responded($slot) {
-        $response = $this->quba->get_question_attempt($slot)->get_response_summary();
-        return $response !== null && $response !== '';
+    public function has_responded(int $slot): bool {
+        $questionattempt = $this->quba->get_question_attempt($slot);
+        return !empty($questionattempt->get_response_summary());
     }
 
     /**
-     * Returns response data as an array
+     * Returns response data as an array.
+     *
      * @param int $slot
      * @return string[]
      */
-    public function get_response_data($slot) {
+    public function get_response_data(int $slot): array {
         $questionattempt = $this->quba->get_question_attempt($slot);
         $response = $questionattempt->get_response_summary();
         if ($response === null || $response === '') {
@@ -227,20 +290,26 @@ public function get_response_data($slot) {
     }
 
     /**
-     * Closes the attempt
+     * Closes the attempt.
+     *
      * @param jazzquiz $jazzquiz
      */
-    public function close_attempt(jazzquiz $jazzquiz) {
+    public function close_attempt(jazzquiz $jazzquiz): void {
         $this->quba->finish_all_questions(time());
         // We want the instructor to remain in preview mode.
         if (!$jazzquiz->is_instructor()) {
-            $this->data->status = self::FINISHED;
+            $this->status = self::FINISHED;
         }
-        $this->data->timefinish = time();
+        $this->timefinish = time();
         $this->save();
     }
 
-    public function total_answers() : int {
+    /**
+     * Get total answers.
+     *
+     * @return int
+     */
+    public function total_answers(): int {
         $count = 0;
         foreach ($this->quba->get_slots() as $slot) {
             if ($this->has_responded($slot)) {
diff --git a/classes/jazzquiz_question.php b/classes/jazzquiz_question.php
index b1b3364..f04a7ab 100755
--- a/classes/jazzquiz_question.php
+++ b/classes/jazzquiz_question.php
@@ -16,7 +16,7 @@
 
 namespace mod_jazzquiz;
 
-defined('MOODLE_INTERNAL') || die();
+use stdClass;
 
 /**
  * @package     mod_jazzquiz
@@ -26,23 +26,23 @@
  */
 class jazzquiz_question {
 
-    /** @var \stdClass $data */
-    public $data;
+    /** @var stdClass $data */
+    public stdClass $data;
 
-    /** @var \stdClass $question Question definition data */
-    public $question;
+    /** @var ?stdClass $question Question definition data */
+    public ?stdClass $question;
 
     /**
-     * @param \stdClass $data jazzquiz_question
+     * @param stdClass $data jazzquiz_question
      */
-    public function __construct(\stdClass $data) {
+    public function __construct(stdClass $data) {
         global $DB;
         $this->data = $data;
-        $this->question = $DB->get_record('question', ['id' => $data->questionid]);
+        $this->question = $DB->get_record('question', ['id' => $data->questionid]) ?: null;
     }
 
-    public function is_valid() {
-        return $this->question !== false;
+    public function is_valid(): bool {
+        return $this->question !== null;
     }
 
 }
diff --git a/classes/jazzquiz_session.php b/classes/jazzquiz_session.php
index b2bbe27..aaaf530 100755
--- a/classes/jazzquiz_session.php
+++ b/classes/jazzquiz_session.php
@@ -16,7 +16,9 @@
 
 namespace mod_jazzquiz;
 
-defined('MOODLE_INTERNAL') || die();
+use qubaid_join;
+use question_engine;
+use stdClass;
 
 /**
  * @package   mod_jazzquiz
@@ -28,39 +30,41 @@
 class jazzquiz_session {
 
     /** @var jazzquiz $jazzquiz */
-    public $jazzquiz;
+    public jazzquiz $jazzquiz;
 
-    /** @var \stdClass $data The jazzquiz_session database table row */
-    public $data;
+    /** @var stdClass $data The jazzquiz_session database table row */
+    public stdClass $data;
 
     /** @var jazzquiz_attempt[] */
-    public $attempts;
+    public array $attempts;
 
-    /** @var jazzquiz_attempt|false $attempt The current user's quiz attempt. False if not loaded. */
-    public $attempt;
+    /** @var ?jazzquiz_attempt The current user's quiz attempt */
+    public ?jazzquiz_attempt $myattempt;
 
-    /** @var \stdClass[] jazzquiz_session_questions */
-    public $questions;
+    /** @var stdClass[] Questions in this session */
+    public array $questions;
 
     /**
      * Constructor.
+     *
      * @param jazzquiz $jazzquiz
      * @param int $sessionid
      */
-    public function __construct(jazzquiz $jazzquiz, $sessionid) {
+    public function __construct(jazzquiz $jazzquiz, int $sessionid) {
         global $DB;
         $this->jazzquiz = $jazzquiz;
         $this->attempts = [];
-        $this->attempt = false;
+        $this->myattempt = null;
         $this->questions = [];
         $this->data = $DB->get_record('jazzquiz_sessions', [
             'jazzquizid' => $this->jazzquiz->data->id,
-            'id' => $sessionid
+            'id' => $sessionid,
         ], '*', MUST_EXIST);
     }
 
     /**
      * Get array of unasked slots.
+     *
      * @return int[] question slots.
      */
     public function get_unasked_slots() : array {
@@ -80,57 +84,51 @@ public function get_unasked_slots() : array {
         return $slots;
     }
 
-    private function requires_anonymous_answers() {
+    /**
+     * @return bool
+     */
+    private function requires_anonymous_answers(): bool {
         return $this->data->anonymity != 3;
     }
 
-    private function requires_anonymous_attendance() {
+    /**
+     * @return bool
+     */
+    private function requires_anonymous_attendance(): bool {
         return $this->data->anonymity == 2;
     }
 
     /**
-     * Saves the session object to the database
-     * @return bool
+     * Saves the session object to the database.
      */
-    public function save() {
+    public function save(): void {
         global $DB;
-        // Update if we already have a session, otherwise create it.
         if (isset($this->data->id)) {
-            try {
-                $DB->update_record('jazzquiz_sessions', $this->data);
-            } catch (\Exception $e) {
-                return false;
-            }
+            $DB->update_record('jazzquiz_sessions', $this->data);
         } else {
-            try {
-                $this->data->id = $DB->insert_record('jazzquiz_sessions', $this->data);
-            } catch (\Exception $e) {
-                return false;
-            }
+            $this->data->id = $DB->insert_record('jazzquiz_sessions', $this->data);
         }
-        return true;
     }
 
     /**
      * Deletes the specified session, as well as the attempts.
+     *
      * @param int $sessionid
-     * @return bool
      */
-    public static function delete($sessionid) {
+    public static function delete(int $sessionid): void {
         global $DB;
         // Delete all attempt quba ids, then all JazzQuiz attempts, and then finally itself.
-        $condition = new \qubaid_join('{jazzquiz_attempts} jqa', 'jqa.questionengid', 'jqa.sessionid = :sessionid', [
-            'sessionid' => $sessionid
+        $condition = new qubaid_join('{jazzquiz_attempts} jqa', 'jqa.questionengid', 'jqa.sessionid = :sessionid', [
+            'sessionid' => $sessionid,
         ]);
-        \question_engine::delete_questions_usage_by_activities($condition);
+        question_engine::delete_questions_usage_by_activities($condition);
         $DB->delete_records('jazzquiz_attempts', ['sessionid' => $sessionid]);
         $DB->delete_records('jazzquiz_session_questions', ['sessionid' => $sessionid]);
         $DB->delete_records('jazzquiz_votes', ['sessionid' => $sessionid]);
         $DB->delete_records('jazzquiz_sessions', ['id' => $sessionid]);
-        return true;
     }
 
-    public function user_name_for_answer($userid) {
+    public function user_name_for_answer($userid): string {
         global $DB;
         if ($this->requires_anonymous_answers() || is_null($userid)) {
             return get_string('anonymous', 'jazzquiz');
@@ -142,7 +140,7 @@ public function user_name_for_answer($userid) {
         return $user->lastname . ', ' . $user->firstname;
     }
 
-    public function user_name_for_attendance($userid) {
+    public function user_name_for_attendance($userid): string {
         global $DB;
         if ($this->requires_anonymous_attendance() || is_null($userid)) {
             return get_string('anonymous', 'jazzquiz');
@@ -154,7 +152,13 @@ public function user_name_for_attendance($userid) {
         return $user->lastname . ', ' . $user->firstname;
     }
 
-    public function user_idnumber_for_attendance($userid) {
+    /**
+     * Get user ID for attendance.
+     *
+     * @param ?int $userid
+     * @return string
+     */
+    public function user_idnumber_for_attendance(?int $userid): string {
         global $DB;
         if ($this->requires_anonymous_attendance() || is_null($userid)) {
             return get_string('anonymous', 'jazzquiz');
@@ -170,7 +174,7 @@ public function user_idnumber_for_attendance($userid) {
      * Anonymize attendance, making it unknown how many questions each user has answered.
      * Only makes sense to do this along with anonymizing answers. This should be called first.
      */
-    private function anonymize_attendance() {
+    private function anonymize_attendance(): void {
         global $DB;
         $attendances = $DB->get_records('jazzquiz_attendance', ['sessionid' => $this->data->id]);
         foreach ($attendances as $attendance) {
@@ -179,11 +183,11 @@ private function anonymize_attendance() {
         }
     }
 
-    private function anonymize_users() {
+    private function anonymize_users(): void {
         if ($this->requires_anonymous_attendance()) {
             $this->anonymize_attendance();
         }
-        foreach ($this->attempts as &$attempt) {
+        foreach ($this->attempts as $attempt) {
             if ($this->requires_anonymous_answers()) {
                 $attempt->anonymize_answers();
             }
@@ -192,9 +196,8 @@ private function anonymize_users() {
 
     /**
      * Closes the attempts and ends the session.
-     * @return bool Whether or not this was successful
      */
-    public function end_session() {
+    public function end_session(): void {
         $this->anonymize_users();
         $this->data->status = 'notrunning';
         $this->data->sessionopen = 0;
@@ -203,23 +206,24 @@ public function end_session() {
         foreach ($this->attempts as $attempt) {
             $attempt->close_attempt($this->jazzquiz);
         }
-        return $this->save();
+        $this->save();
     }
 
     /**
      * Merge responses with 'from' to 'into'
+     *
      * @param int $slot Session question slot
      * @param string $from Original response text
      * @param string $into Merged response text
      */
-    public function merge_responses($slot, string $from, string $into) {
+    public function merge_responses(int $slot, string $from, string $into): void {
         global $DB;
-        $merge = new \stdClass();
+        $merge = new stdClass();
         $merge->sessionid = $this->data->id;
         $merge->slot = $slot;
         $merge->ordernum = count($DB->get_records('jazzquiz_merges', [
             'sessionid' => $this->data->id,
-            'slot' => $slot
+            'slot' => $slot,
         ]));
         $merge->original = $from;
         $merge->merged = $into;
@@ -230,11 +234,11 @@ public function merge_responses($slot, string $from, string $into) {
      * Undo the last merge of the specified question.
      * @param int $slot Session question slot
      */
-    public function undo_merge($slot) {
+    public function undo_merge(int $slot): void {
         global $DB;
         $merge = $DB->get_records('jazzquiz_merges', [
             'sessionid' => $this->data->id,
-            'slot' => $slot
+            'slot' => $slot,
         ], 'ordernum desc', '*', 0, 1);
         if (count($merge) > 0) {
             $merge = reset($merge);
@@ -244,15 +248,16 @@ public function undo_merge($slot) {
 
     /**
      * Get the merged responses.
+     *
      * @param int $slot Session question slot
-     * @param string[]['response'] $responses Original responses
-     * @return string[]['response'], int Merged responses and count of merges.
+     * @param array[] $responses 'response' contains original response
+     * @return int[]|string[] Merged responses and count of merges.
      */
-    public function get_merged_responses($slot, array $responses) : array {
+    public function get_merged_responses(int $slot, array $responses) : array {
         global $DB;
         $merges = $DB->get_records('jazzquiz_merges', [
             'sessionid' => $this->data->id,
-            'slot' => $slot
+            'slot' => $slot,
         ]);
         $count = 0;
         foreach ($merges as $merge) {
@@ -268,16 +273,17 @@ public function get_merged_responses($slot, array $responses) : array {
 
     /**
      * Tells the session to go to the specified question number
-     * That jazzquiz_question is then returned
+     * That jazzquiz_question is then returned.
+     *
      * @param int $questionid (from question bank)
      * @param int $questiontime in seconds ("<0" => no time, "0" => default)
-     * @return mixed[] $success, $question_time
+     * @return array $success, $question_time
      */
-    public function start_question($questionid, $questiontime) {
+    public function start_question(int $questionid, int $questiontime): array {
         global $DB;
         $transaction = $DB->start_delegated_transaction();
 
-        $sessionquestion = new \stdClass();
+        $sessionquestion = new stdClass();
         $sessionquestion->sessionid = $this->data->id;
         $sessionquestion->questionid = $questionid;
         $sessionquestion->questiontime = $questiontime;
@@ -285,7 +291,7 @@ public function start_question($questionid, $questiontime) {
         $sessionquestion->id = $DB->insert_record('jazzquiz_session_questions', $sessionquestion);
         $this->questions[$sessionquestion->slot] = $sessionquestion;
 
-        foreach ($this->attempts as &$attempt) {
+        foreach ($this->attempts as $attempt) {
             $attempt->create_missing_attempts($this);
             $attempt->save();
         }
@@ -301,52 +307,39 @@ public function start_question($questionid, $questiontime) {
     /**
      * Create a quiz attempt for the current user.
      */
-    public function initialize_attempt() {
+    public function initialize_attempt(): void {
         global $USER;
         // Check if this user has already joined the quiz.
-        foreach ($this->attempts as &$attempt) {
-            if ($attempt->data->userid == $USER->id) {
+        foreach ($this->attempts as $attempt) {
+            if ($attempt->userid == $USER->id) {
                 $attempt->create_missing_attempts($this);
                 $attempt->save();
-                $this->attempt = $attempt;
+                $this->myattempt = $attempt;
                 return;
             }
         }
         // For users who have not yet joined the quiz.
-        $this->attempt = new jazzquiz_attempt($this->jazzquiz->context);
-        $this->attempt->data->sessionid = $this->data->id;
-        if (isguestuser($USER->id)) {
-            $this->attempt->data->guestsession = $USER->sesskey;
-        } else {
-            $this->attempt->data->userid = $USER->id;
-        }
-        $this->attempt->data->status = jazzquiz_attempt::NOTSTARTED;
-        $this->attempt->data->timemodified = time();
-        $this->attempt->data->timestart = time();
-        $this->attempt->data->responded = null;
-        $this->attempt->data->timefinish = null;
-        $this->attempt->create_missing_attempts($this);
-        $this->attempt->save();
+        $this->myattempt = jazzquiz_attempt::create($this);
     }
 
-    public function update_attendance_for_current_user() {
+    public function update_attendance_for_current_user(): void {
         global $DB, $USER;
         if (isguestuser($USER->id)) {
             return;
         }
-        $numresponses = $this->attempt->total_answers();
+        $numresponses = $this->myattempt->total_answers();
         if ($numresponses === 0) {
             return;
         }
         $attendance = $DB->get_record('jazzquiz_attendance', [
             'sessionid' => $this->data->id,
-            'userid' => $USER->id
+            'userid' => $USER->id,
         ]);
         if ($attendance) {
             $attendance->numresponses = $numresponses;
             $DB->update_record('jazzquiz_attendance', $attendance);
         } else {
-            $attendance = new \stdClass();
+            $attendance = new stdClass();
             $attendance->sessionid = $this->data->id;
             $attendance->userid = $USER->id;
             $attendance->numresponses = $numresponses;
@@ -357,40 +350,25 @@ public function update_attendance_for_current_user() {
     /**
      * Load all the attempts for this session.
      */
-    public function load_attempts() {
+    public function load_attempts(): void {
         global $DB;
         $this->attempts = [];
-        $attempts = $DB->get_records('jazzquiz_attempts', ['sessionid' => $this->data->id]);
-        foreach ($attempts as $attempt) {
-            $this->attempts[$attempt->id] = new jazzquiz_attempt($this->jazzquiz->context, $attempt);
+        foreach ($DB->get_records('jazzquiz_attempts', ['sessionid' => $this->data->id]) as $attempt) {
+            $this->attempts[$attempt->id] = jazzquiz_attempt::get_by_id($attempt->id);
         }
     }
 
     /**
      * Load the current attempt for the user.
      */
-    public function load_attempt() {
-        global $DB, $USER;
-        $sql = 'SELECT *
-                  FROM {jazzquiz_attempts}
-                 WHERE sessionid = :sessionid
-                   AND (userid = :userid OR guestsession = :sesskey)';
-        $attempt = $DB->get_record_sql($sql, [
-            'sessionid' => $this->data->id,
-            'userid' => $USER->id,
-            'sesskey' => $USER->sesskey
-        ]);
-        if (!$attempt) {
-            $this->attempt = false;
-            return;
-        }
-        $this->attempt = new jazzquiz_attempt($this->jazzquiz->context, $attempt);
+    public function load_my_attempt(): void {
+        $this->myattempt = jazzquiz_attempt::get_by_session_for_current_user($this);
     }
 
     /**
      * Load all the session questions.
      */
-    public function load_session_questions() {
+    public function load_session_questions(): void {
         global $DB;
         $this->questions = $DB->get_records('jazzquiz_session_questions', ['sessionid' => $this->data->id], 'slot');
         foreach ($this->questions as $question) {
@@ -400,15 +378,16 @@ public function load_session_questions() {
     }
 
     /**
-     * Get the user IDs for who have attempted this session
+     * Get the user IDs for who have attempted this session.
+     *
      * @return int[] user IDs that have attempted this session
      */
-    public function get_users() {
+    public function get_users(): array {
         $users = [];
         foreach ($this->attempts as $attempt) {
             // Preview attempt means it's an instructor.
-            if ($attempt->data->status != jazzquiz_attempt::PREVIEW) {
-                $users[] = isguestuser($attempt->data->userid) ? null : $attempt->data->userid;
+            if ($attempt->status != jazzquiz_attempt::PREVIEW) {
+                $users[] = isguestuser($attempt->userid) ? null : $attempt->userid;
             }
         }
         return $users;
@@ -416,9 +395,10 @@ public function get_users() {
 
     /**
      * Get the total number of students participating in the quiz.
+     *
      * @return int
      */
-    public function get_student_count() {
+    public function get_student_count(): int {
         $count = count($this->attempts);
         if ($count > 0) {
             $count--; // The instructor also has an attempt.
@@ -430,19 +410,20 @@ public function get_student_count() {
 
     /**
      * Get the correct answer rendered in HTML.
+     *
      * @return string HTML
      */
-    public function get_question_right_response() {
+    public function get_question_right_response(): string {
         // Use the current user's attempt to render the question with the right response.
-        $quba = $this->attempt->quba;
+        $quba = $this->myattempt->quba;
         $slot = count($this->questions);
         $correctresponse = $quba->get_correct_response($slot);
         if (is_null($correctresponse)) {
             return 'No correct response';
         }
         $quba->process_action($slot, $correctresponse);
-        $this->attempt->save();
-        $reviewoptions = new \stdClass();
+        $this->myattempt->save();
+        $reviewoptions = new stdClass();
         $reviewoptions->rightanswer = 1;
         $reviewoptions->correctness = 1;
         $reviewoptions->specificfeedback = 1;
@@ -450,21 +431,22 @@ public function get_question_right_response() {
         /** @var output\renderer $renderer */
         $renderer = $this->jazzquiz->renderer;
         ob_start();
-        $html = $renderer->render_question($this->jazzquiz, $this->attempt->quba, $slot, true, $reviewoptions);
+        $html = $renderer->render_question($this->jazzquiz, $this->myattempt->quba, $slot, true, $reviewoptions);
         $htmlechoed = ob_get_clean();
         return $html . $htmlechoed;
     }
 
     /**
-     * Gets the results of the current question as an array
+     * Gets the results of the current question as an array.
+     *
      * @param int $slot
      * @return array
      */
-    public function get_question_results_list($slot) {
+    public function get_question_results_list(int $slot): array {
         $responses = [];
         $responded = 0;
         foreach ($this->attempts as $attempt) {
-            if ($attempt->data->responded != 1) {
+            if ($attempt->responded != 1) {
                 continue;
             }
             $attemptresponses = $attempt->get_response_data($slot);
@@ -477,11 +459,11 @@ public function get_question_results_list($slot) {
         return [
             'responses' => $responses,
             'responded' => $responded,
-            'student_count' => $this->get_student_count()
+            'student_count' => $this->get_student_count(),
         ];
     }
 
-    public function get_attendances() : array {
+    public function get_attendances(): array {
         global $DB;
         $attendances = [];
         $records = $DB->get_records('jazzquiz_attendance', ['sessionid' => $this->data->id]);
@@ -489,14 +471,14 @@ public function get_attendances() : array {
             $attendances[] = [
                 'idnumber' => $this->user_idnumber_for_attendance($record->userid),
                 'name' => $this->user_name_for_attendance($record->userid),
-                'count' => $record->numresponses
+                'count' => $record->numresponses,
             ];
         }
         foreach ($this->attempts as $attempt) {
-            if (!$attempt->data->userid && $attempt->data->guestsession) {
+            if (!$attempt->userid && $attempt->guestsession) {
                 $attendances[] = [
                     'name' => get_string('anonymous', 'jazzquiz'),
-                    'count' => $attempt->total_answers()
+                    'count' => $attempt->total_answers(),
                 ];
             }
         }
@@ -505,10 +487,11 @@ public function get_attendances() : array {
 
     /**
      * @todo Temporary function. Should be removed at a later time.
+     *
      * @param int $slot
      * @return string
      */
-    public function get_question_type_by_slot($slot) : string {
+    public function get_question_type_by_slot(int $slot) : string {
         global $DB;
         $id = $this->questions[$slot]->questionid;
         $question = $DB->get_record('question', ['id' => $id], 'qtype');
diff --git a/classes/jazzquiz_vote.php b/classes/jazzquiz_vote.php
index d8d7ee0..4845717 100755
--- a/classes/jazzquiz_vote.php
+++ b/classes/jazzquiz_vote.php
@@ -16,7 +16,7 @@
 
 namespace mod_jazzquiz;
 
-defined('MOODLE_INTERNAL') || die();
+use stdClass;
 
 /**
  * @package     mod_jazzquiz
@@ -27,39 +27,41 @@
 class jazzquiz_vote {
 
     /** @var int $sessionid */
-    protected $sessionid;
+    protected int $sessionid;
 
     /** @var int $slot */
-    protected $slot;
+    protected int $slot;
 
     /**
      * Constructor.
+     *
      * @param int $sessionid
      * @param int $slot
      */
-    public function __construct($sessionid, $slot = 0) {
+    public function __construct(int $sessionid, int $slot = 0) {
         $this->sessionid = $sessionid;
         $this->slot = $slot;
     }
 
     /**
      * Get the results for the vote.
+     *
      * @return array
      */
-    public function get_results() {
+    public function get_results(): array {
         global $DB;
-        $votes = $DB->get_records('jazzquiz_votes', [
+        return $DB->get_records('jazzquiz_votes', [
             'sessionid' => $this->sessionid,
-            'slot' => $this->slot
+            'slot' => $this->slot,
         ]);
-        return $votes;
     }
 
     /**
      * Check whether a user has voted or not.
+     *
      * @return bool
      */
-    public function has_user_voted() {
+    public function has_user_voted(): bool {
         global $DB, $USER;
         $allvotes = $DB->get_records('jazzquiz_votes', ['sessionid' => $this->sessionid]);
         if (!$allvotes) {
@@ -81,10 +83,11 @@ public function has_user_voted() {
 
     /**
      * Save the vote for a user.
+     *
      * @param int $voteid
      * @return bool
      */
-    public function save_vote($voteid) {
+    public function save_vote(int $voteid): bool {
         global $DB, $USER;
         if ($this->has_user_voted()) {
             return false;
@@ -109,12 +112,13 @@ public function save_vote($voteid) {
 
     /**
      * Insert the options for the vote.
+     *
      * @param int $jazzquizid
      * @param string $qtype
      * @param array $options
      * @param int $slot
      */
-    public function prepare_options($jazzquizid, string $qtype, array $options, $slot) {
+    public function prepare_options(int $jazzquizid, string $qtype, array $options, int $slot) {
         global $DB;
 
         // Delete previous voting options for this session.
@@ -122,7 +126,7 @@ public function prepare_options($jazzquizid, string $qtype, array $options, $slo
 
         // Add to database.
         foreach ($options as $option) {
-            $vote = new \stdClass();
+            $vote = new stdClass();
             $vote->jazzquizid = $jazzquizid;
             $vote->sessionid = $this->sessionid;
             $vote->attempt = $option['text'];
diff --git a/classes/local/page_requirements_diff.php b/classes/local/page_requirements_diff.php
new file mode 100644
index 0000000..319d901
--- /dev/null
+++ b/classes/local/page_requirements_diff.php
@@ -0,0 +1,79 @@
+<?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/>.
+
+namespace mod_jazzquiz\local;
+
+use page_requirements_manager;
+
+/**
+ * To load a question without refreshing the page, we need the JavaScript for the question.
+ * Moodle stores this in page_requirements_manager, but there is no way to read the JS that is required.
+ * This class takes in the manager and keeps the JS for when we want to get a diff.
+ * NOTE: This class is placed here because it will only ever be used by renderer::render_question_form()
+ * TODO: Look into removing this class in the future.
+ *
+ * @package   mod_jazzquiz
+ * @author    Sebastian S. Gundersen <sebastian@sgundersen.com>
+ * @copyright 2018 NTNU
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class page_requirements_diff extends page_requirements_manager {
+
+    /** @var array $beforeinitjs */
+    private array $beforeinitjs;
+
+    /** @var array $beforeamdjs */
+    private array $beforeamdjs;
+
+    /** @var array $beforecss */
+    private array $beforecss;
+
+    /**
+     * Constructor.
+     *
+     * @param page_requirements_manager $manager
+     */
+    public function __construct(page_requirements_manager $manager) {
+        $this->beforeinitjs = $manager->jsinitcode;
+        $this->beforeamdjs = $manager->amdjscode;
+        $this->beforecss = $manager->cssurls;
+    }
+
+    /**
+     * Run an array_diff on the required JavaScript when this
+     * was constructed and the one passed to this function.
+     *
+     * @param page_requirements_manager $manager
+     * @return array the JavaScript that was added in-between constructor and this call.
+     */
+    public function get_js_diff(page_requirements_manager $manager): array {
+        $jsinitcode = array_diff($manager->jsinitcode, $this->beforeinitjs);
+        $amdjscode = array_diff($manager->amdjscode, $this->beforeamdjs);
+        return array_merge($jsinitcode, $amdjscode);
+    }
+
+    /**
+     * Run an array_diff on the required CSS when this
+     * was constructed and the one passed to this function.
+     *
+     * @param page_requirements_manager $manager
+     * @return array the CSS that was added in-between constructor and this call.
+     */
+    public function get_css_diff(page_requirements_manager $manager): array {
+        return array_keys(array_diff($manager->cssurls, $this->beforecss));
+    }
+
+}
diff --git a/classes/output/renderer.php b/classes/output/renderer.php
index cc91f67..6f88602 100755
--- a/classes/output/renderer.php
+++ b/classes/output/renderer.php
@@ -16,71 +16,21 @@
 
 namespace mod_jazzquiz\output;
 
+use html_writer;
 use mod_jazzquiz\forms\view\student_start_form;
 use mod_jazzquiz\jazzquiz;
 use mod_jazzquiz\jazzquiz_attempt;
 use mod_jazzquiz\jazzquiz_session;
+use mod_jazzquiz\local\page_requirements_diff;
+use moodle_url;
+use moodleform;
+use question_usage_by_activity;
+use stdClass;
 
 defined('MOODLE_INTERNAL') || die;
 
 require_once($CFG->libdir . '/questionlib.php');
 
-/**
- * To load a question without refreshing the page, we need the JavaScript for the question.
- * Moodle stores this in page_requirements_manager, but there is no way to read the JS that is required.
- * This class takes in the manager and keeps the JS for when we want to get a diff.
- * NOTE: This class is placed here because it will only ever be used by renderer::render_question_form()
- * TODO: Look into removing this class in the future.
- * @package   mod_jazzquiz\output
- * @author    Sebastian S. Gundersen <sebastian@sgundersen.com>
- * @copyright 2018 NTNU
- * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
-class page_requirements_diff extends \page_requirements_manager {
-
-    /** @var array $beforeinitjs */
-    private $beforeinitjs;
-
-    /** @var array $beforeamdjs */
-    private $beforeamdjs;
-
-    /** @var array $beforecss */
-    private $beforecss;
-
-    /**
-     * Constructor.
-     * @param \page_requirements_manager $manager
-     */
-    public function __construct(\page_requirements_manager $manager) {
-        $this->beforeinitjs = $manager->jsinitcode;
-        $this->beforeamdjs = $manager->amdjscode;
-        $this->beforecss = $manager->cssurls;
-    }
-
-    /**
-     * Run an array_diff on the required JavaScript when this
-     * was constructed and the one passed to this function.
-     * @param \page_requirements_manager $manager
-     * @return array the JavaScript that was added in-between constructor and this call.
-     */
-    public function get_js_diff(\page_requirements_manager $manager) : array {
-        $jsinitcode = array_diff($manager->jsinitcode, $this->beforeinitjs);
-        $amdjscode = array_diff($manager->amdjscode, $this->beforeamdjs);
-        return array_merge($jsinitcode, $amdjscode);
-    }
-
-    /**
-     * Run an array_diff on the required CSS when this
-     * was constructed and the one passed to this function.
-     * @param \page_requirements_manager $manager
-     * @return array the CSS that was added in-between constructor and this call.
-     */
-    public function get_css_diff(\page_requirements_manager $manager) : array {
-        return array_keys(array_diff($manager->cssurls, $this->beforecss));
-    }
-
-}
-
 /**
  * Quiz renderer
  *
@@ -94,10 +44,11 @@ class renderer extends \plugin_renderer_base {
 
     /**
      * Render the header for the page.
+     *
      * @param jazzquiz $jazzquiz
      * @param string $tab The active tab on the page
      */
-    public function header(jazzquiz $jazzquiz, string $tab) {
+    public function header(jazzquiz $jazzquiz, string $tab): void {
         echo $this->output->header();
         echo jazzquiz_view_tabs($jazzquiz, $tab);
     }
@@ -105,23 +56,25 @@ public function header(jazzquiz $jazzquiz, string $tab) {
     /**
      * Render the footer for the page.
      */
-    public function footer() {
+    public function footer(): void {
         echo $this->output->footer();
     }
 
     /**
      * For instructors.
-     * @param \moodleform $sessionform
+     *
+     * @param moodleform $sessionform
      */
-    public function start_session_form(\moodleform $sessionform) {
+    public function start_session_form(moodleform $sessionform): void {
         echo $this->render_from_template('jazzquiz/start_session', ['form' => $sessionform->render()]);
     }
 
     /**
      * For instructors.
+     *
      * @param jazzquiz $jazzquiz
      */
-    public function continue_session_form(jazzquiz $jazzquiz) {
+    public function continue_session_form(jazzquiz $jazzquiz): void {
         $cmid = $jazzquiz->cm->id;
         $id = $jazzquiz->data->id;
         echo $this->render_from_template('jazzquiz/continue_session', [
@@ -131,43 +84,39 @@ public function continue_session_form(jazzquiz $jazzquiz) {
 
     /**
      * Show the "join quiz" form for students.
+     *
      * @param student_start_form $form
      * @param jazzquiz_session $session
-     * @throws \moodle_exception
      */
-    public function join_quiz_form(student_start_form $form, jazzquiz_session $session) {
+    public function join_quiz_form(student_start_form $form, jazzquiz_session $session): void {
         $anonstr = ['', 'anonymous_answers_info', 'fully_anonymous_info', 'nonanonymous_session_info'];
         echo $this->render_from_template('jazzquiz/join_session', [
             'name' => $session->data->name,
-            'started' => ($session->attempt !== false),
+            'started' => $session->myattempt !== false,
             'anonymity_info' => get_string($anonstr[$session->data->anonymity], 'jazzquiz'),
-            'form' => $form->render()
+            'form' => $form->render(),
         ]);
     }
 
     /**
      * Show the "quiz not running" page for students.
+     *
      * @param int $cmid the course module id for the quiz
-     * @throws \moodle_exception
      */
-    public function quiz_not_running($cmid) {
+    public function quiz_not_running(int $cmid): void {
         echo $this->render_from_template('jazzquiz/no_session', [
-            'reload' => $this->page->url->get_path() . '?id=' . $cmid
+            'reload' => $this->page->url->get_path() . "?id=$cmid",
         ]);
     }
 
 
     /**
-     * Shows the "guests not allowed" page when trying to access a
-     * quiz which does not allow guests in guest mode.
-     * @throws \moodle_exception
+     * Shows the "guests not allowed" page when trying to access a quiz which does not allow guests in guest mode.
      */
-    public function guests_not_allowed() {
+    public function guests_not_allowed(): void {
         echo $this->render_from_template('jazzquiz/guests_not_allowed', []);
     }
 
-
-
     /**
      * Renders the quiz to the page
      * @param jazzquiz_session $session
@@ -181,7 +130,7 @@ public function render_quiz(jazzquiz_session $session) {
                 $result[] = [
                     'icon' => $button[0],
                     'id' => $button[1],
-                    'text' => get_string($button[1], 'jazzquiz')
+                    'text' => get_string($button[1], 'jazzquiz'),
                 ];
             }
             return $result;
@@ -200,36 +149,37 @@ public function render_quiz(jazzquiz_session $session) {
                 ['square-o', 'responses'],
                 ['square-o', 'answer']
             ]),
-            'instructor' => $session->jazzquiz->is_instructor()
+            'instructor' => $session->jazzquiz->is_instructor(),
         ]);
     }
 
     /**
-     * Render the question specified by slot
+     * Render the question specified by slot.
+     *
      * @param jazzquiz $jazzquiz
-     * @param \question_usage_by_activity $quba
+     * @param question_usage_by_activity $quba
      * @param int $slot
-     * @param bool $review Whether or not we're reviewing the attempt
-     * @param string|\stdClass $reviewoptions Can be string for overall actions like "edit" or an object of review options
+     * @param bool $review Are we reviewing the attempt?
+     * @param string|stdClass $reviewoptions Can be string for overall actions like "edit" or an object of review options
      * @return string the HTML fragment for the question
      */
-    public function render_question(jazzquiz $jazzquiz, $quba, $slot, bool $review, $reviewoptions) : string {
+    public function render_question(jazzquiz $jazzquiz, question_usage_by_activity $quba, int $slot, bool $review, string|stdClass $reviewoptions): string {
         $displayoptions = $jazzquiz->get_display_options($review, $reviewoptions);
         $quba->render_question_head_html($slot);
         return $quba->render_question($slot, $displayoptions, $slot);
     }
 
     /**
-     * Render a specific question in its own form so it can be submitted
-     * independently of the rest of the questions
+     * Render a specific question in its own form, so it can be submitted
+     * independently of the rest of the questions.
+     *
      * @param int $slot the id of the question we're rendering
      * @param jazzquiz_attempt $attempt
      * @param jazzquiz $jazzquiz
      * @param bool $instructor
      * @return string[] html, javascript, css
-     * @throws \moodle_exception
      */
-    public function render_question_form($slot, jazzquiz_attempt $attempt, jazzquiz $jazzquiz, bool $instructor) : array {
+    public function render_question_form(int $slot, jazzquiz_attempt $attempt, jazzquiz $jazzquiz, bool $instructor): array {
         $differ = new page_requirements_diff($this->page->requires);
         ob_start();
         $questionhtml = $this->render_question($jazzquiz, $attempt->quba, $slot, false, '');
@@ -239,25 +189,23 @@ public function render_question_form($slot, jazzquiz_attempt $attempt, jazzquiz
         $output = $this->render_from_template('jazzquiz/question', [
             'instructor' => $instructor,
             'question' => $questionhtml . $questionhtmlechoed,
-            'slot' => $slot
+            'slot' => $slot,
         ]);
         return [$output, $js, $css];
     }
 
     /**
-     * Renders and echos the home page for the responses section
-     * @param \moodle_url $url
-     * @param \stdClass[] $sessions
+     * Renders and echos the home page for the responses section.
+     *
+     * @param moodle_url $url
+     * @param stdClass[] $sessions
      * @param int $selectedid
      * @return array
-     * @throws \coding_exception
      */
-    public function get_select_session_context(\moodle_url $url, array $sessions, $selectedid) : array {
+    public function get_select_session_context(\moodle_url $url, array $sessions, int $selectedid) : array {
         $selecturl = clone($url);
         $selecturl->param('action', 'view');
-        usort($sessions, function ($a, $b) {
-            return strcmp(strtolower($a->name), strtolower($b->name));
-        });
+        usort($sessions, fn(stdClass $a, stdClass $b) => strcmp(strtolower($a->name), strtolower($b->name)));
         return [
             'method' => 'get',
             'action' => $selecturl->out_omit_querystring(),
@@ -268,28 +216,28 @@ public function get_select_session_context(\moodle_url $url, array $sessions, $s
                 return [
                     'name' => $session->name,
                     'value' => $session->id,
-                    'selected' => intval($selectedid) === intval($session->id),
-                    'optgroup' => false
+                    'selected' => $selectedid === (int)$session->id,
+                    'optgroup' => false,
                 ];
             }, $sessions),
             'params' => array_map(function ($key, $value) {
                 return [
                     'name' => $key,
-                    'value' => $value
+                    'value' => $value,
                 ];
             }, array_keys($selecturl->params()), $selecturl->params()),
         ];
     }
 
     /**
-     * Render the list questions view for the edit page
+     * Render the list questions view for the edit page.
+     *
      * @param jazzquiz $jazzquiz
      * @param array $questions Array of questions
      * @param string $questionbankview HTML for the question bank view
-     * @param \moodle_url $url
-     * @throws \moodle_exception
+     * @param moodle_url $url
      */
-    public function list_questions(jazzquiz $jazzquiz, array $questions, string $questionbankview, \moodle_url $url) {
+    public function list_questions(jazzquiz $jazzquiz, array $questions, string $questionbankview, moodle_url $url): void {
         $slot = 1;
         $list = [];
         foreach ($questions as $question) {
@@ -303,28 +251,27 @@ public function list_questions(jazzquiz $jazzquiz, array $questions, string $que
                 'last' => $slot === count($questions),
                 'slot' => $slot,
                 'editurl' => $editurl,
-                'icon' => print_question_icon($question->question)
+                'icon' => print_question_icon($question->question),
             ];
             $slot++;
         }
         echo $this->render_from_template('jazzquiz/edit_question_list', [
             'questions' => $list,
-            'qbank' => $questionbankview
+            'qbank' => $questionbankview,
         ]);
         $this->require_edit($jazzquiz->cm->id);
     }
 
-    public function session_is_open_error() {
-        echo \html_writer::tag('h3', get_string('edit_page_open_session_error', 'jazzquiz'));
+    public function session_is_open_error(): void {
+        echo html_writer::tag('h3', get_string('edit_page_open_session_error', 'jazzquiz'));
     }
 
     /**
      * @param jazzquiz_session $session
-     * @param \moodle_url $url
-     * @return mixed[]
-     * @throws \coding_exception
+     * @param moodle_url $url
+     * @return array
      */
-    public function view_session_report(jazzquiz_session $session, \moodle_url $url) : array {
+    public function view_session_report(jazzquiz_session $session, \moodle_url $url): array {
         $attempt = reset($session->attempts);
         if (!$attempt) {
             $strnoattempts = get_string('no_attempts_found', 'jazzquiz');
@@ -342,7 +289,7 @@ public function view_session_report(jazzquiz_session $session, \moodle_url $url)
                 'name' => str_replace('{IMPROV}', '', $question->name),
                 'type' => $attempt->quba->get_question_attempt($qubaslot)->get_question()->get_type_name(),
                 'description' => $question->questiontext,
-                'responses' => $results['responses']
+                'responses' => $results['responses'],
             ];
         }
 
@@ -362,7 +309,7 @@ public function view_session_report(jazzquiz_session $session, \moodle_url $url)
                 'count_answered' => count($attendances),
                 'cmid' => $jazzquiz->cm->id,
                 'quizid' => $jazzquiz->data->id,
-                'id' => $session->data->id
+                'id' => $session->data->id,
             ]
         ];
     }
@@ -370,35 +317,22 @@ public function view_session_report(jazzquiz_session $session, \moodle_url $url)
     /**
      * @param jazzquiz_session $session
      */
-    public function require_core(jazzquiz_session $session) {
+    public function require_core(jazzquiz_session $session): void {
         $this->page->requires->js_call_amd('mod_jazzquiz/core', 'initialize', [
             $session->jazzquiz->cm->id,
             $session->jazzquiz->data->id,
             $session->data->id,
-            $session->attempt ? $session->attempt->data->id : 0,
-            sesskey()
+            $session->myattempt?->id ?? 0,
+            sesskey(),
         ]);
     }
 
     /**
      * @param jazzquiz_session $session
      */
-    public function require_quiz(jazzquiz_session $session) {
+    public function require_quiz(jazzquiz_session $session): void {
         $this->require_core($session);
-
-        // question/qengine.js is deprecated for Moodle versions after 401.
-        // Checks moodle version in order to determine which question engine
-        // to use, making the jazzquiz independent of the Moodle version.
-        global $CFG;
-        include $CFG->dirroot.'/version.php';
-        $branch = $CFG->branch;
-
-        if ( (int) $branch <= 401 ) {
-            $this->page->requires->js('/question/qengine.js');
-        } else {
-            $this->page->requires->js_call_amd('core_question/question_engine', 'initialize');
-        }
-        
+        $this->page->requires->js_call_amd('core_question/question_engine', 'initSubmitButton');
         if ($session->jazzquiz->is_instructor()) {
             $count = count($session->jazzquiz->questions);
             $params = [$count, false, []];
@@ -411,7 +345,7 @@ public function require_quiz(jazzquiz_session $session) {
     /**
      * @param int $cmid
      */
-    public function require_edit($cmid) {
+    public function require_edit(int $cmid): void {
         $this->page->requires->js('/mod/jazzquiz/js/sortable.min.js');
         $this->page->requires->js_call_amd('mod_jazzquiz/edit', 'initialize', [$cmid]);
     }
@@ -420,7 +354,7 @@ public function require_edit($cmid) {
      * @param jazzquiz_session $session
      * @param array $slots
      */
-    public function require_review(jazzquiz_session $session, array $slots) {
+    public function require_review(jazzquiz_session $session, array $slots): void {
         $this->require_core($session);
         $count = count($session->jazzquiz->questions);
         $params = [$count, true, $slots];
diff --git a/classes/privacy/provider.php b/classes/privacy/provider.php
index 2a67ae0..bd67130 100644
--- a/classes/privacy/provider.php
+++ b/classes/privacy/provider.php
@@ -26,14 +26,15 @@
 
 namespace mod_jazzquiz\privacy;
 
+use context;
+use context_module;
 use core_privacy\local\metadata\collection;
 use core_privacy\local\request\approved_contextlist;
 use core_privacy\local\request\contextlist;
 use core_privacy\local\request\helper;
 use core_privacy\local\request\transform;
 use core_privacy\local\request\writer;
-
-defined('MOODLE_INTERNAL') || die();
+use stdClass;
 
 /**
  * Privacy Subsystem implementation for mod_jazzquiz.
@@ -51,11 +52,12 @@ class provider implements
     \core_privacy\local\request\plugin\provider {
 
     /**
-     * Returns meta data about this system.
-     * @param   collection $items The initialised collection to add metadata to.
-     * @return  collection  A listing of user data stored through this system.
+     * Returns metadata about this system.
+     *
+     * @param collection $items The initialised collection to add metadata to.
+     * @return collection A listing of user data stored through this system.
      */
-    public static function get_metadata(collection $items) : collection {
+    public static function get_metadata(collection $items): collection {
         // The table 'jazzquiz' stores a record for each JazzQuiz.
         // It does not contain user personal data, but data is returned from it for contextual requirements.
 
@@ -66,7 +68,7 @@ public static function get_metadata(collection $items) : collection {
             'responded' => 'privacy:metadata:jazzquiz_attempts:responded',
             'timestart' => 'privacy:metadata:jazzquiz_attempts:timestart',
             'timefinish' => 'privacy:metadata:jazzquiz_attempts:timefinish',
-            'timemodified' => 'privacy:metadata:jazzquiz_attempts:timemodified'
+            'timemodified' => 'privacy:metadata:jazzquiz_attempts:timemodified',
         ], 'privacy:metadata:jazzquiz_attempts');
 
         // The 'jazzquiz_merges' table is used to merge one question attempt into another in a JazzQuiz session.
@@ -92,10 +94,10 @@ public static function get_metadata(collection $items) : collection {
     /**
      * Get the list of contexts where the specified user has attempted a JazzQuiz.
      *
-     * @param   int $userid The user to search.
-     * @return  contextlist  $contextlist The contextlist containing the list of contexts used in this plugin.
+     * @param int $userid The user to search.
+     * @return contextlist  $contextlist The contextlist containing the list of contexts used in this plugin.
      */
-    public static function get_contexts_for_userid(int $userid) : contextlist {
+    public static function get_contexts_for_userid(int $userid): contextlist {
         $sql = 'SELECT cx.id
                   FROM {context} cx
                   JOIN {course_modules} cm
@@ -115,7 +117,7 @@ public static function get_contexts_for_userid(int $userid) : contextlist {
         $contextlist->add_from_sql($sql, [
             'contextlevel' => CONTEXT_MODULE,
             'modname' => 'jazzquiz',
-            'userid' => $userid
+            'userid' => $userid,
         ]);
         return $contextlist;
     }
@@ -123,16 +125,10 @@ public static function get_contexts_for_userid(int $userid) : contextlist {
     /**
      * Export all user data for the specified user, in the specified contexts.
      *
-     * @param   approved_contextlist $contextlist The approved contexts to export information for.
-     * @throws \coding_exception
-     * @throws \dml_exception
-     * @throws \moodle_exception
+     * @param approved_contextlist $contextlist The approved contexts to export information for.
      */
-    public static function export_user_data(approved_contextlist $contextlist) {
+    public static function export_user_data(approved_contextlist $contextlist): void {
         global $DB;
-        if (empty($contextlist)) {
-            return;
-        }
         $user = $contextlist->get_user();
         list($contextsql, $contextparams) = $DB->get_in_or_equal($contextlist->get_contextids(), SQL_PARAMS_NAMED);
         $sql = "SELECT cm.id AS cmid
@@ -161,7 +157,7 @@ public static function export_user_data(approved_contextlist $contextlist) {
         // Fetch the individual quizzes.
         $quizzes = $DB->get_recordset_sql($sql, $params);
         foreach ($quizzes as $quiz) {
-            $context = \context_module::instance($quiz->cmid);
+            $context = context_module::instance($quiz->cmid);
             $data = helper::get_context_data($context, $user);
             helper::export_context_files($context, $user);
             writer::with_context($context)->export_data([], $data);
@@ -170,7 +166,7 @@ public static function export_user_data(approved_contextlist $contextlist) {
         static::export_quiz_attempts($contextlist);
     }
 
-    protected static function export_quiz_attempts(approved_contextlist $contextlist) {
+    protected static function export_quiz_attempts(approved_contextlist $contextlist): void {
         global $DB;
         $userid = $contextlist->get_user()->id;
         $sql = "SELECT cx.id              AS contextid,
@@ -198,12 +194,12 @@ protected static function export_quiz_attempts(approved_contextlist $contextlist
         $params = [
             'contextlevel' => CONTEXT_MODULE,
             'userid' => $userid,
-            'modname' => 'jazzquiz'
+            'modname' => 'jazzquiz',
         ];
         $attempts = $DB->get_recordset_sql($sql, $params);
         foreach ($attempts as $attempt) {
             $options = new \question_display_options();
-            $options->context = \context_module::instance($attempt->cmid);
+            $options->context = context_module::instance($attempt->cmid);
             $attemptsubcontext = [$attempt->sessionname . ' ' . $attempt->sessionid . ' ' . $attempt->id];
             // This attempt was made by the user. They 'own' all data on it. Store the question usage data.
             \core_question\privacy\provider::export_question_usage(
@@ -212,10 +208,10 @@ protected static function export_quiz_attempts(approved_contextlist $contextlist
                 $attemptsubcontext,
                 $attempt->qubaid,
                 $options,
-                true
+                true,
             );
             // Store the quiz attempt data.
-            $data = new \stdClass();
+            $data = new stdClass();
             $data->responded = $attempt->responded;
             $data->timestart = transform::datetime($attempt->timestart);
             $data->timefinish = transform::datetime($attempt->timefinish);
@@ -228,9 +224,9 @@ protected static function export_quiz_attempts(approved_contextlist $contextlist
     /**
      * Delete all data for all users in the specified context.
      *
-     * @param   \context $context The specific context to delete data for.
+     * @param context $context The specific context to delete data for.
      */
-    public static function delete_data_for_all_users_in_context(\context $context) {
+    public static function delete_data_for_all_users_in_context(context $context): void {
         global $DB;
         if ($context->contextlevel != CONTEXT_MODULE) {
             return;
@@ -249,9 +245,9 @@ public static function delete_data_for_all_users_in_context(\context $context) {
     /**
      * Delete all user data for the specified user, in the specified contexts.
      *
-     * @param   approved_contextlist $contextlist The approved contexts and user information to delete information for.
+     * @param approved_contextlist $contextlist Approved contexts and user information to delete information for.
      */
-    public static function delete_data_for_user(approved_contextlist $contextlist) {
+    public static function delete_data_for_user(approved_contextlist $contextlist): void {
         global $DB;
         if (empty($contextlist->count())) {
             return;
diff --git a/db/access.php b/db/access.php
index 4a32cf9..51ecbc0 100755
--- a/db/access.php
+++ b/db/access.php
@@ -51,57 +51,56 @@
     // Can start a quiz and move on to the next question.
     // NB: must have 'attempt' as well to be able to see the questions.
     'mod/jazzquiz:control' => [
-        'captype'      => 'write',
+        'captype' => 'write',
         'contextlevel' => CONTEXT_MODULE,
-        'legacy'       => [
-            'teacher'        => CAP_ALLOW,
+        'legacy' => [
+            'teacher' => CAP_ALLOW,
             'editingteacher' => CAP_ALLOW,
-            'manager'        => CAP_ALLOW
-        ]
+            'manager' => CAP_ALLOW,
+        ],
     ],
 
     // Can try to answer the quiz.
     'mod/jazzquiz:attempt' => [
-        'captype'      => 'write',
+        'captype' => 'write',
         'contextlevel' => CONTEXT_MODULE,
-        'legacy'       => [
-            'student'        => CAP_ALLOW,
-            'teacher'        => CAP_ALLOW,
+        'legacy' => [
+            'student' => CAP_ALLOW,
+            'teacher' => CAP_ALLOW,
             'editingteacher' => CAP_ALLOW,
-            'manager'        => CAP_ALLOW
-        ]
+            'manager' => CAP_ALLOW,
+        ],
     ],
 
     // Can see who gave what answer.
     'mod/jazzquiz:seeresponses' => [
-        'captype'      => 'read',
+        'captype' => 'read',
         'contextlevel' => CONTEXT_MODULE,
-        'legacy'       => [
-            'teacher'        => CAP_ALLOW,
+        'legacy' => [
+            'teacher' => CAP_ALLOW,
             'editingteacher' => CAP_ALLOW,
-            'manager'        => CAP_ALLOW
-        ]
+            'manager' => CAP_ALLOW,
+        ],
     ],
 
     // Can add / delete / update questions.
     'mod/jazzquiz:editquestions' => [
-        'captype'      => 'write',
+        'captype' => 'write',
         'contextlevel' => CONTEXT_MODULE,
-        'legacy'       => [
+        'legacy' => [
             'editingteacher' => CAP_ALLOW,
-            'manager'        => CAP_ALLOW
-        ]
+            'manager' => CAP_ALLOW,
+        ],
     ],
 
     // Can add an instance of this module to a course.
     'mod/jazzquiz:addinstance' => [
-        'captype'      => 'write',
+        'captype' => 'write',
         'contextlevel' => CONTEXT_COURSE,
-        'legacy'       => [
+        'legacy' => [
             'editingteacher' => CAP_ALLOW,
-            'coursecreator'  => CAP_ALLOW,
-            'manager'        => CAP_ALLOW
-        ]
+            'coursecreator' => CAP_ALLOW,
+            'manager' => CAP_ALLOW,
+        ],
     ],
 ];
-
diff --git a/db/upgrade.php b/db/upgrade.php
index 4b1d59f..3b7adde 100755
--- a/db/upgrade.php
+++ b/db/upgrade.php
@@ -14,9 +14,12 @@
 // 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();
-
-function xmldb_jazzquiz_upgrade($oldversion) {
+/**
+ * The upgrade script for JazzQuiz.
+ *
+ * @param int $oldversion
+ */
+function xmldb_jazzquiz_upgrade(int $oldversion): bool {
     global $DB;
     $dbman = $DB->get_manager();
     if ($oldversion < 2019061911) {
diff --git a/edit.php b/edit.php
index 17475cd..0257896 100755
--- a/edit.php
+++ b/edit.php
@@ -26,6 +26,10 @@
 
 namespace mod_jazzquiz;
 
+use core_question\local\bank\question_edit_contexts;
+use mod_jazzquiz\bank\add_questions_bank_view;
+use moodle_url;
+
 require_once('../../config.php');
 require_once($CFG->dirroot . '/mod/jazzquiz/lib.php');
 require_once($CFG->dirroot . '/mod/jazzquiz/locallib.php');
@@ -35,71 +39,39 @@
 
 /**
  * Check if this JazzQuiz has an open session.
+ *
  * @param int $jazzquizid
  * @return bool
- * @throws \dml_exception
  */
-function jazzquiz_session_open($jazzquizid) {
+function jazzquiz_session_open(int $jazzquizid): bool {
     global $DB;
     $sessions = $DB->get_records('jazzquiz_sessions', [
         'jazzquizid' => $jazzquizid,
-        'sessionopen' => 1
+        'sessionopen' => 1,
     ]);
     return count($sessions) > 0;
 }
 
 /**
- * Gets the question bank view based on the options passed in at the page setup.
- * @param \core_question\local\bank\question_edit_contexts $contexts
+ * Outputs the list of questions using the renderer for jazzquiz.
+ *
+ * @param question_edit_contexts $contexts
  * @param jazzquiz $jazzquiz
- * @param \moodle_url $url
+ * @param moodle_url $url
  * @param array $pagevars
- * @return string
- * @throws \coding_exception
  */
-function get_qbank_view(
-    \core_question\local\bank\question_edit_contexts $contexts,
-    jazzquiz $jazzquiz, \moodle_url $url, array $pagevars) {
-
-    $qperpage = optional_param('qperpage', 10, PARAM_INT);
-    $qpage = optional_param('qpage', 0, PARAM_INT);
-    $newpagevars = [
-        'qpage' => $qpage,
-        'qperpage' => $qperpage,
-        'cat' => $pagevars['cat'],
-        'recurse' => $pagevars['recurse'],
-        'showhidden' => $pagevars['showhidden'],
-        'qbshowtext' => $pagevars['qbshowtext']
-    ];
-    // Capture question bank display in buffer to have the renderer render output.
+function list_questions(question_edit_contexts $contexts, jazzquiz $jazzquiz, moodle_url $url, array $pagevars): void {
     ob_start();
-    $questionbank = new bank\jazzquiz_question_bank_view($contexts, $url, $jazzquiz->course, $jazzquiz->cm);
-    $questionbank->display($newpagevars, 'editq');
-    return ob_get_clean();
-}
-
-/**
- * Echos the list of questions using the renderer for jazzquiz.
- * @param \core_question\local\bank\question_edit_contexts $contexts
- * @param jazzquiz $jazzquiz
- * @param \moodle_url $url
- * @param array $pagevars
- * @throws \coding_exception
- * @throws \moodle_exception
- */
-function list_questions(
-    \core_question\local\bank\question_edit_contexts $contexts,
-    jazzquiz $jazzquiz, \moodle_url $url, array $pagevars) {
-
-    $qbankview = get_qbank_view($contexts, $jazzquiz, $url, $pagevars);
+    $questionbank = new add_questions_bank_view($contexts, $url, $jazzquiz->course, $jazzquiz->cm, $pagevars);
+    $questionbank->display();
+    $qbankview = ob_get_clean();
     $jazzquiz->renderer->list_questions($jazzquiz, $jazzquiz->questions, $qbankview, $url);
 }
 
 /**
  * @param jazzquiz $jazzquiz
- * @throws \coding_exception
  */
-function jazzquiz_edit_order(jazzquiz $jazzquiz) {
+function jazzquiz_edit_order(jazzquiz $jazzquiz): void {
     $order = required_param('order', PARAM_RAW);
     $order = json_decode($order);
     $jazzquiz->set_question_order($order);
@@ -107,11 +79,9 @@ function jazzquiz_edit_order(jazzquiz $jazzquiz) {
 
 /**
  * @param jazzquiz $jazzquiz
- * @param \moodle_url $url
- * @throws \coding_exception
- * @throws \moodle_exception
+ * @param moodle_url $url
  */
-function jazzquiz_edit_add_question(jazzquiz $jazzquiz, \moodle_url $url) {
+function jazzquiz_edit_add_question(jazzquiz $jazzquiz, moodle_url $url): void {
     $questionids = required_param('questionids', PARAM_TEXT);
     $questionids = explode(',', $questionids);
     foreach ($questionids as $questionid) {
@@ -124,25 +94,19 @@ function jazzquiz_edit_add_question(jazzquiz $jazzquiz, \moodle_url $url) {
 
 /**
  * @param jazzquiz $jazzquiz
- * @throws \coding_exception
  */
-function jazzquiz_edit_edit_question(jazzquiz $jazzquiz) {
+function jazzquiz_edit_edit_question(jazzquiz $jazzquiz): void {
     $questionid = required_param('questionid', PARAM_INT);
     $jazzquiz->edit_question($questionid);
 }
 
 /**
  * @param jazzquiz $jazzquiz
- * @param \core_question\local\bank\question_edit_contexts $contexts
- * @param \moodle_url $url
- * @param $pagevars
- * @throws \coding_exception
- * @throws \moodle_exception
+ * @param question_edit_contexts $contexts
+ * @param moodle_url $url
+ * @param array $pagevars
  */
-function jazzquiz_edit_qlist(
-    jazzquiz $jazzquiz, \core_question\local\bank\question_edit_contexts $contexts,
-    \moodle_url $url, array $pagevars) {
-
+function jazzquiz_edit_qlist(jazzquiz $jazzquiz, question_edit_contexts $contexts, moodle_url $url, array $pagevars): void {
     $jazzquiz->renderer->header($jazzquiz, 'edit');
     list_questions($contexts, $jazzquiz, $url, $pagevars);
     $jazzquiz->renderer->footer();
@@ -151,7 +115,7 @@ function jazzquiz_edit_qlist(
 /**
  * View edit page.
  */
-function jazzquiz_edit() {
+function jazzquiz_edit(): void {
     global $PAGE, $COURSE;
     $action = optional_param('action', 'listquestions', PARAM_ALPHA);
 
diff --git a/index.php b/index.php
index f73473e..f4754f7 100755
--- a/index.php
+++ b/index.php
@@ -26,11 +26,8 @@
 require_once('../../config.php');
 require_once('lib.php');
 
-$id = required_param('id', PARAM_INT); // Course ID.
-$course = $DB->get_record('course', ['id' => $id]);
-if (!$course) {
-    error('Course ID is incorrect');
-}
+$courseid = required_param('id', PARAM_INT);
+$course = $DB->get_record('course', ['id' => $courseid], '*', MUST_EXIST);
 
 $PAGE->set_url(new moodle_url('/mod/jazzquiz/index.php', ['id' => $course->id]));
 require_course_login($course);
@@ -72,9 +69,7 @@
 }
 
 foreach ($jazzquizzes as $jazzquiz) {
-    $url = new moodle_url('/mod/jazzquiz/view.php', [
-        'cmid' => $jazzquiz->coursemodule
-    ]);
+    $url = new moodle_url('/mod/jazzquiz/view.php', ['cmid' => $jazzquiz->coursemodule]);
     if (!$jazzquiz->visible) {
         // Show dimmed if the mod is hidden.
         $link = '<a class="dimmed" href="' . $url . '">' . $jazzquiz->name . '</a>';
@@ -91,4 +86,3 @@
 
 echo html_writer::table($table);
 echo $OUTPUT->footer();
-
diff --git a/lang/en/jazzquiz.php b/lang/en/jazzquiz.php
index 0c0f145..777a001 100755
--- a/lang/en/jazzquiz.php
+++ b/lang/en/jazzquiz.php
@@ -177,8 +177,7 @@
 
 // Instructions.
 $string['instructions_for_student'] = '<p>Please wait for the instructor to start the quiz.</p>';
-$string['instructions_for_instructor'] = '
-    <h3>Please make sure to read the instructions:</h3>
+$string['instructions_for_instructor'] = '<h3>Please make sure to read the instructions:</h3>
     <p>There are hotkeys available, which can be used when an input field is not focused.</p>
     <table>
         <tr>
diff --git a/lib.php b/lib.php
index 75f85bb..34a2129 100755
--- a/lib.php
+++ b/lib.php
@@ -23,8 +23,6 @@
  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 
-defined('MOODLE_INTERNAL') || die();
-
 /**
  * Given an object containing all the necessary data,
  * (defined by the form in mod.html) this function
@@ -35,7 +33,7 @@
  * @return int The id of the newly inserted jazzquiz record
  * @throws dml_exception
  */
-function jazzquiz_add_instance(\stdClass $jazzquiz) {
+function jazzquiz_add_instance(\stdClass $jazzquiz): int {
     global $DB;
     $jazzquiz->timemodified = time();
     $jazzquiz->timecreated = time();
@@ -52,7 +50,7 @@ function jazzquiz_add_instance(\stdClass $jazzquiz) {
  * @return boolean Success/Fail
  * @throws dml_exception
  */
-function jazzquiz_update_instance(\stdClass $jazzquiz) {
+function jazzquiz_update_instance(\stdClass $jazzquiz): bool {
     global $DB;
     $jazzquiz->timemodified = time();
     $jazzquiz->id = $jazzquiz->instance;
@@ -67,27 +65,21 @@ function jazzquiz_update_instance(\stdClass $jazzquiz) {
  * @param int $id Id of the module instance
  * @return boolean Success/Failure
  **/
-function jazzquiz_delete_instance($id) {
+function jazzquiz_delete_instance($id): bool {
     global $DB, $CFG;
 
     require_once($CFG->dirroot . '/mod/jazzquiz/locallib.php');
     require_once($CFG->libdir . '/questionlib.php');
     require_once($CFG->dirroot . '/question/editlib.php');
 
-    try {
-        $jazzquiz = $DB->get_record('jazzquiz', ['id' => $id], '*', MUST_EXIST);
-        // Go through each session and then delete them (also deletes all attempts for them).
-        $sessions = $DB->get_records('jazzquiz_sessions', ['jazzquizid' => $jazzquiz->id]);
-        foreach ($sessions as $session) {
-            \mod_jazzquiz\jazzquiz_session::delete($session->id);
-        }
-        // Delete all questions for this quiz.
-        $DB->delete_records('jazzquiz_questions', ['jazzquizid' => $jazzquiz->id]);
-        // Finally delete the jazzquiz object.
-        $DB->delete_records('jazzquiz', ['id' => $jazzquiz->id]);
-    } catch (Exception $e) {
-        return false;
+    $jazzquiz = $DB->get_record('jazzquiz', ['id' => $id], '*', MUST_EXIST);
+    // Go through each session and then delete them (also deletes all attempts for them).
+    $sessions = $DB->get_records('jazzquiz_sessions', ['jazzquizid' => $jazzquiz->id]);
+    foreach ($sessions as $session) {
+        \mod_jazzquiz\jazzquiz_session::delete($session->id);
     }
+    $DB->delete_records('jazzquiz_questions', ['jazzquizid' => $jazzquiz->id]);
+    $DB->delete_records('jazzquiz', ['id' => $jazzquiz->id]);
     return true;
 }
 
@@ -99,7 +91,7 @@ function jazzquiz_delete_instance($id) {
  * @uses $CFG
  * @return boolean
  **/
-function jazzquiz_cron() {
+function jazzquiz_cron(): bool {
     return true;
 }
 
@@ -110,7 +102,7 @@ function jazzquiz_cron() {
  * @param navigation_node $jazzquiznode
  * @return void
  */
-function jazzquiz_extend_settings_navigation($settings, $jazzquiznode) {
+function jazzquiz_extend_settings_navigation($settings, $jazzquiznode): void {
     global $PAGE, $CFG;
 
     // Require {@link questionlib.php}
@@ -132,7 +124,7 @@ function jazzquiz_extend_settings_navigation($settings, $jazzquiznode) {
  * @throws coding_exception
  * @throws dml_exception
  */
-function jazzquiz_pluginfile($course, $cm, $context, $filearea, $args, $forcedownload, $options = []) {
+function jazzquiz_pluginfile($course, $cm, $context, $filearea, $args, $forcedownload, $options = []): bool {
     global $DB;
     if ($context->contextlevel != CONTEXT_MODULE) {
         return false;
@@ -149,7 +141,7 @@ function jazzquiz_pluginfile($course, $cm, $context, $filearea, $args, $forcedow
     }
     $question = $DB->get_record('jazzquiz_question', [
         'id' => $questionid,
-        'quizid' => $cm->instance
+        'quizid' => $cm->instance,
     ]);
     if (!$question) {
         return false;
@@ -157,7 +149,8 @@ function jazzquiz_pluginfile($course, $cm, $context, $filearea, $args, $forcedow
     $fs = get_file_storage();
     $relative = implode('/', $args);
     $fullpath = "/$context->id/mod_jazzquiz/$filearea/$questionid/$relative";
-    if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
+    $file = $fs->get_file_by_hash(sha1($fullpath));
+    if (!$file || $file->is_directory()) {
         return false;
     }
     send_stored_file($file);
@@ -181,11 +174,12 @@ function jazzquiz_pluginfile($course, $cm, $context, $filearea, $args, $forcedow
  * @param array $options additional options affecting the file serving
  */
 function mod_jazzquiz_question_pluginfile($course, $context, $component, $filearea, $qubaid, $slot,
-                                          $args, $forcedownload, $options = []) {
+                                          $args, $forcedownload, $options = []): void {
     $fs = get_file_storage();
     $relative = implode('/', $args);
     $full = "/$context->id/$component/$filearea/$relative";
-    if (!$file = $fs->get_file_by_hash(sha1($full)) or $file->is_directory()) {
+    $file = $fs->get_file_by_hash(sha1($full));
+    if (!$file || $file->is_directory()) {
         send_file_not_found();
     }
     send_stored_file($file, 0, 0, $forcedownload, $options);
@@ -196,7 +190,7 @@ function mod_jazzquiz_question_pluginfile($course, $context, $component, $filear
  * @param string $feature
  * @return bool
  */
-function jazzquiz_supports(string $feature) : bool {
+function jazzquiz_supports(string $feature): bool {
     switch ($feature) {
         case FEATURE_MOD_INTRO:
         case FEATURE_BACKUP_MOODLE2:
diff --git a/locallib.php b/locallib.php
index 5913336..388177f 100755
--- a/locallib.php
+++ b/locallib.php
@@ -25,18 +25,14 @@
 
 use mod_jazzquiz\jazzquiz;
 
-defined('MOODLE_INTERNAL') || die();
-
 /**
  * @param jazzquiz $jazzquiz
  * @param int $id
  * @param array $row
  * @param string $capability
  * @param string $name
- * @throws coding_exception
- * @throws moodle_exception
  */
-function jazzquiz_view_tab(jazzquiz $jazzquiz, int $id, array &$row, string $capability, string $name) {
+function jazzquiz_view_tab(jazzquiz $jazzquiz, int $id, array &$row, string $capability, string $name): void {
     if (has_capability($capability, $jazzquiz->context)) {
         $url = new moodle_url("/mod/jazzquiz/$name.php", ['id' => $id]);
         $row[] = new tabobject($name, $url, get_string($name, 'jazzquiz'));
@@ -45,13 +41,12 @@ function jazzquiz_view_tab(jazzquiz $jazzquiz, int $id, array &$row, string $cap
 
 /**
  * Prints tabs for instructor.
+ *
  * @param jazzquiz $jazzquiz
  * @param string $tab
  * @return string HTML string of the tabs
- * @throws coding_exception
- * @throws moodle_exception
  */
-function jazzquiz_view_tabs(jazzquiz $jazzquiz, string $tab) : string {
+function jazzquiz_view_tabs(jazzquiz $jazzquiz, string $tab): string {
     $tabs = [];
     $row = [];
     $inactive = [];
diff --git a/reports.php b/reports.php
index 79e25a2..54fa7cb 100755
--- a/reports.php
+++ b/reports.php
@@ -28,6 +28,8 @@
 
 namespace mod_jazzquiz;
 
+use moodle_url;
+
 require_once("../../config.php");
 require_once($CFG->libdir . '/questionlib.php');
 require_once($CFG->dirroot . '/mod/jazzquiz/locallib.php');
@@ -39,19 +41,14 @@
 
 /**
  * @param jazzquiz $jazzquiz
- * @param \moodle_url $url
+ * @param moodle_url $url
  * @param int $sessionid
- * @throws \coding_exception
- * @throws \dml_exception
- * @throws \moodle_exception
  */
-function jazzquiz_view_session_report(jazzquiz $jazzquiz, \moodle_url $url, int $sessionid) {
+function jazzquiz_view_session_report(jazzquiz $jazzquiz, moodle_url $url, int $sessionid): void {
+    global $DB;
     if ($sessionid === 0) {
         // If no session id is specified, we try to load the first one.
-        global $DB;
-        $sessions = $DB->get_records('jazzquiz_sessions', [
-            'jazzquizid' => $jazzquiz->data->id
-        ]);
+        $sessions = $DB->get_records('jazzquiz_sessions', ['jazzquizid' => $jazzquiz->data->id]);
         if (count($sessions) === 0) {
             echo get_string('no_sessions_exist', 'jazzquiz');
             return;
@@ -67,9 +64,8 @@ function jazzquiz_view_session_report(jazzquiz $jazzquiz, \moodle_url $url, int
 
 /**
  * @param jazzquiz $jazzquiz
- * @throws \coding_exception
  */
-function jazzquiz_export_session_report(jazzquiz $jazzquiz) {
+function jazzquiz_export_session_report(jazzquiz $jazzquiz): void {
     $what = required_param('what', PARAM_ALPHANUM);
     $sessionid = required_param('sessionid', PARAM_INT);
     $session = new jazzquiz_session($jazzquiz, $sessionid);
@@ -96,7 +92,7 @@ function jazzquiz_export_session_report(jazzquiz $jazzquiz) {
     }
 }
 
-function jazzquiz_delete_session_report(int $sessionid) {
+function jazzquiz_delete_session_report(int $sessionid): void {
     if ($sessionid !== 0) {
         jazzquiz_session::delete($sessionid);
     }
@@ -105,7 +101,7 @@ function jazzquiz_delete_session_report(int $sessionid) {
 /**
  * Entry point for viewing reports.
  */
-function jazzquiz_reports() {
+function jazzquiz_reports(): void {
     global $PAGE;
     $cmid = optional_param('id', false, PARAM_INT);
     if (!$cmid) {
@@ -118,7 +114,7 @@ function jazzquiz_reports() {
     require_capability('mod/jazzquiz:seeresponses', $jazzquiz->context);
     $action = optional_param('action', '', PARAM_ALPHANUM);
 
-    $url = new \moodle_url('/mod/jazzquiz/reports.php');
+    $url = new moodle_url('/mod/jazzquiz/reports.php');
     $url->param('id', $cmid);
     $url->param('quizid', $jazzquiz->data->id);
     $url->param('action', $action);
@@ -136,7 +132,7 @@ function jazzquiz_reports() {
     if (!$isdownload) {
         $jazzquiz->renderer->header($jazzquiz, 'reports');
     }
-        $sessionid = optional_param('sessionid', 0, PARAM_INT);
+    $sessionid = optional_param('sessionid', 0, PARAM_INT);
     switch ($action) {
         case 'view':
             jazzquiz_view_session_report($jazzquiz, $url, $sessionid);
diff --git a/styles.css b/styles.css
index ce2d008..d09dd4a 100755
--- a/styles.css
+++ b/styles.css
@@ -5,23 +5,6 @@
     padding: 20px;
 }
 
-.jazzquiz-box .row {
-    margin: 5px;
-}
-
-.jazzquiz-box .inline-block {
-    display: inline-block;
-}
-
-.jazzquiz-box .span6 {
-    vertical-align: top;
-    width: 49.5%;
-}
-
-.jazzquiz-box .row .span6 {
-    padding: 5px;
-}
-
 .jazzquiz-save-question {
     height: 30px;
 }
@@ -345,44 +328,27 @@
     margin-left: 16px;
 }
 
-.jazzquiz-box .questionlist .dragquestion {
-    width: 10%;
+.dragquestion {
     cursor: move;
 }
 
-.jazzquiz-box .questionlist .icon {
-    vertical-align: middle;
-    height: auto;
-}
-
-.jazzquiz-box .questionlist .name {
-    width: calc(100% - 256px);
-    vertical-align: middle;
-}
-
 .jazzquiz-box .questionlist .name p {
     margin: 0;
 }
 
-.jazzquiz-box .questionlist .controls {
-    width: 100%;
-    vertical-align: middle;
+.jazzquiz-box .questionlist {
 }
 
 .jazzquiz-box .questionlist li {
-    min-height: 30px;
     margin: 4px;
     padding: 10px;
     border: 1px solid #ddd;
     background: #eee;
 }
 
-.jazzquiz-box .questionlist li div {
-    display: inline-block;
-}
-
-.jazzquiz-box .questionlist li:hover {
-    background: #ddd;
+.jazzquiz-box .questionlist .controls {
+    display: grid;
+    grid-template-columns: 32px 32px auto 32px 32px 32px 32px;
 }
 
 .jazzquiz-box .questionlist li a {
diff --git a/templates/continue_session.mustache b/templates/continue_session.mustache
index ff98e84..437f2e4 100755
--- a/templates/continue_session.mustache
+++ b/templates/continue_session.mustache
@@ -1,15 +1,32 @@
 {{!
-    @template continue_session
+    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/>.
+}}
+{{!
+    @template mod_jazzquiz/continue_session
+
+    Link to continue session.
 
     Example context (json):
     {
-        "str": "Continue session...",
-        "path": "https://example.com/"
+        "path": "/mod/jazzquiz/view.php?id=1&quizid=1&action=quizstart"
     }
 }}
 <div class="jazzquiz-box">
-    <p>{{# str }} instructor_sessions_going, jazzquiz {{/ str }}</p>
+    <p>{{#str}}instructor_sessions_going, jazzquiz{{/str}}</p>
     <p>
-        <a href="{{ path }}" class="btn btn-secondary">{{# str }} goto_session, jazzquiz {{/ str }}</a>
+        <a href="{{path}}" class="btn btn-secondary">{{#str}}goto_session, jazzquiz{{/str}}</a>
     </p>
-</div>
\ No newline at end of file
+</div>
diff --git a/templates/edit_question_list.mustache b/templates/edit_question_list.mustache
index 3c6768d..a76d1d9 100755
--- a/templates/edit_question_list.mustache
+++ b/templates/edit_question_list.mustache
@@ -1,48 +1,84 @@
 {{!
-    @template edit_question_list
+    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/>.
 }}
+{{!
+    @template mod_jazzquiz/edit_question_list
+
+    Edit the questions used for a quiz.
+
+    Example context (json):
+    {
+        "questions": [
+            {
+                "id": 713,
+                "name": "Example question",
+                "first": true,
+                "last": false,
+                "slot": 1,
+                "editurl": "/mod/jazzquiz/edit.php?questionid=713&action=editquestion",
+                "icon": ""
+            },
+            {
+                "id": 509,
+                "name": "Another question",
+                "first": false,
+                "last": true,
+                "slot": 2,
+                "editurl": "/mod/jazzquiz/edit.php?questionid=509&action=editquestion",
+                "icon": ""
+            }
+        ],
+        "qbank": ""
+    }
+}}
+<div class="generalbox boxaligncenter jazzquiz-box jazzquiz-response-container">
+    <h2>{{#str}}questions, jazzquiz{{/str}}</h2>
+    <ol class="questionlist">
+    {{#questions}}
+        <li data-question-id="{{id}}">
+            <div class="controls">
+                <div class="dragquestion">{{#pix}}i/dragdrop, core{{/pix}}</div>
+                <div class="icon">{{{icon}}}</div>
+                <div class="name">
+                    <span class="filter_mathjaxloader_equation">{{{name}}}</span>
+                </div>
+                {{#first}}{{#pix}}spacer, core{{/pix}}{{/first}}
+                {{^first}}
+                    <a class="edit-question-action" data-action="up" data-question-id="{{id}}">
+                        {{#pix}}t/up, core, {{#str}}question_move_up, jazzquiz, {{slot}}{{/str}}{{/pix}}
+                    </a>
+                {{/first}}
+                {{#last}}{{#pix}}spacer, core{{/pix}}{{/last}}
+                {{^last}}
+                    <a class="edit-question-action" data-action="down" data-question-id="{{id}}">
+                        {{#pix}}t/down, core, {{#str}}question_move_down, jazzquiz, {{slot}}{{/str}}{{/pix}}
+                    </a>
+                {{/last}}
+                <a href="{{{editurl}}}">{{#pix}} t/edit, core, {{#str}}edit_question, jazzquiz{{/str}}{{/pix}}</a>
+                <a class="edit-question-action" data-action="delete" data-question-id="{{id}}">
+                    {{#pix}}t/delete, core, {{#str}}delete_question, jazzquiz, {{slot}}{{/str}}{{/pix}}
+                </a>
+            </div>
+        </li>
+    {{/questions}}
+    </ol>
+</div>
+
+<hr>
+
 <div class="generalbox boxaligncenter jazzquiz-box jazzquiz-response-container">
-    <div id="questionrow" class="row">
-        <div class="inline-block span6">
-            <h2>{{# str }} questions, jazzquiz {{/ str }}</h2>
-            <ol class="questionlist">
-                {{# questions }}
-                    <li data-question-id="{{ id }}">
-                        <div class="controls">
-                            <div class="dragquestion">
-                                {{# pix }} i/dragdrop, core {{/ pix }}
-                            </div>
-                            <div class="icon">
-                                {{{ icon }}}
-                            </div>
-                            <div class="name">
-                                <span class="filter_mathjaxloader_equation">
-                                    {{{ name }}}
-                                </span>
-                            </div>
-                            {{# first }}{{# pix }} spacer, core {{/ pix }}{{/ first }}
-                            {{^ first }}
-                                <a class="edit-question-action" data-action="up" data-question-id="{{ id }}">
-                                    {{# pix }} t/up, core, {{# str }} question_move_up, jazzquiz, {{ slot }} {{/ str }} {{/ pix }}
-                                </a>
-                            {{/ first }}
-                            {{# last }}{{# pix }} spacer, core {{/ pix }}{{/ last }}
-                            {{^ last }}
-                                <a class="edit-question-action" data-action="down" data-question-id="{{ id }}">
-                                    {{# pix }} t/down, core, {{# str }} question_move_down, jazzquiz, {{ slot }} {{/ str }} {{/ pix }}
-                                </a>
-                            {{/ last }}
-                            <a href="{{{ editurl }}}">{{# pix }} t/edit, core, {{# str }} edit_question, jazzquiz {{/ str }} {{/ pix }}</a>
-                            <a class="edit-question-action" data-action="delete" data-question-id="{{ id }}">
-                                {{# pix }} t/delete, core, {{# str }} delete_question, jazzquiz, {{ slot }} {{/ str }} {{/ pix }}
-                            </a>
-                        </div>
-                    </li>
-                {{/ questions  }}
-            </ol>
-        </div>
-        <div class="inline-block span6">
-            {{{ qbank }}}
-        </div>
-    </div>
-</div>
\ No newline at end of file
+    {{{qbank}}}
+</div>
diff --git a/templates/guests_not_allowed.mustache b/templates/guests_not_allowed.mustache
index 0110232..de93c38 100644
--- a/templates/guests_not_allowed.mustache
+++ b/templates/guests_not_allowed.mustache
@@ -1,8 +1,30 @@
 {{!
-    @template guests_not_allowed
+    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/>.
+}}
+{{!
+    @template mod_jazzquiz/guests_not_allowed
+
+    Guests are not allowed to access this quiz.
+
+    Example context (json):
+    {
+    }
 }}
 <div class="jazzquiz-box">
-    <p>{{# str }} guest_login, jazzquiz {{/ str }}</p>
-    <p>{{# str }} no_guests, jazzquiz {{/ str }}</p>
-    <p>{{# str }} ask_teacher, jazzquiz {{/ str }}</p>
+    <p>{{#str}}guest_login, jazzquiz{{/str}}</p>
+    <p>{{#str}}no_guests, jazzquiz{{/str}}</p>
+    <p>{{#str}}ask_teacher, jazzquiz{{/str}}</p>
 </div>
diff --git a/templates/join_session.mustache b/templates/join_session.mustache
index 1d747c7..5023fd8 100755
--- a/templates/join_session.mustache
+++ b/templates/join_session.mustache
@@ -1,14 +1,36 @@
 {{!
-    @template join_session
+    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/>.
+}}
+{{!
+    @template mod_jazzquiz/join_session
+
+    Show button to enter an ongoing JazzQuiz session.
+
+    Example context (json):
+    {
+        "name": "Example questions",
+        "anonymity_info": "Guests are allowed",
+        "started": true,
+        "form": ""
+    }
 }}
 <div class="jazzquiz-box">
-    <p>{{# str }} join_quiz_instructions, jazzquiz {{/ str }}</p>
-    <p>
-        <b>{{# str }} session, jazzquiz {{/ str }}:</b> {{ name }}
-    </p>
-    <p>{{ anonymity_info }}</p>
-    {{# started }}
-    <p>{{# str }} attempt_started, jazzquiz {{/ str }}</p>
-    {{/ started }}
-    {{{ form }}}
-</div>
\ No newline at end of file
+    <p>{{#str}}join_quiz_instructions, jazzquiz{{/str}}</p>
+    <p><b>{{#str}}session, jazzquiz{{/str}}:</b> {{name}}</p>
+    <p>{{anonymity_info}}</p>
+    {{#started}}<p>{{#str}}attempt_started, jazzquiz{{/str}}</p>{{/started}}
+    {{{form}}}
+</div>
diff --git a/templates/no_session.mustache b/templates/no_session.mustache
index 3bb497f..da808c4 100755
--- a/templates/no_session.mustache
+++ b/templates/no_session.mustache
@@ -1,9 +1,32 @@
 {{!
-    @template no_session
+    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/>.
+}}
+{{!
+    @template mod_jazzquiz/no_session
+
+    There is no session ongoing. Display a button to refresh the page to check again.
+
+    Example context (json):
+    {
+        "reload": "/mod/jazzquiz/view.php?id=1"
+    }
 }}
 <div class="jazzquiz-box">
-    <p>{{# str }} quiz_not_running, jazzquiz {{/ str }}</p>
+    <p>{{#str}}quiz_not_running, jazzquiz{{/str}}</p>
     <p>
-        <a href="{{ reload }}" class="btn btn-secondary">{{# str }} reload {{/ str }}</a>
+        <a href="{{reload}}" class="btn btn-secondary">{{#str}}reload{{/str}}</a>
     </p>
-</div>
\ No newline at end of file
+</div>
diff --git a/templates/question.mustache b/templates/question.mustache
index 9a16d63..941393b 100755
--- a/templates/question.mustache
+++ b/templates/question.mustache
@@ -1,16 +1,41 @@
 {{!
-    @template question
+    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/>.
 }}
-<div class="jazzquiz-box {{# instructor }}instructor{{/ instructor }}">
-    <form id="jazzquiz_question_form" action="" method="post" enctype="multipart/form-data" accept-charset="utf8" onsubmit="return false;">
-        <div class="jazzquiz-response-container">{{{ question }}}</div>
-        <input type="hidden" name="slot" value="{{ slot }}">
-        {{^ instructor }}
+{{!
+    @template mod_jazzquiz/question
+
+    Display attempt form for a question.
+
+    Example context (json):
+    {
+        "instructor": false,
+        "question": "",
+        "slot": 1
+    }
+}}
+<div class="jazzquiz-box {{#instructor}}instructor{{/instructor}}">
+    <form id="jazzquiz_question_form" action="" method="post" enctype="multipart/form-data" accept-charset="utf-8" onsubmit="return false;">
+        <div class="jazzquiz-response-container">{{{question}}}</div>
+        <input type="hidden" name="slot" value="{{slot}}">
+        {{^instructor}}
         <div class="save_row">
             <div class="jazzquiz-save-question">
-                <button class="btn btn-primary">Submit</button>
+                <button class="btn btn-primary">{{#str}}core, submit{{/str}}</button>
             </div>
         </div>
-        {{/ instructor }}
+        {{/instructor}}
     </form>
-</div>
\ No newline at end of file
+</div>
diff --git a/templates/quiz.mustache b/templates/quiz.mustache
index 2ff9728..e4a5af4 100755
--- a/templates/quiz.mustache
+++ b/templates/quiz.mustache
@@ -1,25 +1,57 @@
 {{!
-    @template quiz
+    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/>.
+}}
+{{!
+    @template mod_jazzquiz/quiz
+
+    Main wrapper for a JazzQuiz session.
+
+    Example context (json):
+    {
+        "instructor": true,
+        "buttons": [
+            {
+                "id": "improvise",
+                "icon": "edit",
+                "text": "Improvise"
+            }
+        ]
+    }
 }}
 <div id="jazzquiz">
-    {{# instructor }}
+    {{#instructor}}
     <div id="jazzquiz_controls_box" class="jazzquiz-box">
         <div id="jazzquiz_controls">
             <div class="quiz-list-buttons quiz-control-buttons hidden">
-                {{# buttons }}<button id="jazzquiz_control_{{ id }}" class="btn">
-                    <i class="fa fa-{{ icon }}"></i> {{ text }}
-                </button>{{/ buttons }}
+                {{#buttons}}
+                <button id="jazzquiz_control_{{id}}" class="btn">
+                    <i class="fa fa-{{ icon }}"></i> {{text}}
+                </button>
+                {{/buttons}}
                 <div style="clear:both;"></div>
             </div>
             <div id="jazzquiz_improvise_menu" class="start-question-menu"></div>
             <div id="jazzquiz_jump_menu" class="start-question-menu"></div>
             <div class="quiz-list-buttons">
                 <button id="jazzquiz_control_startquiz" class="btn">
-                    <i class="fa fa-start"></i> {{# str }} startquiz, jazzquiz {{/ str }}
+                    <i class="fa fa-start"></i> {{#str}}startquiz, jazzquiz{{/str}}
                 </button>
                 <h4 class="inline"></h4>
                 <button id="jazzquiz_control_exit" class="btn">
-                    <i class="fa fa-close"></i> {{# str }} exit, jazzquiz {{/ str }}
+                    <i class="fa fa-close"></i> {{#str}}exit, jazzquiz{{/str}}
                 </button>
             </div>
             <div id="jazzquiz_control_separator"></div>
@@ -37,18 +69,18 @@
         <div id="jazzquiz_question_timer" class="jazzquiz-box hidden"></div>
         <div id="jazzquiz_response_info_container" class="jazzquiz-box hidden"></div>
     </div>
-    {{/ instructor }}
-    {{^ instructor }}
+    {{/instructor}}
+    {{^instructor}}
     <div id="jazzquiz_question_timer" class="jazzquiz-box hidden"></div>
-    {{/ instructor }}
+    {{/instructor}}
     <div id="jazzquiz_info_container" class="jazzquiz-box hidden"></div>
     <div id="jazzquiz_question_box"></div>
-    {{# instructor }}
+    {{#instructor}}
     <div>
         <button id="jazzquiz_undo_merge" class="btn btn-primary hidden">
             <i class="fa fa-undo"></i>
         </button>
     </div>
     <div id="jazzquiz_responses_container" class="jazzquiz-response-container jazzquiz-box hidden"></div>
-    {{/ instructor }}
-</div>
\ No newline at end of file
+    {{/instructor}}
+</div>
diff --git a/templates/report.mustache b/templates/report.mustache
index 7b59063..7476df2 100755
--- a/templates/report.mustache
+++ b/templates/report.mustache
@@ -1,73 +1,154 @@
 {{!
-    @template report
+    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/>.
+}}
+{{!
+    @template mod_jazzquiz/report
+
+    Reports for JazzQuiz sessions.
+
+    Example context (json):
+    {
+        "select_session": [
+            "method": "get",
+            "action": "/mod/jazzquiz/reports.php",
+            "formid": "jazzquiz_select_session_form",
+            "id": "jazzquiz_select_session",
+            "name": "sessionid",
+            "options": [
+                {
+                    "name": "First session",
+                    "value": 1,
+                    "selected": true,
+                    "optgroup": false
+                }
+            ],
+            "params": [
+                {
+                    "name": "id",
+                    "value": 1
+                },
+                {
+                    "name": "action",
+                    "value": "view"
+                }
+            ]
+        ],
+        "session": {
+            "slots": [
+                {
+                    "num": 1,
+                    "name": "Example question",
+                    "type": "multichoice",
+                    "description": "Description for this question",
+                    "responses": [
+                        {
+                            "response": "42"
+                        },
+                        {
+                            "response": "I don't know"
+                        }
+                    ]
+                }
+            ],
+            "students": [
+                {
+                    "idnumber": 1,
+                    "name": "Student",
+                    "count": 1
+                },
+                {
+                    "name": "Guest",
+                    "count": 1
+                }
+            ],
+            "count_total": 2,
+            "count_answered": 2,
+            "cmid": 1,
+            "quizid": 1,
+            "id": 1
+        }
+    }
 }}
 <div class="jazzquiz-box">
-    {{# select_session }}
+    {{#select_session}}
     <div>
-        <h3>{{# str }} select_session, jazzquiz {{/ str }}</h3>
+        <h3>{{#str}}select_session, jazzquiz{{/str}}</h3>
         <br>
         <div class="inline-block">
-            {{> core/single_select }}
+            {{>core/single_select}}
         </div>
     </div>
-    {{/ select_session }}
-    {{# session }}
+    {{/select_session}}
+    {{#session}}
         <div id="report_overview_controls" class="jazzquiz-box">
             <button data-action="attendance" class="btn btn-primary">
-                {{# str }} attendance, jazzquiz {{/str}}
+                {{#str}}attendance, jazzquiz{{/str}}
             </button>
             <button data-action="responses" class="btn btn-primary">
-                {{# str }} responses, jazzquiz {{/str}}
+                {{#str}}responses, jazzquiz{{/str}}
             </button>
-            <a href="reports.php?id={{ cmid }}&quizid={{ quizid }}&sessionid={{ id }}&action=export&what=report&download=yes">
-                {{# str }} download_report, jazzquiz {{/str}}
+            <a href="reports.php?id={{cmid}}&quizid={{quizid}}&sessionid={{id}}&action=export&what=report&download=yes">
+                {{#str}}download_report, jazzquiz{{/str}}
             </a>
-            <a href="reports.php?id={{ cmid }}&quizid={{ quizid }}&sessionid={{ id }}&action=delete">
-                {{# str }} delete_report, jazzquiz {{/str}}
+            <a href="reports.php?id={{cmid}}&quizid={{quizid}}&sessionid={{id}}&action=delete">
+                {{#str}}delete_report, jazzquiz{{/str}}
             </a>
         </div>
         <div id="report_overview_responses" class="jazzquiz-response-container hidden">
-            {{# slots }}
+            {{#slots}}
                 <div class="jazzquiz-box">
                     <h2>
                         <span class="filter_mathjaxloader_equation">
-                                {{{ name }}}
+                                {{{name}}}
                         </span>
                     </h2>
                     <span class="filter_mathjaxloader_equation">
-                        {{{ description }}}
+                        {{{description}}}
                     </span>
-                    <table id="responses_wrapper_table_{{ num }}" class="jazzquiz-responses-overview"></table>
+                    <table id="responses_wrapper_table_{{num}}" class="jazzquiz-responses-overview"></table>
                     <br>
-                    <a href="reports.php?id={{ cmid }}&quizid={{ quizid }}&sessionid={{ id }}&slot={{ num }}&action=export&what=question&download=yes">
-                        {{# str }} download_responses, jazzquiz {{/ str }}
+                    <a href="reports.php?id={{cmid}}&quizid={{quizid}}&sessionid={{id}}&slot={{num}}&action=export&what=question&download=yes">
+                        {{#str}}download_responses, jazzquiz{{/str}}
                     </a>
                 </div>
-            {{/ slots }}
+            {{/slots}}
         </div>
         <div id="report_overview_responded" class="jazzquiz-box">
-            <h2>{{# str }} attendance_list, jazzquiz {{/str}}</h2>
+            <h2>{{#str}}attendance_list, jazzquiz{{/str}}</h2>
             <table>
                 <tr>
-                    <th>Student ID</th> 
-                    <th>{{# str }} student, jazzquiz {{/str}}</th>
-                    <th>{{# str }} responses, jazzquiz {{/ str }}</th>
+                    <th>Student ID</th>
+                    <th>{{#str}}student, jazzquiz{{/str}}</th>
+                    <th>{{#str}}responses, jazzquiz{{/str}}</th>
                 </tr>
-                {{# students }}
+                {{#students}}
                     <tr>
-                        <td>{{ idnumber }}</td>
-                        <td>{{ name }}</td>
-                        <td>{{# str }} a_responses, jazzquiz, {{ count }} {{/ str }}</td>
+                        <td>{{idnumber}}</td>
+                        <td>{{name}}</td>
+                        <td>{{#str}}a_responses, jazzquiz, {{count}}{{/str}}</td>
                     </tr>
-                {{/ students }}
+                {{/students}}
             </table>
             <br>
-            <p>{{# str }} a_students_joined_quiz, jazzquiz, {{ count_total }} {{/ str }}</p>
-            <p>{{# str }} a_students_answered, jazzquiz, {{ count_answered }} {{/ str }}</p>
+            <p>{{#str}}a_students_joined_quiz, jazzquiz, {{count_total}}{{/str}}</p>
+            <p>{{#str}}a_students_answered, jazzquiz, {{count_answered}}{{/str}}</p>
             <br>
-            <a href="reports.php?id={{ cmid }}&quizid={{ quizid }}&sessionid={{ id }}&action=export&what=attendance&download=yes">
-                {{# str }} download_attendance_list, jazzquiz {{/ str }}
+            <a href="reports.php?id={{cmid}}&quizid={{quizid}}&sessionid={{id}}&action=export&what=attendance&download=yes">
+                {{#str}}download_attendance_list, jazzquiz{{/str}}
             </a>
         </div>
-    {{/ session }}
+    {{/session}}
 </div>
diff --git a/templates/start_session.mustache b/templates/start_session.mustache
index 2f03678..2a992f2 100755
--- a/templates/start_session.mustache
+++ b/templates/start_session.mustache
@@ -1,8 +1,31 @@
 {{!
-    @template start_session
+    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/>.
+}}
+{{!
+    @template mod_jazzquiz/start_session
+
+    Show form to start a new session.
+
+    Example context (json):
+    {
+        "form": ""
+    }
 }}
 <div class="jazzquiz-box">
-    <p>{{# str }} teacher_start_instructions, jazzquiz {{/ str }}</p>
+    <p>{{#str}}teacher_start_instructions, jazzquiz{{/str}}</p>
     <br>
-    {{{ form }}}
-</div>
\ No newline at end of file
+    {{{form}}}
+</div>
diff --git a/view.php b/view.php
index a14822b..6f39778 100755
--- a/view.php
+++ b/view.php
@@ -25,7 +25,9 @@
  */
 
 namespace mod_jazzquiz;
-use Exception;
+
+use moodle_url;
+use required_capability_exception;
 
 require_once("../../config.php");
 require_once($CFG->dirroot . '/mod/jazzquiz/lib.php');
@@ -37,11 +39,10 @@
 
 /**
  * View the quiz page.
+ *
  * @param jazzquiz $jazzquiz
- * @throws \dml_exception
- * @throws \moodle_exception
  */
-function jazzquiz_view_start_quiz(jazzquiz $jazzquiz) {
+function jazzquiz_view_start_quiz(jazzquiz $jazzquiz): void {
     global $PAGE;
     // Set the quiz view page to the base layout for 1 column layout.
     $PAGE->set_pagelayout('base');
@@ -55,11 +56,11 @@ function jazzquiz_view_start_quiz(jazzquiz $jazzquiz) {
     $session->load_attempts();
     $session->initialize_attempt();
     if ($jazzquiz->is_instructor()) {
-        $session->attempt->data->status = jazzquiz_attempt::PREVIEW;
+        $session->myattempt->status = jazzquiz_attempt::PREVIEW;
     } else {
-        $session->attempt->data->status = jazzquiz_attempt::INPROGRESS;
+        $session->myattempt->status = jazzquiz_attempt::INPROGRESS;
     }
-    $session->attempt->save();
+    $session->myattempt->save();
 
     // Initialize JavaScript for the question engine.
     // TODO: Not certain if this is needed. Should be checked further.
@@ -73,35 +74,23 @@ function jazzquiz_view_start_quiz(jazzquiz $jazzquiz) {
 
 /**
  * View the "Continue session" or "Start session" form.
+ *
  * @param jazzquiz $jazzquiz
- * @throws \dml_exception
- * @throws \moodle_exception
  */
-function jazzquiz_view_default_instructor(jazzquiz $jazzquiz) {
-    global $PAGE, $DB;
+function jazzquiz_view_default_instructor(jazzquiz $jazzquiz): void {
+    global $PAGE;
     $startsessionform = new forms\view\start_session($PAGE->url, ['jazzquiz' => $jazzquiz]);
     $data = $startsessionform->get_data();
     if ($data) {
-        $sessions = $DB->get_records('jazzquiz_sessions', [
-            'jazzquizid' => $jazzquiz->data->id,
-            'sessionopen' => 1
-        ]);
-        // Only create session if not already open.
-        if (empty($sessions)) {
-            $allowguests = isset($data->allowguests) ? 1 : 0;
-            $sessionid = $jazzquiz->create_session($data->session_name, $data->anonymity, $allowguests);
-            if ($sessionid === false) {
-                return;
-            }
-        } else {
+        if ($jazzquiz->is_session_open()) {
             redirect($PAGE->url, 'A session is already open.', 0);
-            // Note: Redirect exits.
+        } else {
+            $jazzquiz->create_session($data->session_name, $data->anonymity, isset($data->allowguests));
         }
         // Redirect to the quiz start.
         $quizstarturl = clone($PAGE->url);
         $quizstarturl->param('action', 'quizstart');
         redirect($quizstarturl, null, 0);
-        // Note: Redirect exits.
     }
     $renderer = $jazzquiz->renderer;
     $renderer->header($jazzquiz, 'view');
@@ -115,10 +104,10 @@ function jazzquiz_view_default_instructor(jazzquiz $jazzquiz) {
 
 /**
  * View the "Join quiz" or "Quiz not running" form.
+ *
  * @param jazzquiz $jazzquiz
- * @throws \moodle_exception
  */
-function jazzquiz_view_default_student(jazzquiz $jazzquiz) {
+function jazzquiz_view_default_student(jazzquiz $jazzquiz): void {
     global $PAGE;
     $studentstartform = new forms\view\student_start_form($PAGE->url);
     $data = $studentstartform->get_data();
@@ -126,7 +115,6 @@ function jazzquiz_view_default_student(jazzquiz $jazzquiz) {
         $quizstarturl = clone($PAGE->url);
         $quizstarturl->param('action', 'quizstart');
         redirect($quizstarturl, null, 0);
-        // Note: Redirect exits.
     }
 
     /** @var output\renderer $renderer */
@@ -143,11 +131,10 @@ function jazzquiz_view_default_student(jazzquiz $jazzquiz) {
 
 /**
  * View appropriate form based on role and session state.
+ *
  * @param jazzquiz $jazzquiz
- * @throws \dml_exception
- * @throws \moodle_exception
  */
-function jazzquiz_view_default(jazzquiz $jazzquiz) {
+function jazzquiz_view_default(jazzquiz $jazzquiz): void {
     if ($jazzquiz->is_instructor()) {
         // Show "Start quiz" form.
         jazzquiz_view_default_instructor($jazzquiz);
@@ -157,18 +144,14 @@ function jazzquiz_view_default(jazzquiz $jazzquiz) {
     }
 }
 
-
 /**
  * Entry point for viewing a quiz.
  */
-function jazzquiz_view() {
+function jazzquiz_view(): void {
     global $PAGE;
-    $cmid = optional_param('id', false, PARAM_INT);
-    if (!$cmid) {
-        // Probably a login redirect that doesn't include any ID.
-        // Go back to the main Moodle page, because we have no info.
-        header('Location: /');
-        exit;
+    $cmid = optional_param('id', 0, PARAM_INT);
+    if ($cmid === 0) {
+        redirect(new moodle_url('/'));
     }
 
     $action = optional_param('action', '', PARAM_ALPHANUM);
@@ -177,14 +160,12 @@ function jazzquiz_view() {
     $iscapable = true;
 
     /*
-     * Checks that the user is authorised for he quiz.
-     * access or not.
+     * Checks that the user is authorised for the quiz access or not.
      * The require_capability() method checks this for students
      * and teacher, but it cannot handle the case where guest
-     * access is allowed.  Hence, if guests are allowed, no
-     * further check is made.
+     * access is allowed.  Hence, if guests are allowed, no further check is made.
      */
-    if (!$session || $session->data->allowguests != 1) {
+    if ($session === null || $session->data->allowguests != 1) {
         try {
             /*
              * require_capability() throws an exception if the user does not
@@ -192,7 +173,7 @@ function jazzquiz_view() {
              * or teacher is not enrolled on the course.
              */
             require_capability('mod/jazzquiz:attempt', $jazzquiz->context);
-        } catch (Exception $e) {
+        } catch (required_capability_exception) {
             // Indicates that the guest user is not allowed to access this session.
             $iscapable = false;
         }
@@ -202,10 +183,10 @@ function jazzquiz_view() {
     $PAGE->set_context($jazzquiz->context);
     $PAGE->set_cm($jazzquiz->cm);
     $modname = get_string('modulename', 'jazzquiz');
-    $quizname = format_string($jazzquiz->data->name, true);
+    $quizname = format_string($jazzquiz->data->name);
     $PAGE->set_title(strip_tags($jazzquiz->course->shortname . ': ' . $modname . ': ' . $quizname));
     $PAGE->set_heading($jazzquiz->course->fullname);
-    $url = new \moodle_url('/mod/jazzquiz/view.php');
+    $url = new moodle_url('/mod/jazzquiz/view.php');
     $url->param('id', $cmid);
     $url->param('quizid', $jazzquiz->data->id);
     $url->param('action', $action);