1<?php
2// This file is part of Moodle - http://moodle.org/
3//
4// Moodle is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8//
9// Moodle is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12// GNU General Public License for more details.
13//
14// You should have received a copy of the GNU General Public License
15// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
16
17/**
18 * This page displays a preview of a question
19 *
20 * The preview uses the option settings from the activity within which the question
21 * is previewed or the default settings if no activity is specified. The question session
22 * information is stored in the session as an array of subsequent states rather
23 * than in the database.
24 *
25 * @package    moodlecore
26 * @subpackage questionengine
27 * @copyright  Alex Smith {@link http://maths.york.ac.uk/serving_maths} and
28 *      numerous contributors.
29 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
30 */
31
32
33require_once(__DIR__ . '/../config.php');
34require_once($CFG->libdir . '/questionlib.php');
35require_once(__DIR__ . '/previewlib.php');
36
37/**
38 * The maximum number of variants previewable. If there are more variants than this for a question
39 * then we only allow the selection of the first x variants.
40 * @var integer
41 */
42define('QUESTION_PREVIEW_MAX_VARIANTS', 100);
43
44// Get and validate question id.
45$id = required_param('id', PARAM_INT);
46$question = question_bank::load_question($id);
47
48// Were we given a particular context to run the question in?
49// This affects things like filter settings, or forced theme or language.
50if ($cmid = optional_param('cmid', 0, PARAM_INT)) {
51    $cm = get_coursemodule_from_id(false, $cmid);
52    require_login($cm->course, false, $cm);
53    $context = context_module::instance($cmid);
54
55} else if ($courseid = optional_param('courseid', 0, PARAM_INT)) {
56    require_login($courseid);
57    $context = context_course::instance($courseid);
58
59} else {
60    require_login();
61    $category = $DB->get_record('question_categories',
62            array('id' => $question->category), '*', MUST_EXIST);
63    $context = context::instance_by_id($category->contextid);
64    $PAGE->set_context($context);
65    // Note that in the other cases, require_login will set the correct page context.
66}
67question_require_capability_on($question, 'use');
68$PAGE->set_pagelayout('popup');
69
70// Get and validate display options.
71$maxvariant = min($question->get_num_variants(), QUESTION_PREVIEW_MAX_VARIANTS);
72$options = new question_preview_options($question);
73$options->load_user_defaults();
74$options->set_from_request();
75$PAGE->set_url(question_preview_url($id, $options->behaviour, $options->maxmark,
76        $options, $options->variant, $context));
77
78// Get and validate existing preview, or start a new one.
79$previewid = optional_param('previewid', 0, PARAM_INT);
80
81if ($previewid) {
82    try {
83        $quba = question_engine::load_questions_usage_by_activity($previewid);
84
85    } catch (Exception $e) {
86        // This may not seem like the right error message to display, but
87        // actually from the user point of view, it makes sense.
88        print_error('submissionoutofsequencefriendlymessage', 'question',
89                question_preview_url($question->id, $options->behaviour,
90                $options->maxmark, $options, $options->variant, $context), null, $e);
91    }
92
93    if ($quba->get_owning_context()->instanceid != $USER->id) {
94        print_error('notyourpreview', 'question');
95    }
96
97    $slot = $quba->get_first_question_number();
98    $usedquestion = $quba->get_question($slot, false);
99    if ($usedquestion->id != $question->id) {
100        print_error('questionidmismatch', 'question');
101    }
102    $question = $usedquestion;
103    $options->variant = $quba->get_variant($slot);
104
105} else {
106    $quba = question_engine::make_questions_usage_by_activity(
107            'core_question_preview', context_user::instance($USER->id));
108    $quba->set_preferred_behaviour($options->behaviour);
109    $slot = $quba->add_question($question, $options->maxmark);
110
111    if ($options->variant) {
112        $options->variant = min($maxvariant, max(1, $options->variant));
113    } else {
114        $options->variant = rand(1, $maxvariant);
115    }
116
117    $quba->start_question($slot, $options->variant);
118
119    $transaction = $DB->start_delegated_transaction();
120    question_engine::save_questions_usage_by_activity($quba);
121    $transaction->allow_commit();
122}
123$options->behaviour = $quba->get_preferred_behaviour();
124$options->maxmark = $quba->get_question_max_mark($slot);
125
126// Create the settings form, and initialise the fields.
127$optionsform = new preview_options_form(question_preview_form_url($question->id, $context, $previewid),
128        array('quba' => $quba, 'maxvariant' => $maxvariant));
129$optionsform->set_data($options);
130
131// Process change of settings, if that was requested.
132if ($newoptions = $optionsform->get_submitted_data()) {
133    // Set user preferences.
134    $options->save_user_preview_options($newoptions);
135    if (!isset($newoptions->variant)) {
136        $newoptions->variant = $options->variant;
137    }
138    if (isset($newoptions->saverestart)) {
139        restart_preview($previewid, $question->id, $newoptions, $context);
140    }
141}
142
143// Prepare a URL that is used in various places.
144$actionurl = question_preview_action_url($question->id, $quba->get_id(), $options, $context);
145
146// Process any actions from the buttons at the bottom of the form.
147if (data_submitted() && confirm_sesskey()) {
148
149    try {
150
151        if (optional_param('restart', false, PARAM_BOOL)) {
152            restart_preview($previewid, $question->id, $options, $context);
153
154        } else if (optional_param('fill', null, PARAM_BOOL)) {
155            $correctresponse = $quba->get_correct_response($slot);
156            if (!is_null($correctresponse)) {
157                $quba->process_action($slot, $correctresponse);
158
159                $transaction = $DB->start_delegated_transaction();
160                question_engine::save_questions_usage_by_activity($quba);
161                $transaction->allow_commit();
162            }
163            redirect($actionurl);
164
165        } else if (optional_param('finish', null, PARAM_BOOL)) {
166            $quba->process_all_actions();
167            $quba->finish_all_questions();
168
169            $transaction = $DB->start_delegated_transaction();
170            question_engine::save_questions_usage_by_activity($quba);
171            $transaction->allow_commit();
172            redirect($actionurl);
173
174        } else {
175            $quba->process_all_actions();
176
177            $transaction = $DB->start_delegated_transaction();
178            question_engine::save_questions_usage_by_activity($quba);
179            $transaction->allow_commit();
180
181            $scrollpos = optional_param('scrollpos', '', PARAM_RAW);
182            if ($scrollpos !== '') {
183                $actionurl->param('scrollpos', (int) $scrollpos);
184            }
185            redirect($actionurl);
186        }
187
188    } catch (question_out_of_sequence_exception $e) {
189        print_error('submissionoutofsequencefriendlymessage', 'question', $actionurl);
190
191    } catch (Exception $e) {
192        // This sucks, if we display our own custom error message, there is no way
193        // to display the original stack trace.
194        $debuginfo = '';
195        if (!empty($e->debuginfo)) {
196            $debuginfo = $e->debuginfo;
197        }
198        print_error('errorprocessingresponses', 'question', $actionurl,
199                $e->getMessage(), $debuginfo);
200    }
201}
202
203if ($question->length) {
204    $displaynumber = '1';
205} else {
206    $displaynumber = 'i';
207}
208$restartdisabled = array();
209$finishdisabled = array();
210$filldisabled = array();
211if ($quba->get_question_state($slot)->is_finished()) {
212    $finishdisabled = array('disabled' => 'disabled');
213    $filldisabled = array('disabled' => 'disabled');
214}
215// If question type cannot give us a correct response, disable this button.
216if (is_null($quba->get_correct_response($slot))) {
217    $filldisabled = array('disabled' => 'disabled');
218}
219if (!$previewid) {
220    $restartdisabled = array('disabled' => 'disabled');
221}
222
223// Prepare technical info to be output.
224$qa = $quba->get_question_attempt($slot);
225$technical = array();
226$technical[] = get_string('behaviourbeingused', 'question',
227        question_engine::get_behaviour_name($qa->get_behaviour_name()));
228$technical[] = get_string('technicalinfominfraction',     'question', $qa->get_min_fraction());
229$technical[] = get_string('technicalinfomaxfraction',     'question', $qa->get_max_fraction());
230$technical[] = get_string('technicalinfovariant',         'question', $qa->get_variant());
231$technical[] = get_string('technicalinfoquestionsummary', 'question', s($qa->get_question_summary()));
232$technical[] = get_string('technicalinforightsummary',    'question', s($qa->get_right_answer_summary()));
233$technical[] = get_string('technicalinforesponsesummary', 'question', s($qa->get_response_summary()));
234$technical[] = get_string('technicalinfostate',           'question', '' . $qa->get_state());
235
236// Start output.
237$title = get_string('previewquestion', 'question', format_string($question->name));
238$headtags = question_engine::initialise_js() . $quba->render_question_head_html($slot);
239$PAGE->set_title($title);
240$PAGE->set_heading($title);
241echo $OUTPUT->header();
242
243// Start the question form.
244echo html_writer::start_tag('form', array('method' => 'post', 'action' => $actionurl,
245        'enctype' => 'multipart/form-data', 'id' => 'responseform'));
246echo html_writer::start_tag('div');
247echo html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'sesskey', 'value' => sesskey()));
248echo html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'slots', 'value' => $slot));
249echo html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'scrollpos', 'value' => '', 'id' => 'scrollpos'));
250echo html_writer::end_tag('div');
251
252// Output the question.
253echo $quba->render_question($slot, $options, $displaynumber);
254
255// Finish the question form.
256echo html_writer::start_tag('div', array('id' => 'previewcontrols', 'class' => 'controls'));
257echo html_writer::empty_tag('input', $restartdisabled + array('type' => 'submit',
258        'name' => 'restart', 'value' => get_string('restart', 'question'), 'class' => 'btn btn-secondary'));
259echo html_writer::empty_tag('input', $finishdisabled  + array('type' => 'submit',
260        'name' => 'save',    'value' => get_string('save', 'question'), 'class' => 'btn btn-secondary'));
261echo html_writer::empty_tag('input', $filldisabled    + array('type' => 'submit',
262        'name' => 'fill',    'value' => get_string('fillincorrect', 'question'), 'class' => 'btn btn-secondary'));
263echo html_writer::empty_tag('input', $finishdisabled  + array('type' => 'submit',
264        'name' => 'finish',  'value' => get_string('submitandfinish', 'question'), 'class' => 'btn btn-secondary'));
265echo html_writer::end_tag('div');
266echo html_writer::end_tag('form');
267
268// Output the technical info.
269print_collapsible_region_start('', 'techinfo', get_string('technicalinfo', 'question'),
270        'core_question_preview_techinfo_collapsed', true, false, $OUTPUT->help_icon('technicalinfo', 'question'));
271foreach ($technical as $info) {
272    echo html_writer::tag('p', $info, array('class' => 'notifytiny'));
273}
274print_collapsible_region_end();
275
276// Output a link to export this single question.
277if (question_has_capability_on($question, 'view')) {
278    echo html_writer::link(question_get_export_single_question_url($question),
279            get_string('exportonequestion', 'question'));
280}
281
282// Log the preview of this question.
283$event = \core\event\question_viewed::create_from_question_instance($question, $context);
284$event->trigger();
285
286// Display the settings form.
287$optionsform->display();
288
289$PAGE->requires->js_module('core_question_engine');
290$PAGE->requires->strings_for_js(array(
291    'closepreview',
292), 'question');
293$PAGE->requires->yui_module('moodle-question-preview', 'M.question.preview.init');
294echo $OUTPUT->footer();
295
296