moodle/mod/quiz/classes/structure.php

705 lines
24 KiB
PHP

<?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 \mod_quiz\structure class.
*
* @package mod_quiz
* @copyright 2013 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
namespace mod_quiz;
defined('MOODLE_INTERNAL') || die();
/**
* Quiz structure class.
*
* The structure of the quiz. That is, which questions it is built up
* from. This is used on the Edit quiz page (edit.php) and also when
* starting an attempt at the quiz (startattempt.php). Once an attempt
* has been started, then the attempt holds the specific set of questions
* that that student should answer, and we no longer use this class.
*
* @copyright 2014 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class structure {
/** @var \quiz the quiz this is the structure of. */
protected $quizobj = null;
/**
* @var \stdClass[] the questions in this quiz. Contains the row from the questions
* table, with the data from the quiz_slots table added, and also question_categories.contextid.
*/
protected $questions = array();
/** @var \stdClass[] quiz_slots.id => the quiz_slots rows for this quiz, agumented by sectionid. */
protected $slots = array();
/** @var \stdClass[] quiz_slots.slot => the quiz_slots rows for this quiz, agumented by sectionid. */
protected $slotsinorder = array();
/**
* @var \stdClass[] currently a dummy. Holds data that will match the
* quiz_sections, once it exists.
*/
protected $sections = array();
/** @var bool caches the results of can_be_edited. */
protected $canbeedited = null;
/**
* Create an instance of this class representing an empty quiz.
* @return structure
*/
public static function create() {
return new self();
}
/**
* Create an instance of this class representing the structure of a given quiz.
* @param \quiz $quizobj the quiz.
* @return structure
*/
public static function create_for_quiz($quizobj) {
$structure = self::create();
$structure->quizobj = $quizobj;
$structure->populate_structure($quizobj->get_quiz());
return $structure;
}
/**
* Whether there are any questions in the quiz.
* @return bool true if there is at least one question in the quiz.
*/
public function has_questions() {
return !empty($this->questions);
}
/**
* Get the number of questions in the quiz.
* @return int the number of questions in the quiz.
*/
public function get_question_count() {
return count($this->questions);
}
/**
* Get the information about the question with this id.
* @param int $questionid The question id.
* @return \stdClass the data from the questions table, augmented with
* question_category.contextid, and the quiz_slots data for the question in this quiz.
*/
public function get_question_by_id($questionid) {
return $this->questions[$questionid];
}
/**
* Get the information about the question in a given slot.
* @param int $slotnumber the index of the slot in question.
* @return \stdClass the data from the questions table, augmented with
* question_category.contextid, and the quiz_slots data for the question in this quiz.
*/
public function get_question_in_slot($slotnumber) {
return $this->questions[$this->slotsinorder[$slotnumber]->questionid];
}
/**
* Get the course module id of the quiz.
* @return int the course_modules.id for the quiz.
*/
public function get_cmid() {
return $this->quizobj->get_cmid();
}
/**
* Get id of the quiz.
* @return int the quiz.id for the quiz.
*/
public function get_quizid() {
return $this->quizobj->get_quizid();
}
/**
* Get the quiz object.
* @return \stdClass the quiz settings row from the database.
*/
public function get_quiz() {
return $this->quizobj->get_quiz();
}
/**
* Whether the question in the quiz are shuffled for each attempt.
* @return bool true if the questions are shuffled.
*/
public function is_shuffled() {
return $this->quizobj->get_quiz()->shufflequestions;
}
/**
* Quizzes can only be repaginated if they have not been attempted, the
* questions are not shuffled, and there are two or more questions.
* @return bool whether this quiz can be repaginated.
*/
public function can_be_repaginated() {
return !$this->is_shuffled() && $this->can_be_edited()
&& $this->get_question_count() >= 2;
}
/**
* Quizzes can only be edited if they have not been attempted.
* @return bool whether the quiz can be edited.
*/
public function can_be_edited() {
if ($this->canbeedited === null) {
$this->canbeedited = !quiz_has_attempts($this->quizobj->get_quizid());
}
return $this->canbeedited;
}
/**
* This quiz can only be edited if they have not been attempted.
* Throw an exception if this is not the case.
*/
public function check_can_be_edited() {
if (!$this->can_be_edited()) {
$reportlink = quiz_attempt_summary_link_to_reports($this->get_quiz(),
$this->quizobj->get_cm(), $this->quizobj->get_context());
throw new \moodle_exception('cannoteditafterattempts', 'quiz',
new \moodle_url('/mod/quiz/edit.php', array('cmid' => $this->get_cmid())), $reportlink);
}
}
/**
* How many questions are allowed per page in the quiz.
* This setting controls how frequently extra page-breaks should be inserted
* automatically when questions are added to the quiz.
* @return int the number of questions that should be on each page of the
* quiz by default.
*/
public function get_questions_per_page() {
return $this->quizobj->get_quiz()->questionsperpage;
}
/**
* Get quiz slots.
* @return \stdClass[] the slots in this quiz.
*/
public function get_slots() {
return $this->slots;
}
/**
* Is this slot the first one on its page?
* @param int $slotnumber the index of the slot in question.
* @return bool whether this slot the first one on its page.
*/
public function is_first_slot_on_page($slotnumber) {
if ($slotnumber == 1) {
return true;
}
return $this->slotsinorder[$slotnumber]->page != $this->slotsinorder[$slotnumber - 1]->page;
}
/**
* Is this slot the last one on its page?
* @param int $slotnumber the index of the slot in question.
* @return bool whether this slot the last one on its page.
*/
public function is_last_slot_on_page($slotnumber) {
if (!isset($this->slotsinorder[$slotnumber + 1])) {
return true;
}
return $this->slotsinorder[$slotnumber]->page != $this->slotsinorder[$slotnumber + 1]->page;
}
/**
* Is this slot the last one in the quiz?
* @param int $slotnumber the index of the slot in question.
* @return bool whether this slot the last one in the quiz.
*/
public function is_last_slot_in_quiz($slotnumber) {
end($this->slotsinorder);
return $slotnumber == key($this->slotsinorder);
}
/**
* Get the final slot in the quiz.
* @return \stdClass the quiz_slots for for the final slot in the quiz.
*/
public function get_last_slot() {
return end($this->slotsinorder);
}
/**
* Get a slot by it's id. Throws an exception if it is missing.
* @param int $slotid the slot id.
* @return \stdClass the requested quiz_slots row.
*/
public function get_slot_by_id($slotid) {
if (!array_key_exists($slotid, $this->slots)) {
throw new \coding_exception('The \'slotid\' could not be found.');
}
return $this->slots[$slotid];
}
/**
* Get all the questions in a section of the quiz.
* @param int $sectionid the section id.
* @return \stdClass[] of question/slot objects.
*/
public function get_questions_in_section($sectionid) {
$questions = array();
foreach ($this->slotsinorder as $slot) {
if ($slot->sectionid == $sectionid) {
$questions[] = $this->questions[$slot->questionid];
}
}
return $questions;
}
/**
* Get all the sections of the quiz.
* @return \stdClass[] the sections in this quiz.
*/
public function get_quiz_sections() {
return $this->sections;
}
/**
* Get any warnings to show at the top of the edit page.
* @return string[] array of strings.
*/
public function get_edit_page_warnings() {
$warnings = array();
if (quiz_has_attempts($this->quizobj->get_quizid())) {
$reviewlink = quiz_attempt_summary_link_to_reports($this->quizobj->get_quiz(),
$this->quizobj->get_cm(), $this->quizobj->get_context());
$warnings[] = get_string('cannoteditafterattempts', 'quiz', $reviewlink);
}
if ($this->is_shuffled()) {
$updateurl = new \moodle_url('/course/mod.php',
array('return' => 'true', 'update' => $this->quizobj->get_cmid(), 'sesskey' => sesskey()));
$updatelink = '<a href="'.$updateurl->out().'">' . get_string('updatethis', '',
get_string('modulename', 'quiz')) . '</a>';
$warnings[] = get_string('shufflequestionsselected', 'quiz', $updatelink);
}
return $warnings;
}
/**
* Get the date information about the current state of the quiz.
* @return string[] array of two strings. First a short summary, then a longer
* explanation of the current state, e.g. for a tool-tip.
*/
public function get_dates_summary() {
$timenow = time();
$quiz = $this->quizobj->get_quiz();
// Exact open and close dates for the tool-tip.
$dates = array();
if ($quiz->timeopen > 0) {
if ($timenow > $quiz->timeopen) {
$dates[] = get_string('quizopenedon', 'quiz', userdate($quiz->timeopen));
} else {
$dates[] = get_string('quizwillopen', 'quiz', userdate($quiz->timeopen));
}
}
if ($quiz->timeclose > 0) {
if ($timenow > $quiz->timeclose) {
$dates[] = get_string('quizclosed', 'quiz', userdate($quiz->timeclose));
} else {
$dates[] = get_string('quizcloseson', 'quiz', userdate($quiz->timeclose));
}
}
if (empty($dates)) {
$dates[] = get_string('alwaysavailable', 'quiz');
}
$explanation = implode(', ', $dates);
// Brief summary on the page.
if ($timenow < $quiz->timeopen) {
$currentstatus = get_string('quizisclosedwillopen', 'quiz',
userdate($quiz->timeopen, get_string('strftimedatetimeshort', 'langconfig')));
} else if ($quiz->timeclose && $timenow <= $quiz->timeclose) {
$currentstatus = get_string('quizisopenwillclose', 'quiz',
userdate($quiz->timeclose, get_string('strftimedatetimeshort', 'langconfig')));
} else if ($quiz->timeclose && $timenow > $quiz->timeclose) {
$currentstatus = get_string('quizisclosed', 'quiz');
} else {
$currentstatus = get_string('quizisopen', 'quiz');
}
return array($currentstatus, $explanation);
}
/**
* Set up this class with the structure for a given quiz.
* @param \stdClass $quiz the quiz settings.
*/
public function populate_structure($quiz) {
global $DB;
$slots = $DB->get_records_sql("
SELECT slot.id AS slotid, slot.slot, slot.questionid, slot.page, slot.maxmark,
slot.requireprevious, q.*, qc.contextid
FROM {quiz_slots} slot
LEFT JOIN {question} q ON q.id = slot.questionid
LEFT JOIN {question_categories} qc ON qc.id = q.category
WHERE slot.quizid = ?
ORDER BY slot.slot", array($quiz->id));
$slots = $this->populate_missing_questions($slots);
$this->questions = array();
$this->slots = array();
$this->slotsinorder = array();
foreach ($slots as $slotdata) {
$this->questions[$slotdata->questionid] = $slotdata;
$slot = new \stdClass();
$slot->id = $slotdata->slotid;
$slot->slot = $slotdata->slot;
$slot->quizid = $quiz->id;
$slot->page = $slotdata->page;
$slot->questionid = $slotdata->questionid;
$slot->maxmark = $slotdata->maxmark;
$slot->requireprevious = $slotdata->requireprevious;
$this->slots[$slot->id] = $slot;
$this->slotsinorder[$slot->slot] = $slot;
}
$section = new \stdClass();
$section->id = 1;
$section->quizid = $quiz->id;
$section->heading = '';
$section->firstslot = 1;
$section->shuffle = false;
$this->sections = array(1 => $section);
$this->populate_slots_with_sectionids();
$this->populate_question_numbers();
}
/**
* Used by populate. Make up fake data for any missing questions.
* @param \stdClass[] $slots the data about the slots and questions in the quiz.
* @return \stdClass[] updated $slots array.
*/
protected function populate_missing_questions($slots) {
// Address missing question types.
foreach ($slots as $slot) {
if ($slot->qtype === null) {
// If the questiontype is missing change the question type.
$slot->id = $slot->questionid;
$slot->category = 0;
$slot->qtype = 'missingtype';
$slot->name = get_string('missingquestion', 'quiz');
$slot->slot = $slot->slot;
$slot->maxmark = 0;
$slot->requireprevious = 0;
$slot->questiontext = ' ';
$slot->questiontextformat = FORMAT_HTML;
$slot->length = 1;
} else if (!\question_bank::qtype_exists($slot->qtype)) {
$slot->qtype = 'missingtype';
}
}
return $slots;
}
/**
* Fill in the section ids for each slot.
*/
public function populate_slots_with_sectionids() {
$nextsection = reset($this->sections);
foreach ($this->slotsinorder as $slot) {
if ($slot->slot == $nextsection->firstslot) {
$currentsectionid = $nextsection->id;
$nextsection = next($this->sections);
if (!$nextsection) {
$nextsection = new \stdClass();
$nextsection->firstslot = -1;
}
}
$slot->sectionid = $currentsectionid;
}
}
/**
* Number the questions.
*/
protected function populate_question_numbers() {
$number = 1;
foreach ($this->slots as $slot) {
$question = $this->questions[$slot->questionid];
if ($question->length == 0) {
$question->displayednumber = get_string('infoshort', 'quiz');
} else {
$question->displayednumber = $number;
$number += 1;
}
}
}
/**
* Move a slot from its current location to a new location.
*
* After callig this method, this class will be in an invalid state, and
* should be discarded if you want to manipulate the structure further.
*
* @param int $idmove id of slot to be moved
* @param int $idbefore id of slot to come before slot being moved
* @param int $page new page number of slot being moved
* @return void
*/
public function move_slot($idmove, $idbefore, $page) {
global $DB;
$this->check_can_be_edited();
$movingslot = $this->slots[$idmove];
if (empty($movingslot)) {
throw new moodle_exception('Bad slot ID ' . $idmove);
}
$movingslotnumber = (int) $movingslot->slot;
// Empty target slot means move slot to first.
if (empty($idbefore)) {
$targetslotnumber = 0;
} else {
$targetslotnumber = (int) $this->slots[$idbefore]->slot;
}
// Work out how things are being moved.
$slotreorder = array();
if ($targetslotnumber > $movingslotnumber) {
$slotreorder[$movingslotnumber] = $targetslotnumber;
for ($i = $movingslotnumber; $i < $targetslotnumber; $i++) {
$slotreorder[$i + 1] = $i;
}
} else if ($targetslotnumber < $movingslotnumber - 1) {
$slotreorder[$movingslotnumber] = $targetslotnumber + 1;
for ($i = $targetslotnumber + 1; $i < $movingslotnumber; $i++) {
$slotreorder[$i] = $i + 1;
}
}
$trans = $DB->start_delegated_transaction();
// Slot has moved record new order.
if ($slotreorder) {
update_field_with_unique_index('quiz_slots', 'slot', $slotreorder,
array('quizid' => $this->get_quizid()));
}
// Page has changed. Record it.
if (!$page) {
$page = 1;
}
if ($movingslot->page != $page) {
$DB->set_field('quiz_slots', 'page', $page,
array('id' => $movingslot->id));
}
$emptypages = $DB->get_fieldset_sql("
SELECT DISTINCT page - 1
FROM {quiz_slots} slot
WHERE quizid = ?
AND page > 1
AND NOT EXISTS (SELECT 1 FROM {quiz_slots} WHERE quizid = ? AND page = slot.page - 1)
ORDER BY page - 1 DESC
", array($this->get_quizid(), $this->get_quizid()));
foreach ($emptypages as $page) {
$DB->execute("
UPDATE {quiz_slots}
SET page = page - 1
WHERE quizid = ?
AND page > ?
", array($this->get_quizid(), $page));
}
$trans->allow_commit();
}
/**
* Refresh page numbering of quiz slots.
* @param \stdClass $quiz the quiz object.
* @param \stdClass[] $slots (optional) array of slot objects.
* @return \stdClass[] array of slot objects.
*/
public function refresh_page_numbers($quiz, $slots=array()) {
global $DB;
// Get slots ordered by page then slot.
if (!count($slots)) {
$slots = $DB->get_records('quiz_slots', array('quizid' => $quiz->id), 'slot, page');
}
// Loop slots. Start Page number at 1 and increment as required.
$pagenumbers = array('new' => 0, 'old' => 0);
foreach ($slots as $slot) {
if ($slot->page !== $pagenumbers['old']) {
$pagenumbers['old'] = $slot->page;
++$pagenumbers['new'];
}
if ($pagenumbers['new'] == $slot->page) {
continue;
}
$slot->page = $pagenumbers['new'];
}
return $slots;
}
/**
* Refresh page numbering of quiz slots and save to the database.
* @param \stdClass $quiz the quiz object.
* @return \stdClass[] array of slot objects.
*/
public function refresh_page_numbers_and_update_db($quiz) {
global $DB;
$this->check_can_be_edited();
$slots = $this->refresh_page_numbers($quiz);
// Record new page order.
foreach ($slots as $slot) {
$DB->set_field('quiz_slots', 'page', $slot->page,
array('id' => $slot->id));
}
return $slots;
}
/**
* Remove a slot from a quiz
* @param \stdClass $quiz the quiz object.
* @param int $slotnumber The number of the slot to be deleted.
*/
public function remove_slot($quiz, $slotnumber) {
global $DB;
$this->check_can_be_edited();
$slot = $DB->get_record('quiz_slots', array('quizid' => $quiz->id, 'slot' => $slotnumber));
$maxslot = $DB->get_field_sql('SELECT MAX(slot) FROM {quiz_slots} WHERE quizid = ?', array($quiz->id));
if (!$slot) {
return;
}
$trans = $DB->start_delegated_transaction();
$DB->delete_records('quiz_slots', array('id' => $slot->id));
for ($i = $slot->slot + 1; $i <= $maxslot; $i++) {
$DB->set_field('quiz_slots', 'slot', $i - 1,
array('quizid' => $quiz->id, 'slot' => $i));
}
$qtype = $DB->get_field('question', 'qtype', array('id' => $slot->questionid));
if ($qtype === 'random') {
// This function automatically checks if the question is in use, and won't delete if it is.
question_delete_question($slot->questionid);
}
unset($this->questions[$slot->questionid]);
$this->refresh_page_numbers_and_update_db($quiz);
$trans->allow_commit();
}
/**
* Change the max mark for a slot.
*
* Saves changes to the question grades in the quiz_slots table and any
* corresponding question_attempts.
* It does not update 'sumgrades' in the quiz table.
*
* @param \stdClass $slot row from the quiz_slots table.
* @param float $maxmark the new maxmark.
* @return bool true if the new grade is different from the old one.
*/
public function update_slot_maxmark($slot, $maxmark) {
global $DB;
if (abs($maxmark - $slot->maxmark) < 1e-7) {
// Grade has not changed. Nothing to do.
return false;
}
$trans = $DB->start_delegated_transaction();
$slot->maxmark = $maxmark;
$DB->update_record('quiz_slots', $slot);
\question_engine::set_max_mark_in_attempts(new \qubaids_for_quiz($slot->quizid),
$slot->slot, $maxmark);
$trans->allow_commit();
return true;
}
/**
* Change require previous for a slot..
* @param \stdClass $slot row from the quiz_slots table.
*/
public function update_question_dependency($slot) {
global $DB;
$trans = $DB->start_delegated_transaction();
// Swap dependency setting.
if ($slot->requireprevious == 1) {
$slot->requireprevious = 0;
} else {
$slot->requireprevious = 1;
}
$DB->update_record('quiz_slots', $slot);
$trans->allow_commit();
}
/**
* Add/Remove a pagebreak.
*
* Saves changes to the slot page relationship in the quiz_slots table and reorders the paging
* for subsequent slots.
*
* @param \stdClass $quiz the quiz object.
* @param int $slotid id of slot.
* @param int $type repaginate::LINK or repaginate::UNLINK.
* @return \stdClass[] array of slot objects.
*/
public function update_page_break($quiz, $slotid, $type) {
global $DB;
$this->check_can_be_edited();
$quizslots = $DB->get_records('quiz_slots', array('quizid' => $quiz->id), 'slot');
$repaginate = new \mod_quiz\repaginate($quiz->id, $quizslots);
$repaginate->repaginate_slots($quizslots[$slotid]->slot, $type);
$slots = $this->refresh_page_numbers_and_update_db($quiz);
return $slots;
}
}