Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Data provider.

 *

 * @package    mod_lesson

 * @copyright  2018 Frédéric Massart

 * @author     Frédéric Massart <fred@branchup.tech>

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

 */

namespace mod_lesson\privacy;

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

use context;

use context_helper;

use context_module;

use stdClass;

use core_privacy\local\metadata\collection;

use core_privacy\local\request\approved_contextlist;

use core_privacy\local\request\approved_userlist;

use core_privacy\local\request\helper;

use core_privacy\local\request\transform;

use core_privacy\local\request\userlist;

use core_privacy\local\request\writer;

require_once($CFG->dirroot . '/mod/lesson/locallib.php');

require_once($CFG->dirroot . '/mod/lesson/pagetypes/essay.php');

require_once($CFG->dirroot . '/mod/lesson/pagetypes/matching.php');

require_once($CFG->dirroot . '/mod/lesson/pagetypes/multichoice.php');

/**

 * Data provider class.

 *

 * @package    mod_lesson

 * @copyright  2018 Frédéric Massart

 * @author     Frédéric Massart <fred@branchup.tech>

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

 */

class provider implements

    \core_privacy\local\metadata\provider,

    \core_privacy\local\request\core_userlist_provider,

    \core_privacy\local\request\plugin\provider,

    \core_privacy\local\request\user_preference_provider {

    /**

     * Returns metadata.

     *

     * @param collection $collection The initialised collection to add items to.

     * @return collection A listing of user data stored through this system.

     */

    public static function get_metadata(collection $collection): collection {

        $collection->add_database_table('lesson_attempts', [

            'userid' => 'privacy:metadata:attempts:userid',

            'pageid' => 'privacy:metadata:attempts:pageid',

            'answerid' => 'privacy:metadata:attempts:answerid',

            'retry' => 'privacy:metadata:attempts:retry',

            'correct' => 'privacy:metadata:attempts:correct',

            'useranswer' => 'privacy:metadata:attempts:useranswer',

            'timeseen' => 'privacy:metadata:attempts:timeseen',

        ], 'privacy:metadata:attempts');

        $collection->add_database_table('lesson_grades', [

            'userid' => 'privacy:metadata:grades:userid',

            'grade' => 'privacy:metadata:grades:grade',

            'completed' => 'privacy:metadata:grades:completed',

            // The column late is not used.

        ], 'privacy:metadata:grades');

        $collection->add_database_table('lesson_timer', [

            'userid' => 'privacy:metadata:timer:userid',

            'starttime' => 'privacy:metadata:timer:starttime',

            'lessontime' => 'privacy:metadata:timer:lessontime',

            'completed' => 'privacy:metadata:timer:completed',

            'timemodifiedoffline' => 'privacy:metadata:timer:timemodifiedoffline',

        ], 'privacy:metadata:timer');

        $collection->add_database_table('lesson_branch', [

            'userid' => 'privacy:metadata:branch:userid',

            'pageid' => 'privacy:metadata:branch:pageid',

            'retry' => 'privacy:metadata:branch:retry',

            'flag' => 'privacy:metadata:branch:flag',

            'timeseen' => 'privacy:metadata:branch:timeseen',

            'nextpageid' => 'privacy:metadata:branch:nextpageid',

        ], 'privacy:metadata:branch');

        $collection->add_database_table('lesson_overrides', [

            'userid' => 'privacy:metadata:overrides:userid',

            'available' => 'privacy:metadata:overrides:available',

            'deadline' => 'privacy:metadata:overrides:deadline',

            'timelimit' => 'privacy:metadata:overrides:timelimit',

            'review' => 'privacy:metadata:overrides:review',

            'maxattempts' => 'privacy:metadata:overrides:maxattempts',

            'retake' => 'privacy:metadata:overrides:retake',

            'password' => 'privacy:metadata:overrides:password',

        ], 'privacy:metadata:overrides');

        $collection->add_user_preference('lesson_view', 'privacy:metadata:userpref:lessonview');

        return $collection;

    }

    /**

     * Get the list of contexts that contain user information for the specified user.

     *

     * @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): \core_privacy\local\request\contextlist {

        $contextlist = new \core_privacy\local\request\contextlist();

        $sql = "

            SELECT DISTINCT ctx.id

              FROM {lesson} l

              JOIN {modules} m

                ON m.name = :lesson

              JOIN {course_modules} cm

                ON cm.instance = l.id

               AND cm.module = m.id

              JOIN {context} ctx

                ON ctx.instanceid = cm.id

               AND ctx.contextlevel = :modulelevel

         LEFT JOIN {lesson_attempts} la

                ON la.lessonid = l.id

               AND la.userid = :userid1

         LEFT JOIN {lesson_branch} lb

                ON lb.lessonid = l.id

               AND lb.userid = :userid2

         LEFT JOIN {lesson_grades} lg

                ON lg.lessonid = l.id

               AND lg.userid = :userid3

         LEFT JOIN {lesson_overrides} lo

                ON lo.lessonid = l.id

               AND lo.userid = :userid4

         LEFT JOIN {lesson_timer} lt

                ON lt.lessonid = l.id

               AND lt.userid = :userid5

             WHERE la.id IS NOT NULL

                OR lb.id IS NOT NULL

                OR lg.id IS NOT NULL

                OR lo.id IS NOT NULL

                OR lt.id IS NOT NULL";

        $params = [

            'lesson' => 'lesson',

            'modulelevel' => CONTEXT_MODULE,

            'userid1' => $userid,

            'userid2' => $userid,

            'userid3' => $userid,

            'userid4' => $userid,

            'userid5' => $userid,

        ];

        $contextlist->add_from_sql($sql, $params);

        return $contextlist;

    }

    /**

     * Get the list of users who have data within a context.

     *

     * @param   userlist    $userlist   The userlist containing the list of users who have data in this context/plugin combination.

     *

     */

    public static function get_users_in_context(userlist $userlist) {

        $context = $userlist->get_context();

        if (!is_a($context, \context_module::class)) {

            return;

        }

        $params = [

            'lesson' => 'lesson',

            'modulelevel' => CONTEXT_MODULE,

            'contextid' => $context->id,

        ];

        // Mapping of lesson tables which may contain user data.

        $joins = [

            'lesson_attempts',

            'lesson_branch',

            'lesson_grades',

            'lesson_overrides',

            'lesson_timer',

        ];

        foreach ($joins as $join) {

            $sql = "

                SELECT lx.userid

                  FROM {lesson} l

                  JOIN {modules} m

                    ON m.name = :lesson

                  JOIN {course_modules} cm

                    ON cm.instance = l.id

                   AND cm.module = m.id

                  JOIN {context} ctx

                    ON ctx.instanceid = cm.id

                   AND ctx.contextlevel = :modulelevel

                  JOIN {{$join}} lx

                    ON lx.lessonid = l.id

                 WHERE ctx.id = :contextid";

            $userlist->add_from_sql('userid', $sql, $params);

        }

    }

    /**

     * Export all user data for the specified user, in the specified contexts.

     *

     * @param approved_contextlist $contextlist The approved contexts to export information for.

     */

    public static function export_user_data(approved_contextlist $contextlist) {

        global $DB;

        $user = $contextlist->get_user();

        $userid = $user->id;

        $cmids = array_reduce($contextlist->get_contexts(), function($carry, $context) {

            if ($context->contextlevel == CONTEXT_MODULE) {

                $carry[] = $context->instanceid;

            }

            return $carry;

        }, []);

        if (empty($cmids)) {

            return;

        }

        // If the context export was requested, then let's at least describe the lesson.

        foreach ($cmids as $cmid) {

            $context = context_module::instance($cmid);

            $contextdata = helper::get_context_data($context, $user);

            helper::export_context_files($context, $user);

            writer::with_context($context)->export_data([], $contextdata);

        }

        // Find the lesson IDs.

        $lessonidstocmids = static::get_lesson_ids_to_cmids_from_cmids($cmids);

        // Prepare the common SQL fragments.

        list($inlessonsql, $inlessonparams) = $DB->get_in_or_equal(array_keys($lessonidstocmids), SQL_PARAMS_NAMED);

        $sqluserlesson = "userid = :userid AND lessonid $inlessonsql";

        $paramsuserlesson = array_merge($inlessonparams, ['userid' => $userid]);

        // Export the overrides.

        $recordset = $DB->get_recordset_select('lesson_overrides', $sqluserlesson, $paramsuserlesson);

        static::recordset_loop_and_export($recordset, 'lessonid', null, function($carry, $record) {

            // We know that there is only one row per lesson, so no need to use $carry.

            return (object) [

                'available' => $record->available !== null ? transform::datetime($record->available) : null,

                'deadline' => $record->deadline !== null ? transform::datetime($record->deadline) : null,

                'timelimit' => $record->timelimit !== null ? format_time($record->timelimit) : null,

                'review' => $record->review !== null ? transform::yesno($record->review) : null,

                'maxattempts' => $record->maxattempts,

                'retake' => $record->retake !== null ? transform::yesno($record->retake) : null,

                'password' => $record->password,

            ];

        }, function($lessonid, $data) use ($lessonidstocmids) {

            $context = context_module::instance($lessonidstocmids[$lessonid]);

            writer::with_context($context)->export_related_data([], 'overrides', $data);

        });

        // Export the grades.

        $recordset = $DB->get_recordset_select('lesson_grades', $sqluserlesson, $paramsuserlesson, 'lessonid, completed');

        static::recordset_loop_and_export($recordset, 'lessonid', [], function($carry, $record) {

            $carry[] = (object) [

                'grade' => $record->grade,

                'completed' => transform::datetime($record->completed),

            ];

            return $carry;

        }, function($lessonid, $data) use ($lessonidstocmids) {

            $context = context_module::instance($lessonidstocmids[$lessonid]);

            writer::with_context($context)->export_related_data([], 'grades', (object) ['grades' => $data]);

        });

        // Export the timers.

        $recordset = $DB->get_recordset_select('lesson_timer', $sqluserlesson, $paramsuserlesson, 'lessonid, starttime');

        static::recordset_loop_and_export($recordset, 'lessonid', [], function($carry, $record) {

            $carry[] = (object) [

                'starttime' => transform::datetime($record->starttime),

                'lastactivity' => transform::datetime($record->lessontime),

                'completed' => transform::yesno($record->completed),

                'timemodifiedoffline' => $record->timemodifiedoffline ? transform::datetime($record->timemodifiedoffline) : null,

            ];

            return $carry;

        }, function($lessonid, $data) use ($lessonidstocmids) {

            $context = context_module::instance($lessonidstocmids[$lessonid]);

            writer::with_context($context)->export_related_data([], 'timers', (object) ['timers' => $data]);

        });

        // Export the attempts and branches.

        $sql = "

            SELECT " . $DB->sql_concat('lp.id', "':'", 'COALESCE(la.id, 0)', "':'", 'COALESCE(lb.id, 0)') . " AS uniqid,

                   lp.lessonid,

                   lp.id AS page_id,

                   lp.qtype AS page_qtype,

                   lp.qoption AS page_qoption,

                   lp.title AS page_title,

                   lp.contents AS page_contents,

                   lp.contentsformat AS page_contentsformat,

                   la.id AS attempt_id,

                   la.retry AS attempt_retry,

                   la.correct AS attempt_correct,

                   la.useranswer AS attempt_useranswer,

                   la.timeseen AS attempt_timeseen,

                   lb.id AS branch_id,

                   lb.retry AS branch_retry,

                   lb.timeseen AS branch_timeseen,

                   lpb.id AS nextpage_id,

                   lpb.title AS nextpage_title

              FROM {lesson_pages} lp

         LEFT JOIN {lesson_attempts} la

                ON la.pageid = lp.id

               AND la.userid = :userid1

         LEFT JOIN {lesson_branch} lb

                ON lb.pageid = lp.id

               AND lb.userid = :userid2

         LEFT JOIN {lesson_pages} lpb

                ON lpb.id = lb.nextpageid

             WHERE lp.lessonid $inlessonsql

               AND (la.id IS NOT NULL OR lb.id IS NOT NULL)

          ORDER BY lp.lessonid, lp.id, la.retry, lb.retry, la.id, lb.id";

        $params = array_merge($inlessonparams, ['userid1' => $userid, 'userid2' => $userid]);

        $recordset = $DB->get_recordset_sql($sql, $params);

        static::recordset_loop_and_export($recordset, 'lessonid', [], function($carry, $record) use ($lessonidstocmids) {

            $context = context_module::instance($lessonidstocmids[$record->lessonid]);

            $options = ['context' => $context];

            $take = isset($record->attempt_retry) ? $record->attempt_retry : $record->branch_retry;

            if (!isset($carry[$take])) {

                $carry[$take] = (object) [

                    'number' => $take + 1,

                    'answers' => [],

                    'jumps' => []

                ];

            }

            $pagefilespath = [get_string('privacy:path:pages', 'mod_lesson'), $record->page_id];

            writer::with_context($context)->export_area_files($pagefilespath, 'mod_lesson', 'page_contents', $record->page_id);

            $pagecontents = format_text(

                writer::with_context($context)->rewrite_pluginfile_urls(

                    $pagefilespath,

                    'mod_lesson',

                    'page_contents',

                    $record->page_id,

                    $record->page_contents

                ),

                $record->page_contentsformat,

                $options

            );

            $pagebase = [

                'id' => $record->page_id,

                'page' => $record->page_title,

                'contents' => $pagecontents,

                'contents_files_folder' => implode('/', $pagefilespath)

            ];

            if (isset($record->attempt_id)) {

                $carry[$take]->answers[] = array_merge($pagebase, static::transform_attempt($record, $context));

            } else if (isset($record->branch_id)) {

                if (!empty($record->nextpage_id)) {

                    $wentto = $record->nextpage_title . " (id: {$record->nextpage_id})";

                } else {

                    $wentto = get_string('endoflesson', 'mod_lesson');

                }

                $carry[$take]->jumps[] = array_merge($pagebase, [

                    'went_to' => $wentto,

                    'timeseen' => transform::datetime($record->attempt_timeseen)

                ]);

            }

            return $carry;

        }, function($lessonid, $data) use ($lessonidstocmids) {

            $context = context_module::instance($lessonidstocmids[$lessonid]);

            writer::with_context($context)->export_related_data([], 'attempts', (object) [

                'attempts' => array_values($data)

            ]);

        });

    }

    /**

     * Export all user preferences for the plugin.

     *

     * @param int $userid The userid of the user whose data is to be exported.

     */

    public static function export_user_preferences(int $userid) {

        $lessonview = get_user_preferences('lesson_view', null, $userid);

        if ($lessonview !== null) {

            $value = $lessonview;

            // The code seems to indicate that there also is the option 'simple', but it's not

            // described nor accessible from anywhere so we won't describe it more than being 'simple'.

            if ($lessonview == 'full') {

                $value = get_string('full', 'mod_lesson');

            } else if ($lessonview == 'collapsed') {

                $value = get_string('collapsed', 'mod_lesson');

            }

            writer::export_user_preference('mod_lesson', 'lesson_view', $lessonview,

                get_string('privacy:metadata:userpref:lessonview', 'mod_lesson'));

        }

    }

    /**

     * Delete all data for all users in the specified context.

     *

     * @param context $context The specific context to delete data for.

     */

    public static function delete_data_for_all_users_in_context(context $context) {

        global $DB;

        if ($context->contextlevel != CONTEXT_MODULE) {

            return;

        }

        if (!$lessonid = static::get_lesson_id_from_context($context)) {

            return;

        }

        $DB->delete_records('lesson_attempts', ['lessonid' => $lessonid]);

        $DB->delete_records('lesson_branch', ['lessonid' => $lessonid]);

        $DB->delete_records('lesson_grades', ['lessonid' => $lessonid]);

        $DB->delete_records('lesson_timer', ['lessonid' => $lessonid]);

        $DB->delete_records_select('lesson_overrides', 'lessonid = :id AND userid IS NOT NULL', ['id' => $lessonid]);

        $fs = get_file_storage();

        $fs->delete_area_files($context->id, 'mod_lesson', 'essay_responses');

        $fs->delete_area_files($context->id, 'mod_lesson', 'essay_answers');

    }

    /**

     * 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.

     */

    public static function delete_data_for_user(approved_contextlist $contextlist) {

        global $DB;

        $userid = $contextlist->get_user()->id;

        $cmids = array_reduce($contextlist->get_contexts(), function($carry, $context) {

            if ($context->contextlevel == CONTEXT_MODULE) {

                $carry[] = $context->instanceid;

            }

            return $carry;

        }, []);

        if (empty($cmids)) {

            return;

        }

        // Find the lesson IDs.

        $lessonidstocmids = static::get_lesson_ids_to_cmids_from_cmids($cmids);

        $lessonids = array_keys($lessonidstocmids);

        if (empty($lessonids)) {

            return;

        }

        // Prepare the SQL we'll need below.

        list($insql, $inparams) = $DB->get_in_or_equal($lessonids, SQL_PARAMS_NAMED);

        $sql = "lessonid $insql AND userid = :userid";

        $params = array_merge($inparams, ['userid' => $userid]);

        // Delete the attempt files.

        $fs = get_file_storage();

        $recordset = $DB->get_recordset_select('lesson_attempts', $sql, $params, '', 'id, lessonid');

        foreach ($recordset as $record) {

            $cmid = $lessonidstocmids[$record->lessonid];

            $context = context_module::instance($cmid);

            $fs->delete_area_files($context->id, 'mod_lesson', 'essay_responses', $record->id);

            $fs->delete_area_files($context->id, 'mod_lesson', 'essay_answers', $record->id);

        }

        $recordset->close();

        // Delete all the things.

        $DB->delete_records_select('lesson_attempts', $sql, $params);

        $DB->delete_records_select('lesson_branch', $sql, $params);

        $DB->delete_records_select('lesson_grades', $sql, $params);

        $DB->delete_records_select('lesson_timer', $sql, $params);

        $DB->delete_records_select('lesson_overrides', $sql, $params);

    }

    /**

     * Delete multiple users within a single context.

     *

     * @param   approved_userlist    $userlist The approved context and user information to delete information for.

     */

    public static function delete_data_for_users(approved_userlist $userlist) {

        global $DB;

        $context = $userlist->get_context();

        $lessonid = static::get_lesson_id_from_context($context);

        $userids = $userlist->get_userids();

        if (empty($lessonid)) {

            return;

        }

        // Prepare the SQL we'll need below.

        list($insql, $inparams) = $DB->get_in_or_equal($userids, SQL_PARAMS_NAMED);

        $sql = "lessonid = :lessonid AND userid {$insql}";

        $params = array_merge($inparams, ['lessonid' => $lessonid]);

        // Delete the attempt files.

        $fs = get_file_storage();

        $recordset = $DB->get_recordset_select('lesson_attempts', $sql, $params, '', 'id, lessonid');

        foreach ($recordset as $record) {

            $fs->delete_area_files($context->id, 'mod_lesson', 'essay_responses', $record->id);

            $fs->delete_area_files($context->id, 'mod_lesson', 'essay_answers', $record->id);

        }

        $recordset->close();

        // Delete all the things.

        $DB->delete_records_select('lesson_attempts', $sql, $params);

        $DB->delete_records_select('lesson_branch', $sql, $params);

        $DB->delete_records_select('lesson_grades', $sql, $params);

        $DB->delete_records_select('lesson_timer', $sql, $params);

        $DB->delete_records_select('lesson_overrides', $sql, $params);

    }

    /**

     * Get a survey ID from its context.

     *

     * @param context_module $context The module context.

     * @return int

     */

    protected static function get_lesson_id_from_context(context_module $context) {

        $cm = get_coursemodule_from_id('lesson', $context->instanceid);

        return $cm ? (int) $cm->instance : 0;

    }

    /**

     * Return a dict of lesson IDs mapped to their course module ID.

     *

     * @param array $cmids The course module IDs.

     * @return array In the form of [$lessonid => $cmid].

     */

    protected static function get_lesson_ids_to_cmids_from_cmids(array $cmids) {

        global $DB;

        list($insql, $inparams) = $DB->get_in_or_equal($cmids, SQL_PARAMS_NAMED);

        $sql = "

            SELECT l.id, cm.id AS cmid

              FROM {lesson} l

              JOIN {modules} m

                ON m.name = :lesson

              JOIN {course_modules} cm

                ON cm.instance = l.id

               AND cm.module = m.id

             WHERE cm.id $insql";

        $params = array_merge($inparams, ['lesson' => 'lesson']);

        return $DB->get_records_sql_menu($sql, $params);

    }

    /**

     * Loop and export from a recordset.

     *

     * @param moodle_recordset $recordset The recordset.

     * @param string $splitkey The record key to determine when to export.

     * @param mixed $initial The initial data to reduce from.

     * @param callable $reducer The function to return the dataset, receives current dataset, and the current record.

     * @param callable $export The function to export the dataset, receives the last value from $splitkey and the dataset.

     * @return void

     */

    protected static function recordset_loop_and_export(\moodle_recordset $recordset, $splitkey, $initial,

            callable $reducer, callable $export) {

        $data = $initial;

        $lastid = null;

        foreach ($recordset as $record) {

            if ($lastid && $record->{$splitkey} != $lastid) {

                $export($lastid, $data);

                $data = $initial;

            }

            $data = $reducer($data, $record);

            $lastid = $record->{$splitkey};

        }

        $recordset->close();

        if (!empty($lastid)) {

            $export($lastid, $data);

        }

    }

    /**

     * Transform an attempt.

     *

     * @param stdClass $data Data from the database, as per the exporting method.

     * @param context_module $context The module context.

     * @return array

     */

    protected static function transform_attempt(stdClass $data, context_module $context) {

        global $DB;

        $options = ['context' => $context];

        $answer = $data->attempt_useranswer;

        $response = null;

        $responsefilesfolder = null;

        if ($answer !== null) {

            if ($data->page_qtype == LESSON_PAGE_ESSAY) {

                // Essay questions serialise data in the answer field.

                $info = \lesson_page_type_essay::extract_useranswer($answer);

                $answerfilespath = [get_string('privacy:path:essayanswers', 'mod_lesson'), $data->attempt_id];

                $answer = format_text(

                    writer::with_context($context)->rewrite_pluginfile_urls(

                        $answerfilespath,

                        'mod_lesson',

                        'essay_answers',

                        $data->attempt_id,

                        $info->answer

                    ),

                    $info->answerformat,

                    $options

                );

                writer::with_context($context)->export_area_files($answerfilespath, 'mod_lesson',

                    'essay_answers', $data->page_id);

                if ($info->response !== null) {

                    // We export the files in a subfolder to avoid conflicting files, and tell the user

                    // where those files were exported. That is because we are not using a subfolder for

                    // every single essay response.

                    $responsefilespath = [get_string('privacy:path:essayresponses', 'mod_lesson'), $data->attempt_id];

                    $responsefilesfolder = implode('/', $responsefilespath);

                    $response = format_text(

                        writer::with_context($context)->rewrite_pluginfile_urls(

                            $responsefilespath,

                            'mod_lesson',

                            'essay_responses',

                            $data->attempt_id,

                            $info->response

                        ),

                        $info->responseformat,

                        $options

                    );

                    writer::with_context($context)->export_area_files($responsefilespath, 'mod_lesson',

                        'essay_responses', $data->page_id);

                }

            } else if ($data->page_qtype == LESSON_PAGE_MULTICHOICE && $data->page_qoption) {

                // Multiple choice quesitons with multiple answers encode the answers.

                list($insql, $inparams) = $DB->get_in_or_equal(explode(',', $answer), SQL_PARAMS_NAMED);

                $orderby = 'id, ' . $DB->sql_order_by_text('answer') . ', answerformat';

                $records = $DB->get_records_select('lesson_answers', "id $insql", $inparams, $orderby);

                $answer = array_values(array_map(function($record) use ($options) {

                    return format_text($record->answer, $record->answerformat, $options);

                }, empty($records) ? [] : $records));

            } else if ($data->page_qtype == LESSON_PAGE_MATCHING) {

                // Matching questions need sorting.

                $chosen = explode(',', $answer);

                $answers = $DB->get_records_select('lesson_answers', 'pageid = :pageid', ['pageid' => $data->page_id],

                    'id', 'id, answer, answerformat', 2); // The two first entries are not options.

                $i = -1;

                $answer = array_values(array_map(function($record) use (&$i, $chosen, $options) {

                    $i++;

                    return [

                        'label' => format_text($record->answer, $record->answerformat, $options),

                        'matched_with' => array_key_exists($i, $chosen) ? $chosen[$i] : null

                    ];

                }, empty($answers) ? [] : $answers));

            }

        }

        $result = [

            'answer' => $answer,

            'correct' => transform::yesno($data->attempt_correct),

            'timeseen' => transform::datetime($data->attempt_timeseen),

        ];

        if ($response !== null) {

            $result['response'] = $response;

            $result['response_files_folder'] = $responsefilesfolder;

        }

        return $result;

    }

}