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/>.

namespace mod_bigbluebuttonbn;

use cm_info;

use context;

use context_course;

use context_module;

use core\dml\table;

use mod_bigbluebuttonbn\local\config;

use mod_bigbluebuttonbn\local\helpers\files;

use mod_bigbluebuttonbn\local\helpers\roles;

use mod_bigbluebuttonbn\local\proxy\bigbluebutton_proxy;

use moodle_url;

use stdClass;

/**

 * Instance record for mod_bigbluebuttonbn.

 *

 * @package   mod_bigbluebuttonbn

 * @copyright 2021 Andrew Lyons <andrew@nicols.co.uk>

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

 */

class instance {

    /** @var int Defines an instance type that includes room and recordings */

    public const TYPE_ALL = 0;

    /** @var int Defines an instance type that includes only room */

    public const TYPE_ROOM_ONLY = 1;

    /** @var int Defines an instance type that includes only recordings */

    public const TYPE_RECORDING_ONLY = 2;

    /** @var cm_info The cm_info object relating to the instance */

    protected $cm;

    /** @var stdClass The course that the instance is in */

    protected $course;

    /** @var stdClass The instance data for the instance */

    protected $instancedata;

    /** @var context The current context */

    protected $context;

    /** @var array The list of participants */

    protected $participantlist;

    /** @var int The current groupid if set */

    protected $groupid;

    /** @var int The course module id. */

    protected $cmid;

    /**

     * Instance constructor.

     *

     * Never called directly. Use self::get_from_instanceid or self::get_from_cmid.

     *

     * @param int $cmid

     * @param stdClass $course

     * @param stdClass $instancedata

     * @param int|null $groupid

     */

    private function __construct(int $cmid, stdClass $course, stdClass $instancedata, ?int $groupid = null) {

        $this->cmid = $cmid;

        $this->cm = null; // This is not retrieved later, whenever we call ::get_cm() it will be retrieved.

        $this->course = $course;

        $this->instancedata = $instancedata;

        $this->groupid = $groupid;

    }

    /**

     * Get a group instance of the specified instance.

     *

     * @param self $originalinstance

     * @param int $groupid

     * @return null|self

     */

    public static function get_group_instance_from_instance(self $originalinstance, int $groupid): ?self {

        return new self(

            $originalinstance->get_cm_id(),

            $originalinstance->get_course(),

            $originalinstance->get_instance_data(),

            $groupid

        );

    }

    /**

     * Get the instance information from an instance id.

     *

     * @param int $instanceid The id from the bigbluebuttonbn table

     * @return null|self

     */

    public static function get_from_instanceid(int $instanceid): ?self {

        return self::get_instance_info_retriever($instanceid, self::IDTYPE_INSTANCEID);

    }

    /**

     * Get the instance information from a cmid.

     *

     * @param int $cmid

     * @return null|self

     */

    public static function get_from_cmid(int $cmid): ?self {

        return self::get_instance_info_retriever($cmid, self::IDTYPE_CMID);

    }

    /**

     * Get the instance information from a cmid.

     */

    const IDTYPE_CMID = 0;

    /**

     * Get the instance information from an id.

     */

    const IDTYPE_INSTANCEID = 1;

    /**

     * Helper to get the instance information from an id.

     *

     * Used by self::get_from_id and self::get_cmid.

     *

     * @param int $id The id to look for.

     * @param int $idtype self::IDTYPE_CMID or self::IDTYPE_INSTANCEID

     * @return null|self

     * @throws \moodle_exception

     */

    private static function get_instance_info_retriever(int $id, int $idtype = self::IDTYPE_INSTANCEID): ?self {

        global $DB;

        if (!in_array($idtype, [self::IDTYPE_CMID, self::IDTYPE_INSTANCEID])) {

            throw new \moodle_exception('Invalid idtype');

        }

        [

            'coursetable' => $coursetable,

            'courseselect' => $courseselect,

            'coursefrom' => $coursefrom,

            'cmfrom' => $cmfrom,

            'cmselect' => $cmselect,

            'bbbtable' => $bbbtable,

            'bbbselect' => $bbbselect,

            'bbbfrom' => $bbbfrom,

            'subplugintables' => $subplugintables,

            'subpluginselects' => $subpluginselects,

            'subpluginfroms' => $subpluginfroms

        ] = self::get_tables_info();

        $select = implode(', ', array_merge([$courseselect, $bbbselect, $cmselect], $subpluginselects));

        $subpluginsleftjoins = '';

        foreach ($subpluginfroms as $tablealias => $subpluginfrom) {

            $subpluginsleftjoins .= "LEFT JOIN {$subpluginfrom} ON bbb.id = {$tablealias}.bigbluebuttonbnid\n";

        }

        $params = [

            'modname' => 'bigbluebuttonbn',

            'bbbid' => $id,

        ];

        $where = 'bbb.id = :bbbid';

        $from = <<<EOF

                {$bbbfrom}

                INNER JOIN {$cmfrom} ON cm.instance = bbb.id

                INNER JOIN {$coursefrom} ON c.id = cm.course

                INNER JOIN {modules} m ON m.id = cm.module AND m.name = :modname

EOF;

        if ($idtype == self::IDTYPE_CMID) {

            $params['cmid'] = $id;

            $where = 'cm.id = :cmid';

            $from = <<<EOF

                {$cmfrom}

                INNER JOIN {$coursefrom} ON c.id = cm.course

                INNER JOIN {modules} m ON m.id = cm.module AND m.name = :modname

                INNER JOIN {$bbbfrom} ON cm.instance = bbb.id

EOF;

        }

        $sql = "SELECT {$select} FROM {$from} {$subpluginsleftjoins} WHERE {$where}";

        $result = $DB->get_record_sql($sql, $params);

        if (empty($result)) {

            return null;

        }

        $course = $coursetable->extract_from_result($result);

        $instancedata = $bbbtable->extract_from_result($result);

        self::extract_plugin_table_info($instancedata, $result, $subplugintables);

        if ($idtype == self::IDTYPE_INSTANCEID) {

            $cmid = $result->cmid;

        } else {

            $cmid = $id;

        }

        return new self($cmid, $course, $instancedata);

    }

    /**

     * Get the instance information from a meetingid.

     *

     * If a group is specified in the meetingid then this will also be set.

     *

     * @param string $meetingid

     * @return null|self

     */

    public static function get_from_meetingid(string $meetingid): ?self {

        global $DB;

        // Here we try to manage cases where the meetingid was actually produced by the old plugin or we have actually

        // changed the identifiers for the instance.

        $matches = self::parse_meetingid($meetingid);

        $existinginstanceid = $DB->get_field('bigbluebuttonbn', 'id', ['meetingid' => $matches['meetingid']]);

        if (empty($existinginstanceid)) {

            debugging("The meeting id with ID ($meetingid) was not found in the bigbluebuttonbn table", DEBUG_DEVELOPER);

            $existinginstanceid = $matches['instanceid']; // We try to "guess" the meeting id from its instance id. We should

            // not really do that as this changes simply if we move the course elsewhere.

            debugging("Trying to get the instanceid from the meeting ID. This will soon be deprecated", DEBUG_DEVELOPER);

        }

        $instance = self::get_from_instanceid($existinginstanceid);

        // Check for the group if any.

        if ($instance && array_key_exists('groupid', $matches)) {

            $instance->set_group_id($matches['groupid']);

        }

        return $instance;

    }

    /**

     * Parse a meetingID for key data.

     *

     * @param string $meetingid

     * @return array

     * @throws \moodle_exception

     */

    public static function parse_meetingid(string $meetingid): array {

        $result = preg_match(

            '@(?P<meetingid>[^-]*)-(?P<courseid>[^-]*)-(?P<instanceid>\d+)(\[(?P<groupid>\d*)\])?@',

            $meetingid,

            $matches

        );

        if ($result !== 1) {

            throw new \moodle_exception("The supplied meeting id '{$meetingid}' is invalid found.");

        }

        return $matches;

    }

    /**

     * Get all instances in the specified course.

     *

     * @param int $courseid

     * @return self[]

     */

    public static function get_all_instances_in_course(int $courseid): array {

        global $DB;

        [

            'coursetable' => $coursetable,

            'courseselect' => $courseselect,

            'coursefrom' => $coursefrom,

            'cmfrom' => $cmfrom,

            'bbbtable' => $bbbtable,

            'bbbselect' => $bbbselect,

            'bbbfrom' => $bbbfrom,

            'subplugintables' => $subplugintables,

            'subpluginselects' => $subpluginselects,

            'subpluginfroms' => $subpluginfroms

        ] = self::get_tables_info();

        $selects = implode(', ', array_merge([$courseselect, $bbbselect], $subpluginselects));

        $subpluginsleftjoins = '';

        foreach ($subpluginfroms as $tablealias => $subpluginfrom) {

            $subpluginsleftjoins .= "LEFT JOIN {$subpluginfrom} ON bbb.id = {$tablealias}.bigbluebuttonbnid\n";

        }

        $sql = <<<EOF

    SELECT cm.id as cmid, {$selects}

      FROM {$cmfrom}

INNER JOIN {$coursefrom} ON c.id = cm.course

INNER JOIN {modules} m ON m.id = cm.module AND m.name = :modname

INNER JOIN {$bbbfrom} ON cm.instance = bbb.id

{$subpluginsleftjoins}

     WHERE cm.course = :courseid

EOF;

        $results = $DB->get_records_sql($sql, [

            'modname' => 'bigbluebuttonbn',

            'courseid' => $courseid,

        ]);

        $instances = [];

        foreach ($results as $result) {

            $course = $coursetable->extract_from_result($result);

            $instancedata = $bbbtable->extract_from_result($result);

            self::extract_plugin_table_info($instancedata, $result, $subplugintables);

            $instances[$result->cmid] = new self($result->cmid, $course, $instancedata);

        }

        return $instances;

    }

    /**

     * Helper method to extract result from subplugin tables.

     * @param object $instancedata instance data

     * @param object $result result from sql query

     * @param array $subplugintables array of subplugin tables

     */

    private static function extract_plugin_table_info(object &$instancedata, object $result, array $subplugintables) {

        foreach ($subplugintables as $subplugintable) {

            $subplugindata = (array) $subplugintable->extract_from_result($result);

            if (isset($subplugindata['id'])) {

                unset($subplugindata['id']); // Make sure that from the subplugin we don't conflict with the bigbluebutton id.

            }

            $instancedata = (object) array_merge($subplugindata, (array) $instancedata);

        }

    }

    /**

     * Get the additional tables returned from the subplugin.

     *

     * @return array

     */

    private static function get_tables_info(): array {

        $coursetable = new table('course', 'c', 'c');

        $courseselect = $coursetable->get_field_select();

        $coursefrom = $coursetable->get_from_sql();

        $cmtable = new table('course_modules', 'cm', 'cm');

        $cmselect = $cmtable->get_field_select();

        $cmfrom = $cmtable->get_from_sql();

        $bbbtable = new table('bigbluebuttonbn', 'bbb', 'b');

        $bbbselect = $bbbtable->get_field_select();

        $bbbfrom = $bbbtable->get_from_sql();

        // Look now for additional tables returned from the subplugin.

        $subpluginselects = [];

        $subpluginfroms = [];

        $subplugintables = [];

        $subplugintablesnames = extension::get_join_tables();

        foreach ($subplugintablesnames as $index => $subplugintablename) {

            $tablealias = 'ext'.$index;

            $subplugintable = new table($subplugintablename, $tablealias, 'ext'.$index);

            $subpluginselects[$tablealias] = $subplugintable->get_field_select();

            $subpluginfroms[$tablealias] = $subplugintable->get_from_sql();

            $subplugintables[$tablealias] = $subplugintable;

        }

        return compact(

            'coursetable', 'courseselect', 'coursefrom',

            'cmtable', 'cmselect', 'cmfrom',

            'bbbtable', 'bbbselect', 'bbbfrom',

            'subplugintables', 'subpluginselects', 'subpluginfroms',

        );

    }

    /**

     * Set the current group id of the activity.

     *

     * @param int $groupid

     */

    public function set_group_id(int $groupid): void {

        $this->groupid = $groupid;

    }

    /**

     * Get the current groupid if set.

     *

     * @return int

     */

    public function get_group_id(): int {

        return empty($this->groupid) ? 0 : $this->groupid;

    }

    /**

     * Check whether this instance is configured to use a group.

     *

     * @return bool

     */

    public function uses_groups(): bool {

        $groupmode = groups_get_activity_groupmode($this->get_cm());

        return $groupmode != NOGROUPS;

    }

    /**

     * Get the group name for the current group, if a group has been set.

     *

     * @return null|string

     */

    public function get_group_name(): ?string {

        $groupid = $this->get_group_id();

        if (!$this->uses_groups()) {

            return null;

        }

        if ($groupid == 0) {

            return get_string('allparticipants');

        }

        return format_string(groups_get_group_name($groupid), true, ['context' => $this->get_context()]);

    }

    /**

     * Get the course object for the instance.

     *

     * @return stdClass

     */

    public function get_course(): stdClass {

        return $this->course;

    }

    /**

     * Get the course id of the course that the instance is in.

     *

     * @return int

     */

    public function get_course_id(): int {

        return $this->course->id;

    }

    /**

     * Get the cm_info object for the instance.

     *

     * @return cm_info

     */

    public function get_cm(): cm_info {

        if ($this->cm === null) {

            // We do a sort of late binding here as if we call get_cm on a disabled module or in a call stack where

            // get_cm was already called, we will get an exception or infinite loop.

            $modinfo = get_fast_modinfo($this->course);

            $this->cm = $modinfo->get_cm($this->cmid);

        }

        return $this->cm;

    }

    /**

     * Get the id of the course module.

     *

     * @return int

     */

    public function get_cm_id(): int {

        return $this->cmid;

    }

    /**

     * Get the context.

     *

     * @return context_module

     */

    public function get_context(): context_module {

        if ($this->context === null) {

            $this->context = context_module::instance($this->get_cm()->id);

        }

        return $this->context;

    }

    /**

     * Get the context ID of the module context.

     *

     * @return int

     */

    public function get_context_id(): int {

        return $this->get_context()->id;

    }

    /**

     * Get the course context.

     *

     * @return context_course

     */

    public function get_course_context(): context_course {

        return $this->get_context()->get_course_context();

    }

    /**

     * Get the big blue button instance data.

     *

     * @return stdClass

     */

    public function get_instance_data(): stdClass {

        return $this->instancedata;

    }

    /**

     * Get the instance id.

     *

     * @return int

     */

    public function get_instance_id(): int {

        return $this->instancedata->id;

    }

    /**

     * Helper to get an instance var.

     *

     * @param string $name

     * @return mixed|null

     */

    public function get_instance_var(string $name) {

        $instance = $this->get_instance_data();

        if (property_exists($instance, $name)) {

            return $instance->{$name};

        }

        return null;

    }

    /**

     * Get the meeting id for this meeting.

     *

     * @param null|int $groupid

     * @return string

     */

    public function get_meeting_id(?int $groupid = null): string {

        $baseid = sprintf(

            '%s-%s-%s',

            $this->get_instance_var('meetingid'),

            $this->get_course_id(),

            $this->get_instance_var('id')

        );

        if ($groupid === null) {

            $groupid = $this->get_group_id();

        }

        return sprintf('%s[%s]', $baseid, $groupid);

    }

    /**

     * Get the name of the meeting, considering any group if set.

     *

     * @return string

     */

    public function get_meeting_name(): string {

        $meetingname = $this->get_instance_var('name');

        $groupname = $this->get_group_name();

        if ($groupname !== null) {

            $meetingname .= " ({$groupname})";

        }

        return $meetingname;

    }

    /**

     * Get the meeting description with the pluginfile URLs optionally rewritten.

     *

     * @param bool $rewritepluginfileurls

     * @return string

     */

    public function get_meeting_description(bool $rewritepluginfileurls = false): string {

        $description = $this->get_instance_var('intro');

        if ($rewritepluginfileurls) {

            $description = file_rewrite_pluginfile_urls(

                $description,

                'pluginfile.php',

                $this->get_context_id(),

                'mod_bigbluebuttonbn',

                'intro',

                null

            );

        }

        return $description;

    }

    /**

     * Get the meeting type if set.

     *

     * @return null|string

     */

    public function get_type(): ?string {

        return $this->get_instance_var('type');

    }

    /**

     * Whether this instance is includes both a room, and recordings.

     *

     * @return bool

     */

    public function is_type_room_and_recordings(): bool {

        return $this->get_type() == self::TYPE_ALL;

    }

    /**

     * Whether this instance is one that only includes a room.

     *

     * @return bool

     */

    public function is_type_room_only(): bool {

        return $this->get_type() == self::TYPE_ROOM_ONLY;

    }

    /**

     * Whether this instance is one that only includes recordings.

     *

     * @return bool

     */

    public function is_type_recordings_only(): bool {

        return $this->get_type() == self::TYPE_RECORDING_ONLY;

    }

    /**

     * Get the participant list for the session.

     *

     * @return array

     */

    public function get_participant_list(): array {

        if ($this->participantlist === null) {

            $this->participantlist = roles::get_participant_list(

                $this->get_instance_data(),

                $this->get_context()

            );

        }

        return $this->participantlist;

    }

    /**

     * Get the user.

     *

     * @return stdClass

     */

    public function get_user(): stdClass {

        global $USER;

        return $USER;

    }

    /**

     * Get the id of the user.

     *

     * @return int

     */

    public function get_user_id(): int {

        $user = $this->get_user();

        return $user->id ?? 0;

    }

    /**

     * Get the fullname of the current user.

     *

     * @return string

     */

    public function get_user_fullname(): string {

        $user = $this->get_user();

        return fullname($user);

    }

    /**

     * Whether the current user is an administrator.

     *

     * @return bool

     */

    public function is_admin(): bool {

        global $USER;

        return is_siteadmin($USER->id);

    }

    /**

     * Whether the user is a session moderator.

     *

     * @return bool

     */

    public function is_moderator(): bool {

        return roles::is_moderator(

            $this->get_context(),

            $this->get_participant_list()

        );

    }

    /**

     * Whether this user can join the conference.

     *

     * This checks the user right for access against capabilities and group membership

     *

     * @return bool

     */

    public function can_join(): bool {

        $groupid = $this->get_group_id();

        $context = $this->get_context();

        $inrightgroup =

            groups_group_visible($groupid, $this->get_course(), $this->get_cm());

        $hascapability = has_capability('moodle/category:manage', $context)

            || (has_capability('mod/bigbluebuttonbn:join', $context) && $inrightgroup);

        $canjoin = $this->get_type() != self::TYPE_RECORDING_ONLY && $hascapability; // Recording only cannot be joined ever.

        return $canjoin;

    }

    /**

     * Whether this user can manage recordings.

     *

     * @return bool

     */

    public function can_manage_recordings(): bool {

        // Note: This will include site administrators.

        // The has_capability() function returns truthy for admins unless otherwise directed.

        return has_capability('mod/bigbluebuttonbn:managerecordings', $this->get_context());

    }

    /**

     * Whether this user can publish/unpublish/protect/unprotect/delete recordings.

     *

     * @param string $action

     * @return bool

     */

    public function can_perform_on_recordings($action): bool {

        // Note: This will include site administrators.

        // The has_capability() function returns truthy for admins unless otherwise directed.

        return has_capability("mod/bigbluebuttonbn:{$action}recordings", $this->get_context());

    }

    /**

     * Get the configured user limit.

     *

     * @return int

     */

    public function get_user_limit(): int {

        if ((boolean) config::get('userlimit_editable')) {

            return intval($this->get_instance_var('userlimit'));

        }

        return intval((int) config::get('userlimit_default'));

    }

    /**

     * Check whether the user limit has been reached.

     *

     * @param int $currentusercount The user count to check

     * @return bool

     */

    public function has_user_limit_been_reached(int $currentusercount): bool {

        $userlimit = $this->get_user_limit();

        if (empty($userlimit)) {

            return false;

        }

        return $currentusercount >= $userlimit;

    }

    /**

     * Check whether the current user counts towards the user limit.

     *

     * @return bool

     */

    public function does_current_user_count_towards_user_limit(): bool {

        if ($this->is_admin()) {

            return false;

        }

        if ($this->is_moderator()) {

            return false;

        }

        return true;

    }

    /**

     * Get the voice bridge details.

     *

     * @return null|int

     */

    public function get_voice_bridge(): ?int {

        $voicebridge = (int) $this->get_instance_var('voicebridge');

        if ($voicebridge > 0) {

            return 70000 + $voicebridge;

        }

        return null;

    }

    /**

     * Whether participants are muted on entry.

     *

     * @return bool

     */

    public function get_mute_on_start(): bool {

        return $this->get_instance_var('muteonstart');

    }

    /**

     * Get the moderator password.

     *

     * @return string

     */

    public function get_moderator_password(): string {

        return $this->get_instance_var('moderatorpass');

    }

    /**

     * Get the viewer password.

     *

     * @return string

     */

    public function get_viewer_password(): string {

        return $this->get_instance_var('viewerpass');

    }

    /**

     * Get the appropriate password for the current user.

     *

     * @return string

     */

    public function get_current_user_password(): string {

        if ($this->is_admin() || $this->is_moderator()) {

            return $this->get_moderator_password();

        }

        return $this->get_viewer_password();

    }

    /**

     * Get the appropriate designated role for the current user.

     *

     * @return string

     */

    public function get_current_user_role(): string {

        if ($this->is_admin() || $this->is_moderator()) {

            return 'MODERATOR';

        }

        return 'VIEWER';

    }

    /**

     * Whether to show the recording button

     *

     * @return bool

     */

    public function should_show_recording_button(): bool {

        global $CFG;

        if (!empty($CFG->bigbluebuttonbn_recording_hide_button_editable)) {

            $recordhidebutton = (bool) $this->get_instance_var('recordhidebutton');

            $recordallfromstart = (bool) $this->get_instance_var('recordallfromstart');

            return !($recordhidebutton || $recordallfromstart);

        }

        return !$CFG->bigbluebuttonbn_recording_hide_button_default;

    }

    /**

     * Whether this instance is recorded.

     *

     * @return bool

     */

    public function is_recorded(): bool {

        return (bool) $this->get_instance_var('record');

    }

    /**

     * Moderator approval required ?

     *

     * By default we leave it as false as "ALWAYS_ACCEPT" is the default value for

     * the guestPolicy create parameter (https://docs.bigbluebutton.org/dev/api.html)

     * @return bool

     */

    public function is_moderator_approval_required(): bool {

        return $this->get_instance_var('mustapproveuser') ?? false;

    }

    /**

     * Whether this instance can import recordings from another instance.

     *

     * @return bool

     */

    public function can_import_recordings(): bool {

        if (!config::get('importrecordings_enabled')) {

            return false;

        }

        if (!$this->can_manage_recordings()) {

            return false;

        }

        return $this->is_feature_enabled('importrecordings');

    }

    /**

     * Get recordings_imported from instancedata.

     *

     * @return bool

     */

    public function get_recordings_imported(): bool {

        if (config::get('recordings_imported_editable')) {

            return (bool) $this->get_instance_var('recordings_imported');

        }

        return config::get('recordings_imported_default');

    }

    /**

     * Whether this instance is recorded from the start.

     *

     * @return bool

     */

    public function should_record_from_start(): bool {

        if (!$this->is_recorded()) {

            // This meeting is not recorded.

            return false;

        }

        return (bool) $this->get_instance_var('recordallfromstart');

    }

    /**

     * Whether recording can be started and stopped.

     *

     * @return bool

     */

    public function allow_recording_start_stop(): bool {

        if (!$this->is_recorded()) {

            // If the meeting is not configured for recordings, do not allow it to be recorded.

            return false;

        }

        return $this->should_show_recording_button();

    }

    /**

     * Get the welcome message to display.

     *

     * @return string

     */

    public function get_welcome_message(): string {

        $welcomestring = $this->get_instance_var('welcome');

        if (!config::get('welcome_editable') || empty($welcomestring)) {

            $welcomestring = config::get('welcome_default');

        }

        if (empty($welcomestring)) {

            $welcomestring = get_string('mod_form_field_welcome_default', 'bigbluebuttonbn');

        }

        $welcome = [$welcomestring];

        if ($this->is_recorded()) {

            if ($this->should_record_from_start()) {

                $welcome[] = get_string('bbbrecordallfromstartwarning', 'bigbluebuttonbn');

            } else {

                $welcome[] = get_string('bbbrecordwarning', 'bigbluebuttonbn');

            }

        }

        return implode('<br><br>', $welcome);

    }

    /**

     * Get the presentation data for internal use.

     *

     * The URL returned for the presentation will be accessible through moodle with checks about user being logged in.

     *

     * @return array|null

     */

    public function get_presentation(): ?array {

        return $this->do_get_presentation_with_nonce(false);

    }

    /**

     * Get the presentation data for external API url.

     *

     * The URL returned for the presentation will be accessible publicly but once and with a specific URL.

     *

     * @return array|null

     */

    public function get_presentation_for_bigbluebutton_upload(): ?array {

        return $this->do_get_presentation_with_nonce(true);

    }

    /**

     * Generate Presentation URL.

     *

     * @param bool $withnonce The generated url will have a nonce included

     * @return array|null

     */

    protected function do_get_presentation_with_nonce(bool $withnonce): ?array {

        if ($this->has_ended()) {

            return files::get_presentation(

                $this->get_context(),

                $this->get_instance_var('presentation'),

                null,

                $withnonce

            );

        } else if ($this->is_currently_open()) {

            return files::get_presentation(

                $this->get_context(),

                $this->get_instance_var('presentation'),

                $this->get_instance_id(),

                $withnonce

            );

        } else {

            return [];

        }

    }