locallib.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/>.
/**
 * Theme Boost Campus - Locallib file
 *
 * @package   theme_boost_campus
 * @copyright 2017 Kathrin Osswald, Ulm University kathrin.osswald@uni-ulm.de
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

/**
 * Return the files from the loginbackgroundimage file area.
 * This function always loads the files from the filearea that is not really performant.
 * However, we accept this at the moment as it is only invoked on the login page.
 *
 * @return array|null
 * @throws coding_exception
 * @throws dml_exception
 */
function theme_boost_campus_get_loginbackgroundimage_files() {

    // Static variable to remember the files for subsequent calls of this function.
    static $files = null;

    if ($files == null) {
        // Get the system context.
        $systemcontext = \context_system::instance();

        // Get filearea.
        $fs = get_file_storage();

        // Get all files from filearea.
        $files = $fs->get_area_files($systemcontext->id, 'theme_boost_campus', 'loginbackgroundimage',
            false, 'itemid', false);
    }

    return $files;
}

/**
 * Get the random number for displaying the background image on the login page randomly.
 *
 * @return int|null
 * @throws coding_exception
 * @throws dml_exception
 */
function theme_boost_campus_get_random_loginbackgroundimage_number() {

    // Static variable.
    static $number = null;

    if ($number == null) {
        // Get all files for loginbackgroundimages.
        $files = theme_boost_campus_get_loginbackgroundimage_files();

        // Get count of array elements.
        $filecount = count($files);

        // We only return a number if images are uploaded to the loginbackgroundimage file area.
        if ($filecount > 0) {
            // Generate random number.
            $number = rand(1, $filecount);
        }
    }

    return $number;
}

/**
 * Get a random class for body tag for the background image of the login page.
 *
 * @return string
 */
function theme_boost_campus_get_random_loginbackgroundimage_class() {
    // Get the static random number.
    $number = theme_boost_campus_get_random_loginbackgroundimage_number();

    // Only create the class name with the random number if there is a number (=files uploaded to the file area).
    if ($number != null) {
        return "loginbackgroundimage" . $number;
    } else {
        return "";
    }
}

/**
 * Get the text that should be displayed for the randomly displayed background image on the login page.
 *
 * @return string
 * @throws coding_exception
 * @throws dml_exception
 */
function theme_boost_campus_get_loginbackgroundimage_text() {
    // Get the random number.
    $number = theme_boost_campus_get_random_loginbackgroundimage_number();

    // Only search for the text if there's a background image.
    if ($number != null) {

        // Get the files from the filearea loginbackgroundimage.
        $files = theme_boost_campus_get_loginbackgroundimage_files();
        // Get the file for the selected random number.
        $file = array_slice($files, ($number - 1), 1, false);
        // Get the filename.
        $filename = array_pop($file)->get_filename();

        // Get the config for loginbackgroundimagetext and make array out of the lines.
        $lines = explode("\n", get_config('theme_boost_campus', 'loginbackgroundimagetext'));

        // Proceed the lines.
        foreach ($lines as $line) {
            $settings = explode("|", $line);
            // Compare the filenames for a match and return the text that belongs to the randomly selected image.
            if (strcmp($filename, $settings[0]) == 0) {
                return format_string($settings[1]);
                break;
            }
        }
    } else {
        return "";
    }
}

/**
 * Add background images from setting 'loginbackgroundimage' to SCSS.
 *
 * @return string
 */
function theme_boost_campus_get_loginbackgroundimage_scss() {
    $count = 0;
    $scss = "";

    // Get all files from filearea.
    $files = theme_boost_campus_get_loginbackgroundimage_files();

    // Add URL of uploaded images to eviqualent class.
    foreach ($files as $file) {
        $count++;
        // Get url from file.
        $url = moodle_url::make_pluginfile_url($file->get_contextid(), $file->get_component(), $file->get_filearea(),
                $file->get_itemid(), $file->get_filepath(), $file->get_filename());
        // Add this url to the body class loginbackgroundimage[n] as a background image.
        $scss .= '$loginbackgroundimage' . $count.': "' . $url . '";';
    }

    return $scss;
}

/**
 * Create information needed for the imagearea.mustache file.
 *
 * @return array
 */
function theme_boost_campus_get_imageareacontent() {
    // Get cache.
    $themeboostcampuscache = cache::make('theme_boost_campus', 'imagearea');
    // If cache is filled, return the cache.
    $cachecontent = $themeboostcampuscache->get('imageareadata');
    if (!empty($cachecontent)) {
        return $cachecontent;
    } else { // Create cache.
        // Fetch context.
        $systemcontext = \context_system::instance();
        // Get filearea.
        $fs = get_file_storage();
        // Get all files from filearea.
        $files = $fs->get_area_files($systemcontext->id, 'theme_boost_campus', 'imageareaitems', false, 'itemid', false);

        // Initialize the array which holds the image links.
        $links = [];
        // Initialize the array which holds the alt texts.
        $alttexts = [];
        // Only continue processing if there are files in the filearea.
        if (!empty($files)) {
            // Get the content from the setting imageareaitemsattributes and explode it to an array by the delimiter "new line".
            // The string contains: the image identifier (uploaded file name) and the corresponding link URL.
            $lines = explode("\n", get_config('theme_boost_campus', 'imageareaitemsattributes'));
            // Parse item settings.
            foreach ($lines as $line) {
                $line = trim($line);
                // If the setting is empty.
                if (strlen($line) == 0) {
                    // Create an array with a dummy entry because the function array_key_exists need a
                    // not empty array for parameter 2.
                    $links = array('foo');
                    $alttexts = array('bar');
                    continue;
                } else {
                    $settings = explode("|", $line);
                    // Check if parameter 2 or 3 is set.
                    if (!empty($settings[1]) || !empty($settings[2])) {
                        foreach ($settings as $i => $setting) {
                            $setting = trim($setting);
                            if (!empty($setting)) {
                                switch ($i) {
                                    // Check for the first param: link.
                                    case 1:
                                        // The name of the image is the key for the URL that will be set.
                                        $links[$settings[0]] = $settings[1];
                                        break;
                                    // Check for the second param: alt text.
                                    case 2:
                                        // The name of the image is the key for the alt text that will be set.
                                        $alttexts[$settings[0]] = $settings[2];
                                        break;
                                }
                            }
                        }
                    }
                }
            }
            // Initialize the array which holds the data which is later stored in the cache.
            $imageareacache = [];
            // Traverse the files.
            foreach ($files as $file) {
                // Get the Moodle url for each file.
                $url = moodle_url::make_pluginfile_url($file->get_contextid(), $file->get_component(), $file->get_filearea(),
                        $file->get_itemid(), $file->get_filepath(), $file->get_filename());
                // Get the path to the file.
                $filepath = $url->get_path();
                // Get the filename.
                $filename = $file->get_filename();
                // If filename and link value from the imageareaitemsattributes setting entry match.
                if (array_key_exists($filename, $links)) {
                    $linkpath = $links[$filename];
                } else {
                    $linkpath = "";
                }
                // If filename and alt text value from the imageareaitemsattributes setting entry match.
                if (array_key_exists($filename, $alttexts)) {
                    $alttext = $alttexts[$filename];
                } else {
                    $alttext = "";
                }
                // Add the file.
                $imageareacache[] = array('filepath' => $filepath, 'linkpath' => $linkpath, 'alttext' => $alttext);
            }
            // Sort array alphabetically ascending to the key "filepath".
            usort($imageareacache, function($a, $b) {
                return strcmp($a["filepath"], $b["filepath"]);
            });
            // Fill the cache.
            $themeboostcampuscache->set('imageareadata', $imageareacache);
            return $imageareacache;
        } else { // If no images are uploaded, then cache an empty array.
            $themeboostcampuscache->set('imageareadata', array());
            return array();
        }
    }
}

/**
 * Returns a modified flat_navigation object.
 *
 * @param flat_navigation $flatnav The flat navigation object.
 * @return flat_navigation.
 */
function theme_boost_campus_process_flatnav(flat_navigation $flatnav) {
    global $USER;
    // If the setting defaulthomepageontop is enabled.
    if (get_config('theme_boost_campus', 'defaulthomepageontop') == 'yes') {
        // Only proceed processing if we are in a course context.
        if (($coursehomenode = $flatnav->find('coursehome', global_navigation::TYPE_CUSTOM)) != false) {
            // If the site home is set as the default homepage by the admin.
            if (get_config('core', 'defaulthomepage') == HOMEPAGE_SITE) {
                // Return the modified flat_navigation.
                $flatnavreturn = theme_boost_campus_set_node_on_top($flatnav, 'home', $coursehomenode);
            } else if (get_config('core', 'defaulthomepage') == HOMEPAGE_MY) { // If the dashboard is set as the default homepage
                // by the admin.
                // Return the modified flat_navigation.
                $flatnavreturn = theme_boost_campus_set_node_on_top($flatnav, 'myhome', $coursehomenode);
            } else if (get_config('core', 'defaulthomepage') == HOMEPAGE_USER) { // If the admin defined that the user can set
                // the default homepage for himself.
                // Site home.
                if (get_user_preferences('user_home_page_preference') == 0) {
                    // Return the modified flat_navigtation.
                    $flatnavreturn = theme_boost_campus_set_node_on_top($flatnav, 'home', $coursehomenode);
                } else if (get_user_preferences('user_home_page_preference') == 1 || // Dashboard.
                    get_user_preferences('user_home_page_preference') === false) { // If no user preference is set,
                    // use the default value of core setting default homepage (Dashboard).
                    // Return the modified flat_navigtation.
                    $flatnavreturn = theme_boost_campus_set_node_on_top($flatnav, 'myhome', $coursehomenode);
                } else { // Should not happen.
                    // Return the passed flat navigation without changes.
                    $flatnavreturn = $flatnav;
                }
            } else { // Should not happen.
                // Return the passed flat navigation without changes.
                $flatnavreturn = $flatnav;
            }
        } else { // Not in course context.
            // Return the passed flat navigation without changes.
            $flatnavreturn = $flatnav;
        }
    } else { // Defaulthomepageontop not enabled.
        // Return the passed flat navigation without changes.
        $flatnavreturn = $flatnav;
    }

    return $flatnavreturn;
}

/**
 * Modifies the flat_navigation to add the node on top.
 *
 * @param flat_navigation $flatnav The flat navigation object.
 * @param string $nodename The name of the node that is to modify.
 * @param navigation_node $beforenode The node before which the to be modified node shall be added.
 * @return flat_navigation.
 */
function theme_boost_campus_set_node_on_top(flat_navigation $flatnav, $nodename, $beforenode) {
    // Get the node for which the sorting shall be changed.
    $pageflatnav = $flatnav->find($nodename, global_navigation::TYPE_SYSTEM);

    // If user is logged in as a guest pageflatnav is false. Only proceed here if the result is true.
    if (!empty($pageflatnav)) {
        // Set the showdivider of the new top node to false that no empty nav-element will be created.
        $pageflatnav->set_showdivider(false);
        // Add the showdivider to the coursehome node as this is the next one and this will add a margin top to it.
        $beforenode->set_showdivider(true, $beforenode->text);
        // Remove the site home navigation node that it does not appear twice in the menu.
        $flatnav->remove($nodename);
        // Set the collection label for this node.
        $flatnav->set_collectionlabel($pageflatnav->text);
        // Add the saved site home node before the $beforenode.
        $flatnav->add($pageflatnav, $beforenode->key);
    }

    // Return the modified changes.
    return $flatnav;
}


/**
 * Provides the node for the in-course course or activity settings.
 *
 * @return navigation_node.
 */
function theme_boost_campus_get_incourse_settings() {
    global $COURSE, $PAGE;
    // Initialize the node with false to prevent problems on pages that do not have a courseadmin node.
    $node = false;
    // If setting showsettingsincourse is enabled.
    if (get_config('theme_boost_campus', 'showsettingsincourse') == 'yes') {
        // Only search for the courseadmin node if we are within a course or a module context.
        if ($PAGE->context->contextlevel == CONTEXT_COURSE || $PAGE->context->contextlevel == CONTEXT_MODULE) {
            // Get the courseadmin node for the current page.
            $node = $PAGE->settingsnav->find('courseadmin', navigation_node::TYPE_COURSE);
            // Check if $node is not empty for other pages like for example the langauge customization page.
            if (!empty($node)) {
                // If the setting 'incoursesettingsswitchtoroleposition' is set either set to the option 'yes'
                // or to the option 'both', then add these to the $node.
                if (((get_config('theme_boost_campus', 'incoursesettingsswitchtoroleposition') == 'yes') ||
                    (get_config('theme_boost_campus', 'incoursesettingsswitchtoroleposition') == 'both'))
                    && !is_role_switched($COURSE->id)) {
                    // Build switch role link
                    // We could only access the existing menu item by creating the user menu and traversing it.
                    // So we decided to create this node from scratch with the values copied from Moodle core.
                    $roles = get_switchable_roles($PAGE->context);
                    if (is_array($roles) && (count($roles) > 0)) {
                        // Define the properties for a new tab.
                        $properties = array('text' => get_string('switchroleto', 'theme_boost_campus'),
                                            'type' => navigation_node::TYPE_CONTAINER,
                                            'key'  => 'switchroletotab');
                        // Create the node.
                        $switchroletabnode = new navigation_node($properties);
                        // Add the tab to the course administration node.
                        $node->add_node($switchroletabnode);
                        // Add the available roles as children nodes to the tab content.
                        foreach ($roles as $key => $role) {
                            $properties = array('action' => new moodle_url('/course/switchrole.php',
                                array('id'         => $COURSE->id,
                                      'switchrole' => $key,
                                      'returnurl'  => $PAGE->url->out_as_local_url(false),
                                      'sesskey'    => sesskey())),
                                                'type'   => navigation_node::TYPE_CUSTOM,
                                                'text'   => $role);
                            $switchroletabnode->add_node(new navigation_node($properties));
                        }
                    }
                }
            }
        }
        return $node;
    }
}

/**
 * Provides the node for the in-course settings for other contexts.
 *
 * @return navigation_node.
 */
function theme_boost_campus_get_incourse_activity_settings() {
    global $PAGE;
    $context = $PAGE->context;
    $node = false;
    // If setting showsettingsincourse is enabled.
    if (get_config('theme_boost_campus', 'showsettingsincourse') == 'yes') {
        // Settings belonging to activity or resources.
        if ($context->contextlevel == CONTEXT_MODULE) {
            $node = $PAGE->settingsnav->find('modulesettings', navigation_node::TYPE_SETTING);
        } else if ($context->contextlevel == CONTEXT_COURSECAT) {
            // For course category context, show category settings menu, if we're on the course category page.
            if ($PAGE->pagetype === 'course-index-category') {
                $node = $PAGE->settingsnav->find('categorysettings', navigation_node::TYPE_CONTAINER);
            }
        } else {
            $node = false;
        }
    }
    return $node;
}

/**
 * Build the guest access hint HTML code.
 *
 * @param int $courseid The course ID.
 * @return string.
 */
function theme_boost_campus_get_course_guest_access_hint($courseid) {
    global $CFG;
    require_once($CFG->dirroot . '/enrol/self/lib.php');

    $html = '';
    $instances = enrol_get_instances($courseid, true);
    $plugins = enrol_get_plugins(true);
    foreach ($instances as $instance) {
        if (!isset($plugins[$instance->enrol])) {
            continue;
        }
        $plugin = $plugins[$instance->enrol];
        if ($plugin->show_enrolme_link($instance)) {
            $html = html_writer::tag('div', get_string('showhintcourseguestaccesslink',
                'theme_boost_campus', array('url' => $CFG->wwwroot . '/enrol/index.php?id=' . $courseid)));
            break;
        }
    }

    return $html;
}

/**
 * Return if the info banner should be displayed on current page layout.
 *
 * @param array $infobannerpagestoshow The list of page layouts on which the info banner should be shown.
 * @param string $infobannercontent The content which should be displayed within the info banner.
 * @param mixed|moodle_page $thispagelayout The current page layout.
 * @param string $perbibuserprefdialdismissed The user preference if the dissmissible banner has been dismissed.
 * @return boolean
 */
function theme_boost_campus_show_banner_on_selected_page($infobannerpagestoshow, $infobannercontent, $thispagelayout,
        $perbibuserprefdialdismissed) {

    // Initialize variable.
    $infobannershowonselectedpage = false;

    // Traverse multiselect setting.
    foreach ($infobannerpagestoshow as $page) {
        if (empty($infobannercontent)) {
            $infobannershowonselectedpage = false;
        } else {
            // Decide if the info banner should be shown at all.
            if (!empty($infobannercontent) && $thispagelayout == $page && !$perbibuserprefdialdismissed) {
                $infobannershowonselectedpage = true;
                continue;
            }
        }
    }
    return $infobannershowonselectedpage;
}

/**
 * Return if the time limited info banner should be displayed on current page layout.
 *
 * @param int $now The timestamp of the current server time.
 * @param array $timedibshowonpages The list of page layouts on which the info banner should be shown.
 * @param string $timedibcontent The content which should be displayed within the info banner.
 * @param string $timedibstartsetting The value from setting timedibstart.
 * @param string $timedibendsetting The value from setting timedibend.
 * @param mixed|moodle_page $thispagelayout The current page layout.
 * @return boolean
 */
function theme_boost_campus_show_timed_banner_on_selected_page($now, $timedibshowonpages, $timedibcontent, $timedibstartsetting,
        $timedibendsetting, $thispagelayout) {

    // Initialize variable.
    $timedinfobannershowonselectedpage = false;

    // Check if time settings are empty and try to convert the time string_s_ to a unix timestamp.
    if (empty($timedibstartsetting)) {
        $timedibstartempty = true;
        $timedibstart = 0;
    } else {
        $timedibstart = strtotime($timedibstartsetting);
        $timedibstartempty = false;
    }
    if (empty($timedibendsetting)) {
        $timedibendempty = true;
        $timedibend = 0;
    } else {
        $timedibend = strtotime($timedibendsetting);
        $timedibendempty = false;
    }

    // Add the time check:
    // Show the banner when now is between start and end time OR
    // Show the banner when start is not set but end is not reached yet OR
    // Show the banner when end is not set, but start lies in the past OR
    // Show the banner if no dates are set, so there's no time restriction.
    if (($now >= $timedibstart && $now <= $timedibend ||
            ($now <= $timedibend && $timedibstartempty) ||
            ($now >= $timedibstart && $timedibendempty) ||
            ($timedibstartempty && $timedibendempty))) {
        $timedinfobannershowonselectedpage = theme_boost_campus_show_banner_on_selected_page($timedibshowonpages,
                $timedibcontent, $thispagelayout, false);
    }

    return $timedinfobannershowonselectedpage;
}

/**
 * Build the course page information banners HTML code.
 * This function evaluates and composes all information banners which may appear on a course page below the full header.
 *
 * @return string.
 */
function theme_boost_campus_get_course_information_banners() {
    global $CFG, $COURSE, $PAGE, $USER;

    // Require user library.
    require_once($CFG->dirroot.'/user/lib.php');

    // Initialize HTML code.
    $html = '';

    // If the setting showhintcoursehidden is set, the visibility of the course is hidden and
    // a hint for the visibility will be shown.
    if (get_config('theme_boost_campus', 'showhintcoursehidden') == 'yes'
            && has_capability('theme/boost_campus:viewhintinhiddencourse', \context_course::instance($COURSE->id))
            && $PAGE->has_set_url()
            && $PAGE->url->compare(new moodle_url('/course/view.php'), URL_MATCH_BASE)
            && $COURSE->visible == false) {
        $html .= html_writer::start_tag('div', array('class' => 'course-hidden-infobox alert alert-warning'));
        $html .= html_writer::start_tag('div', array('class' => 'media'));
        $html .= html_writer::start_tag('div', array('class' => 'mr-3 icon-size-5'));
        $html .= html_writer::tag('i', null, array('class' => 'fa fa-exclamation-circle fa-3x'));
        $html .= html_writer::end_tag('div');
        $html .= html_writer::start_tag('div', array('class' => 'media-body align-self-center'));
        $html .= get_string('showhintcoursehiddengeneral', 'theme_boost_campus', $COURSE->id);
        // If the user has the capability to change the course settings, an additional link to the course settings is shown.
        if (has_capability('moodle/course:update', context_course::instance($COURSE->id))) {
            $html .= html_writer::tag('div', get_string('showhintcoursehiddensettingslink',
                    'theme_boost_campus', array('url' => $CFG->wwwroot.'/course/edit.php?id='. $COURSE->id)));
        }
        $html .= html_writer::end_tag('div');
        $html .= html_writer::end_tag('div');
        $html .= html_writer::end_tag('div');
    }

    // If the setting showhintcourseguestaccess is set, a hint for users that view the course with guest access is shown.
    // We also check that the user did not switch the role. This is a special case for roles that can fully access the course
    // without being enrolled. A role switch would show the guest access hint additionally in that case and this is not
    // intended.
    if (get_config('theme_boost_campus', 'showhintcourseguestaccess') == 'yes'
            && is_guest(\context_course::instance($COURSE->id), $USER->id)
            && $PAGE->has_set_url()
            && $PAGE->url->compare(new moodle_url('/course/view.php'), URL_MATCH_BASE)
            && !is_role_switched($COURSE->id)) {
        $html .= html_writer::start_tag('div', array('class' => 'course-guestaccess-infobox alert alert-warning'));
        $html .= html_writer::start_tag('div', array('class' => 'media'));
        $html .= html_writer::start_tag('div', array('class' => 'mr-3 icon-size-5'));
        $html .= html_writer::tag('i', null, array('class' => 'fa fa-exclamation-circle fa-3x'));
        $html .= html_writer::end_tag('div');
        $html .= html_writer::start_tag('div', array('class' => 'media-body align-self-center'));
        $html .= get_string('showhintcourseguestaccessgeneral', 'theme_boost_campus',
                array('role' => role_get_name(get_guest_role())));
        $html .= theme_boost_campus_get_course_guest_access_hint($COURSE->id);
        $html .= html_writer::end_tag('div');
        $html .= html_writer::end_tag('div');
        $html .= html_writer::end_tag('div');
    }

    // If the setting showhintcourseselfenrol is set, a hint for users is shown that the course allows unrestricted self
    // enrolment. This hint is only shown if the course is visible, the self enrolment is visible and if the user has the
    // capability "theme/boost_campus:viewhintcourseselfenrol".
    if (get_config('theme_boost_campus', 'showhintcourseselfenrol') == 'yes'
            && has_capability('theme/boost_campus:viewhintcourseselfenrol', \context_course::instance($COURSE->id))
            && $PAGE->has_set_url()
            && $PAGE->url->compare(new moodle_url('/course/view.php'), URL_MATCH_BASE)
            && $COURSE->visible == true) {
        // Get the active enrol instances for this course.
        $enrolinstances = enrol_get_instances($COURSE->id, true);
        // Prepare to remember when self enrolment is / will be possible.
        $selfenrolmentpossiblecurrently = false;
        $selfenrolmentpossiblefuture = false;
        foreach ($enrolinstances as $instance) {
            // Check if unrestricted self enrolment is possible currently or in the future.
            $now = (new \DateTime("now", \core_date::get_server_timezone_object()))->getTimestamp();
            if ($instance->enrol == 'self' && empty($instance->password) && $instance->customint6 == 1 &&
                    (empty($instance->enrolenddate) || $instance->enrolenddate > $now)) {

                // Build enrol instance object with all necessary information for rendering the note later.
                $instanceobject = new stdClass();

                // Remember instance name.
                if (empty($instance->name)) {
                    $instanceobject->name = get_string('pluginname', 'enrol_self') .
                            " (" . get_string('defaultcoursestudent', 'core') . ")";
                } else {
                    $instanceobject->name = $instance->name;
                }

                // Remember type of unrestrictedness.
                if (empty($instance->enrolenddate) && empty($instance->enrolstartdate)) {
                    $instanceobject->unrestrictedness = 'unlimited';
                    $selfenrolmentpossiblecurrently = true;
                } else if (empty($instance->enrolstartdate) &&
                        !empty($instance->enrolenddate) && $instance->enrolenddate > $now) {
                    $instanceobject->unrestrictedness = 'until';
                    $selfenrolmentpossiblecurrently = true;
                } else if (empty($instance->enrolenddate) &&
                        !empty($instance->enrolstartdate) && $instance->enrolstartdate > $now) {
                    $instanceobject->unrestrictedness = 'from';
                    $selfenrolmentpossiblefuture = true;
                } else if (empty($instance->enrolenddate) &&
                        !empty($instance->enrolstartdate) && $instance->enrolstartdate <= $now) {
                    $instanceobject->unrestrictedness = 'since';
                    $selfenrolmentpossiblecurrently = true;
                } else if (!empty($instance->enrolstartdate) && $instance->enrolstartdate > $now &&
                        !empty($instance->enrolenddate) && $instance->enrolenddate > $now) {
                    $instanceobject->unrestrictedness = 'fromuntil';
                    $selfenrolmentpossiblefuture = true;
                } else if (!empty($instance->enrolstartdate) && $instance->enrolstartdate <= $now &&
                        !empty($instance->enrolenddate) && $instance->enrolenddate > $now) {
                    $instanceobject->unrestrictedness = 'sinceuntil';
                    $selfenrolmentpossiblecurrently = true;
                } else {
                    // This should not happen, thus continue to next instance.
                    continue;
                }

                // Remember enrol start date.
                if (!empty($instance->enrolstartdate)) {
                    $instanceobject->startdate = $instance->enrolstartdate;
                } else {
                    $instanceobject->startdate = null;
                }

                // Remember enrol end date.
                if (!empty($instance->enrolenddate)) {
                    $instanceobject->enddate = $instance->enrolenddate;
                } else {
                    $instanceobject->enddate = null;
                }

                // Remember this instance.
                $selfenrolinstances[$instance->id] = $instanceobject;
            }
        }

        // If there is at least one unrestricted enrolment instance,
        // show the hint with information about each unrestricted active self enrolment in the course.
        if (!empty($selfenrolinstances) &&
                ($selfenrolmentpossiblecurrently == true || $selfenrolmentpossiblefuture == true)) {
            // Start hint box.
            $html .= html_writer::start_tag('div', array('class' => 'course-selfenrol-infobox alert alert-info'));
            $html .= html_writer::start_tag('div', array('class' => 'media'));
            $html .= html_writer::start_tag('div', array('class' => 'mr-3 icon-size-5'));
            $html .= html_writer::tag('i', null, array('class' => 'fa fa-sign-in fa-3x'));
            $html .= html_writer::end_tag('div');
            $html .= html_writer::start_tag('div', array('class' => 'media-body align-self-center'));

            // Show the start of the hint depending on the fact if enrolment is already possible currently or
            // will be in the future.
            if ($selfenrolmentpossiblecurrently == true) {
                $html .= get_string('showhintcourseselfenrolstartcurrently', 'theme_boost_campus');
            } else if ($selfenrolmentpossiblefuture == true) {
                $html .= get_string('showhintcourseselfenrolstartfuture', 'theme_boost_campus');
            }
            $html .= html_writer::empty_tag('br');

            // Iterate over all enrolment instances to output the details.
            foreach ($selfenrolinstances as $selfenrolinstanceid => $selfenrolinstanceobject) {
                // If the user has the capability to config self enrolments, enrich the instance name with the settings link.
                if (has_capability('enrol/self:config', \context_course::instance($COURSE->id))) {
                    $url = new moodle_url('/enrol/editinstance.php', array('courseid' => $COURSE->id,
                            'id' => $selfenrolinstanceid, 'type' => 'self'));
                    $selfenrolinstanceobject->name = html_writer::link($url, $selfenrolinstanceobject->name);
                }

                // Show the enrolment instance information depending on the instance configuration.
                if ($selfenrolinstanceobject->unrestrictedness == 'unlimited') {
                    $html .= get_string('showhintcourseselfenrolunlimited', 'theme_boost_campus',
                            array('name' => $selfenrolinstanceobject->name));
                } else if ($selfenrolinstanceobject->unrestrictedness == 'until') {
                    $html .= get_string('showhintcourseselfenroluntil', 'theme_boost_campus',
                            array('name' => $selfenrolinstanceobject->name,
                                    'until' => userdate($selfenrolinstanceobject->enddate)));
                } else if ($selfenrolinstanceobject->unrestrictedness == 'from') {
                    $html .= get_string('showhintcourseselfenrolfrom', 'theme_boost_campus',
                            array('name' => $selfenrolinstanceobject->name,
                                    'from' => userdate($selfenrolinstanceobject->startdate)));
                } else if ($selfenrolinstanceobject->unrestrictedness == 'since') {
                    $html .= get_string('showhintcourseselfenrolsince', 'theme_boost_campus',
                            array('name' => $selfenrolinstanceobject->name,
                                    'since' => userdate($selfenrolinstanceobject->startdate)));
                } else if ($selfenrolinstanceobject->unrestrictedness == 'fromuntil') {
                    $html .= get_string('showhintcourseselfenrolfromuntil', 'theme_boost_campus',
                            array('name' => $selfenrolinstanceobject->name,
                                    'until' => userdate($selfenrolinstanceobject->enddate),
                                    'from' => userdate($selfenrolinstanceobject->startdate)));
                } else if ($selfenrolinstanceobject->unrestrictedness == 'sinceuntil') {
                    $html .= get_string('showhintcourseselfenrolsinceuntil', 'theme_boost_campus',
                            array('name' => $selfenrolinstanceobject->name,
                                    'until' => userdate($selfenrolinstanceobject->enddate),
                                    'since' => userdate($selfenrolinstanceobject->startdate)));
                }

                // Add a trailing space to separate this instance from the next one.
                $html .= ' ';
            }

            // If the user has the capability to config self enrolments, add the call for action.
            if (has_capability('enrol/self:config', \context_course::instance($COURSE->id))) {
                $html .= html_writer::empty_tag('br');
                $html .= get_string('showhintcourseselfenrolinstancecallforaction', 'theme_boost_campus');
            }

            // End hint box.
            $html .= html_writer::end_tag('div');
            $html .= html_writer::end_tag('div');
            $html .= html_writer::end_tag('div');
        }
    }

    // Only use this if setting 'showswitchedroleincourse' is active.
    if (get_config('theme_boost_campus', 'showswitchedroleincourse') === 'yes') {
        // Check if the user did a role switch.
        // If not, adding this section would make no sense and, even worse,
        // user_get_user_navigation_info() will throw an exception due to the missing user object.
        if (is_role_switched($COURSE->id)) {
            // Get the role name switched to.
            $opts = \user_get_user_navigation_info($USER, $PAGE);
            $role = $opts->metadata['rolename'];
            // Get the URL to switch back (normal role).
            $url = new moodle_url('/course/switchrole.php',
                    array('id'        => $COURSE->id, 'sesskey' => sesskey(), 'switchrole' => 0,
                            'returnurl' => $PAGE->url->out_as_local_url(false)));
            $html .= html_writer::start_tag('div', array('class' => 'switched-role-infobox alert alert-info'));
            $html .= html_writer::start_tag('div', array('class' => 'media'));
            $html .= html_writer::start_tag('div', array('class' => 'mr-3 icon-size-5'));
            $html .= html_writer::tag('i', null, array('class' => 'fa fa-user-circle fa-3x'));
            $html .= html_writer::end_tag('div');
            $html .= html_writer::start_tag('div', array('class' => 'media-body align-self-center'));
            $html .= html_writer::start_tag('div');
            $html .= get_string('switchedroleto', 'theme_boost_campus');
            // Give this a span to be able to address via CSS.
            $html .= html_writer::tag('span', $role, array('class' => 'switched-role'));
            $html .= html_writer::end_tag('div');
            // Return to normal role link.
            $html .= html_writer::start_tag('div');
            $html .= html_writer::tag('a', get_string('switchrolereturn', 'core'),
                    array('class' => 'switched-role-backlink', 'href' => $url));
            $html .= html_writer::end_tag('div'); // Return to normal role link: end div.
            $html .= html_writer::end_tag('div');
            $html .= html_writer::end_tag('div');
            $html .= html_writer::end_tag('div');
        }
    }

    // Return HTML code.
    return $html;
}