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/>.

/**

 * file contains the general utility class for this tool

 *

 * File         util.php

 * Encoding     UTF-8

 * @copyright   Sebsoft.nl

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

 */

namespace tool_usersuspension;

use tool_usersuspension\statustable;

/**

 * tool_usersuspension\util

 *

 * @package     tool_usersuspension

 *

 * @copyright   Sebsoft.nl

 * @author      R.J. van Dongen <rogier@sebsoft.nl>

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

 */

class util {

    /**

     * __construct() DO NOT SHOW / ALLOW TO BE CALLED: Open source version

     */

    private function __construct() {

        // Open source version.

    }

    /**

     * Nasty function to try and assure UNIQUE prefixes.

     * Only use this to prefix named query params.

     *

     * @return string

     */

    public static function get_prefix() {

        static $counter = 0;

        $counter++;

        return 'pfx' . $counter;

    }

    /**

     * Return a more humanly readable timespan string from a timespan

     *

     * @param float $size

     * @return string

     */

    final public static function format_timespan($size) {

        $neg = ($size < 0);

        $size = (float) abs($size);

        if ($size > 7 * 86400) {

            return ($neg ? '-' : '') . sprintf('%d %s', floor($size / (7 * 86400)), get_string('weeks'));

        } else if ($size > 86400) {

            return ($neg ? '-' : '') . sprintf('%d %s', floor($size / 86400), get_string('days'));

        } else if ($size > 3600) {

            return ($neg ? '-' : '') . sprintf('%d %s', floor($size / 3600), get_string('hours'));

        } else if ($size > 60) {

            return ($neg ? '-' : '') . sprintf('%d %s', floor($size / 60), get_string('minutes'));

        } else {

            return ($neg ? '-' : '') . sprintf('%d %s', $size, get_string('seconds'));

        }

    }

    /**

     * Count the number of activly monitored users.

     * Do note this method will not count users configured to be excluded.

     *

     * @return int number of actively monitored users

     */

    public static function count_monitored_users() {

        global $DB;

        $where = 'deleted = :deleted';

        $params = array('deleted' => 0);

        static::append_user_exclusion($where, $params, 'u.');

        return $DB->count_records_sql('SELECT COUNT(*) FROM {user} u WHERE ' . $where, $params);

    }

    /**

     * Count the number of suspended users.

     * Do note this method will not count users configured to be excluded.

     *

     * @return int number of suspended users

     */

    public static function count_suspended_users() {

        global $DB;

        $where = 'suspended = :suspended AND deleted = :deleted';

        $params = array('suspended' => 1, 'deleted' => 0);

        static::append_user_exclusion($where, $params, 'u.');

        return $DB->count_records_sql('SELECT COUNT(*) FROM {user} u WHERE ' . $where, $params);

    }

    /**

     * Count the number of users that are to be suspended.

     * Do note this method will not count users configured to be excluded.

     *

     * @return int number of suspendable users

     */

    public static function count_users_to_suspend() {

        global $DB;

        list($where, $params) = static::get_suspension_query(false);

        list($where2, $params2) = static::get_suspension_query(true);

        $sql = 'SELECT COUNT(*) FROM {user} u WHERE ' . "({$where}) OR ({$where2})";

        return $DB->count_records_sql($sql, $params + $params2);

    }

    /**

     * Count the number of users that are to be deleted.

     * Do note this method will not count users configured to be excluded.

     *

     * @return int number of deleteable users

     */

    public static function count_users_to_delete() {

        global $DB;

        list($where, $params) = static::get_deletion_query(false);

        list($where2, $params2) = static::get_deletion_query(true);

        $sql = 'SELECT COUNT(*) FROM {user} u WHERE ' . "({$where}) OR ({$where2})";

        return $DB->count_records_sql($sql, $params + $params2);

    }

    /**

     * Marks inactive users as suspended according to configuration settings.

     *

     * @return boolean

     */

    final public static function mark_users_to_suspend() {

        global $DB;

        if (!(bool)config::get('enabled')) {

            return false;

        }

        if (!(bool)config::get('enablesmartdetect')) {

            return false;

        }

        $lastrun = static::get_lastrun_config('smartdetect', 0, true);

        $deltatime = time() - $lastrun;

        if ($deltatime < config::get('smartdetect_interval')) {

            return false;

        }

        list($where, $params) = static::get_suspension_query(true);

        $sql = "SELECT * FROM {user} u WHERE $where";

        $users = $DB->get_records_sql($sql, $params);

        foreach ($users as $user) {

            // Suspend user here.

            static::do_suspend_user($user);

        }

    }

    /**

     * Warns inactive users that they will be suspended soon. This must be run *AFTER* user suspension is done,

     * or it will email suspended users if this is the first run.

     */

    final public static function warn_users_of_suspension() {

        global $DB;

        if (!(bool)config::get('enabled')) {

            return false;

        }

        if (!(bool)config::get('enablesmartdetect')) {

            return false;

        }

        if (!(bool)config::get('enablesmartdetect_warning')) {

            return false;

        }

        // Run in parallel with the suspensions.

        $lastrun = static::get_lastrun_config('smartdetect', 0, true);

        $deltatime = time() - $lastrun;

        if ($deltatime < config::get('smartdetect_interval')) {

            return false;

        }

        // Do nothing if warningtime is 0.

        $warningtime = (int)config::get('smartdetect_warninginterval');

        if ($warningtime <= 0) {

            return false;

        }

        // Get the query for users to warn.

        $warningthreshold = (time() - (int)config::get('smartdetect_suspendafter')) + $warningtime;

        list($where, $params) = static::get_suspension_query(true, $warningthreshold);

        $sql = "SELECT * FROM {user} u WHERE $where";

        $users = $DB->get_records_sql($sql, $params);

        foreach ($users as $user) {

            // Check whether the user was already warned.

            if ((get_user_preferences('tool_usersuspension_warned', false, $user))) {

                continue;

            }

            static::process_user_warning_email($user);

            // Mark the user as warned. This will be reset on their first successful login post warning.

            set_user_preference('tool_usersuspension_warned', true, $user);

        }

    }

    /**

     * Deletes suspended users according to configuration settings.

     *

     * @return boolean

     */

    final public static function delete_suspended_users() {

        global $DB;

        if (!(bool)config::get('enabled')) {

            return false;

        }

        if (!(bool)config::get('enablecleanup')) {

            return false;

        }

        $lastrun = static::get_lastrun_config('cleanup', 0, true);

        $deltatime = time() - $lastrun;

        if ($deltatime < config::get('cleanup_interval')) {

            return false;

        }

        list($where, $params) = static::get_deletion_query(true);

        $sql = "SELECT * FROM {user} u WHERE $where";

        $users = $DB->get_records_sql($sql, $params);

        foreach ($users as $user) {

            // Delete user here.

            static::do_delete_user($user);

        }

    }

    /**

     * Gets last run configuration for a specific type

     *

     * @param string $type

     * @param mixed $default default value to return if this config is not set

     * @param bool $autosetnew if true, automatically insert current time for the last run configuration

     */

    final protected static function get_lastrun_config($type, $default = null, $autosetnew = true) {

        $value = get_config('tool_usersuspension', $type . '_lastrun');

        if ($autosetnew) {

            static::set_lastrun_config($type);

        }

        return (($value === false) ? $default : $value);

    }

    /**

     * Sets last run configuration for a specific type

     *

     * @param string $type

     */

    final protected static function set_lastrun_config($type) {

        set_config($type . '_lastrun', time(), 'tool_usersuspension');

    }

    /**

     * Performs the actual user suspension by updating the users table

     *

     * @param \stdClass $user

     * @param bool $automated true if a result of automated suspension, false if suspending

     *              is a result of a manual action

     */

    final public static function do_suspend_user($user, $automated = true) {

        global $USER, $CFG;

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

        // Piece of code taken from /admin/user.php so we dance just like moodle does.

        if (!is_siteadmin($user) && $USER->id != $user->id && $user->suspended != 1) {

            $user->suspended = 1;

            // Force logout.

            \core\session\manager::kill_user_sessions($user->id);

            user_update_user($user, false, true);

            // Process email if applicable.

            $user->suspended = 0; // This is to prevent mail from not sending.

            $emailsent = (static::process_user_suspended_email($user, $automated) === true);

            // Create status record.

            static::process_status_record($user, 'suspended', $emailsent);

            // Trigger event.

            $event = event\user_suspended::create(

                    array(

                        'objectid' => $user->id,

                        'relateduserid' => $user->id,

                        'context' => \context_user::instance($user->id),

                        'other' => array()

                        )

                    );

            $event->trigger();

            return true;

        }

        return false;

    }

    /**

     * Performs the actual user unsuspension by updating the users table

     *

     * @param \stdClass $user

     */

    final public static function do_unsuspend_user($user) {

        global $CFG, $DB;

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

        // Piece of code taken from /admin/user.php so we dance just like moodle does.

        if ($user = $DB->get_record('user', array('id' => $user->id,

                'mnethostid' => $CFG->mnet_localhost_id, 'deleted' => 0))) {

            if ($user->suspended != 0) {

                $user->suspended = 0;

                user_update_user($user, false, true);

                // Process email id applicable.

                $emailsent = (static::process_user_unsuspended_email($user) === true);

                // Trigger event.

                $event = event\user_unsuspended::create(

                        array(

                            'objectid' => $user->id,

                            'relateduserid' => $user->id,

                            'context' => \context_user::instance($user->id),

                            'other' => array()

                            )

                        );

                $event->trigger();

                // Create status record.

                static::process_status_record($user, 'unsuspended', $emailsent);

                return true;

            }

        }

        return false;

    }

    /**

     * Performs the actual user deletion

     *

     * @param \stdClass $user

     * @return bool true if successful, false otherwise

     */

    final public static function do_delete_user($user) {

        global $USER, $CFG;

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

        // Piece of code taken from /admin/user.php so we dance just like moodle does.

        if (!is_siteadmin($user) && $USER->id != $user->id && $user->deleted != 1) {

            // Force logout.

            \core\session\manager::kill_user_sessions($user->id);

            user_delete_user($user);

            // Process email id applicable.

            $user->suspended = 0; // This is to prevent mail from not sending.

            $emailsent = (static::process_user_deleted_email($user) === true);

            // Create status record.

            static::process_status_record($user, 'deleted', $emailsent);

            return true;

        }

        return false;

    }

    /**

     * Process a status record.

     * This will insert a new status record and move all existing status records for the given user to the logs.

     *

     * @param \stdClass $user user record

     * @param string $status status string

     * @param bool $emailsent whether or not the email was sent

     */

    final public static function process_status_record($user, $status, $emailsent) {

        global $DB;

        // Move existing record to log.

        $recordstolog = $DB->get_records('tool_usersuspension_status', array('userid' => $user->id));

        foreach ($recordstolog as $record) {

            unset($record->id);

            $DB->insert_record('tool_usersuspension_log', $record);

        }

        $DB->delete_records('tool_usersuspension_status', array('userid' => $user->id));

        // Insert new record.

        $statusrecord = (object) array(

            'userid' => $user->id,

            'status' => $status,

            'mailsent' => ($emailsent ? 1 : 0),

            'mailedto' => $user->email,

            'timecreated' => time()

        );

        $DB->insert_record('tool_usersuspension_status', $statusrecord);

    }

    /**

     * Add user exclusion to the query.

     * This will, at the very least, exclude the site administrators and the guest account

     *

     * @param string $where

     * @param array $params

     * @param string $useraliasprefix alias prefix for users (e.g. 'u.' to indicate u.id)

     */

    public static function append_user_exclusion(&$where, &$params, $useraliasprefix = '') {

        global $CFG, $DB;

        // Set standard exclusions.

        $excludeids = array(1, $CFG->siteguest); // Guest account.

        $excludeids = array_merge($excludeids, array_keys(get_admins()));

        // Now append configured exclusions.

        $excludeids = array_merge($excludeids, static::get_user_exclusion_list());

        $excludeids = array_unique($excludeids);

        list($notinsql, $uparams) = $DB->get_in_or_equal($excludeids, SQL_PARAMS_NAMED, 'uidexc', false, 0);

        $where .= ' AND ' . $useraliasprefix . 'id '.$notinsql;

        $params = $params + $uparams;

    }

    /**

     * Get a list of userids to exclude.

     * This will load all relevant userids from the tool's exclusion table

     *

     * @return array list of user ids

     */

    public static function get_user_exclusion_list() {

        global $DB;

        // First load users.

        $userids = $DB->get_fieldset_select('tool_usersuspension_excl', 'refid',

                'type = :type', array('type' => 'user'));

        $cohortids = $DB->get_fieldset_select('tool_usersuspension_excl', 'refid',

                'type = :type', array('type' => 'cohort'));

        foreach ($cohortids as $cohortid) {

            $cohortuserids = $DB->get_fieldset_select('cohort_members', 'userid',

                    'cohortid = :cohid', array('cohid' => $cohortid));

            $userids = array_merge($userids, $cohortuserids);

        }

        return array_unique($userids);

    }

    /**

     * Return the query to load users applicable for suspension.

     *

     * @param bool $pastsuspensiondate if true, this return the query for users

     *          that are past their date of suspension (i.e. should be suspended).

     *          If false, this returns the query for users that are not past their

     *          date of suspension yet. The latter can be used for statistics on

     *          when users would get suspended.

     * @param int $customtime A custom timestamp to perform the comparison against.

     * @return array A list containing the constructed where part of the sql and an array of parameters.

     */

    public static function get_suspension_query($pastsuspensiondate = true, $customtime = null) {

        global $CFG;

        $uniqid = static::get_prefix();

        $detectoperator = $pastsuspensiondate ? '<' : '>';

        $timecheck = !empty($customtime) ? $customtime : time() - (config::get('smartdetect_suspendafter'));

        $where = "u.confirmed = 1 AND u.suspended = 0 AND u.deleted = 0 AND u.mnethostid = :{$uniqid}mnethost ";

        $where .= "AND (";

        $where .= "(u.lastaccess = 0 AND u.firstaccess > 0 AND u.firstaccess $detectoperator :{$uniqid}time1)";

        $where .= " OR (u.lastaccess > 0 AND u.lastaccess $detectoperator :{$uniqid}time2)";

        $where .= " OR (u.auth = 'manual' AND u.firstaccess = 0 AND u.lastaccess = 0 ";

        $where .= "     AND u.timemodified > 0 AND u.timemodified $detectoperator :{$uniqid}time3)";

        $where .= ")";

        $params = array("{$uniqid}mnethost" => $CFG->mnet_localhost_id,

            "{$uniqid}time1" => $timecheck,

            "{$uniqid}time2" => $timecheck,

            "{$uniqid}time3" => $timecheck);

        // Append user exclusion.

        static::append_user_exclusion($where, $params, 'u.');

        return array($where, $params);

    }

    /**

     * Return the query to load users applicable for deletion.

     *

     * @param bool $pastdeletiondate if true, this return the query for users

     *          that are past their date of deletion (i.e. should be deleted).

     *          If false, this returns the query for users that are not past their

     *          date of deletion yet. The latter can be used for statistics on

     *          when users would get deleted.

     * @return array A list containing the constructed where part of the sql and an array of parameters.

     */

    public static function get_deletion_query($pastdeletiondate = true) {

        global $CFG;

        $detectoperator = $pastdeletiondate ? '<' : '>';

        $uniqid = static::get_prefix();

        $params = array("{$uniqid}mnethost" => $CFG->mnet_localhost_id,

            "{$uniqid}" => time() - (int)config::get('cleanup_deleteafter'));

        $where = "u.suspended = 1 AND u.confirmed = 1 AND u.deleted = 0 "

                . "AND u.mnethostid = :{$uniqid}mnethost AND u.timemodified $detectoperator :{$uniqid}";

        static::append_user_exclusion($where, $params, 'u.');

        return array($where, $params);

    }

    /**

     * Process the view for cohort exclusion.

     * This will display or process the exclusion form for cohort exclusion.

     *

     * @param \moodle_url $url

     */

    public static function view_process_cohort_exclusion($url) {

        global $CFG, $OUTPUT;

        require_once($CFG->dirroot . '/' . $CFG->admin . '/tool/usersuspension/classes/forms/exclude/cohort.php');

        $formurl = clone $url;

        $formurl->param('action', 'add');

        $formurl->param('addtype', 'cohort');

        $mform = new forms\exclude\cohort($formurl);

        if ($mform->is_cancelled()) {

            redirect($url);

        } else if ($data = $mform->get_data()) {

            echo $OUTPUT->header();

            echo '<div id="tool-usersuspension-form-container">';

            $mform->process();

            echo '<br/>';

            echo static::continue_button($url, get_string('button:backtoexclusions', 'tool_usersuspension'));

            echo '</div>';

            echo $OUTPUT->footer();

        } else {

            echo $OUTPUT->header();

            echo '<div id="tool-usersuspension-form-container">';

            echo '<div>';

            static::print_view_tabs($url->params(), 'exclusions');

            echo '</div>';

            echo $mform->display();

            echo '</div>';

            echo $OUTPUT->footer();

        }

    }

    /**

     * Process the view for user exclusion.

     * This will display or process the exclusion form for user exclusion.

     *

     * @param \moodle_url $url

     */

    public static function view_process_user_exclusion($url) {

        global $CFG, $OUTPUT;

        require_once($CFG->dirroot . '/' . $CFG->admin . '/tool/usersuspension/classes/forms/exclude/user.php');

        $formurl = clone $url;

        $formurl->param('action', 'add');

        $formurl->param('addtype', 'user');

        $mform = new forms\exclude\user($formurl);

        if ($mform->is_cancelled()) {

            redirect($url);

        } else if ($data = $mform->get_data()) {

            echo $OUTPUT->header();

            echo '<div id="tool-usersuspension-form-container">';

            $mform->process();

            echo '<br/>';

            echo static::continue_button($url, get_string('button:backtoexclusions', 'tool_usersuspension'));

            echo '</div>';

            echo $OUTPUT->footer();

        } else {

            echo $OUTPUT->header();

            echo '<div id="tool-usersuspension-form-container">';

            echo '<div>';

            static::print_view_tabs($url->params(), 'exclusions');

            echo '</div>';

            echo $mform->display();

            echo '</div>';

            echo $OUTPUT->footer();

        }

    }

    /**

     * Send an e-mail due to a user being suspended

     *

     * @param \stdClass $user

     * @param bool $automated true if a result of automated suspension, false if suspending

     *              is a result of a manual action

     * @return void

     */

    public static function process_user_suspended_email($user, $automated = true) {

        if (!(bool)config::get('send_suspend_email')) {

            return false;

        }

        // Prepare and send email.

        $from = \core_user::get_support_user();

        $a = new \stdClass();

        $a->name = fullname($user);

        $a->timeinactive = static::format_timespan(config::get('smartdetect_suspendafter'));

        $a->contact = $from->email;

        $a->signature = fullname($from);

        $subject = get_string_manager()->get_string('email:user:suspend:subject',

                'tool_usersuspension', $a, $user->lang);

        if ($automated) {

            $messagehtml = get_string_manager()->get_string('email:user:suspend:auto:body',

                    'tool_usersuspension', $a, $user->lang);

        } else {

            $messagehtml = get_string_manager()->get_string('email:user:suspend:manual:body',

                    'tool_usersuspension', $a, $user->lang);

        }

        $messagetext = format_text_email($messagehtml, FORMAT_HTML);

        return email_to_user($user, $from, $subject, $messagetext, $messagehtml);

    }

    /**

     * Send an e-mail due to a user facing suspension due to inactivity.

     *

     * @param \stdClass $user

     * @return void

     */

    public static function process_user_warning_email($user) {

        // Prepare and send email.

        $from = \core_user::get_support_user();

        $a = new \stdClass();

        $a->name = fullname($user);

        $a->suspendinterval = static::format_timespan(config::get('smartdetect_suspendafter'));

        $a->warningperiod = static::format_timespan(config::get('smartdetect_warninginterval'));

        $a->contact = $from->email;

        $a->signature = fullname($from);

        $subject = get_string('email:user:warning:subject', 'tool_usersuspension', $a);

        $messagehtml = get_string('email:user:warning:body', 'tool_usersuspension', $a);

        $messagetext = format_text_email($messagehtml, FORMAT_HTML);

        return email_to_user($user, $from, $subject, $messagetext, $messagehtml);

    }

    /**

     * Send an e-mail due to a user being unsuspended

     *

     * @param \stdClass $user

     * @return void

     */

    public static function process_user_unsuspended_email($user) {

        if (!(bool)config::get('send_suspend_email')) {

            return false;

        }

        // Prepare and send email.

        $from = \core_user::get_support_user();

        $a = new \stdClass();

        $a->name = fullname($user);

        $a->contact = $from->email;

        $a->signature = fullname($from);

        $subject = get_string_manager()->get_string('email:user:unsuspend:subject',

                'tool_usersuspension', $a, $user->lang);

        $messagehtml = get_string_manager()->get_string('email:user:unsuspend:body',

                'tool_usersuspension', $a, $user->lang);

        $messagetext = format_text_email($messagehtml, FORMAT_HTML);

        return email_to_user($user, $from, $subject, $messagetext, $messagehtml);

    }

    /**

     * Send an e-mail due to a user being deleted

     *

     * @param \stdClass $user

     * @return bool true if sent, false if disabled or error

     */

    public static function process_user_deleted_email($user) {

        if (!(bool)config::get('send_delete_email')) {

            return false;

        }

        // Prepare and send email.

        $from = \core_user::get_support_user();

        $a = new \stdClass();

        $a->name = fullname($user);

        $a->timesuspended = static::format_timespan(config::get('cleanup_deleteafter'));

        $a->contact = $from->email;

        $a->signature = fullname($from);

        $subject = get_string_manager()->get_string('email:user:delete:subject',

                'tool_usersuspension', $a, $user->lang);

        $messagehtml = get_string_manager()->get_string('email:user:delete:body',

                'tool_usersuspension', $a, $user->lang);

        $messagetext = format_text_email($messagehtml, FORMAT_HTML);

        return email_to_user($user, $from, $subject, $messagetext, $messagehtml);

    }

    /**

     * Clean history logs (if enabled in global config) older than the configured duration.

     *

     * @return boolean

     */

    public static function clean_logs() {

        global $DB;

        if (!(bool)config::get('enablecleanlogs')) {

            return false;

        }

        $DB->delete_records_select('tool_usersuspension_log', 'timecreated < ?',

                array(time() - (int)config::get('cleanlogsafter')));

        return true;

    }

    /**

     * Print a notification message.

     *

     * @param string $msg the notification message to display

     * @param string $class class or type of message. Please use either 'success' or 'error'

     * @return void

     */

    public static function print_notification($msg, $class = 'success') {

        global $OUTPUT;

        $pix = '<img src="' . $OUTPUT->image_url('msg_' . $class, 'tool_usersuspension') . '"/>';

        echo '<div class="tool-usersuspension-notification-' . $class . '">' . $pix . ' ' . $msg . '</div>';

    }

    /**

     * Returns HTML to display a continue button that goes to a particular URL.

     *

     * @param string|moodle_url $url The url the button goes to.

     * @param string $buttontext the text to show on the button.

     * @return string the HTML to output.

     */

    public static function continue_button($url, $buttontext) {

        global $OUTPUT;

        if (!($url instanceof \moodle_url)) {

            $url = new \moodle_url($url);

        }

        $button = new \single_button($url, $buttontext, 'get');

        $button->class = 'continuebutton';

        return $OUTPUT->render($button);

    }

    /**

     * Create a tab object with a nice image view, instead of just a regular tabobject

     *

     * @param string $id unique id of the tab in this tree, it is used to find selected and/or inactive tabs

     * @param string $pix image name

     * @param string $component component where the image will be looked for

     * @param string|moodle_url $link

     * @param string $text text on the tab

     * @param string $title title under the link, by defaul equals to text

     * @param bool $linkedwhenselected whether to display a link under the tab name when it's selected

     * @return \tabobject

     */

    public static function pictabobject($id, $pix = null, $component = 'tool_usersuspension', $link = null,

            $text = '', $title = '', $linkedwhenselected = false) {

        global $OUTPUT;

        $img = '';

        if ($pix !== null) {

            $img = '<img src="' . $OUTPUT->image_url($pix, $component) . '"> ';

        }

        return new \tabobject($id, $link, $img . $text, empty($title) ? $text : $title, $linkedwhenselected);

    }

    /**

     * print the tabs for the overview pages.

     *

     * @param array $params basic url parameters

     * @param string $selected id of the selected tab

     */

    public static function print_view_tabs($params, $selected) {

        global $CFG, $OUTPUT;

        $tabs = array();

        // Add exclusions.

        $exclusions = static::pictabobject('exclusions', 'exclusions', 'tool_usersuspension',

            new \moodle_url('/' . $CFG->admin . '/tool/usersuspension/view/exclude.php', $params),

                get_string('table:exclusions', 'tool_usersuspension'));

        $exclusions->subtree[] = static::pictabobject('excludeaddcohort', null, 'tool_usersuspension',

            new \moodle_url('/' . $CFG->admin . '/tool/usersuspension/view/exclude.php',

                    $params + array('action' => 'add', 'addtype' => 'cohort', 'sesskey' => sesskey())),

                get_string('action:exclude:add:cohort', 'tool_usersuspension'));

        $exclusions->subtree[] = static::pictabobject('excludeadduser', null, 'tool_usersuspension',

            new \moodle_url('/' . $CFG->admin . '/tool/usersuspension/view/exclude.php',

                    $params + array('action' => 'add', 'addtype' => 'user', 'sesskey' => sesskey())),

                get_string('action:exclude:add:user', 'tool_usersuspension'));

        $tabs[] = $exclusions;

        // Add statuslist tabs.

        foreach (statustable::get_viewtypes() as $type) {

            $url = new \moodle_url('/' . $CFG->admin . '/tool/usersuspension/view/statuslist.php', $params);

            $url->param('type', $type);

            $counter = '';

            switch ($type) {

                case statustable::DELETE:

                    $counter = ' (' . static::count_users_to_delete() . ')';

                    break;

                case statustable::SUSPENDED:

                    $counter = ' (' . static::count_suspended_users() . ')';

                    break;

                case statustable::TOSUSPEND:

                    $counter = ' (' . static::count_users_to_suspend() . ')';

                    break;

                case statustable::STATUS:

                    $counter = ' (' . static::count_monitored_users() . ')';

                    break;

            }

            $tabs[] = static::pictabobject($type, 'status_' . $type, 'tool_usersuspension',

                    $url, get_string('table:status:' . $type, 'tool_usersuspension') . $counter);

        }

        // Add upload tab.

        if ((bool)config::get('enablefromupload')) {

            $upload = static::pictabobject('upload', 'upload', 'tool_usersuspension',

                new \moodle_url('/' . $CFG->admin . '/tool/usersuspension/view/upload.php', $params),

                    get_string('link:upload', 'tool_usersuspension'));

            $tabs[] = $upload;

        }

        // Add logs tabs.

        $logs = static::pictabobject('logs', 'logs', 'tool_usersuspension',

            new \moodle_url('/' . $CFG->admin . '/tool/usersuspension/view/log.php', $params + array('history' => 0)),

                get_string('table:logs', 'tool_usersuspension'));

        $logs->subtree[] = static::pictabobject('log_latest', null, 'tool_usersuspension',

            new \moodle_url('/' . $CFG->admin . '/tool/usersuspension/view/log.php', $params + array('history' => 0)),

                get_string('table:log:latest', 'tool_usersuspension'));

        $logs->subtree[] = static::pictabobject('log_all', null, 'tool_usersuspension',

            new \moodle_url('/' . $CFG->admin . '/tool/usersuspension/view/log.php', $params + array('history' => 1)),

                get_string('table:log:all', 'tool_usersuspension'));

        $tabs[] = $logs;

        // Add tests.

        $testfromfolder = static::pictabobject('testfromfolder', null, 'tool_usersuspension',

            new \moodle_url('/' . $CFG->admin . '/tool/usersuspension/view/testfromfolder.php', $params),

                get_string('testfromfolder', 'tool_usersuspension'));

        $tabs[] = $testfromfolder;

        // Add notifications tabs.

        $notifications = static::pictabobject('notifications', null, 'tool_usersuspension',

            new \moodle_url('/' . $CFG->admin . '/tool/usersuspension/view/notifications.php', $params),

                get_string('tab:notifications', 'tool_usersuspension'));

        $tabs[] = $notifications;

        echo $OUTPUT->tabtree($tabs, $selected);

    }

    /**

     * Generate messages (using core notifications) for (every) frontpage in this tool.

     */

    public static function generate_notifications() {

        $messages = [];

        // Main plugin enabled.

        if (!(bool)config::get('enabled')) {

            $messages[] = get_string('config:tool:disabled', 'tool_usersuspension');

        }

        // Auto-suspend enabled.

        if (!(bool)config::get('enablesmartdetect')) {

            $messages[] = get_string('config:smartdetect:disabled', 'tool_usersuspension');

        }

        // Auto-delete enabled.

        if (!(bool)config::get('enablecleanup')) {

            $messages[] = get_string('config:cleanup:disabled', 'tool_usersuspension');

        }

        // Task(s).

        if (!(bool)config::get('enableunsuspendfromfolder')) {

            $messages[] = get_string('config:unsuspendfromfolder:disabled', 'tool_usersuspension');

        }

        if (!(bool)config::get('enablefromfolder')) {

            $messages[] = get_string('config:fromfolder:disabled', 'tool_usersuspension');

        }

        // Folder(s).

        $uploadedfolder = config::get('uploadfolder');

        if (!file_exists($uploadedfolder) || !is_dir($uploadedfolder)) {

            $messages[] = 'CSV upload folder "'.$uploadedfolder.'" does not exist';

        }

        if (!is_readable($uploadedfolder) || !is_dir($uploadedfolder)) {

            $messages[] = 'CSV upload folder "'.$uploadedfolder.'" is not readable';

        }

        if (!empty($messages)) {

            return \html_writer::div(implode('<br/>', $messages), 'alert alert-warning');

        } else {

            return \html_writer::div(get_string('notifications:allok', 'tool_usersuspension'), 'alert alert-success');

        }

    }

}