<?php
# Lifter010: TODO

/*
 *  This class is the module for the seminar-schedules in Stud.IP
 *
 * This program 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 2 of
 * the License, or (at your option) any later version.
 *
 * @author      Till Glöggler <tgloeggl@uos.de>
 * @license     http://www.gnu.org/licenses/gpl-2.0.html GPL version 2
 * @category    Stud.IP
 */

require_once __DIR__ . '/default_color_definitions.php';

/**
 * Pseudo-namespace containing helper methods for the schedule.
 *
 * @since      2.0
 *
 * @deprecated since Stud.IP 5.5
 */
class CalendarScheduleModel
{

    /**
     * update an existing entry or -if $data['id'] is not set- create a new entry
     *
     * @param  mixed  $data
     */
    static function storeEntry($data)
    {
        if (!empty($data['id'])) {     // update
            $stmt = DBManager::get()->prepare("UPDATE schedule
                SET start = ?, end = ?, day = ?, title = ?, content = ?, color = ?, user_id = ?
                WHERE id = ?");
            $stmt->execute([$data['start'], $data['end'], $data['day'], $data['title'],
                $data['content'], $data['color'], $data['user_id'], $data['id']]);

            NotificationCenter::postNotification('ScheduleDidUpdate', $GLOBALS['user']->id ?? null, ['values' => $data]);

        } else {
            $stmt = DBManager::get()->prepare("INSERT INTO schedule
                (start, end, day, title, content, color, user_id)
                VALUES (?, ?, ?, ?, ?, ?, ?)");
            $stmt->execute([$data['start'], $data['end'], $data['day'], $data['title'],
                $data['content'], $data['color'], $data['user_id']]);
            NotificationCenter::postNotification('ScheduleDidCreate', $GLOBALS['user']->id ?? null, ['values' => $data]);
        }
    }

    /**
     * Update an existing entry of a course or create a new entry if $data['id'] is not set
     *
     * @param mixed  $data  the data to store
     * @return void
     */
    static function storeSeminarEntry($data)
    {
        $stmt = DBManager::get()->prepare("REPLACE INTO schedule_seminare
            (seminar_id, user_id, metadate_id, color) VALUES(?, ? ,?, ?)");

        $stmt->execute([$data['id'], $GLOBALS['user']->id, $data['cycle_id'], $data['color']]);
        NotificationCenter::postNotification('ScheduleSeminarDidCreate', $GLOBALS['user']->id, $data['cycle_id']);
    }

    /**
     * delete the entry with the submitted id, belonging to the current user
     *
     * @param  string  $id
     * @return void
     */
    static function deleteEntry($id)
    {
        $stmt = DBManager::get()->prepare("DELETE FROM schedule
            WHERE id = ? AND user_id = ?");
        $stmt->execute([$id, $GLOBALS['user']->id]);
        NotificationCenter::postNotification('ScheduleDidDelete', $GLOBALS['user']->id, $id);
    }


    /**
     * Returns an array of CalendarColumn's containing the
     * schedule entries (optionally of a given id only).
     * The start- and end-hour are used to constrain the returned
     * entries to the passed time-period.
     * If you pass an id, there will be only the single entry with that id in
     * the CalendarColumn
     *
     * @param string  $user_id the  ID of the user
     * @param int     $start_hour   the start hour
     * @param int     $end_hour     the end hour
     * @param string  $id           optional; the ID of the schedule-entry
     * @return array  an array containing the entries
     */
    static function getScheduleEntries($user_id, $start_hour, $end_hour, $id = false)
    {
        $ret = [];

        // fetch user-generated entries
        if (!$id) {
            $stmt = DBManager::get()->prepare("SELECT * FROM schedule
                WHERE user_id = ? AND (
                    (start >= ? AND end <= ?)
                    OR (start <= ? AND end >= ?)
                    OR (start <= ? AND end >= ?)
                )");
            $start = $start_hour * 100;
            $end   = $end_hour   * 100;
            $stmt->execute([$user_id, $start, $end, $start, $start, $end, $end]);
        } else {
            $stmt = DBManager::get()->prepare("SELECT * FROM schedule
                WHERE user_id = ? AND id = ?");
            $stmt->execute([$user_id, $id]);
        }

        $entries = $stmt->fetchAll(PDO::FETCH_ASSOC);
        foreach($entries as $entry) {
            $entry['start_formatted'] = sprintf("%02d", floor($entry['start'] / 100)) .':'. sprintf("%02d", floor($entry['start'] % 100));
            $entry['end_formatted'] = sprintf("%02d", floor($entry['end'] / 100)) .':'. sprintf("%02d", floor($entry['end'] % 100));
            $entry['title']        = $entry['title'];
            $entry['content']      = $entry['content'];
            $entry['start_hour']   = sprintf("%02d", floor($entry['start'] / 100));
            $entry['start_minute'] = sprintf("%02d", $entry['start'] % 100);
            $entry['end_hour']     = sprintf("%02d", floor($entry['end'] / 100));
            $entry['end_minute']   = sprintf("%02d", $entry['end'] % 100);
            $entry['url']          = URLHelper::getLink('dispatch.php/calendar/schedule/entry/' . $entry['id']);
            $entry['onClick']      = "function (id) { STUDIP.Schedule.showScheduleDetails('". $entry['id'] ."'); }";
            $entry['visible']      = true;

            $day_number = ($entry['day']-1) % 7;
            if (!isset($ret[$day_number])) {
                $ret[$day_number] = CalendarColumn::create($day_number);
            }
            $ret[$day_number]->addEntry($entry);
        }

        return $ret;
    }

    /**
     * Return an entry for the specified course.
     *
     * @param string  $seminar_id  the ID of the course
     * @param string  $user_id     the ID of the user
     * @param mixed   $cycle_id    either false or the ID of the cycle
     * @param mixed   $semester    filter for this semester
     *
     * @return array  the course's entry
     */
    static function getSeminarEntry($seminar_id, $user_id, $cycle_id = false, $semester = false)
    {
        $ret = [];
        $filterStart = 0;
        $filterEnd   = 0;

        // filter dates (and their rooms) if semester is passed
        if ($semester) {
            $filterStart = $semester['vorles_beginn'];
            $filterEnd   = $semester['vorles_ende'];
        }

        $sem = new Seminar($seminar_id);
        foreach ($sem->getCycles() as $cycle) {
            if (!$cycle_id || $cycle->getMetaDateID() == $cycle_id) {
                $entry = [];

                $entry['id'] = $seminar_id .'-'. $cycle->getMetaDateId();
                $entry['cycle_id'] = $cycle->getMetaDateId();
                $entry['start_formatted'] = sprintf("%02d", $cycle->getStartStunde()) .':'
                    . sprintf("%02d", $cycle->getStartMinute());
                $entry['end_formatted'] = sprintf("%02d", $cycle->getEndStunde()) .':'
                    . sprintf("%02d", $cycle->getEndMinute());

                $entry['start']   = ((int)$cycle->getStartStunde() * 100) + ($cycle->getStartMinute());
                $entry['end']     = ((int)$cycle->getEndStunde() * 100) + ($cycle->getEndMinute());
                $entry['day']     = $cycle->getDay();
                $entry['content'] = $sem->getNumber() . ' ' . $sem->getName();

                $entry['title']   = $cycle->getDescription();

                // check, if the date is assigned to a room
                if ($rooms = $cycle->getPredominantRoom($filterStart, $filterEnd)) {
                    $entry['title'] .= implode('', getPlainRooms(array_slice($rooms, 0, 1)))
                                    . (sizeof($rooms) > 1 ? ', u.a.' : '');
                } else if ($rooms = $cycle->getFreeTextPredominantRoom($filterStart, $filterEnd)) {
                    unset($rooms['']);
                    if (!empty($rooms)) {
                        $entry['title'] .= '('. implode('), (', array_slice(array_keys($rooms), 0, 3)) .')';
                    }
                }

                // add the lecturer
                $lecturers = [];
                $members = $sem->getMembers('dozent');

                foreach ($members as $member) {
                    $lecturers[] = $member['Nachname'];
                }
                $entry['content'] .= " (". implode(', ', array_slice($lecturers, 0, 3))
                                  . (sizeof($members) > 3 ? ' et al.' : '').')';


                $entry['url']     = URLHelper::getLink('dispatch.php/calendar/schedule/entry/' . $seminar_id
                                  . '/' . $cycle->getMetaDateId());
                $entry['onClick'] = "function (id) {
                    var ids = id.split('-');
                    STUDIP.Schedule.showSeminarDetails(ids[0], ids[1]);
                }";


                // check the settings for this entry
                $member = CourseMember::find([$sem->getId(), $user_id]);
                $entry['type'] = $member ? 'sem' : 'virtual';

                $stmt = DBManager::get()->prepare('SELECT * FROM schedule_seminare WHERE seminar_id = ? AND user_id = ? AND metadate_id = ?');
                $stmt->execute([$sem->getId(), $user_id, $cycle->getMetaDateId()]);
                $details = $stmt->fetch();

                if ($entry['type'] === 'virtual') {
                    $entry['color'] = $details ? ($details['color'] ?: DEFAULT_COLOR_VIRTUAL) : DEFAULT_COLOR_VIRTUAL;
                    $entry['icons'][] = [
                        'image' => Icon::create('tag', Icon::ROLE_INFO_ALT)->asImagePath(),
                        'title' => _("Dies ist eine vorgemerkte Veranstaltung")
                    ];
                } else {
                    $entry['color'] = !empty($details['color']) ? $details['color'] : ($member->gruppe % 9 + 1);
                }
                $entry['visible'] = $details ? $details['visible'] : 1;

                // show an unhide icon if entry is invisible
                if (!$entry['visible']) {
                    $entry['url'] .= '/?show_hidden=1';

                    $bind_url = URLHelper::getLink('dispatch.php/calendar/schedule/bind/'
                              . $seminar_id . '/' . $cycle->getMetaDateId() . '/?show_hidden=1');

                    $entry['icons'][] = [
                        'url'   => $bind_url,
                        'image' => Icon::create('visibility-invisible', Icon::ROLE_INFO_ALT)->asImagePath(),
                        'onClick' => "function(id) { window.location = '". $bind_url ."'; }",
                        'title' => _("Diesen Eintrag wieder einblenden"),
                    ];
                }

                // show a hide-icon if the entry is not virtual
                else if ($entry['type'] != 'virtual') {
                    $unbind_url = URLHelper::getLink('dispatch.php/calendar/schedule/unbind/'
                                . $seminar_id . '/' . $cycle->getMetaDateId());
                    $entry['icons'][] = [
                        'url'     => $unbind_url,
                        'image'   => Icon::create('visibility-visible', Icon::ROLE_INFO_ALT)->asImagePath(),
                        'onClick' => "function(id) { window.location = '". $unbind_url ."'; }",
                        'title'   => _("Diesen Eintrag ausblenden"),
                    ];

                }

                $ret[] = $entry;
            }
        }

        return $ret;
    }

    /**
     * Deletes the schedule entries of one user for one seminar.
     *
     * @param string  $user_id     the user of the schedule
     * @param string  $seminar_id  the seminar which entries should be deleted
     */
    static function deleteSeminarEntries($user_id, $seminar_id)
    {
        $stmt = DBManager::get()->prepare($query = "DELETE FROM schedule_seminare
            WHERE user_id = ? AND seminar_id = ?");
        $stmt->execute([$user_id, $seminar_id]);
        NotificationCenter::postNotification('ScheduleSeminarDidDelete', $GLOBALS['user']->id, $seminar_id);
    }

    /**
     * Returns an array of CalendarColumn's, containing the seminar-entries
     * for the passed user in the passed semester.
     * The start- and end-hour are used to constrain the returned
     * entries to the passed time-period.
     * Seminar-entries can be hidden, so you can opt-in to fetch the hidden
     * ones as well.
     *
     * @param string  $user_id      the ID of the user
     * @param string  $semester     an array containing the "beginn" of the semester
     * @param int     $start_hour   the start hour
     * @param int     $end_hour     the end hour
     * @param string  $show_hidden  optional; true to show hidden, false otherwise
     * @return array  an array containing the properties of the entry
     */
    static function getSeminarEntries($user_id, $semester, $start_hour, $end_hour, $show_hidden = false)
    {
        $seminars = [];

        // get all virtually added seminars
        $stmt = DBManager::get()->prepare("SELECT * FROM schedule_seminare as c
            LEFT JOIN seminare as s ON (s.Seminar_id = c.Seminar_id)
            LEFT JOIN semester_courses ON (semester_courses.course_id = s.Seminar_id)
            WHERE c.user_id = ? AND s.start_time <= ? AND
                (semester_courses.semester_id IS NULL OR semester_courses.semester_id = ?)");
        $stmt->execute([$user_id, $semester['beginn'], $semester['id']]);

        while ($entry = $stmt->fetch()) {
            $seminars[$entry['seminar_id']] = [
                'Seminar_id' => $entry['seminar_id']
            ];
        }

        // fetch seminar-entries
        $stmt = DBManager::get()->prepare("SELECT s.Seminar_id FROM seminar_user as su
            LEFT JOIN seminare as s USING (Seminar_id)
            LEFT JOIN semester_courses ON (semester_courses.course_id = s.Seminar_id)
            WHERE su.user_id = :userid
                AND s.start_time <= :begin
                AND (semester_courses.semester_id IS NULL OR semester_courses.semester_id = :semester_id)
               ");
        $stmt->bindValue(':begin', $semester['beginn']);
        $stmt->bindValue(':semester_id', $semester['semester_id']);
        $stmt->bindValue(':userid', $user_id);
        $stmt->execute();

        while ($entry = $stmt->fetch(PDO::FETCH_ASSOC)) {
            $seminars[$entry['Seminar_id']] = [
                'Seminar_id' => $entry['Seminar_id']
            ];
        }

        $ret = [];
        foreach ($seminars as $data) {
            $entries = self::getSeminarEntry($data['Seminar_id'], $user_id, false, $semester);

            foreach ($entries as $entry) {
                if (($entry['start'] >= $start_hour * 100 && $entry['start'] <= $end_hour * 100
                    || $entry['end'] >= $start_hour * 100 && $entry['end'] <= $end_hour * 100)
                    && ($show_hidden || (!$show_hidden && $entry['visible']))) {
                    $day_number = ($entry['day'] + 6) % 7;
                    if (!isset($ret[$day_number])) {
                        $ret[$day_number] = new CalendarColumn();
                    }

                    $ret[$day_number]->addEntry($entry);
                }
            }
        }

        return $ret;

    }


    /**
     * Returns an array of CalendarColumn's, containing the seminar-entries
     * for the passed user in the passed semester belonging to the passed institute.
     * The start- and end-hour are used to constrain the returned
     * entries to the passed time-period.
     *
     * @param string  $user_id       the ID of the user
     * @param array   $semester      an array containing the "beginn" of the semester
     * @param int     $start_hour    the start hour
     * @param int     $end_hour      the end hour
     * @param string  $institute_id  the ID of the institute
     * @return array  an array containing the entries
     */
    static function getSeminarEntriesForInstitute($user_id, $semester, $start_hour, $end_hour, $institute_id)
    {
        $ret = [];

        // fetch seminar-entries
        $visibility_perms = $GLOBALS['perm']->have_perm(Config::get()->SEM_VISIBILITY_PERM);
        $stmt = DBManager::get()->prepare("SELECT *
            FROM seminare
            LEFT JOIN semester_courses ON (semester_courses.course_id = seminare.Seminar_id)
            WHERE Institut_id = :institute
                AND start_time <= :begin
                AND (semester_courses.semester_id IS NULL OR semester_courses.semester_id = :semester_id) "
                . (!$visibility_perms ? " AND visible='1'" : ""));

        $stmt->bindParam(':begin', $semester['beginn']);
        $stmt->bindParam(':semester_id', $semester['semester_id']);
        $stmt->bindParam(':institute', $institute_id);
        $stmt->execute();

        $seminars = $stmt->fetchAll(PDO::FETCH_ASSOC);

        foreach ($seminars as $data) {
            $entries = self::getSeminarEntry($data['Seminar_id'], $user_id, false, $semester);

            foreach ($entries as $entry) {
                unset($entry['url']);
                $entry['onClick'] = 'function(id) { STUDIP.Schedule.showInstituteDetails(id); }';

                if (($entry['start'] >= $start_hour * 100 && $entry['start'] <= $end_hour * 100
                    || $entry['end'] >= $start_hour * 100 && $entry['end'] <= $end_hour * 100)) {

                    $entry['color'] = DEFAULT_COLOR_SEM;

                    $day_number = ($entry['day'] + 6) % 7;
                    if (!isset($ret[$day_number])) {
                        $ret[$day_number] = CalendarColumn::create($entry['day']);
                    }

                    $ret[$day_number]->addEntry($entry);
                }
            }
        }

        return $ret;
    }


    /**
     * Returns the ID of the cycle of a course specified by start and end.
     *
     * @param  Seminar $seminar  an instance of a Seminar
     * @param  string  $start  the start of the cycle
     * @param  string  $end  the end of the cycle
     * @return string  $day  numeric day
     */
    static function getSeminarCycleId(Seminar $seminar, $start, $end, $day)
    {
        $ret = [];

        $day = ($day + 1) % 7;

        foreach ($seminar->getCycles() as $cycle) {
            if (leadingZero($cycle->getStartStunde()) . leadingZero($cycle->getStartMinute()) == $start
                && leadingZero($cycle->getEndStunde()) . leadingZero($cycle->getEndMinute()) == $end
                && $cycle->getDay() == $day) {
                $ret[] = $cycle;
            }
        }

        return $ret;
    }

    /**
     * check if the passed cycle of the passed id is visible
     * for the currently logged in user int the schedule
     *
     * @param  string the ID of the course
     * @param  string the ID of the cycle
     * @return bool true if visible, false otherwise
     */
    static function isSeminarVisible($seminar_id, $cycle_id)
    {
        $stmt = DBManager::get()->prepare("SELECT visible
            FROM schedule_seminare
            WHERE seminar_id = ? AND user_id = ? AND metadate_id = ?");
        $stmt->execute([$seminar_id, $GLOBALS['user']->id, $cycle_id]);
        if (!$data = $stmt->fetch()) {
            return true;
        } else {
            return $data['visible'] ? true : false;
        }
    }

    /**
     * Returns an array of CalendarColumn's, containing the seminar-entries
     * for the passed user (in the passed semester belonging to the passed institute)
     * and the user-defined schedule-entries.
     * The start- and end-hour are used to constrain the returned
     * entries to the passed time-period. The passed days constrain the entries
     * to these.
     * Seminar-entries can be hidden, so you can opt-in to fetch the hidden
     * ones as well.
     *
     * @param string  $user_id       the user's ID
     * @param string  $semester      the data for the semester to be displayed
     * @param int     $start_hour    the start hour of the entries
     * @param int     $end_hour      the end hour of the entries
     * @param string  $institute_id  the institute's ID
     * @param array   $days          days to be displayed
     * @param bool    $show_hidden   filters hidden entries
     * @return array  an array of entries
     */
    static function getInstituteEntries($user_id, $semester, $start_hour, $end_hour, $institute_id, $days, $show_hidden = false)
    {
        // merge the schedule and seminar-entries
        $entries = self::getScheduleEntries($user_id, $start_hour, $end_hour, false);
        $seminar = self::getSeminarEntriesForInstitute($user_id, $semester, $start_hour, $end_hour, $institute_id, $show_hidden);

        foreach($seminar as $day => $entry_column) {
            foreach ($entry_column->getEntries() as $entry) {
                if (!isset($entries[$day])) {
                    $entries[$day] = CalendarColumn::create($day);
                }
                $entries[$day]->addEntry($entry);
            }
        }

        return self::addDayChooser($entries, $days);
    }

    /**
     *
     *
     * @param  string  $user_id
     * @param  mixed   $semester  the data for the semester to be displayed
     */

    /**
     * Returns an array of CalendarColumn's, containing the seminar-entries
     * for the passed user (in the passed semester) and the user-defined schedule-entries.
     * The start- and end-hour are used to constrain the returned
     * entries to the passed time-period. The passed days constrain the entries
     * to these.
     * Seminar-entries can be hidden, so you can opt-in to fetch the hidden
     * ones as well.
     *
     * @param string  $user_id       the user's ID
     * @param string  $semester      the data for the semester to be displayed
     * @param int     $start_hour    the start hour of the entries
     * @param int     $end_hour      the end hour of the entries
     * @param array   $days          days to be displayed
     * @param bool    $show_hidden   filters hidden entries
     * @return array
     */
    static function getEntries($user_id, $semester, $start_hour, $end_hour, $days, $show_hidden = false)
    {
        // merge the schedule and seminar-entries
        $entries = self::getScheduleEntries($user_id, $start_hour, $end_hour, false);
        $seminar = self::getSeminarEntries($user_id, $semester, $start_hour, $end_hour, $show_hidden);
        foreach($seminar as $day => $entry_column) {
            foreach ($entry_column->getEntries() as $entry) {
                if (!isset($entries[$day])) {
                    $entries[$day] = CalendarColumn::create($day);
                }
                $entries[$day]->addEntry($entry);
            }
        }

        return self::addDayChooser($entries, $days);
    }

    /**
     * adds title and link to CalendarColumn-objects and sorts the objects to be
     * displayed correctly in the calendar-view
     *
     * @param array $entries  an array of CalendarColumn-objects
     * @param array $days     an array of int's, denoting the days to be displayed
     * @return array
     */
    static function addDayChooser($entries, $days, $controller = 'schedule') {
        $day_names  = [_("Mo"),_("Di"),_("Mi"),
            _("Do"),_("Fr"),_("Sa"),_("So")];

        $ret = [];

        foreach ($days as $day) {
            if (!isset($entries[$day])) {
                $ret[$day] = CalendarColumn::create($day);
            } else {
                $ret[$day] = $entries[$day];
            }

            if (sizeof($days) == 1) {
                $ret[$day]->setTitle($day_names[$day] .' ('. _('zurück zur Wochenansicht') .')')
                    ->setURL('dispatch.php/calendar/'. $controller .'/index');
            } else {
                $ret[$day]->setTitle($day_names[$day])
                    ->setURL('dispatch.php/calendar/'. $controller .'/index/'. $day);
            }
        }

        return $ret;
    }

    /**
     * Toggle entries' visibility
     *
     * @param  string  $seminar_id  the course's ID
     * @param  string  $cycle_id    the cycle's ID
     * @param  bool    $visible     the value to switch to
     * @return void
     */
    static function adminBind($seminar_id, $cycle_id, $visible = true)
    {
        $stmt = DBManager::get()->prepare("SELECT * FROM schedule_seminare
            WHERE seminar_id = ? AND user_id = ? AND metadate_id = ?");
        $stmt->execute([$seminar_id, $GLOBALS['user']->id, $cycle_id]);

        if ($stmt->fetch()) {
            $stmt = DBManager::get()->prepare("UPDATE schedule_seminare
                SET visible = ?
                WHERE seminar_id = ? AND user_id = ? AND metadate_id = ?");
        } else {
            $stmt = DBManager::get()->prepare("INSERT INTO schedule_seminare
                (visible, seminar_id, user_id, metadate_id)
                VALUES(?, ?, ?, ?)");
        }

        $stmt->execute([$visible ? '1' : '0', $seminar_id, $GLOBALS['user']->id, $cycle_id]);

    }

    /**
     * Switch a seminars' cycle to invisible.
     *
     * @param  string  $seminar_id  the course's ID
     * @param  string  $cycle_id    the cycle's ID
     * @return void
     */
    public static function unbind($seminar_id, $cycle_id = null)
    {
        $stmt = DBManager::get()->prepare("SELECT su.*, sc.seminar_id as present
            FROM seminar_user as su
            LEFT JOIN schedule_seminare as sc ON (su.Seminar_id = sc.seminar_id
                AND sc.user_id = su.user_id AND sc.metadate_id = ?)
            WHERE su.Seminar_id = ? AND su.user_id = ?");
        $stmt->execute([$cycle_id, $seminar_id, $GLOBALS['user']->id]);

        // if we are participant of the seminar, just hide the entry
        if ($data = $stmt->fetch()) {
            if ($data['present']) {
                $stmt = DBManager::get()->prepare("UPDATE schedule_seminare
                    SET visible = 0
                    WHERE seminar_id = ? AND user_id = ? AND metadate_id = ?");
            } else {
                $stmt = DBManager::get()->prepare("INSERT IGNORE INTO schedule_seminare
                    (seminar_id, user_id, metadate_id, visible)
                    VALUES(?, ?, ?, 0)");
            }
            $stmt->execute([$seminar_id, $GLOBALS['user']->id, $cycle_id]);
        }

        // otherwise delete the entry
        else {
            $stmt = DBManager::get()->prepare("DELETE FROM schedule_seminare
                WHERE seminar_id = ? AND user_id = ?");
            $stmt->execute([$seminar_id, $GLOBALS['user']->id]);
            NotificationCenter::postNotification('ScheduleSeminarDidDelete', $GLOBALS['user']->id, $seminar_id);
        }
    }

    /**
     * Switch a seminars' cycle to visible.
     *
     * @param  string  $seminar_id  the course's ID
     * @param  string  $cycle_id    the cycle's ID
     * @return void
     */
    static function bind($seminar_id, $cycle_id)
    {
        $stmt = DBManager::get()->prepare("UPDATE schedule_seminare
            SET visible = 1
            WHERE seminar_id = ? AND user_id = ? AND metadate_id = ?");

        $stmt->execute([$seminar_id, $GLOBALS['user']->id, $cycle_id]);
    }

    /**
     * Get the schedule_settings from the user's config
     *
     * @param string $user_id the user to get the settings for, defaults
     *                        to current user
     * @return mixed the settings
     */
    static function getScheduleSettings($user_id = false)
    {
        if (!$user_id) {
            $user_id = $GLOBALS['user']->id;
        }

        $schedule_settings = UserConfig::get($user_id)->SCHEDULE_SETTINGS;

        // convert old settings, if necessary (mein_stundenplan.php)
        if (!$schedule_settings['converted']) {
            $schedule_settings['glb_days'] = [0, 1, 2, 3, 4];
            $schedule_settings['converted'] = true;
        }

        return $schedule_settings;
    }

    /**
     * Transforms day settings from SCHEDULE_SETTINGS::glb_days to valid
     * days that can be displayed.
     *
     * @param  array  $input Input from SCHEDULE_SETTINGS
     * @return array
     */
    public static function getDisplayedDays(array $input)
    {
        $days = [];
        foreach ($input as $key => $value) {
            // Fallback for old entries (["mo": true, ...])
            if (!is_numeric($key) || !is_numeric($value)) {
                $days = [6, 0, 1, 2, 3];
                break;
            }
            $days[$key] = ($value + 6) % 7;
        }
        return $days;
    }

    /**
     * Return the semester-entry for the current semester
     *
     * @return mixed the current semester
     */
    static function getCurrentSemester()
    {
        return Semester::findCurrent();
    }

    /**
     * Create a CalendarWeekView (a schedule) for an institute
     * for the current user and return it.
     *
     * @param string $institute_id  the institute to get the calendar for
     * @param bool $show_hidden     show hidden entries
     * @param mixed $semester       the semester to use
     * @param mixed $days           the days to consider
     *
     * @return CalendarWeekView
     */
    static function getInstCalendarView($institute_id, $show_hidden = false, $semester = false, $days = false)
    {
        $schedule_settings = self::getScheduleSettings();

        if (!$semester) {
            $semester = self::getCurrentSemester();
        }

        if (!$days) {
            $days = self::getDisplayedDays($schedule_settings['glb_days']);
        }

        $user_id = $GLOBALS['user']->id;

        $entries = CalendarScheduleModel::getInstituteEntries(
            $user_id,
            $semester,
            $schedule_settings['glb_start_time'],
            $schedule_settings['glb_end_time'],
            $institute_id,
            $days,
            $show_hidden
        );

        $view = new CalendarWeekView($entries, 'schedule');

        $view->setHeight(40 + (20 * $schedule_settings['zoom']));
        $view->setRange($schedule_settings['glb_start_time'], $schedule_settings['glb_end_time']);

        // group entries in institute calendar
        $view->groupEntries();  // if enabled, group entries with same start- and end-date

        return $view;
    }

    /**
     * Create a CalendarWeekView (a schedule) for the current user and return it.
     *
     * @param string $user_id  the institute to get the calendar for
     * @param bool $show_hidden     show hidden entries
     * @param mixed $semester       the semester to use
     * @param mixed $days           the days to consider
     *
     * @return CalendarWeekView
     */
    static function getUserCalendarView($user_id, $show_hidden = false, $semester = false, $days = false)
    {
        $schedule_settings = self::getScheduleSettings($user_id);

        if (!$semester) {
            $semester = self::getCurrentSemester();
        }

        if (!$days) {
            $days = self::getDisplayedDays($schedule_settings['glb_days']);
        }

        $entries = CalendarScheduleModel::getEntries(
            $user_id,
            $semester,
            $schedule_settings['glb_start_time'],
            $schedule_settings['glb_end_time'],
            $days,
            $show_hidden
        );

        $view = new CalendarWeekView($entries, 'schedule');

        $view->setHeight(40 + (20 * ($schedule_settings['zoom'] ?? 0)));
        $view->setRange($schedule_settings['glb_start_time'], $schedule_settings['glb_end_time']);
        $view->setInsertFunction("function (entry, column, hour, end_hour) {
            STUDIP.Schedule.newEntry(entry, column, hour, end_hour)
        }");

        return $view;
    }
}