<?php
/**
 * Global search module for study groups
 *
 * @author      Michaela Brückner <brueckner@data-quest.de>
 * @license     http://www.gnu.org/licenses/gpl-2.0.html GPL version 2
 * @category    Stud.IP
 * @since       6.0
 */
class GlobalSearchStudygroups extends GlobalSearchModule implements GlobalSearchFulltext
{
    /**
     * Returns the displayname for this module
     *
     * @return string
     */
    public static function getName()
    {
        return _('Studiengruppen');
    }

    /**
     * Returns the filters that are displayed in the sidebar of the global search.
     *
     * @return array Filters for this class.
     */
    public static function getFilters()
    {
        return ['semester', 'study_course'];
    }

    /**
     * Transforms the search request into an sql statement, that provides the id (same as getId) as type and
     * the object id, that is later passed to the filter.
     *
     * This function is required to make use of the mysql union parallelism
     *
     * @param string $search the input query string
     * @param array $filter an array with search limiting filter information (e.g. 'category', 'semester', etc.)
     * @return string SQL Query to discover elements for the search
     */
    public static function getSQL($search, $filter, $limit)
    {
        if (!$search) {
            return null;
        }
        $search = str_replace(' ', '% ', $search);
        $query = DBManager::get()->quote("%{$search}%");

        $language_name = 'courses.`Name`';
        $language_join = '';
        if (I18N::isEnabled() && $_SESSION['_language'] !== I18NString::getDefaultLanguage()) {
            $language_name = 'IFNULL(`i18n`.`value`, courses.`Name`)';
            $language_join = "LEFT JOIN `i18n`
                                ON `i18n`.`object_id` = courses.`Seminar_id`
                                  AND `i18n`.`table` = 'seminare'
                                  AND `i18n`.`field` = 'name'
                                  AND `lang` = " . DBManager::get()->quote($_SESSION['_language']);
        }

        $visibility = '';
        $seminaruser = '';
        $semester_join = '';
        $institute_condition = '';
        $seminar_type_condition = '';
        $semester_condition = '';

        // visibility
        //if (!$GLOBALS['perm']->have_perm('admin')) {
            $visibility = "courses.`visible` = 1 AND ";
            $seminaruser = " AND EXISTS (
                SELECT 1 FROM `seminar_user`
                WHERE `seminar_id` = `courses`.`Seminar_id`
                    AND `user_id` = " . DBManager::get()->quote($GLOBALS['user']->id) . "
            ) ";
        //}

        // generate SQL for the given sidebar filter (semester, institute, seminar_type)
        if ($filter['category'] === self::class || $filter['category'] === 'show_all_categories') {
            if (!empty($filter['semester'])) {
                if ($filter['semester'] === 'future') {
                    $semester = Semester::findCurrent();
                    $next_semester = Semester::findNext();

                    $semester_ids = [$semester->id];
                    if ($next_semester) {
                        $semester_ids[] = $next_semester->id;
                    }
                } else {
                    $semester = Semester::findByTimestamp($filter['semester']);
                    $semester_ids = [$semester->id];
                }
                $semester_join = "LEFT JOIN semester_courses ON (courses.Seminar_id = semester_courses.course_id) ";
                $semester_condition = "
                    AND (
                        semester_courses.semester_id IS NULL OR semester_courses.semester_id IN (" . join(',', array_map([DBManager::get(), 'quote'], $semester_ids)) . ")
                    ) ";
            }
            $seminar_type_condition = " AND `courses`.`status` = '99' ";
        }

        $tags_join = "LEFT JOIN tags_relations ON courses.Seminar_id = tags_relations.range_id LEFT JOIN tags on tags_relations.tag_id = tags.id";
        $tags_name = "tags.name";

        $sql = "SELECT SQL_CALC_FOUND_ROWS courses.`Seminar_id`,
                       {$language_name} AS `Name`,
                       courses.`VeranstaltungsNummer`, courses.`status`,
                       {$tags_name}  AS `Tag`
                FROM `seminare` AS courses
                {$language_join}
                JOIN `seminar_user` u ON (u.`Seminar_id` = courses.`Seminar_id` AND u.`status` = 'dozent')
                JOIN `auth_user_md5` a ON (a.`user_id` = u.`user_id`)
                {$semester_join}
                {$tags_join}
                WHERE {$visibility}
                    (
                        {$language_name} LIKE {$query}
                        OR {$tags_name} LIKE {$query}
                        OR courses.`VeranstaltungsNummer` LIKE {$query}
                        OR CONCAT(a.`Nachname`, ', ', a.`Vorname`, ' ', a.`Nachname`) LIKE {$query}
                    )
                {$seminaruser}
                {$institute_condition}
                {$seminar_type_condition}
                {$semester_condition}
                GROUP BY courses.Seminar_id";

        if (Config::get()->IMPORTANT_SEMNUMBER) {
            $sql .= ", courses.`VeranstaltungsNummer`";
        }

        $sql .= ", `Name`";
        $sql .= " LIMIT " . $limit;


        return $sql;
    }

    /**
     * Returns an array of information for the found element. Following informations (key: description) are necessary
     *
     * - name: The name of the object
     * - url: The url to send the user to when he clicks the link
     *
     * Additional informations are:
     *
     * - additional: Subtitle for the hit
     * - expand: Url if the user further expands the search
     * - img: Avatar for the
     *
     * @param array $data
     * @param string $search
     * @return array
     */
    public static function filter($data, $search)
    {
        $course = Course::buildExisting($data);
        $turnus_string = implode(' ', $course->getAllDatesInSemester()->toStringArray());
        //Shorten, if string too long (add link for details.php)
        if (mb_strlen($turnus_string) > 70) {
            $turnus_string = htmlReady(mb_substr($turnus_string, 0, mb_strpos(mb_substr($turnus_string, 70, mb_strlen($turnus_string)), ',') + 71));
            $turnus_string .= ' ... <a href="' . URLHelper::getURL("dispatch.php/course/details/index/{$course->id}") . '">(' . _('mehr') . ')</a>';
        } else {
            $turnus_string = htmlReady($turnus_string);
        }
        $lecturers = $course->getMembersWithStatus('dozent');
        $semester = $course->start_semester;

        // If you are not root, perhaps not all available subcourses are visible.
        $visibleChildren = $course->children;
        if (!$GLOBALS['perm']->have_perm(Config::get()->SEM_VISIBILITY_PERM)) {
            $visibleChildren = $visibleChildren->filter(function($c) {
                return $c->visible;
            });
        }
        $result_children = [];
        foreach($visibleChildren as $child) {
            $result_children[] = self::filter($child, $search);
        }

        //admission state
        $admission_state = "";
        if (Config::get()->COURSE_SEARCH_SHOW_ADMISSION_STATE) {
            switch (self::getStatusCourseAdmission($course->id,
                $course->admission_prelim)) {
                case 1:
                    $admission_state = Icon::create(
                        'decline-circle',
                        Icon::ROLE_STATUS_YELLOW,
                        tooltip2(_('Eingeschränkter Zugang'))
                    )->asImg();
                    break;
                case 2:
                    $admission_state = Icon::create(
                        'decline-circle',
                        Icon::ROLE_STATUS_RED,
                        tooltip2(_('Kein Zugang'))
                    )->asImg();
                    break;
                default:
                    $admission_state = Icon::create(
                        'check-circle',
                        Icon::ROLE_STATUS_GREEN,
                        tooltip2(_('Uneingeschränkter Zugang'))
                    )->asImg();
            }
        }

        $tags = array_map(function ($t) {
            return '#' . $t->name;
        }, $course->tags->getArrayCopy());

        $result = [
            'id'            => $course->id,
            'number'        => self::mark($course->veranstaltungsnummer, $search),
            'name'          => self::mark($course->getFullName(), $search),
            'url'           => URLHelper::getURL("dispatch.php/course/details/index/{$course->id}", [], true),
            'date'          => htmlReady($semester->short_name),
            'dates'         => $turnus_string,
            'has_children'  => count($course->children) > 0,
            'children'      => $result_children,
            'additional'    => implode(', ',
                array_filter(
                    array_map(
                        function ($lecturer, $index) use ($search, $course) {
                            if ($index < 3) {
                                return self::mark($lecturer->getUserFullname(), $search);
                            } else if ($index == 3) {
                                return '... (' . _('mehr') . ')';
                            }
                        },
                        $lecturers,
                        array_keys($lecturers)
                    )
                )
            ),
            'expand'            => self::getSearchURL($search),
            'admission_state'   => $admission_state,
            'found_tag'         => self::mark(implode(' ', $tags), $search)
        ];
        if ($course->getSemClass()->offsetGet('studygroup_mode')) {
            $avatar = StudygroupAvatar::getAvatar($course->id);
        } else {
            $avatar = CourseAvatar::getAvatar($course->id);
        }
        $result['img'] = $avatar->getUrl(Avatar::MEDIUM);
        return $result;
    }

    /**
     * Enables fulltext (MATCH AGAINST) search by creating the corresponding indices.
     */
    public static function enable()
    {
        DBManager::get()->exec("ALTER TABLE `seminare` ADD FULLTEXT INDEX globalsearch (`VeranstaltungsNummer`, `Name`)");
        DBManager::get()->exec("ALTER TABLE `sem_types` ADD FULLTEXT INDEX globalsearch (`Name`)");
    }

    /**
     * Disables fulltext (MATCH AGAINST) search by removing the corresponding indices.
     */
    public static function disable()
    {
        DBManager::get()->exec("DROP INDEX globalsearch ON `seminare`");
        DBManager::get()->exec("DROP INDEX globalsearch ON `sem_types`");
    }

    /**
     * Returns the URL that can be called for a full search.
     *
     * @param string $searchterm what to search for?
     * @return string URL to the full search, containing the searchterm and the category
     */
    public static function getSearchURL($searchterm): string
    {
        return URLHelper::getURL('dispatch.php/search/globalsearch', [
            'q'        => $searchterm,
            'category' => self::class
        ]);
    }

    /**
     * Returns the admission status for a course.
     *
     * @param string $seminar_id Id of the course
     * @param bool   $prelim     State of preliminary setting
     * @return int
     */
    public static function getStatusCourseAdmission($seminar_id, $prelim): int
    {
        $sql = "SELECT COUNT(`type`) AS `types`,
                       SUM(IF(`type` = 'LockedAdmission', 1, 0)) AS `type_locked`
                FROM `seminar_courseset`
	            INNER JOIN `courseset_rule` USING (`set_id`)
	            WHERE `seminar_id` = ?
                GROUP BY `set_id`";

        $stmt = DBManager::get()->prepare($sql);
        $stmt->execute([$seminar_id]);
        $result = $stmt->fetch();

        if (!empty($result['types'])) {
            if ($result['type_locked']) {
                return 2;
            }
            return 1;
        }

        if ($prelim) {
            return 1;
        }
        return 0;
    }

}