chamilo-lms2/main/inc/lib/groupmanager.lib.php

<?php
/* For licensing terms, see /license.txt */
/**
 *
 * @package chamilo.library
 */
/**
 * Code
 */

/**
 * This library contains some functions for group-management.
 * @author Bart Mollet
 * @package chamilo.library
 * @todo Add $course_code parameter to all functions. So this GroupManager can
 * be used outside a session.
 */
class GroupManager
{
    //- VIRTUAL_COURSE_CATEGORY: in this category groups are created based on the virtual  course of a course
    CONST VIRTUAL_COURSE_CATEGORY = 1;

    //DEFAULT_GROUP_CATEGORY: When group categories aren't available (platform-setting),  all groups are created in this 'dummy'-category
    CONST DEFAULT_GROUP_CATEGORY = 2;

    /**
     * infinite
     */
    CONST INFINITE = 99999;
    /**
     * No limit on the number of users in a group
     */
    CONST MEMBER_PER_GROUP_NO_LIMIT = 0;
    /**
     * No limit on the number of groups per user
     */
    CONST GROUP_PER_MEMBER_NO_LIMIT = 0;
    /**
     * The tools of a group can have 3 states
     * - not available
     * - public
     * - private
     */
    CONST TOOL_NOT_AVAILABLE = 0;
    CONST TOOL_PUBLIC = 1;
    CONST TOOL_PRIVATE = 2;
    /**
     * Constants for the available group tools
     */
    CONST GROUP_TOOL_FORUM = 0;
    CONST GROUP_TOOL_DOCUMENTS = 1;
    CONST GROUP_TOOL_CALENDAR = 2;
    CONST GROUP_TOOL_ANNOUNCEMENT = 3;
    CONST GROUP_TOOL_WORK = 4;
    CONST GROUP_TOOL_WIKI = 5;
    CONST GROUP_TOOL_CHAT = 6;

    //GROUP FUNCTIONS
    private function __construct()
    {
    }

    public static function get_groups()
    {
        $table_group = Database :: get_course_table(TABLE_GROUP);
        $course_id = api_get_course_int_id();

        $sql = "SELECT * FROM $table_group WHERE c_id = $course_id ";
        $result = Database::query($sql);

        return Database::store_result($result, 'ASSOC');
    }

    /**
     * Get list of groups for current course.
     * @param int $category The id of the category from which the groups are
     * requested
     * @param string $course_code Default is current course
     * @return array An array with all information about the groups.
     */
    public static function get_group_list($category = null, $course_code = null)
    {
        $my_user_id = api_get_user_id();
        $course_info = api_get_course_info($course_code);
        $course_id = $course_info['real_id'];
        $table_group_user = Database :: get_course_table(TABLE_GROUP_USER);
        $table_group = Database :: get_course_table(TABLE_GROUP);

        //condition for the session
        $session_id = api_get_session_id();
        $my_status_of_user_in_course = CourseManager::get_user_in_course_status($my_user_id, $course_info['code']);

        $is_student_in_session = false;
        // User is subscribed in session
        if (is_null($my_status_of_user_in_course) || $my_status_of_user_in_course == '') {
            if ($session_id > 0) {
                $is_student_in_session = true;
            }
        }
        $sql = null;

        // @todo fix the conditions below

        // COURSEMANAGER or STUDENT
        if ($my_status_of_user_in_course == COURSEMANAGER || api_is_allowed_to_edit(null, true) || api_is_drh()) {
            $sql = "SELECT g.id ,
						g.name ,
						g.description ,
						g.category_id,
						g.max_student maximum_number_of_members,
						g.secret_directory,
						g.self_registration_allowed,
						g.self_unregistration_allowed,
						g.session_id,
						ug.user_id is_member
					FROM $table_group g
					LEFT JOIN $table_group_user ug
					ON (ug.group_id = g.id AND ug.user_id = '".api_get_user_id(
            )."' AND ug.c_id = $course_id AND g.c_id = $course_id)";
        } elseif ($my_status_of_user_in_course == STUDENT || $is_student_in_session === true) {
            $sql = "SELECT g.id,
						g.name,
						g.description,
						g.category_id,
						g.max_student maximum_number_of_members,
						g.secret_directory,
						g.self_registration_allowed,
						g.self_unregistration_allowed,
						g.session_id,
						ug.user_id is_member
					FROM $table_group g
					LEFT JOIN $table_group_user ug
					ON (ug.group_id = g.id AND
					    ug.user_id = '".api_get_user_id()."' AND
					    ug.c_id = $course_id AND
					    g.c_id = $course_id )";
        }

        if (empty($sql)) {
            return array();
        }

        $sql .= " WHERE 1=1 ";

        if ($category != null) {
            $sql .= "  AND  g.category_id = '".Database::escape_string($category)."' ";
            $session_condition = api_get_session_condition($session_id);
            if (!empty($session_condition)) {
                $sql .= $session_condition;
            }
        } else {
            $session_condition = api_get_session_condition($session_id, true);
        }

        $sql .= " AND g.c_id = $course_id ";

        if (!empty($session_condition)) {
            $sql .= $session_condition;
        }
        $sql .= " GROUP BY g.id ORDER BY UPPER(g.name)";

        if (!api_is_anonymous()) {
            $groupList = Database::query($sql);
        } else {
            return array();
        }

        $groups = array();

        while ($thisGroup = Database::fetch_array($groupList)) {
            $thisGroup['number_of_members'] = count(self::get_subscribed_users($thisGroup['id']));

            if ($thisGroup['session_id'] != 0) {
                $sql_session = 'SELECT name FROM '.Database::get_main_table(TABLE_MAIN_SESSION).'
                                WHERE id='.$thisGroup['session_id'];
                $rs_session = Database::query($sql_session);
                if (Database::num_rows($rs_session) > 0) {
                    $thisGroup['session_name'] = Database::result($rs_session, 0, 0);
                } else {
                    //the session has probably been removed, so the group is now orphaned
                }
            }
            $groups[] = $thisGroup;
        }

        return $groups;
    }

    /**
     * Create a group
     * @param string $name The name for this group
     * @param int $tutor The user-id of the group's tutor
     * @param int $places How many people can subscribe to the new group
     */
    public static function create_group($name, $category_id, $tutor, $places)
    {
        $_course = api_get_course_info();
        $table_group = Database :: get_course_table(TABLE_GROUP);

        $session_id = api_get_session_id();
        $course_id = api_get_course_int_id();
        $currentCourseRepository = $_course['path'];

        $category = self :: get_category($category_id);

        if (intval($places) == 0) {
            //if the amount of users per group is not filled in, use the setting from the category
            $places = $category['max_student'];
        } else {
            if ($places > $category['max_student'] && $category['max_student'] != 0) {
                $places = $category['max_student'];
            }
        }

        $sql = "INSERT INTO ".$table_group." SET
				c_id = $course_id ,
				category_id='".Database::escape_string($category_id)."',
				max_student = '".$places."',
				doc_state = '".$category['doc_state']."',
				calendar_state = '".$category['calendar_state']."',
				work_state = '".$category['work_state']."',
				announcements_state = '".$category['announcements_state']."',
				forum_state = '".$category['forum_state']."',
				wiki_state = '".$category['wiki_state']."',
				chat_state = '".$category['chat_state']."',
				self_registration_allowed = '".$category['self_reg_allowed']."',
				self_unregistration_allowed = '".$category['self_unreg_allowed']."',
				session_id='".Database::escape_string($session_id)."'";

        Database::query($sql);
        $lastId = Database::insert_id();

        //Fixing Id
        Database::update($table_group, array('id' => $lastId), array('iid = ? ' => $lastId));

        if ($lastId) {
            $desired_dir_name = '/'.api_replace_dangerous_char($name, 'strict').'_groupdocs';
            $my_path = api_get_path(SYS_COURSE_PATH).$currentCourseRepository.'/document';
            $unique_name = FileManager::create_unexisting_directory(
                $_course,
                api_get_user_id(),
                $session_id,
                $lastId,
                null,
                $my_path,
                $desired_dir_name
            );

            /* Stores the directory path into the group table */
            $sql = "UPDATE ".$table_group." SET name = '".Database::escape_string(
                $name
            )."', secret_directory = '".$unique_name."'
                    WHERE c_id = $course_id AND id ='".$lastId."'";

            Database::query($sql);

            // create a forum if needed
            if ($category['forum_state'] >= 0) {
                require_once api_get_path(SYS_CODE_PATH).'forum/forumconfig.inc.php';
                require_once api_get_path(SYS_CODE_PATH).'forum/forumfunction.inc.php';

                $forum_categories = get_forum_categories();

                $values = array();
                $values['forum_title'] = $name;
                $values['group_id'] = $lastId;

                $counter = 0;
                foreach ($forum_categories as $key => $value) {
                    if ($counter == 0) {
                        $forum_category_id = $key;
                    }
                    $counter++;
                }
                // A sanity check.
                if (empty($forum_category_id)) {
                    $forum_category_id = 0;
                }
                $values['forum_category'] = $forum_category_id;
                $values['allow_anonymous_group']['allow_anonymous'] = 0;
                $values['students_can_edit_group']['students_can_edit'] = 0;
                $values['approval_direct_group']['approval_direct'] = 0;
                $values['allow_attachments_group']['allow_attachments'] = 1;
                $values['allow_new_threads_group']['allow_new_threads'] = 1;
                $values['default_view_type_group']['default_view_type'] = api_get_setting('default_forum_view');
                $values['group_forum'] = $lastId;
                if ($category['forum_state'] == '1') {
                    $values['public_private_group_forum_group']['public_private_group_forum'] = 'public';
                } elseif ($category['forum_state'] == '2') {
                    $values['public_private_group_forum_group']['public_private_group_forum'] = 'private';
                } elseif ($category['forum_state'] == '0') {
                    $values['public_private_group_forum_group']['public_private_group_forum'] = 'unavailable';
                }
                store_forum($values);
            }
        }

        return $lastId;
    }

    /**
     * Create subgroups.
     * This function creates new groups based on an existing group. It will
     * create the specified number of groups and fill those groups with users
     * from the base group
     * @param int $group_id The group from which subgroups have to be created.
     * @param int $number_of_groups The number of groups that have to be created
     */
    public static function create_subgroups($group_id, $number_of_groups)
    {
        $course_id = api_get_course_int_id();
        $table_group = Database :: get_course_table(TABLE_GROUP);
        $category_id = self :: create_category('Subgroups', '', self::TOOL_PRIVATE, self::TOOL_PRIVATE, 0, 0, 1, 1);
        $users = self :: get_users($group_id);
        $group_ids = array();

        for ($group_nr = 1; $group_nr <= $number_of_groups; $group_nr++) {
            $group_ids[] = self :: create_group('SUBGROUP '.$group_nr, $category_id, 0, 0);
        }
        $members = array();
        foreach ($users as $index => $user_id) {
            self :: subscribe_users($user_id, $group_ids[$index % $number_of_groups]);
            $members[$group_ids[$index % $number_of_groups]]++;
        }
        foreach ($members as $group_id => $places) {
            $sql = "UPDATE $table_group SET max_student = $places WHERE c_id = $course_id  AND id = $group_id";
            Database::query($sql);
        }
    }

    /**
     * Create a group for every class subscribed to the current course
     * @param int $category_id The category in which the groups should be
     * created
     */
    public static function create_class_groups($category_id)
    {
        $_course = api_get_course_info();
        $options['where'] = array(" usergroup.course_id = ? " => api_get_real_course_id());
        $obj = new UserGroup();
        $classes = $obj->get_usergroup_in_course($options);
        $group_ids = array();
        foreach ($classes as $index => $class) {
            $users_ids = $obj->get_users_by_usergroup($class['id']);
            $group_id = self::create_group($class['name'], $category_id, 0, count($users_ids));
            self::subscribe_users($users_ids, $group_id);
            $group_ids[] = $group_id;
        }

        return $group_ids;
    }

    /**
     * deletes groups and their data.
     * @author Christophe Gesche <christophe.gesche@claroline.net>
     * @author Hugues Peeters <hugues.peeters@claroline.net>
     * @author Bart Mollet
     * @param  mixed   $groupIdList - group(s) to delete. It can be a single id
     *                                (int) or a list of id (array).
     * @param string $course_code Default is current course
     * @return integer              - number of groups deleted.
     */
    public static function delete_groups($group_ids, $course_code = null)
    {
        $course_info = api_get_course_info($course_code);
        $course_id = $course_info['real_id'];

        // Database table definitions
        $group_table = Database :: get_course_table(TABLE_GROUP);
        $forum_table = Database :: get_course_table(TABLE_FORUM);

        $group_ids = is_array($group_ids) ? $group_ids : array($group_ids);
        $group_ids = array_map('intval', $group_ids);

        if (api_is_course_coach()) {
            //a coach can only delete courses from his session
            for ($i = 0; $i < count($group_ids); $i++) {
                if (!api_is_element_in_the_session(TOOL_GROUP, $group_ids[$i])) {
                    array_splice($group_ids, $i, 1);
                    $i--;
                }
            }
            if (count($group_ids) == 0) {
                return 0;
            }
        }

        // Unsubscribe all users
        self :: unsubscribe_all_users($group_ids);
        $sql = "SELECT id, secret_directory, session_id FROM $group_table WHERE c_id = $course_id AND id IN (".implode(
            ' , ',
            $group_ids
        ).")";
        $db_result = Database::query($sql);
        $forum_ids = array();

        while ($group = Database::fetch_object($db_result)) {
            // move group-documents to garbage
            //$source_directory = api_get_path(SYS_COURSE_PATH).$course['path']."/group/".$group->secret_directory;
            $source_directory = api_get_path(SYS_COURSE_PATH).$course_info['path']."/document".$group->secret_directory;
            //File to renamed
            $destination_dir = api_get_path(
                SYS_COURSE_PATH
            ).$course_info['path']."/document".$group->secret_directory.'_DELETED_'.$group->id;

            if (!empty($group->secret_directory)) {
                //Deleting from document tool
                DocumentManager::delete_document($course_info, $group->secret_directory, $source_directory);

                if (file_exists($source_directory)) {
                    if (api_get_setting('permanently_remove_deleted_files') == 'true') {
                        //Delete
                        FileManager::my_delete($source_directory);
                    } else {
                        //Rename
                        rename($source_directory, $destination_dir);
                    }
                }
            }
            //$forum_ids[] = $group->forum_id;
        }

        // delete the groups
        $sql = "DELETE FROM ".$group_table." WHERE c_id = $course_id AND id IN ('".implode("' , '", $group_ids)."')";
        Database::query($sql);

        $sql2 = "DELETE FROM ".$forum_table." WHERE c_id = $course_id AND forum_of_group IN ('".implode(
            "' , '",
            $group_ids
        )."')";
        $result = Database::query($sql2);

        return Database::affected_rows($result);
    }

    /**
     * Get group properties
     * @param int $group_id The group from which properties are requested.
     * @return array All properties. Array-keys are name, tutor_id, description, maximum_number_of_students, directory and visibility of tools
     */
    public static function get_group_properties($group_id)
    {
        $course_id = api_get_course_int_id();
        if (empty($group_id) or !is_integer(intval($group_id))) {
            return null;
        }
        $result = array();

        $table_group = Database :: get_course_table(TABLE_GROUP);
        $sql = "SELECT * FROM $table_group WHERE c_id = $course_id AND id = ".intval($group_id);
        $db_result = Database::query($sql);
        $db_object = Database::fetch_object($db_result);

        $result['id'] = $db_object->id;
        $result['name'] = $db_object->name;
        $result['tutor_id'] = isset($db_object->tutor_id) ? $db_object->tutor_id : null;
        $result['description'] = $db_object->description;
        $result['maximum_number_of_students'] = $db_object->max_student;
        $result['doc_state'] = $db_object->doc_state;
        $result['work_state'] = $db_object->work_state;
        $result['calendar_state'] = $db_object->calendar_state;
        $result['announcements_state'] = $db_object->announcements_state;
        $result['forum_state'] = $db_object->forum_state;
        $result['wiki_state'] = $db_object->wiki_state;
        $result['chat_state'] = $db_object->chat_state;
        $result['directory'] = $db_object->secret_directory;
        $result['self_registration_allowed'] = $db_object->self_registration_allowed;
        $result['self_unregistration_allowed'] = $db_object->self_unregistration_allowed;

        $result['count_users'] = count(self::get_subscribed_users($group_id));
        $result['count_tutor'] = count(self::get_subscribed_tutors($group_id));
        $result['count_all'] = $result['count_users'] + $result['count_tutor'];

        return $result;
    }

    /**
     * Set group properties
     * Changes the group's properties.
     * @param int        Group Id
     * @param string     Group name
     * @param string    Group description
     * @param int        Max number of students in group
     * @param int        Document tool's visibility (0=none,1=private,2=public)
     * @param int        Work tool's visibility (0=none,1=private,2=public)
     * @param int        Calendar tool's visibility (0=none,1=private,2=public)
     * @param int        Announcement tool's visibility (0=none,1=private,2=public)
     * @param int        Forum tool's visibility (0=none,1=private,2=public)
     * @param int        Wiki tool's visibility (0=none,1=private,2=public)
     * @param int        Chat tool's visibility (0=none,1=private,2=public)
     * @param bool         Whether self registration is allowed or not
     * @param bool         Whether self unregistration is allowed or not
     * @return bool     TRUE if properties are successfully changed, false otherwise
     */
    public static function set_group_properties(
        $group_id,
        $name,
        $description,
        $maximum_number_of_students,
        $doc_state,
        $work_state,
        $calendar_state,
        $announcements_state,
        $forum_state,
        $wiki_state,
        $chat_state,
        $self_registration_allowed,
        $self_unregistration_allowed
    ) {
        $table_group = Database :: get_course_table(TABLE_GROUP);
        $table_forum = Database :: get_course_table(TABLE_FORUM);
        //$forum_id = get_forums_of_group($group_id);
        $group_id = Database::escape_string($group_id);
        $category = self::get_category_from_group($group_id);
        if ($maximum_number_of_students > $category['max_student'] && $category['max_student'] != 0) {
            $maximum_number_of_students = $category['max_student'];
        }
        $course_id = api_get_course_int_id();

        $sql = "UPDATE ".$table_group."
					SET name='".Database::escape_string(trim($name))."',
					doc_state = '".Database::escape_string($doc_state)."',
					work_state = '".Database::escape_string($work_state)."',
					calendar_state = '".Database::escape_string($calendar_state)."',
					announcements_state = '".Database::escape_string($announcements_state)."',
					forum_state = '".Database::escape_string($forum_state)."',
					wiki_state = '".Database::escape_string($wiki_state)."',
					chat_state = '".Database::escape_string($chat_state)."',
					description='".Database::escape_string(trim($description))."',
					max_student=".Database::escape_string($maximum_number_of_students).",
					self_registration_allowed='".Database::escape_string($self_registration_allowed)."',
					self_unregistration_allowed='".Database::escape_string($self_unregistration_allowed)."'
					WHERE c_id = $course_id AND id=".$group_id;
        $result = Database::query($sql);
        //Here we are updating a field in the table forum_forum that perhaps duplicates the table group_info.forum_state cvargas
        $forum_state = (int)$forum_state;
        $sql2 = "UPDATE ".$table_forum." SET ";
        if ($forum_state === 1) {
            $sql2 .= " forum_group_public_private='public' ";
        } elseif ($forum_state === 2) {
            $sql2 .= " forum_group_public_private='private' ";
        } elseif ($forum_state === 0) {
            $sql2 .= " forum_group_public_private='unavailable' ";
        }
        $sql2 .= " WHERE c_id = 	$course_id AND forum_of_group=".$group_id;
        $result2 = Database::query($sql2);

        return $result;
    }

    /**
     * Get the total number of groups for the current course.
     * @return int The number of groups for the current course.
     */
    public static function get_number_of_groups()
    {
        $course_id = api_get_course_int_id();
        $table_group = Database :: get_course_table(TABLE_GROUP);
        $res = Database::query("SELECT COUNT(id) AS number_of_groups FROM $table_group WHERE c_id = $course_id ");
        $obj = Database::fetch_object($res);

        return $obj->number_of_groups;
    }

    //GROUPCATEGORY FUNCTIONS

    /**
     * Get all categories
     * @param string $course_code The cours (default = current course)
     */
    public static function get_categories($course_code = null)
    {
        $course_info = api_get_course_info($course_code);
        $course_id = $course_info['real_id'];
        $table_group_cat = Database :: get_course_table(TABLE_GROUP_CATEGORY);
        $sql = "SELECT * FROM $table_group_cat WHERE c_id = $course_id ORDER BY display_order";
        $res = Database::query($sql);
        $cats = array();
        while ($cat = Database::fetch_array($res)) {
            $cats[] = $cat;
        }

        return $cats;
    }

    /**
     * Get a group category
     * @param int $id The category id
     * @param string $course_code The course (default = current course)
     */
    public static function get_category($id, $course_code = null)
    {
        if (empty($id)) {
            return array();
        }
        $course_info = api_get_course_info($course_code);
        $course_id = $course_info['real_id'];
        $id = Database::escape_string($id);
        $table_group_cat = Database :: get_course_table(TABLE_GROUP_CATEGORY);
        $sql = "SELECT * FROM $table_group_cat WHERE c_id = $course_id AND id = $id LIMIT 1";
        $res = Database::query($sql);

        return Database::fetch_array($res);
    }

    /**
     * Get the unique category of a given group
     * @param int $group_id The id of the group
     * @param string $course_code The course in which the group is (default =
     * current course)
     * @return array The category
     */
    public static function get_category_from_group($group_id, $course_code = null)
    {
        $table_group = Database :: get_course_table(TABLE_GROUP);
        $table_group_cat = Database :: get_course_table(TABLE_GROUP_CATEGORY);

        if (empty($group_id)) {
            return array();
        }

        $course_info = api_get_course_info($course_code);
        $course_id = $course_info['real_id'];

        $group_id = Database::escape_string($group_id);
        $sql = "SELECT gc.* FROM $table_group_cat gc, $table_group g
				WHERE 	gc.c_id = $course_id AND
						g.c_id = $course_id AND
						gc.id = g.category_id AND g.id= $group_id LIMIT 1";
        $res = Database::query($sql);
        $cat = array();
        if (Database::num_rows($res)) {
            $cat = Database::fetch_array($res);
        }

        return $cat;
    }

    /**
     * Delete a group category
     * @param int $cat_id The id of the category to delete
     * @param string $course_code The code in which the category should be
     * deleted (default = current course)
     */
    public static function delete_category($cat_id, $course_code = null)
    {
        $course_info = api_get_course_info($course_code);
        $course_id = $course_info['real_id'];

        $table_group = Database :: get_course_table(TABLE_GROUP);
        $table_group_cat = Database :: get_course_table(TABLE_GROUP_CATEGORY);
        $cat_id = Database::escape_string($cat_id);
        $sql = "SELECT id FROM $table_group WHERE c_id = $course_id AND category_id='".$cat_id."'";
        $res = Database::query($sql);
        if (Database::num_rows($res) > 0) {
            $groups_to_delete = array();
            while ($group = Database::fetch_object($res)) {
                $groups_to_delete[] = $group->id;
            }
            self :: delete_groups($groups_to_delete);
        }
        $sql = "DELETE FROM $table_group_cat WHERE c_id = $course_id  AND id='".$cat_id."'";
        Database::query($sql);
    }

    /**
     * Create group category
     * @param string $title The title of the new category
     * @param string $description The description of the new category
     * @param bool $self_registration_allowed
     * @param bool $self_unregistration_allowed
     * @param int $max_number_of_students
     * @param int $groups_per_user
     */
    public static function create_category(
        $title,
        $description,
        $doc_state,
        $work_state,
        $calendar_state,
        $announcements_state,
        $forum_state,
        $wiki_state,
        $chat_state = 1,
        $self_registration_allowed = 0,
        $self_unregistration_allowed = 0,
        $maximum_number_of_students = 8,
        $groups_per_user = 0
    ) {
        $table_group_category = Database :: get_course_table(TABLE_GROUP_CATEGORY);

        $course_id = api_get_course_int_id();

        $sql = "SELECT MAX(display_order)+1 as new_order FROM $table_group_category WHERE c_id = $course_id ";
        $res = Database::query($sql);
        $obj = Database::fetch_object($res);
        if (!isset ($obj->new_order)) {
            $obj->new_order = 1;
        }
        $sql = "INSERT INTO ".$table_group_category." SET
					c_id =  $course_id ,
					title='".Database::escape_string($title)."',
					display_order ='".$obj->new_order."',
					description='".Database::escape_string($description)."',
					doc_state = '".Database::escape_string($doc_state)."',
					work_state = '".Database::escape_string($work_state)."',
					calendar_state = '".Database::escape_string($calendar_state)."',
              		announcements_state = '".Database::escape_string($announcements_state)."',
              		forum_state = '".Database::escape_string($forum_state)."',
					wiki_state = '".Database::escape_string($wiki_state)."',
					chat_state = '".Database::escape_string($chat_state)."',
					groups_per_user   = '".Database::escape_string($groups_per_user)."',
					self_reg_allowed = '".Database::escape_string($self_registration_allowed)."',
					self_unreg_allowed = '".Database::escape_string($self_unregistration_allowed)."',
					max_student = '".Database::escape_string($maximum_number_of_students)."' ";
        Database::query($sql);
        $id = Database::insert_id();
        if ($id == self::VIRTUAL_COURSE_CATEGORY) {
            $sql = "UPDATE  ".$table_group_category." SET id = ".($id + 1)." WHERE c_id = $course_id AND id = $id";
            Database::query($sql);

            return $id + 1;
        }

        return $id;
    }

    /**
     * Update group category
     * @param int $id The id of the category
     * @param string $title The title of the new category
     * @param string $description The description of the new category
     * @param bool $self_registration_allowed
     * @param bool $self_unregistration_allowed
     * @param int $max_number_of_students
     * @param int $groups_per_user
     */
    public static function update_category(
        $id,
        $title,
        $description,
        $doc_state,
        $work_state,
        $calendar_state,
        $announcements_state,
        $forum_state,
        $wiki_state,
        $chat_state,
        $self_registration_allowed,
        $self_unregistration_allowed,
        $maximum_number_of_students,
        $groups_per_user
    ) {
        $table_group_category = Database :: get_course_table(TABLE_GROUP_CATEGORY);
        $id = Database::escape_string($id);

        $course_id = api_get_course_int_id();

        $sql = "UPDATE ".$table_group_category."
				SET title='".Database::escape_string($title)."',
				description='".Database::escape_string($description)."',
				doc_state = '".Database::escape_string($doc_state)."',
				work_state = '".Database::escape_string($work_state)."',
            	calendar_state = '".Database::escape_string($calendar_state)."',
            	announcements_state = '".Database::escape_string($announcements_state)."',
            	forum_state = '".Database::escape_string($forum_state)."',
				wiki_state = '".Database::escape_string($wiki_state)."',
				chat_state = '".Database::escape_string($chat_state)."',
				groups_per_user   = ".Database::escape_string($groups_per_user).",
				self_reg_allowed = '".Database::escape_string($self_registration_allowed)."',
				self_unreg_allowed = '".Database::escape_string($self_unregistration_allowed)."',
				max_student = ".Database::escape_string($maximum_number_of_students)."
				WHERE c_id = $course_id AND id=$id";
        Database::query($sql);
    }


    /**
     * Returns the number of groups of the user with the greatest number of
     * subscribtions in the given category
     */
    public static function get_current_max_groups_per_user($category_id = null, $course_code = null)
    {
        $course_info = api_get_course_info($course_code);
        $group_table = Database :: get_course_table(TABLE_GROUP);
        $group_user_table = Database :: get_course_table(TABLE_GROUP_USER);
        $sql = 'SELECT COUNT(gu.group_id) AS current_max FROM '.$group_user_table.' gu, '.$group_table.' g
				WHERE g.c_id = '.$course_info['real_id'].' AND gu.group_id = g.id ';
        if ($category_id != null) {
            $category_id = Database::escape_string($category_id);
            $sql .= ' AND g.category_id = '.$category_id;
        }
        $sql .= ' GROUP BY gu.user_id ORDER BY current_max DESC LIMIT 1';
        $res = Database::query($sql);
        $obj = Database::fetch_object($res);

        return $obj->current_max;
    }

    /**
     * Swaps the display-order of two categories
     * @param int $id1 The id of the first category
     * @param int $id2 The id of the second category
     */
    public static function swap_category_order($id1, $id2)
    {
        $table_group_cat = Database :: get_course_table(TABLE_GROUP_CATEGORY);
        $id1 = Database::escape_string($id1);
        $id2 = Database::escape_string($id2);

        $course_id = api_get_course_int_id();


        $sql = "SELECT id,display_order FROM $table_group_cat WHERE id IN ($id1,$id2) AND c_id = $course_id ";
        $res = Database::query($sql);
        $cat1 = Database::fetch_object($res);
        $cat2 = Database::fetch_object($res);
        $sql = "UPDATE $table_group_cat SET display_order=$cat2->display_order WHERE id = $cat1->id AND c_id = $course_id ";
        Database::query($sql);
        $sql = "UPDATE $table_group_cat SET display_order=$cat1->display_order WHERE id = $cat2->id AND c_id = $course_id ";
        Database::query($sql);
    }

    //GROUP USERS FUNCTIONS

    /**
     * Get all users from a given group
     * @param int $group_id The group
     * @return array list of user id
     */
    public static function get_users($group_id, $load_extra_info = false, $course_id = null)
    {
        $group_user_table = Database :: get_course_table(TABLE_GROUP_USER);
        $group_id = Database::escape_string($group_id);
        if (empty($course_id)) {
            $course_id = api_get_course_int_id();
        } else {
            $course_id = intval($course_id);
        }
        $sql = "SELECT user_id FROM $group_user_table WHERE c_id = $course_id AND group_id = $group_id";
        $res = Database::query($sql);
        $users = array();
        while ($obj = Database::fetch_object($res)) {
            if ($load_extra_info) {
                $users[] = api_get_user_info($obj->user_id);
            } else {
                $users[] = $obj->user_id;
            }
        }

        return $users;
    }

    /**
     * @param int $group_id
     * @return array
     */
    public static function get_members_and_tutors($group_id)
    {
        $group_user_table = Database :: get_course_table(TABLE_GROUP_USER);
        $tutor_user_table = Database :: get_course_table(TABLE_GROUP_TUTOR);
        $course_id = api_get_course_int_id();
        $group_id = intval($group_id);
        $sql = "SELECT user_id FROM $group_user_table WHERE c_id = $course_id AND group_id = $group_id";
        $res = Database::query($sql);
        $users = array();

        while ($obj = Database::fetch_object($res)) {
            $users[] = api_get_user_info($obj->user_id);
        }

        $sql = "SELECT user_id FROM $tutor_user_table WHERE c_id = $course_id AND group_id = $group_id";
        $res = Database::query($sql);
        while ($obj = Database::fetch_object($res)) {
            $users[] = api_get_user_info($obj->user_id);
        }

        return $users;
    }

    /**
     * Returns users belonging to any of the group
     *
     * @param array $groups list of group ids
     * @return array list of user ids
     */
    public static function get_groups_users($groups = array())
    {
        $result = array();
        $tbl_group_user = Database::get_course_table(TABLE_GROUP_USER);
        $course_id = api_get_course_int_id();

        $groups = array_map('intval', $groups);
        $groups = implode(', ', $groups); //protect individual elements with surrounding quotes
        $sql = "SELECT DISTINCT user_id
                FROM $tbl_group_user gu
                WHERE c_id = $course_id AND gu.group_id IN ($groups)";
        $rs = Database::query($sql);
        while ($row = Database::fetch_array($rs)) {
            $result[] = $row['user_id'];
        }

        return $result;
    }

    /**
     * Fill the groups with students.
     * The algorithm takes care to first fill the groups with the least # of users.
     *    Analysis
     *    There was a problem with the "ALL" setting.
     *    When max # of groups is set to all, the value is sometimes NULL and sometimes ALL
     *    and in both cased the query does not work as expected.
     *    Stupid solution (currently implemented: set ALL to a big number (INFINITE) and things are solved :)
     *    Better solution: that's up to you.
     *
     *    Note
     *    Throughout Dokeos there is some confusion about "course id" and "course code"
     *    The code is e.g. TEST101, but sometimes a variable that is called courseID also contains a course code string.
     *    However, there is also a integer course_id that uniquely identifies the course.
     *    ywarnier:> Now the course_id has been removed (25/1/2005)
     *    The databases are als very inconsistent in this.
     *
     * @author Chrisptophe Gesche <christophe.geshe@claroline.net>,
     *         Hugues Peeters     <hugues.peeters@claroline.net> - original version
     * @author Roan Embrechts - virtual course support, code cleaning
     * @author Bart Mollet - code cleaning, use other GroupManager-functions
     * @return void
     */
    public static function fill_groups($group_ids)
    {
        $_course = api_get_course_info();

        $group_ids = is_array($group_ids) ? $group_ids : array($group_ids);
        $group_ids = array_map('intval', $group_ids);

        if (api_is_course_coach()) {
            for ($i = 0; $i < count($group_ids); $i++) {
                if (!api_is_element_in_the_session(TOOL_GROUP, $group_ids[$i])) {
                    array_splice($group_ids, $i, 1);
                    $i--;
                }
            }
            if (count($group_ids) == 0) {
                return false;
            }
        }

        $category = self::get_category_from_group($group_ids[0]);

        $groups_per_user = $category['groups_per_user'];
        $group_table = Database :: get_course_table(TABLE_GROUP);
        $group_user_table = Database :: get_course_table(TABLE_GROUP_USER);
        $session_id = api_get_session_id();

        $complete_user_list = CourseManager :: get_real_and_linked_user_list($_course['code'], true, $session_id);
        $number_groups_per_user = ($groups_per_user == self::GROUP_PER_MEMBER_NO_LIMIT ? self::INFINITE : $groups_per_user);

        /*
         * Retrieve all the groups where enrollment is still allowed
         * (reverse) ordered by the number of place available
         */

        $course_id = api_get_course_int_id();
        $sql = "SELECT g.id gid, g.max_student-count(ug.user_id) nbPlaces, g.max_student
				FROM ".$group_table." g
				LEFT JOIN  ".$group_user_table." ug ON
                    g.c_id = $course_id AND ug.c_id = $course_id  AND g.id = ug.group_id
				WHERE
					g.id IN (".implode(',', $group_ids).")
				GROUP BY (g.id)
				HAVING (nbPlaces > 0 OR g.max_student = ".self::MEMBER_PER_GROUP_NO_LIMIT.")
				ORDER BY nbPlaces DESC";
        $sql_result = Database::query($sql);
        $group_available_place = array();
        while ($group = Database::fetch_array($sql_result, 'ASSOC')) {
            $group_available_place[$group['gid']] = $group['nbPlaces'];
        }

        /*
         * Retrieve course users (reverse) ordered by the number
         * of group they are already enrolled
         */
        for ($i = 0; $i < count($complete_user_list); $i++) {
            //find # of groups the user is enrolled in
            $number_of_groups = self :: user_in_number_of_groups($complete_user_list[$i]["user_id"], $category['id']);
            //add # of groups to user list
            $complete_user_list[$i]['number_groups_left'] = $number_groups_per_user - $number_of_groups;
        }

        //first sort by user_id to filter out duplicates
        $complete_user_list = TableSort :: sort_table($complete_user_list, 'user_id');
        $complete_user_list = self :: filter_duplicates($complete_user_list, 'user_id');
        $complete_user_list = self :: filter_only_students($complete_user_list);

        //now sort by # of group left
        $complete_user_list = TableSort :: sort_table($complete_user_list, 'number_groups_left', SORT_DESC);
        $userToken = array();
        foreach ($complete_user_list as $this_user) {
            if ($this_user['number_groups_left'] > 0) {
                $userToken[$this_user['user_id']] = $this_user['number_groups_left'];
            }
        }

        $changed = true;
        while ($changed) {
            $changed = false;
            reset($group_available_place);
            arsort($group_available_place);
            reset($userToken);
            arsort($userToken);

            foreach ($group_available_place as $group_id => $place) {
                foreach ($userToken as $user_id => $places) {
                    if (self :: can_user_subscribe($user_id, $group_id)) {

                        self :: subscribe_users($user_id, $group_id);
                        $group_available_place[$group_id]--;
                        //$userToken[$user_id]--;
                        unset($userToken[$user_id]);
                        $changed = true;
                        break;
                    }
                }
                if ($changed) {
                    break;
                }
            }
        }
    }


    /**
     * Get the number of students in a group.
     * @param int $group_id
     * @return int Number of students in the given group.
     */
    public static function number_of_students($group_id, $course_id = null)
    {
        $table_group_user = Database :: get_course_table(TABLE_GROUP_USER);
        $group_id = Database::escape_string($group_id);
        if (empty($course_id)) {
            $course_id = api_get_course_int_id();
        } else {
            $course_id = intval($course_id);
        }
        $sql = "SELECT  COUNT(*) AS number_of_students FROM $table_group_user WHERE c_id = $course_id AND group_id = $group_id";
        $db_result = Database::query($sql);
        $db_object = Database::fetch_object($db_result);

        return $db_object->number_of_students;
    }

    /**
     * Maximum number of students in a group
     * @param int $group_id
     * @return int Maximum number of students in the given group.
     */
    public static function maximum_number_of_students($group_id)
    {
        $table_group = Database :: get_course_table(TABLE_GROUP);
        $group_id = Database::escape_string($group_id);
        $course_id = api_get_course_int_id();
        $db_result = Database::query("SELECT max_student FROM $table_group WHERE c_id = $course_id AND id = $group_id");
        $db_object = Database::fetch_object($db_result);
        if ($db_object->max_student == 0) {
            return self::INFINITE;
        }

        return $db_object->max_student;
    }

    /**
     * Number of groups of a user
     * @param int $user_id
     * @return int The number of groups the user is subscribed in.
     */
    public static function user_in_number_of_groups($user_id, $cat_id = null)
    {
        $table_group_user = Database :: get_course_table(TABLE_GROUP_USER);
        $table_group = Database :: get_course_table(TABLE_GROUP);
        $user_id = Database::escape_string($user_id);
        $cat_id = Database::escape_string($cat_id);

        $course_id = api_get_course_int_id();
        $cat_condition = '';
        if (!empty($cat_id)) {
            $cat_condition = " AND g.category_id =  $cat_id ";
        }

        $sql = "SELECT  COUNT(*) AS number_of_groups FROM $table_group_user gu, $table_group g
				WHERE 	gu.c_id 	= $course_id AND
						g.c_id 		= $course_id AND
						gu.user_id 	= $user_id AND
						g.id 		= gu.group_id  $cat_condition";
        $db_result = Database::query($sql);
        $db_object = Database::fetch_object($db_result);

        return $db_object->number_of_groups;
    }

    /**
     * Is sef-registration allowed?
     * @param int $user_id
     * @param int $group_id
     * @return bool TRUE if self-registration is allowed in the given group.
     */
    public static function is_self_registration_allowed($user_id, $group_id)
    {
        $course_id = api_get_course_int_id();
        if (!$user_id > 0) {
            return false;
        }
        $table_group = Database :: get_course_table(TABLE_GROUP);
        $group_id = intval($group_id);
        if (isset($group_id)) {
            $sql = "SELECT  self_registration_allowed FROM $table_group WHERE c_id = $course_id AND id = $group_id";
            $db_result = Database::query($sql);
            $db_object = Database::fetch_object($db_result);

            return $db_object->self_registration_allowed == 1 && self :: can_user_subscribe($user_id, $group_id);
        } else {
            return false;
        }
    }

    /**
     * Is sef-unregistration allowed?
     * @param int $user_id
     * @param int $group_id
     * @return bool TRUE if self-unregistration is allowed in the given group.
     */
    public static function is_self_unregistration_allowed($user_id, $group_id)
    {
        if (!$user_id > 0) {
            return false;
        }
        $table_group = Database :: get_course_table(TABLE_GROUP);
        $group_id = Database::escape_string($group_id);
        $course_id = api_get_course_int_id();
        $db_result = Database::query(
            'SELECT  self_unregistration_allowed FROM '.$table_group.' WHERE c_id = '.$course_id.' AND id = '.$group_id
        );
        $db_object = Database::fetch_object($db_result);

        return $db_object->self_unregistration_allowed == 1 && self :: can_user_unsubscribe($user_id, $group_id);
    }

    /**
     * Is user subscribed in group?
     * @param int $user_id
     * @param int $group_id
     * @return bool TRUE if given user is subscribed in given group
     */
    public static function is_subscribed($user_id, $group_id)
    {
        if (empty($user_id) or empty($group_id)) {
            return false;
        }
        $table_group_user = Database :: get_course_table(TABLE_GROUP_USER);
        $group_id = Database::escape_string($group_id);
        $user_id = Database::escape_string($user_id);
        $course_id = api_get_course_int_id();
        $sql = 'SELECT 1 FROM '.$table_group_user.' WHERE c_id = '.$course_id.' AND group_id = '.$group_id.' AND user_id = '.$user_id;
        $db_result = Database::query($sql);

        return Database::num_rows($db_result) > 0;
    }

    /**
     * Can a user subscribe to a specified group in a course
     * @param int $user_id
     * @param int $group_id
     * @return bool TRUE if given user  can be subscribed in given group
     */
    public static function can_user_subscribe($user_id, $group_id)
    {
        $category = self :: get_category_from_group($group_id);
        $result = !self :: is_subscribed($user_id, $group_id);
        $result &= (self :: number_of_students($group_id) < self :: maximum_number_of_students($group_id));
        if ($category['groups_per_user'] == self::GROUP_PER_MEMBER_NO_LIMIT) {
            $category['groups_per_user'] = self::INFINITE;
        }
        $result &= (self :: user_in_number_of_groups($user_id, $category['id']) < $category['groups_per_user']);
        $result &= !self :: is_tutor_of_group($user_id, $group_id);

        return $result;
    }

    /**
     * Can a user unsubscribe to a specified group in a course
     * @param int $user_id
     * @param int $group_id
     * @return bool TRUE if given user  can be unsubscribed from given group
     * @internal for now, same as GroupManager::is_subscribed($user_id,$group_id)
     */
    public static function can_user_unsubscribe($user_id, $group_id)
    {
        $result = self :: is_subscribed($user_id, $group_id);

        return $result;
    }

    /**
     * Get all subscribed users from a group
     * @param int $group_id
     * @return array An array with information of all users from the given group.
     *               (user_id, firstname, lastname, email)
     */
    public static function get_subscribed_users($group_id)
    {
        $table_user = Database :: get_main_table(TABLE_MAIN_USER);
        $table_group_user = Database :: get_course_table(TABLE_GROUP_USER);
        $order_clause = api_sort_by_first_name(
        ) ? ' ORDER BY u.firstname, u.lastname' : ' ORDER BY u.lastname, u.firstname';
        if (empty($group_id)) {
            return array();
        }
        $group_id = intval($group_id);
        $course_id = api_get_course_int_id();

        $sql = "SELECT ug.id, u.user_id, u.lastname, u.firstname, u.email, u.username
				FROM  $table_user u INNER JOIN $table_group_user ug ON (ug.user_id = u.user_id)
				WHERE ug.c_id = $course_id AND
					  ug.group_id = $group_id
                $order_clause";
        $db_result = Database::query($sql);
        $users = array();
        while ($user = Database::fetch_object($db_result)) {
            $member['user_id'] = $user->user_id;
            $member['firstname'] = $user->firstname;
            $member['lastname'] = $user->lastname;
            $member['email'] = $user->email;
            $member['username'] = $user->username;
            $users[$member['user_id']] = $member;
        }

        return $users;
    }

    /**
     * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
     * Get all subscribed tutors of a group
     * @param int $group_id
     * @return array An array with information of all users from the given group.
     *               (user_id, firstname, lastname, email)
     */
    public static function get_subscribed_tutors($group_id, $id_only = false)
    {
        $table_user = Database :: get_main_table(TABLE_MAIN_USER);
        $table_group_tutor = Database :: get_course_table(TABLE_GROUP_TUTOR);
        $order_clause = api_sort_by_first_name(
        ) ? ' ORDER BY u.firstname, u.lastname' : ' ORDER BY u.lastname, u.firstname';
        $group_id = Database::escape_string($group_id);
        $course_id = api_get_course_int_id();

        $sql = "SELECT tg.id, u.user_id, u.lastname, u.firstname, u.email
			FROM ".$table_user." u, ".$table_group_tutor." tg
			WHERE 	tg.c_id = $course_id AND
					tg.group_id='".$group_id."' AND
					tg.user_id=u.user_id".$order_clause;
        $db_result = Database::query($sql);
        $users = array();
        while ($user = Database::fetch_object($db_result)) {
            if (!$id_only) {
                $member['user_id'] = $user->user_id;
                $member['firstname'] = $user->firstname;
                $member['lastname'] = $user->lastname;
                $member['email'] = $user->email;
                $users[] = $member;
            } else {
                $users[] = $user->user_id;
            }
        }

        return $users;
    }

    /**
     * Subscribe user(s) to a specified group in current course
     * @param mixed $user_ids Can be an array with user-id's or a single user-id
     * @param int $group_id
     * @return bool TRUE if successfull
     */
    public static function subscribe_users($user_ids, $group_id)
    {
        $user_ids = is_array($user_ids) ? $user_ids : array($user_ids);
        $result = true;
        $course_id = api_get_course_int_id();
        $table_group_user = Database :: get_course_table(TABLE_GROUP_USER);
        if (!empty($user_ids)) {
            foreach ($user_ids as $user_id) {
                $user_id = Database::escape_string($user_id);
                $group_id = Database::escape_string($group_id);
                $sql = "INSERT INTO ".$table_group_user." (c_id, user_id, group_id) VALUES ('$course_id', '".$user_id."', '".$group_id."')";
                $result &= Database::query($sql);
            }
        }

        return $result;
    }

    /**
     * Subscribe tutor(s) to a specified group in current course
     * @param mixed $user_ids Can be an array with user-id's or a single user-id
     * @param int $group_id
     * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
     * @see subscribe_users. This function is almost an exact copy of that function.
     * @return bool TRUE if successfull
     */
    public static function subscribe_tutors($user_ids, $group_id)
    {
        $user_ids = is_array($user_ids) ? $user_ids : array($user_ids);
        $result = true;
        $course_id = api_get_course_int_id();
        $table_group_tutor = Database :: get_course_table(TABLE_GROUP_TUTOR);

        foreach ($user_ids as $index => $user_id) {
            $user_id = Database::escape_string($user_id);
            $group_id = Database::escape_string($group_id);
            $sql = "INSERT INTO ".$table_group_tutor." (c_id, user_id, group_id) VALUES ('$course_id', '".$user_id."', '".$group_id."')";
            $result &= Database::query($sql);
        }

        return $result;
    }

    /**
     * Unsubscribe user(s) from a specified group in current course
     * @param mixed $user_ids Can be an array with user-id's or a single user-id
     * @param int $group_id
     * @return bool TRUE if successfull
     */
    public static function unsubscribe_users($user_ids, $group_id)
    {
        $user_ids = is_array($user_ids) ? $user_ids : array($user_ids);
        $table_group_user = Database :: get_course_table(TABLE_GROUP_USER);
        $group_id = Database::escape_string($group_id);
        $course_id = api_get_course_int_id();

        $result &= Database::query(
            'DELETE FROM '.$table_group_user.' WHERE c_id = '.$course_id.' AND group_id = '.$group_id.' AND user_id IN ('.implode(
                ',',
                $user_ids
            ).')'
        );
    }

    /**
     * Unsubscribe all users from one or more groups
     * @param mixed $group_id Can be an array with group-id's or a single group-id
     * @return bool TRUE if successfull
     */
    public static function unsubscribe_all_users($group_ids)
    {
        $course_id = api_get_course_int_id();

        $group_ids = is_array($group_ids) ? $group_ids : array($group_ids);
        $group_ids = array_map('intval', $group_ids);
        if (count($group_ids) > 0) {
            if (api_is_course_coach()) {
                for ($i = 0; $i < count($group_ids); $i++) {
                    if (!api_is_element_in_the_session(TOOL_GROUP, $group_ids[$i])) {
                        array_splice($group_ids, $i, 1);
                        $i--;
                    }
                }
                if (count($group_ids) == 0) {
                    return false;
                }
            }
            $table_group_user = Database :: get_course_table(TABLE_GROUP_USER);
            $sql = 'DELETE FROM '.$table_group_user.' WHERE group_id IN ('.implode(
                ',',
                $group_ids
            ).') AND c_id = '.$course_id;
            $result = Database::query($sql);

            return $result;
        }

        return true;
    }

    /**
     * Unsubscribe all tutors from one or more groups
     * @param mixed $group_id Can be an array with group-id's or a single group-id
     * @see unsubscribe_all_users. This function is almost an exact copy of that function.
     * @return bool TRUE if successfull
     * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
     */
    public static function unsubscribe_all_tutors($group_ids)
    {
        $course_id = api_get_course_int_id();
        $group_ids = is_array($group_ids) ? $group_ids : array($group_ids);
        if (count($group_ids) > 0) {
            $table_group_tutor = Database :: get_course_table(TABLE_GROUP_TUTOR);
            $sql = 'DELETE FROM '.$table_group_tutor.' WHERE group_id IN ('.implode(
                ',',
                $group_ids
            ).') AND c_id = '.$course_id;
            $result = Database::query($sql);

            return $result;
        }

        return true;
    }

    /**
     * Is the user a tutor of this group?
     * @param $user_id the id of the user
     * @param $group_id the id of the group
     * @return boolean true/false
     * @todo use the function user_has_access that includes this function
     * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
     */
    public static function is_tutor_of_group($user_id, $group_id)
    {
        $_course = api_get_course_info();

        $table_group_tutor = Database :: get_course_table(TABLE_GROUP_TUTOR);
        $user_id = Database::escape_string($user_id);
        $group_id = Database::escape_string($group_id);
        $course_id = api_get_course_int_id();

        $sql = "SELECT * FROM ".$table_group_tutor." WHERE c_id = $course_id AND user_id='".$user_id."' AND group_id='".$group_id."'";
        $result = Database::query($sql);
        if (Database::num_rows($result) > 0) {
            return true;
        } else {
            return false;
        }
    }

    /**
     * Is the user part of this group? This can be a tutor or a normal member
     * you should use this function if the access to a tool or functionality is restricted to the people who are actually in the group
     * before you had to check if the user was 1. a member of the group OR 2. a tutor of the group. This function combines both
     * @param $user_id the id of the user
     * @param $group_id the id of the group
     * @return boolean true/false
     * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
     */
    public static function is_user_in_group($user_id, $group_id)
    {
        $member = self :: is_subscribed($user_id, $group_id);
        $tutor = self :: is_tutor_of_group($user_id, $group_id);
        if ($member OR $tutor) {
            return true;
        } else {
            return false;
        }
    }

    /**
     * Get all tutors for the current course.
     * @return array An array with firstname, lastname and user_id for all
     *               tutors in the current course.
     * @deprecated this function uses the old tutor implementation
     */
    public static function get_all_tutors()
    {
        $course_user_table = Database :: get_main_table(TABLE_MAIN_COURSE_USER);
        $user_table = Database :: get_main_table(TABLE_MAIN_USER);
        $sql = "SELECT user.user_id AS user_id, user.lastname AS lastname, user.firstname AS firstname
				FROM ".$user_table." user, ".$course_user_table." cu
				WHERE cu.user_id=user.user_id
				AND cu.tutor_id='1'
				AND cu.c_id='".api_get_course_int_id()."'";
        $resultTutor = Database::query($sql);
        $tutors = array();
        while ($tutor = Database::fetch_array($resultTutor)) {
            $tutors[] = $tutor;
        }

        return $tutors;
    }


    /**
     * Is user a tutor in current course
     * @param int $user_id
     * @return bool TRUE if given user is a tutor in the current course.
     * @deprecated this function uses the old tutor implementation
     */
    public static function is_tutor($user_id)
    {
        $course_user_table = Database::get_main_table(TABLE_MAIN_COURSE_USER);
        $user_id = Database::escape_string($user_id);

        $sql = "SELECT tutor_id FROM ".$course_user_table."
		        WHERE user_id = '".$user_id."' AND c_id ='".api_get_course_int_id()."'"."AND tutor_id=1";
        $db_result = Database::query($sql);
        $result = (Database::num_rows($db_result) > 0);

        return $result;
    }

    /**
     * Get all group's from a given course in which a given user is unsubscribed
     * @author  Patrick Cool
     * @param     int  course id
     * retrieve the groups for
     * @param integer $user_id: the ID of the user you want to know all its
     * group memberships
     */
    public static function get_group_ids($course_id, $user_id)
    {
        $groups = array();
        $tbl_group = Database::get_course_table(TABLE_GROUP_USER);
        $tbl_group_tutor = Database::get_course_table(TABLE_GROUP_TUTOR);
        $user_id = intval($user_id);
        $course_id = intval($course_id);

        $sql = "SELECT group_id FROM $tbl_group WHERE c_id = $course_id AND user_id = '$user_id'";
        $groupres = Database::query($sql);

        if ($groupres) {
            while ($myrow = Database::fetch_array($groupres)) {
                $groups[] = $myrow['group_id'];
            }
        }

        //Also loading if i'm the tutor
        $sql = "SELECT group_id FROM $tbl_group_tutor WHERE c_id = $course_id AND user_id = '$user_id'";
        $groupres = Database::query($sql);
        if ($groupres) {
            while ($myrow = Database::fetch_array($groupres)) {
                $groups[] = $myrow['group_id'];
            }
        }
        if (!empty($groups)) {
            array_filter($groups);
        }

        return $groups;
    }

    /*
        Group functions - these take virtual/linked courses into account when necessary
    */

    /**
     *    Filter out duplicates in a multidimensional array
     *    by comparing field $compare_field.
     *
     * @param $user_array_in list of users (must be sorted).
     * @param string $compare_field, the field to be compared
     */
    public static function filter_duplicates($user_array_in, $compare_field)
    {
        $total_number = count($user_array_in);
        $user_array_out[0] = $user_array_in[0];
        $count_out = 0;
        for ($count_in = 1; $count_in < $total_number; $count_in++) {
            if ($user_array_in[$count_in][$compare_field] != $user_array_out[$count_out][$compare_field]) {
                $count_out++;
                $user_array_out[$count_out] = $user_array_in[$count_in];
            }
        }

        return $user_array_out;
    }

    /**
     *    Filters from the array $user_array_in the users already in the group $group_id.
     */
    public static function filter_users_already_in_group($user_array_in, $group_id)
    {
        foreach ($user_array_in as $this_user) {
            if (!self :: is_subscribed($this_user['user_id'], $group_id)) {
                $user_array_out[] = $this_user;
            }
        }

        return $user_array_out;
    }

    /**
     * Remove all users that are not students and all users who have tutor status
     * from  the list.
     */
    public static function filter_only_students($user_array_in)
    {
        $user_array_out = array();
        foreach ($user_array_in as $this_user) {
            //if ($this_user['status_rel'] == STUDENT && $this_user['tutor_id'] == 0) {
            if (api_get_session_id()) {
                if ($this_user['status_session'] == 0) {
                    $user_array_out[] = $this_user;
                }
            } else {
                if ($this_user['status_rel'] == STUDENT) {
                    $user_array_out[] = $this_user;
                }
            }
        }

        return $user_array_out;
    }

    /**
     * Check if a user has access to a certain group tool
     * @param int $user_id The user id
     * @param int $group_id The group id
     * @param constant $tool The tool to check the access rights. This should be
     * one of constants: GROUP_TOOL_DOCUMENTS
     * @return bool True if the given user has access to the given tool in the
     * given course.
     */
    public static function user_has_access($user_id, $group_id, $tool)
    {

        //Admin have access everywhere
        if (api_is_platform_admin()) {
            return true;
        }
        //Course admin also have access to everything
        if (api_is_allowed_to_edit()) {
            return true;
        }

        switch ($tool) {
            case self::GROUP_TOOL_FORUM :
                $state_key = 'forum_state';
                break;
            case self::GROUP_TOOL_DOCUMENTS :
                $state_key = 'doc_state';
                break;
            case self::GROUP_TOOL_CALENDAR :
                $state_key = 'calendar_state';
                break;
            case self::GROUP_TOOL_ANNOUNCEMENT :
                $state_key = 'announcements_state';
                break;
            case self::GROUP_TOOL_WORK :
                $state_key = 'work_state';
                break;
            case self::GROUP_TOOL_WIKI :
                $state_key = 'wiki_state';
                break;
            case self::GROUP_TOOL_CHAT :
                $state_key = 'chat_state';
                break;
            default:
                return false;
        }

        $user_is_in_group = self :: is_user_in_group($user_id, $group_id);

        //Check group properties
        $group_info = self :: get_group_properties($group_id);

        if (api_get_setting('allow_group_categories') == 'true') {
            //Check group category if exists
            $category_group_info = self::get_category_from_group($group_id);

            if (!empty($category_group_info)) {
                //if exists check the category group status first
                if ($category_group_info[$state_key] == self::TOOL_NOT_AVAILABLE) {
                    return false;
                } elseif ($category_group_info[$state_key] == self::TOOL_PRIVATE && !$user_is_in_group) {
                    return false;
                }
            }
        }

        //is_user_in_group() is more complete that  the  is_subscribed() function

        if ($group_info[$state_key] == self::TOOL_NOT_AVAILABLE) {
            return false;
        } elseif ($group_info[$state_key] == self::TOOL_PUBLIC) {
            return true;
        } elseif (api_is_allowed_to_edit(false, true)) {
            return true;
        } elseif ($group_info['tutor_id'] == $user_id) { //this tutor implementation was dropped
            return true;
        } elseif ($group_info[$state_key] == self::TOOL_PRIVATE && !$user_is_in_group) {
            return false;
        } else {
            return $user_is_in_group;
        }
    }

    /**
     * Get all groups where a specific user is subscribed
     */
    public static function get_user_group_name($user_id)
    {
        $table_group_user = Database::get_course_table(TABLE_GROUP_USER);
        $table_group = Database::get_course_table(TABLE_GROUP);
        $user_id = intval($user_id);
        $course_id = api_get_course_int_id();
        $sql_groups = "SELECT name FROM $table_group g  INNER JOIN $table_group_user gu
                       ON (gu.group_id=g.id)
		               WHERE    gu.c_id= $course_id AND
                                g.c_id= $course_id AND
                                gu.user_id = $user_id";
        $res = Database::query($sql_groups);
        $groups = array();
        while ($group = Database::fetch_array($res)) {
            $groups[] .= $group['name'];
        }

        return $groups;
    }

    /**
     *   fill_groups_list
     *
     * see : fill_groups
     *       Fill the groups with students.
     *
     * note :
     *        optimize fill_groups_list <--> fill_groups
     *
     */
    public static function fill_groups_list($group_ids)
    {
        $group_ids = is_array($group_ids) ? $group_ids : array($group_ids);
        $group_ids = array_map('intval', $group_ids);
        if (api_is_course_coach()) {
            for ($i = 0; $i < count($group_ids); $i++) {
                if (!api_is_element_in_the_session(TOOL_GROUP, $group_ids[$i])) {
                    array_splice($group_ids, $i, 1);
                    $i--;
                }
            }
            if (count($group_ids) == 0) {
                return false;
            }
        }

        $_course = api_get_course_info();
        $category = self :: get_category_from_group($group_ids[0]);
        $groups_per_user = $category['groups_per_user'];

        $group_table = Database :: get_course_table(TABLE_GROUP);
        $group_user_table = Database :: get_course_table(TABLE_GROUP_USER);
        $session_id = api_get_session_id();
        $complete_user_list = CourseManager :: get_real_and_linked_user_list($_course['sysCode'], true, $session_id);
        $number_groups_per_user = ($groups_per_user == self::GROUP_PER_MEMBER_NO_LIMIT ? self::INFINITE : $groups_per_user);
        $course_id = api_get_course_int_id();
        /*
         * Retrieve all the groups where enrollment is still allowed
         * (reverse) ordered by the number of place available
         */
        $sql = "SELECT g.id gid, g.max_student - count(ug.user_id) nbPlaces, g.max_student
                FROM ".$group_table." g
                LEFT JOIN  ".$group_user_table." ug
                ON    g.id = ug.group_id
                WHERE   g.c_id = $course_id AND
                        ug.c_id = $course_id AND
                        g.id IN (".implode(',', $group_ids).")
                GROUP BY (g.id)
                HAVING (nbPlaces > 0 OR g.max_student = ".self::MEMBER_PER_GROUP_NO_LIMIT.")
                ORDER BY nbPlaces DESC";
        $sql_result = Database::query($sql);
        $group_available_place = array();
        while ($group = Database::fetch_array($sql_result, 'ASSOC')) {
            $group_available_place[$group['gid']] = $group['nbPlaces'];
        }

        /*
         * Retrieve course users (reverse) ordered by the number
         * of group they are already enrolled
         */
        for ($i = 0; $i < count($complete_user_list); $i++) {

            //find # of groups the user is enrolled in
            $number_of_groups = self :: user_in_number_of_groups($complete_user_list[$i]["user_id"], $category['id']);
            //add # of groups to user list
            $complete_user_list[$i]['number_groups_left'] = $number_groups_per_user - $number_of_groups;
        }
        //first sort by user_id to filter out duplicates
        $complete_user_list = TableSort :: sort_table($complete_user_list, 'user_id');
        $complete_user_list = self :: filter_duplicates($complete_user_list, 'user_id');

        //now sort by # of group left
        $complete_user_list = TableSort :: sort_table($complete_user_list, 'number_groups_left', SORT_DESC);

        return $complete_user_list;
    }

    static function process_groups($group_list, $category_id = null)
    {
        global $origin, $charset;
        $category_id = intval($category_id);

        $totalRegistered = 0;
        $group_data = array();
        $user_info = api_get_user_info();
        $session_id = api_get_session_id();
        $user_id = $user_info['user_id'];

        $orig = isset($origin) ? $origin : null;

        foreach ($group_list as $this_group) {

            // Validacion when belongs to a session
            $session_img = api_get_session_image($this_group['session_id'], $user_info['status']);

            // All the tutors of this group
            $tutorsids_of_group = self::get_subscribed_tutors($this_group['id'], true);

            // Create a new table-row
            $row = array();
            // Checkbox
            if (api_is_allowed_to_edit(false, true) && count($group_list) > 1) {
                $row[] = $this_group['id'];
            }

            // Group name
            if ((api_is_allowed_to_edit(false, true) ||
                in_array($user_id, $tutorsids_of_group) ||
                $this_group['is_member'] ||
                self::user_has_access($user_id, $this_group['id'], self::GROUP_TOOL_FORUM) ||
                self::user_has_access($user_id, $this_group['id'], self::GROUP_TOOL_DOCUMENTS) ||
                self::user_has_access($user_id, $this_group['id'], self::GROUP_TOOL_CALENDAR) ||
                self::user_has_access($user_id, $this_group['id'], self::GROUP_TOOL_ANNOUNCEMENT) ||
                self::user_has_access($user_id, $this_group['id'], self::GROUP_TOOL_WORK) ||
                self::user_has_access($user_id, $this_group['id'], self::GROUP_TOOL_WIKI))
                && !(api_is_course_coach() && intval($this_group['session_id']) != $session_id)
            ) {

                $group_name = '<a href="group_space.php?cidReq='.api_get_course_id(
                ).'&amp;origin='.$orig.'&amp;gidReq='.$this_group['id'].'">'.Security::remove_XSS(
                    $this_group['name']
                ).'</a> ';
                if (!empty($user_id) && !empty($this_group['id_tutor']) && $user_id == $this_group['id_tutor']) {
                    $group_name .= Display::label(get_lang('OneMyGroups'), 'success');
                } elseif ($this_group['is_member']) {
                    $group_name .= Display::label(get_lang('MyGroup'), 'success');
                }

                if (api_is_allowed_to_edit() && !empty($this_group['session_name'])) {
                    $group_name .= ' ('.$this_group['session_name'].')';
                }
                $group_name .= $session_img;
                $row[] = $group_name.'<br />'.stripslashes(trim($this_group['description']));
            } else {
                $row[] = $this_group['name'].'<br />'.stripslashes(trim($this_group['description']));
            }

            // Tutor name
            $tutor_info = null;

            if (count($tutorsids_of_group) > 0) {
                foreach ($tutorsids_of_group as $tutor_id) {
                    $tutor = api_get_user_info($tutor_id);
                    $username = api_htmlentities(sprintf(get_lang('LoginX'), $tutor['username']), ENT_QUOTES);
                    if (api_get_setting('show_email_addresses') == 'true') {
                        $tutor_info .= Display::tag(
                            'span',
                            Display::encrypted_mailto_link(
                                $tutor['mail'],
                                api_get_person_name($tutor['firstName'], $tutor['lastName'])
                            ),
                            array('title' => $username)
                        ).', ';
                    } else {
                        if (api_is_allowed_to_edit()) {
                            $tutor_info .= Display::tag(
                                'span',
                                Display::encrypted_mailto_link(
                                    $tutor['mail'],
                                    api_get_person_name($tutor['firstName'], $tutor['lastName'])
                                ),
                                array('title' => $username)
                            ).', ';
                        } else {
                            $tutor_info .= Display::tag(
                                'span',
                                api_get_person_name($tutor['firstName'], $tutor['lastName']),
                                array('title' => $username)
                            ).', ';
                        }
                    }
                }
            }
            $tutor_info = api_substr($tutor_info, 0, api_strlen($tutor_info) - 2);
            $row[] = $tutor_info;

            // Max number of members in group
            $max_members = ($this_group['maximum_number_of_members'] == self::MEMBER_PER_GROUP_NO_LIMIT ? ' ' : ' / '.$this_group['maximum_number_of_members']);

            // Number of members in group
            $row[] = $this_group['number_of_members'].$max_members;

            // Self-registration / unregistration
            if (!api_is_allowed_to_edit(false, true)) {
                if (self :: is_self_registration_allowed($user_id, $this_group['id'])) {
                    $row[] = '<a class = "btn" href="group.php?'.api_get_cidreq(
                    ).'&category='.$category_id.'&amp;action=self_reg&amp;group_id='.$this_group['id'].'" onclick="javascript:if(!confirm('."'".addslashes(
                        api_htmlentities(get_lang('ConfirmYourChoice'), ENT_QUOTES, $charset)
                    )."'".')) return false;">'.get_lang('GroupSelfRegInf').'</a>';
                } elseif (self :: is_self_unregistration_allowed($user_id, $this_group['id'])) {
                    $row[] = '<a class = "btn" href="group.php?'.api_get_cidreq(
                    ).'&category='.$category_id.'&amp;action=self_unreg&amp;group_id='.$this_group['id'].'" onclick="javascript:if(!confirm('."'".addslashes(
                        api_htmlentities(get_lang('ConfirmYourChoice'), ENT_QUOTES, $charset)
                    )."'".')) return false;">'.get_lang('GroupSelfUnRegInf').'</a>';
                } else {
                    $row[] = '-';
                }
            }

            // Edit-links
            if (api_is_allowed_to_edit(false, true) && !(api_is_course_coach() && intval(
                $this_group['session_id']
            ) != $session_id)
            ) {
                $edit_actions = '<a href="group_edit.php?'.api_get_cidreq(
                    true,
                    false
                ).'&gidReq='.$this_group['id'].'"  title="'.get_lang('Edit').'">'.Display::return_icon(
                    'edit.png',
                    get_lang('EditGroup'),
                    '',
                    ICON_SIZE_SMALL
                ).'</a>&nbsp;';
                $edit_actions .= '<a href="'.api_get_self().'?'.api_get_cidreq(
                    true,
                    false
                ).'&category='.$category_id.'&amp;action=empty_one&amp;id='.$this_group['id'].'" onclick="javascript: if(!confirm('."'".addslashes(
                    api_htmlentities(get_lang('ConfirmYourChoice'), ENT_QUOTES)
                )."'".')) return false;" title="'.get_lang('EmptyGroup').'">'.
                    Display::return_icon('clean.png', get_lang('EmptyGroup'), '', ICON_SIZE_SMALL).'</a>&nbsp;';
                $edit_actions .= '<a href="'.api_get_self().'?'.api_get_cidreq(
                    true,
                    false
                ).'&category='.$category_id.'&amp;action=fill_one&amp;id='.$this_group['id'].'" onclick="javascript: if(!confirm('."'".addslashes(
                    api_htmlentities(get_lang('ConfirmYourChoice'), ENT_QUOTES)
                )."'".')) return false;" title="'.get_lang('FillGroup').'">'.
                    Display::return_icon('fill.png', get_lang('FillGroup'), '', ICON_SIZE_SMALL).'</a>&nbsp;';
                $edit_actions .= '<a href="'.api_get_self().'?'.api_get_cidreq(
                    true,
                    false
                ).'&category='.$category_id.'&amp;action=delete_one&amp;id='.$this_group['id'].'" onclick="javascript: if(!confirm('."'".addslashes(
                    api_htmlentities(get_lang('ConfirmYourChoice'), ENT_QUOTES)
                )."'".')) return false;" title="'.get_lang('Delete').'">'.
                    Display::return_icon('delete.png', get_lang('Delete'), '', ICON_SIZE_SMALL).'</a>&nbsp;';
                $row[] = $edit_actions;
            }
            if (!empty($this_group['nbMember'])) {
                $totalRegistered = $totalRegistered + $this_group['nbMember'];
            }
            $group_data[] = $row;
        } // end loop

        if (isset($_GET['show_all'])) {
            $paging_options = array('per_page' => count($group_data));
        } else {
            $paging_options = array();
        }

        $table = new SortableTableFromArrayConfig($group_data, 1, 20, 'group_category_'.$category_id);
        //$my_cat = isset($_GET['category']) ? Security::remove_XSS($_GET['category']) : null;
        $table->set_additional_parameters(array('category' => $category_id));
        $column = 0;
        if (api_is_allowed_to_edit(false, true) and count($group_list) > 1) {
            $table->set_header($column++, '', false);
        }
        $table->set_header($column++, get_lang('Groups'));
        $table->set_header($column++, get_lang('GroupTutor'));
        $table->set_header($column++, get_lang('Registered'), false);

        if (!api_is_allowed_to_edit(false, true)) { // If self-registration allowed
            $table->set_header($column++, get_lang('GroupSelfRegistration'), false);
        }
        if (api_is_allowed_to_edit(false, true)) { // Only for course administrator
            $table->set_header($column++, get_lang('Modify'), false);
            $form_actions = array();
            $form_actions['fill_selected'] = get_lang('FillGroup');
            $form_actions['empty_selected'] = get_lang('EmptyGroup');
            $form_actions['delete_selected'] = get_lang('Delete');
            if (count($group_list) > 1) {
                $table->set_form_actions($form_actions, 'group');
            }
        }
        $table->display();
    }
}