/**
 * Removes all grades from gradebook
 * @param int $courseid
 * @param string optional type
 */
function forum_reset_gradebook($courseid, $type = '')
{
    global $CFG;
    $type = $type ? "AND f.type='{$type}'" : '';
    $sql = "SELECT f.*, cm.idnumber as cmidnumber, f.course as courseid\n              FROM {$CFG->prefix}forum f, {$CFG->prefix}course_modules cm, {$CFG->prefix}modules m\n             WHERE m.name='forum' AND m.id=cm.module AND cm.instance=f.id AND f.course={$courseid} {$type}";
    if ($forums = get_records_sql($sql)) {
        foreach ($forums as $forum) {
            forum_grade_item_update($forum, 'reset');
        }
    }
}

/**
 * Removes all grades from gradebook
 *
 * @global object
 * @global object
 * @param int $courseid
 * @param string $type optional
 */
function forum_reset_gradebook($courseid, $type='') {
    global $CFG, $DB;

    $wheresql = '';
    $params = array($courseid);
    if ($type) {
        $wheresql = "AND f.type=?";
        $params[] = $type;
    }

    $sql = "SELECT f.*, cm.idnumber as cmidnumber, f.course as courseid
              FROM {forum} f, {course_modules} cm, {modules} m
             WHERE m.name='forum' AND m.id=cm.module AND cm.instance=f.id AND f.course=? $wheresql";

    if ($forums = $DB->get_records_sql($sql, $params)) {
        foreach ($forums as $forum) {
            forum_grade_item_update($forum, 'reset');
        }
    }
}

/**
 * Update grades by firing grade_updated event
 *
 * @param object $forum null means all forums
 * @param int $userid specific user only, 0 mean all
 */
function forum_update_grades($forum = null, $userid = 0, $nullifnone = true)
{
    global $CFG;
    if ($forum != null) {
        require_once $CFG->libdir . '/gradelib.php';
        if ($grades = forum_get_user_grades($forum, $userid)) {
            grade_update('mod/forum', $forum->course, 'mod', 'forum', $forum->id, 0, $grades);
        } else {
            if ($userid and $nullifnone) {
                $grade = new object();
                $grade->userid = $userid;
                $grade->rawgrade = NULL;
                grade_update('mod/forum', $data->course, 'mod', 'forum', $forum->id, 0, $grade);
            }
        }
    } else {
        $sql = "SELECT f.*, cm.idnumber as cmidnumber\n                  FROM {$CFG->prefix}forum f, {$CFG->prefix}course_modules cm, {$CFG->prefix}modules m\n                 WHERE m.name='forum' AND m.id=cm.module AND cm.instance=f.id";
        if ($rs = get_recordset_sql($sql)) {
            if ($rs->RecordCount() > 0) {
                while ($forum = rs_fetch_next_record($rs)) {
                    forum_grade_item_update($forum);
                    if ($forum->assessed) {
                        forum_update_grades($forum, 0, false);
                    }
                }
            }
            rs_close($rs);
        }
    }
}