<?php

    /**
     * Returns list of users enrolled into course.
     *
     * @package   core_enrol
     * @category  access
     *
     * @param context $context
     * @param string $withcapability
     * @param int $groupid 0 means ignore groups, any other value limits the result by group id
     * @param string $userfields requested user record fields
     * @param string $orderby
     * @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
     * @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
     * @param bool $onlyactive consider only active enrolments in enabled plugins and time restrictions
     * @param object $cm the course module record
     * @return array of user records
     */
    function get_enrolled_users(context $context, $withcapability = '', $groupid = 0, $userfields = 'u.*', $orderby = null,
            $limitfrom = 0, $limitnum = 0, $onlyactive = false, $cm=null) {
        global $CFG, $DB;

        $membershipsql = '';
        
        if (! is_null($cm)) {
            if ((! empty($CFG->enablegroupmembersonly)) AND (! empty($cm->groupmembersonly))) {
                if ($cm->groupingid) {
                    $membershipsql .= ' JOIN (SELECT DISTINCT usr.id ';
                    $membershipsql .= '         FROM {user}             usr ';
                    $membershipsql .= '            , {groups_members}   grm ';
                    $membershipsql .= '            , {groupings_groups} grg ';
                    $membershipsql .= '        WHERE usr.id         = grm.userid ';
                    $membershipsql .= '          AND grm.groupid    = grg.groupid ';
                    $membershipsql .= '          AND grg.groupingid = '.$cm->groupingid.') gpm ';
                    $membershipsql .= '   ON gpm.id = u.id  ';
                } else {
                    $membershipsql .= ' JOIN (SELECT DISTINCT usr.id ';
                    $membershipsql .= '         FROM {user}           usr ';
                    $membershipsql .= '            , {groups_members} grm ';
                    $membershipsql .= '            , {groups}         grp ';
                    $membershipsql .= '        WHERE usr.id       = grm.userid ';
                    $membershipsql .= '          AND grm.groupid  = grp.id ';
                    $membershipsql .= '          AND grp.courseid = '.$cm->course.') gpm ';
                    $membershipsql .= '   ON gpm.id = u.id  ';
                }
            }
        }

        list($esql, $params) = get_enrolled_sql($context, $withcapability, $groupid, $onlyactive);
        $sql = "SELECT $userfields
                  FROM {user} u
                  JOIN ($esql) je ON je.id = u.id
                  $membershipsql
                 WHERE u.deleted = 0";

        if ($orderby) {
            $sql = "$sql ORDER BY $orderby";
        } else {
            list($sort, $sortparams) = users_order_by_sql('u');
            $sql = "$sql ORDER BY $sort";
            $params = array_merge($params, $sortparams);
        }

        return $DB->get_records_sql($sql, $params, $limitfrom, $limitnum);
    }