<?php //$Id$

/**
 * This block needs to be reworked.
 * The new roles system does away with the concepts of rigid student and
 * teacher roles.
 */
class block_online_users extends block_base {
    function init() {
        $this->title = get_string('blockname','block_online_users');
        $this->version = 2007101509;
    }

    function has_config() {return true;}

    function get_content() {
        global $USER, $CFG, $COURSE, $DB;

        if ($this->content !== NULL) {
            return $this->content;
        }

        $this->content = new stdClass;
        $this->content->text = '';
        $this->content->footer = '';
        
        if (empty($this->instance)) {
            return $this->content;
        }

        $timetoshowusers = 300; //Seconds default
        if (isset($CFG->block_online_users_timetosee)) {
            $timetoshowusers = $CFG->block_online_users_timetosee * 60;
        }
        $timefrom = 100 * floor((time()-$timetoshowusers) / 100); // Round to nearest 100 seconds for better query cache

        // Get context so we can check capabilities.
        $context = get_context_instance(CONTEXT_COURSE, $COURSE->id);

        //Calculate if we are in separate groups
        $isseparategroups = ($COURSE->groupmode == SEPARATEGROUPS 
                             && $COURSE->groupmodeforce
                             && !has_capability('moodle/site:accessallgroups', $context));

        //Get the user current group
        $currentgroup = $isseparategroups ? groups_get_course_group($COURSE) : NULL;

        $groupmembers = "";
        $groupselect = "";
        $params = array();

        //Add this to the SQL to show only group users
        if ($currentgroup !== NULL) {
            $groupmembers = ", {groups_members} gm";
            $groupselect = "AND u.id = gm.userid AND gm.groupid = :currentgroup";
            $params['currentgroup'] = $currentgroup;
        }

        if ($COURSE->id == SITEID) {  // Site-level
            $sql = "SELECT u.id, u.username, u.firstname, u.lastname, u.picture, MAX(u.lastaccess) AS lastaccess
                      FROM {user} u $groupmembers
                     WHERE u.lastaccess > $timefrom
                           $groupselect
                  GROUP BY u.id, u.username, u.firstname, u.lastname, u.picture
                  ORDER BY lastaccess DESC ";
            
        } else { // Course-level
            $sql = "SELECT u.id, u.username, u.firstname, u.lastname, u.picture, MAX(ul.timeaccess) AS lastaccess
                      FROM {user_lastaccess} ul, {user} u $groupmembers
                     WHERE ul.timeaccess > $timefrom
                           AND u.id = ul.userid
                           AND ul.courseid = :courseid
                           $groupselect
                  GROUP BY u.id, u.username, u.firstname, u.lastname, u.picture
                  ORDER BY lastaccess DESC";
            $params['courseid'] = $COURSE->id;
        }
        
        $users = array();        
        $pcontext = get_related_contexts_string($context);
    
        if ($pusers = $DB->get_records_sql($sql, $params, 0, 50)) {   // We'll just take the most recent 50 maximum
            $hidden = false;

            if (!has_capability('moodle/role:viewhiddenassigns', $context)) {
                // if current user can't view hidden role assignment in this context and 
                // user has a hidden role assigned at this context or any parent contexts,
                // ignore this user
                $userids = array_keys($pusers);
                $userids = implode(',', $userids);
                $sql = "SELECT userid
                          FROM {role_assignments}
                         WHERE userid IN ($userids) AND contextid $pcontext AND hidden = 1
                      GROUP BY userid";
                $hidden = $DB->get_records_sql($sql);
            }

            foreach ($pusers as $puser) {
                if ($hidden and isset($hidden[$puser->id])) {
                    continue;
                }

                $puser->fullname = fullname($puser);
                $users[$puser->id] = $puser;  
            }
        }  
           
        //Calculate minutes
        $minutes  = floor($timetoshowusers/60);

        $this->content->text = "<div class=\"info\">(".get_string("periodnminutes","block_online_users",$minutes).")</div>";

        //Now, we have in users, the list of users to show
        //Because they are online
        if (!empty($users)) {
            //Accessibility: Don't want 'Alt' text for the user picture; DO want it for the envelope/message link (existing lang string).
            //Accessibility: Converted <div> to <ul>, inherit existing classes & styles.
            $this->content->text .= "<ul class='list'>\n";
            foreach ($users as $user) {
                $this->content->text .= '<li class="listentry">';
                $timeago = format_time(time() - $user->lastaccess); //bruno to calculate correctly on frontpage 
                if ($user->username == 'guest') {
                    $this->content->text .= '<div class="user">'.print_user_picture($user->id, $COURSE->id, $user->picture, 16, true, false, '', false);
                    $this->content->text .= get_string('guestuser').'</div>';

                } else {
                    $this->content->text .= '<div class="user"><a href="'.$CFG->wwwroot.'/user/view.php?id='.$user->id.'&amp;course='.$COURSE->id.'" title="'.$timeago.'">';
                    $this->content->text .= print_user_picture($user->id, $COURSE->id, $user->picture, 16, true, false, '', false);
                    $this->content->text .= $user->fullname.'</a></div>';
                }
                if (!empty($USER->id) and ($USER->id != $user->id) and !empty($CFG->messaging) and 
                    !isguest() and $user->username != 'guest') {  // Only when logged in and messaging active etc
                    $this->content->text .= '<div class="message"><a title="'.get_string('messageselectadd').'" href="'.$CFG->wwwroot.'/message/discussion.php?id='.$user->id.'" onclick="this.target=\'message_'.$user->id.'\';return openpopup(\'/message/discussion.php?id='.$user->id.'\', \'message_'.$user->id.'\', \'menubar=0,location=0,scrollbars,status,resizable,width=400,height=500\', 0);">'
                        .'<img class="iconsmall" src="'.$CFG->pixpath.'/t/message.gif" alt="'. get_string('messageselectadd') .'" /></a></div>';
                }
                $this->content->text .= "</li>\n";
            }
            $this->content->text .= '</ul><div class="clearer"><!-- --></div>';
        } else {
            $this->content->text .= "<div class=\"info\">".get_string("none")."</div>";
        }

        return $this->content;
    }
}

?>