<?php
/**
 * DokuWiki Plugin struct (Helper Component)
 */

// must be run within Dokuwiki
if(!defined('DOKU_INC')) die();

class helper_plugin_structgroup_authgroup extends DokuWiki_Plugin {
    protected $groupsloaded = false;
    protected $groups = array();

    protected function loadGroupsFromAcl() {
        global $AUTH_ACL;
        if (!isset($AUTH_ACL) || !is_array($AUTH_ACL)) return array();

        $specials = array('ALL');
        $groups = [];
        foreach($AUTH_ACL as $line){
            $line = trim(preg_replace('/#.*$/','',$line)); //ignore comments
            if(!$line) continue;

            $acl = preg_split('/[ \t]+/',$line);
            //0 is pagename, 1 is user, 2 is acl

            $grp = rawurldecode($acl[1]);
            //it's not a group
            if ($grp[0] != '@') continue;
            $grp = substr($grp, 1);
            if(in_array($grp,$specials)) continue;
            $groups[] = $grp;
        }

        return array_unique($groups);
    }

    protected function loadGroups() {
        /** @var \DokuWiki_Auth_Plugin $auth */
        global $auth;

        if(!$auth->canDo('getUsers')) {
            msg('The user backend can not search for users', -1);
            return false;
        }

        $groups = array_map(function($userinfo) { return $userinfo['grps']; }, $auth->retrieveUsers());
        $groups = call_user_func_array('array_merge', $groups);
        $groups = array_merge($groups, $this->loadGroupsFromAcl());

        $this->groups = array_unique($groups);
        $this->groupsloaded = true;
    }

    public function getGroups($length = NULL, $filter = '') {
        if (!$this->groupsloaded) {
            $this->loadGroups();
        }

        $groups = $this->groups;
        if ($filter != '') $groups = array_filter($groups, function ($group) use ($filter) {
            return strpos($group, $filter) === 0;
        });

        return array_slice($groups, 0, $length);
    }

}