<?php

define('LOGIN_USED', 'Přihlašovací jméno již použito.');
define('NAME_USED', 'Jméno uživatele již použito');
define('EMAIL_USED', 'Email je již použitý. Použijte jiný email nebo si můžete nechat zaslat nové heslo na email.');
define('USER_REGISTRATED', 'Uživatel registrován. Na zadanou emailovou adresu byl poslán mail s odkazem pro aktivování účtu.');
define('USER_NOT_HUMAN', 'Uživate nepotvrdil, že je člověk.');
define('USER_REGISTRATION_CONFIRMED', 'Vaše registrace byla potvrzena.');
define('DATA_MISSING', 'Chybí emailová adresa, přezdívka, nebo některé z hesel.');
define('PASSWORDS_UNMATCHED', 'Hesla si neodpovídají.');
define('ACCOUNT_LOCKED', 'Účet je uzamčen. Po registraci je nutné provést aktivaci účtu pomocí odkazu zaslaného v aktivačním emailu.');
define('USER_NOT_LOGGED', 'Nejste přihlášen.');
define('USER_LOGGED', 'Uživatel přihlášen.');
define('USER_NOT_REGISTRED', 'Uživatel neregistrován.');
define('USER_ALREADY_LOGGED', 'Uživatel již přihlášen.');
define('USER_LOGGED_IN', 'Byl jste přihlášen.');
define('USER_LOGGED_OUT', 'Byl jste odhlášen.');
define('BAD_PASSWORD', 'Špatné heslo.');
define('USER_NOT_FOUND', 'Uživatel nenalezen.');
define('USER_PASSWORD_RECOVERY_SUCCESS', 'Přihlašovací údaje byly odeslány na zadanou emailovou adresu.');
define('USER_PASSWORD_RECOVERY_FAIL', 'Podle zadaných údajů nebyl nalezen žádný uživatel.');
define('USER_PASSWORD_RECOVERY_CONFIRMED', 'Nové heslo bylo aktivováno.');

define('USER_EVENT_REGISTER', 1);
define('USER_EVENT_LOGIN', 2);
define('USER_EVENT_LOGOUT', 3);
define('USER_EVENT_OPTIONS_CHANGED', 4);

class PasswordHash
{
  function Hash(string $Password, string $Salt): string
  {
    return sha1(sha1($Password).$Salt);
  }

  function Verify(string $Password, string $Salt, string $StoredHash): bool
  {
    return $this->Hash($Password, $Salt) == $StoredHash;
  }

  function GetSalt(): string
  {
    mt_srand(intval(microtime(true)) * 100000 + memory_get_usage(true));
    return sha1(uniqid(mt_rand(), true));
  }
}

// TODO: Make User class more general without dependencies on System, Mail, Log

class User extends Model
{
  public array $Roles = array();
  public array $User = array();
  public int $OnlineStateTimeout;
  public array $PermissionCache = array();
  public array $PermissionGroupCache = array();
  public array $PermissionGroupCacheOp = array();
  public PasswordHash $PasswordHash;

  function __construct(System $System)
  {
    parent::__construct($System);
    $this->OnlineStateTimeout = 600; // in seconds
    $this->PasswordHash = new PasswordHash();
    $this->User = array('Id' => null);
  }

  static function GetModelDesc(): ModelDesc
  {
    $Desc = new ModelDesc(self::GetClassName());
    $Column = $Desc->AddString('Login');
    $Column->Unique = true;
    $Column = $Desc->AddString('Name');
    $Column->Unique = true;
    $Desc->AddString('Password');
    $Desc->AddString('Salt');
    $Desc->AddString('Email');
    $Column = $Desc->AddString('LastIpAddress');
    $Column->HasDefault = true;
    $Column->Nullable = true;
    $Column = $Desc->AddDateTime('LastLoginTime');
    $Column->Nullable = true;
    $Column->HasDefault = true;
    $Desc->AddDateTime('RegistrationTime');
    $Desc->AddBoolean('Locked');
    $Column = $Desc->AddString('InitPassword');
    $Column->Nullable = true;
    $Column->HasDefault = true;
    return $Desc;
  }

  function Check(): void
  {
    $SID = session_id();
    // Lookup user record
    $Query = $this->Database->select('UserOnline', '*', 'SessionId="'.$SID.'"');
    if ($Query->num_rows > 0)
    {
      // Refresh time of last access
      $this->Database->update('UserOnline', '`SessionId`="'.$SID.'"', array('ActivityTime' => 'NOW()'));
    } else $this->Database->insert('UserOnline', array('SessionId' => $SID,
      'User' => null, 'LoginTime' => 'NOW()', 'ActivityTime' => 'NOW()',
      'IpAddress' => GetRemoteAddress(), 'HostName' => gethostbyaddr(GetRemoteAddress()),
      'ScriptName' => $_SERVER['PHP_SELF'], 'StayLogged' => 0, 'StayLoggedHash' => ''));

    // Logged permanently?
    if (array_key_exists('LoginHash', $_COOKIE))
    {
      $DbResult = $this->Database->query('SELECT * FROM `UserOnline` WHERE `User`='.$_COOKIE['LoginUserId'].
        ' AND `StayLogged`=1 AND SessionId!="'.$SID.'"');
      if ($DbResult->num_rows > 0)
      {
        $DbRow = $DbResult->fetch_assoc();
        if (sha1($_COOKIE['LoginUserId'].$DbRow['StayLoggedHash']) == $_COOKIE['LoginHash'])
        {
          $this->Database->query('DELETE FROM `UserOnline` WHERE `SessionId`="'.$SID.'"');
          $this->Database->query('UPDATE `UserOnline` SET `SessionId`="'.$SID.'" WHERE `Id`='.$DbRow['Id']);
        }
      }
    }

    // Check login
    $Query = $this->Database->select('UserOnline', '*', '`SessionId`="'.$SID.'"');
    $Row = $Query->fetch_assoc();
    if ($Row['User'] != '')
    {
      $Query = $this->Database->query('SELECT `User`.* FROM `User` WHERE `User`.`Id`='.$Row['User']);
      $this->User = $Query->fetch_assoc();
      $Result = USER_LOGGED;
    } else
    {
      $Query = $this->Database->select('User', '*', 'Id IS NULL');
      $this->User = array('Id' => null);
      $Result = USER_NOT_LOGGED;
    }

    // Remove nonactive users
    $DbResult = $this->Database->select('UserOnline', '`Id`, `User`', '(`ActivityTime` < DATE_SUB(NOW(), INTERVAL '.$this->OnlineStateTimeout.' SECOND)) AND (`StayLogged` = 0)');
    while ($DbRow = $DbResult->fetch_array())
    {
      $this->Database->delete('UserOnline', 'Id='.$DbRow['Id']);
      if ($DbRow['User'] != null) ModuleLog::Cast($this->System->GetModule('Log'))->NewRecord('User', 'Logout');
    }
    //$this->LoadPermission($this->User['Role']);

    // Role and permission
    //$this->LoadRoles();
  }

  function Register(string $Login, string $Password, string $Password2, string $Email, string $Name): string
  {
    if (($Email == '') || ($Login == '') || ($Password == '') || ($Password2 == '')  || ($Name == '')) $Result = DATA_MISSING;
    else if ($Password != $Password2) $Result = PASSWORDS_UNMATCHED;
    else
    {
      // Is user registred yet?
      $Query = $this->Database->select('User', '*', 'Login = "'.$Login.'"');
      if ($Query->num_rows > 0) $Result = LOGIN_USED;
      else
      {
        $Query = $this->Database->select('User', '*', 'Name = "'.$Name.'"');
        if ($Query->num_rows > 0) $Result = NAME_USED;
        else
        {
          $Query = $this->Database->select('User', '*', 'Email = "'.$Email.'"');
          if ($Query->num_rows > 0) $Result = EMAIL_USED;
          else
          {
            $PasswordHash = new PasswordHash();
            $Salt = $PasswordHash->GetSalt();
            $this->Database->insert('User', array('Name' => $Name, 'Login' => $Login,
              'Password' => $PasswordHash->Hash($Password, $Salt), 'Salt' => $Salt,
              'Email' => $Email, 'RegistrationTime' => 'NOW()',
              'Locked' => 1));
            $UserId = $this->Database->insert_id;
            $PermissionGroup = new PermissionGroup($this->System);
            $this->Database->insert('PermissionUserAssignment', array('User' => $UserId,
              'AssignedGroup' => $PermissionGroup->GetItemBySysName('registered-users')));

            $NewPassword = substr(sha1(strtoupper($Login)), 0, 7);

            // Send activation mail to user email
            $ServerURL = 'https://'.$this->System->Config['Web']['Host'].$this->System->Config['Web']['RootFolder'];
            $Mail = new Mail();
            $Mail->Subject = 'Registrace nového účtu';
            $Mail->AddBody('Provedli jste registraci nového účtu na serveru <a href="'.$ServerURL.'">'.$ServerURL.'"</a>.'.
              '<br/>\nPokud jste tak neučinili, měli by jste tento email ignorovat.<br/><br/>\n\n'.
              'Váš účet je: '.$Login."\n<br/>Pro dokončení registrace klikněte na tento odkaz: ".'<a href="'.
              $ServerURL.'/user/?Action=UserRegisterConfirm&User='.
              $UserId.'&H='.$NewPassword.'">'.$ServerURL.'/?Action=UserRegisterConfirm&User='.
              $UserId.'&H='.$NewPassword.'</a>.'."\n<br> \n\n'.
              '<br/><br/>Na tento email neodpovídejte.", 'text/html');
            $Mail->AddTo($Email, $Name);
            $Mail->From = $this->System->Config['Web']['Title'].' <noreplay@zdechov.net>';
            $Mail->Send();

            $Result = USER_REGISTRATED;
            ModuleLog::Cast($this->System->GetModule('Log'))->NewRecord('User', 'NewRegistration', $Login);
          }
        }
      }
    }
    return $Result;
  }

  function RegisterConfirm(string $Id, string $Hash): string
  {
    $DbResult = $this->Database->select('User', 'Id, Login, Password', 'Id = '.$Id);
    if ($DbResult->num_rows > 0)
    {
      $Row = $DbResult->fetch_array();
      $NewPassword = substr(sha1(strtoupper($Row['Login'])), 0, 7);
      if ($Hash == $NewPassword)
      {
        $this->Database->update('User', 'Id='.$Row['Id'], array('Locked' => 0));
        $Output = USER_REGISTRATION_CONFIRMED;
        ModuleLog::Cast($this->System->GetModule('Log'))->NewRecord('User', 'RegisterConfirm', 'Login='.
          $Row['Login'].', Id='.$Row['Id']);
      } else $Output = PASSWORDS_UNMATCHED;
    } else $Output = USER_NOT_FOUND;
    return $Output;
  }

  function Login(string $Login, string $Password, bool $StayLogged = false): string
  {
    if ($StayLogged) $StayLogged = 1; else $StayLogged = 0;
    $SID = session_id();
    $Query = $this->Database->select('User', '*', 'Login="'.$Login.'"');
    if ($Query->num_rows > 0)
    {
      $Row = $Query->fetch_assoc();
      $PasswordHash = new PasswordHash();
      if (!$PasswordHash->Verify($Password, $Row['Salt'], $Row['Password'])) $Result = BAD_PASSWORD;
      else if ($Row['Locked'] == 1) $Result = ACCOUNT_LOCKED;
      else
      {
        $this->Database->update('User', 'Id='.$Row['Id'], array('LastLoginTime' => 'NOW()',
          'LastIpAddress' => GetRemoteAddress()));
        $Hash = new PasswordHash();
        $StayLoggedSalt = $Hash->GetSalt();
        $this->Database->update('UserOnline', 'SessionId="'.$SID.'"', array(
          'User' => $Row['Id'], 'StayLogged' => $StayLogged, 'StayLoggedHash' => $StayLoggedSalt));
        if ($StayLogged)
        {
          setcookie('LoginUserId', $Row['Id'], time()+365*24*60*60, $this->System->Link('/'));
          setcookie('LoginHash', sha1($Row['Id'].$StayLoggedSalt), time()+365*24*60*60, $this->System->Link('/'));
        } else 
        {
          setcookie('LoginUserId', '', time() - 3600, $this->System->Link('/'));
          setcookie('LoginHash', '', time() - 3600, $this->System->Link('/'));
        }

        $Result = USER_LOGGED_IN;
        $this->Check();
        ModuleLog::Cast($this->System->GetModule('Log'))->NewRecord('User', 'Login', 'Login='.$Login.',Host='.gethostbyaddr(GetRemoteAddress()));
      }
    } else $Result = USER_NOT_REGISTRED;
    
    // Wait some minimal time if not able to log in to avoid brute forcing passwords
    if ($Result != USER_LOGGED_IN) sleep(1);

    return $Result;
  }

  function Logout(): string
  {
    $SID = session_id();
    $this->Database->update('UserOnline', 'SessionId="'.$SID.'"', array('User' => null));
    ModuleLog::Cast($this->System->GetModule('Log'))->NewRecord('User', 'Logout', $this->User['Login']);
    $this->Check();
    return USER_LOGGED_OUT;
  }

  function LoadRoles()
  {
    $this->Roles = array();
    $DbResult = $this->Database->select('UserRole', '*');
    while ($DbRow = $DbResult->fetch_array())
    {
      $this->Roles[] = $DbRow;
    }
  }

  function LoadPermission($Role)
  {
    $this->User['Permission'] = array();
    $DbResult = $this->Database->query('SELECT `UserRolePermission`.*, `PermissionOperation`.`Description` FROM `UserRolePermission` JOIN `PermissionOperation` ON `PermissionOperation`.`Id` = `UserRolePermission`.`Operation` WHERE `UserRolePermission`.`Role` = '.$Role);
    if ($DbResult->num_rows > 0)
    while ($DbRow = $DbResult->fetch_array())
    {
      $this->User['Permission'][$DbRow['Operation']] = $DbRow;
    }
  }

  function PermissionMatrix(): array
  {
    $Result = array();
    $DbResult = $this->Database->query('SELECT `UserRolePermission`.*, `PermissionOperation`.`Description`, `UserRole`.`Title` FROM `UserRolePermission` LEFT JOIN `PermissionOperation` ON `PermissionOperation`.`Id` = `UserRolePermission`.`Operation` LEFT JOIN `UserRole` ON `UserRole`.`Id` = `UserRolePermission`.`Role`');
    while ($DbRow = $DbResult->fetch_array())
    {
      $Value = '';
      if ($DbRow['Read']) $Value .= 'R';
      if ($DbRow['Write']) $Value .= 'W';
      $Result[$DbRow['Description']][$DbRow['Title']] = $Value;
    }
    return $Result;
  }

  function CheckGroupPermission(string $GroupId, string $OperationId): bool
  {    
    $PermissionExists = false;
    // First try to check cache group-group relation
    if (array_key_exists($GroupId, $this->PermissionGroupCache))
    {
      $PermissionExists = true;
    } else
    {
      $this->PermissionGroupCache[$GroupId] = array();

      // If no permission combination exists in cache, do new check of database items
      $DbResult = $this->Database->select('PermissionGroupAssignment', '*', '(`Group`="'.$GroupId.
        '") AND (`AssignedGroup` IS NOT NULL)');
      while ($DbRow = $DbResult->fetch_array())
      {
        $this->PermissionGroupCache[$GroupId][] = $DbRow;
      }
      $PermissionExists = true;
    }
    if ($PermissionExists)
    {
      foreach ($this->PermissionGroupCache[$GroupId] as $DbRow)
      {
        if ($DbRow['AssignedGroup'] != '')
        {
          if ($this->CheckGroupPermission($DbRow['AssignedGroup'], $OperationId) == true) return true;
        }
      }
    }

    // Check group-operation relation
    if (array_key_exists($GroupId.','.$OperationId, $this->PermissionGroupCacheOp))
    {
      $PermissionExists = true;
    } else
    {
      // If no permission combination exists in cache, do new check of database items
      $DbResult = $this->Database->select('PermissionGroupAssignment', '*', '`Group`="'.$GroupId.'" AND `AssignedOperation`="'.$OperationId.'"');
      if ($DbResult->num_rows > 0) $this->PermissionGroupCacheOp[$GroupId.','.$OperationId] = true;
        else $this->PermissionGroupCacheOp[$GroupId.','.$OperationId] = false;
      $PermissionExists = true;
    }
    if ($PermissionExists)
    {
      return $this->PermissionGroupCacheOp[$GroupId.','.$OperationId];
    }
    return false;
  }

  function CheckPermission(string $Module, string $Operation, string $ItemType = '', int $ItemIndex = 0): bool
  {
    // Get module id
    $DbResult = $this->Database->select('Module', 'Id', '`Name`="'.$Module.'"');
    if ($DbResult->num_rows > 0)
    {
      $DbRow = $DbResult->fetch_assoc();
      $ModuleId = $DbRow['Id'];
    } else return false;

    // First try to check cache
    if (in_array(array($Module, $Operation, $ItemType, $ItemType), $this->PermissionCache))
    {
      $OperationId = array_search(array($Module, $Operation, $ItemType, $ItemIndex), $this->PermissionCache);
      $PermissionExists = is_numeric($OperationId);
    } else
    {
      // If no permission combination exists in cache, do new check of database items
      $DbResult = $this->Database->select('PermissionOperation', 'Id', '(`Module`="'.$ModuleId.
        '") AND (`Item`="'.$ItemType.'") AND (`ItemId`='.$ItemIndex.') AND (`Operation`="'.$Operation.'")');
      if ($DbResult->num_rows > 0)
      {
        $DbRow = $DbResult->fetch_array();
        $OperationId = $DbRow['Id'];
        $this->PermissionCache[$DbRow['Id']] = array($Module, $Operation, $ItemType, $ItemIndex);
        $PermissionExists = true;
      } else
      {
        $this->PermissionCache[count($this->PermissionCache).'_'] = array($Module, $Operation, $ItemType, $ItemIndex);
        $PermissionExists = false;
      }
    }

    if ($PermissionExists)
    {      
      if ($this->User == null or $this->User['Id'] == null) $UserCondition = '(`User` IS NULL)';
        else $UserCondition = '(`User`="'.$this->User['Id'].'")';
      // Check user-operation relation
      $DbResult = $this->Database->select('PermissionUserAssignment', '*', $UserCondition.' AND (`AssignedOperation`="'.$OperationId.'")');
      if ($DbResult->num_rows > 0) return true;

      
      // Check user-group relation
      $DbResult = $this->Database->select('PermissionUserAssignment', 'AssignedGroup', '(`AssignedGroup` IS NOT NULL) AND '.$UserCondition);
      while ($DbRow = $DbResult->fetch_array())
      {
        if ($this->CheckGroupPermission($DbRow['AssignedGroup'], $OperationId) == true) return true;
      }
      return false;
    } else return false;
  }

  function PasswordRecoveryRequest(string $Login, string $Email): string
  {
    $DbResult = $this->Database->select('User', 'Login, Name, Id, Email, Password', '`Login`="'.$Login.'" AND `Email`="'.$Email.'"');
    if ($DbResult->num_rows > 0)
    {
      $Row = $DbResult->fetch_array();
      $NewPassword = substr(sha1(strtoupper($Row['Login'])), 0, 7);

      $ServerURL = 'https://'.$this->System->Config['Web']['Host'].$this->System->Config['Web']['RootFolder'];
      $Mail = new Mail();
      $Mail->Subject = 'Obnova hesla';
      $Mail->From = $this->System->Config['Web']['Title'].' <noreplay@zdechov.net>';
      $Mail->AddTo($Row['Email'], $Row['Name']);
      $Mail->AddBody('Požádali jste o zaslání nového hesla na serveru <a href="'.$ServerURL.'">'.$ServerURL.'"</a>.<br />\n'.
        "Pokud jste tak neučinili, měli by jste tento email ignorovat.<br /><br />\n\nVaše nové heslo k účtu ".
        $Row['Login'].' je: '.$NewPassword."\n<br/>".
        'Pro aktivaci tohoto hesla klikněte na <a href="'.$ServerURL.'/user/?Action=PasswordRecoveryConfirm&User='.
        $Row['Id'].'&H='.$Row['Password'].'&P='.$NewPassword.'">tento odkaz</a>.'."\n<br />".
        "Po přihlášení si prosím změňte heslo na nové.\n\n<br><br>Na tento email neodpovídejte.", 'text/html');
      $Mail->Send();

      $Output = USER_PASSWORD_RECOVERY_SUCCESS;
      ModuleLog::Cast($this->System->GetModule('Log'))->NewRecord('User', 'PasswordRecoveryRequest', 'Login='.$Login.',Email='.$Email);
    } else $Output = USER_PASSWORD_RECOVERY_FAIL;
    return $Output;
  }

  function PasswordRecoveryConfirm(string $Id, string $Hash, string $NewPassword): string
  {
    $DbResult = $this->Database->select('User', 'Id, Login, Password', 'Id = '.$Id);
    if ($DbResult->num_rows > 0)
    {
      $Row = $DbResult->fetch_array();
      $NewPassword2 = substr(sha1(strtoupper($Row['Login'])), 0, 7);
      if (($NewPassword == $NewPassword2) and ($Hash == $Row['Password']))
      {
        $PasswordHash = new PasswordHash();
        $Salt = $PasswordHash->GetSalt();
        $this->Database->update('User', 'Id='.$Row['Id'], array('Password' => $PasswordHash->Hash($NewPassword, $Salt),
          'Salt' => $Salt, 'Locked' => 0));
        $Output = USER_PASSWORD_RECOVERY_CONFIRMED;
        ModuleLog::Cast($this->System->GetModule('Log'))->NewRecord('User', 'PasswordRecoveryConfirm', 'Login='.$Row['Login']);
      } else $Output = PASSWORDS_UNMATCHED;
    } else $Output = USER_NOT_FOUND;
    return $Output;
  }

  function CheckToken(string $Module, string $Operation, string $Token): bool
  {
    $DbResult = $this->Database->select('APIToken', 'User', '`Token`="'.$Token.'"');
    if ($DbResult->num_rows > 0)
    {
      $DbRow = $DbResult->fetch_assoc();
      $User = new User($this->System);
      $User->User = array('Id' => $DbRow['User']);
      return $User->CheckPermission($Module, $Operation);
    } else return false;
  }
}

class UserOnline extends Model
{
  static function GetModelDesc(): ModelDesc
  {
    $Desc = new ModelDesc(self::GetClassName());
    $Desc->Memory = true;
    $Desc->AddReference('User', User::GetClassName(), true);
    $Desc->AddDateTime('ActivityTime');
    $Desc->AddDateTime('LoginTime');
    $Desc->AddString('SessionId');
    $Desc->AddString('IpAddress');
    $Desc->AddString('HostName');
    $Desc->AddString('ScriptName');
    $Desc->AddBoolean('StayLogged');
    $Desc->AddString('StayLoggedHash');
    return $Desc;
  }
}

class PermissionGroup extends Model
{
  static function GetModelDesc(): ModelDesc
  {
    $Desc = new ModelDesc(self::GetClassName());
    $Desc->AddString('Description');
    $Desc->AddString('SysName');
    $Desc->DefaultValuesMethod = 'GetDefaultValues';
    return $Desc;
  }

  static function GetDefaultValues(): array
  {
    return array(
      array('Id' => 1, 'Description' => 'Ostatní uživatelé', 'SysName' => 'other-users'),
      array('Id' => 2, 'Description' => 'Registrovaní uživatelé', 'SysName' => 'registered-users'),
      array('Id' => 3, 'Description' => 'Správci', 'SysName' => 'admins'),
    );
  }

  function GetItemBySysName(string $Name): int
  {
    $DbResult = $this->Database->select('PermissionGroup', 'Id', '`SysName`="'.$Name.'"');
    if ($DbResult->num_rows > 0)
    {
      $DbRow = $DbResult->fetch_assoc();
      return $DbRow['Id'];
    } else return 0;
  }
}

class PermissionGroupAssignment extends Model
{
  static function GetModelDesc(): ModelDesc
  {
    $Desc = new ModelDesc(self::GetClassName());
    $Desc->AddReference('Group', PermissionGroup::GetClassName());
    $Desc->AddReference('AssignedGroup', PermissionGroup::GetClassName(), true);
    $Desc->AddReference('AssignedOperation', PermissionOperation::GetClassName(), true);
    return $Desc;
  }
}

class PermissionOperation extends Model
{
  static function GetModelDesc(): ModelDesc
  {
    $Desc = new ModelDesc(self::GetClassName());
    $Desc->AddReference('Module', Module::GetClassName());
    $Desc->AddString('Operation');
    $Desc->AddString('Item');
    $Desc->AddInteger('ItemId');
    $Desc->Indices = array('Operation', 'Item', 'ItemId');
    return $Desc;
  }
}

class PermissionUserAssignment extends Model
{
  static function GetModelDesc(): ModelDesc
  {
    $Desc = new ModelDesc(self::GetClassName());
    $Desc->AddReference('User', User::GetClassName());
    $Desc->AddReference('AssignedGroup', PermissionGroup::GetClassName(), true);
    $Desc->AddReference('AssignedOperation', PermissionOperation::GetClassName(), true);
    return $Desc;
  }
}