class AdminNegotiator

class AdminNegotiator implements ThemeNegotiatorInterface {
    use DeprecatedServicePropertyTrait;
    
    /**
     * The service properties that should raise a deprecation error.
     */
    private array $deprecatedProperties = [
        'entityTypeManager' => 'entity_type.manager',
    ];
    
    /**
     * The current user.
     *
     * @var \Drupal\Core\Session\AccountInterface
     */
    protected $user;
    
    /**
     * The config factory.
     *
     * @var \Drupal\Core\Config\ConfigFactoryInterface
     */
    protected $configFactory;
    
    /**
     * The route admin context to determine whether a route is an admin one.
     *
     * @var \Drupal\Core\Routing\AdminContext
     */
    protected $adminContext;
    
    /**
     * Creates a new AdminNegotiator instance.
     *
     * @param \Drupal\Core\Session\AccountInterface $user
     *   The current user.
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   The config factory.
     * @param \Drupal\Core\Routing\AdminContext|EntityTypeManagerInterface $admin_context
     *   The route admin context to determine whether the route is an admin one.
     */
    public function __construct(AccountInterface $user, ConfigFactoryInterface $config_factory, AdminContext|EntityTypeManagerInterface $admin_context) {
        $this->user = $user;
        $this->configFactory = $config_factory;
        if ($admin_context instanceof EntityTypeManagerInterface) {
            $deprecated_service_name = EntityTypeManagerInterface::class;
            @trigger_error("Passing the {$deprecated_service_name} (entity_type.manager service) to AdminNegotiator is deprecated in drupal:11.2.0 and will be removed in drupal:12.0.0. There is no replacement for this service, as it is not used. See https://www.drupal.org/project/drupal/issues/3501727", E_USER_DEPRECATED);
            $this->adminContext = \Drupal::service('router.admin_context');
        }
        else {
            $this->adminContext = $admin_context;
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function applies(RouteMatchInterface $route_match) {
        $is_admin_route = $this->adminContext
            ->isAdminRoute($route_match->getRouteObject());
        return $is_admin_route && $this->user
            ->hasPermission('view the administration theme');
    }
    
    /**
     * {@inheritdoc}
     */
    public function determineActiveTheme(RouteMatchInterface $route_match) {
        return $this->configFactory
            ->get('system.theme')
            ->get('admin') ?: NULL;
    }

}