some big beautfiul update

application/Espo/Classes/FieldValidators/WorkingTimeRange/Calendars/OnlyIfNoUsers.php

@@ -0,0 +1,55 @@
+<?php
+/************************************************************************
+ * This file is part of EspoCRM.
+ *
+ * EspoCRM – Open Source CRM application.
+ * Copyright (C) 2014-2026 EspoCRM, Inc.
+ * Website: https://www.espocrm.com
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ *
+ * The interactive user interfaces in modified source and object code versions
+ * of this program must display Appropriate Legal Notices, as required under
+ * Section 5 of the GNU Affero General Public License version 3.
+ *
+ * In accordance with Section 7(b) of the GNU Affero General Public License version 3,
+ * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
+ ************************************************************************/
+
+namespace Espo\Classes\FieldValidators\WorkingTimeRange\Calendars;
+
+use Espo\Core\FieldValidation\Validator;
+use Espo\Core\FieldValidation\Validator\Data;
+use Espo\Core\FieldValidation\Validator\Failure;
+use Espo\Entities\WorkingTimeRange;
+use Espo\ORM\Entity;
+
+/**
+ * @implements Validator<WorkingTimeRange>
+ */
+class OnlyIfNoUsers implements Validator
+{
+    public function validate(Entity $entity, string $field, Data $data): ?Failure
+    {
+        if ($entity->getCalendars()->getCount() === 0) {
+            return null;
+        }
+
+        if ($entity->getUsers()->getCount() === 0) {
+            return null;
+        }
+
+        return Failure::create();
+    }
+}