/*
 * Copyright (c) 2021 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef KVSTORE_OBSERVER_H
#define KVSTORE_OBSERVER_H

#include <memory>
#include "change_notification.h"
#include "types.h"

namespace OHOS {
namespace DistributedKv {
// client implement this class to watch kvstore change.
class API_EXPORT KvStoreObserver {
public:
    enum ChangeOp : int32_t {
        OP_INSERT,
        OP_UPDATE,
        OP_DELETE,
        OP_BUTT,
    };
    using Keys = std::vector<std::string>[OP_BUTT];
    /**
     * @brief Constructor.
     */
    API_EXPORT KvStoreObserver() = default;

    /**
     * @brief Destructor.
     */
    API_EXPORT virtual ~KvStoreObserver() {}

    /**
     * @brief Would called when kvstore data change.
     *
     * client should override this function to receive change notification.
    */
    API_EXPORT virtual void OnChange(const ChangeNotification &changeNotification) {}

    /**
     * @brief Would called when kvstore data change.
     *
     * client should override this function to receive change notification.
    */
    API_EXPORT virtual void OnChange(const DataOrigin &origin, Keys &&keys) {}

    /**
     * @brief Would called when switch data change.
     *
     * client should override this function to receive change notification.
     */
    API_EXPORT virtual void OnSwitchChange(const SwitchNotification &notification) {}
};
}  // namespace DistributedKv
}  // namespace OHOS
#endif  // KVSTORE_OBSERVER_H