/*
 *  Copyright (c) 2020, The OpenThread Authors.
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 *  modification, are permitted provided that the following conditions are met:
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the copyright holder nor the
 *     names of its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 */

/**
 * @file
 *   This file includes definitions for Dataset Updater.
 */

#ifndef DATASET_UPDATER_HPP_
#define DATASET_UPDATER_HPP_

#include "openthread-core-config.h"

#if (OPENTHREAD_CONFIG_DATASET_UPDATER_ENABLE || OPENTHREAD_CONFIG_CHANNEL_MANAGER_ENABLE) && OPENTHREAD_FTD

#include <openthread/dataset_updater.h>

#include "common/callback.hpp"
#include "common/locator.hpp"
#include "common/message.hpp"
#include "common/non_copyable.hpp"
#include "common/notifier.hpp"
#include "common/timer.hpp"
#include "meshcop/dataset.hpp"
#include "meshcop/meshcop_tlvs.hpp"

namespace ot {
namespace MeshCoP {

/**
 * Implements the Dataset Updater.
 */
class DatasetUpdater : public InstanceLocator, private NonCopyable
{
    friend class ot::Notifier;

public:
    /**
     * Default delay (in ms).
     */
    static constexpr uint32_t kDefaultDelay = OPENTHREAD_CONFIG_DATASET_UPDATER_DEFAULT_DELAY;

    /**
     * Initializes a `DatasetUpdater` object.
     *
     * @param[in]   aInstance  A reference to the OpenThread instance.
     */
    explicit DatasetUpdater(Instance &aInstance);

    /**
     * Represents the callback function pointer which is called when a Dataset update request finishes,
     * reporting success or failure status of the request.
     *
     * The function pointer has the syntax `void (*UpdaterCallback)(Error aError, void *aContext)`.
     */
    typedef otDatasetUpdaterCallback UpdaterCallback;

    /**
     * Requests an update to Operational Dataset.
     *
     * @p aDataset should contain the fields to be updated and their new value. It must not contain Active or Pending
     * Timestamp fields. The Delay field is optional, if not provided a default value (`kDefaultDelay`) would be used.
     *
     * @param[in]  aDataset                Dataset info containing fields to change.
     * @param[in]  aCallback               A callback to indicate when Dataset update request finishes.
     * @param[in]  aContext                An arbitrary context passed to callback.
     *
     * @retval kErrorNone           Dataset update started successfully (@p aCallback will be invoked on completion).
     * @retval kErrorInvalidState   Device is disabled or not fully configured (missing or incomplete Active Dataset).
     * @retval kErrorAlready        The @p aDataset fields already match the existing Active Dataset.
     * @retval kErrorInvalidArgs    The @p aDataset is not valid (contains Active or Pending Timestamp).
     * @retval kErrorBusy           Cannot start update, a previous one is ongoing.
     * @retval kErrorNoBufs         Could not allocated buffer to save Dataset.
     */
    Error RequestUpdate(const Dataset::Info &aDataset, UpdaterCallback aCallback, void *aContext);

    /**
     * Cancels an ongoing (if any) Operational Dataset update request.
     */
    void CancelUpdate(void);

    /**
     * Indicates whether there is an ongoing Operation Dataset update request.
     *
     * @retval TRUE    There is an ongoing update.
     * @retval FALSE   There is no ongoing update.
     */
    bool IsUpdateOngoing(void) const { return (mDataset != nullptr); }

private:
    Error RequestUpdate(Dataset &aDataset, UpdaterCallback aCallback, void *aContext);
    void  Finish(Error aError);
    void  HandleNotifierEvents(Events aEvents);
    void  HandleDatasetChanged(Dataset::Type aType);

    Message                  *mDataset;
    Callback<UpdaterCallback> mCallback;
};

} // namespace MeshCoP
} // namespace ot

#endif // (OPENTHREAD_CONFIG_DATASET_UPDATER_ENABLE || OPENTHREAD_CONFIG_CHANNEL_MANAGER_ENABLE) && OPENTHREAD_FTD

#endif // DATASET_UPDATER_HPP_