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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 implementing OpenThread DNS-SD platform APIs.
 */

#ifndef OTBR_AGENT_POSIX_DNSSD_HPP_
#define OTBR_AGENT_POSIX_DNSSD_HPP_

#include "openthread-br/config.h"

#if OTBR_ENABLE_DNSSD_PLAT

#include <functional>
#include <string>

#include <openthread/instance.h>
#include <openthread/platform/dnssd.h>

#include "common/code_utils.hpp"
#include "common/dns_utils.hpp"
#include "host/thread_host.hpp"
#include "mdns/mdns.hpp"

namespace otbr {

/**
 * This class implements the DNS-SD platform.
 *
 */
class DnssdPlatform : public Mdns::StateObserver, private NonCopyable
{
public:
    /**
     * Initializes the `DnssdPlatform` instance
     *
     * @param[in] aPublisher   A reference to `Mdns::Publisher` to use.
     */
    DnssdPlatform(Mdns::Publisher &aPublisher);

    /**
     * Starts the `DnssdPlatform` module.
     */
    void Start(void);

    /**
     * Stops the `DnssdPlatform` module
     */
    void Stop(void);

    /**
     * Gets the singleton `DnssdPlatform` instance.
     *
     * @returns  A reference to the `DnssdPlatform` instance.
     */
    static DnssdPlatform &Get(void) { return *sDnssdPlatform; }

    typedef std::function<void(otPlatDnssdState)> DnssdStateChangeCallback;

    /**
     * Sets a Dnssd State changed callback.
     *
     * The main usage of this method is to call `otPlatDnssdStateHandleStateChange` to notify OT core about the change
     * when the dnssd state changes. We shouldn't directly call `otPlatDnssdStateHandleStateChange` in this module'
     * because it only fits the RCP case.
     *
     * @param[in] aCallback  The callback to be invoked when the dnssd state changes.
     */
    void SetDnssdStateChangedCallback(DnssdStateChangeCallback aCallback);

    //-----------------------------------------------------------------------------------------------------------------
    // `otPlatDnssd` APIs (see `openthread/include/openthread/platform/dnssd.h` for detailed documentation).

    typedef otPlatDnssdState                                   State;
    typedef otPlatDnssdService                                 Service;
    typedef otPlatDnssdHost                                    Host;
    typedef otPlatDnssdKey                                     Key;
    typedef otPlatDnssdRequestId                               RequestId;
    typedef std::function<void(otPlatDnssdRequestId, otError)> RegisterCallback;

    State GetState(void) const { return mState; }
    void  RegisterService(const Service &aService, RequestId aRequestId, RegisterCallback aCallback);
    void  UnregisterService(const Service &aService, RequestId aRequestId, RegisterCallback aCallback);
    void  RegisterHost(const Host &aHost, RequestId aRequestId, RegisterCallback aCallback);
    void  UnregisterHost(const Host &aHost, RequestId aRequestId, RegisterCallback aCallback);
    void  RegisterKey(const Key &aKey, RequestId aRequestId, RegisterCallback aCallback);
    void  UnregisterKey(const Key &aKey, RequestId aRequestId, RegisterCallback aCallback);

private:
    static constexpr State kStateReady   = OT_PLAT_DNSSD_READY;
    static constexpr State kStateStopped = OT_PLAT_DNSSD_STOPPED;

    void HandleMdnsState(Mdns::Publisher::State aState) override;

    void                            UpdateState(void);
    Mdns::Publisher::ResultCallback MakePublisherCallback(RequestId aRequestId, RegisterCallback aCallback);

    static std::string KeyNameFor(const Key &aKey);

    static DnssdPlatform *sDnssdPlatform;

    Mdns::Publisher         &mPublisher;
    State                    mState;
    bool                     mRunning;
    Mdns::Publisher::State   mPublisherState;
    DnssdStateChangeCallback mStateChangeCallback;
};

} // namespace otbr

#endif // OTBR_ENABLE_DNSSD_PLAT

#endif // OTBR_AGENT_POSIX_DNSSD_HPP_