/*
 *
 *    Copyright (c) 2021 Project CHIP Authors
 *    All rights reserved.
 *
 *    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.
 */

/**
 *    @file
 *      This file defines the Delegate class that contains callbacks to
 *      establish a secure session and update status of the session establishment process.
 *
 */

#pragma once

#include <system/SystemClock.h>
#include <system/SystemPacketBuffer.h>
#include <transport/Session.h>
#include <transport/raw/MessageHeader.h>
#include <transport/raw/PeerAddress.h>

namespace chip {

enum class SessionEstablishmentStage : uint8_t
{
    kUnknown          = 0,
    kNotInKeyExchange = 1,
    kSentSigma1       = 2,
    kReceivedSigma1   = 3,
    kSentSigma2       = 4,
    kReceivedSigma2   = 5,
    kSentSigma3       = 6,
    kReceivedSigma3   = 7,
};

class DLL_EXPORT SessionEstablishmentDelegate
{
public:
    /**
     *   Called when session establishment fails with an error.  This will be
     *   called at most once per session establishment and will not be called if
     *   OnSessionEstablished is called.
     *
     *   This overload of OnSessionEstablishmentError is not called directly.
     *   It's only called from the default implementation of the two-argument
     *   overload.
     */
    virtual void OnSessionEstablishmentError(CHIP_ERROR error) {}

    /**
     *   Called when session establishment fails with an error and state at the
     *   failure. This will be called at most once per session establishment and
     *   will not be called if OnSessionEstablished is called.
     */
    virtual void OnSessionEstablishmentError(CHIP_ERROR error, SessionEstablishmentStage stage)
    {
        OnSessionEstablishmentError(error);
    }

    /**
     *   Called on start of session establishment process
     */
    virtual void OnSessionEstablishmentStarted() {}

    /**
     *   Called when the new secure session has been established.  This is
     *   mututally exclusive with OnSessionEstablishmentError for a give session
     *   establishment.
     */
    virtual void OnSessionEstablished(const SessionHandle & session) {}

    /**
     * Called when the responder has responded with a "busy" status code and
     * provided a requested delay.
     *
     * This call will be followed by an OnSessionEstablishmentError with
     * CHIP_ERROR_BUSY as the error.
     */
    virtual void OnResponderBusy(System::Clock::Milliseconds16 requestedDelay) {}

    virtual ~SessionEstablishmentDelegate() {}
};

} // namespace chip