/*
 *  Copyright (c) 2016, The OpenThread Authors.
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 *  1. Redistributions of source code must retain the above copyright
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 *  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
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 */

/**
 * @file
 *   This file implements the PAN ID Query Server.
 */

#include "panid_query_server.hpp"

#include "coap/coap_message.hpp"
#include "common/code_utils.hpp"
#include "common/debug.hpp"
#include "common/instance.hpp"
#include "common/locator-getters.hpp"
#include "common/logging.hpp"
#include "meshcop/meshcop.hpp"
#include "meshcop/meshcop_tlvs.hpp"
#include "thread/thread_netif.hpp"
#include "thread/thread_uri_paths.hpp"

namespace ot {

PanIdQueryServer::PanIdQueryServer(Instance &aInstance)
    : InstanceLocator(aInstance)
    , mChannelMask(0)
    , mPanId(Mac::kPanIdBroadcast)
    , mTimer(aInstance, &PanIdQueryServer::HandleTimer, this)
    , mPanIdQuery(OT_URI_PATH_PANID_QUERY, &PanIdQueryServer::HandleQuery, this)
{
    Get<Coap::Coap>().AddResource(mPanIdQuery);
}

void PanIdQueryServer::HandleQuery(void *aContext, otMessage *aMessage, const otMessageInfo *aMessageInfo)
{
    static_cast<PanIdQueryServer *>(aContext)->HandleQuery(*static_cast<Coap::Message *>(aMessage),
                                                           *static_cast<const Ip6::MessageInfo *>(aMessageInfo));
}

void PanIdQueryServer::HandleQuery(Coap::Message &aMessage, const Ip6::MessageInfo &aMessageInfo)
{
    MeshCoP::PanIdTlv panId;
    Ip6::MessageInfo  responseInfo(aMessageInfo);
    uint32_t          mask;

    VerifyOrExit(aMessage.GetCode() == OT_COAP_CODE_POST);
    VerifyOrExit((mask = MeshCoP::ChannelMaskTlv::GetChannelMask(aMessage)) != 0);

    SuccessOrExit(MeshCoP::Tlv::GetTlv(aMessage, MeshCoP::Tlv::kPanId, sizeof(panId), panId));
    VerifyOrExit(panId.IsValid());

    mChannelMask  = mask;
    mCommissioner = aMessageInfo.GetPeerAddr();
    mPanId        = panId.GetPanId();
    mTimer.Start(kScanDelay);

    if (aMessage.IsConfirmable() && !aMessageInfo.GetSockAddr().IsMulticast())
    {
        SuccessOrExit(Get<Coap::Coap>().SendEmptyAck(aMessage, responseInfo));
        otLogInfoMeshCoP("sent panid query response");
    }

exit:
    return;
}

void PanIdQueryServer::HandleScanResult(Mac::ActiveScanResult *aScanResult, void *aContext)
{
    static_cast<PanIdQueryServer *>(aContext)->HandleScanResult(aScanResult);
}

void PanIdQueryServer::HandleScanResult(Mac::ActiveScanResult *aScanResult)
{
    if (aScanResult != NULL)
    {
        if (aScanResult->mPanId == mPanId)
        {
            mChannelMask |= 1 << aScanResult->mChannel;
        }
    }
    else if (mChannelMask != 0)
    {
        SendConflict();
    }
}

otError PanIdQueryServer::SendConflict(void)
{
    otError                 error = OT_ERROR_NONE;
    MeshCoP::ChannelMaskTlv channelMask;
    MeshCoP::PanIdTlv       panId;
    Ip6::MessageInfo        messageInfo;
    Coap::Message *         message;

    VerifyOrExit((message = MeshCoP::NewMeshCoPMessage(Get<Coap::Coap>())) != NULL, error = OT_ERROR_NO_BUFS);

    SuccessOrExit(error = message->Init(OT_COAP_TYPE_CONFIRMABLE, OT_COAP_CODE_POST, OT_URI_PATH_PANID_CONFLICT));
    SuccessOrExit(error = message->SetPayloadMarker());

    channelMask.Init();
    channelMask.SetChannelMask(mChannelMask);
    SuccessOrExit(error = channelMask.AppendTo(*message));

    panId.Init();
    panId.SetPanId(mPanId);
    SuccessOrExit(error = panId.AppendTo(*message));

    messageInfo.SetSockAddr(Get<Mle::MleRouter>().GetMeshLocal16());
    messageInfo.SetPeerAddr(mCommissioner);
    messageInfo.SetPeerPort(kCoapUdpPort);
    SuccessOrExit(error = Get<Coap::Coap>().SendMessage(*message, messageInfo));

    otLogInfoMeshCoP("sent panid conflict");

exit:

    if (error != OT_ERROR_NONE && message != NULL)
    {
        message->Free();
    }

    return error;
}

void PanIdQueryServer::HandleTimer(Timer &aTimer)
{
    aTimer.GetOwner<PanIdQueryServer>().HandleTimer();
}

void PanIdQueryServer::HandleTimer(void)
{
    Get<Mac::Mac>().ActiveScan(mChannelMask, 0, HandleScanResult, this);
    mChannelMask = 0;
}

} // namespace ot