/*
 *
 *    Copyright (c) 2020 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 read handler for a CHIP Interaction Data model
 *
 */

#include <app/InteractionModelEngine.h>
#include <app/MessageDef/EventPath.h>
#include <app/ReadHandler.h>
#include <app/reporting/Engine.h>

namespace chip {
namespace app {
CHIP_ERROR ReadHandler::Init(InteractionModelDelegate * apDelegate)
{
    CHIP_ERROR err = CHIP_NO_ERROR;
    // Error if already initialized.
    VerifyOrExit(apDelegate != nullptr, err = CHIP_ERROR_INCORRECT_STATE);
    VerifyOrExit(mpExchangeCtx == nullptr, err = CHIP_ERROR_INCORRECT_STATE);
    mpExchangeCtx              = nullptr;
    mpDelegate                 = apDelegate;
    mSuppressResponse          = true;
    mpAttributeClusterInfoList = nullptr;
    mpEventClusterInfoList     = nullptr;
    mCurrentPriority           = PriorityLevel::Invalid;
    MoveToState(HandlerState::Initialized);

exit:
    ChipLogFunctError(err);
    return err;
}

void ReadHandler::Shutdown()
{
    InteractionModelEngine::GetInstance()->ReleaseClusterInfoList(mpAttributeClusterInfoList);
    InteractionModelEngine::GetInstance()->ReleaseClusterInfoList(mpEventClusterInfoList);
    AbortExistingExchangeContext();
    MoveToState(HandlerState::Uninitialized);
    mpDelegate                 = nullptr;
    mpAttributeClusterInfoList = nullptr;
    mpEventClusterInfoList     = nullptr;
    mCurrentPriority           = PriorityLevel::Invalid;
}

CHIP_ERROR ReadHandler::AbortExistingExchangeContext()
{
    if (mpExchangeCtx != nullptr)
    {
        mpExchangeCtx->Abort();
        mpExchangeCtx = nullptr;
    }

    return CHIP_NO_ERROR;
}

CHIP_ERROR ReadHandler::OnReadRequest(Messaging::ExchangeContext * apExchangeContext, System::PacketBufferHandle && aPayload)
{
    CHIP_ERROR err = CHIP_NO_ERROR;
    System::PacketBufferHandle response;

    mpExchangeCtx = apExchangeContext;
    err           = ProcessReadRequest(std::move(aPayload));
    SuccessOrExit(err);

exit:
    if (err != CHIP_NO_ERROR)
    {
        ChipLogFunctError(err);
        Shutdown();
    }

    return err;
}

CHIP_ERROR ReadHandler::SendReportData(System::PacketBufferHandle && aPayload)
{
    CHIP_ERROR err = CHIP_NO_ERROR;
    VerifyOrExit(mpExchangeCtx != nullptr, err = CHIP_ERROR_INCORRECT_STATE);

    err = mpExchangeCtx->SendMessage(Protocols::InteractionModel::MsgType::ReportData, std::move(aPayload));
exit:
    ChipLogFunctError(err);
    Shutdown();
    return err;
}

CHIP_ERROR ReadHandler::ProcessReadRequest(System::PacketBufferHandle && aPayload)
{
    CHIP_ERROR err = CHIP_NO_ERROR;
    System::PacketBufferTLVReader reader;

    ReadRequest::Parser readRequestParser;
    EventPathList::Parser eventPathListParser;
    AttributePathList::Parser attributePathListParser;

    reader.Init(std::move(aPayload));

    err = reader.Next();
    SuccessOrExit(err);

    err = readRequestParser.Init(reader);
    SuccessOrExit(err);
#if CHIP_CONFIG_IM_ENABLE_SCHEMA_CHECK
    err = readRequestParser.CheckSchemaValidity();
    SuccessOrExit(err);
#endif

    err = readRequestParser.GetAttributePathList(&attributePathListParser);
    if (err == CHIP_END_OF_TLV)
    {
        err = CHIP_NO_ERROR;
    }
    else
    {
        SuccessOrExit(err);
        err = ProcessAttributePathList(attributePathListParser);
    }
    SuccessOrExit(err);
    err = readRequestParser.GetEventPathList(&eventPathListParser);
    if (err == CHIP_END_OF_TLV)
    {
        err = CHIP_NO_ERROR;
    }
    else
    {
        SuccessOrExit(err);
        err = ProcessEventPathList(eventPathListParser);
    }
    SuccessOrExit(err);

    // if we have exhausted this container
    if (CHIP_END_OF_TLV == err)
    {
        err = CHIP_NO_ERROR;
    }

    MoveToState(HandlerState::Reportable);

    err = InteractionModelEngine::GetInstance()->GetReportingEngine().ScheduleRun();

exit:
    ChipLogFunctError(err);
    return err;
}

CHIP_ERROR ReadHandler::ProcessAttributePathList(AttributePathList::Parser & aAttributePathListParser)
{
    CHIP_ERROR err = CHIP_NO_ERROR;
    TLV::TLVReader reader;
    aAttributePathListParser.GetReader(&reader);

    while (CHIP_NO_ERROR == (err = reader.Next()))
    {
        VerifyOrExit(TLV::AnonymousTag == reader.GetTag(), err = CHIP_ERROR_INVALID_TLV_TAG);
        VerifyOrExit(TLV::kTLVType_List == reader.GetType(), err = CHIP_ERROR_WRONG_TLV_TYPE);
        ClusterInfo clusterInfo;
        AttributePath::Parser path;
        err = path.Init(reader);
        SuccessOrExit(err);
        err = path.GetNodeId(&(clusterInfo.mNodeId));
        SuccessOrExit(err);
        err = path.GetEndpointId(&(clusterInfo.mEndpointId));
        SuccessOrExit(err);
        err = path.GetClusterId(&(clusterInfo.mClusterId));
        SuccessOrExit(err);
        err = path.GetFieldId(&(clusterInfo.mFieldId));
        if (CHIP_NO_ERROR == err)
        {
            clusterInfo.mType = ClusterInfo::Type::kFieldIdValid;
        }
        else if (CHIP_END_OF_TLV == err)
        {
            err = path.GetListIndex(&(clusterInfo.mListIndex));
            SuccessOrExit(err);
            clusterInfo.mType = ClusterInfo::Type::kListIndexValid;
        }
        SuccessOrExit(err);
        err = InteractionModelEngine::GetInstance()->PushFront(mpAttributeClusterInfoList, clusterInfo);
        SuccessOrExit(err);
        mpAttributeClusterInfoList->SetDirty();
    }
    // if we have exhausted this container
    if (CHIP_END_OF_TLV == err)
    {
        err = CHIP_NO_ERROR;
    }

exit:
    ChipLogFunctError(err);
    return err;
}

CHIP_ERROR ReadHandler::ProcessEventPathList(EventPathList::Parser & aEventPathListParser)
{
    CHIP_ERROR err = CHIP_NO_ERROR;
    TLV::TLVReader reader;
    aEventPathListParser.GetReader(&reader);

    while (CHIP_NO_ERROR == (err = reader.Next()))
    {
        VerifyOrExit(TLV::AnonymousTag == reader.GetTag(), err = CHIP_ERROR_INVALID_TLV_TAG);
        VerifyOrExit(TLV::kTLVType_List == reader.GetType(), err = CHIP_ERROR_WRONG_TLV_TYPE);
        ClusterInfo clusterInfo;
        EventPath::Parser path;
        err = path.Init(reader);
        SuccessOrExit(err);
        err = path.GetNodeId(&(clusterInfo.mNodeId));
        SuccessOrExit(err);
        err = path.GetEndpointId(&(clusterInfo.mEndpointId));
        SuccessOrExit(err);
        err = path.GetClusterId(&(clusterInfo.mClusterId));
        SuccessOrExit(err);
        err = path.GetEventId(&(clusterInfo.mEventId));
        SuccessOrExit(err);
        clusterInfo.mType = ClusterInfo::Type::kEventIdValid;
        err               = InteractionModelEngine::GetInstance()->PushFront(mpEventClusterInfoList, clusterInfo);
        SuccessOrExit(err);
    }

    // if we have exhausted this container
    if (CHIP_END_OF_TLV == err)
    {
        err = CHIP_NO_ERROR;
    }

exit:
    ChipLogFunctError(err);
    return err;
}

const char * ReadHandler::GetStateStr() const
{
#if CHIP_DETAIL_LOGGING
    switch (mState)
    {
    case HandlerState::Uninitialized:
        return "Uninitialized";

    case HandlerState::Initialized:
        return "Initialized";

    case HandlerState::Reportable:
        return "Reportable";
    }
#endif // CHIP_DETAIL_LOGGING
    return "N/A";
}

void ReadHandler::MoveToState(const HandlerState aTargetState)
{
    mState = aTargetState;
    ChipLogDetail(DataManagement, "IM RH moving to [%s]", GetStateStr());
}

bool ReadHandler::CheckEventClean(EventManagement & aEventManager)
{
    if (mCurrentPriority == PriorityLevel::Invalid)
    {
        // Upload is not in middle, previous mLastScheduledEventNumber is not valid, Check for new events, and set a checkpoint
        for (size_t index = 0; index < ArraySize(mSelfProcessedEvents); index++)
        {
            EventNumber lastEventNumber = aEventManager.GetLastEventNumber(static_cast<PriorityLevel>(index));
            if ((lastEventNumber != 0) && (lastEventNumber >= mSelfProcessedEvents[index]))
            {
                // We have more events. snapshot last event IDs
                aEventManager.SetScheduledEventEndpoint(&(mLastScheduledEventNumber[0]));
                // initialize the next priority level to transfer
                MoveToNextScheduledDirtyPriority();
                return false;
            }
        }
        return true;
    }
    else
    {
        // Upload is in middle, previous mLastScheduledEventNumber is still valid, recheck via MoveToNextScheduledDirtyPriority,
        // if finally mCurrentPriority is invalid, it means no more event
        MoveToNextScheduledDirtyPriority();
        return mCurrentPriority == PriorityLevel::Invalid;
    }
}

void ReadHandler::MoveToNextScheduledDirtyPriority()
{
    for (uint8_t i = 0; i < ArraySize(mSelfProcessedEvents); i++)
    {
        if ((mLastScheduledEventNumber[i] != 0) && mSelfProcessedEvents[i] <= mLastScheduledEventNumber[i])
        {
            mCurrentPriority = static_cast<PriorityLevel>(i);
            return;
        }
    }

    mCurrentPriority = PriorityLevel::Invalid;
}
} // namespace app
} // namespace chip