/*
 *
 *    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.
 */
#include <utility>

#include <app-common/zap-generated/cluster-objects.h>
#include <app/InteractionModelEngine.h>
#include <app/MessageDef/StatusResponseMessage.h>
#include <app/reporting/tests/MockReportScheduler.h>
#include <app/tests/AppTestContext.h>
#include <app/tests/test-interaction-model-api.h>
#include <app/util/mock/MockNodeConfig.h>
#include <credentials/GroupDataProviderImpl.h>
#include <crypto/CHIPCryptoPAL.h>
#include <crypto/DefaultSessionKeystore.h>
#include <lib/core/CHIPCore.h>
#include <lib/core/ErrorStr.h>
#include <lib/core/StringBuilderAdapters.h>
#include <lib/core/TLV.h>
#include <lib/core/TLVDebug.h>
#include <lib/core/TLVUtilities.h>
#include <lib/support/TestGroupData.h>
#include <lib/support/TestPersistentStorageDelegate.h>
#include <lib/support/tests/ExtraPwTestMacros.h>
#include <messaging/ExchangeContext.h>
#include <messaging/Flags.h>
#include <pw_unit_test/framework.h>

namespace {

constexpr chip::DataVersion kAcceptedDataVersion = 5;
constexpr uint16_t kMaxGroupsPerFabric           = 5;
constexpr uint16_t kMaxGroupKeysPerFabric        = 8;

chip::TestPersistentStorageDelegate gTestStorage;
chip::Crypto::DefaultSessionKeystore gSessionKeystore;
chip::Credentials::GroupDataProviderImpl gGroupsProvider(kMaxGroupsPerFabric, kMaxGroupKeysPerFabric);

} // namespace

namespace chip {
namespace app {

using namespace chip::Testing;

const MockNodeConfig & TestMockNodeConfig()
{
    using namespace Clusters::Globals::Attributes;

    // clang-format off
    static const MockNodeConfig config({
        MockEndpointConfig(kRootEndpointId, {
            MockClusterConfig(Clusters::IcdManagement::Id, {
                ClusterRevision::Id, FeatureMap::Id,
                Clusters::IcdManagement::Attributes::OperatingMode::Id,
            }),
        }),
        MockEndpointConfig(kTestEndpointId, {
            MockClusterConfig(Clusters::UnitTesting::Id, {
                ClusterRevision::Id, FeatureMap::Id,
                Clusters::UnitTesting::Attributes::Boolean::Id,
                Clusters::UnitTesting::Attributes::Int16u::Id,
                Clusters::UnitTesting::Attributes::ListFabricScoped::Id,
                Clusters::UnitTesting::Attributes::ListStructOctetString::Id,
            }),
        }),
        MockEndpointConfig(kMockEndpoint1, {
            MockClusterConfig(MockClusterId(1), {
                ClusterRevision::Id, FeatureMap::Id,
            }, {
                MockEventId(1), MockEventId(2),
            }),
            MockClusterConfig(MockClusterId(2), {
                ClusterRevision::Id, FeatureMap::Id, MockAttributeId(1),
            }),
        }),
        MockEndpointConfig(kMockEndpoint2, {
            MockClusterConfig(MockClusterId(1), {
                ClusterRevision::Id, FeatureMap::Id,
            }),
            MockClusterConfig(MockClusterId(2), {
                ClusterRevision::Id, FeatureMap::Id, MockAttributeId(1), MockAttributeId(2),
            }),
            MockClusterConfig(MockClusterId(3), {
                ClusterRevision::Id, FeatureMap::Id, MockAttributeId(1), MockAttributeId(2), MockAttributeId(3),
            }),
        }),
        MockEndpointConfig(kMockEndpoint3, {
            MockClusterConfig(MockClusterId(1), {
                ClusterRevision::Id, FeatureMap::Id, MockAttributeId(1),
            }),
            MockClusterConfig(MockClusterId(2), {
                ClusterRevision::Id, FeatureMap::Id, MockAttributeId(1), MockAttributeId(2), MockAttributeId(3), MockAttributeId(4),
            }),
            MockClusterConfig(MockClusterId(3), {
                ClusterRevision::Id, FeatureMap::Id,
            }),
            MockClusterConfig(MockClusterId(4), {
                ClusterRevision::Id, FeatureMap::Id,
            }),
        }),
        /// For `TestWriteRoundtripWithClusterObjects` where path 2/3/4 is used
        MockEndpointConfig(2, {
            MockClusterConfig(3, {4}),
        })
    });
    // clang-format on
    return config;
}

class TestWriteInteraction : public chip::Testing::AppContext
{
public:
    void SetUp() override
    {
        AppContext::SetUp();

        gTestStorage.ClearStorage();
        gGroupsProvider.SetStorageDelegate(&gTestStorage);
        gGroupsProvider.SetSessionKeystore(&gSessionKeystore);
        ASSERT_EQ(gGroupsProvider.Init(), CHIP_NO_ERROR);
        chip::Credentials::SetGroupDataProvider(&gGroupsProvider);

        uint8_t buf[sizeof(chip::CompressedFabricId)];
        chip::MutableByteSpan span(buf);
        ASSERT_EQ(GetBobFabric()->GetCompressedFabricIdBytes(span), CHIP_NO_ERROR);
        ASSERT_EQ(chip::GroupTesting::InitData(&gGroupsProvider, GetBobFabricIndex(), span), CHIP_NO_ERROR);

        mOldProvider = InteractionModelEngine::GetInstance()->SetDataModelProvider(&TestImCustomDataModel::Instance());
        chip::Testing::SetMockNodeConfig(TestMockNodeConfig());
    }
    void TearDown() override
    {
        chip::Testing::ResetMockNodeConfig();
        InteractionModelEngine::GetInstance()->SetDataModelProvider(mOldProvider);
        chip::Credentials::GroupDataProvider * provider = chip::Credentials::GetGroupDataProvider();
        if (provider != nullptr)
        {
            provider->Finish();
        }
        AppContext::TearDown();
    }

    enum class EncodingMethod
    {
        Standard,      // Encoding using WriteClient::EncodeAttribute()
        PreencodedTLV, // Encoding using WriteClient::PutPreencodedAttribute()
    };

    void TestWriteClient();
    void TestWriteClientGroup();
    void TestWriteHandlerReceiveInvalidMessage();
    void TestWriteHandlerReceiveEmptyWriteRequest();
    void TestWriteInvalidMessage1();
    void TestWriteInvalidMessage2();
    void TestWriteInvalidMessage3();
    void TestWriteInvalidMessage4();
    void TestWriteInvalidMessage5();
    void TestWriteClientSuppressResponseFlowWithInvalidAttribute();
    void TestSuppressedChunkedWriteDoesNotLeakHandler();
    void TestWriteClientRejectsSuppressedChunkedWrite();

    static void AddAttributeDataIB(WriteClient & aWriteClient, EncodingMethod encoding);
    static void AddInvalidAttributeDataIB(WriteClient & aWriteClient, EncodingMethod encoding);
    static void AddAttributeStatus(WriteHandler & aWriteHandler);
    static void GenerateWriteRequest(bool aIsTimedWrite, System::PacketBufferHandle & aPayload);
    static void GenerateSuppressResponseChunkedWriteRequest(System::PacketBufferHandle & aPayload);
    static void GenerateWriteResponse(System::PacketBufferHandle & aPayload);

private:
    chip::app::DataModel::Provider * mOldProvider = nullptr;
};

class TestExchangeDelegate : public Messaging::ExchangeDelegate
{
public:
    Protocols::InteractionModel::Status mLastStatus = Protocols::InteractionModel::Status::Success;
    bool mLastStatusParsedSuccessfully              = false;

private:
    CHIP_ERROR UpdateLastStatus(System::PacketBufferHandle && payload)
    {
        StatusResponseMessage::Parser response;
        System::PacketBufferTLVReader reader;
        reader.Init(std::move(payload));
        ReturnErrorOnFailure(response.Init(reader));
        ReturnErrorOnFailure(response.GetStatus(mLastStatus));
        return CHIP_NO_ERROR;
    }

    CHIP_ERROR OnMessageReceived(Messaging::ExchangeContext * ec, const PayloadHeader & payloadHeader,
                                 System::PacketBufferHandle && payload) override
    {
        if (payloadHeader.HasMessageType(Protocols::InteractionModel::MsgType::StatusResponse))
        {
            CHIP_ERROR err                = UpdateLastStatus(std::move(payload));
            mLastStatusParsedSuccessfully = (err == CHIP_NO_ERROR);
        }
        return CHIP_NO_ERROR;
    }

    void OnResponseTimeout(Messaging::ExchangeContext * ec) override {}
};

class TestWriteClientCallback : public chip::app::WriteClient::Callback
{
public:
    void ResetCounter() { mOnSuccessCalled = mOnErrorCalled = mOnDoneCalled = 0; }
    void OnResponse(const WriteClient * apWriteClient, const chip::app::ConcreteDataAttributePath & path, StatusIB status) override
    {
        mStatus = status;
        mOnSuccessCalled++;
    }
    void OnError(const WriteClient * apWriteClient, CHIP_ERROR chipError) override
    {
        mOnErrorCalled++;
        mLastErrorReason = app::StatusIB(chipError);
        mError           = chipError;
    }
    void OnDone(WriteClient * apWriteClient) override { mOnDoneCalled++; }

    int mOnSuccessCalled = 0;
    int mOnErrorCalled   = 0;
    int mOnDoneCalled    = 0;
    StatusIB mStatus;
    StatusIB mLastErrorReason;
    CHIP_ERROR mError = CHIP_NO_ERROR;
};

void TestWriteInteraction::AddAttributeDataIB(WriteClient & aWriteClient, EncodingMethod encoding = EncodingMethod::Standard)
{
    AttributePathParams attributePathParams;
    bool attributeValue              = true;
    attributePathParams.mEndpointId  = kTestEndpointId;
    attributePathParams.mClusterId   = Clusters::UnitTesting::Id;
    attributePathParams.mAttributeId = Clusters::UnitTesting::Attributes::Boolean::Id;

    switch (encoding)
    {
    case EncodingMethod::Standard:

        EXPECT_EQ(aWriteClient.EncodeAttribute(attributePathParams, attributeValue), CHIP_NO_ERROR);
        break;

    case EncodingMethod::PreencodedTLV:

        // Encode AttributeData into TLV
        uint8_t buffer[5];
        TLV::TLVWriter writer;
        writer.Init(buffer, sizeof(buffer));
        TLV::TLVType outerContainer;

        EXPECT_EQ(CHIP_NO_ERROR, writer.StartContainer(TLV::AnonymousTag(), TLV::kTLVType_Structure, outerContainer));
        EXPECT_EQ(CHIP_NO_ERROR, writer.PutBoolean(TLV::ContextTag(1), attributeValue));
        EXPECT_EQ(CHIP_NO_ERROR, writer.EndContainer(outerContainer));

        // Put Preencoded Data into AttributeDataIB
        TLV::TLVReader reader;
        reader.Init(buffer, writer.GetLengthWritten());
        EXPECT_SUCCESS(reader.Next());
        EXPECT_EQ(aWriteClient.PutPreencodedAttribute(ConcreteDataAttributePath(attributePathParams.mEndpointId,
                                                                                attributePathParams.mClusterId,
                                                                                attributePathParams.mAttributeId),
                                                      reader),
                  CHIP_NO_ERROR);
    }
}

void TestWriteInteraction::AddInvalidAttributeDataIB(WriteClient & aWriteClient, EncodingMethod encoding)
{
    AttributePathParams attributePathParams;
    bool attributeValue              = true;
    attributePathParams.mEndpointId  = kTestEndpointId;
    attributePathParams.mClusterId   = Clusters::UnitTesting::Id;
    attributePathParams.mAttributeId = 9999; // Invalid attribute ID

    switch (encoding)
    {
    case EncodingMethod::Standard:

        EXPECT_EQ(aWriteClient.EncodeAttribute(attributePathParams, attributeValue), CHIP_NO_ERROR);
        break;

    case EncodingMethod::PreencodedTLV:

        // Encode AttributeData into TLV
        uint8_t buffer[5];
        TLV::TLVWriter writer;
        writer.Init(buffer, sizeof(buffer));
        TLV::TLVType outerContainer;

        EXPECT_EQ(CHIP_NO_ERROR, writer.StartContainer(TLV::AnonymousTag(), TLV::kTLVType_Structure, outerContainer));
        EXPECT_EQ(CHIP_NO_ERROR, writer.PutBoolean(TLV::ContextTag(1), attributeValue));
        EXPECT_EQ(CHIP_NO_ERROR, writer.EndContainer(outerContainer));

        // Put Preencoded Data into AttributeDataIB
        TLV::TLVReader reader;
        reader.Init(buffer, writer.GetLengthWritten());
        EXPECT_SUCCESS(reader.Next());
        EXPECT_EQ(aWriteClient.PutPreencodedAttribute(ConcreteDataAttributePath(attributePathParams.mEndpointId,
                                                                                attributePathParams.mClusterId,
                                                                                attributePathParams.mAttributeId),
                                                      reader),
                  CHIP_NO_ERROR);
    }
}

void TestWriteInteraction::AddAttributeStatus(WriteHandler & aWriteHandler)
{
    ConcreteAttributePath attributePath(2, 3, 4);

    EXPECT_EQ(aWriteHandler.AddStatus(attributePath, Protocols::InteractionModel::Status::Success), CHIP_NO_ERROR);
}

void TestWriteInteraction::GenerateWriteRequest(bool aIsTimedWrite, System::PacketBufferHandle & aPayload)
{
    System::PacketBufferTLVWriter writer;
    writer.Init(std::move(aPayload));

    WriteRequestMessage::Builder writeRequestBuilder;
    EXPECT_EQ(writeRequestBuilder.Init(&writer), CHIP_NO_ERROR);
    writeRequestBuilder.TimedRequest(aIsTimedWrite);
    EXPECT_EQ(writeRequestBuilder.GetError(), CHIP_NO_ERROR);
    AttributeDataIBs::Builder & attributeDataIBsBuilder = writeRequestBuilder.CreateWriteRequests();
    EXPECT_EQ(writeRequestBuilder.GetError(), CHIP_NO_ERROR);
    AttributeDataIB::Builder & attributeDataIBBuilder = attributeDataIBsBuilder.CreateAttributeDataIBBuilder();
    EXPECT_EQ(attributeDataIBsBuilder.GetError(), CHIP_NO_ERROR);

    attributeDataIBBuilder.DataVersion(0);
    EXPECT_EQ(attributeDataIBBuilder.GetError(), CHIP_NO_ERROR);
    AttributePathIB::Builder & attributePathBuilder = attributeDataIBBuilder.CreatePath();
    EXPECT_EQ(attributePathBuilder.GetError(), CHIP_NO_ERROR);
    EXPECT_EQ(attributePathBuilder.Node(1)
                  .Endpoint(2)
                  .Cluster(3)
                  .Attribute(4)
                  .ListIndex(DataModel::Nullable<ListIndex>())
                  .EndOfAttributePathIB(),
              CHIP_NO_ERROR);

    // Construct attribute data
    {
        chip::TLV::TLVWriter * pWriter = attributeDataIBBuilder.GetWriter();
        chip::TLV::TLVType dummyType   = chip::TLV::kTLVType_NotSpecified;
        EXPECT_EQ(
            pWriter->StartContainer(chip::TLV::ContextTag(AttributeDataIB::Tag::kData), chip::TLV::kTLVType_Structure, dummyType),
            CHIP_NO_ERROR);

        EXPECT_EQ(pWriter->PutBoolean(chip::TLV::ContextTag(1), true), CHIP_NO_ERROR);

        EXPECT_EQ(pWriter->EndContainer(dummyType), CHIP_NO_ERROR);
    }

    EXPECT_SUCCESS(attributeDataIBBuilder.EndOfAttributeDataIB());
    EXPECT_EQ(attributeDataIBBuilder.GetError(), CHIP_NO_ERROR);

    EXPECT_SUCCESS(attributeDataIBsBuilder.EndOfAttributeDataIBs());
    EXPECT_EQ(attributeDataIBsBuilder.GetError(), CHIP_NO_ERROR);
    EXPECT_SUCCESS(writeRequestBuilder.EndOfWriteRequestMessage());
    EXPECT_EQ(writeRequestBuilder.GetError(), CHIP_NO_ERROR);

    EXPECT_EQ(writer.Finalize(&aPayload), CHIP_NO_ERROR);
}

// Builds a single WriteRequest that combines SuppressResponse=true with MoreChunkedMessages=true on one valid
// AttributeDataIB. A conformant WriteClient never emits this combination; it is constructed directly here to
// exercise the first-chunk handler lifecycle on the receive path.
void TestWriteInteraction::GenerateSuppressResponseChunkedWriteRequest(System::PacketBufferHandle & aPayload)
{
    System::PacketBufferTLVWriter writer;
    writer.Init(std::move(aPayload));

    WriteRequestMessage::Builder writeRequestBuilder;
    EXPECT_SUCCESS(writeRequestBuilder.Init(&writer));
    writeRequestBuilder.SuppressResponse(true);
    writeRequestBuilder.TimedRequest(false);
    EXPECT_SUCCESS(writeRequestBuilder.GetError());
    AttributeDataIBs::Builder & attributeDataIBsBuilder = writeRequestBuilder.CreateWriteRequests();
    EXPECT_SUCCESS(writeRequestBuilder.GetError());
    AttributeDataIB::Builder & attributeDataIBBuilder = attributeDataIBsBuilder.CreateAttributeDataIBBuilder();
    EXPECT_SUCCESS(attributeDataIBsBuilder.GetError());

    attributeDataIBBuilder.DataVersion(0);
    EXPECT_SUCCESS(attributeDataIBBuilder.GetError());
    AttributePathIB::Builder & attributePathBuilder = attributeDataIBBuilder.CreatePath();
    EXPECT_SUCCESS(attributePathBuilder.GetError());
    EXPECT_SUCCESS(attributePathBuilder.Node(1)
                       .Endpoint(2)
                       .Cluster(3)
                       .Attribute(4)
                       .ListIndex(DataModel::Nullable<ListIndex>())
                       .EndOfAttributePathIB());

    {
        chip::TLV::TLVWriter * pWriter = attributeDataIBBuilder.GetWriter();
        chip::TLV::TLVType dummyType   = chip::TLV::kTLVType_NotSpecified;
        EXPECT_SUCCESS(
            pWriter->StartContainer(chip::TLV::ContextTag(AttributeDataIB::Tag::kData), chip::TLV::kTLVType_Structure, dummyType));
        EXPECT_SUCCESS(pWriter->PutBoolean(chip::TLV::ContextTag(1), true));
        EXPECT_SUCCESS(pWriter->EndContainer(dummyType));
    }

    EXPECT_SUCCESS(attributeDataIBBuilder.EndOfAttributeDataIB());
    EXPECT_SUCCESS(attributeDataIBBuilder.GetError());

    EXPECT_SUCCESS(attributeDataIBsBuilder.EndOfAttributeDataIBs());
    EXPECT_SUCCESS(attributeDataIBsBuilder.GetError());
    // MoreChunkedMessages is emitted after the AttributeDataIBs, mirroring WriteClient::FinishMessage.
    EXPECT_SUCCESS(writeRequestBuilder.MoreChunkedMessages(true).EndOfWriteRequestMessage());
    EXPECT_SUCCESS(writeRequestBuilder.GetError());

    EXPECT_SUCCESS(writer.Finalize(&aPayload));
}

void TestWriteInteraction::GenerateWriteResponse(System::PacketBufferHandle & aPayload)
{
    System::PacketBufferTLVWriter writer;
    writer.Init(std::move(aPayload));

    WriteResponseMessage::Builder writeResponseBuilder;
    EXPECT_EQ(writeResponseBuilder.Init(&writer), CHIP_NO_ERROR);
    AttributeStatusIBs::Builder & attributeStatusesBuilder = writeResponseBuilder.CreateWriteResponses();
    EXPECT_EQ(attributeStatusesBuilder.GetError(), CHIP_NO_ERROR);
    AttributeStatusIB::Builder & attributeStatusIBBuilder = attributeStatusesBuilder.CreateAttributeStatus();
    EXPECT_EQ(attributeStatusIBBuilder.GetError(), CHIP_NO_ERROR);

    AttributePathIB::Builder & attributePathBuilder = attributeStatusIBBuilder.CreatePath();
    EXPECT_EQ(attributePathBuilder.GetError(), CHIP_NO_ERROR);
    EXPECT_EQ(attributePathBuilder.Node(1)
                  .Endpoint(2)
                  .Cluster(3)
                  .Attribute(4)
                  .ListIndex(DataModel::Nullable<ListIndex>())
                  .EndOfAttributePathIB(),
              CHIP_NO_ERROR);

    StatusIB::Builder & statusIBBuilder = attributeStatusIBBuilder.CreateErrorStatus();
    StatusIB statusIB;
    statusIB.mStatus = chip::Protocols::InteractionModel::Status::InvalidSubscription;
    EXPECT_EQ(statusIBBuilder.GetError(), CHIP_NO_ERROR);
    statusIBBuilder.EncodeStatusIB(statusIB);
    EXPECT_EQ(statusIBBuilder.GetError(), CHIP_NO_ERROR);

    EXPECT_SUCCESS(attributeStatusIBBuilder.EndOfAttributeStatusIB());
    EXPECT_EQ(attributeStatusIBBuilder.GetError(), CHIP_NO_ERROR);

    EXPECT_SUCCESS(attributeStatusesBuilder.EndOfAttributeStatuses());
    EXPECT_EQ(attributeStatusesBuilder.GetError(), CHIP_NO_ERROR);
    EXPECT_SUCCESS(writeResponseBuilder.EndOfWriteResponseMessage());
    EXPECT_EQ(writeResponseBuilder.GetError(), CHIP_NO_ERROR);

    EXPECT_EQ(writer.Finalize(&aPayload), CHIP_NO_ERROR);
}

TEST_F_FROM_FIXTURE(TestWriteInteraction, TestWriteClient)
{

    for (EncodingMethod encoding : { EncodingMethod::Standard, EncodingMethod::PreencodedTLV })
    {
        TestWriteClientCallback callback;
        app::WriteClient writeClient(&GetExchangeManager(), &callback, /* aTimedWriteTimeoutMs = */ NullOptional);

        System::PacketBufferHandle buf = System::PacketBufferHandle::New(System::PacketBuffer::kMaxSize);
        AddAttributeDataIB(writeClient, encoding);

        EXPECT_EQ(writeClient.SendWriteRequest(GetSessionBobToAlice()), CHIP_NO_ERROR);

        DrainAndServiceIO();

        GenerateWriteResponse(buf);

        EXPECT_EQ(writeClient.ProcessWriteResponseMessage(std::move(buf)), CHIP_NO_ERROR);

        writeClient.Close();

        Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
        EXPECT_EQ(rm->TestGetCountRetransTable(), 0);
    }
}

TEST_F_FROM_FIXTURE(TestWriteInteraction, TestWriteClientGroup)
{
    for (EncodingMethod encodingMethod : { EncodingMethod::Standard, EncodingMethod::PreencodedTLV })
    {
        TestWriteClientCallback callback;
        app::WriteClient writeClient(&GetExchangeManager(), &callback, /* aTimedWriteTimeoutMs = */ NullOptional);

        System::PacketBufferHandle buf = System::PacketBufferHandle::New(System::PacketBuffer::kMaxSize);
        AddAttributeDataIB(writeClient, encodingMethod);

        SessionHandle groupSession = GetSessionBobToFriends();
        EXPECT_TRUE(groupSession->IsGroupSession());

        EXPECT_EQ(writeClient.SendWriteRequest(groupSession), CHIP_NO_ERROR);

        DrainAndServiceIO();

        // The WriteClient should be shutdown once we SendWriteRequest for group.
        EXPECT_EQ(writeClient.mState, WriteClient::State::AwaitingDestruction);
    }
}

TEST_F(TestWriteInteraction, TestWriteHandler)
{
    using namespace Protocols::InteractionModel;

    constexpr bool allBooleans[] = { true, false };
    for (auto messageIsTimed : allBooleans)
    {
        for (auto transactionIsTimed : allBooleans)
        {

            app::WriteHandler writeHandler;

            System::PacketBufferHandle buf = System::PacketBufferHandle::New(System::PacketBuffer::kMaxSize);

            EXPECT_SUCCESS(writeHandler.Init(chip::app::InteractionModelEngine::GetInstance()->GetDataModelProvider(),
                                             chip::app::InteractionModelEngine::GetInstance()));

            GenerateWriteRequest(messageIsTimed, buf);

            TestExchangeDelegate delegate;
            Messaging::ExchangeContext * exchange = NewExchangeToBob(&delegate);

            Status status = writeHandler.OnWriteRequest(exchange, std::move(buf), transactionIsTimed);
            if (messageIsTimed == transactionIsTimed)
            {
                EXPECT_EQ(status, Status::Success);
            }
            else
            {
                EXPECT_EQ(status, Status::TimedRequestMismatch);
            }

            DrainAndServiceIO();

            Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
            EXPECT_EQ(rm->TestGetCountRetransTable(), 0);
        }
    }
}

TEST_F(TestWriteInteraction, TestWriteRoundtripWithClusterObjects)
{

    for (EncodingMethod encoding : { EncodingMethod::Standard, EncodingMethod::PreencodedTLV })
    {
        Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
        // Shouldn't have anything in the retransmit table when starting the test.
        EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

        TestWriteClientCallback callback;
        auto * engine = chip::app::InteractionModelEngine::GetInstance();
        EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()),
                  CHIP_NO_ERROR);

        app::WriteClient writeClient(engine->GetExchangeManager(), &callback, Optional<uint16_t>::Missing());

        System::PacketBufferHandle buf = System::PacketBufferHandle::New(System::PacketBuffer::kMaxSize);

        AttributePathParams attributePathParams;
        attributePathParams.mEndpointId  = kTestEndpointId;
        attributePathParams.mClusterId   = Clusters::UnitTesting::Id;
        attributePathParams.mAttributeId = Clusters::UnitTesting::Attributes::Boolean::Id;

        const uint8_t byteSpanData[]     = { 0xde, 0xad, 0xbe, 0xef };
        static const char charSpanData[] = "a simple test string";

        app::Clusters::UnitTesting::Structs::SimpleStruct::Type dataTx;
        dataTx.a = 12;
        dataTx.b = true;
        dataTx.d = chip::ByteSpan(byteSpanData);
        // Spec A.11.2 strings SHALL NOT include a terminating null character to mark the end of a string.
        dataTx.e = chip::Span<const char>(charSpanData, strlen(charSpanData));

        if (encoding == EncodingMethod::Standard)
        {
            EXPECT_EQ(writeClient.EncodeAttribute(attributePathParams, dataTx), CHIP_NO_ERROR);
        }
        else if (encoding == EncodingMethod::PreencodedTLV)
        {
            // Encode AttributeData into TLV
            uint8_t buffer[50];
            TLV::TLVWriter writer;
            writer.Init(buffer, sizeof(buffer));
            TLV::TLVType outerContainer;

            EXPECT_EQ(CHIP_NO_ERROR, writer.StartContainer(TLV::AnonymousTag(), TLV::kTLVType_Structure, outerContainer));
            EXPECT_EQ(CHIP_NO_ERROR, writer.Put(TLV::ContextTag(0), dataTx.a));
            EXPECT_EQ(CHIP_NO_ERROR, writer.PutBoolean(TLV::ContextTag(1), dataTx.b));
            EXPECT_EQ(CHIP_NO_ERROR, writer.Put(TLV::ContextTag(3), dataTx.d));
            EXPECT_EQ(CHIP_NO_ERROR, writer.PutString(TLV::ContextTag(4), dataTx.e));
            EXPECT_EQ(CHIP_NO_ERROR, writer.EndContainer(outerContainer));

            // Put Preencoded Data into AttributeDataIB
            TLV::TLVReader dataTxTLV;
            dataTxTLV.Init(buffer, writer.GetLengthWritten());
            EXPECT_SUCCESS(dataTxTLV.Next());
            ConcreteDataAttributePath path = ConcreteDataAttributePath(
                attributePathParams.mEndpointId, attributePathParams.mClusterId, attributePathParams.mAttributeId);
            EXPECT_EQ(writeClient.PutPreencodedAttribute(path, dataTxTLV), CHIP_NO_ERROR);
        }

        EXPECT_EQ(callback.mOnSuccessCalled, 0);

        EXPECT_EQ(writeClient.SendWriteRequest(GetSessionBobToAlice()), CHIP_NO_ERROR);

        DrainAndServiceIO();

        EXPECT_EQ(callback.mOnSuccessCalled, 1);

        {
            app::Clusters::UnitTesting::Structs::SimpleStruct::Type dataRx;
            TLV::TLVReader reader;
            reader.Init(chip::Testing::attributeDataTLV, chip::Testing::attributeDataTLVLen);
            EXPECT_SUCCESS(reader.Next());
            EXPECT_EQ(CHIP_NO_ERROR, DataModel::Decode(reader, dataRx));
            EXPECT_EQ(dataRx.a, dataTx.a);
            EXPECT_EQ(dataRx.b, dataTx.b);
            EXPECT_TRUE(dataRx.d.data_equal(dataTx.d));
            // Equals to dataRx.e.size() == dataTx.e.size() && memncmp(dataRx.e.data(), dataTx.e.data(), dataTx.e.size()) == 0
            EXPECT_TRUE(dataRx.e.data_equal(dataTx.e));
        }

        EXPECT_EQ(callback.mOnSuccessCalled, 1);
        EXPECT_EQ(callback.mOnErrorCalled, 0);
        EXPECT_EQ(callback.mOnDoneCalled, 1);

        // By now we should have closed all exchanges and sent all pending acks, so
        // there should be no queued-up things in the retransmit table.
        EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

        engine->Shutdown();
    }
}

TEST_F(TestWriteInteraction, TestWriteRoundtripWithClusterObjectsVersionMatch)
{

    Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
    // Shouldn't have anything in the retransmit table when starting the test.
    EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

    TestWriteClientCallback callback;
    auto * engine = chip::app::InteractionModelEngine::GetInstance();
    EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()), CHIP_NO_ERROR);

    app::WriteClient writeClient(engine->GetExchangeManager(), &callback, Optional<uint16_t>::Missing());

    System::PacketBufferHandle buf = System::PacketBufferHandle::New(System::PacketBuffer::kMaxSize);

    AttributePathParams attributePathParams;
    attributePathParams.mEndpointId  = kTestEndpointId;
    attributePathParams.mClusterId   = Clusters::UnitTesting::Id;
    attributePathParams.mAttributeId = Clusters::UnitTesting::Attributes::Boolean::Id;

    DataModel::Nullable<app::Clusters::UnitTesting::Structs::SimpleStruct::Type> dataTx;

    Optional<DataVersion> version(kAcceptedDataVersion);
    chip::Testing::SetVersionTo(kAcceptedDataVersion);

    EXPECT_EQ(writeClient.EncodeAttribute(attributePathParams, dataTx, version), CHIP_NO_ERROR);

    EXPECT_EQ(callback.mOnSuccessCalled, 0);

    EXPECT_EQ(writeClient.SendWriteRequest(GetSessionBobToAlice()), CHIP_NO_ERROR);

    DrainAndServiceIO();

    EXPECT_EQ(callback.mOnSuccessCalled, 1);
    EXPECT_EQ(callback.mOnErrorCalled, 0);
    EXPECT_EQ(callback.mOnDoneCalled, 1);
    EXPECT_EQ(callback.mStatus.mStatus, Protocols::InteractionModel::Status::Success);

    // By now we should have closed all exchanges and sent all pending acks, so
    // there should be no queued-up things in the retransmit table.
    EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

    engine->Shutdown();
}

TEST_F(TestWriteInteraction, TestWriteRoundtripWithClusterObjectsVersionMismatch)
{

    Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
    // Shouldn't have anything in the retransmit table when starting the test.
    EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

    TestWriteClientCallback callback;
    auto * engine = chip::app::InteractionModelEngine::GetInstance();
    EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()), CHIP_NO_ERROR);

    app::WriteClient writeClient(engine->GetExchangeManager(), &callback, Optional<uint16_t>::Missing());

    System::PacketBufferHandle buf = System::PacketBufferHandle::New(System::PacketBuffer::kMaxSize);

    AttributePathParams attributePathParams;
    attributePathParams.mEndpointId  = kTestEndpointId;
    attributePathParams.mClusterId   = Clusters::UnitTesting::Id;
    attributePathParams.mAttributeId = Clusters::UnitTesting::Attributes::Boolean::Id;

    app::Clusters::UnitTesting::Structs::SimpleStruct::Type dataTxValue;
    dataTxValue.a = 12;
    dataTxValue.b = true;
    DataModel::Nullable<app::Clusters::UnitTesting::Structs::SimpleStruct::Type> dataTx;
    dataTx.SetNonNull(dataTxValue);
    Optional<DataVersion> version(chip::Testing::kRejectedDataVersion);
    chip::Testing::SetVersionTo(kAcceptedDataVersion);
    static_assert(kAcceptedDataVersion != kRejectedDataVersion);

    EXPECT_EQ(writeClient.EncodeAttribute(attributePathParams, dataTx, version), CHIP_NO_ERROR);

    EXPECT_EQ(callback.mOnSuccessCalled, 0);

    EXPECT_EQ(writeClient.SendWriteRequest(GetSessionBobToAlice()), CHIP_NO_ERROR);

    DrainAndServiceIO();

    EXPECT_EQ(callback.mOnSuccessCalled, 1);
    EXPECT_EQ(callback.mOnErrorCalled, 0);
    EXPECT_EQ(callback.mOnDoneCalled, 1);
    EXPECT_EQ(callback.mStatus.mStatus, Protocols::InteractionModel::Status::DataVersionMismatch);

    // By now we should have closed all exchanges and sent all pending acks, so
    // there should be no queued-up things in the retransmit table.
    EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

    engine->Shutdown();
}

TEST_F(TestWriteInteraction, TestWriteRoundtrip)
{
    for (EncodingMethod encodingMethod : { EncodingMethod::Standard, EncodingMethod::PreencodedTLV })
    {
        Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
        // Shouldn't have anything in the retransmit table when starting the test.
        EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

        TestWriteClientCallback callback;
        auto * engine = chip::app::InteractionModelEngine::GetInstance();
        EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()),
                  CHIP_NO_ERROR);

        app::WriteClient writeClient(engine->GetExchangeManager(), &callback, Optional<uint16_t>::Missing());

        System::PacketBufferHandle buf = System::PacketBufferHandle::New(System::PacketBuffer::kMaxSize);
        AddAttributeDataIB(writeClient, encodingMethod);

        EXPECT_EQ(callback.mOnSuccessCalled, 0);
        EXPECT_EQ(callback.mOnErrorCalled, 0);
        EXPECT_EQ(callback.mOnDoneCalled, 0);

        EXPECT_EQ(writeClient.SendWriteRequest(GetSessionBobToAlice()), CHIP_NO_ERROR);

        DrainAndServiceIO();

        EXPECT_EQ(callback.mOnSuccessCalled, 1);
        EXPECT_EQ(callback.mOnErrorCalled, 0);
        EXPECT_EQ(callback.mOnDoneCalled, 1);
        // By now we should have closed all exchanges and sent all pending acks, so
        // there should be no queued-up things in the retransmit table.
        EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

        engine->Shutdown();
    }
}

TEST_F(TestWriteInteraction, TestWriteClientSuppressResponseFlow)
{
    for (EncodingMethod encodingMethod : { EncodingMethod::Standard, EncodingMethod::PreencodedTLV })
    {
        Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
        // Shouldn't have anything in the retransmit table when starting the test.
        EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

        TestWriteClientCallback callback;
        auto * engine = chip::app::InteractionModelEngine::GetInstance();
        EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()),
                  CHIP_NO_ERROR);

        app::WriteClient writeClient(engine->GetExchangeManager(), &callback, Optional<uint16_t>::Missing(),
                                     /* aSuppressResponse = */ true);

        AddAttributeDataIB(writeClient, encodingMethod);

        EXPECT_EQ(callback.mOnSuccessCalled, 0);
        EXPECT_EQ(callback.mOnErrorCalled, 0);
        EXPECT_EQ(callback.mOnDoneCalled, 0);

        EXPECT_EQ(writeClient.SendWriteRequest(GetSessionBobToAlice()), CHIP_NO_ERROR);

        DrainAndServiceIO();

        // Since aSuppressResponse is true, the server will receive the request and suppress the response.
        // Therefore, no response should be sent back to the client.
        EXPECT_EQ(callback.mOnSuccessCalled, 0);
        EXPECT_EQ(callback.mOnErrorCalled, 0);
        EXPECT_EQ(callback.mOnDoneCalled, 1);
        EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

        engine->Shutdown();
    }
}

TEST_F_FROM_FIXTURE(TestWriteInteraction, TestWriteClientSuppressResponseFlowWithInvalidAttribute)
{
    for (EncodingMethod encodingMethod : { EncodingMethod::Standard, EncodingMethod::PreencodedTLV })
    {
        Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
        // Shouldn't have anything in the retransmit table when starting the test.
        EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

        TestWriteClientCallback callback;
        auto * engine = chip::app::InteractionModelEngine::GetInstance();
        EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()),
                  CHIP_NO_ERROR);

        app::WriteClient writeClient(engine->GetExchangeManager(), &callback, Optional<uint16_t>::Missing(),
                                     /* aSuppressResponse */ true);

        AddInvalidAttributeDataIB(writeClient, encodingMethod);

        EXPECT_EQ(callback.mOnSuccessCalled, 0);
        EXPECT_EQ(callback.mOnErrorCalled, 0);
        EXPECT_EQ(callback.mOnDoneCalled, 0);

        GetLoopback().mSentMessageCount = 0;

        EXPECT_EQ(writeClient.SendWriteRequest(GetSessionBobToAlice()), CHIP_NO_ERROR);

        DrainAndServiceIO();

        // Since suppressResponse is true, the server will receive the request, process it, find the attribute is invalid,
        // but it will suppress any response, including a StatusResponse.
        // The client's OnDone should be called.
        EXPECT_EQ(callback.mOnSuccessCalled, 0);
        EXPECT_EQ(callback.mOnErrorCalled, 0);
        EXPECT_EQ(callback.mOnDoneCalled, 1);

        // The client sends 1 message (WriteRequest). The server receives it and sends 1 message back (MRP Ack).
        // No StatusResponse should be sent.
        EXPECT_EQ(GetLoopback().mSentMessageCount, 2u);

        EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

        engine->Shutdown();
    }
}

// This test creates a chunked write request, we drop the second write chunk message, then write handler receives unknown
// report message and sends out a status report with invalid action.
#if CONFIG_BUILD_FOR_HOST_UNIT_TEST
TEST_F_FROM_FIXTURE(TestWriteInteraction, TestWriteHandlerReceiveInvalidMessage)
{
    auto sessionHandle = GetSessionBobToAlice();

    app::AttributePathParams attributePath(2, 3, 4);

    Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
    // Shouldn't have anything in the retransmit table when starting the test.
    EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

    TestWriteClientCallback writeCallback;
    auto * engine = chip::app::InteractionModelEngine::GetInstance();
    EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()), CHIP_NO_ERROR);

    // Reserve all except the last 60 bytes, so that we make sure to chunk. it was empirically determined that with a list of 10
    // ByteSpan items, we will be able to fit 5/6 list items into the initial ReplaceAll list; thus triggering chunking.
    app::WriteClient writeClient(&GetExchangeManager(), &writeCallback, Optional<uint16_t>::Missing(),
                                 static_cast<uint16_t>(kMaxSecureSduLengthBytes - 60) /* reserved buffer size */);

    constexpr uint8_t kTestListLength = 10;
    ByteSpan list[kTestListLength];

    EXPECT_EQ(writeClient.EncodeAttribute(attributePath, app::DataModel::List<ByteSpan>(list, kTestListLength)), CHIP_NO_ERROR);

    EXPECT_TRUE(writeClient.IsWriteRequestChunked());

    GetLoopback().mSentMessageCount                 = 0;
    GetLoopback().mNumMessagesToDrop                = 1;
    GetLoopback().mNumMessagesToAllowBeforeDropping = 2;
    EXPECT_EQ(writeClient.SendWriteRequest(sessionHandle), CHIP_NO_ERROR);
    DrainAndServiceIO();

    EXPECT_EQ(InteractionModelEngine::GetInstance()->GetNumActiveWriteHandlers(), 1u);
    EXPECT_EQ(GetLoopback().mSentMessageCount, 3u);
    EXPECT_EQ(GetLoopback().mDroppedMessageCount, 1u);

    System::PacketBufferHandle msgBuf = System::PacketBufferHandle::New(kMaxSecureSduLengthBytes);
    EXPECT_FALSE(msgBuf.IsNull());
    System::PacketBufferTLVWriter writer;
    writer.Init(std::move(msgBuf));

    ReportDataMessage::Builder response;
    EXPECT_SUCCESS(response.Init(&writer));
    EXPECT_EQ(writer.Finalize(&msgBuf), CHIP_NO_ERROR);

    PayloadHeader payloadHeader;
    payloadHeader.SetExchangeID(0);
    payloadHeader.SetMessageType(chip::Protocols::InteractionModel::MsgType::ReportData);

    auto * writeHandler = InteractionModelEngine::GetInstance()->ActiveWriteHandlerAt(0);

    rm->ClearRetransTable(writeClient.mExchangeCtx.Get());
    rm->ClearRetransTable(writeHandler->mExchangeCtx.Get());
    GetLoopback().mSentMessageCount  = 0;
    GetLoopback().mNumMessagesToDrop = 0;
    EXPECT_EQ(writeHandler->OnMessageReceived(writeHandler->mExchangeCtx.Get(), payloadHeader, std::move(msgBuf)),
              CHIP_ERROR_INVALID_MESSAGE_TYPE);
    DrainAndServiceIO();

    EXPECT_EQ(writeCallback.mLastErrorReason.mStatus, Protocols::InteractionModel::Status::InvalidAction);
    EXPECT_EQ(InteractionModelEngine::GetInstance()->GetNumActiveWriteHandlers(), 0u);
    engine->Shutdown();
    ExpireSessionAliceToBob();
    ExpireSessionBobToAlice();
    EXPECT_SUCCESS(CreateSessionAliceToBob());
    EXPECT_SUCCESS(CreateSessionBobToAlice());
}

// This test is to create Chunked write requests, we drop the message since the 3rd message, then remove fabrics for client and
// handler, the corresponding client and handler would be released as well.
TEST_F(TestWriteInteraction, TestWriteHandlerInvalidateFabric)
{
    auto sessionHandle = GetSessionBobToAlice();

    app::AttributePathParams attributePath(2, 3, 4);

    Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
    // Shouldn't have anything in the retransmit table when starting the test.
    EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

    TestWriteClientCallback writeCallback;
    auto * engine = chip::app::InteractionModelEngine::GetInstance();
    EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()), CHIP_NO_ERROR);

    // Reserve all except the last 60 bytes, so that we make sure to chunk. it was empirically determined that with a list of 10
    // ByteSpan items, we will be able to fit 5/6 list items into the initial ReplaceAll list; thus triggering chunking.
    app::WriteClient writeClient(&GetExchangeManager(), &writeCallback, Optional<uint16_t>::Missing(),
                                 static_cast<uint16_t>(kMaxSecureSduLengthBytes - 60) /* reserved buffer size */);

    constexpr uint8_t kTestListLength = 10;
    ByteSpan list[kTestListLength];

    EXPECT_EQ(writeClient.EncodeAttribute(attributePath, app::DataModel::List<ByteSpan>(list, kTestListLength)), CHIP_NO_ERROR);

    EXPECT_TRUE(writeClient.IsWriteRequestChunked());

    GetLoopback().mDroppedMessageCount              = 0;
    GetLoopback().mSentMessageCount                 = 0;
    GetLoopback().mNumMessagesToDrop                = 1;
    GetLoopback().mNumMessagesToAllowBeforeDropping = 2;
    EXPECT_EQ(writeClient.SendWriteRequest(sessionHandle), CHIP_NO_ERROR);
    DrainAndServiceIO();

    EXPECT_EQ(InteractionModelEngine::GetInstance()->GetNumActiveWriteHandlers(), 1u);
    EXPECT_EQ(GetLoopback().mSentMessageCount, 3u);
    EXPECT_EQ(GetLoopback().mDroppedMessageCount, 1u);

    EXPECT_SUCCESS(GetFabricTable().Delete(GetAliceFabricIndex()));
    EXPECT_EQ(InteractionModelEngine::GetInstance()->GetNumActiveWriteHandlers(), 0u);
    engine->Shutdown();
    ExpireSessionAliceToBob();
    ExpireSessionBobToAlice();
    EXPECT_SUCCESS(CreateAliceFabric());
    EXPECT_SUCCESS(CreateSessionAliceToBob());
    EXPECT_SUCCESS(CreateSessionBobToAlice());
}

// A first WriteRequest chunk that sets SuppressResponse=true together with MoreChunkedMessages=true keeps the
// WriteHandler allocated waiting for the next chunk, yet nothing is sent on the exchange (SuppressResponse skips
// the WriteResponse and WillSendMessage() is never called). The exchange layer then closes the exchange underneath
// the handler, which would be left allocated with no exchange and never reclaimed. Because the handler pool is
// bounded (CHIP_IM_MAX_NUM_WRITE_HANDLER), repeated such requests would exhaust it and further WriteRequests would
// be answered with Busy.
//
// Expected behavior: such a first chunk must not leave a handler allocated once the exchange has been serviced, so
// the active-handler count returns to 0 and the pool never fills.
TEST_F_FROM_FIXTURE(TestWriteInteraction, TestSuppressedChunkedWriteDoesNotLeakHandler)
{
    using namespace Protocols::InteractionModel;

    auto * engine = InteractionModelEngine::GetInstance();
    EXPECT_SUCCESS(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()));

    // One delegate outlives every exchange created below (through Shutdown/session teardown), so no exchange
    // can reference a destroyed delegate.
    TestExchangeDelegate delegate;

    // Send more than the pool size to confirm each such request is released rather than accumulating.
    for (uint32_t i = 0; i < CHIP_IM_MAX_NUM_WRITE_HANDLER + 1; ++i)
    {
        System::PacketBufferHandle buf = System::PacketBufferHandle::New(System::PacketBuffer::kMaxSize);
        ASSERT_FALSE(buf.IsNull());
        GenerateSuppressResponseChunkedWriteRequest(buf);

        Messaging::ExchangeContext * exchange = NewExchangeToBob(&delegate);
        ASSERT_NE(exchange, nullptr);

        // SuppressResponse => the client does not expect a response back.
        EXPECT_SUCCESS(exchange->SendMessage(MsgType::WriteRequest, std::move(buf), Messaging::SendMessageFlags::kNone));
        DrainAndServiceIO();

        EXPECT_EQ(engine->GetNumActiveWriteHandlers(), 0u);
    }

    engine->Shutdown();
    ExpireSessionAliceToBob();
    ExpireSessionBobToAlice();
    EXPECT_SUCCESS(CreateSessionAliceToBob());
    EXPECT_SUCCESS(CreateSessionBobToAlice());
}

// The sending side is guarded symmetrically: a WriteClient must not produce a chunked write that suppresses the
// response (SuppressResponse SHALL be false when MoreChunkedMessages is true). When the payload is large enough to
// require chunking, encoding fails rather than emitting the invalid combination.
TEST_F_FROM_FIXTURE(TestWriteInteraction, TestWriteClientRejectsSuppressedChunkedWrite)
{
    TestWriteClientCallback writeCallback;
    auto * engine = InteractionModelEngine::GetInstance();
    EXPECT_SUCCESS(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()));

    // Reserve most of the buffer so the list is forced to chunk (same technique as the chunked-write tests above).
    app::WriteClient writeClient(&GetExchangeManager(), &writeCallback, Optional<uint16_t>::Missing(),
                                 static_cast<uint16_t>(kMaxSecureSduLengthBytes - 60) /* reserved buffer size */);
    writeClient.mSuppressResponse = true;

    app::AttributePathParams attributePath(2, 3, 4);
    constexpr uint8_t kTestListLength = 10;
    ByteSpan list[kTestListLength];

    // Encoding needs a second chunk, which is rejected because the response is suppressed.
    EXPECT_EQ(writeClient.EncodeAttribute(attributePath, app::DataModel::List<ByteSpan>(list, kTestListLength)),
              CHIP_ERROR_INVALID_MESSAGE_TYPE);

    engine->Shutdown();
}

#endif

// This test sends an invalid (because there is no application payload at all)
// Write Request message and makes sure that a correct Status Response is
// received.
TEST_F_FROM_FIXTURE(TestWriteInteraction, TestWriteHandlerReceiveEmptyWriteRequest)
{
    Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
    // Shouldn't have anything in the retransmit table when starting the test.
    EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

    TestWriteClientCallback writeCallback;
    auto * engine = chip::app::InteractionModelEngine::GetInstance();
    EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()), CHIP_NO_ERROR);

    GetLoopback().mDroppedMessageCount = 0;
    GetLoopback().mSentMessageCount    = 0;
    GetLoopback().mNumMessagesToDrop   = 0;

    // Just send an empty message claiming to be a write request.
    System::PacketBufferHandle emptyMessage = System::PacketBufferHandle::New(Crypto::CHIP_CRYPTO_AEAD_MIC_LENGTH_BYTES);

    TestExchangeDelegate delegate;
    delegate.mLastStatusParsedSuccessfully = false;

    auto exchange = NewExchangeToAlice(&delegate);
    EXPECT_NE(exchange, nullptr);

    EXPECT_EQ(exchange->SendMessage(Protocols::InteractionModel::MsgType::WriteRequest, std::move(emptyMessage),
                                    Messaging::SendMessageFlags::kExpectResponse),
              CHIP_NO_ERROR);

    DrainAndServiceIO();

    EXPECT_EQ(InteractionModelEngine::GetInstance()->GetNumActiveWriteHandlers(), 0u);
    EXPECT_EQ(GetLoopback().mSentMessageCount, 3u); // Request, response, ack
    EXPECT_EQ(GetLoopback().mDroppedMessageCount, 0u);

    EXPECT_TRUE(delegate.mLastStatusParsedSuccessfully);
    EXPECT_EQ(delegate.mLastStatus, Protocols::InteractionModel::Status::InvalidAction);

    engine->Shutdown();
    ExpireSessionAliceToBob();
    ExpireSessionBobToAlice();
    EXPECT_SUCCESS(CreateSessionAliceToBob());
    EXPECT_SUCCESS(CreateSessionBobToAlice());
}

// Write Client sends a write request, receives an unexpected message type, sends a status response to that.
TEST_F_FROM_FIXTURE(TestWriteInteraction, TestWriteInvalidMessage1)
{

    Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
    // Shouldn't have anything in the retransmit table when starting the test.
    EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

    TestWriteClientCallback callback;
    auto * engine = chip::app::InteractionModelEngine::GetInstance();
    EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()), CHIP_NO_ERROR);

    app::WriteClient writeClient(engine->GetExchangeManager(), &callback, Optional<uint16_t>::Missing());

    System::PacketBufferHandle buf = System::PacketBufferHandle::New(System::PacketBuffer::kMaxSize);
    AddAttributeDataIB(writeClient);

    EXPECT_EQ(callback.mOnSuccessCalled, 0);
    EXPECT_EQ(callback.mOnErrorCalled, 0);
    EXPECT_EQ(callback.mOnDoneCalled, 0);

    GetLoopback().mSentMessageCount                 = 0;
    GetLoopback().mNumMessagesToDrop                = 1;
    GetLoopback().mNumMessagesToAllowBeforeDropping = 1;
    GetLoopback().mDroppedMessageCount              = 0;
    EXPECT_EQ(writeClient.SendWriteRequest(GetSessionBobToAlice()), CHIP_NO_ERROR);
    DrainAndServiceIO();

    EXPECT_EQ(GetLoopback().mSentMessageCount, 2u);
    EXPECT_EQ(GetLoopback().mDroppedMessageCount, 1u);

    System::PacketBufferHandle msgBuf = System::PacketBufferHandle::New(kMaxSecureSduLengthBytes);
    EXPECT_FALSE(msgBuf.IsNull());
    System::PacketBufferTLVWriter writer;
    writer.Init(std::move(msgBuf));
    ReportDataMessage::Builder response;
    EXPECT_SUCCESS(response.Init(&writer));
    EXPECT_EQ(writer.Finalize(&msgBuf), CHIP_NO_ERROR);
    PayloadHeader payloadHeader;
    payloadHeader.SetExchangeID(0);
    payloadHeader.SetMessageType(chip::Protocols::InteractionModel::MsgType::ReportData);

    // Since we are dropping packets, things are not getting acked.  Set up
    // our MRP state to look like what it would have looked like if the
    // packet had not gotten dropped.
    PretendWeGotReplyFromServer(*this, writeClient.mExchangeCtx.Get());

    GetLoopback().mSentMessageCount                 = 0;
    GetLoopback().mNumMessagesToDrop                = 0;
    GetLoopback().mNumMessagesToAllowBeforeDropping = 0;
    GetLoopback().mDroppedMessageCount              = 0;
    EXPECT_EQ(writeClient.OnMessageReceived(writeClient.mExchangeCtx.Get(), payloadHeader, std::move(msgBuf)),
              CHIP_ERROR_INVALID_MESSAGE_TYPE);
    DrainAndServiceIO();
    EXPECT_EQ(callback.mError, CHIP_ERROR_INVALID_MESSAGE_TYPE);

    EXPECT_EQ(callback.mOnSuccessCalled, 0);
    EXPECT_EQ(callback.mOnErrorCalled, 1);
    EXPECT_EQ(callback.mOnDoneCalled, 1);

    // TODO: Check that the server gets the right status.
    // Client sents status report with invalid action, server's exchange has been closed, so all it sends is an MRP Ack
    EXPECT_EQ(GetLoopback().mSentMessageCount, 2u);

    engine->Shutdown();
    ExpireSessionAliceToBob();
    ExpireSessionBobToAlice();
    EXPECT_SUCCESS(CreateSessionAliceToBob());
    EXPECT_SUCCESS(CreateSessionBobToAlice());
}

// Write Client sends a write request, receives a malformed write response message, sends a Status Report.
TEST_F_FROM_FIXTURE(TestWriteInteraction, TestWriteInvalidMessage2)
{

    Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
    // Shouldn't have anything in the retransmit table when starting the test.
    EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

    TestWriteClientCallback callback;
    auto * engine = chip::app::InteractionModelEngine::GetInstance();
    EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()), CHIP_NO_ERROR);

    app::WriteClient writeClient(engine->GetExchangeManager(), &callback, Optional<uint16_t>::Missing());

    System::PacketBufferHandle buf = System::PacketBufferHandle::New(System::PacketBuffer::kMaxSize);
    AddAttributeDataIB(writeClient);

    EXPECT_EQ(callback.mOnSuccessCalled, 0);
    EXPECT_EQ(callback.mOnErrorCalled, 0);
    EXPECT_EQ(callback.mOnDoneCalled, 0);

    GetLoopback().mSentMessageCount                 = 0;
    GetLoopback().mNumMessagesToDrop                = 1;
    GetLoopback().mNumMessagesToAllowBeforeDropping = 1;
    GetLoopback().mDroppedMessageCount              = 0;
    EXPECT_EQ(writeClient.SendWriteRequest(GetSessionBobToAlice()), CHIP_NO_ERROR);
    DrainAndServiceIO();

    EXPECT_EQ(GetLoopback().mSentMessageCount, 2u);
    EXPECT_EQ(GetLoopback().mDroppedMessageCount, 1u);

    System::PacketBufferHandle msgBuf = System::PacketBufferHandle::New(kMaxSecureSduLengthBytes);
    EXPECT_FALSE(msgBuf.IsNull());
    System::PacketBufferTLVWriter writer;
    writer.Init(std::move(msgBuf));
    WriteResponseMessage::Builder response;
    EXPECT_SUCCESS(response.Init(&writer));
    EXPECT_EQ(writer.Finalize(&msgBuf), CHIP_NO_ERROR);
    PayloadHeader payloadHeader;
    payloadHeader.SetExchangeID(0);
    payloadHeader.SetMessageType(chip::Protocols::InteractionModel::MsgType::WriteResponse);

    // Since we are dropping packets, things are not getting acked.  Set up
    // our MRP state to look like what it would have looked like if the
    // packet had not gotten dropped.
    PretendWeGotReplyFromServer(*this, writeClient.mExchangeCtx.Get());

    GetLoopback().mSentMessageCount                 = 0;
    GetLoopback().mNumMessagesToDrop                = 0;
    GetLoopback().mNumMessagesToAllowBeforeDropping = 0;
    GetLoopback().mDroppedMessageCount              = 0;
    EXPECT_EQ(writeClient.OnMessageReceived(writeClient.mExchangeCtx.Get(), payloadHeader, std::move(msgBuf)),
              CHIP_ERROR_END_OF_TLV);
    DrainAndServiceIO();
    EXPECT_EQ(callback.mError, CHIP_ERROR_END_OF_TLV);

    EXPECT_EQ(callback.mOnSuccessCalled, 0);
    EXPECT_EQ(callback.mOnErrorCalled, 1);
    EXPECT_EQ(callback.mOnDoneCalled, 1);

    // Client sents status report with invalid action, server's exchange has been closed, so all it sends is an MRP Ack
    EXPECT_EQ(GetLoopback().mSentMessageCount, 2u);

    engine->Shutdown();
    ExpireSessionAliceToBob();
    ExpireSessionBobToAlice();
    EXPECT_SUCCESS(CreateSessionAliceToBob());
    EXPECT_SUCCESS(CreateSessionBobToAlice());
}

// Write Client sends a write request, receives a malformed status response message.
TEST_F_FROM_FIXTURE(TestWriteInteraction, TestWriteInvalidMessage3)
{

    Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
    // Shouldn't have anything in the retransmit table when starting the test.
    EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

    TestWriteClientCallback callback;
    auto * engine = chip::app::InteractionModelEngine::GetInstance();
    EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()), CHIP_NO_ERROR);

    app::WriteClient writeClient(engine->GetExchangeManager(), &callback, Optional<uint16_t>::Missing());

    System::PacketBufferHandle buf = System::PacketBufferHandle::New(System::PacketBuffer::kMaxSize);
    AddAttributeDataIB(writeClient);

    EXPECT_EQ(callback.mOnSuccessCalled, 0);
    EXPECT_EQ(callback.mOnErrorCalled, 0);
    EXPECT_EQ(callback.mOnDoneCalled, 0);

    GetLoopback().mSentMessageCount                 = 0;
    GetLoopback().mNumMessagesToDrop                = 1;
    GetLoopback().mNumMessagesToAllowBeforeDropping = 1;
    GetLoopback().mDroppedMessageCount              = 0;
    EXPECT_EQ(writeClient.SendWriteRequest(GetSessionBobToAlice()), CHIP_NO_ERROR);
    DrainAndServiceIO();

    EXPECT_EQ(GetLoopback().mSentMessageCount, 2u);
    EXPECT_EQ(GetLoopback().mDroppedMessageCount, 1u);

    System::PacketBufferHandle msgBuf = System::PacketBufferHandle::New(kMaxSecureSduLengthBytes);
    EXPECT_FALSE(msgBuf.IsNull());
    System::PacketBufferTLVWriter writer;
    writer.Init(std::move(msgBuf));
    StatusResponseMessage::Builder response;
    EXPECT_SUCCESS(response.Init(&writer));
    EXPECT_EQ(writer.Finalize(&msgBuf), CHIP_NO_ERROR);
    PayloadHeader payloadHeader;
    payloadHeader.SetExchangeID(0);
    payloadHeader.SetMessageType(chip::Protocols::InteractionModel::MsgType::StatusResponse);

    // Since we are dropping packets, things are not getting acked.  Set up
    // our MRP state to look like what it would have looked like if the
    // packet had not gotten dropped.
    PretendWeGotReplyFromServer(*this, writeClient.mExchangeCtx.Get());

    GetLoopback().mSentMessageCount                 = 0;
    GetLoopback().mNumMessagesToDrop                = 0;
    GetLoopback().mNumMessagesToAllowBeforeDropping = 0;
    GetLoopback().mDroppedMessageCount              = 0;
    EXPECT_EQ(writeClient.OnMessageReceived(writeClient.mExchangeCtx.Get(), payloadHeader, std::move(msgBuf)),
              CHIP_ERROR_END_OF_TLV);
    DrainAndServiceIO();
    EXPECT_EQ(callback.mError, CHIP_ERROR_END_OF_TLV);

    EXPECT_EQ(callback.mOnSuccessCalled, 0);
    EXPECT_EQ(callback.mOnErrorCalled, 1);
    EXPECT_EQ(callback.mOnDoneCalled, 1);

    // TODO: Check that the server gets the right status
    // Client sents status report with invalid action, server's exchange has been closed, so all it sends is an MRP ack.
    EXPECT_EQ(GetLoopback().mSentMessageCount, 2u);

    engine->Shutdown();
    ExpireSessionAliceToBob();
    ExpireSessionBobToAlice();
    EXPECT_SUCCESS(CreateSessionAliceToBob());
    EXPECT_SUCCESS(CreateSessionBobToAlice());
}

// Write Client sends a write request, receives a busy status response message.
TEST_F_FROM_FIXTURE(TestWriteInteraction, TestWriteInvalidMessage4)
{

    Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
    // Shouldn't have anything in the retransmit table when starting the test.
    EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

    TestWriteClientCallback callback;
    auto * engine = chip::app::InteractionModelEngine::GetInstance();
    EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()), CHIP_NO_ERROR);

    app::WriteClient writeClient(engine->GetExchangeManager(), &callback, Optional<uint16_t>::Missing());

    System::PacketBufferHandle buf = System::PacketBufferHandle::New(System::PacketBuffer::kMaxSize);
    AddAttributeDataIB(writeClient);

    EXPECT_EQ(callback.mOnSuccessCalled, 0);
    EXPECT_EQ(callback.mOnErrorCalled, 0);
    EXPECT_EQ(callback.mOnDoneCalled, 0);

    GetLoopback().mSentMessageCount                 = 0;
    GetLoopback().mNumMessagesToDrop                = 1;
    GetLoopback().mNumMessagesToAllowBeforeDropping = 1;
    GetLoopback().mDroppedMessageCount              = 0;
    EXPECT_EQ(writeClient.SendWriteRequest(GetSessionBobToAlice()), CHIP_NO_ERROR);
    DrainAndServiceIO();

    EXPECT_EQ(GetLoopback().mSentMessageCount, 2u);
    EXPECT_EQ(GetLoopback().mDroppedMessageCount, 1u);

    System::PacketBufferHandle msgBuf = System::PacketBufferHandle::New(kMaxSecureSduLengthBytes);
    EXPECT_FALSE(msgBuf.IsNull());
    System::PacketBufferTLVWriter writer;
    writer.Init(std::move(msgBuf));
    StatusResponseMessage::Builder response;
    EXPECT_SUCCESS(response.Init(&writer));
    response.Status(Protocols::InteractionModel::Status::Busy);
    EXPECT_EQ(writer.Finalize(&msgBuf), CHIP_NO_ERROR);
    PayloadHeader payloadHeader;
    payloadHeader.SetExchangeID(0);
    payloadHeader.SetMessageType(chip::Protocols::InteractionModel::MsgType::StatusResponse);

    // Since we are dropping packets, things are not getting acked.  Set up
    // our MRP state to look like what it would have looked like if the
    // packet had not gotten dropped.
    PretendWeGotReplyFromServer(*this, writeClient.mExchangeCtx.Get());

    GetLoopback().mSentMessageCount                 = 0;
    GetLoopback().mNumMessagesToDrop                = 0;
    GetLoopback().mNumMessagesToAllowBeforeDropping = 0;
    GetLoopback().mDroppedMessageCount              = 0;
    EXPECT_EQ(writeClient.OnMessageReceived(writeClient.mExchangeCtx.Get(), payloadHeader, std::move(msgBuf)),
              CHIP_IM_GLOBAL_STATUS(Busy));
    DrainAndServiceIO();
    EXPECT_EQ(callback.mError, CHIP_IM_GLOBAL_STATUS(Busy));

    EXPECT_EQ(callback.mOnSuccessCalled, 0);
    EXPECT_EQ(callback.mOnErrorCalled, 1);
    EXPECT_EQ(callback.mOnDoneCalled, 1);

    // TODO: Check that the server gets the right status..
    // Client sents status report with invalid action, server's exchange has been closed, so it just sends an MRP ack.
    EXPECT_EQ(GetLoopback().mSentMessageCount, 2u);

    engine->Shutdown();
    ExpireSessionAliceToBob();
    ExpireSessionBobToAlice();
    EXPECT_SUCCESS(CreateSessionAliceToBob());
    EXPECT_SUCCESS(CreateSessionBobToAlice());
}

// Write Client sends a chunked write request, receives an unexpected status response message (Busy) after sending the first chunk.
TEST_F_FROM_FIXTURE(TestWriteInteraction, TestWriteInvalidMessage5)
{
    Messaging::ReliableMessageMgr * rm = GetExchangeManager().GetReliableMessageMgr();
    // Shouldn't have anything in the retransmit table when starting the test.
    EXPECT_EQ(rm->TestGetCountRetransTable(), 0);

    TestWriteClientCallback callback;
    auto * engine = chip::app::InteractionModelEngine::GetInstance();
    EXPECT_EQ(engine->Init(&GetExchangeManager(), &GetFabricTable(), app::reporting::GetDefaultReportScheduler()), CHIP_NO_ERROR);

    // Reserve buffer to trigger chunking
    app::WriteClient writeClient(engine->GetExchangeManager(), &callback, Optional<uint16_t>::Missing(),
                                 static_cast<uint16_t>(kMaxSecureSduLengthBytes - 60) /* reserved buffer size */);

    app::AttributePathParams attributePath(2, 3, 4);
    constexpr uint8_t kTestListLength = 10;
    ByteSpan list[kTestListLength];

    EXPECT_EQ(writeClient.EncodeAttribute(attributePath, app::DataModel::List<ByteSpan>(list, kTestListLength)), CHIP_NO_ERROR);
    EXPECT_TRUE(writeClient.IsWriteRequestChunked());

    EXPECT_EQ(callback.mOnSuccessCalled, 0);
    EXPECT_EQ(callback.mOnErrorCalled, 0);
    EXPECT_EQ(callback.mOnDoneCalled, 0);

    GetLoopback().mSentMessageCount                 = 0;
    GetLoopback().mNumMessagesToDrop                = 1;
    GetLoopback().mNumMessagesToAllowBeforeDropping = 1;
    GetLoopback().mDroppedMessageCount              = 0;
    EXPECT_EQ(writeClient.SendWriteRequest(GetSessionBobToAlice()), CHIP_NO_ERROR);
    DrainAndServiceIO();

    EXPECT_EQ(GetLoopback().mSentMessageCount, 2u);
    EXPECT_EQ(GetLoopback().mDroppedMessageCount, 1u);

    System::PacketBufferHandle msgBuf = System::PacketBufferHandle::New(kMaxSecureSduLengthBytes);
    EXPECT_FALSE(msgBuf.IsNull());
    System::PacketBufferTLVWriter writer;
    writer.Init(std::move(msgBuf));
    StatusResponseMessage::Builder response;
    EXPECT_SUCCESS(response.Init(&writer));
    response.Status(Protocols::InteractionModel::Status::Busy);
    EXPECT_EQ(writer.Finalize(&msgBuf), CHIP_NO_ERROR);
    PayloadHeader payloadHeader;
    payloadHeader.SetExchangeID(0);
    payloadHeader.SetMessageType(chip::Protocols::InteractionModel::MsgType::StatusResponse);

    // Since we are dropping packets, things are not getting acked.  Set up
    // our MRP state to look like what it would have looked like if the
    // packet had not gotten dropped.
    PretendWeGotReplyFromServer(*this, writeClient.mExchangeCtx.Get());

    GetLoopback().mSentMessageCount                 = 0;
    GetLoopback().mNumMessagesToDrop                = 0;
    GetLoopback().mNumMessagesToAllowBeforeDropping = 0;
    GetLoopback().mDroppedMessageCount              = 0;
    EXPECT_EQ(writeClient.OnMessageReceived(writeClient.mExchangeCtx.Get(), payloadHeader, std::move(msgBuf)),
              CHIP_IM_GLOBAL_STATUS(Busy));
    DrainAndServiceIO();
    EXPECT_EQ(callback.mError, CHIP_IM_GLOBAL_STATUS(Busy));

    EXPECT_EQ(callback.mOnSuccessCalled, 0);
    EXPECT_EQ(callback.mOnErrorCalled, 1);
    EXPECT_EQ(callback.mOnDoneCalled, 1);

    engine->Shutdown();
    ExpireSessionAliceToBob();
    ExpireSessionBobToAlice();
    EXPECT_SUCCESS(CreateSessionAliceToBob());
    EXPECT_SUCCESS(CreateSessionBobToAlice());
}

} // namespace app
} // namespace chip