/*
 *
 *    Copyright (c) 2021-2024 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 <app/InteractionModelTimeout.h>
#include <controller/AutoCommissioner.h>
#include <controller/CHIPDeviceController.h>
#include <credentials/CHIPCert.h>
#include <lib/support/SafeInt.h>

#include <cstring>
#include <type_traits>

namespace chip {
namespace Controller {

using namespace chip::app::Clusters;
using namespace chip::Crypto;
using chip::app::DataModel::MakeNullable;
using chip::app::DataModel::NullNullable;

AutoCommissioner::AutoCommissioner()
{
    TEMPORARY_RETURN_IGNORED SetCommissioningParameters(CommissioningParameters());
}

AutoCommissioner::~AutoCommissioner() {}

void AutoCommissioner::SetOperationalCredentialsDelegate(OperationalCredentialsDelegate * operationalCredentialsDelegate)
{
    mOperationalCredentialsDelegate = operationalCredentialsDelegate;
}

CHIP_ERROR AutoCommissioner::VerifyICDRegistrationInfo(const CommissioningParameters & params)
{
    ChipLogProgress(Controller, "Checking ICD registration parameters");
    if (!params.GetICDSymmetricKey().HasValue())
    {
        ChipLogError(Controller, "Missing ICD symmetric key!");
        return CHIP_ERROR_INVALID_ARGUMENT;
    }
    if (params.GetICDSymmetricKey().Value().size() != sizeof(mICDSymmetricKey))
    {
        ChipLogError(Controller, "Invalid ICD symmetric key length!");
        return CHIP_ERROR_INVALID_ARGUMENT;
    }
    if (!params.GetICDCheckInNodeId().HasValue())
    {
        ChipLogError(Controller, "Missing ICD check-in node id!");
        return CHIP_ERROR_INVALID_ARGUMENT;
    }
    if (!params.GetICDMonitoredSubject().HasValue())
    {
        ChipLogError(Controller, "Missing ICD monitored subject!");
        return CHIP_ERROR_INVALID_ARGUMENT;
    }
    if (!params.GetICDClientType().HasValue())
    {
        ChipLogError(Controller, "Missing ICD Client Type!");
        return CHIP_ERROR_INVALID_ARGUMENT;
    }
    return CHIP_NO_ERROR;
}

CHIP_ERROR AutoCommissioner::SetCommissioningParameters(const CommissioningParameters & params)
{
    // Our logic below assumes that we can modify mParams without affecting params.
    VerifyOrReturnError(&params != &mParams, CHIP_NO_ERROR);

    // Copy the whole struct (scalars and pointers), but clear any members that might point to
    // external buffers. For those members we have to copy the data over into our own buffers below.
    // Note that all of the copy operations use memmove() instead of memcpy(), because the caller
    // may be passing a modified shallow copy of our CommissioningParmeters, i.e. where various spans
    // already point into the buffers we're copying into, and memcpy() with overlapping buffers is UB.
    mParams = params;
    mParams.ClearExternalBufferDependentValues();

    if (params.GetThreadOperationalDataset().HasValue())
    {
        ByteSpan dataset = params.GetThreadOperationalDataset().Value();
        if (dataset.size() > CommissioningParameters::kMaxThreadDatasetLen)
        {
            ChipLogError(Controller, "Thread operational data set is too large");
            return CHIP_ERROR_INVALID_ARGUMENT;
        }
        memmove(mThreadOperationalDataset, dataset.data(), dataset.size());
        ChipLogProgress(Controller, "Setting thread operational dataset from parameters");
        mParams.SetThreadOperationalDataset(ByteSpan(mThreadOperationalDataset, dataset.size()));
    }

    if (params.GetWiFiCredentials().HasValue())
    {
        WiFiCredentials creds = params.GetWiFiCredentials().Value();
        if (creds.ssid.size() > CommissioningParameters::kMaxSsidLen ||
            creds.credentials.size() > CommissioningParameters::kMaxCredentialsLen)
        {
            ChipLogError(Controller, "Wifi credentials are too large");
            return CHIP_ERROR_INVALID_ARGUMENT;
        }
        memmove(mSsid, creds.ssid.data(), creds.ssid.size());
        memmove(mCredentials, creds.credentials.data(), creds.credentials.size());
        ChipLogProgress(Controller, "Setting wifi credentials from parameters");
        mParams.SetWiFiCredentials(
            WiFiCredentials(ByteSpan(mSsid, creds.ssid.size()), ByteSpan(mCredentials, creds.credentials.size())));
    }

    if (params.GetCountryCode().HasValue())
    {
        auto code = params.GetCountryCode().Value();
        MutableCharSpan copiedCode(mCountryCode);
        if (CopyCharSpanToMutableCharSpan(code, copiedCode) == CHIP_NO_ERROR)
        {
            mParams.SetCountryCode(copiedCode);
        }
        else
        {
            ChipLogError(Controller, "Country code is too large: %u", static_cast<unsigned>(code.size()));
            return CHIP_ERROR_INVALID_ARGUMENT;
        }
    }

    // If the AttestationNonce is passed in, using that else using a random one..
    if (params.GetAttestationNonce().HasValue())
    {
        ChipLogProgress(Controller, "Setting attestation nonce from parameters");
        VerifyOrReturnError(params.GetAttestationNonce().Value().size() == sizeof(mAttestationNonce), CHIP_ERROR_INVALID_ARGUMENT);
        memmove(mAttestationNonce, params.GetAttestationNonce().Value().data(), params.GetAttestationNonce().Value().size());
    }
    else
    {
        ChipLogProgress(Controller, "Setting attestation nonce to random value");
        TEMPORARY_RETURN_IGNORED Crypto::DRBG_get_bytes(mAttestationNonce, sizeof(mAttestationNonce));
    }
    mParams.SetAttestationNonce(ByteSpan(mAttestationNonce, sizeof(mAttestationNonce)));

    if (params.GetCSRNonce().HasValue())
    {
        ChipLogProgress(Controller, "Setting CSR nonce from parameters");
        VerifyOrReturnError(params.GetCSRNonce().Value().size() == sizeof(mCSRNonce), CHIP_ERROR_INVALID_ARGUMENT);
        memmove(mCSRNonce, params.GetCSRNonce().Value().data(), params.GetCSRNonce().Value().size());
    }
    else
    {
        ChipLogProgress(Controller, "Setting CSR nonce to random value");
        TEMPORARY_RETURN_IGNORED Crypto::DRBG_get_bytes(mCSRNonce, sizeof(mCSRNonce));
    }
    mParams.SetCSRNonce(ByteSpan(mCSRNonce, sizeof(mCSRNonce)));

    if (params.GetDSTOffsets().HasValue())
    {
        ChipLogProgress(Controller, "Setting DST offsets from parameters");
        size_t size = std::min(params.GetDSTOffsets().Value().size(), kMaxSupportedDstStructs);
        for (size_t i = 0; i < size; ++i)
        {
            mDstOffsetsBuf[i] = params.GetDSTOffsets().Value()[i];
        }
        auto list = app::DataModel::List<app::Clusters::TimeSynchronization::Structs::DSTOffsetStruct::Type>(mDstOffsetsBuf, size);
        mParams.SetDSTOffsets(list);
    }
    if (params.GetTimeZone().HasValue())
    {
        ChipLogProgress(Controller, "Setting Time Zone from parameters");
        size_t size = std::min(params.GetTimeZone().Value().size(), kMaxSupportedTimeZones);
        for (size_t i = 0; i < size; ++i)
        {
            mTimeZoneBuf[i] = params.GetTimeZone().Value()[i];
            if (params.GetTimeZone().Value()[i].name.HasValue() &&
                params.GetTimeZone().Value()[i].name.Value().size() <= kMaxTimeZoneNameLen)
            {
                auto span = MutableCharSpan(mTimeZoneNames[i], kMaxTimeZoneNameLen);
                // The buffer backing "span" is statically allocated and is of size kMaxSupportedTimeZones, so this should never
                // fail.
                TEMPORARY_RETURN_IGNORED CopyCharSpanToMutableCharSpan(params.GetTimeZone().Value()[i].name.Value(), span);
                mTimeZoneBuf[i].name.SetValue(span);
            }
            else
            {
                mTimeZoneBuf[i].name.ClearValue();
            }
        }
        auto list = app::DataModel::List<app::Clusters::TimeSynchronization::Structs::TimeZoneStruct::Type>(mTimeZoneBuf, size);
        mParams.SetTimeZone(list);
    }
    if (params.GetDefaultNTP().HasValue())
    {
        ChipLogProgress(Controller, "Setting Default NTP from parameters");
        // This parameter is an optional nullable, so we need to go two levels deep here.
        if (!params.GetDefaultNTP().Value().IsNull() && params.GetDefaultNTP().Value().Value().size() <= kMaxDefaultNtpSize)
        {
            // The buffer backing "span" is statically allocated and is of size kMaxDefaultNtpSize.
            auto span = MutableCharSpan(mDefaultNtp, kMaxDefaultNtpSize);
            TEMPORARY_RETURN_IGNORED CopyCharSpanToMutableCharSpan(params.GetDefaultNTP().Value().Value(), span);
            auto default_ntp = MakeNullable(CharSpan(mDefaultNtp, params.GetDefaultNTP().Value().Value().size()));
            mParams.SetDefaultNTP(default_ntp);
        }
    }

    if (params.GetICDRegistrationStrategy() != ICDRegistrationStrategy::kIgnore && params.GetICDSymmetricKey().HasValue())
    {
        ReturnErrorOnFailure(VerifyICDRegistrationInfo(params));

        // The values must be valid now.
        memmove(mICDSymmetricKey, params.GetICDSymmetricKey().Value().data(), params.GetICDSymmetricKey().Value().size());
        mParams.SetICDSymmetricKey(ByteSpan(mICDSymmetricKey));
        mParams.SetICDCheckInNodeId(params.GetICDCheckInNodeId().Value());
        mParams.SetICDMonitoredSubject(params.GetICDMonitoredSubject().Value());
        mParams.SetICDClientType(params.GetICDClientType().Value());
    }

    auto extraReadPaths = params.GetExtraReadPaths();
    if (extraReadPaths.size() > 0)
    {
        using ReadPath = std::remove_pointer_t<decltype(extraReadPaths.data())>;
        static_assert(std::is_trivially_copyable_v<ReadPath>, "can't use memmove / memcpy, not trivially copyable");

        if (mExtraReadPaths.AllocatedSize() == extraReadPaths.size())
        {
            memmove(mExtraReadPaths.Get(), extraReadPaths.data(), extraReadPaths.size() * sizeof(ReadPath));
        }
        else
        {
            // We can't reallocate mExtraReadPaths yet as this would free the old buffer,
            // and the caller might be passing a sub-span of the old paths.
            decltype(mExtraReadPaths) oldReadPaths(std::move(mExtraReadPaths));
            VerifyOrReturnError(mExtraReadPaths.Alloc(extraReadPaths.size()), CHIP_ERROR_NO_MEMORY);
            memcpy(mExtraReadPaths.Get(), extraReadPaths.data(), extraReadPaths.size() * sizeof(ReadPath));
        }

        mParams.SetExtraReadPaths(mExtraReadPaths.Span());
    }
    else
    {
        mExtraReadPaths.Free();
    }

    return CHIP_NO_ERROR;
}

const CommissioningParameters & AutoCommissioner::GetCommissioningParameters() const
{
    return mParams;
}

CommissioningStage AutoCommissioner::GetNextCommissioningStage(CommissioningStage currentStage, CHIP_ERROR & lastErr)
{
    auto nextStage = GetNextCommissioningStageInternal(currentStage, lastErr);
    if (lastErr == CHIP_NO_ERROR)
    {
        ChipLogProgress(Controller, "Commissioning stage next step: '%s' -> '%s'", StageToString(currentStage),
                        StageToString(nextStage));
    }
    else
    {
        ChipLogProgress(Controller, "Going from commissioning step '%s' with lastErr = '%s' -> '%s'", StageToString(currentStage),
                        lastErr.AsString(), StageToString(nextStage));
    }
    return nextStage;
}

CommissioningStage AutoCommissioner::GetNextCommissioningStageNetworkSetup(CommissioningStage currentStage, CHIP_ERROR & lastErr)
{
    if (!IsSomeNetworkSupported())
    {
        ChipLogError(Controller, "Network setup is needed, but commissionee does not support any network types we know about");
        lastErr = CHIP_ERROR_INCORRECT_STATE;
        return CommissioningStage::kCleanup;
    }

    enum class NetworkType
    {
        kWiFi,
        kThread,
    };

    NetworkType networkToUse;
    if (TryingSecondaryNetwork())
    {
        // Try secondary network interface.
        networkToUse =
            mDeviceCommissioningInfo.network.wifi.endpoint == kRootEndpointId ? NetworkType::kThread : NetworkType::kWiFi;
    }
    else if (IsSecondaryNetworkSupported())
    {
        // Try primary network interface.
        TryPrimaryNetwork();
        networkToUse =
            mDeviceCommissioningInfo.network.wifi.endpoint == kRootEndpointId ? NetworkType::kWiFi : NetworkType::kThread;
    }
    else if (mParams.GetWiFiCredentials().HasValue() && mDeviceCommissioningInfo.network.wifi.endpoint != kInvalidEndpointId)
    {
        networkToUse = NetworkType::kWiFi;
    }
    else if (mParams.GetThreadOperationalDataset().HasValue() &&
             mDeviceCommissioningInfo.network.thread.endpoint != kInvalidEndpointId)
    {
        networkToUse = NetworkType::kThread;
    }
    else
    {
        // If we have ended up here, then the commissionee does not support trying two different
        // network technologies.  If it did, then either we would have credentials for one of them
        // and take one of those branches, or we would not have credentials for either one and
        // IsSecondaryNetworkSupported() would have tested true.
        //
        // Also, since we got here, we don't (yet) have credentials for the one network technology
        // the commissionee supports. Go ahead and just try to use that one network technology,
        // which should be the primary network (on the root endpoint).
        //
        // Note that we don't call TryPrimaryNetwork() here, because that's only used when there
        // will be a secondary network to try.  Which in this case there isn't.
        networkToUse =
            mDeviceCommissioningInfo.network.wifi.endpoint == kRootEndpointId ? NetworkType::kWiFi : NetworkType::kThread;
    }

    if (networkToUse == NetworkType::kWiFi)
    {
        if (mParams.GetWiFiCredentials().HasValue())
        {
            // Just go ahead and set that up.
            return CommissioningStage::kWiFiNetworkSetup;
        }

        // We need credentials but don't have them.  We need to ask for those.
        return CommissioningStage::kRequestWiFiCredentials;
    }

    // networkToUse must be kThread here.
    if (mParams.GetThreadOperationalDataset().HasValue())
    {
        // Just go ahead and set that up.
        return CommissioningStage::kThreadNetworkSetup;
    }

    // We need credentials but don't have them.  We need to ask for those.
    return CommissioningStage::kRequestThreadCredentials;
}

CommissioningStage AutoCommissioner::GetNextCommissioningStageInternal(CommissioningStage currentStage, CHIP_ERROR & lastErr)
{
    if (mStopCommissioning)
    {
        return CommissioningStage::kCleanup;
    }
    if (lastErr != CHIP_NO_ERROR)
    {
        return CommissioningStage::kCleanup;
    }

    switch (currentStage)
    {
    case CommissioningStage::kSecurePairing:
        return CommissioningStage::kReadCommissioningInfo;
    case CommissioningStage::kReadCommissioningInfo:
        if (mDeviceCommissioningInfo.general.breadcrumb > 0)
        {
            // If the breadcrumb is 0, the failsafe was disarmed.
            // We failed on network setup or later, the node failsafe has not been re-armed and the breadcrumb has not been reset.
            // Per the spec, we restart from after adding the NOC.
            return GetNextCommissioningStage(CommissioningStage::kSendNOC, lastErr);
        }
        return CommissioningStage::kArmFailsafe;
    case CommissioningStage::kArmFailsafe:
        return CommissioningStage::kConfigRegulatory;
    case CommissioningStage::kConfigRegulatory:
        return CommissioningStage::kConfigureTCAcknowledgments;
    case CommissioningStage::kConfigureTCAcknowledgments:
        if (mDeviceCommissioningInfo.requiresUTC)
        {
            return CommissioningStage::kConfigureUTCTime;
        }
        else
        {
            // Time cluster is not supported, move right to DA
            return CommissioningStage::kSendPAICertificateRequest;
        }
    case CommissioningStage::kConfigureUTCTime:
        if (mDeviceCommissioningInfo.requiresTimeZone && mParams.GetTimeZone().HasValue())
        {
            return kConfigureTimeZone;
        }
        else
        {
            return GetNextCommissioningStageInternal(CommissioningStage::kConfigureTimeZone, lastErr);
        }
    case CommissioningStage::kConfigureTimeZone:
        if (mNeedsDST && mParams.GetDSTOffsets().HasValue())
        {
            return CommissioningStage::kConfigureDSTOffset;
        }
        else
        {
            return GetNextCommissioningStageInternal(CommissioningStage::kConfigureDSTOffset, lastErr);
        }
    case CommissioningStage::kConfigureDSTOffset:
        if (mDeviceCommissioningInfo.requiresDefaultNTP && mParams.GetDefaultNTP().HasValue())
        {
            return CommissioningStage::kConfigureDefaultNTP;
        }
        else
        {
            return GetNextCommissioningStageInternal(CommissioningStage::kConfigureDefaultNTP, lastErr);
        }
    case CommissioningStage::kConfigureDefaultNTP:
        return CommissioningStage::kSendPAICertificateRequest;
    case CommissioningStage::kSendPAICertificateRequest:
        return CommissioningStage::kSendDACCertificateRequest;
    case CommissioningStage::kSendDACCertificateRequest:
        return CommissioningStage::kSendAttestationRequest;
    case CommissioningStage::kSendAttestationRequest:
        return CommissioningStage::kAttestationVerification;
    case CommissioningStage::kAttestationVerification:
        return CommissioningStage::kAttestationRevocationCheck;
    case CommissioningStage::kAttestationRevocationCheck:
#if CHIP_DEVICE_CONFIG_ENABLE_JOINT_FABRIC
        if (mParams.GetUseJCM().ValueOr(false))
        {
            return CommissioningStage::kJCMTrustVerification;
        }
#endif // CHIP_DEVICE_CONFIG_ENABLE_JOINT_FABRIC
        return CommissioningStage::kSendOpCertSigningRequest;
    case CommissioningStage::kJCMTrustVerification:
        return CommissioningStage::kSendOpCertSigningRequest;
    case CommissioningStage::kSendOpCertSigningRequest:
        return CommissioningStage::kValidateCSR;
    case CommissioningStage::kValidateCSR:
        return CommissioningStage::kGenerateNOCChain;
    case CommissioningStage::kGenerateNOCChain:
        return CommissioningStage::kSendTrustedRootCert;
    case CommissioningStage::kSendTrustedRootCert:
        return CommissioningStage::kSendNOC;
    case CommissioningStage::kSendNOC:
        if (mDeviceCommissioningInfo.requiresTrustedTimeSource && mParams.GetTrustedTimeSource().HasValue())
        {
            return CommissioningStage::kConfigureTrustedTimeSource;
        }
        else
        {
            return GetNextCommissioningStageInternal(CommissioningStage::kConfigureTrustedTimeSource, lastErr);
        }
    case CommissioningStage::kConfigureTrustedTimeSource:
        if (mNeedIcdRegistration)
        {
            if (mParams.GetICDCheckInNodeId().HasValue() && mParams.GetICDMonitoredSubject().HasValue() &&
                mParams.GetICDSymmetricKey().HasValue())
            {
                return CommissioningStage::kICDRegistration;
            }
            return CommissioningStage::kICDGetRegistrationInfo;
        }
        return GetNextCommissioningStageInternal(CommissioningStage::kICDRegistration, lastErr);
    case CommissioningStage::kICDGetRegistrationInfo:
        return CommissioningStage::kICDRegistration;
    case CommissioningStage::kICDRegistration:
        // TODO(cecille): device attestation casues operational cert provisioning to happen, This should be a separate stage.
        // For thread and wifi, this should go to network setup then enable. For on-network we can skip right to finding the
        // operational network because the provisioning of certificates will trigger the device to start operational advertising.
        if (mNeedsNetworkSetup)
        {
            // if there is a WiFi or a Thread endpoint, then perform scan
            if (IsScanNeeded())
            {
                // Perform Scan (kScanNetworks) and collect credentials (kNeedsNetworkCreds) right before configuring network.
                // This order of steps allows the workflow to return to collect credentials again if network enablement fails.

                // TODO: This is broken when we have multiple network commissioning endpoints
                // We always end up doing the scan on endpoint 0, even if we have disabled that
                // endpoint and are trying to use the secondary network commissioning endpoint.
                // We should probably have separate stages for "scan Thread" and "scan Wi-Fi", which
                // would allow GetEndpoint() to do the right thing.  The IsScanNeeded() check should
                // also be changed to check the actual endpoint we are going to try to commission
                // here, not just "all the endpoints".
                //
                // See https://github.com/project-chip/connectedhomeip/issues/40755
                return CommissioningStage::kScanNetworks;
            }
            ChipLogProgress(Controller, "No NetworkScan enabled or WiFi/Thread endpoint not specified, skipping ScanNetworks");

            return GetNextCommissioningStageNetworkSetup(currentStage, lastErr);
        }
        else
        {
            SetCASEFailsafeTimerIfNeeded();
            if (mParams.GetSkipCommissioningComplete().ValueOr(false))
            {
                return CommissioningStage::kCleanup;
            }
            return CommissioningStage::kEvictPreviousCaseSessions;
        }
    case CommissioningStage::kScanNetworks:
    case CommissioningStage::kRequestWiFiCredentials:
    case CommissioningStage::kRequestThreadCredentials:
        return CommissioningStage::kNeedsNetworkCreds;
    case CommissioningStage::kNeedsNetworkCreds:
        return GetNextCommissioningStageNetworkSetup(currentStage, lastErr);
    case CommissioningStage::kWiFiNetworkSetup:
        return CommissioningStage::kFailsafeBeforeWiFiEnable;
    case CommissioningStage::kThreadNetworkSetup:
        return CommissioningStage::kFailsafeBeforeThreadEnable;
    case CommissioningStage::kFailsafeBeforeWiFiEnable:
        return CommissioningStage::kWiFiNetworkEnable;
    case CommissioningStage::kFailsafeBeforeThreadEnable:
        return CommissioningStage::kThreadNetworkEnable;
    case CommissioningStage::kWiFiNetworkEnable:
        if (mParams.GetSkipCommissioningComplete().ValueOr(false))
        {
            SetCASEFailsafeTimerIfNeeded();
            return CommissioningStage::kCleanup;
        }
        else
        {
            SetCASEFailsafeTimerIfNeeded();
            return CommissioningStage::kEvictPreviousCaseSessions;
        }
    case CommissioningStage::kThreadNetworkEnable:
        SetCASEFailsafeTimerIfNeeded();
        if (mParams.GetSkipCommissioningComplete().ValueOr(false))
        {
            return CommissioningStage::kCleanup;
        }
        return CommissioningStage::kEvictPreviousCaseSessions;
    case CommissioningStage::kEvictPreviousCaseSessions:
#if CHIP_DEVICE_CONFIG_ENABLE_NFC_BASED_COMMISSIONING
    {
        // If there is no secure session, means commissioning has been continued after the unpowered phase was completed
        // In such case, move on setup the CASE session over operational network
        if (!mCommissioneeDeviceProxy->GetSecureSession().HasValue())
        {
            return CommissioningStage::kFindOperationalForStayActive;
        }

        // If the transport is NFC, move to unpowered phase complete to end the first phase of commissioning
        auto transportType =
            mCommissioneeDeviceProxy->GetSecureSession().Value()->AsSecureSession()->GetPeerAddress().GetTransportType();
        return (transportType == Transport::Type::kNfc && mDeviceCommissioningInfo.general.isCommissioningWithoutPower)
            ? CommissioningStage::kUnpoweredPhaseComplete
            : CommissioningStage::kFindOperationalForStayActive;
    }
#else
        return CommissioningStage::kFindOperationalForStayActive;
#endif
    case CommissioningStage::kPrimaryOperationalNetworkFailed:
        if (mDeviceCommissioningInfo.network.wifi.endpoint == kRootEndpointId)
        {
            return CommissioningStage::kRemoveWiFiNetworkConfig;
        }
        else
        {
            return CommissioningStage::kRemoveThreadNetworkConfig;
        }
    case CommissioningStage::kRemoveWiFiNetworkConfig:
    case CommissioningStage::kRemoveThreadNetworkConfig:
        return GetNextCommissioningStageNetworkSetup(currentStage, lastErr);
    case CommissioningStage::kFindOperationalForStayActive:
        return CommissioningStage::kICDSendStayActive;
    case CommissioningStage::kICDSendStayActive:
        return CommissioningStage::kFindOperationalForCommissioningComplete;
    case CommissioningStage::kFindOperationalForCommissioningComplete:
        return CommissioningStage::kSendComplete;
    case CommissioningStage::kSendComplete:
        return CommissioningStage::kCleanup;
#if CHIP_DEVICE_CONFIG_ENABLE_NFC_BASED_COMMISSIONING
    case CommissioningStage::kUnpoweredPhaseComplete:
        return CommissioningStage::kCleanup; // End commissioning (phase 1)
#endif

    // Neither of these have a next stage so return kError;
    case CommissioningStage::kCleanup:
    case CommissioningStage::kError:
        return CommissioningStage::kError;
    }
    return CommissioningStage::kError;
}

// No specific actions to take when an error happens since this command can fail and commissioning can still succeed.
static void OnFailsafeFailureForCASE(void * context, CHIP_ERROR error)
{
    ChipLogProgress(Controller, "ExtendFailsafe received failure response: %" CHIP_ERROR_FORMAT, error.Format());
}

// No specific actions to take upon success.
static void
OnExtendFailsafeSuccessForCASE(void * context,
                               const app::Clusters::GeneralCommissioning::Commands::ArmFailSafeResponse::DecodableType & data)
{
    ChipLogProgress(Controller, "ExtendFailsafe received ArmFailSafe response errorCode=%u", to_underlying(data.errorCode));
}

void AutoCommissioner::SetCASEFailsafeTimerIfNeeded()
{
    // if there is a final fail-safe timer configured then, send it
    if (mParams.GetCASEFailsafeTimerSeconds().HasValue() && mCommissioneeDeviceProxy != nullptr)
    {
        // send the command via the PASE session (mCommissioneeDeviceProxy) since the CASE portion of commissioning
        // might be done by a different service (ex. PASE is done by a phone app and CASE is done by a Hub).
        // Also, we want the CASE failsafe timer to apply for the time it takes the Hub to perform operational discovery,
        // CASE establishment, and receipt of the commissioning complete command.
        // We know that the mCommissioneeDeviceProxy is still valid at this point since it gets cleared during cleanup
        // and SetCASEFailsafeTimerIfNeeded is always called before that stage.
        //
        // A false return from ExtendArmFailSafe is fine; we don't want to make
        // the fail-safe shorter here.
        mCommissioner->ExtendArmFailSafe(mCommissioneeDeviceProxy, mCommissioner->GetCommissioningStage(),
                                         mParams.GetCASEFailsafeTimerSeconds().Value(),
                                         GetCommandTimeout(mCommissioneeDeviceProxy, CommissioningStage::kArmFailsafe),
                                         OnExtendFailsafeSuccessForCASE, OnFailsafeFailureForCASE);
    }
}

EndpointId AutoCommissioner::GetEndpoint(const CommissioningStage & stage) const
{
    switch (stage)
    {
    case CommissioningStage::kRequestWiFiCredentials:
    case CommissioningStage::kWiFiNetworkSetup:
    case CommissioningStage::kWiFiNetworkEnable:
        return mDeviceCommissioningInfo.network.wifi.endpoint;
    case CommissioningStage::kRequestThreadCredentials:
    case CommissioningStage::kThreadNetworkSetup:
    case CommissioningStage::kThreadNetworkEnable:
        return mDeviceCommissioningInfo.network.thread.endpoint;
    case CommissioningStage::kRemoveWiFiNetworkConfig:
    case CommissioningStage::kRemoveThreadNetworkConfig:
        return kRootEndpointId;
    default:
        return kRootEndpointId;
    }
}

CHIP_ERROR AutoCommissioner::StartCommissioning(DeviceCommissioner * commissioner, CommissioneeDeviceProxy * proxy)
{
    if (commissioner == nullptr)
    {
        ChipLogError(Controller, "Invalid DeviceCommissioner");
        return CHIP_ERROR_INVALID_ARGUMENT;
    }

    // Proxy is expected to have a valid secure session before starting to commission. However, in case of continuing
    // commissioning post unpowered phase, allow proceeding if the stage is evict secure CASE sessions
    if (proxy == nullptr ||
        (!proxy->GetSecureSession().HasValue()
#if CHIP_DEVICE_CONFIG_ENABLE_NFC_BASED_COMMISSIONING
         && commissioner->GetCommissioningStage() != CommissioningStage::kEvictPreviousCaseSessions
#endif
         ))
    {
        ChipLogError(Controller, "Device proxy secure session error");
        return CHIP_ERROR_INVALID_ARGUMENT;
    }
    mStopCommissioning       = false;
    mCommissioner            = commissioner;
    mCommissioneeDeviceProxy = proxy;

    // When commissioning is started after unpowered phase, there will be no secure session since the CASE session first needs to be
    // setup over operational network. Hence assume transport is UDP in such case.
    auto transportType = Transport::Type::kUdp;
    if (mCommissioneeDeviceProxy->GetSecureSession().HasValue())
    {
        transportType =
            mCommissioneeDeviceProxy->GetSecureSession().Value()->AsSecureSession()->GetPeerAddress().GetTransportType();
    }

    mNeedsNetworkSetup = (transportType == Transport::Type::kBle);
#if CHIP_DEVICE_CONFIG_ENABLE_NFC_BASED_COMMISSIONING
    mNeedsNetworkSetup = mNeedsNetworkSetup || (transportType == Transport::Type::kNfc);
#endif
#if CHIP_DEVICE_CONFIG_ENABLE_WIFIPAF
    mNeedsNetworkSetup = mNeedsNetworkSetup || (transportType == Transport::Type::kWiFiPAF);
#endif
    CHIP_ERROR err               = CHIP_NO_ERROR;
    CommissioningStage nextStage = GetNextCommissioningStage(commissioner->GetCommissioningStage(), err);

    mCommissioner->PerformCommissioningStep(mCommissioneeDeviceProxy, nextStage, mParams, this, GetEndpoint(nextStage),
                                            GetCommandTimeout(mCommissioneeDeviceProxy, nextStage));
    return CHIP_NO_ERROR;
}

Optional<System::Clock::Timeout> AutoCommissioner::GetCommandTimeout(DeviceProxy * device, CommissioningStage stage) const
{
    // Network clusters can indicate the time required to connect, so if we are
    // connecting, use that time as our "how long it takes to process server
    // side" time.  Otherwise pick a time that should be enough for the command
    // processing: 7s for slow steps that can involve crypto, the default IM
    // timeout otherwise.
    // TODO: is this a reasonable estimate for the slow-crypto cases?
    constexpr System::Clock::Timeout kSlowCryptoProcessingTime = System::Clock::Seconds16(7);

    System::Clock::Timeout timeout;
    switch (stage)
    {
    case CommissioningStage::kWiFiNetworkEnable:
        ChipLogProgress(Controller, "Setting wifi connection time min = %u",
                        mDeviceCommissioningInfo.network.wifi.minConnectionTime);
        timeout = System::Clock::Seconds16(mDeviceCommissioningInfo.network.wifi.minConnectionTime);
        break;
    case CommissioningStage::kThreadNetworkEnable:
        timeout = System::Clock::Seconds16(mDeviceCommissioningInfo.network.thread.minConnectionTime);
        break;
    case CommissioningStage::kScanNetworks:
        // We're not sure which sort of scan we will do, so just use the larger
        // of the timeouts we might have.  Note that anything we select here is
        // still clamped to be at least kMinimumCommissioningStepTimeout below.
        timeout = System::Clock::Seconds16(
            std::max(mDeviceCommissioningInfo.network.wifi.maxScanTime, mDeviceCommissioningInfo.network.thread.maxScanTime));
        break;
    case CommissioningStage::kSendNOC:
    case CommissioningStage::kSendOpCertSigningRequest:
        timeout = kSlowCryptoProcessingTime;
        break;
    default:
        timeout = app::kExpectedIMProcessingTime;
        break;
    }

    // Adjust the timeout for our session transport latency, if we have access
    // to a session.
    auto sessionHandle = device->GetSecureSession();
    if (sessionHandle.HasValue())
    {
        timeout = sessionHandle.Value()->ComputeRoundTripTimeout(timeout, true /*isFirstMessageOnExchange*/);
    }

    // Enforce the spec minimal timeout.  Maybe this enforcement should live in
    // the DeviceCommissioner?
    if (timeout < kMinimumCommissioningStepTimeout)
    {
        timeout = kMinimumCommissioningStepTimeout;
    }

    return MakeOptional(timeout);
}

CHIP_ERROR AutoCommissioner::NOCChainGenerated(ByteSpan noc, ByteSpan icac, ByteSpan rcac, IdentityProtectionKeySpan ipk,
                                               NodeId adminSubject)
{
    // Reuse ICA Cert buffer for temporary store Root Cert.
    MutableByteSpan rootCert = MutableByteSpan(mICACertBuffer);
    ReturnErrorOnFailure(Credentials::ConvertX509CertToChipCert(rcac, rootCert));
    mParams.SetRootCert(rootCert);

    MutableByteSpan noCert = MutableByteSpan(mNOCertBuffer);
    ReturnErrorOnFailure(Credentials::ConvertX509CertToChipCert(noc, noCert));
    mParams.SetNoc(noCert);

    CommissioningStage nextStage = CommissioningStage::kSendTrustedRootCert;
    mCommissioner->PerformCommissioningStep(mCommissioneeDeviceProxy, nextStage, mParams, this, 0,
                                            GetCommandTimeout(mCommissioneeDeviceProxy, nextStage));

    // Trusted root cert has been sent, so we can re-use the icac buffer for the icac.
    if (!icac.empty())
    {
        MutableByteSpan icaCert = MutableByteSpan(mICACertBuffer);
        ReturnErrorOnFailure(Credentials::ConvertX509CertToChipCert(icac, icaCert));
        mParams.SetIcac(icaCert);
    }
    else
    {
        mParams.SetIcac(ByteSpan());
    }

    mParams.SetIpk(ipk);
    mParams.SetAdminSubject(adminSubject);

    return CHIP_NO_ERROR;
}

void AutoCommissioner::CleanupCommissioning()
{
    ResetNetworkAttemptType();
    mPAI.Free();
    mDAC.Free();
    mCommissioneeDeviceProxy = nullptr;
    mOperationalDeviceProxy  = OperationalDeviceProxy();
    mDeviceCommissioningInfo = ReadCommissioningInfo();
    mNeedsDST                = false;
}

CHIP_ERROR AutoCommissioner::CommissioningStepFinished(CHIP_ERROR err, CommissioningDelegate::CommissioningReport report)
{
    CompletionStatus completionStatus;
    completionStatus.err = err;
    if (err != CHIP_NO_ERROR)
    {
        ChipLogError(Controller, "Error on commissioning step '%s': '%s'", StageToString(report.stageCompleted), err.AsString());
        completionStatus.failedStage = MakeOptional(report.stageCompleted);
        if (report.Is<AttestationErrorInfo>())
        {
            completionStatus.attestationResult = MakeOptional(report.Get<AttestationErrorInfo>().attestationResult);
            if ((report.Get<AttestationErrorInfo>().attestationResult ==
                 Credentials::AttestationVerificationResult::kDacProductIdMismatch) ||
                (report.Get<AttestationErrorInfo>().attestationResult ==
                 Credentials::AttestationVerificationResult::kDacVendorIdMismatch))
            {
                ChipLogError(Controller,
                             "Failed device attestation. Device vendor and/or product ID do not match the IDs expected. "
                             "Verify DAC certificate chain and certification declaration to ensure spec rules followed.");
            }

            if (report.stageCompleted == CommissioningStage::kAttestationVerification)
            {
                ChipLogError(Controller, "Failed verifying attestation information. Now checking DAC chain revoked status.");
                // don't error out until we check for DAC chain revocation status
                err = CHIP_NO_ERROR;
            }
        }
        else if (report.Is<CommissioningErrorInfo>())
        {
            completionStatus.commissioningError = MakeOptional(report.Get<CommissioningErrorInfo>().commissioningError);
        }
        else if (report.Is<NetworkCommissioningStatusInfo>())
        {
            // This report type is used when an error happens in either NetworkConfig or ConnectNetwork commands
            completionStatus.networkCommissioningStatus =
                MakeOptional(report.Get<NetworkCommissioningStatusInfo>().networkCommissioningStatus);

            // If we are configured to scan networks, then don't error out.
            // Instead, allow the app to try another network.
            //
            // TODO: This doesn't actually work, because in order to provide credentials someone
            // had to SetWiFiCredentials() or SetThreadOperationalDataset() on our params, so
            // IsScanNeeded() will no longer test true for that network technology.
            if (IsScanNeeded())
            {
                if (completionStatus.err == CHIP_NO_ERROR)
                {
                    completionStatus.err = err;
                }
                err = CHIP_NO_ERROR;
                // Walk back the completed stage to kScanNetworks.
                // This will allow the app to try another network.
                report.stageCompleted = CommissioningStage::kScanNetworks;
            }
        }

        auto isNetworkFailureStage = [](CommissioningStage stage) {
            // If we were somewhere between network setup and and trying to finish up commissioning,
            // treat that as a network failure stage; trying the secondary network might work
            // better.
            if (stage >= kWiFiNetworkSetup && stage <= kICDSendStayActive)
            {
                return true;
            }

            // If we were trying to request credentials and failed (because our delegate does not
            // implement that functionality, for example), treat that as a network failure stage and
            // try the other network type.
            if (stage == kRequestThreadCredentials || stage == kRequestWiFiCredentials || stage == kNeedsNetworkCreds)
            {
                return true;
            }

            return false;
        };

        if (err != CHIP_NO_ERROR && TryingPrimaryNetwork() && completionStatus.failedStage.HasValue() &&
            isNetworkFailureStage(completionStatus.failedStage.Value()))
        {
            // Primary network failed, disable primary network interface and try secondary network interface.
            TrySecondaryNetwork();
            err                   = CHIP_NO_ERROR;
            report.stageCompleted = CommissioningStage::kPrimaryOperationalNetworkFailed;
        }
    }
    else
    {
        ChipLogProgress(Controller, "Successfully finished commissioning step '%s'", StageToString(report.stageCompleted));
        switch (report.stageCompleted)
        {
        case CommissioningStage::kReadCommissioningInfo: {
            mDeviceCommissioningInfo = report.Get<ReadCommissioningInfo>();

            if (!mParams.GetFailsafeTimerSeconds().HasValue() && mDeviceCommissioningInfo.general.recommendedFailsafe > 0)
            {
                mParams.SetFailsafeTimerSeconds(mDeviceCommissioningInfo.general.recommendedFailsafe);
            }
            mParams.SetRemoteVendorId(mDeviceCommissioningInfo.basic.vendorId)
                .SetRemoteProductId(mDeviceCommissioningInfo.basic.productId)
                .SetDefaultRegulatoryLocation(mDeviceCommissioningInfo.general.currentRegulatoryLocation)
                .SetLocationCapability(mDeviceCommissioningInfo.general.locationCapability);
            // Don't send DST unless the device says it needs it
            mNeedsDST = false;

            mParams.SetSupportsConcurrentConnection(mDeviceCommissioningInfo.supportsConcurrentConnection);

            if (mParams.GetCheckForMatchingFabric())
            {
                NodeId nodeId = mDeviceCommissioningInfo.remoteNodeId;
                if (nodeId != kUndefinedNodeId)
                {
                    mParams.SetRemoteNodeId(nodeId);
                }
            }

            mNeedIcdRegistration = false;
            if (mParams.GetICDRegistrationStrategy() != ICDRegistrationStrategy::kIgnore)
            {
                if (mDeviceCommissioningInfo.icd.isLIT && mDeviceCommissioningInfo.icd.checkInProtocolSupport)
                {
                    mNeedIcdRegistration = true;
                    ChipLogDetail(Controller, "AutoCommissioner: ICD supports the check-in protocol.");
                }
                else if (mParams.GetICDStayActiveDurationMsec().HasValue())
                {
                    ChipLogDetail(Controller, "AutoCommissioner: Clear ICD StayActiveDurationMsec");
                    mParams.ClearICDStayActiveDurationMsec();
                }
            }

            break;
        }
        case CommissioningStage::kConfigureTimeZone:
            mNeedsDST = report.Get<TimeZoneResponseInfo>().requiresDSTOffsets;
            break;
        case CommissioningStage::kSendPAICertificateRequest: {
            auto reportPAISpan = report.Get<RequestedCertificate>().certificate;

            mPAI.CopyFromSpan(reportPAISpan);
            mParams.SetPAI(mPAI.Span());
            break;
        }
        case CommissioningStage::kSendDACCertificateRequest: {
            auto reportDACSpan = report.Get<RequestedCertificate>().certificate;

            mDAC.CopyFromSpan(reportDACSpan);
            mParams.SetDAC(ByteSpan(mDAC.Span()));
            break;
        }
        case CommissioningStage::kSendAttestationRequest: {
            auto & elements  = report.Get<AttestationResponse>().attestationElements;
            auto & signature = report.Get<AttestationResponse>().signature;
            if (elements.size() > sizeof(mAttestationElements))
            {
                ChipLogError(Controller, "AutoCommissioner attestationElements buffer size %u larger than cache size %u",
                             static_cast<unsigned>(elements.size()), static_cast<unsigned>(sizeof(mAttestationElements)));
                return CHIP_ERROR_MESSAGE_TOO_LONG;
            }
            memcpy(mAttestationElements, elements.data(), elements.size());
            mAttestationElementsLen = static_cast<uint16_t>(elements.size());
            mParams.SetAttestationElements(ByteSpan(mAttestationElements, elements.size()));
            ChipLogDetail(Controller, "AutoCommissioner setting attestationElements buffer size %u/%u",
                          static_cast<unsigned>(elements.size()),
                          static_cast<unsigned>(mParams.GetAttestationElements().Value().size()));

            if (signature.size() > sizeof(mAttestationSignature))
            {
                ChipLogError(Controller,
                             "AutoCommissioner attestationSignature buffer size %u larger than "
                             "cache size %u",
                             static_cast<unsigned>(signature.size()), static_cast<unsigned>(sizeof(mAttestationSignature)));
                return CHIP_ERROR_MESSAGE_TOO_LONG;
            }
            memcpy(mAttestationSignature, signature.data(), signature.size());
            mAttestationSignatureLen = static_cast<uint16_t>(signature.size());
            mParams.SetAttestationSignature(ByteSpan(mAttestationSignature, signature.size()));

            // TODO: Does this need to be done at runtime? Seems like this could be done earlier and we wouldn't need to hold a
            // reference to the operational credential delegate here
            if (mOperationalCredentialsDelegate != nullptr)
            {
                uint8_t csrNonceBytes[sizeof(mCSRNonce)];
                MutableByteSpan nonce(csrNonceBytes);
                CHIP_ERROR csrError = mOperationalCredentialsDelegate->ObtainCsrNonce(nonce);
                if (csrError != CHIP_ERROR_NOT_IMPLEMENTED)
                {
                    ReturnErrorOnFailure(csrError);

                    MutableByteSpan savedCSRNonce(mCSRNonce);
                    ReturnErrorOnFailure(CopySpanToMutableSpan(nonce, savedCSRNonce));
                    mParams.SetCSRNonce(savedCSRNonce);
                }
            }
            break;
        }
        case CommissioningStage::kSendOpCertSigningRequest: {
            NOCChainGenerationParameters nocParams;
            nocParams.nocsrElements = report.Get<CSRResponse>().nocsrElements;
            nocParams.signature     = report.Get<CSRResponse>().signature;
            mParams.SetNOCChainGenerationParameters(nocParams);
        }
        break;
        case CommissioningStage::kGenerateNOCChain:
            // For NOC chain generation, we re-use the buffers. NOCChainGenerated triggers the next stage before
            // storing the returned certs, so just return here without triggering the next stage.
            return NOCChainGenerated(report.Get<NocChain>().noc, report.Get<NocChain>().icac, report.Get<NocChain>().rcac,
                                     report.Get<NocChain>().ipk, report.Get<NocChain>().adminSubject);
        case CommissioningStage::kICDGetRegistrationInfo:
            // Noting to do. The ICD registation info is handled elsewhere.
            break;
        case CommissioningStage::kICDRegistration:
            // Noting to do. DevicePairingDelegate will handle this.
            break;
        case CommissioningStage::kFindOperationalForStayActive:
        case CommissioningStage::kFindOperationalForCommissioningComplete:
            mOperationalDeviceProxy = report.Get<OperationalNodeFoundData>().operationalProxy;
            break;
        case CommissioningStage::kCleanup:
            CleanupCommissioning();
            return CHIP_NO_ERROR;
        default:
            break;
        }
    }

    CommissioningStage nextStage = GetNextCommissioningStage(report.stageCompleted, err);
    if (nextStage == CommissioningStage::kError)
    {
        return CHIP_ERROR_INCORRECT_STATE;
    }

    // If GetNextCommissioningStage indicated a failure, don't lose track of
    // that.  But don't overwrite any existing failures we had hanging
    // around.
    if (completionStatus.err == CHIP_NO_ERROR)
    {
        completionStatus.err = err;
    }
    mParams.SetCompletionStatus(completionStatus);

    return PerformStep(nextStage);
}

DeviceProxy * AutoCommissioner::GetDeviceProxyForStep(CommissioningStage nextStage)
{
    if (nextStage == CommissioningStage::kSendComplete || nextStage == CommissioningStage::kICDSendStayActive ||
        (nextStage == CommissioningStage::kCleanup && mOperationalDeviceProxy.GetDeviceId() != kUndefinedNodeId))
    {
        return &mOperationalDeviceProxy;
    }
    return mCommissioneeDeviceProxy;
}

CHIP_ERROR AutoCommissioner::PerformStep(CommissioningStage nextStage)
{
    DeviceProxy * proxy = GetDeviceProxyForStep(nextStage);
    if (proxy == nullptr)
    {
        ChipLogError(Controller, "Invalid device for commissioning");
        return CHIP_ERROR_INCORRECT_STATE;
    }
    // Perform any last minute parameter adjustments before calling the commissioner object
    switch (nextStage)
    {
    case CommissioningStage::kConfigureTimeZone:
        if (mParams.GetTimeZone().Value().size() > mDeviceCommissioningInfo.maxTimeZoneSize)
        {
            mParams.SetTimeZone(app::DataModel::List<app::Clusters::TimeSynchronization::Structs::TimeZoneStruct::Type>(
                mParams.GetTimeZone().Value().SubSpan(0, mDeviceCommissioningInfo.maxTimeZoneSize)));
        }
        break;
    case CommissioningStage::kConfigureDSTOffset:
        if (mParams.GetDSTOffsets().Value().size() > mDeviceCommissioningInfo.maxDSTSize)
        {
            mParams.SetDSTOffsets(app::DataModel::List<app::Clusters::TimeSynchronization::Structs::DSTOffsetStruct::Type>(
                mParams.GetDSTOffsets().Value().SubSpan(0, mDeviceCommissioningInfo.maxDSTSize)));
        }
        break;
    default:
        break;
    }

    mCommissioner->PerformCommissioningStep(proxy, nextStage, mParams, this, GetEndpoint(nextStage),
                                            GetCommandTimeout(proxy, nextStage));
    return CHIP_NO_ERROR;
}

} // namespace Controller
} // namespace chip