src/app/EventLogging.h

/*
 *
 *    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.
 */

#pragma once

#include <app/ConcreteEventPath.h>
#include <app/EventLoggingDelegate.h>
#include <app/EventManagement.h>
#include <app/data-model/Encode.h>
#include <app/data-model/FabricScoped.h>
#include <app/data-model/List.h> // So we can encode lists

namespace chip {
namespace app {

template <typename T>
class EventLogger : public EventLoggingDelegate
{
public:
    EventLogger(const T & aEventData) : mEventData(aEventData){};
    CHIP_ERROR WriteEvent(chip::TLV::TLVWriter & aWriter) final override
    {
        return DataModel::Encode(aWriter, TLV::ContextTag(to_underlying(EventDataIB::Tag::kData)), mEventData);
    }

private:
    const T & mEventData;
};

/**
 * @brief
 *   Log an event via a EventLoggingDelegate, with options.
 *
 * The EventLoggingDelegate writes the event metadata and calls the `apDelegate`
 * with an TLV::TLVWriter reference so that the user code can emit
 * the event data directly into the event log.  This form of event
 * logging minimizes memory consumption, as event data is serialized
 * directly into the target buffer.  The event data MUST contain
 * context tags to be interpreted within the schema identified by
 * `ClusterID` and `EventId`.
 *
 * LogEvent has 2 variant, one for fabric-scoped events and one for non-fabric-scoped events.
 * @param[in] aEventData  The event cluster object
 * @param[in] aEndpoint    The current cluster's Endpoint Id
 * @param[in] aUrgent    The EventOption Type, kUrgent or kNotUrgent
 * @param[out] aEventNumber The event Number if the event was written to the
 *                         log, 0 otherwise. The Event number is expected to monotonically increase.
 *
 * TODO: Revisit spec foc nullable fabric index in event.
 *
 * @return CHIP_ERROR  CHIP Error Code
 */
template <typename T,
          std::enable_if_t<DataModel::IsFabricScoped<T>::value &&
                               std::is_same<decltype(std::declval<T>().GetFabricIndex()), FabricIndex>::value,
                           bool> = true>
CHIP_ERROR LogEvent(const T & aEventData, EndpointId aEndpoint, EventNumber & aEventNumber,
                    EventOptions::Type aUrgent = EventOptions::Type::kNotUrgent)
{
    EventLogger<T> eventData(aEventData);
    ConcreteEventPath path(aEndpoint, aEventData.GetClusterId(), aEventData.GetEventId());
    EventManagement & logMgmt = chip::app::EventManagement::GetInstance();
    EventOptions eventOptions;
    eventOptions.mUrgent      = aUrgent;
    eventOptions.mPath        = path;
    eventOptions.mPriority    = aEventData.GetPriorityLevel();
    eventOptions.mFabricIndex = aEventData.GetFabricIndex();
    return logMgmt.LogEvent(&eventData, eventOptions, aEventNumber);
}

template <typename T,
          std::enable_if_t<DataModel::IsFabricScoped<T>::value &&
                               std::is_same<decltype(std::declval<T>().GetFabricIndex()), DataModel::Nullable<FabricIndex>>::value,
                           bool> = true>
CHIP_ERROR LogEvent(const T & aEventData, EndpointId aEndpoint, EventNumber & aEventNumber,
                    EventOptions::Type aUrgent = EventOptions::Type::kNotUrgent)
{
    EventLogger<T> eventData(aEventData);
    ConcreteEventPath path(aEndpoint, aEventData.GetClusterId(), aEventData.GetEventId());
    EventManagement & logMgmt = chip::app::EventManagement::GetInstance();
    EventOptions eventOptions;
    eventOptions.mUrgent      = aUrgent;
    eventOptions.mPath        = path;
    eventOptions.mPriority    = aEventData.GetPriorityLevel();
    eventOptions.mFabricIndex = aEventData.GetFabricIndex().IsNull() ? kUndefinedFabricIndex : aEventData.GetFabricIndex().Value();
    return logMgmt.LogEvent(&eventData, eventOptions, aEventNumber);
}

template <typename T, std::enable_if_t<!DataModel::IsFabricScoped<T>::value, bool> = true>
CHIP_ERROR LogEvent(const T & aEventData, EndpointId aEndpoint, EventNumber & aEventNumber,
                    EventOptions::Type aUrgent = EventOptions::Type::kNotUrgent)
{
    EventLogger<T> eventData(aEventData);
    ConcreteEventPath path(aEndpoint, aEventData.GetClusterId(), aEventData.GetEventId());
    EventManagement & logMgmt = chip::app::EventManagement::GetInstance();
    EventOptions eventOptions;
    eventOptions.mUrgent   = aUrgent;
    eventOptions.mPath     = path;
    eventOptions.mPriority = aEventData.GetPriorityLevel();
    return logMgmt.LogEvent(&eventData, eventOptions, aEventNumber);
}

} // namespace app
} // namespace chip