src/app/clusters/scenes/SceneTableImpl.h

/**
 *
 *    Copyright (c) 2022 Project CHIP Authors
 *
 *    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/clusters/scenes/ExtensionFieldSetsImpl.h>
#include <app/clusters/scenes/SceneTable.h>
#include <lib/core/DataModelTypes.h>
#include <lib/support/CommonIterator.h>
#include <lib/support/PersistentData.h>
#include <lib/support/Pool.h>

namespace chip {
namespace scenes {

using clusterId = chip::ClusterId;

/// @brief Default implementation of handler, handle EFS from add scene and view scene commands for any cluster
///        The implementation of SerializeSave and ApplyScene were omitted and must be implemented in a way that
///        is compatible with the SerializeAdd output in order to function with the Default Scene Handler.
///        It is worth noting that this implementation is very memory consuming. In the current worst case,
///        (Color control cluster), the Extension Field Set's value pair list TLV occupies 99 bytes of memory
class DefaultSceneHandlerImpl : public scenes::SceneHandler
{
public:
    static constexpr uint8_t kMaxValueSize = 4;
    static constexpr uint8_t kMaxAvPair    = 15;

    DefaultSceneHandlerImpl() = default;
    ~DefaultSceneHandlerImpl() override{};

    /// @brief From command AddScene, allows handler to filter through clusters in command to serialize only the supported ones.
    /// @param endpoint[in] Endpoint ID
    /// @param extensionFieldSet[in] ExtensionFieldSets provided by the AddScene Command, pre initialized
    /// @param serialisedBytes[out] Buffer to fill from the ExtensionFieldSet in command
    /// @return CHIP_NO_ERROR if successful, CHIP_ERROR_INVALID_ARGUMENT if the cluster is not supported, CHIP_ERROR value otherwise
    virtual CHIP_ERROR SerializeAdd(EndpointId endpoint,
                                    const app::Clusters::Scenes::Structs::ExtensionFieldSet::DecodableType & extensionFieldSet,
                                    MutableByteSpan & serializedBytes) override
    {
        app::Clusters::Scenes::Structs::AttributeValuePair::DecodableType aVPair;
        TLV::TLVWriter writer;
        TLV::TLVType outer;
        size_t pairTotal  = 0;
        uint8_t pairCount = 0;

        // Verify size of list
        ReturnErrorOnFailure(extensionFieldSet.attributeValueList.ComputeSize(&pairTotal));
        VerifyOrReturnError(pairTotal <= ArraySize(mAVPairs), CHIP_ERROR_BUFFER_TOO_SMALL);

        auto pair_iterator = extensionFieldSet.attributeValueList.begin();
        while (pair_iterator.Next())
        {
            aVPair                             = pair_iterator.GetValue();
            mAVPairs[pairCount].attributeID    = aVPair.attributeID;
            mAVPairs[pairCount].attributeValue = aVPair.attributeValue;
            pairCount++;
        }
        ReturnErrorOnFailure(pair_iterator.GetStatus());

        app::DataModel::List<app::Clusters::Scenes::Structs::AttributeValuePair::Type> attributeValueList;
        attributeValueList = mAVPairs;
        attributeValueList.reduce_size(pairCount);

        writer.Init(serializedBytes);
        ReturnErrorOnFailure(writer.StartContainer(TLV::AnonymousTag(), TLV::kTLVType_Structure, outer));
        ReturnErrorOnFailure(app::DataModel::Encode(
            writer, TLV::ContextTag(app::Clusters::Scenes::Structs::ExtensionFieldSet::Fields::kAttributeValueList),
            attributeValueList));
        ReturnErrorOnFailure(writer.EndContainer(outer));

        return CHIP_NO_ERROR;
    }

    /// @brief Simulates taking data from nvm and loading it in a command object if the cluster is supported by the endpoint
    /// @param endpoint target endpoint
    /// @param cluster  target cluster
    /// @param serialisedBytes data to deserialize into EFS
    /// @return CHIP_NO_ERROR if Extension Field Set was successfully populated, CHIP_ERROR_INVALID_ARGUMENT if the cluster is not
    /// supported, specific CHIP_ERROR otherwise
    virtual CHIP_ERROR Deserialize(EndpointId endpoint, ClusterId cluster, const ByteSpan & serialisedBytes,
                                   app::Clusters::Scenes::Structs::ExtensionFieldSet::Type & extensionFieldSet) override
    {
        app::DataModel::DecodableList<app::Clusters::Scenes::Structs::AttributeValuePair::DecodableType> attributeValueList;
        app::Clusters::Scenes::Structs::AttributeValuePair::DecodableType decodePair;

        TLV::TLVReader reader;
        TLV::TLVType outer;
        size_t pairTotal  = 0;
        uint8_t pairCount = 0;

        extensionFieldSet.clusterID = cluster;
        reader.Init(serialisedBytes);
        ReturnErrorOnFailure(reader.Next(TLV::kTLVType_Structure, TLV::AnonymousTag()));
        ReturnErrorOnFailure(reader.EnterContainer(outer));
        ReturnErrorOnFailure(reader.Next(
            TLV::kTLVType_Array, TLV::ContextTag(app::Clusters::Scenes::Structs::ExtensionFieldSet::Fields::kAttributeValueList)));
        attributeValueList.Decode(reader);

        // Verify size of list
        ReturnErrorOnFailure(attributeValueList.ComputeSize(&pairTotal));
        VerifyOrReturnError(pairTotal <= ArraySize(mAVPairs), CHIP_ERROR_BUFFER_TOO_SMALL);

        auto pair_iterator = attributeValueList.begin();
        while (pair_iterator.Next())
        {
            decodePair                         = pair_iterator.GetValue();
            mAVPairs[pairCount].attributeID    = decodePair.attributeID;
            mAVPairs[pairCount].attributeValue = decodePair.attributeValue;
            pairCount++;
        };
        ReturnErrorOnFailure(pair_iterator.GetStatus());

        ReturnErrorOnFailure(reader.ExitContainer(outer));
        extensionFieldSet.attributeValueList = mAVPairs;
        extensionFieldSet.attributeValueList.reduce_size(pairCount);

        return CHIP_NO_ERROR;
    }

private:
    app::Clusters::Scenes::Structs::AttributeValuePair::Type mAVPairs[kMaxAvPair];
};

/**
 * @brief Implementation of a storage in nonvolatile storage of the scene table.
 *
 * DefaultSceneTableImpl is an implementation that allows to store scenes using PersistentStorageDelegate.
 * It handles the storage of scenes by their ID, GroupID and EnpointID over multiple fabrics.
 * It is meant to be used exclusively when the scene cluster is enable for at least one endpoint
 * on the device.
 */
class DefaultSceneTableImpl : public SceneTable<scenes::ExtensionFieldSetsImpl>
{
public:
    DefaultSceneTableImpl() {}

    ~DefaultSceneTableImpl() override {}

    CHIP_ERROR Init(PersistentStorageDelegate * storage) override;
    void Finish() override;

    // Global scene count
    CHIP_ERROR GetGlobalSceneCount(uint8_t & scene_count) override;

    // Data
    CHIP_ERROR GetRemainingCapacity(FabricIndex fabric_index, uint8_t & capacity) override;
    CHIP_ERROR SetSceneTableEntry(FabricIndex fabric_index, const SceneTableEntry & entry) override;
    CHIP_ERROR GetSceneTableEntry(FabricIndex fabric_index, SceneStorageId scene_id, SceneTableEntry & entry) override;
    CHIP_ERROR RemoveSceneTableEntry(FabricIndex fabric_index, SceneStorageId scene_id) override;
    CHIP_ERROR RemoveSceneTableEntryAtPosition(FabricIndex fabric_index, SceneIndex scene_idx) override;

    // Groups
    CHIP_ERROR GetAllSceneIdsInGroup(FabricIndex fabric_index, GroupId group_id, Span<SceneId> & scene_list) override;
    CHIP_ERROR DeleteAllScenesInGroup(FabricIndex fabric_index, GroupId group_id) override;

    // SceneHandlers
    void RegisterHandler(SceneHandler * handler) override;
    void UnregisterHandler(SceneHandler * handler) override;
    void UnregisterAllHandlers() override;

    // Extension field sets operation

    CHIP_ERROR SceneSaveEFS(SceneTableEntry & scene) override;
    CHIP_ERROR SceneApplyEFS(const SceneTableEntry & scene) override;

    // Fabrics
    CHIP_ERROR RemoveFabric(FabricIndex fabric_index) override;

    // Iterators
    SceneEntryIterator * IterateSceneEntries(FabricIndex fabric_index) override;

protected:
    // This constructor is meant for test purposes, it allows to change the defined max for scenes per fabric and global, which
    // allows to simulate OTA where this value was changed
    DefaultSceneTableImpl(uint8_t maxScenesPerFabric = scenes::kMaxScenesPerFabric,
                          uint8_t maxScenesGlobal    = scenes::kMaxScenesGlobal) :
        mMaxScenesPerFabric(maxScenesPerFabric),
        mMaxScenesGlobal(maxScenesGlobal)
    {}

    // Global scene count
    CHIP_ERROR SetGlobalSceneCount(const uint8_t & scene_count);

    // wrapper function around emberAfGetClustersFromEndpoint to allow override when testing
    virtual uint8_t GetClustersFromEndpoint(EndpointId endpoint, ClusterId * clusterList, uint8_t listLen);

    class SceneEntryIteratorImpl : public SceneEntryIterator
    {
    public:
        SceneEntryIteratorImpl(DefaultSceneTableImpl & provider, FabricIndex fabric_index, uint8_t maxScenesPerFabric,
                               uint8_t maxScenesGlobal);
        size_t Count() override;
        bool Next(SceneTableEntry & output) override;
        void Release() override;

    protected:
        DefaultSceneTableImpl & mProvider;
        FabricIndex mFabric = kUndefinedFabricIndex;
        SceneIndex mNextSceneIdx;
        SceneIndex mSceneIndex = 0;
        uint8_t mTotalScenes   = 0;
        uint8_t mMaxScenesPerFabric;
        uint8_t mMaxScenesGlobal;
    };
    bool IsInitialized() { return (mStorage != nullptr); }

    const uint8_t mMaxScenesPerFabric          = kMaxScenesPerFabric;
    const uint8_t mMaxScenesGlobal             = kMaxScenesGlobal;
    chip::PersistentStorageDelegate * mStorage = nullptr;
    ObjectPool<SceneEntryIteratorImpl, kIteratorsMax> mSceneEntryIterators;
}; // class DefaultSceneTableImpl

} // namespace scenes
} // namespace chip