device_descriptions.cpp

/*
 * Copyright (c) 2022 dresden elektronik ingenieurtechnik gmbh.
 * All rights reserved.
 *
 * The software in this package is published under the terms of the BSD
 * style license a copy of which has been included with this distribution in
 * the LICENSE.txt file.
 *
 */

#include <QDirIterator>
#include <QFile>
#include <QJsonArray>
#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonValue>
#include <QSettings>
#include <deconz/dbg_trace.h>
#include "device_ddf_init.h"
#include "device_descriptions.h"
#include "device_js/device_js.h"
#include "event.h"
#include "resource.h"

#define HND_MIN_LOAD_COUNTER 1
#define HND_MAX_LOAD_COUNTER 15
#define HND_MAX_DESCRIPTIONS 16383
#define HND_MAX_ITEMS        1023
#define HND_MAX_SUB_DEVS     15

/*! \union ItemHandlePack

    Packs location to an DDF item into a opaque 32-bit unsigned int handle.
    The DDF item lookup complexity is O(1) via DDF_GetItem() function.
 */
union ItemHandlePack
{
    // 32-bit memory layout
    // llll dddd dddd dddd ddss ssii iiii iiii
    struct {
        //! Max: 15, check for valid handle, for each DDF reload the counter is incremented (wraps to 0).
        unsigned int loadCounter : 4;
        unsigned int description : 14; //! Max: 16383, index into descriptions[].
        unsigned int subDevice: 4;     //! Max: 15, index into description -> subdevices[]
        unsigned int item : 10;        //! Max: 1023, index into subdevice -> items[]
    };
    quint32 handle;
};

static DeviceDescriptions *_instance = nullptr;
static DeviceDescriptionsPrivate *_priv = nullptr;

class DeviceDescriptionsPrivate
{
public:
    uint loadCounter = HND_MIN_LOAD_COUNTER;
    std::map<QString,QString> constants;
    std::vector<DeviceDescription::Item> genericItems;
    std::vector<DeviceDescription> descriptions;

    DeviceDescription invalidDescription;
    DeviceDescription::Item invalidItem;
    DeviceDescription::SubDevice invalidSubDevice;

    QStringList enabledStatusFilter;

    std::vector<DDF_SubDeviceDescriptor> subDevices;

    std::vector<DDF_FunctionDescriptor> readFunctions;
    std::vector<DDF_FunctionDescriptor> writeFunctions;
    std::vector<DDF_FunctionDescriptor> parseFunctions;
};

static bool DDF_ReadConstantsJson(const QString &path, std::map<QString,QString> *constants);
static DeviceDescription::Item DDF_ReadItemFile(const QString &path);
static std::vector<DeviceDescription> DDF_ReadDeviceFile(const QString &path);
static DDF_SubDeviceDescriptor DDF_ReadSubDeviceFile(const QString &path);
static DeviceDescription DDF_MergeGenericItems(const std::vector<DeviceDescription::Item> &genericItems, const DeviceDescription &ddf);
static DeviceDescription::Item *DDF_GetItemMutable(const ResourceItem *item);
static void DDF_UpdateItemHandles(std::vector<DeviceDescription> &descriptions, uint loadCounter);
DeviceDescription DDF_LoadScripts(const DeviceDescription &ddf);

/*! Constructor. */
DeviceDescriptions::DeviceDescriptions(QObject *parent) :
    QObject(parent),
    d_ptr2(new DeviceDescriptionsPrivate)
{
    _instance = this;
    _priv = d_ptr2;

    {  // Parse function as shown in the DDF editor.
        DDF_FunctionDescriptor fn;
        fn.name = "zcl";
        fn.description = "Generic function to parse ZCL attributes and commands.";

        DDF_FunctionDescriptor::Parameter param;

        param.name = "Endpoint";
        param.key = "ep";
        param.description = "255 means any endpoint, 0 means auto selected from subdevice.";
        param.dataType = DataTypeUInt8;
        param.defaultValue = 0;
        param.isOptional = 1;
        param.isHexString = 0;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Cluster ID";
        param.key = "cl";
        param.description = "As string hex value";
        param.dataType = DataTypeUInt16;
        param.defaultValue = 0;
        param.isOptional = 0;
        param.isHexString = 1;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Attribute ID";
        param.key = "at";
        param.description = "As string hex value";
        param.dataType = DataTypeUInt16;
        param.defaultValue = 0;
        param.isOptional = 0;
        param.isHexString = 1;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Manufacturer code";
        param.key = "mf";
        param.description = "As string hex value.";
        param.dataType = DataTypeUInt16;
        param.defaultValue = 0;
        param.isOptional = 1;
        param.isHexString = 1;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Javascript file";
        param.key = "script";
        param.description = "Relative path of a Javascript .js file.";
        param.dataType = DataTypeString;
        param.defaultValue = {};
        param.isOptional = 1;
        param.isHexString = 0;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Expression";
        param.key = "eval";
        param.description = "Javascript expression to transform the raw value.";
        param.dataType = DataTypeString;
        param.defaultValue = QLatin1String("Item.val = Attr.val");
        param.isOptional = 1;
        param.isHexString = 0;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        d_ptr2->parseFunctions.push_back(fn);
    }

    {  // Read function as shown in the DDF editor.
        DDF_FunctionDescriptor fn;
        fn.name = "zcl";
        fn.description = "Generic function to read ZCL attributes.";

        DDF_FunctionDescriptor::Parameter param;

        param.name = "Endpoint";
        param.key = "ep";
        param.description = "255 means any endpoint, 0 means auto selected from subdevice.";
        param.dataType = DataTypeUInt8;
        param.defaultValue = 255;
        param.isOptional = 0;
        param.isHexString = 0;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Cluster ID";
        param.key = "cl";
        param.description = "As string hex value";
        param.dataType = DataTypeUInt16;
        param.defaultValue = 0;
        param.isOptional = 0;
        param.isHexString = 1;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Attribute ID";
        param.key = "at";
        param.description = "As string hex value";
        param.dataType = DataTypeUInt16;
        param.defaultValue = 0;
        param.isOptional = 0;
        param.isHexString = 1;
        param.supportsArray = 1;
        fn.parameters.push_back(param);

        param.name = "Manufacturer code";
        param.key = "mf";
        param.description = "As string hex value.";
        param.dataType = DataTypeUInt16;
        param.defaultValue = 0;
        param.isOptional = 1;
        param.isHexString = 1;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        d_ptr2->readFunctions.push_back(fn);
    }

    {
        DDF_FunctionDescriptor fn;
        fn.name = "ias:zonestatus";
        fn.description = "Generic function to parse IAS ZONE status change notifications or zone status from read/report command.";

        DDF_FunctionDescriptor::Parameter param;

        param.name = "IAS Zone status mask";
        param.key = "mask";
        param.description = "Sets the bitmask for Alert1 and Alert2 item of the IAS Zone status.";
        param.dataType = DataTypeString;
        param.defaultValue = QLatin1String("alarm1,alarm2");
        param.isOptional = 1;
        param.isHexString = 0;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        d_ptr2->parseFunctions.push_back(fn);
    }

    {
        DDF_FunctionDescriptor fn;
        fn.name = "numtostr";
        fn.description = "Generic function to to convert number to string.";

        DDF_FunctionDescriptor::Parameter param;

        param.name = "Source item";
        param.key = "srcitem";
        param.description = "The source item holding the number.";
        param.dataType = DataTypeString;
        param.defaultValue = 0;
        param.isOptional = 0;
        param.isHexString = 0;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Operator";
        param.key = "op";
        param.description = "Comparison operator (lt | le | eq | gt | ge)";
        param.dataType = DataTypeString;
        param.defaultValue = 0;
        param.isOptional = 0;
        param.isHexString = 0;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Mapping";
        param.key = "to";
        param.description = "Array of (num, string) mappings";
        param.dataType = DataTypeString;
        param.defaultValue = 0;
        param.isOptional = 0;
        param.isHexString = 0;
        param.supportsArray = 1;
        fn.parameters.push_back(param);

        d_ptr2->parseFunctions.push_back(fn);
    }
    
    {
        DDF_FunctionDescriptor fn;
        fn.name = "time";
        fn.description = "Specialized function to parse time, local and last set time from read/report commands of the time cluster and auto-sync time if needed.";

        d_ptr2->parseFunctions.push_back(fn);
    }

    {
        DDF_FunctionDescriptor fn;
        fn.name = "xiaomi:special";
        fn.description = "Generic function to parse custom Xiaomi attributes and commands.";

        DDF_FunctionDescriptor::Parameter param;

        param.name = "Endpoint";
        param.key = "ep";
        param.description = "Source endpoint of the incoming command, default value 255 means any endpoint.";
        param.dataType = DataTypeUInt8;
        param.defaultValue = 255;
        param.isOptional = 1;
        param.isHexString = 0;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Attribute ID";
        param.key = "at";
        param.description = "The attribute to parse, shall be 0xff01, 0xff02 or 0x00f7";
        param.dataType = DataTypeUInt16;
        param.defaultValue = 0;
        param.isOptional = 0;
        param.isHexString = 1;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Index";
        param.key = "idx";
        param.description = "A 8-bit string hex value.";
        param.dataType = DataTypeUInt8;
        param.defaultValue = 0;
        param.isOptional = 0;
        param.isHexString = 1;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Expression";
        param.key = "eval";
        param.description = "Javascript expression to transform the raw value.";
        param.dataType = DataTypeString;
        param.defaultValue = {};
        param.isOptional = 0;
        param.isHexString = 0;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        d_ptr2->parseFunctions.push_back(fn);
    }

    {
        DDF_FunctionDescriptor fn;
        fn.name = "tuya";
        fn.description = "Generic function to read all Tuya datapoints. It has no parameters.";
        d_ptr2->readFunctions.push_back(fn);
    }

    {
        DDF_FunctionDescriptor fn;
        fn.name = "tuya";
        fn.description = "Generic function to parse Tuya data.";

        DDF_FunctionDescriptor::Parameter param;

        param.name = "Datapoint";
        param.key = "dpid";
        param.description = "1-255 the datapoint ID.";
        param.dataType = DataTypeUInt8;
        param.defaultValue = 0;
        param.isOptional = 0;
        param.isHexString = 0;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Javascript file";
        param.key = "script";
        param.description = "Relative path of a Javascript .js file.";
        param.dataType = DataTypeString;
        param.defaultValue = {};
        param.isOptional = 1;
        param.isHexString = 0;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        param.name = "Expression";
        param.key = "eval";
        param.description = "Javascript expression to transform the raw value.";
        param.dataType = DataTypeString;
        param.defaultValue = QLatin1String("Item.val = Attr.val");
        param.isOptional = 1;
        param.isHexString = 0;
        param.supportsArray = 0;
        fn.parameters.push_back(param);

        d_ptr2->parseFunctions.push_back(fn);
    }
}

/*! Destructor. */
DeviceDescriptions::~DeviceDescriptions()
{
    Q_ASSERT(_instance == this);
    _instance = nullptr;
    _priv = nullptr;
    Q_ASSERT(d_ptr2);
    delete d_ptr2;
    d_ptr2 = nullptr;
}

void DeviceDescriptions::setEnabledStatusFilter(const QStringList &filter)
{
    if (d_ptr2->enabledStatusFilter != filter)
    {
        d_ptr2->enabledStatusFilter = filter;
        DBG_Printf(DBG_INFO, "DDF enabled for %s status\n", qPrintable(filter.join(QLatin1String(", "))));
    }
}

const QStringList &DeviceDescriptions::enabledStatusFilter() const
{
    return d_ptr2->enabledStatusFilter;
}

/*! Returns the DeviceDescriptions singleton instance.
 */
DeviceDescriptions *DeviceDescriptions::instance()
{
    Q_ASSERT(_instance);
    return _instance;
}

bool DDF_IsStatusEnabled(const QString &status)
{
    if (_priv)
    {
        return _priv->enabledStatusFilter.contains(status, Qt::CaseInsensitive);
    }
    return false;
}

/*! Helper to transform hard C++ coded parse functions to DDF.
 */
void DDF_AnnoteZclParse1(int line, const char *file, const Resource *resource, ResourceItem *item, quint8 ep, quint16 clusterId, quint16 attributeId, const char *eval)
{
    DBG_Assert(resource);
    DBG_Assert(item);
    DBG_Assert(eval);

    if (!_instance || !resource || !item || !eval)
    {
        return;
    }

    if (item->ddfItemHandle() == DeviceDescription::Item::InvalidItemHandle)
    {
        const Device *device = nullptr;
        if (resource->parentResource())
        {
            device = static_cast<const Device*>(resource->parentResource());
        }

        if (!device)
        {
            return;
        }

        const auto *uniqueId = resource->item(RAttrUniqueId);
        if (!uniqueId)
        {
            return;
        }

        auto &ddf = _instance->get(device);
        if (!ddf.isValid())
        {
            return;
        }

        // this is pretty heavy but will be removed later
        const QStringList u = uniqueId->toString().split(QLatin1Char('-'), SKIP_EMPTY_PARTS);

        for (const auto &sub : ddf.subDevices)
        {
            if (u.size() != sub.uniqueId.size())
            {
                continue;
            }

            bool ok = true;
            for (int i = 1; i < qMin(u.size(), sub.uniqueId.size()); i++)
            {
                if (u[i].toUInt(0, 16) != sub.uniqueId[i].toUInt(0, 16))
                {
                    ok = false;
                }
            }

            if (!ok)
            {
                continue;
            }

            for (const auto &ddfItem : sub.items)
            {
                if (ddfItem.name == item->descriptor().suffix)
                {
                    item->setDdfItemHandle(ddfItem.handle);
                    break;
                }
            }

            break;
        }
    }

    if (item->ddfItemHandle() != DeviceDescription::Item::InvalidItemHandle)
    {
        DeviceDescription::Item *ddfItem = DDF_GetItemMutable(item);

        if (ddfItem && ddfItem->isValid())
        {
            if (ddfItem->parseParameters.isNull())
            {
                char buf[255];

                QVariantMap param;
                param[QLatin1String("ep")] = int(ep);
                snprintf(buf, sizeof(buf), "0x%04X", clusterId);
                param[QLatin1String("cl")] = QLatin1String(buf);
                snprintf(buf, sizeof(buf), "0x%04X", attributeId);
                param[QLatin1String("at")] = QLatin1String(buf);
                param[QLatin1String("eval")] = QLatin1String(eval);

                size_t fileLen = strlen(file);
                const char *fileName = file + fileLen;

                for (size_t i = fileLen; i > 0; i--, fileName--)
                {
                    if (*fileName == '/')
                    {
                        fileName++;
                        break;
                    }
                }

                snprintf(buf, sizeof(buf), "%s:%d", fileName, line);
                param[QLatin1String("cppsrc")] = QLatin1String(buf);

                ddfItem->parseParameters = param;

                DBG_Printf(DBG_DDF, "DDF %s:%d: %s updated ZCL function cl: 0x%04X, at: 0x%04X, eval: %s\n", fileName, line, qPrintable(resource->item(RAttrUniqueId)->toString()), clusterId, attributeId, eval);
            }
        }
    }
}

void DeviceDescriptions::handleEvent(const Event &event)
{
    if (event.what() == REventDDFInitRequest)
    {
        handleDDFInitRequest(event);
    }
    else if (event.what() == REventDDFReload)
    {
        readAll(); // todo read only device specific files?
    }
}

/*! Get the DDF object for a \p resource.
    \returns The DDF object, DeviceDescription::isValid() to check for success.
 */
const DeviceDescription &DeviceDescriptions::get(const Resource *resource, DDF_MatchControl match) const
{
    Q_ASSERT(resource);
    Q_ASSERT(resource->item(RAttrModelId));
    Q_ASSERT(resource->item(RAttrManufacturerName));

    Q_D(const DeviceDescriptions);

    const auto modelId = resource->item(RAttrModelId)->toString();
    const auto manufacturer = resource->item(RAttrManufacturerName)->toString();
    const auto manufacturerConstant = stringToConstant(manufacturer);

    auto i = d->descriptions.begin();

    for (;;)
    {
        i = std::find_if(i, d->descriptions.end(), [&modelId, &manufacturer, &manufacturerConstant](const DeviceDescription &ddf)
        {
            // compare manufacturer name case insensitive
            const auto m = std::find_if(ddf.manufacturerNames.cbegin(), ddf.manufacturerNames.cend(),
                                       [&](const auto &x){ return x.compare(manufacturer, Qt::CaseInsensitive) == 0; });

            return (ddf.modelIds.contains(modelId) && (m != ddf.manufacturerNames.cend() || ddf.manufacturerNames.contains(manufacturerConstant)));
        });

        if (i == d->descriptions.end())
        {
            break;
        }

        if (!i->matchExpr.isEmpty() && match == DDF_EvalMatchExpr)
        {
            DeviceJs *djs = DeviceJs::instance();
            djs->reset();
            djs->setResource(resource->parentResource() ? resource->parentResource() : resource);
            if (djs->evaluate(i->matchExpr) == JsEvalResult::Ok)
            {
                const auto res = djs->result();
                DBG_Printf(DBG_DDF, "matchexpr: %s --> %s\n", qPrintable(i->matchExpr), qPrintable(res.toString()));
                if (res.toBool()) // needs to evaluate to true
                {
                    return *i;
                }
            }
            else
            {
                DBG_Printf(DBG_DDF, "failed to evaluate matchexpr for %s: %s, err: %s\n", qPrintable(resource->item(RAttrUniqueId)->toString()), qPrintable(i->matchExpr), qPrintable(djs->errorString()));
            }
            i++; // proceed search
        }
        else
        {
            return *i;
        }
    }

    return d->invalidDescription;
}

void DeviceDescriptions::put(const DeviceDescription &ddf)
{
    if (!ddf.isValid())
    {
        return;
    }

    Q_D(DeviceDescriptions);

    if (ddf.handle >= 0 && ddf.handle <= int(d->descriptions.size()))
    {
        DeviceDescription &ddf0 = d->descriptions[ddf.handle];

        DBG_Assert(ddf0.handle == ddf.handle);
        if (ddf.handle == ddf0.handle)
        {
            DBG_Printf(DBG_DDF, "update ddf %s index %d\n", qPrintable(ddf0.modelIds.front()), ddf.handle);
            ddf0 = ddf;
            DDF_UpdateItemHandles(d->descriptions, d->loadCounter);
            return;
        }
    }
}

const DeviceDescription &DeviceDescriptions::load(const QString &path)
{
    Q_D(DeviceDescriptions);

    auto i = std::find_if(d->descriptions.begin(), d->descriptions.end(), [&path](const auto &ddf){ return ddf.path == path; });
    if (i != d->descriptions.end())
    {
        return *i;
    }

    auto result = DDF_ReadDeviceFile(path);

    if (!result.empty())
    {
        for (auto &ddf : result)
        {
            ddf = DDF_MergeGenericItems(d->genericItems, ddf);
            ddf = DDF_LoadScripts(ddf);

            i = std::find_if(d->descriptions.begin(), d->descriptions.end(), [&ddf](const DeviceDescription &b)
            {
                return ddf.modelIds == b.modelIds && ddf.manufacturerNames == b.manufacturerNames;
            });

            if (i != d->descriptions.end())
            {
                *i = ddf; // update
            }
            else
            {
                d->descriptions.push_back(ddf);
            }
        }

        DDF_UpdateItemHandles(d->descriptions, d->loadCounter);

        i = std::find_if(d->descriptions.begin(), d->descriptions.end(), [&path](const auto &ddf){ return ddf.path == path; });
        if (i != d->descriptions.end())
        {
            return *i;
        }
    }

    return d->invalidDescription;
}

/*! Returns the DDF sub device belonging to a resource. */
const DeviceDescription::SubDevice &DeviceDescriptions::getSubDevice(const Resource *resource) const
{
    Q_D(const DeviceDescriptions);

    if (resource)
    {
        ItemHandlePack h;
        for (int i = 0; i < resource->itemCount(); i++)
        {
            const ResourceItem *item = resource->itemForIndex(size_t(i));
            assert(item);

            h.handle = item->ddfItemHandle();
            if (h.handle == DeviceDescription::Item::InvalidItemHandle)
            {
                continue;
            }

            if (h.loadCounter != d->loadCounter)
            {
                return d->invalidSubDevice;
            }

            DBG_Assert(h.description < d->descriptions.size());
            if (h.description >= d->descriptions.size())
            {
                return d->invalidSubDevice;
            }

            auto &ddf = d->descriptions[h.description];

            DBG_Assert(h.subDevice < ddf.subDevices.size());
            if (h.subDevice >= ddf.subDevices.size())
            {
                return d->invalidSubDevice;
            }

            return ddf.subDevices[h.subDevice];
        }
    }

    return d->invalidSubDevice;
}

/*! Turns a string constant into it's value.
    \returns The constant value on success, or the constant itself on error.
 */
QString DeviceDescriptions::constantToString(const QString &constant) const
{
    Q_D(const DeviceDescriptions);

    if (constant.startsWith('$'))
    {
        const auto i = d->constants.find(constant);

        if (i != d->constants.end())
        {
            return i->second;
        }
    }

    return constant;
}

QString DeviceDescriptions::stringToConstant(const QString &str) const
{
    Q_D(const DeviceDescriptions);

    if (str.startsWith('$'))
    {
        return str;
    }

    const auto end = d->constants.cend();
    for (auto p = d->constants.begin(); p != end; ++p)
    {
        if (p->second == str)
        {
            return p->first;
        }
    }

    return str;
}

QStringList DeviceDescriptions::constants(const QString &prefix) const
{
    Q_D(const DeviceDescriptions);
    QStringList result;

    const auto end = d->constants.cend();
    for (auto p = d->constants.begin(); p != end; ++p)
    {
        if (prefix.isEmpty() || p->first.startsWith(prefix))
        {
            result.push_back(p->first);
        }
    }

    return result;
}

static DeviceDescription::Item *DDF_GetItemMutable(const ResourceItem *item)
{
    if (!_priv || !item)
    {
        return nullptr;
    }

    DeviceDescriptionsPrivate *d = _priv;

    ItemHandlePack h;
    h.handle = item->ddfItemHandle(); // unpack

    if (h.handle == DeviceDescription::Item::InvalidItemHandle)
    {
        return nullptr;
    }

    if (h.loadCounter != d->loadCounter)
    {
        return nullptr;
    }

    DBG_Assert(h.description < d->descriptions.size());
    if (h.description >= d->descriptions.size())
    {
        return nullptr;
    }

    auto &ddf = d->descriptions[h.description];

    DBG_Assert(h.subDevice < ddf.subDevices.size());
    if (h.subDevice >= ddf.subDevices.size())
    {
        return nullptr;
    }

    auto &sub = ddf.subDevices[h.subDevice];

    DBG_Assert(h.item < sub.items.size());

    if (h.item < sub.items.size())
    {
        return &sub.items[h.item];
    }

    return nullptr;
}

/*! Retrieves the DDF item for the given \p item.

    If \p item has a valid DDF item handle the respective entry is returned.
    Otherwise the generic item list is searched based on the item.suffix.

    The returned entry can be check with DeviceDescription::Item::isValid().
 */
const DeviceDescription::Item &DDF_GetItem(const ResourceItem *item)
{
    Q_ASSERT(_instance);
    return _instance->getItem(item);
}

/*! \see DDF_GetItem() description.
 */
const DeviceDescription::Item &DeviceDescriptions::getItem(const ResourceItem *item) const
{
    Q_D(const DeviceDescriptions);

    ItemHandlePack h;
    h.handle = item->ddfItemHandle(); // unpack

    if (h.handle == DeviceDescription::Item::InvalidItemHandle)
    {
        return getGenericItem(item->descriptor().suffix);
    }

    if (h.loadCounter != d->loadCounter)
    {
        return d->invalidItem;
    }

    // Note: There are no further if conditions since at this point it's certain that a handle must be valid.

    Q_ASSERT(h.description < d->descriptions.size());

    const auto &ddf = d->descriptions[h.description];

    Q_ASSERT(h.subDevice < ddf.subDevices.size());

    const auto &sub = ddf.subDevices[h.subDevice];

    Q_ASSERT(h.item < sub.items.size());

    return sub.items[h.item];
}

const DDF_Items &DeviceDescriptions::genericItems() const
{
    return d_ptr2->genericItems;
}

const DeviceDescription::Item &DeviceDescriptions::getGenericItem(const char *suffix) const
{
    Q_D(const DeviceDescriptions);

    for (const auto &item : d->genericItems)
    {
        if (item.name == QLatin1String(suffix))
        {
            return item;
        }
    }

    return d->invalidItem;
}

const std::vector<DDF_FunctionDescriptor> &DeviceDescriptions::getParseFunctions() const
{
    return d_ptr2->parseFunctions;
}

const std::vector<DDF_FunctionDescriptor> &DeviceDescriptions::getReadFunctions() const
{
    return d_ptr2->readFunctions;
}

const std::vector<DDF_SubDeviceDescriptor> &DeviceDescriptions::getSubDevices() const
{
    return d_ptr2->subDevices;
}

/*! Updates all DDF item handles to point to correct location.
    \p loadCounter - the current load counter.
 */
static void DDF_UpdateItemHandles(std::vector<DeviceDescription> &descriptions, uint loadCounter)
{
    int index = 0;
    Q_ASSERT(loadCounter >= HND_MIN_LOAD_COUNTER);
    Q_ASSERT(loadCounter <= HND_MAX_LOAD_COUNTER);

    ItemHandlePack handle;
    handle.description = 0;
    handle.loadCounter = loadCounter;

    for (auto &ddf : descriptions)
    {
        ddf.handle = index++;
        handle.subDevice = 0;
        for (auto &sub : ddf.subDevices)
        {
            handle.item = 0;

            for (auto &item : sub.items)
            {
                item.handle = handle.handle;
                Q_ASSERT(handle.item < HND_MAX_ITEMS);
                handle.item++;
            }

            Q_ASSERT(handle.subDevice < HND_MAX_SUB_DEVS);
            handle.subDevice++;
        }

        Q_ASSERT(handle.description < HND_MAX_DESCRIPTIONS);
        handle.description++;
    }
}

/*! Reads all DDF related files.
 */
void DeviceDescriptions::readAll()
{
    Q_D(DeviceDescriptions);

    d->loadCounter = (d->loadCounter + 1) % HND_MAX_LOAD_COUNTER;
    if (d->loadCounter <= HND_MIN_LOAD_COUNTER)
    {
        d->loadCounter = HND_MIN_LOAD_COUNTER;
    }

    DBG_MEASURE_START(DDF_ReadAllFiles);

    std::vector<DeviceDescription> descriptions;
    std::vector<DeviceDescription::Item> genericItems;
    std::vector<DDF_SubDeviceDescriptor> subDevices;

    QStringList dirs;
    dirs.push_back(deCONZ::getStorageLocation(deCONZ::DdfUserLocation));
    dirs.push_back(deCONZ::getStorageLocation(deCONZ::DdfLocation));

    while (!dirs.isEmpty())
    {
        QDirIterator it(dirs.takeFirst(), QDirIterator::Subdirectories | QDirIterator::FollowSymlinks);

        while (it.hasNext())
        {
            it.next();

            if (it.filePath().endsWith(QLatin1String("generic/constants.json")))
            {
                std::map<QString,QString> constants;
                if (DDF_ReadConstantsJson(it.filePath(), &constants))
                {
                    d->constants = constants;
                }
            }
            else if (it.fileName() == QLatin1String("button_maps.json"))
            {  }
            else if (it.fileName().endsWith(QLatin1String(".json")))
            {
                if (it.filePath().contains(QLatin1String("generic/items/")))
                {
                    auto result = DDF_ReadItemFile(it.filePath());
                    if (result.isValid())
                    {
                        result.isGenericRead = !result.readParameters.isNull() ? 1 : 0;
                        result.isGenericWrite = !result.writeParameters.isNull() ? 1 : 0;
                        result.isGenericParse = !result.parseParameters.isNull() ? 1 : 0;
                        genericItems.push_back(std::move(result));
                    }
                }
                else if (it.filePath().contains(QLatin1String("generic/subdevices/")))
                {
                    auto sub = DDF_ReadSubDeviceFile(it.filePath());
                    if (isValid(sub))
                    {
                        subDevices.push_back(sub);
                    }
                }
                else
                {
                    DBG_Printf(DBG_DDF, "read %s\n", qPrintable(it.fileName()));
                    std::vector<DeviceDescription> result = DDF_ReadDeviceFile(it.filePath());
                    std::move(result.begin(), result.end(), std::back_inserter(descriptions));
                }
            }
        }
    }

    if (!genericItems.empty())
    {
        d->genericItems = std::move(genericItems);
    }

    if (!subDevices.empty())
    {
        std::sort(subDevices.begin(), subDevices.end(), [](const auto &a, const auto &b){
            return a.name < b.name;
        });

        d->subDevices = std::move(subDevices);
    }

    if (!descriptions.empty())
    {
        d->descriptions = std::move(descriptions);
        DDF_UpdateItemHandles(d->descriptions, d->loadCounter);

        for (auto &ddf : d->descriptions)
        {
            ddf = DDF_MergeGenericItems(d->genericItems, ddf);
            ddf = DDF_LoadScripts(ddf);
        }
    }

    DBG_MEASURE_END(DDF_ReadAllFiles);
}

/*! Tries to init a Device from an DDF file.

    Currently this is done syncronously later on it will be async to not block
    the main thread while loading DDF files.
 */
void DeviceDescriptions::handleDDFInitRequest(const Event &event)
{
    Q_D(DeviceDescriptions);

    auto *resource = DEV_GetResource(RDevices, QString::number(event.deviceKey()));

    int result = -1; // error

    if (resource)
    {
        const auto ddf = get(resource);

        if (ddf.isValid())
        {
            result = 0;

            if (!DEV_TestManaged() && !DDF_IsStatusEnabled(ddf.status))
            {
                result = 2;
            }
            else if (DEV_InitDeviceFromDescription(static_cast<Device*>(resource), ddf))
            {
                result = 1; // ok

                if (ddf.status == QLatin1String("Draft"))
                {
                    result = 2;
                }
            }
        }

        if (result >= 0)
        {
            DBG_Printf(DBG_INFO, "DEV found DDF for 0x%016llX, path: %s\n", event.deviceKey(), qPrintable(ddf.path));
        }

        if (result == 0)
        {
            DBG_Printf(DBG_INFO, "DEV init Device from DDF for 0x%016llX failed\n", event.deviceKey());
        }
        else if (result == -1)
        {
            DBG_Printf(DBG_INFO, "DEV no DDF for 0x%016llX, modelId: %s\n", event.deviceKey(), qPrintable(resource->item(RAttrModelId)->toString()));
            DBG_Printf(DBG_INFO, "DEV create on-the-fly DDF for 0x%016llX\n", event.deviceKey());

            DeviceDescription ddf1;

            Device *device = static_cast<Device*>(resource);

            if (DEV_InitBaseDescriptionForDevice(device, ddf1))
            {
                d->descriptions.push_back(ddf1);
                DDF_UpdateItemHandles(d->descriptions, d->loadCounter);
            }
        }
    }

    emit eventNotify(Event(RDevices, REventDDFInitResponse, result, event.deviceKey()));
}

/*! Reads constants.json file and places them into \p constants map.
 */
static bool DDF_ReadConstantsJson(const QString &path, std::map<QString,QString> *constants)
{
    Q_ASSERT(constants);

    QFile file(path);

    if (!file.exists())
    {
        return false;
    }

    if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
    {
        return false;
    }

    QJsonParseError error;
    QJsonDocument doc = QJsonDocument::fromJson(file.readAll(), &error);
    file.close();

    if (!doc.isObject())
    {
        DBG_Printf(DBG_INFO, "DDF failed to read device constants: %s, err: %s, offset: %d\n", qPrintable(path), qPrintable(error.errorString()), error.offset);
        return false;
    }

    const auto obj = doc.object();
    const QStringList categories {"manufacturers", "device-types"};

    for (const auto &cat : categories)
    {
        if (obj.contains(cat))
        {
            const auto catobj = obj.value(cat).toObject();
            for (auto &key : catobj.keys())
            {
                (*constants)[key] = catobj.value(key).toString();
            }
        }
    }

    return !constants->empty();
}

/*! Parses an item object.
    \returns A parsed item, use DeviceDescription::Item::isValid() to check for success.
 */
static DeviceDescription::Item DDF_ParseItem(const QJsonObject &obj)
{
    DeviceDescription::Item result;

    if (obj.contains(QLatin1String("name")))
    {
        result.name = obj.value(QLatin1String("name")).toString().toUtf8().constData();
    }
    else if (obj.contains(QLatin1String("id"))) // generic/item TODO align name/id?
    {
        result.name = obj.value(QLatin1String("id")).toString().toUtf8().constData();
    }

    if (obj.contains(QLatin1String("description")))
    {
        result.description = obj.value(QLatin1String("description")).toString();
    }

    if (result.name.empty())
    {

    }
    else if (getResourceItemDescriptor(result.name, result.descriptor))
    {
        if (obj.contains(QLatin1String("access")))
        {
            const auto access = obj.value(QLatin1String("access")).toString();
            if (access == "R")
            {
                result.descriptor.access = ResourceItemDescriptor::Access::ReadOnly;
            }
            else if (access == "RW")
            {
                result.descriptor.access = ResourceItemDescriptor::Access::ReadWrite;
            }
        }

        if (obj.contains(QLatin1String("public")))
        {
            result.isPublic = obj.value(QLatin1String("public")).toBool() ? 1 : 0;
            result.hasIsPublic = 1;
        }

        if (obj.contains(QLatin1String("implicit")))
        {
            result.isImplicit = obj.value(QLatin1String("implicit")).toBool() ? 1 : 0;
        }

        if (obj.contains(QLatin1String("awake")))
        {
            result.awake = obj.value(QLatin1String("awake")).toBool() ? 1 : 0;
        }

        if (obj.contains(QLatin1String("managed")))
        {
            result.isManaged = obj.value(QLatin1String("managed")).toBool() ? 1 : 0;
        }

        if (obj.contains(QLatin1String("refresh.interval")))
        {
            result.refreshInterval = obj.value(QLatin1String("refresh.interval")).toInt(0);
        }

        const auto parse = obj.value(QLatin1String("parse"));
        if (parse.isObject())
        {
            result.parseParameters = parse.toVariant();
        }

        const auto read = obj.value(QLatin1String("read"));
        if (read.isObject())
        {
            result.readParameters = read.toVariant();
        }

        const auto write = obj.value(QLatin1String("write"));
        if (write.isObject())
        {
            result.writeParameters = write.toVariant();
        }

        if (obj.contains(QLatin1String("static")))
        {
            result.isStatic = 1;
            result.defaultValue = obj.value(QLatin1String("static")).toVariant();
        }

        if (obj.contains(QLatin1String("default")))
        {
            result.defaultValue = obj.value(QLatin1String("default")).toVariant();
        }

        DBG_Printf(DBG_DDF, "DDF loaded resource item descriptor: %s, public: %u\n", result.descriptor.suffix, (result.isPublic ? 1 : 0));
    }
    else
    {
        DBG_Printf(DBG_DDF, "DDF failed to load resource item descriptor: %s\n", result.name.c_str());
    }

    return result;
}

/*! Parses a sub device in a DDF object "subdevices" array.
    \returns The sub device object, use DeviceDescription::SubDevice::isValid() to check for success.
 */
static DeviceDescription::SubDevice DDF_ParseSubDevice(const QJsonObject &obj)
{
    DeviceDescription::SubDevice result;

    result.type = obj.value(QLatin1String("type")).toString();
    if (result.type.isEmpty())
    {
        return result;
    }

    result.restApi = obj.value(QLatin1String("restapi")).toString();
    if (result.restApi.isEmpty())
    {
        return result;
    }

    if (obj.contains(QLatin1String("meta")))
    {
        auto meta = obj.value(QLatin1String("meta"));
        if (meta.isObject())
        {
            result.meta = meta.toVariant().toMap();
        }
    }

    const auto uniqueId = obj.value(QLatin1String("uuid"));
    if (uniqueId.isArray())
    {
        const auto arr = uniqueId.toArray();
        for (const auto &i : arr)
        {
            result.uniqueId.push_back(i.toString());
        }
    }

    const auto fingerPrint = obj.value(QLatin1String("fingerprint"));
    if (fingerPrint.isObject())
    {
        bool ok;
        const auto fp = fingerPrint.toObject();
        result.fingerPrint.endpoint = fp.value(QLatin1String("endpoint")).toString().toUInt(&ok, 0);
        result.fingerPrint.profileId = ok ? fp.value(QLatin1String("profile")).toString().toUInt(&ok, 0) : 0;
        result.fingerPrint.deviceId = ok ? fp.value(QLatin1String("device")).toString().toUInt(&ok, 0) : 0;

        if (fp.value(QLatin1String("in")).isArray())
        {
            const auto arr = fp.value(QLatin1String("in")).toArray();
            for (const auto &cl : arr)
            {
                const auto clusterId = ok ? cl.toString().toUInt(&ok, 0) : 0;
                if (ok)
                {
                    result.fingerPrint.inClusters.push_back(clusterId);
                }
            }
        }

        if (fp.value(QLatin1String("out")).isArray())
        {
            const auto arr = fp.value(QLatin1String("out")).toArray();
            for (const auto &cl : arr)
            {
                const auto clusterId = ok ? cl.toString().toUInt(&ok, 0) : 0;
                if (ok)
                {
                    result.fingerPrint.outClusters.push_back(clusterId);
                }
            }
        }

        if (!ok)
        {
            result.fingerPrint = { };
        }
    }

    const auto items = obj.value(QLatin1String("items"));
    if (!items.isArray())
    {
        return result;
    }

    {
        const auto arr = items.toArray();
        for (const auto &i : arr)
        {
            if (i.isObject())
            {
                const auto item = DDF_ParseItem(i.toObject());

                if (item.isValid())
                {
                    result.items.push_back(item);
                }
                else
                {

                }
            }
        }
    }

    return result;
}

// {"at": "0x0021", "dt": "u8", "min": 5, "max": 3600, "change": 1 },

/*! Parses a ZCL report in a DDF_Binding object "report" array.
    \returns The ZCL report, use DDF_ZclReport::isValid() to check for success.
 */
static DDF_ZclReport DDF_ParseZclReport(const QJsonObject &obj)
{
    DDF_ZclReport result{};

    // check required fields
    if (!obj.contains(QLatin1String("at")) ||
        !obj.contains(QLatin1String("dt")) ||
        !obj.contains(QLatin1String("min")) ||
        !obj.contains(QLatin1String("max")))
    {
        return {};
    }

    bool ok = false;
    result.attributeId = obj.value(QLatin1String("at")).toString().toUShort(&ok, 0);

    if (!ok)
    {
        return {};
    }

    {
        auto dataType = obj.value(QLatin1String("dt")).toString().toUShort(&ok, 0);
        if (!ok || dataType > 0xFF)
        {
            return {};
        }
        result.dataType = dataType;
    }

    {
        const auto minInterval = obj.value(QLatin1String("min")).toInt(-1);

        if (minInterval < 0 || minInterval > UINT16_MAX)
        {
            return {};
        }

        result.minInterval = minInterval;
    }

    {
        const auto maxInterval = obj.value(QLatin1String("max")).toInt(-1);

        if (maxInterval < 0 || maxInterval > UINT16_MAX)
        {
            return {};
        }

        result.maxInterval = maxInterval;
    }

    if (obj.contains(QLatin1String("change")))
    {
        result.reportableChange = obj.value(QLatin1String("change")).toString().toUInt(&ok, 0);

        if (!ok)
        {
            return {};
        }
    }

    if (obj.contains(QLatin1String("mf")))
    {
        result.manufacturerCode = obj.value(QLatin1String("mf")).toString().toUShort(&ok, 0);

        if (!ok)
        {
            return {};
        }
    }

    result.valid = true;

    return result;
}

/*! Parses a binding in a DDF object "bindings" array.
    \returns The binding, use DDF_Binding::isValid() to check for success.
 */
static DDF_Binding DDF_ParseBinding(const QJsonObject &obj)
{
    DDF_Binding result{};

    // check required fields
    if (!obj.contains(QLatin1String("bind")) ||
        !obj.contains(QLatin1String("src.ep")) ||
        !obj.contains(QLatin1String("cl")))
    {
        return {};
    }

    const auto type = obj.value(QLatin1String("bind")).toString();

    if (type == QLatin1String("unicast"))
    {
        result.isUnicastBinding = 1;
    }
    else if (type == QLatin1String("groupcast"))
    {
        result.isGroupBinding = 1;
    }
    else
    {
        return {};
    }

    bool ok = false;
    {
        const auto srcEndpoint = obj.value(QLatin1String("src.ep")).toInt(-1);

        if (srcEndpoint < 0 || srcEndpoint > UINT8_MAX)
        {
            return {};
        }
        result.srcEndpoint = srcEndpoint;
    }

    {
        result.clusterId = obj.value(QLatin1String("cl")).toString().toUShort(&ok, 0);

        if (!ok)
        {
            return {};
        }
    }

    if (obj.contains(QLatin1String("dst.ep")))
    {
        const auto dstEndpoint = obj.value(QLatin1String("dst.ep")).toInt(-1);
        if (dstEndpoint < 0 || dstEndpoint >= 255)
        {
            return {};
        }
        result.dstEndpoint = dstEndpoint;
    }
    else
    {
        result.dstEndpoint = 0;
    }

    if (result.isGroupBinding && obj.contains(QLatin1String("config.group")))
    {
        const auto configGroup = obj.value(QLatin1String("config.group")).toInt(-1);
        if (configGroup < 0 || configGroup >= 255)
        {
            return {};
        }
        result.configGroup = configGroup;
    }
    else
    {
        result.configGroup = 0;
    }

    const auto report = obj.value(QLatin1String("report"));
    if (report.isArray())
    {
        const auto reportArr = report.toArray();
        for (const auto &i : reportArr)
        {
            if (i.isObject())
            {
                const auto rep = DDF_ParseZclReport(i.toObject());
                if (isValid(rep))
                {
                    result.reporting.push_back(rep);
                }
            }
        }
    }

    return result;
}

/*! Parses a single string or array of strings in DDF JSON object.
    The obj[key] value can be a string or array of strings.
    \returns List of parsed strings.
 */
static QStringList DDF_ParseStringOrList(const QJsonObject &obj, QLatin1String key)
{
    QStringList result;
    const auto val = obj.value(key);

    if (val.isString()) // "key": "alpha.sensor"
    {
        result.push_back(val.toString());
    }
    else if (val.isArray()) // "key": [ "alpha.sensor", "beta.sensor" ]
    {
        const auto arr = val.toArray();
        for (const auto &i : arr)
        {
            if (i.isString())
            {
                result.push_back(i.toString());
            }
        }
    }

    return result;
}

/*! Parses an DDF JSON object.
    \returns DDF object, use DeviceDescription::isValid() to check for success.
 */
static DeviceDescription DDF_ParseDeviceObject(const QJsonObject &obj, const QString &path)
{
    DeviceDescription result;

    const auto schema = obj.value(QLatin1String("schema")).toString();

    if (schema != QLatin1String("devcap1.schema.json"))
    {
        return result;
    }

    const auto subDevices = obj.value(QLatin1String("subdevices"));
    if (!subDevices.isArray())
    {
        return result;
    }

    result.path = path;
    result.manufacturerNames = DDF_ParseStringOrList(obj, QLatin1String("manufacturername"));
    result.modelIds = DDF_ParseStringOrList(obj, QLatin1String("modelid"));
    result.product = obj.value(QLatin1String("product")).toString();

    if (obj.contains(QLatin1String("status")))
    {
        result.status = obj.value(QLatin1String("status")).toString();
    }

    if (obj.contains(QLatin1String("vendor")))
    {
        result.vendor = obj.value(QLatin1String("vendor")).toString();
    }

    if (obj.contains(QLatin1String("sleeper")))
    {
        result.sleeper = obj.value(QLatin1String("sleeper")).toBool() ? 1 : 0;
    }

    if (obj.contains(QLatin1String("matchexpr")))
    {
        result.matchExpr = obj.value(QLatin1String("matchexpr")).toString();
    }

    const auto keys = obj.keys();
    for (const auto &key : keys)
    {
        DBG_Printf(DBG_DDF, "DDF %s: %s\n", qPrintable(key), qPrintable(obj.value(key).toString()));
    }

    const auto subDevicesArr = subDevices.toArray();
    for (const auto &i : subDevicesArr)
    {
        if (i.isObject())
        {
            const auto sub = DDF_ParseSubDevice(i.toObject());
            if (sub.isValid())
            {
                result.subDevices.push_back(sub);
            }
        }
    }

    const auto bindings = obj.value(QLatin1String("bindings"));
    if (bindings.isArray())
    {
        const auto bindingsArr = bindings.toArray();
        for (const auto &i : bindingsArr)
        {
            if (i.isObject())
            {
                const auto bnd = DDF_ParseBinding(i.toObject());
                if (isValid(bnd))
                {
                    result.bindings.push_back(bnd);
                }
            }
        }
    }

    return result;
}

/*! Reads an item file under (generic/items/).
    \returns A parsed item, use DeviceDescription::Item::isValid() to check for success.
 */
static DeviceDescription::Item DDF_ReadItemFile(const QString &path)
{
    QFile file(path);
    if (!file.exists())
    {
        return { };
    }

    if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
    {
        return { };
    }

    QJsonParseError error;
    QJsonDocument doc = QJsonDocument::fromJson(file.readAll(), &error);
    file.close();

    if (error.error != QJsonParseError::NoError)
    {
        DBG_Printf(DBG_DDF, "DDF failed to read %s, err: %s, offset: %d\n", qPrintable(path), qPrintable(error.errorString()), error.offset);
        return { };
    }

    if (doc.isObject())
    {
        return DDF_ParseItem(doc.object());
    }

    return { };
}

/*! Reads an subdevice file under (generic/subdevices/).
    \returns A parsed subdevice, use isValid(DDF_SubDeviceDescriptor) to check for success.
 */
static DDF_SubDeviceDescriptor DDF_ReadSubDeviceFile(const QString &path)
{
    DDF_SubDeviceDescriptor result;

    QFile file(path);
    if (!file.exists())
    {
        return result;
    }

    if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
    {
        return result;
    }

    QJsonParseError error;
    QJsonDocument doc = QJsonDocument::fromJson(file.readAll(), &error);
    file.close();

    if (error.error != QJsonParseError::NoError)
    {
        DBG_Printf(DBG_DDF, "DDF failed to read %s, err: %s, offset: %d\n", qPrintable(path), qPrintable(error.errorString()), error.offset);
        return result;
    }

    if (doc.isObject())
    {
        const auto obj = doc.object();
        QString schema;
        if (obj.contains(QLatin1String("schema")))
        {
            schema = obj.value(QLatin1String("schema")).toString();
        }

        if (schema != QLatin1String("subdevice1.schema.json"))
        {
            return result;
        }

        if (obj.contains(QLatin1String("name")))
        {
            result.name = obj.value(QLatin1String("name")).toString();
        }
        if (obj.contains(QLatin1String("type")))
        {
            result.type = obj.value(QLatin1String("type")).toString();
        }
        if (obj.contains(QLatin1String("restapi")))
        {
            result.restApi = obj.value(QLatin1String("restapi")).toString();
        }

        result.order = obj.value(QLatin1String("order")).toInt(SUBDEVICE_DEFAULT_ORDER);

        if (obj.contains(QLatin1String("uuid")))
        {
            const auto uniqueId = obj.value(QLatin1String("uuid"));
            if (uniqueId.isArray())
            {
                const auto arr = uniqueId.toArray();
                for (const auto &i : arr)
                {
                    DBG_Assert(i.isString());
                    result.uniqueId.push_back(i.toString());
                }
            }
        }
        if (obj.contains(QLatin1String("items")))
        {
            const auto items = obj.value(QLatin1String("items"));
            if (items.isArray())
            {
                const auto arr = items.toArray();
                for (const auto &i : arr)
                {
                    DBG_Assert(i.isString());
                    ResourceItemDescriptor rid;
                    if (getResourceItemDescriptor(i.toString(), rid))
                    {
                        result.items.push_back(rid.suffix);
                    }
                }
            }
        }
    }

    return result;
}

QVariant DDF_ResolveParamScript(const QVariant &param, const QString &path)
{
    auto result = param;

    if (param.type() != QVariant::Map)
    {
        return result;
    }

    auto map = param.toMap();

    if (map.contains("script"))
    {
        const auto script = map["script"].toString();

        const QFileInfo fi(path);
        QFile f(fi.canonicalPath() + "/" + script);

        if (f.exists() && f.open(QFile::ReadOnly))
        {
            const auto content = f.readAll();
            if (!content.isEmpty())
            {
                map["eval"] = content;
                result = std::move(map);
            }
        }
    }

    return result;
}

DeviceDescription DDF_LoadScripts(const DeviceDescription &ddf)
{
    auto result = ddf;

    for (auto &sub : result.subDevices)
    {
        for (auto &item : sub.items)
        {
            item.parseParameters = DDF_ResolveParamScript(item.parseParameters, ddf.path);
            item.readParameters = DDF_ResolveParamScript(item.readParameters, ddf.path);
            item.writeParameters = DDF_ResolveParamScript(item.writeParameters, ddf.path);
        }
    }

    return result;
}

/*! Reads a DDF file which may contain one or more device descriptions.
    \returns Vector of parsed DDF objects.
 */
static std::vector<DeviceDescription> DDF_ReadDeviceFile(const QString &path)
{
    std::vector<DeviceDescription> result;

    QFile file(path);
    if (!file.exists())
    {
        return result;
    }

    if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
    {
        return result;
    }

    QJsonParseError error;
    QJsonDocument doc = QJsonDocument::fromJson(file.readAll(), &error);
    file.close();

    if (error.error != QJsonParseError::NoError)
    {
        DBG_Printf(DBG_DDF, "DDF failed to read %s, err: %s, offset: %d\n", qPrintable(path), qPrintable(error.errorString()), error.offset);
        return result;
    }

    if (doc.isObject())
    {
        const auto ddf = DDF_ParseDeviceObject(doc.object(), path);
        if (ddf.isValid())
        {
            result.push_back(ddf);
        }
    }
    else if (doc.isArray())
    {
        const auto arr = doc.array();
        for (const auto &i : arr)
        {
            if (i.isObject())
            {
                const auto ddf = DDF_ParseDeviceObject(i.toObject(), path);
                if (ddf.isValid())
                {
                    result.push_back(ddf);
                }
            }
        }
    }

    return result;
}

/*! Merge common properties like "read", "parse" and "write" functions from generic items into DDF items.
    Only properties which are already defined in the DDF file won't be overwritten.

    \param genericItems - generic items used as source
    \param ddf - DDF object with unmerged items
    \returns The merged DDF object.
 */
static DeviceDescription DDF_MergeGenericItems(const std::vector<DeviceDescription::Item> &genericItems, const DeviceDescription &ddf)
{
    auto result = ddf;

    for (auto &sub : result.subDevices)
    {
        for (auto &item : sub.items)
        {
            const auto genItem = std::find_if(genericItems.cbegin(), genericItems.cend(),
                                              [&item](const DeviceDescription::Item &i){ return i.descriptor.suffix == item.descriptor.suffix; });
            if (genItem == genericItems.cend())
            {
                continue;
            }

            item.isImplicit = genItem->isImplicit;
            item.isManaged = genItem->isManaged;
            item.isGenericRead = 0;
            item.isGenericWrite = 0;
            item.isGenericParse = 0;

            if (item.readParameters.isNull()) { item.readParameters = genItem->readParameters; item.isGenericRead = 1; }
            if (item.writeParameters.isNull()) { item.writeParameters = genItem->writeParameters; item.isGenericWrite = 1; }
            if (item.parseParameters.isNull()) { item.parseParameters = genItem->parseParameters; item.isGenericParse = 1; }
            if (item.descriptor.access == ResourceItemDescriptor::Access::Unknown)
            {
                item.descriptor.access = genItem->descriptor.access;
            }
            if (!item.hasIsPublic)
            {
                item.isPublic = genItem->isPublic;
            }
            if (item.refreshInterval == DeviceDescription::Item::NoRefreshInterval && genItem->refreshInterval != item.refreshInterval)
            {
                item.refreshInterval = genItem->refreshInterval;
            }

            if (!item.defaultValue.isValid() && genItem->defaultValue.isValid())
            {
                item.defaultValue = genItem->defaultValue;
            }
        }
    }

    return result;
}

uint8_t DDF_GetSubDeviceOrder(const QString &type)
{
    if (type.isEmpty() || type.startsWith(QLatin1String("CLIP")))
    {
        return SUBDEVICE_DEFAULT_ORDER;
    }

    if (_priv)
    {
        auto i = std::find_if(_priv->subDevices.cbegin(), _priv->subDevices.cend(), [&](const auto &sub)
        { return sub.name == type; });

        if (i != _priv->subDevices.cend())
        {
            return i->order;
        }
    }

#ifdef QT_DEBUG
    DBG_Printf(DBG_DDF, "DDF No subdevice for type: %s\n", qPrintable(type));
#endif

    return SUBDEVICE_DEFAULT_ORDER;
}

/*! Creates a unique Resource handle.
 */
Resource::Handle R_CreateResourceHandle(const Resource *r, size_t containerIndex)
{
    Q_ASSERT(r->prefix() != nullptr);
    Q_ASSERT(!r->item(RAttrUniqueId)->toString().isEmpty());

    Resource::Handle result;
    result.hash = qHash(r->item(RAttrUniqueId)->toString());
    result.index = containerIndex;
    result.type = r->prefix()[1];
    result.order = 0;

    Q_ASSERT(result.type == 's' || result.type == 'l' || result.type == 'd' || result.type == 'g');
    Q_ASSERT(isValid(result));

    if (result.type == 's' || result.type == 'l')
    {
        const ResourceItem *type = r->item(RAttrType);
        if (type)
        {
            result.order = DDF_GetSubDeviceOrder(type->toString());
        }
    }

    return result;
}