// Copyright (C) 2020 Intel Corporation.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include "qcborvalue.h"
#include "qcborvalue_p.h"

#include "qcborarray.h"
#include "qcbormap.h"

#include "qjsonarray.h"
#include "qjsonobject.h"
#include "qjsondocument.h"
#include "qjson_p.h"

#include <qmap.h>
#include <qhash.h>

#include <private/qnumeric_p.h>
#include <quuid.h>

QT_BEGIN_NAMESPACE

using namespace QtCbor;

enum class ConversionMode { FromRaw, FromVariantToJson };

static QJsonValue fpToJson(double v)
{
    return qt_is_finite(v) ? QJsonValue(v) : QJsonValue();
}

static QString simpleTypeString(QCborValue::Type t)
{
    int simpleType = t - QCborValue::SimpleType;
    if (unsigned(simpleType) < 0x100)
        return QString::fromLatin1("simple(%1)").arg(simpleType);

    // if we got here, we got an unknown type
    qWarning("QCborValue: found unknown type 0x%x", t);
    return QString();

}

static QString encodeByteArray(const QCborContainerPrivate *d, qsizetype idx, QCborTag encoding)
{
    const ByteData *b = d->byteData(idx);
    if (!b)
        return QString();

    QByteArray data = QByteArray::fromRawData(b->byte(), b->len);
    if (encoding == QCborKnownTags::ExpectedBase16)
        data = data.toHex();
    else if (encoding == QCborKnownTags::ExpectedBase64)
        data = data.toBase64();
    else
        data = data.toBase64(QByteArray::Base64UrlEncoding | QByteArray::OmitTrailingEquals);

    return QString::fromLatin1(data, data.size());
}

static QString makeString(const QCborContainerPrivate *d, qsizetype idx,
                          ConversionMode mode = ConversionMode::FromRaw);

static QString maybeEncodeTag(const QCborContainerPrivate *d)
{
    qint64 tag = d->elements.at(0).value;
    const Element &e = d->elements.at(1);

    switch (tag) {
    case qint64(QCborKnownTags::DateTimeString):
    case qint64(QCborKnownTags::Url):
        if (e.type == QCborValue::String)
            return makeString(d, 1);
        break;

    case qint64(QCborKnownTags::ExpectedBase64url):
    case qint64(QCborKnownTags::ExpectedBase64):
    case qint64(QCborKnownTags::ExpectedBase16):
        if (e.type == QCborValue::ByteArray)
            return encodeByteArray(d, 1, QCborTag(tag));
        break;

    case qint64(QCborKnownTags::Uuid):
#ifndef QT_BOOTSTRAPPED
        if (const ByteData *b = d->byteData(e); e.type == QCborValue::ByteArray && b
                && b->len == sizeof(QUuid))
            return QUuid::fromRfc4122(b->asByteArrayView()).toString(QUuid::WithoutBraces);
#endif
        break;
    }

    // don't know what to do, bail out
    return QString();
}

static QString encodeTag(const QCborContainerPrivate *d)
{
    QString s;
    if (!d || d->elements.size() != 2)
        return s;               // invalid (incomplete?) tag state

    s = maybeEncodeTag(d);
    if (s.isNull()) {
        // conversion failed, ignore the tag and convert the tagged value
        s = makeString(d, 1);
    }
    return s;
}

static Q_NEVER_INLINE QString makeString(const QCborContainerPrivate *d, qsizetype idx,
                                         ConversionMode mode)
{
    const auto &e = d->elements.at(idx);

    switch (e.type) {
    case QCborValue::Integer:
        return QString::number(qint64(e.value));

    case QCborValue::Double:
        return QString::number(e.fpvalue());

    case QCborValue::ByteArray:
        return mode == ConversionMode::FromVariantToJson
                ? d->stringAt(idx)
                : encodeByteArray(d, idx, QCborTag(QCborKnownTags::ExpectedBase64url));

    case QCborValue::String:
        return d->stringAt(idx);

    case QCborValue::Array:
    case QCborValue::Map:
#if defined(QT_JSON_READONLY) || defined(QT_BOOTSTRAPPED)
        qFatal("Writing JSON is disabled.");
        return QString();
#else
        return d->valueAt(idx).toDiagnosticNotation(QCborValue::Compact);
#endif

    case QCborValue::SimpleType:
        break;

    case QCborValue::False:
        return QStringLiteral("false");

    case QCborValue::True:
        return QStringLiteral("true");

    case QCborValue::Null:
        return QStringLiteral("null");

    case QCborValue::Undefined:
        return QStringLiteral("undefined");

    case QCborValue::Invalid:
        return QString();

    case QCborValue::Tag:
    case QCborValue::DateTime:
    case QCborValue::Url:
    case QCborValue::RegularExpression:
    case QCborValue::Uuid:
        return encodeTag(e.flags & Element::IsContainer ? e.container : nullptr);
    }

    // maybe it's a simple type
    return simpleTypeString(e.type);
}

QJsonValue qt_convertToJson(QCborContainerPrivate *d, qsizetype idx,
                            ConversionMode mode = ConversionMode::FromRaw);

static QJsonValue convertExtendedTypeToJson(QCborContainerPrivate *d)
{
    qint64 tag = d->elements.at(0).value;

    switch (tag) {
    case qint64(QCborKnownTags::Url):
#ifdef QT_BOOTSTRAPPED
        break;
#else
        // use the fully-encoded URL form
        if (d->elements.at(1).type == QCborValue::String)
            return QUrl::fromEncoded(d->byteData(1)->asByteArrayView()).toString(QUrl::FullyEncoded);
        Q_FALLTHROUGH();
#endif

    case qint64(QCborKnownTags::DateTimeString):
    case qint64(QCborKnownTags::ExpectedBase64url):
    case qint64(QCborKnownTags::ExpectedBase64):
    case qint64(QCborKnownTags::ExpectedBase16):
    case qint64(QCborKnownTags::Uuid): {
        // use the string conversion
        QString s = maybeEncodeTag(d);
        if (!s.isNull())
            return s;
    }
    }

    // for all other tags, ignore it and return the converted tagged item
    return qt_convertToJson(d, 1);
}

// We need to do this because sub-objects may need conversion.
static QJsonArray convertToJsonArray(QCborContainerPrivate *d,
                                     ConversionMode mode = ConversionMode::FromRaw)
{
    QJsonArray a;
    if (d) {
        for (qsizetype idx = 0; idx < d->elements.size(); ++idx)
            a.append(qt_convertToJson(d, idx, mode));
    }
    return a;
}

// We need to do this because the keys need to be sorted and converted to strings
// and sub-objects may need recursive conversion.
static QJsonObject convertToJsonObject(QCborContainerPrivate *d,
                                       ConversionMode mode = ConversionMode::FromRaw)
{
    QJsonObject o;
    if (d) {
        for (qsizetype idx = 0; idx < d->elements.size(); idx += 2)
            o.insert(makeString(d, idx), qt_convertToJson(d, idx + 1, mode));
    }
    return o;
}

QJsonValue qt_convertToJson(QCborContainerPrivate *d, qsizetype idx, ConversionMode mode)
{
    // encoding the container itself
    if (idx == -QCborValue::Array)
        return convertToJsonArray(d, mode);
    if (idx == -QCborValue::Map)
        return convertToJsonObject(d, mode);
    if (idx < 0) {
        // tag-like type
        if (!d || d->elements.size() != 2)
            return QJsonValue::Undefined;   // invalid state
        return convertExtendedTypeToJson(d);
    }

    // an element in the container
    const auto &e = d->elements.at(idx);
    switch (e.type) {
    case QCborValue::Integer:
        return QJsonValue(e.value);
    case QCborValue::ByteArray:
        if (mode == ConversionMode::FromVariantToJson) {
            const auto value = makeString(d, idx, mode);
            return value.isEmpty() ? QJsonValue() : QJsonPrivate::Value::fromTrustedCbor(value);
        }
        break;
    case QCborValue::RegularExpression:
        if (mode == ConversionMode::FromVariantToJson)
            return QJsonValue();
        break;
    case QCborValue::String:
    case QCborValue::SimpleType:
        // make string
        break;

    case QCborValue::Array:
    case QCborValue::Map:
    case QCborValue::Tag:
    case QCborValue::DateTime:
    case QCborValue::Url:
    case QCborValue::Uuid:
        // recurse
        return qt_convertToJson(e.flags & Element::IsContainer ? e.container : nullptr, -e.type,
                                mode);

    case QCborValue::Null:
    case QCborValue::Undefined:
    case QCborValue::Invalid:
        return QJsonValue();

    case QCborValue::False:
        return false;

    case QCborValue::True:
        return true;

    case QCborValue::Double:
        return fpToJson(e.fpvalue());
    }

    return QJsonPrivate::Value::fromTrustedCbor(makeString(d, idx, mode));
}

/*!
    Converts this QCborValue object to an equivalent representation in JSON and
    returns it as a QJsonValue.

    Please note that CBOR contains a richer and wider type set than JSON, so
    some information may be lost in this conversion. The following table
    compares CBOR types to JSON types and indicates whether information may be
    lost or not.

    \table
      \header \li CBOR Type     \li JSON Type   \li Comments
      \row  \li Bool            \li Bool        \li No data loss possible
      \row  \li Double          \li Number      \li Infinities and NaN will be converted to Null;
                                                    no data loss for other values
      \row  \li Integer         \li Number      \li Data loss possible in the conversion if the
                                                    integer is larger than 2\sup{53} or smaller
                                                    than -2\sup{53}.
      \row  \li Null            \li Null        \li No data loss possible
      \row  \li Undefined       \li Null        \li Type information lost
      \row  \li String          \li String      \li No data loss possible
      \row  \li Byte Array      \li String      \li Converted to a lossless encoding like Base64url,
                                                    but the distinction between strings and byte
                                                    arrays is lost
      \row  \li Other simple types \li String   \li Type information lost
      \row  \li Array           \li Array       \li Conversion applies to each contained value
      \row  \li Map             \li Object      \li Keys are converted to string; values converted
                                                    according to this table
      \row  \li Tags and extended types \li Special \li The tag number itself is lost and the tagged
                                                    value is converted to JSON
    \endtable

    For information on the conversion of CBOR map keys to string, see
    QCborMap::toJsonObject().

    If this QCborValue contains the undefined value, this function will return
    an undefined QJsonValue too. Note that JSON does not support undefined
    values and undefined QJsonValues are an extension to the specification.
    They cannot be held in a QJsonArray or QJsonObject, but can be returned
    from functions to indicate a failure. For all other intents and purposes,
    they are the same as null.

    \section3 Special handling of tags and extended types

    Some tags are handled specially and change the transformation of the tagged
    value from CBOR to JSON. The following table lists those special cases:

    \table
      \header \li Tag           \li CBOR type       \li Transformation
      \row  \li ExpectedBase64url \li Byte array    \li Encodes the byte array as Base64url
      \row  \li ExpectedBase64  \li Byte array      \li Encodes the byte array as Base64
      \row  \li ExpectedBase16  \li Byte array      \li Encodes the byte array as hex
      \row  \li Url             \li Url and String  \li Uses QUrl::toEncoded() to normalize the
                                                    encoding to the URL's fully encoded format
      \row  \li Uuid            \li Uuid and Byte array \li Uses QUuid::toString() to create
                                                    the string representation
    \endtable

    \sa fromJsonValue(), toVariant(), QCborArray::toJsonArray(), QCborMap::toJsonObject()
 */
QJsonValue QCborValue::toJsonValue() const
{
    if (container)
        return qt_convertToJson(container, n < 0 ? -type() : n);

    // simple values
    switch (type()) {
    case False:
        return false;

    case Integer:
        return QJsonPrivate::Value::fromTrustedCbor(*this);

    case True:
        return true;

    case Null:
    case Undefined:
    case Invalid:
        return QJsonValue();

    case Double:
        return fpToJson(fp_helper());

    case SimpleType:
        break;

    case ByteArray:
    case String:
        // empty strings
        return QJsonValue::String;

    case Array:
        // empty array
        return QJsonArray();

    case Map:
        // empty map
        return QJsonObject();

    case Tag:
    case DateTime:
    case Url:
    case RegularExpression:
    case Uuid:
        // Reachable, but invalid in Json
        return QJsonValue::Undefined;
    }

    return QJsonPrivate::Value::fromTrustedCbor(simpleTypeString(type()));
}

#if QT_VERSION < QT_VERSION_CHECK(7, 0, 0) && !defined(QT_BOOTSTRAPPED)
QJsonValue QCborValueRef::toJsonValue() const
{
    return qt_convertToJson(d, i);
}
#endif

/*!
    Recursively converts every \l QCborValue element in this array to JSON
    using QCborValue::toJsonValue() and returns the corresponding QJsonArray
    composed of those elements.

    Please note that CBOR contains a richer and wider type set than JSON, so
    some information may be lost in this conversion. For more details on what
    conversions are applied, see QCborValue::toJsonValue().

    \sa fromJsonArray(), QCborValue::toJsonValue(), QCborMap::toJsonObject(), toVariantList()
 */
QJsonArray QCborArray::toJsonArray() const
{
    return convertToJsonArray(d.data());
}

QJsonArray QJsonPrivate::Variant::toJsonArray(const QVariantList &list)
{
    const auto cborArray = QCborArray::fromVariantList(list);
    return convertToJsonArray(cborArray.d.data(), ConversionMode::FromVariantToJson);
}

/*!
    Recursively converts every \l QCborValue value in this map to JSON using
    QCborValue::toJsonValue() and creates a string key for all keys that aren't
    strings, then returns the corresponding QJsonObject composed of those
    associations.

    Please note that CBOR contains a richer and wider type set than JSON, so
    some information may be lost in this conversion. For more details on what
    conversions are applied, see QCborValue::toJsonValue().

    \section3 Map key conversion to string

    JSON objects are defined as having string keys, unlike CBOR, so the
    conversion of a QCborMap to QJsonObject will imply a step of
    "stringification" of the key values. The conversion will use the special
    handling of tags and extended types from above and will also convert the
    rest of the types as follows:

    \table
      \header \li Type              \li Transformation
      \row  \li Bool                \li "true" and "false"
      \row  \li Null                \li "null"
      \row  \li Undefined           \li "undefined"
      \row  \li Integer             \li The decimal string form of the number
      \row  \li Double              \li The decimal string form of the number
      \row  \li Byte array          \li Unless tagged differently (see above), encoded as
                                        Base64url
      \row  \li Array               \li Replaced by the compact form of its
                                        \l{QCborValue::toDiagnosticNotation()}{Diagnostic notation}
      \row  \li Map                 \li Replaced by the compact form of its
                                        \l{QCborValue::toDiagnosticNotation()}{Diagnostic notation}
      \row  \li Tags and extended types \li Tag number is dropped and the tagged value is converted
                                        to string
    \endtable

    \sa fromJsonObject(), QCborValue::toJsonValue(), QCborArray::toJsonArray(), toVariantMap()
 */
QJsonObject QCborMap::toJsonObject() const
{
    return convertToJsonObject(d.data());
}

QJsonObject QJsonPrivate::Variant::toJsonObject(const QVariantMap &map)
{
    const auto cborMap = QCborMap::fromVariantMap(map);
    return convertToJsonObject(cborMap.d.data(), ConversionMode::FromVariantToJson);
}

/*!
    Converts this value to a native Qt type and returns the corresponding QVariant.

    The following table lists the mapping performed between \l{Type}{QCborValue
    types} and \l{QMetaType::Type}{Qt meta types}.

    \table
      \header \li CBOR Type         \li Qt or C++ type          \li Notes
      \row  \li Integer             \li \l qint64               \li
      \row  \li Double              \li \c double               \li
      \row  \li Bool                \li \c bool                 \li
      \row  \li Null                \li \c std::nullptr_t       \li
      \row  \li Undefined           \li no type (QVariant())    \li
      \row  \li Byte array          \li \l QByteArray           \li
      \row  \li String              \li \l QString              \li
      \row  \li Array               \li \l QVariantList         \li Recursively converts all values
      \row  \li Map                 \li \l QVariantMap          \li Key types are "stringified"
      \row  \li Other simple types  \li \l QCborSimpleType      \li
      \row  \li DateTime            \li \l QDateTime            \li
      \row  \li Url                 \li \l QUrl                 \li
      \row  \li RegularExpression   \li \l QRegularExpression   \li
      \row  \li Uuid                \li \l QUuid                \li
      \row  \li Other tags          \li Special                 \li The tag is ignored and the tagged
                                                                    value is converted using this
                                                                    function
    \endtable

    Note that values in both CBOR Maps and Arrays are converted recursively
    using this function too and placed in QVariantMap and QVariantList instead.
    You will not find QCborMap and QCborArray stored inside the QVariants.

    QVariantMaps have string keys, unlike CBOR, so the conversion of a QCborMap
    to QVariantMap will imply a step of "stringification" of the key values.
    See QCborMap::toJsonObject() for details.

    \sa fromVariant(), toJsonValue(), QCborArray::toVariantList(), QCborMap::toVariantMap()
 */
QVariant QCborValue::toVariant() const
{
    switch (type()) {
    case Integer:
        return toInteger();

    case Double:
        return toDouble();

    case SimpleType:
        break;

    case False:
    case True:
        return isTrue();

    case Null:
        return QVariant::fromValue(nullptr);

    case Undefined:
        return QVariant();

    case ByteArray:
        return toByteArray();

    case String:
        return toString();

    case Array:
        return toArray().toVariantList();

    case Map:
        return toMap().toVariantMap();

    case Tag:
        // ignore tags
        return taggedValue().toVariant();

    case DateTime:
        return toDateTime();

#ifndef QT_BOOTSTRAPPED
    case Url:
        return toUrl();

#  if QT_CONFIG(regularexpression)
    case RegularExpression:
        return toRegularExpression();
#  endif

    case Uuid:
        return toUuid();
#endif

    case Invalid:
        return QVariant();

    default:
        break;
    }

    if (isSimpleType())
        return QVariant::fromValue(toSimpleType());

    Q_UNREACHABLE_RETURN(QVariant());
}

/*!
    Converts the JSON value contained in \a v into its corresponding CBOR value
    and returns it. There is no data loss in converting from JSON to CBOR, as
    the CBOR type set is richer than JSON's. Additionally, values converted to
    CBOR using this function can be converted back to JSON using toJsonValue()
    with no data loss.

    The following table lists the mapping of JSON types to CBOR types:

    \table
      \header \li JSON Type     \li CBOR Type
      \row  \li Bool            \li Bool
      \row  \li Number          \li Integer (if the number has no fraction and is in the \l qint64
                                    range) or Double
      \row  \li String          \li String
      \row  \li Array           \li Array
      \row  \li Object          \li Map
      \row  \li Null            \li Null
    \endtable

    \l QJsonValue can also be undefined, indicating a previous operation that
    failed to complete (for example, searching for a key not present in an
    object). Undefined values are not JSON types and may not appear in JSON
    arrays and objects, but this function does return the QCborValue undefined
    value if the corresponding QJsonValue is undefined.

    \sa toJsonValue(), fromVariant(), QCborArray::fromJsonArray(), QCborMap::fromJsonObject()
 */
QCborValue QCborValue::fromJsonValue(const QJsonValue &v)
{
    switch (v.type()) {
    case QJsonValue::Bool:
        return v.toBool();
    case QJsonValue::Double: {
        if (v.value.t == Integer)
            return v.toInteger();
        return v.toDouble();
    }
    case QJsonValue::String:
        return v.toString();
    case QJsonValue::Array:
        return QCborArray::fromJsonArray(v.toArray());
    case QJsonValue::Object:
        return QCborMap::fromJsonObject(v.toObject());
    case QJsonValue::Null:
        return nullptr;
    case QJsonValue::Undefined:
        break;
    }
    return QCborValue();
}

static void appendVariant(QCborContainerPrivate *d, const QVariant &variant)
{
    // Handle strings and byte arrays directly, to avoid creating a temporary
    // dummy container to hold their data.
    int type = variant.metaType().id();
    if (type == QMetaType::QString) {
        d->append(variant.toString());
    } else if (type == QMetaType::QByteArray) {
        QByteArray ba = variant.toByteArray();
        d->appendByteData(ba.constData(), ba.size(), QCborValue::ByteArray);
    } else {
        // For everything else, use the function below.
        d->append(QCborValue::fromVariant(variant));
    }
}

/*!
    Converts the QVariant \a variant into QCborValue and returns it.

    QVariants may contain a large list of different meta types, many of which
    have no corresponding representation in CBOR. That includes all
    user-defined meta types. When preparing transmission using CBOR, it is
    suggested to encode carefully each value to prevent loss of representation.

    The following table lists the conversion this function will apply:

    \table
      \header \li Qt (C++) type             \li CBOR type
      \row  \li invalid (QVariant())        \li Undefined
      \row  \li \c bool                     \li Bool
      \row  \li \c std::nullptr_t           \li Null
      \row  \li \c short, \c ushort, \c int, \c uint, \l qint64  \li Integer
      \row  \li \l quint64                  \li Integer, or Double if outside the range of qint64
      \row  \li \c float, \c double         \li Double
      \row  \li \l QByteArray               \li ByteArray
      \row  \li \l QDateTime                \li DateTime
      \row  \li \l QCborSimpleType          \li Simple type
      \row  \li \l QJsonArray               \li Array, converted using QCborArray::formJsonArray()
      \row  \li \l QJsonDocument            \li Array or Map
      \row  \li \l QJsonObject              \li Map, converted using QCborMap::fromJsonObject()
      \row  \li \l QJsonValue               \li converted using fromJsonValue()
      \row  \li \l QRegularExpression       \li RegularExpression
      \row  \li \l QString                  \li String
      \row  \li \l QStringList              \li Array
      \row  \li \l QVariantHash             \li Map
      \row  \li \l QVariantList             \li Array
      \row  \li \l QVariantMap              \li Map
      \row  \li \l QUrl                     \li Url
      \row  \li \l QUuid                    \li Uuid
    \endtable

    If QVariant::isNull() returns true, a null QCborValue is returned or
    inserted into the list or object, regardless of the type carried by
    QVariant. Note the behavior change in Qt 6.0 affecting QVariant::isNull()
    also affects this function.

    For other types not listed above, a conversion to string will be attempted,
    usually but not always by calling QVariant::toString(). If the conversion
    fails the value is replaced by an Undefined CBOR value. Note that
    QVariant::toString() is also lossy for the majority of types.

    Please note that the conversions via QVariant::toString() are subject to
    change at any time. Both QVariant and QCborValue may be extended in the
    future to support more types, which will result in a change in how this
    function performs conversions.

    \sa toVariant(), fromJsonValue(), QCborArray::toVariantList(), QCborMap::toVariantMap(), QJsonValue::fromVariant()
 */
QCborValue QCborValue::fromVariant(const QVariant &variant)
{
    switch (variant.metaType().id()) {
    case QMetaType::UnknownType:
        return {};
    case QMetaType::Nullptr:
        return nullptr;
    case QMetaType::Bool:
        return variant.toBool();
    case QMetaType::Short:
    case QMetaType::UShort:
    case QMetaType::Int:
    case QMetaType::LongLong:
    case QMetaType::UInt:
        return variant.toLongLong();
    case QMetaType::ULongLong:
        if (variant.toULongLong() <= static_cast<uint64_t>(std::numeric_limits<qint64>::max()))
            return variant.toLongLong();
        Q_FALLTHROUGH();
    case QMetaType::Float:
    case QMetaType::Double:
        return variant.toDouble();
    case QMetaType::QString:
        return variant.toString();
    case QMetaType::QStringList:
        return QCborArray::fromStringList(variant.toStringList());
    case QMetaType::QByteArray:
        return variant.toByteArray();
    case QMetaType::QDateTime:
        return QCborValue(variant.toDateTime());
#ifndef QT_BOOTSTRAPPED
    case QMetaType::QUrl:
        return QCborValue(variant.toUrl());
    case QMetaType::QUuid:
        return QCborValue(variant.toUuid());
#endif
    case QMetaType::QVariantList:
        return QCborArray::fromVariantList(variant.toList());
    case QMetaType::QVariantMap:
        return QCborMap::fromVariantMap(variant.toMap());
    case QMetaType::QVariantHash:
        return QCborMap::fromVariantHash(variant.toHash());
#ifndef QT_BOOTSTRAPPED
#if QT_CONFIG(regularexpression)
    case QMetaType::QRegularExpression:
        return QCborValue(variant.toRegularExpression());
#endif
    case QMetaType::QJsonValue:
        return fromJsonValue(variant.toJsonValue());
    case QMetaType::QJsonObject:
        return QCborMap::fromJsonObject(variant.toJsonObject());
    case QMetaType::QJsonArray:
        return QCborArray::fromJsonArray(variant.toJsonArray());
    case QMetaType::QJsonDocument: {
        QJsonDocument doc = variant.toJsonDocument();
        if (doc.isArray())
            return QCborArray::fromJsonArray(doc.array());
        return QCborMap::fromJsonObject(doc.object());
    }
    case QMetaType::QCborValue:
        return qvariant_cast<QCborValue>(variant);
    case QMetaType::QCborArray:
        return qvariant_cast<QCborArray>(variant);
    case QMetaType::QCborMap:
        return qvariant_cast<QCborMap>(variant);
    case QMetaType::QCborSimpleType:
        return qvariant_cast<QCborSimpleType>(variant);
#endif
    default:
        break;
    }

    if (variant.isNull())
        return QCborValue(nullptr);

    QString string = variant.toString();
    if (string.isNull())
        return QCborValue();        // undefined
    return string;
}

/*!
    Recursively converts each \l QCborValue in this array using
    QCborValue::toVariant() and returns the QVariantList composed of the
    converted items.

    Conversion to \l QVariant is not completely lossless. Please see the
    documentation in QCborValue::toVariant() for more information.

    \sa fromVariantList(), fromStringList(), toJsonArray(),
        QCborValue::toVariant(), QCborMap::toVariantMap()
 */
QVariantList QCborArray::toVariantList() const
{
    QVariantList retval;
    retval.reserve(size());
    for (qsizetype i = 0; i < size(); ++i)
        retval.append(d->valueAt(i).toVariant());
    return retval;
}

/*!
    Returns a QCborArray containing all the strings found in the \a list list.

    \sa fromVariantList(), fromJsonArray()
 */
QCborArray QCborArray::fromStringList(const QStringList &list)
{
    QCborArray a;
    a.detach(list.size());
    for (const QString &s : list)
        a.d->append(s);
    return a;
}

/*!
    Converts all the items in the \a list to CBOR using
    QCborValue::fromVariant() and returns the array composed of those elements.

    Conversion from \l QVariant is not completely lossless. Please see the
    documentation in QCborValue::fromVariant() for more information.

    \sa toVariantList(), fromStringList(), fromJsonArray(), QCborMap::fromVariantMap()
 */
QCborArray QCborArray::fromVariantList(const QVariantList &list)
{
    QCborArray a;
    a.detach(list.size());
    for (const QVariant &v : list)
        appendVariant(a.d.data(), v);
    return a;
}

/*!
    Converts all JSON items found in the \a array array to CBOR using
    QCborValue::fromJson(), and returns the CBOR array composed of those
    elements.

    This conversion is lossless, as the CBOR type system is a superset of
    JSON's. Moreover, the array returned by this function can be converted back
    to the original \a array by using toJsonArray().

    \sa toJsonArray(), toVariantList(), QCborValue::fromJsonValue(), QCborMap::fromJsonObject()
 */
QCborArray QCborArray::fromJsonArray(const QJsonArray &array)
{
    QCborArray result;
    result.d = array.a;
    return result;
}

/*!
    \overload
    \since 6.3
 */
QCborArray QCborArray::fromJsonArray(QJsonArray &&array) noexcept
{
    QCborArray result;
    result.d = std::exchange(array.a, {});
    return result;

}

/*!
    Converts the CBOR values to QVariant using QCborValue::toVariant() and
    "stringifies" all the CBOR keys in this map, returning the QVariantMap that
    results from that association list.

    QVariantMaps have string keys, unlike CBOR, so the conversion of a QCborMap
    to QVariantMap will imply a step of "stringification" of the key values.
    See QCborMap::toJsonObject() for details.

    In addition, the conversion to \l QVariant is not completely lossless.
    Please see the documentation in QCborValue::toVariant() for more
    information.

    \sa fromVariantMap(), toVariantHash(), toJsonObject(), QCborValue::toVariant(),
        QCborArray::toVariantList()
 */
QVariantMap QCborMap::toVariantMap() const
{
    QVariantMap retval;
    for (qsizetype i = 0; i < 2 * size(); i += 2)
        retval.insert(makeString(d.data(), i), d->valueAt(i + 1).toVariant());
    return retval;
}

/*!
    Converts the CBOR values to QVariant using QCborValue::toVariant() and
    "stringifies" all the CBOR keys in this map, returning the QVariantHash that
    results from that association list.

    QVariantMaps have string keys, unlike CBOR, so the conversion of a QCborMap
    to QVariantMap will imply a step of "stringification" of the key values.
    See QCborMap::toJsonObject() for details.

    In addition, the conversion to \l QVariant is not completely lossless.
    Please see the documentation in QCborValue::toVariant() for more
    information.

    \sa fromVariantHash(), toVariantMap(), toJsonObject(), QCborValue::toVariant(),
        QCborArray::toVariantList()
 */
QVariantHash QCborMap::toVariantHash() const
{
    QVariantHash retval;
    retval.reserve(size());
    for (qsizetype i = 0; i < 2 * size(); i += 2)
        retval.insert(makeString(d.data(), i), d->valueAt(i + 1).toVariant());
    return retval;
}

/*!
    Converts all the items in \a map to CBOR using QCborValue::fromVariant()
    and returns the map composed of those elements.

    Conversion from \l QVariant is not completely lossless. Please see the
    documentation in QCborValue::fromVariant() for more information.

    \sa toVariantMap(), fromVariantHash(), fromJsonObject(), QCborValue::fromVariant()
 */
QCborMap QCborMap::fromVariantMap(const QVariantMap &map)
{
    QCborMap m;
    m.detach(map.size());
    QCborContainerPrivate *d = m.d.data();

    auto it = map.begin();
    auto end = map.end();
    for ( ; it != end; ++it) {
        d->append(it.key());
        appendVariant(d, it.value());
    }
    return m;
}

/*!
    Converts all the items in \a hash to CBOR using QCborValue::fromVariant()
    and returns the map composed of those elements.

    Conversion from \l QVariant is not completely lossless. Please see the
    documentation in QCborValue::fromVariant() for more information.

    \sa toVariantHash(), fromVariantMap(), fromJsonObject(), QCborValue::fromVariant()
 */
QCborMap QCborMap::fromVariantHash(const QVariantHash &hash)
{
    QCborMap m;
    m.detach(hash.size());
    QCborContainerPrivate *d = m.d.data();

    auto it = hash.begin();
    auto end = hash.end();
    for ( ; it != end; ++it) {
        d->append(it.key());
        appendVariant(d, it.value());
    }
    return m;
}

/*!
    Converts all JSON items found in the \a obj object to CBOR using
    QCborValue::fromJson(), and returns the map composed of those elements.

    This conversion is lossless, as the CBOR type system is a superset of
    JSON's. Moreover, the map returned by this function can be converted back
    to the original \a obj by using toJsonObject().

    \sa toJsonObject(), toVariantMap(), QCborValue::fromJsonValue(), QCborArray::fromJsonArray()
 */
QCborMap QCborMap::fromJsonObject(const QJsonObject &obj)
{
    QCborMap result;
    result.d = obj.o;
    return result;
}

/*!
    \overload
    \since 6.3
 */
QCborMap QCborMap::fromJsonObject(QJsonObject &&obj) noexcept
{
    QCborMap result;
    result.d = std::exchange(obj.o, {});
    return result;
}

QT_END_NAMESPACE
