// Copyright (C) 2016 The Qt Company Ltd.

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include "qtextimagehandler_p.h"

#include <qbuffer.h>

#include <qguiapplication.h>

#include <qtextformat.h>

#include <qpainter.h>

#include <qdebug.h>

#include <qicon.h>

#include <qimagereader.h>

#include <qpixmapcache.h>

#include <qthread.h>

#include <qpa/qplatformintegration.h>

#include <private/qguiapplication_p.h>

#include <private/qhexstring_p.h>

#include <private/qtextengine_p.h>

#include <limits>

QT_BEGIN_NAMESPACE

using namespace Qt::StringLiterals;

static inline QUrl findAtNxFileOrResource(const QString &baseFileName,

                                          qreal targetDevicePixelRatio,

                                          qreal *sourceDevicePixelRatio,

                                          QString *name)

{

    // qt_findAtNxFile expects a file name that can be tested with QFile::exists.

    // so if the format.name() is a file:/ or qrc:/ URL, then we need to strip away the schema.

    QString localFile;

    const QUrl url(baseFileName);

    bool hasFileScheme = false;

    bool isResource = false;

    if (url.isLocalFile()) {

        localFile = url.toLocalFile();

        hasFileScheme = true;

    } else if (baseFileName.startsWith("qrc:/"_L1)) {

        // QFile::exists() can only handle ":/file.txt"

        localFile = baseFileName.sliced(3);

        isResource = true;

    } else {

        localFile = baseFileName;

        isResource = baseFileName.startsWith(":/"_L1);

    }

    *name = qt_findAtNxFile(localFile, targetDevicePixelRatio, sourceDevicePixelRatio);

    if (hasFileScheme)

        return QUrl::fromLocalFile(*name);

    if (isResource)

        return QUrl("qrc"_L1 + *name);

    return QUrl(*name);

}

static QImage getImage(QTextDocument *doc, const QTextImageFormat &format,

                       const qreal devicePixelRatio = 1.0, const QSizeF &size = {})

{

    qreal sourcePixelRatio = 1.0;

    QString name;

    const QUrl url = findAtNxFileOrResource(format.name(), devicePixelRatio, &sourcePixelRatio, &name);

    const QVariant data = doc->resource(QTextDocument::ImageResource, url);

    // directly provided as QPixmap/QImage or already cached

    if (data.userType() == QMetaType::QPixmap || data.userType() == QMetaType::QImage)

        return data.value<QImage>();

    // some image formats are scalable (e.g. svg) so we should not store a single

    // QImage as QTextDocument::ImageResource to avoid scaling artefacts later on.

    // But otoh we don't want to load them on every usage. Therefore cache the result

    // in QPixmapCache

    const bool canUsePixmapCache = (QThread::isMainThread()

                                    || QGuiApplicationPrivate::platformIntegration()->hasCapability(

                                            QPlatformIntegration::ThreadedPixmaps));

    const auto buildCacheKey = [](const QString &name, const QSizeF &size, qreal dpr) -> QString {

        return QLatin1String("qt_textimagehandler_") % name

                % HexString<int>(size.width())

                % HexString<int>(size.height())

                % HexString<qint16>(qRound(dpr * 1000));

    };

    const QString cacheKey = canUsePixmapCache

            ? buildCacheKey(name, size * devicePixelRatio, sourcePixelRatio)

            : QString();

    if (canUsePixmapCache) {

        QPixmap pm;

        if (QPixmapCache::find(cacheKey, &pm))

            return pm.toImage();

    }

    const auto readImage = [&](auto &&content) {

        QImageReader imgReader(content);

        if (imgReader.canRead()) {

            const bool supportsScaledSize = imgReader.supportsOption(QImageIOHandler::ScaledSize);

            if (size.isValid() && supportsScaledSize)

                imgReader.setScaledSize((size * devicePixelRatio).toSize());

            QImage result = imgReader.read();

            result.setDevicePixelRatio(sourcePixelRatio);

            if (!supportsScaledSize)

                doc->addResource(QTextDocument::ImageResource, url, result);

            else if (canUsePixmapCache)

                QPixmapCache::insert(cacheKey, QPixmap::fromImage(result));

            return result;

        }

        return QImage();

    };

Unexecuted instantiation: qtextimagehandler.cpp:auto getImage(QTextDocument*, QTextImageFormat const&, double, QSizeF const&)::$_0::operator()<QBuffer*>(QBuffer*&&) const

Unexecuted instantiation: qtextimagehandler.cpp:auto getImage(QTextDocument*, QTextImageFormat const&, double, QSizeF const&)::$_0::operator()<QString&>(QString&) const

    QImage result;

    if (data.metaType() == QMetaType::fromType<QByteArray>()) {

        QByteArray ba(data.toByteArray());

        QBuffer buf(&ba);

        result = readImage(&buf);

    }

    if (result.isNull())

        result = readImage(name);

    if (result.isNull())

        result = QImage(":/qt-project.org/styles/commonstyle/images/file-16.png"_L1);

    return result;

}

static QSize getSize(QTextDocument *doc, const QTextImageFormat &format)

{

    const bool hasWidth = format.hasProperty(QTextFormat::ImageWidth);

    int width = qRound(format.width());

    const bool hasHeight = format.hasProperty(QTextFormat::ImageHeight);

    const int height = qRound(format.height());

    const bool hasMaxWidth = format.hasProperty(QTextFormat::ImageMaxWidth);

    const auto maxWidth = format.maximumWidth();

    int effectiveMaxWidth = std::numeric_limits<int>::max();

    if (hasMaxWidth) {

        if (maxWidth.type() == QTextLength::PercentageLength)

            effectiveMaxWidth = (doc->pageSize().width() - 2 * doc->documentMargin()) * maxWidth.value(100) / 100;

        else

            effectiveMaxWidth = maxWidth.rawValue();

        width = qMin(effectiveMaxWidth, width);

    }

    QImage source;

    QSize size(width, height);

    if (!hasWidth || !hasHeight) {

        source = getImage(doc, format);

        QSizeF sourceSize = source.deviceIndependentSize();

        if (sourceSize.width() > effectiveMaxWidth) {

            // image is bigger than effectiveMaxWidth, scale it down

            sourceSize.setHeight(effectiveMaxWidth * (sourceSize.height() / qreal(sourceSize.width())));

            sourceSize.setWidth(effectiveMaxWidth);

        }

        if (!hasWidth) {

            if (!hasHeight)

                size.setWidth(sourceSize.width());

            else

                size.setWidth(qMin(effectiveMaxWidth, qRound(height * (sourceSize.width() / qreal(sourceSize.height())))));

        }

        if (!hasHeight) {

            if (!hasWidth)

                size.setHeight(sourceSize.height());

            else

                size.setHeight(qRound(width * (sourceSize.height() / qreal(sourceSize.width()))));

        }

    }

    const QPaintDevice *pdev = doc->documentLayout()->paintDevice();

    if (pdev)

        size *= qreal(pdev->logicalDpiY()) / qreal(qt_defaultDpi());

    return size;

}

QTextImageHandler::QTextImageHandler(QObject *parent)

    : QObject(parent)

{

}

QSizeF QTextImageHandler::intrinsicSize(QTextDocument *doc, int posInDocument, const QTextFormat &format)

{

    Q_UNUSED(posInDocument);

    const QTextImageFormat imageFormat = format.toImageFormat();

    return getSize(doc, imageFormat);

}

QImage QTextImageHandler::image(QTextDocument *doc, const QTextImageFormat &imageFormat)

{

    Q_ASSERT(doc != nullptr);

    return getImage(doc, imageFormat);

}

void QTextImageHandler::drawObject(QPainter *p, const QRectF &rect, QTextDocument *doc, int posInDocument, const QTextFormat &format)

{

    Q_UNUSED(posInDocument);

        const QTextImageFormat imageFormat = format.toImageFormat();

    const QImage image = getImage(doc, imageFormat, p->device()->devicePixelRatio(), rect.size());

    p->drawImage(rect, image, image.rect());

}

QT_END_NAMESPACE

#include "moc_qtextimagehandler_p.cpp"