//    Copyright (C) 2024 Jakub Melka
//
//    This file is part of PDF4QT.
//
//    PDF4QT is free software: you can redistribute it and/or modify
//    it under the terms of the GNU Lesser General Public License as published by
//    the Free Software Foundation, either version 3 of the License, or
//    with the written consent of the copyright owner, any later version.
//
//    PDF4QT is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU Lesser General Public License for more details.
//
//    You should have received a copy of the GNU Lesser General Public License
//    along with PDF4QT.  If not, see <https://www.gnu.org/licenses/>.

#include "pdfblpainter.h"
#include "pdffont.h"

#include <QThread>
#include <QRawFont>
#include <QPainterPath>
#include <QPaintEngine>
#include <QPainterPathStroker>

#ifdef Q_OS_WIN
#include <Blend2d.h>
#else
#include <blend2d.h>
#endif

namespace pdf
{

class PDFBLPaintEngine : public QPaintEngine
{
public:
    explicit PDFBLPaintEngine(QImage& qtOffscreenBuffer, bool isMultithreaded);

    virtual bool begin(QPaintDevice*) override;
    virtual bool end() override;
    virtual void updateState(const QPaintEngineState& updatedState) override;
    virtual void drawRects(const QRect* rects, int rectCount) override;
    virtual void drawRects(const QRectF* rects, int rectCount) override;
    virtual void drawLines(const QLine* lines, int lineCount) override;
    virtual void drawLines(const QLineF* lines, int lineCount) override;
    virtual void drawEllipse(const QRectF& r) override;
    virtual void drawEllipse(const QRect& r) override;
    virtual void drawPath(const QPainterPath& path) override;
    virtual void drawPoints(const QPointF* points, int pointCount) override;
    virtual void drawPoints(const QPoint* points, int pointCount) override;
    virtual void drawPolygon(const QPointF* points, int pointCount, PolygonDrawMode mode) override;
    virtual void drawPolygon(const QPoint* points, int pointCount, PolygonDrawMode mode) override;
    virtual void drawPixmap(const QRectF& r, const QPixmap& pm, const QRectF& sr) override;
    virtual void drawTextItem(const QPointF& p, const QTextItem& textItem) override;
    virtual void drawTiledPixmap(const QRectF& r, const QPixmap& pixmap, const QPointF& s) override;
    virtual void drawImage(const QRectF& r, const QImage& pm, const QRectF& sr, Qt::ImageConversionFlags flags) override;
    virtual Type type() const override;

    static PaintEngineFeatures getStaticFeatures();

private:

    /// Get BL matrix from transformation
    static BLMatrix2D getBLMatrix(QTransform transform);

    static BLPoint getBLPoint(const QPoint& point);
    static BLPoint getBLPoint(const QPointF& point);

    /// Get BL rect from regular rect
    static BLRectI getBLRect(QRect rect);

    /// Get BL rect from regular rect
    static BLRect getBLRect(QRectF rect);

    /// Get BL path from path
    static BLPath getBLPath(const QPainterPath& path);

    /// Set pen to the context
    static void setBLPen(BLContext& context, const QPen& pen);

    /// Set brush to the context
    static void setBLBrush(BLContext& context, const QBrush& brush);

    /// Load font
    static bool loadBLFont(BLFont& font, QString fontName, PDFReal fontSize);

    /// Returns composition operator
    static BLCompOp getBLCompOp(QPainter::CompositionMode mode);

    void drawPathImpl(const QPainterPath& path, bool enableStroke, bool enableFill, bool forceFill = false);

    void setFillRule(Qt::FillRule fillRule);
    void updateFont(QFont newFont);
    void setPathFillMode(PolygonDrawMode mode, QPainterPath& path);
    void updateClipping(std::optional<QRegion> clipRegion,
                        std::optional<QPainterPath> clipPath,
                        Qt::ClipOperation clipOperation);

    bool isStrokeActive() const { return m_currentPen.style() != Qt::NoPen; }
    bool isFillActive() const { return m_currentBrush.style() != Qt::NoBrush; }

    enum class ClipMode
    {
        NoClip,
        NotVisible,
        NeedsResolve
    };

    ClipMode resolveClipping(const QLineF& line) const;
    ClipMode resolveClipping(const QPointF& point) const;
    ClipMode resolveClipping(const QRectF& rect) const;
    ClipMode resolveClipping(const QPainterPath& path) const;

    QImage& m_qtOffscreenBuffer;
    std::optional<BLContext> m_blContext;
    std::optional<BLImage> m_blOffscreenBuffer;
    bool m_isMultithreaded;

    QPen m_currentPen;
    QBrush m_currentBrush;
    QFont m_currentFont;
    QRawFont m_currentRawFont;
    QTransform m_currentTransform;

    bool m_currentIsClipEnabled = false;
    bool m_clipSingleRect = false;
    std::optional<QPainterPath> m_finalClipPath;
    QRectF m_finalClipPathBoundingBox;
};

PDFBLPaintDevice::PDFBLPaintDevice(QImage& offscreenBuffer, bool isMultithreaded) :
    m_offscreenBuffer(offscreenBuffer),
    m_paintEngine(new PDFBLPaintEngine(offscreenBuffer, isMultithreaded))
{

}

PDFBLPaintDevice::~PDFBLPaintDevice()
{
    delete m_paintEngine;
    m_paintEngine = nullptr;
}

int PDFBLPaintDevice::devType() const
{
    return QInternal::CustomRaster;
}

QPaintEngine* PDFBLPaintDevice::paintEngine() const
{
    return m_paintEngine;
}

int PDFBLPaintDevice::metric(PaintDeviceMetric metric) const
{
    switch (metric)
    {
    case QPaintDevice::PdmWidth:
        return m_offscreenBuffer.width();
    case QPaintDevice::PdmHeight:
        return m_offscreenBuffer.height();
    case QPaintDevice::PdmWidthMM:
        return m_offscreenBuffer.widthMM();
    case QPaintDevice::PdmHeightMM:
        return m_offscreenBuffer.heightMM();
    case QPaintDevice::PdmNumColors:
        return m_offscreenBuffer.colorCount();
    case QPaintDevice::PdmDepth:
        return m_offscreenBuffer.depth();
    case QPaintDevice::PdmDpiX:
        return m_offscreenBuffer.logicalDpiX();
    case QPaintDevice::PdmDpiY:
        return m_offscreenBuffer.logicalDpiY();
    case QPaintDevice::PdmPhysicalDpiX:
        return m_offscreenBuffer.physicalDpiX();
    case QPaintDevice::PdmPhysicalDpiY:
        return m_offscreenBuffer.physicalDpiY();
    case QPaintDevice::PdmDevicePixelRatio:
        return m_offscreenBuffer.devicePixelRatio();
    case QPaintDevice::PdmDevicePixelRatioScaled:
        return m_offscreenBuffer.devicePixelRatioFScale();
    default:
        Q_ASSERT(false);
        break;
    }

    return 0;
}

PDFBLPaintEngine::PDFBLPaintEngine(QImage& qtOffscreenBuffer, bool isMultithreaded) :
    QPaintEngine(getStaticFeatures()),
    m_qtOffscreenBuffer(qtOffscreenBuffer),
    m_isMultithreaded(isMultithreaded)
{

}

bool PDFBLPaintEngine::begin(QPaintDevice*)
{
    if (isActive())
    {
        return false;
    }

    m_blContext.emplace();
    m_blOffscreenBuffer.emplace();

    BLContextCreateInfo info{};

    if (m_isMultithreaded)
    {
        info.flags = BL_CONTEXT_CREATE_FLAG_FALLBACK_TO_SYNC;
        info.threadCount = QThread::idealThreadCount();
    }

    m_blContext->setHint(BL_CONTEXT_HINT_RENDERING_QUALITY, BL_RENDERING_QUALITY_MAX_VALUE);

    m_blOffscreenBuffer->createFromData(m_qtOffscreenBuffer.width(), m_qtOffscreenBuffer.height(), BL_FORMAT_PRGB32, m_qtOffscreenBuffer.bits(), m_qtOffscreenBuffer.bytesPerLine());
    if (m_blContext->begin(m_blOffscreenBuffer.value(), info) == BL_SUCCESS)
    {
        m_blContext->clearAll();

        qreal devicePixelRatio = m_qtOffscreenBuffer.devicePixelRatioF();
        m_blContext->scale(devicePixelRatio);
        m_blContext->userToMeta();

        setBLPen(m_blContext.value(), m_currentPen);
        setBLBrush(m_blContext.value(), m_currentBrush);
        updateFont(QFont());
        return true;
    }
    else
    {
        m_blContext.reset();
        m_blOffscreenBuffer.reset();
    }

    return false;
}

bool PDFBLPaintEngine::end()
{
    if (!isActive())
    {
        return false;
    }

    m_blContext->end();
    m_blContext.reset();
    m_blOffscreenBuffer.reset();
    return true;
}

void PDFBLPaintEngine::updateFont(QFont newFont)
{
    m_currentFont = newFont;
    m_currentFont.setHintingPreference(QFont::PreferNoHinting);

    PDFReal pixelSize = m_currentFont.pixelSize();
    if (pixelSize == -1)
    {
        PDFReal pointSizeF = m_currentFont.pointSizeF();
        PDFReal dpi = m_qtOffscreenBuffer.logicalDpiY();
        pixelSize = pointSizeF / 72 * dpi;
        m_currentFont.setPixelSize(pixelSize);
    }

    m_currentRawFont = QRawFont::fromFont(m_currentFont);
}

void PDFBLPaintEngine::updateState(const QPaintEngineState& updatedState)
{
    if (updatedState.state().testFlag(QPaintEngine::DirtyPen))
    {
        m_currentPen = updatedState.pen();
        setBLPen(m_blContext.value(), updatedState.pen());
    }

    if (updatedState.state().testFlag(QPaintEngine::DirtyBrush))
    {
        m_currentBrush = updatedState.brush();
        setBLBrush(m_blContext.value(), updatedState.brush());
    }

    if (updatedState.state().testFlag(QPaintEngine::DirtyCompositionMode))
    {
        m_blContext->setCompOp(getBLCompOp(updatedState.compositionMode()));
    }

    if (updatedState.state().testFlag(QPaintEngine::DirtyOpacity))
    {
        m_blContext->setGlobalAlpha(updatedState.opacity());
    }

    if (updatedState.state().testFlag(QPaintEngine::DirtyTransform))
    {
        m_currentTransform = updatedState.transform();
        m_blContext->setMatrix(getBLMatrix(updatedState.transform()));
    }

    if (updatedState.state().testFlag(QPaintEngine::DirtyFont))
    {
        updateFont(updatedState.font());
    }

    if (updatedState.state().testFlag(QPaintEngine::DirtyClipEnabled))
    {
        m_currentIsClipEnabled = updatedState.isClipEnabled();
    }

    if (updatedState.state().testFlag(QPaintEngine::DirtyHints))
    {
        // Do nothing
    }

    if (updatedState.state().testAnyFlags(QPaintEngine::DirtyClipPath | QPaintEngine::DirtyClipRegion))
    {
        std::optional<QRegion> clipRegion;
        std::optional<QPainterPath> clipPath;

        if (updatedState.state().testFlag(QPaintEngine::DirtyClipRegion))
        {
            clipRegion = updatedState.clipRegion();
        }

        if (updatedState.state().testFlag(QPaintEngine::DirtyClipPath))
        {
            clipPath = updatedState.clipPath();
        }

        updateClipping(std::move(clipRegion), std::move(clipPath), updatedState.clipOperation());
    }
}

void PDFBLPaintEngine::drawRects(const QRect* rects, int rectCount)
{
    QRect boundingRect;

    BLArray<BLRectI> blRects;
    blRects.reserve(rectCount);

    for (int i = 0; i < rectCount; ++i)
    {
        boundingRect = boundingRect.united(rects[i]);
        blRects.append(getBLRect(rects[i]));
    }

    QRect mappedBoundingRect = m_currentTransform.mapRect(boundingRect);
    ClipMode clipMode = resolveClipping(mappedBoundingRect);
    switch (clipMode)
    {
        case ClipMode::NoClip:
            break;

        case ClipMode::NotVisible:
            return;

        case ClipMode::NeedsResolve:
        {
            for (int i = 0; i < rectCount; ++i)
            {
                QPainterPath path;
                path.addRect(rects[i]);
                drawPathImpl(path, true, true);
            }
            return;
        }
    }

    if (isFillActive())
    {
        m_blContext->fillRectArray(blRects.view());
    }

    if (isStrokeActive())
    {
        m_blContext->strokeRectArray(blRects.view());
    }
}

void PDFBLPaintEngine::drawRects(const QRectF* rects, int rectCount)
{
    QRectF boundingRect;

    BLArray<BLRect> blRects;
    blRects.reserve(rectCount);

    for (int i = 0; i < rectCount; ++i)
    {
        boundingRect = boundingRect.united(rects[i]);
        blRects.append(getBLRect(rects[i]));
    }

    QRectF mappedBoundingRect = m_currentTransform.mapRect(boundingRect);
    ClipMode clipMode = resolveClipping(mappedBoundingRect);
    switch (clipMode)
    {
        case ClipMode::NoClip:
            break;

        case ClipMode::NotVisible:
            return;

        case ClipMode::NeedsResolve:
        {
            for (int i = 0; i < rectCount; ++i)
            {
                QPainterPath path;
                path.addRect(rects[i]);
                drawPathImpl(path, true, true);
            }
            return;
        }
    }

    if (isFillActive())
    {
        m_blContext->fillRectArray(blRects.view());
    }

    if (isStrokeActive())
    {
        m_blContext->strokeRectArray(blRects.view());
    }
}

void PDFBLPaintEngine::drawLines(const QLine* lines, int lineCount)
{
    if (!isStrokeActive())
    {
        return;
    }

    for (int i = 0; i < lineCount; ++i)
    {
        const QLine& line = lines[i];
        ClipMode clipMode = resolveClipping(m_currentTransform.map(line));

        switch (clipMode)
        {
            case ClipMode::NoClip:
                // Do as normal
                break;

            case ClipMode::NotVisible:
                // Graphics is not visible
                return;

            case ClipMode::NeedsResolve:
            {
                QLineF lineF = line.toLineF();
                if (m_finalClipPath->isEmpty() || qFuzzyIsNull(lineF.length()))
                {
                    return;
                }

                QLineF normalVectorLine = lineF.normalVector().unitVector();
                QPointF normalVector = normalVectorLine.p2() - normalVectorLine.p1();
                qreal widthF = m_currentPen.widthF() * 0.5;

                QPainterPath path;
                path.moveTo(lineF.p1() + normalVector * widthF);
                path.lineTo(lineF.p2() + normalVector * widthF);
                path.lineTo(lineF.p2() - normalVector * widthF);
                path.lineTo(lineF.p1() - normalVector * widthF);
                path.closeSubpath();

                drawPathImpl(path, true, false);
                return;
            }
        }

        m_blContext->strokeLine(line.x1(), line.y1(), line.x2(), line.y2());
    }
}

void PDFBLPaintEngine::drawLines(const QLineF* lines, int lineCount)
{
    if (!isStrokeActive())
    {
        return;
    }

    for (int i = 0; i < lineCount; ++i)
    {
        const QLineF& line = lines[i];

        ClipMode clipMode = resolveClipping(m_currentTransform.map(line));
        switch (clipMode)
        {
            case ClipMode::NoClip:
                // Do as normal
                break;

            case ClipMode::NotVisible:
                // Graphics is not visible
                return;

            case ClipMode::NeedsResolve:
            {
                if (m_finalClipPath->isEmpty() || qFuzzyIsNull(line.length()))
                {
                    return;
                }

                QLineF normalVectorLine = line.normalVector().unitVector();
                QPointF normalVector = normalVectorLine.p2() - normalVectorLine.p1();
                qreal widthF = m_currentPen.widthF() * 0.5;

                QPainterPath path;
                path.moveTo(line.p1() + normalVector * widthF);
                path.lineTo(line.p2() + normalVector * widthF);
                path.lineTo(line.p2() - normalVector * widthF);
                path.lineTo(line.p1() - normalVector * widthF);
                path.closeSubpath();

                drawPathImpl(path, true, false);
                return;
            }
        }

        m_blContext->strokeLine(line.x1(), line.y1(), line.x2(), line.y2());
    }
}

void PDFBLPaintEngine::drawEllipse(const QRectF& r)
{
    QPainterPath path;
    path.addEllipse(r);
    drawPathImpl(path, true, true);
}

void PDFBLPaintEngine::drawEllipse(const QRect& r)
{
    QPainterPath path;
    path.addEllipse(r);
    drawPathImpl(path, true, true);
}

void PDFBLPaintEngine::drawPath(const QPainterPath& path)
{
    drawPathImpl(path, true, true);
}

void PDFBLPaintEngine::drawPathImpl(const QPainterPath& path, bool enableStroke, bool enableFill, bool forceFill)
{
    QPainterPath transformedPath = m_currentTransform.map(path);
    ClipMode clipMode = resolveClipping(transformedPath);

    setFillRule(path.fillRule());

    switch (clipMode)
    {
        case ClipMode::NoClip:
            // Do as normal
            break;

        case ClipMode::NotVisible:
            // Graphics is not visible
            return;

        case ClipMode::NeedsResolve:
        {
            if (m_finalClipPath->isEmpty())
            {
                return;
            }

            if ((isFillActive() && enableFill) || forceFill)
            {
                QPainterPath fillPath = transformedPath.intersected(m_finalClipPath.value());

                if (!fillPath.isEmpty())
                {
                    m_blContext->save();
                    m_blContext->resetMatrix();
                    m_blContext->fillPath(getBLPath(fillPath));
                    m_blContext->restore();
                }
            }

            if (isStrokeActive() && enableStroke)
            {
                QPainterPathStroker stroker(m_currentPen);
                QPainterPath strokedPath = stroker.createStroke(path);
                QPainterPath transformedStrokedPath = m_currentTransform.map(strokedPath);
                QPainterPath finalTransformedStrokedPath = transformedStrokedPath.intersected(m_finalClipPath.value());

                BLVarCore strokeStyle;
                if (!finalTransformedStrokedPath.isEmpty() && m_blContext->getStrokeStyle(strokeStyle) == BL_SUCCESS)
                {
                    m_blContext->save();
                    m_blContext->resetMatrix();
                    m_blContext->setFillStyle(strokeStyle);
                    m_blContext->fillPath(getBLPath(finalTransformedStrokedPath));
                    m_blContext->restore();
                }
            }

            return;
        }
    }

    BLPath blPath = getBLPath(path);

    if ((isFillActive() && enableFill) || forceFill)
    {
        m_blContext->fillPath(blPath);
    }

    if (isStrokeActive() && enableStroke)
    {
        m_blContext->strokePath(blPath);
    }
}

void PDFBLPaintEngine::drawPoints(const QPointF* points, int pointCount)
{
    m_blContext->save();
    m_blContext->setFillStyle(BLRgba32(m_currentPen.color().rgba()));

    for (int i = 0; i < pointCount; ++i)
    {
        const QPointF& c = points[i];

        if (resolveClipping(m_currentTransform.map(c)) == ClipMode::NotVisible)
        {
            continue;
        }

        BLEllipse blEllipse(c.x(), c.y(), m_currentPen.widthF() * 0.5, m_currentPen.widthF() * 0.5);
        m_blContext->fillEllipse(blEllipse);
    }

    m_blContext->restore();
}

void PDFBLPaintEngine::drawPoints(const QPoint* points, int pointCount)
{
    m_blContext->save();
    m_blContext->setFillStyle(BLRgba32(m_currentPen.color().rgba()));

    for (int i = 0; i < pointCount; ++i)
    {
        const QPointF& c = points[i];

        if (resolveClipping(m_currentTransform.map(c)) == ClipMode::NotVisible)
        {
            continue;
        }

        BLEllipse blEllipse(c.x(), c.y(), m_currentPen.widthF() * 0.5, m_currentPen.widthF() * 0.5);
        m_blContext->fillEllipse(blEllipse);
    }

    m_blContext->restore();
}

void PDFBLPaintEngine::drawPolygon(const QPointF* points, int pointCount, PolygonDrawMode mode)
{
    QPainterPath path;
    QPolygonF polygon;
    polygon.assign(points, points + pointCount);
    path.addPolygon(polygon);

    setPathFillMode(mode, path);

    drawPathImpl(path, true, mode != QPaintEngine::PolylineMode);
}

void PDFBLPaintEngine::drawPolygon(const QPoint* points, int pointCount, PolygonDrawMode mode)
{
    QPainterPath path;
    QPolygonF polygon;
    polygon.assign(points, points + pointCount);
    path.addPolygon(polygon);

    setPathFillMode(mode, path);

    drawPathImpl(path, true, mode != QPaintEngine::PolylineMode);
}

void PDFBLPaintEngine::drawPixmap(const QRectF& r, const QPixmap& pm, const QRectF& sr)
{
    drawImage(r, pm.toImage(), sr, Qt::ImageConversionFlags());
}

void PDFBLPaintEngine::drawTextItem(const QPointF& p, const QTextItem& textItem)
{
    if (m_currentRawFont.isValid())
    {
        QString text = textItem.text();
        QList<quint32> glyphIndices = m_currentRawFont.glyphIndexesForString(text);
        QList<QPointF> glyphPositions = m_currentRawFont.advancesForGlyphIndexes(glyphIndices);

        QPointF currentPosition = p;
        QPainterPath path;
        for (int i = 0; i < glyphIndices.size(); ++i)
        {
            QPainterPath glyphPath = m_currentRawFont.pathForGlyph(glyphIndices[i]);
            glyphPath.translate(currentPosition);
            path.addPath(glyphPath);
            currentPosition += glyphPositions[i];
        }

        m_blContext->save();
        setFillRule(path.fillRule());
        m_blContext->setFillStyle(BLRgba32(m_currentPen.color().rgba()));
        drawPathImpl(path, false, true, true);
        m_blContext->restore();
    }
}

void PDFBLPaintEngine::drawTiledPixmap(const QRectF& r, const QPixmap& pixmap, const QPointF& s)
{
    QImage image = pixmap.toImage();

    if (image.format() != QImage::Format_ARGB32_Premultiplied)
    {
        image.convertTo(QImage::Format_ARGB32_Premultiplied);
    }

    int tilesX = qCeil(r.width() / pixmap.width());
    int tilesY = qCeil(r.height() / pixmap.height());

    BLImage blImage;
    blImage.createFromData(image.width(), image.height(), BL_FORMAT_PRGB32, image.bits(), image.bytesPerLine());

    BLImage blDrawImage;
    blDrawImage.assignDeep(blImage);

    for (int x = 0; x < tilesX; ++x)
    {
        for (int y = 0; y < tilesY; ++y)
        {
            QPointF tilePos = QPointF(r.left() + x * pixmap.width() + s.x(),
                                      r.top() + y * pixmap.height() + s.y());

            if (tilePos.x() < r.right() && tilePos.y() < r.bottom())
            {
                m_blContext->blitImage(getBLPoint(tilePos), blDrawImage);
            }
        }
    }
}

void PDFBLPaintEngine::drawImage(const QRectF& r, const QImage& pm, const QRectF& sr, Qt::ImageConversionFlags flags)
{
    Q_UNUSED(flags);

    QRectF transformedRect = m_currentTransform.mapRect(r);
    ClipMode clipMode = resolveClipping(transformedRect);

    if (clipMode == ClipMode::NotVisible)
    {
        return;
    }

    QImage image = pm;

    if (image.format() != QImage::Format_ARGB32_Premultiplied)
    {
        image.convertTo(QImage::Format_ARGB32_Premultiplied);
    }

    if (clipMode == ClipMode::NeedsResolve)
    {
        QImage mask(image.size(), QImage::Format_ARGB32);
        mask.fill(Qt::transparent);

        QPainter maskPainter(&mask);
        maskPainter.setCompositionMode(QPainter::CompositionMode_Source);

        QPainterPath path = m_finalClipPath.value();
        path = m_currentTransform.inverted().map(path);

        maskPainter.fillPath(path, Qt::white);
        maskPainter.end();

        QPainter imagePainter(&image);
        imagePainter.setCompositionMode(QPainter::CompositionMode_DestinationIn);
        imagePainter.drawImage(0, 0, mask);
        imagePainter.end();
    }

    BLImage blImage;
    blImage.createFromData(image.width(), image.height(), BL_FORMAT_PRGB32, image.bits(), image.bytesPerLine());

    BLImage blDrawImage;
    blDrawImage.assignDeep(blImage);

    m_blContext->blitImage(BLRect(r.x(), r.y(), r.width(), r.height()),
                           blDrawImage,
                           BLRectI(sr.x(), sr.y(), sr.width(), sr.height()));
}

QPaintEngine::Type PDFBLPaintEngine::type() const
{
    return User;
}

QPaintEngine::PaintEngineFeatures PDFBLPaintEngine::getStaticFeatures()
{
    return PrimitiveTransform | PixmapTransform | LinearGradientFill |
           RadialGradientFill | ConicalGradientFill | AlphaBlend |
           PorterDuff | PainterPaths | Antialiasing | ConstantOpacity |
           BlendModes | PaintOutsidePaintEvent;
}


BLMatrix2D PDFBLPaintEngine::getBLMatrix(QTransform transform)
{
    BLMatrix2D matrix;
    matrix.reset(transform.m11(), transform.m12(), transform.m21(), transform.m22(), transform.dx(), transform.dy());
    return matrix;
}

BLPoint PDFBLPaintEngine::getBLPoint(const QPoint& point)
{
    return BLPoint(point.x(), point.y());
}

BLPoint PDFBLPaintEngine::getBLPoint(const QPointF& point)
{
    return BLPoint(point.x(), point.y());
}

BLRectI PDFBLPaintEngine::getBLRect(QRect rect)
{
    return BLRectI(rect.x(), rect.y(), rect.width(), rect.height());
}

BLRect PDFBLPaintEngine::getBLRect(QRectF rect)
{
    return BLRect(rect.x(), rect.y(), rect.width(), rect.height());
}

BLPath PDFBLPaintEngine::getBLPath(const QPainterPath& path)
{
    BLPath blPath;

    int elementCount = path.elementCount();
    for (int i = 0; i < elementCount; ++i) {
        const QPainterPath::Element& element = path.elementAt(i);

        switch (element.type)
        {
        case QPainterPath::MoveToElement:
            blPath.moveTo(element.x, element.y);
            break;

        case QPainterPath::LineToElement:
            blPath.lineTo(element.x, element.y);
            break;

        case QPainterPath::CurveToElement:
            if (i + 2 < elementCount)
            {
                const QPainterPath::Element& ctrlPoint1 = path.elementAt(i++);
                const QPainterPath::Element& ctrlPoint2 = path.elementAt(i++);
                const QPainterPath::Element& endPoint = path.elementAt(i);
                blPath.cubicTo(ctrlPoint1.x, ctrlPoint1.y, ctrlPoint2.x, ctrlPoint2.y, endPoint.x, endPoint.y);
            }
            break;

        case QPainterPath::CurveToDataElement:
            Q_ASSERT(false);
            break;
        }
    }

    return blPath;
}

void PDFBLPaintEngine::setBLPen(BLContext& context, const QPen& pen)
{
    const Qt::PenCapStyle capStyle = pen.capStyle();
    const Qt::PenJoinStyle joinStyle = pen.joinStyle();
    const QColor color = pen.color();
    const qreal width = pen.widthF();
    const qreal miterLimit = pen.miterLimit();
    const qreal dashOffset = pen.dashOffset();
    const QList<qreal> customDashPattern = pen.dashPattern();
    const Qt::PenStyle penStyle = pen.style();

    context.setStrokeAlpha(pen.color().alphaF());
    context.setStrokeWidth(width);
    context.setStrokeMiterLimit(miterLimit);

    switch (capStyle)
    {
    case Qt::FlatCap:
        context.setStrokeCaps(BL_STROKE_CAP_BUTT);
        break;
    case Qt::SquareCap:
        context.setStrokeCaps(BL_STROKE_CAP_SQUARE);
        break;
    case Qt::RoundCap:
        context.setStrokeCaps(BL_STROKE_CAP_ROUND);
        break;
    }

    BLArray<double> dashArray;

    for (double value : customDashPattern)
    {
        dashArray.append(value);
    }

    context.setStrokeDashOffset(dashOffset);
    context.setStrokeDashArray(dashArray);

    switch (joinStyle)
    {
    case Qt::MiterJoin:
        context.setStrokeJoin(BL_STROKE_JOIN_MITER_CLIP);
        break;
    case Qt::BevelJoin:
        context.setStrokeJoin(BL_STROKE_JOIN_BEVEL);
        break;
    case Qt::RoundJoin:
        context.setStrokeJoin(BL_STROKE_JOIN_ROUND);
        break;
    case Qt::SvgMiterJoin:
        context.setStrokeJoin(BL_STROKE_JOIN_MITER_CLIP);
        break;
    }

    context.setStrokeStyle(BLRgba32(color.rgba()));

    BLStrokeOptions strokeOptions = context.strokeOptions();

    switch (penStyle)
    {
    case Qt::SolidLine:
        strokeOptions.dashArray.clear();
        strokeOptions.dashOffset = 0.0;
        break;

    case Qt::DashLine:
    {
        constexpr double dashPattern[] = {4, 4};
        strokeOptions.dashArray.assignData(dashPattern, std::size(dashPattern));
        break;
    }

    case Qt::DotLine:
    {
        constexpr double dashPattern[] = {1, 3};
        strokeOptions.dashArray.assignData(dashPattern, std::size(dashPattern));
        break;
    }

    case Qt::DashDotLine:
    {
        constexpr double dashPattern[] = {4, 2, 1, 2};
        strokeOptions.dashArray.assignData(dashPattern, std::size(dashPattern));
        break;
    }

    case Qt::DashDotDotLine:
    {
        constexpr double dashPattern[] = {4, 2, 1, 2, 1, 2};
        strokeOptions.dashArray.assignData(dashPattern, std::size(dashPattern));
        break;
    }

    default:
        break;
    }

    context.setStrokeOptions(strokeOptions);
}

void PDFBLPaintEngine::setBLBrush(BLContext& context, const QBrush& brush)
{
    auto setGradientStops = [](BLGradient& blGradient, const auto& qGradient)
    {
        QVector<BLGradientStop> stops;
        for (const auto& stop : qGradient.stops())
        {
            stops.append(BLGradientStop(stop.first, BLRgba32(stop.second.red(), stop.second.green(), stop.second.blue(), stop.second.alpha())));
        }
        blGradient.assignStops(stops.constData(), stops.size());
    };

    switch (brush.style())
    {
        default:
        case Qt::SolidPattern:
        {
            QColor color = brush.color();
            BLRgba32 blColor = BLRgba32(color.red(), color.green(), color.blue(), color.alpha());
            context.setFillStyle(blColor);
            break;
        }
        case Qt::LinearGradientPattern:
        {
            const QGradient* gradient = brush.gradient();
            if (gradient && gradient->type() == QGradient::LinearGradient)
            {
                const QLinearGradient* linearGradient = static_cast<const QLinearGradient*>(gradient);
                BLLinearGradientValues blLinearGradient;
                blLinearGradient.x0 = linearGradient->start().x();
                blLinearGradient.y0 = linearGradient->start().y();
                blLinearGradient.x1 = linearGradient->finalStop().x();
                blLinearGradient.y1 = linearGradient->finalStop().y();
                BLGradient blGradient(blLinearGradient);
                setGradientStops(blGradient, *gradient);
                context.setFillStyle(blGradient);
            }
            break;
        }
        case Qt::RadialGradientPattern:
        {
            const QGradient* gradient = brush.gradient();
            if (gradient && gradient->type() == QGradient::RadialGradient)
            {
                const QRadialGradient* radialGradient = static_cast<const QRadialGradient*>(gradient);
                BLRadialGradientValues blRadialGradientValues;
                blRadialGradientValues.x0 = radialGradient->center().x();
                blRadialGradientValues.y0 = radialGradient->center().y();
                blRadialGradientValues.x1 = radialGradient->focalPoint().x();
                blRadialGradientValues.y1 = radialGradient->focalPoint().y();
                blRadialGradientValues.r0 = radialGradient->radius();
                BLGradient blGradient(blRadialGradientValues);
                setGradientStops(blGradient, *gradient);
                context.setFillStyle(blGradient);
            }
            break;
        }
    }
}

bool PDFBLPaintEngine::loadBLFont(BLFont& font, QString fontName, PDFReal fontSize)
{
    QByteArray data = PDFSystemFont::getFontData(fontName.toLatin1());

    BLFontData blFontData;
    if (blFontData.createFromData(data.data(), data.size()) == BL_SUCCESS)
    {
        BLFontFace fontFace;
        if (fontFace.createFromData(blFontData, 0) == BL_SUCCESS)
        {
            if (font.createFromFace(fontFace, fontSize) == BL_SUCCESS)
            {
                return true;
            }
        }
    }

    return false;
}

BLCompOp PDFBLPaintEngine::getBLCompOp(QPainter::CompositionMode mode)
{
    switch (mode)
    {
    case QPainter::CompositionMode_SourceOver:
        return BL_COMP_OP_SRC_OVER;
    case QPainter::CompositionMode_DestinationOver:
        return BL_COMP_OP_DST_OVER;
    case QPainter::CompositionMode_Clear:
        return BL_COMP_OP_CLEAR;
    case QPainter::CompositionMode_Source:
        return BL_COMP_OP_SRC_COPY;
    case QPainter::CompositionMode_Destination:
        return BL_COMP_OP_DST_COPY;
    case QPainter::CompositionMode_SourceIn:
        return BL_COMP_OP_SRC_IN;
    case QPainter::CompositionMode_DestinationIn:
        return BL_COMP_OP_DST_IN;
    case QPainter::CompositionMode_SourceOut:
        return BL_COMP_OP_SRC_OUT;
    case QPainter::CompositionMode_DestinationOut:
        return BL_COMP_OP_DST_OUT;
    case QPainter::CompositionMode_SourceAtop:
        return BL_COMP_OP_SRC_ATOP;
    case QPainter::CompositionMode_DestinationAtop:
        return BL_COMP_OP_DST_ATOP;
    case QPainter::CompositionMode_Xor:
        return BL_COMP_OP_XOR;
    case QPainter::CompositionMode_Plus:
        return BL_COMP_OP_PLUS;
    case QPainter::CompositionMode_Multiply:
        return BL_COMP_OP_MULTIPLY;
    case QPainter::CompositionMode_Screen:
        return BL_COMP_OP_SCREEN;
    case QPainter::CompositionMode_Overlay:
        return BL_COMP_OP_OVERLAY;
    case QPainter::CompositionMode_Darken:
        return BL_COMP_OP_DARKEN;
    case QPainter::CompositionMode_Lighten:
        return BL_COMP_OP_LIGHTEN;
    case QPainter::CompositionMode_ColorDodge:
        return BL_COMP_OP_COLOR_DODGE;
    case QPainter::CompositionMode_ColorBurn:
        return BL_COMP_OP_COLOR_BURN;
    case QPainter::CompositionMode_HardLight:
        return BL_COMP_OP_HARD_LIGHT;
    case QPainter::CompositionMode_SoftLight:
        return BL_COMP_OP_SOFT_LIGHT;
    case QPainter::CompositionMode_Difference:
        return BL_COMP_OP_DIFFERENCE;
    case QPainter::CompositionMode_Exclusion:
        return BL_COMP_OP_EXCLUSION;
    default:
        break;
    }

    return BL_COMP_OP_SRC_OVER;
}

void PDFBLPaintEngine::setPathFillMode(PolygonDrawMode mode, QPainterPath& path)
{
    switch (mode)
    {
    case QPaintEngine::OddEvenMode:
        path.setFillRule(Qt::OddEvenFill);
        break;
    case QPaintEngine::WindingMode:
        path.setFillRule(Qt::WindingFill);
        break;
    case QPaintEngine::ConvexMode:
        path.setFillRule(Qt::OddEvenFill);
        break;
    case QPaintEngine::PolylineMode:
        path.setFillRule(Qt::OddEvenFill);
        break;
    }
}

void PDFBLPaintEngine::updateClipping(std::optional<QRegion> clipRegion,
                                      std::optional<QPainterPath> clipPath,
                                      Qt::ClipOperation clipOperation)
{
    QPainterPath finalClipPath;

    if (clipRegion.has_value())
    {
        finalClipPath.addRegion(clipRegion.value());
    }

    if (clipPath.has_value())
    {
        finalClipPath.addPath(clipPath.value());
    }

    finalClipPath = m_currentTransform.map(finalClipPath);

    switch (clipOperation)
    {
        case Qt::NoClip:
            m_finalClipPath.reset();
            m_finalClipPathBoundingBox = QRectF();
            m_clipSingleRect = false;
            m_blContext->restoreClipping();
            return;

        case Qt::ReplaceClip:
        {
            m_finalClipPath = std::move(finalClipPath);
            break;
        }

        case Qt::IntersectClip:
        {
            if (m_finalClipPath.has_value())
            {
                m_finalClipPath = m_finalClipPath->intersected(finalClipPath);
            }
            else
            {
                m_finalClipPath = std::move(finalClipPath);
            }
            break;
        }
    }

    m_clipSingleRect = false;
    m_finalClipPathBoundingBox = m_finalClipPath->controlPointRect();

    if (m_finalClipPath->elementCount() == 5)
    {
        QRectF testRect = m_finalClipPathBoundingBox.adjusted(1.0, 1.0, -2.0, -2.0);
        m_clipSingleRect = m_finalClipPath->contains(testRect);
    }

    if (m_clipSingleRect)
    {
        BLMatrix2D matrix = m_blContext->userMatrix();
        m_blContext->resetMatrix();
        m_blContext->clipToRect(getBLRect(m_finalClipPath->boundingRect()));
        m_blContext->setMatrix(matrix);
    }
    else
    {
        m_blContext->restoreClipping();
    }
}

PDFBLPaintEngine::ClipMode PDFBLPaintEngine::resolveClipping(const QLineF& line) const
{
    if (!m_currentIsClipEnabled || m_clipSingleRect || !m_finalClipPath.has_value())
    {
        return ClipMode::NoClip;
    }

    if (m_finalClipPath->isEmpty())
    {
        return ClipMode::NotVisible;
    }

    QRectF clipRect = m_finalClipPathBoundingBox;

    qreal minX = qMin(line.x1(), line.x2());
    qreal maxX = qMax(line.x1(), line.x2());
    qreal minY = qMin(line.y1(), line.y2());
    qreal maxY = qMax(line.y1(), line.y2());

    QRectF rect(minX, minY, maxX - minX + 1.0, maxY - minY + 1.0);

    if (!rect.intersects(clipRect))
    {
        return ClipMode::NotVisible;
    }

    return ClipMode::NeedsResolve;
}

PDFBLPaintEngine::ClipMode PDFBLPaintEngine::resolveClipping(const QPointF& point) const
{
    if (!m_currentIsClipEnabled || m_clipSingleRect || !m_finalClipPath.has_value())
    {
        return ClipMode::NoClip;
    }

    if (m_finalClipPath->isEmpty())
    {
        return ClipMode::NotVisible;
    }

    if (!m_finalClipPath->contains(point))
    {
        return ClipMode::NotVisible;
    }

    return ClipMode::NoClip;
}

PDFBLPaintEngine::ClipMode PDFBLPaintEngine::resolveClipping(const QRectF& rect) const
{
    if (!m_currentIsClipEnabled || m_clipSingleRect || !m_finalClipPath.has_value())
    {
        return ClipMode::NoClip;
    }

    if (m_finalClipPath->isEmpty())
    {
        return ClipMode::NotVisible;
    }

    QRectF clipRect = m_finalClipPathBoundingBox;

    if (!rect.intersects(clipRect))
    {
        return ClipMode::NotVisible;
    }

    return ClipMode::NeedsResolve;
}

PDFBLPaintEngine::ClipMode PDFBLPaintEngine::resolveClipping(const QPainterPath& path) const
{
    if (!m_currentIsClipEnabled || m_clipSingleRect || !m_finalClipPath.has_value())
    {
        return ClipMode::NoClip;
    }

    if (m_finalClipPath->isEmpty())
    {
        return ClipMode::NotVisible;
    }

    QRectF clipRect = m_finalClipPathBoundingBox;
    QRectF pathRect = path.controlPointRect();

    if (!pathRect.intersects(clipRect))
    {
        return ClipMode::NotVisible;
    }

    return ClipMode::NeedsResolve;
}

void PDFBLPaintEngine::setFillRule(Qt::FillRule fillRule)
{
    BLFillRule blFillRule{};

    switch (fillRule)
    {
    case Qt::OddEvenFill:
        blFillRule = BL_FILL_RULE_EVEN_ODD;
        break;

    case Qt::WindingFill:
        blFillRule = BL_FILL_RULE_NON_ZERO;
        break;

    default:
        Q_ASSERT(false);
        break;
    }

    m_blContext->setFillRule(blFillRule);
}

}   // namespace pdf