//    Copyright (C) 2019-2020 Jakub Melka
//
//    This file is part of PdfForQt.
//
//    PdfForQt 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
//    (at your option) any later version.
//
//    PdfForQt 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 PDFForQt.  If not, see <https://www.gnu.org/licenses/>.

#include "pdfpainter.h"
#include "pdfpattern.h"

#include <QPainter>

namespace pdf
{

PDFPainterBase::PDFPainterBase(PDFRenderer::Features features,
                               const PDFPage* page,
                               const PDFDocument* document,
                               const PDFFontCache* fontCache,
                               const PDFCMS* cms,
                               const PDFOptionalContentActivity* optionalContentActivity,
                               QMatrix pagePointToDevicePointMatrix,
                               const PDFMeshQualitySettings& meshQualitySettings) :
    BaseClass(page, document, fontCache, cms, optionalContentActivity, pagePointToDevicePointMatrix, meshQualitySettings),
    m_features(features)
{

}

void PDFPainterBase::performUpdateGraphicsState(const PDFPageContentProcessorState& state)
{
    const PDFPageContentProcessorState::StateFlags flags = state.getStateFlags();

    // If current transformation matrix has changed, then update it
    if (flags.testFlag(PDFPageContentProcessorState::StateCurrentTransformationMatrix))
    {
        setWorldMatrix(getCurrentWorldMatrix());
    }

    if (flags.testFlag(PDFPageContentProcessorState::StateStrokeColor) ||
        flags.testFlag(PDFPageContentProcessorState::StateLineWidth) ||
        flags.testFlag(PDFPageContentProcessorState::StateLineCapStyle) ||
        flags.testFlag(PDFPageContentProcessorState::StateLineJoinStyle) ||
        flags.testFlag(PDFPageContentProcessorState::StateMitterLimit) ||
        flags.testFlag(PDFPageContentProcessorState::StateLineDashPattern) ||
        flags.testFlag(PDFPageContentProcessorState::StateAlphaStroking))
    {
        m_currentPen.dirty();
    }

    if (flags.testFlag(PDFPageContentProcessorState::StateFillColor) ||
        flags.testFlag(PDFPageContentProcessorState::StateAlphaFilling))
    {
        m_currentBrush.dirty();
    }

    // If current blend mode has changed, then update it
    if (flags.testFlag(PDFPageContentProcessorState::StateBlendMode))
    {
        // Try to simulate transparency groups. Use only first composition mode,
        // outside the transparency groups (so we are on pages main transparency
        // groups).

        const BlendMode blendMode = state.getBlendMode();
        if (canSetBlendMode(blendMode))
        {
            if (!PDFBlendModeInfo::isSupportedByQt(blendMode))
            {
                reportRenderErrorOnce(RenderErrorType::NotSupported, PDFTranslationContext::tr("Blend mode '%1' not supported.").arg(PDFBlendModeInfo::getBlendModeName(blendMode)));
            }

            const QPainter::CompositionMode compositionMode = PDFBlendModeInfo::getCompositionModeFromBlendMode(blendMode);
            setCompositionMode(compositionMode);
        }
        else if (blendMode != BlendMode::Normal && blendMode != BlendMode::Compatible)
        {
            reportRenderErrorOnce(RenderErrorType::NotSupported, PDFTranslationContext::tr("Blend mode '%1' is in transparency group, which is not supported.").arg(PDFBlendModeInfo::getBlendModeName(blendMode)));
        }
    }

    BaseClass::performUpdateGraphicsState(state);
}

bool PDFPainterBase::isContentSuppressedByOC(PDFObjectReference ocgOrOcmd)
{
    if (m_features.testFlag(PDFRenderer::IgnoreOptionalContent))
    {
        return false;
    }

    return PDFPageContentProcessor::isContentSuppressedByOC(ocgOrOcmd);
}

QPen PDFPainterBase::getCurrentPenImpl() const
{
    const PDFPageContentProcessorState* graphicState = getGraphicState();
    QColor color = graphicState->getStrokeColor();
    if (color.isValid())
    {
        color.setAlphaF(getEffectiveStrokingAlpha());
        const PDFReal lineWidth = graphicState->getLineWidth();
        Qt::PenCapStyle penCapStyle = graphicState->getLineCapStyle();
        Qt::PenJoinStyle penJoinStyle = graphicState->getLineJoinStyle();
        const PDFLineDashPattern& lineDashPattern = graphicState->getLineDashPattern();
        const PDFReal mitterLimit = graphicState->getMitterLimit();

        QPen pen(color);

        pen.setWidthF(lineWidth);
        pen.setCapStyle(penCapStyle);
        pen.setJoinStyle(penJoinStyle);
        pen.setMiterLimit(mitterLimit);

        if (lineDashPattern.isSolid())
        {
            pen.setStyle(Qt::SolidLine);
        }
        else
        {
            pen.setStyle(Qt::CustomDashLine);
            pen.setDashPattern(QVector<PDFReal>::fromStdVector(lineDashPattern.getDashArray()));
            pen.setDashOffset(lineDashPattern.getDashOffset());
        }

        return pen;
    }
    else
    {
        return QPen(Qt::NoPen);
    }
}

QBrush PDFPainterBase::getCurrentBrushImpl() const
{
    const PDFPageContentProcessorState* graphicState = getGraphicState();
    QColor color = graphicState->getFillColor();
    if (color.isValid())
    {
        color.setAlphaF(getEffectiveFillingAlpha());
        return QBrush(color, Qt::SolidPattern);
    }
    else
    {
        return QBrush(Qt::NoBrush);
    }
}

PDFReal PDFPainterBase::getEffectiveStrokingAlpha() const
{
    PDFReal alpha = getGraphicState()->getAlphaStroking();

    auto it = m_transparencyGroupDataStack.crbegin();
    auto itEnd = m_transparencyGroupDataStack.crend();
    for (; it != itEnd; ++it)
    {
        const PDFTransparencyGroupPainterData& transparencyGroup = *it;
        alpha *= transparencyGroup.alphaStroke;

        if (transparencyGroup.group.isolated)
        {
            break;
        }
    }

    return alpha;
}

PDFReal PDFPainterBase::getEffectiveFillingAlpha() const
{
    PDFReal alpha = getGraphicState()->getAlphaFilling();

    auto it = m_transparencyGroupDataStack.crbegin();
    auto itEnd = m_transparencyGroupDataStack.crend();
    for (; it != itEnd; ++it)
    {
        const PDFTransparencyGroupPainterData& transparencyGroup = *it;
        alpha *= transparencyGroup.alphaFill;

        if (transparencyGroup.group.isolated)
        {
            break;
        }
    }

    return alpha;
}

bool PDFPainterBase::canSetBlendMode(BlendMode mode) const
{
    // We will assume, that we can set blend mode, when
    // all other blend modes on transparency stack are normal,
    // or compatible. It should work.

    Q_UNUSED(mode);
    return std::all_of(m_transparencyGroupDataStack.cbegin(), m_transparencyGroupDataStack.cend(), [](const PDFTransparencyGroupPainterData& group) { return group.blendMode == BlendMode::Normal || group.blendMode == BlendMode::Compatible; });
}

void PDFPainterBase::performBeginTransparencyGroup(ProcessOrder order, const PDFTransparencyGroup& transparencyGroup)
{
    if (order == ProcessOrder::BeforeOperation)
    {
        PDFTransparencyGroupPainterData data;
        data.group = transparencyGroup;
        data.alphaFill = getGraphicState()->getAlphaFilling();
        data.alphaStroke = getGraphicState()->getAlphaStroking();
        data.blendMode = getGraphicState()->getBlendMode();
        m_transparencyGroupDataStack.emplace_back(qMove(data));
    }
}

void PDFPainterBase::performEndTransparencyGroup(ProcessOrder order, const PDFTransparencyGroup& transparencyGroup)
{
    Q_UNUSED(transparencyGroup);

    if (order == ProcessOrder::AfterOperation)
    {
        m_transparencyGroupDataStack.pop_back();
    }
}

PDFPainter::PDFPainter(QPainter* painter,
                       PDFRenderer::Features features,
                       QMatrix pagePointToDevicePointMatrix,
                       const PDFPage* page,
                       const PDFDocument* document,
                       const PDFFontCache* fontCache,
                       const PDFCMS* cms,
                       const PDFOptionalContentActivity* optionalContentActivity,
                       const PDFMeshQualitySettings& meshQualitySettings) :
    BaseClass(features, page, document, fontCache, cms, optionalContentActivity, pagePointToDevicePointMatrix, meshQualitySettings),
    m_painter(painter)
{
    Q_ASSERT(painter);
    Q_ASSERT(pagePointToDevicePointMatrix.isInvertible());

    m_painter->save();

    if (features.testFlag(PDFRenderer::ClipToCropBox))
    {
        QRectF cropBox = page->getCropBox();
        if (cropBox.isValid())
        {
            QPainterPath path;
            path.addPolygon(pagePointToDevicePointMatrix.map(cropBox));

            m_painter->setClipPath(path, Qt::IntersectClip);
        }
    }

    m_painter->setRenderHint(QPainter::SmoothPixmapTransform, features.testFlag(PDFRenderer::SmoothImages));
}

PDFPainter::~PDFPainter()
{
    m_painter->restore();
}

void PDFPainter::performPathPainting(const QPainterPath& path, bool stroke, bool fill, bool text, Qt::FillRule fillRule)
{
    Q_ASSERT(stroke || fill);

    // Set antialiasing
    const bool antialiasing = (text && hasFeature(PDFRenderer::TextAntialiasing)) || (!text && hasFeature(PDFRenderer::Antialiasing));
    m_painter->setRenderHint(QPainter::Antialiasing, antialiasing);

    if (stroke)
    {
        m_painter->setPen(getCurrentPen());
    }
    else
    {
        m_painter->setPen(Qt::NoPen);
    }

    if (fill)
    {
        m_painter->setBrush(getCurrentBrush());
    }
    else
    {
        m_painter->setBrush(Qt::NoBrush);
    }

    Q_ASSERT(path.fillRule() == fillRule);
    m_painter->drawPath(path);
}

void PDFPainter::performClipping(const QPainterPath& path, Qt::FillRule fillRule)
{
    Q_ASSERT(path.fillRule() == fillRule);
    m_painter->setClipPath(path, Qt::IntersectClip);
}

void PDFPainter::performImagePainting(const QImage& image)
{
    if (isContentSuppressed())
    {
        // Content is suppressed, do not paint anything
        return;
    }

    m_painter->save();

    QImage adjustedImage = image;

    if (hasFeature(PDFRenderer::SmoothImages))
    {
        // Test, if we can use smooth images. We can use them under following conditions:
        //  1) Transformed rectangle is not skewed or deformed (so vectors (0, 1) and (1, 0) are orthogonal)
        //  2) Image enlargement is not too big (so we doesn't run out of memory)

        QMatrix matrix = m_painter->worldMatrix();
        QLineF mappedWidthVector = matrix.map(QLineF(0, 0, 1, 0));
        QLineF mappedHeightVector = matrix.map(QLineF(0, 0, 0, 1));
        qreal angle = mappedWidthVector.angleTo(mappedHeightVector);
        if (qFuzzyCompare(angle, 90.0))
        {
            // Image is not skewed, so we test enlargement factor
            const int newWidth = mappedWidthVector.length();
            const int newHeight = mappedHeightVector.length();

            const int newPixels = newWidth * newHeight;
            const int oldPixels = image.width() * image.height();

            if (newPixels < oldPixels * 8)
            {
                QSize size = adjustedImage.size();
                QSize adjustedImageSize = size.scaled(newWidth, newHeight, Qt::KeepAspectRatio);
                adjustedImage = adjustedImage.scaled(adjustedImageSize, Qt::KeepAspectRatio, Qt::SmoothTransformation);
            }
        }
    }

    QMatrix imageTransform(1.0 / adjustedImage.width(), 0, 0, 1.0 / adjustedImage.height(), 0, 0);
    QMatrix worldMatrix = imageTransform * m_painter->worldMatrix();

    // Because Qt uses opposite axis direction than PDF, then we must transform the y-axis
    // to the opposite (so the image is then unchanged)
    worldMatrix.translate(0, adjustedImage.height());
    worldMatrix.scale(1, -1);

    m_painter->setWorldMatrix(worldMatrix);
    m_painter->drawImage(0, 0, adjustedImage);

    m_painter->restore();
}

void PDFPainter::performMeshPainting(const PDFMesh& mesh)
{
    m_painter->save();
    m_painter->setWorldMatrix(QMatrix());
    mesh.paint(m_painter, getEffectiveFillingAlpha());
    m_painter->restore();
}

void PDFPainter::performSaveGraphicState(ProcessOrder order)
{
    if (order == ProcessOrder::AfterOperation)
    {
        m_painter->save();
    }
}

void PDFPainter::performRestoreGraphicState(ProcessOrder order)
{
    if (order == ProcessOrder::BeforeOperation)
    {
        m_painter->restore();
    }
}

void PDFPainter::setWorldMatrix(const QMatrix& matrix)
{
    m_painter->setWorldMatrix(matrix, false);
}

void PDFPainter::setCompositionMode(QPainter::CompositionMode mode)
{
    m_painter->setCompositionMode(mode);
}

void PDFPrecompiledPageGenerator::performPathPainting(const QPainterPath& path, bool stroke, bool fill, bool text, Qt::FillRule fillRule)
{
    Q_ASSERT(stroke || fill);
    Q_ASSERT(path.fillRule() == fillRule);

    QPen pen = stroke ? getCurrentPen() : QPen(Qt::NoPen);
    QBrush brush = fill ? getCurrentBrush() : QBrush(Qt::NoBrush);
    m_precompiledPage->addPath(qMove(pen), qMove(brush), path, text);
}

void PDFPrecompiledPageGenerator::performClipping(const QPainterPath& path, Qt::FillRule fillRule)
{
    Q_ASSERT(path.fillRule() == fillRule);
    m_precompiledPage->addClip(path);
}

void PDFPrecompiledPageGenerator::performImagePainting(const QImage& image)
{
    if (isContentSuppressed())
    {
        // Content is suppressed, do not paint anything
        return;
    }

    if (isTransparencyGroupActive())
    {
        PDFReal alpha = getEffectiveFillingAlpha();
        if (alpha != 1.0)
        {
            // Try to approximate transparency group using alpha channel
            QImage imageWithAlpha = image;
            QImage alphaChannel = imageWithAlpha.convertToFormat(QImage::Format_Alpha8);
            uchar* bits = alphaChannel.bits();

            for (qsizetype i = 0, sizeInBytes = alphaChannel.sizeInBytes(); i < sizeInBytes; ++i)
            {
                bits[i] *= alpha;
            }

            imageWithAlpha.setAlphaChannel(alphaChannel);
            m_precompiledPage->addImage(imageWithAlpha);
            return;
        }
    }

    m_precompiledPage->addImage(image);
}

void PDFPrecompiledPageGenerator::performMeshPainting(const PDFMesh& mesh)
{
    m_precompiledPage->addMesh(mesh, getEffectiveFillingAlpha());
}

void PDFPrecompiledPageGenerator::performSaveGraphicState(PDFPageContentProcessor::ProcessOrder order)
{
    if (order == ProcessOrder::AfterOperation)
    {
        m_precompiledPage->addSaveGraphicState();
    }
}

void PDFPrecompiledPageGenerator::performRestoreGraphicState(PDFPageContentProcessor::ProcessOrder order)
{
    if (order == ProcessOrder::BeforeOperation)
    {
        m_precompiledPage->addRestoreGraphicState();
    }
}

void PDFPrecompiledPageGenerator::setWorldMatrix(const QMatrix& matrix)
{
    m_precompiledPage->addSetWorldMatrix(matrix);
}

void PDFPrecompiledPageGenerator::setCompositionMode(QPainter::CompositionMode mode)
{
    m_precompiledPage->addSetCompositionMode(mode);
}

void PDFPrecompiledPage::draw(QPainter* painter, const QRectF& cropBox, const QMatrix& pagePointToDevicePointMatrix, PDFRenderer::Features features) const
{
    Q_ASSERT(painter);
    Q_ASSERT(pagePointToDevicePointMatrix.isInvertible());

    painter->save();

    if (features.testFlag(PDFRenderer::ClipToCropBox))
    {
        if (cropBox.isValid())
        {
            QPainterPath path;
            path.addPolygon(pagePointToDevicePointMatrix.map(cropBox));
            painter->setClipPath(path, Qt::IntersectClip);
        }
    }

    painter->setRenderHint(QPainter::SmoothPixmapTransform, features.testFlag(PDFRenderer::SmoothImages));

    // Process all instructions
    for (const Instruction& instruction : m_instructions)
    {
        switch (instruction.type)
        {
            case InstructionType::DrawPath:
            {
                const PathPaintData& data = m_paths[instruction.dataIndex];

                // Set antialiasing
                const bool antialiasing = (data.isText && features.testFlag(PDFRenderer::TextAntialiasing)) || (!data.isText && features.testFlag(PDFRenderer::Antialiasing));
                painter->setRenderHint(QPainter::Antialiasing, antialiasing);
                painter->setPen(data.pen);
                painter->setBrush(data.brush);
                painter->drawPath(data.path);
                break;
            }

            case InstructionType::DrawImage:
            {
                const ImageData& data = m_images[instruction.dataIndex];
                const QImage& image = data.image;

                painter->save();

                QMatrix imageTransform(1.0 / image.width(), 0, 0, 1.0 / image.height(), 0, 0);
                QMatrix worldMatrix = imageTransform * painter->worldMatrix();

                // Jakub Melka: Because Qt uses opposite axis direction than PDF, then we must transform the y-axis
                // to the opposite (so the image is then unchanged)
                worldMatrix.translate(0, image.height());
                worldMatrix.scale(1, -1);

                painter->setWorldMatrix(worldMatrix);
                painter->drawImage(0, 0, image);
                painter->restore();
                break;
            }

            case InstructionType::DrawMesh:
            {
                const MeshPaintData& data = m_meshes[instruction.dataIndex];

                painter->save();
                painter->setWorldMatrix(pagePointToDevicePointMatrix);
                data.mesh.paint(painter, data.alpha);
                painter->restore();
                break;
            }

            case InstructionType::Clip:
            {
                painter->setClipPath(m_clips[instruction.dataIndex].clipPath, Qt::IntersectClip);
                break;
            }

            case InstructionType::SaveGraphicState:
            {
                painter->save();
                break;
            }

            case InstructionType::RestoreGraphicState:
            {
                painter->restore();
                break;
            }

            case InstructionType::SetWorldMatrix:
            {
                painter->setWorldMatrix(m_matrices[instruction.dataIndex] * pagePointToDevicePointMatrix);
                break;
            }

            case InstructionType::SetCompositionMode:
            {
                painter->setCompositionMode(m_compositionModes[instruction.dataIndex]);
                break;
            }

            default:
            {
                Q_ASSERT(false);
                break;
            }
        }
    }

    painter->restore();
}

void PDFPrecompiledPage::addPath(QPen pen, QBrush brush, QPainterPath path, bool isText)
{
    m_instructions.emplace_back(InstructionType::DrawPath, m_paths.size());
    m_paths.emplace_back(qMove(pen), qMove(brush), qMove(path), isText);
}

void PDFPrecompiledPage::addClip(QPainterPath path)
{
    m_instructions.emplace_back(InstructionType::Clip, m_clips.size());
    m_clips.emplace_back(qMove(path));
}

void PDFPrecompiledPage::addImage(QImage image)
{
    // Convert the image into format Format_ARGB32_Premultiplied for fast drawing.
    // If this format is used, then no image conversion is performed while drawing.
    if (image.format() != QImage::Format_ARGB32_Premultiplied)
    {
        image.convertTo(QImage::Format_ARGB32_Premultiplied);
    }

    m_instructions.emplace_back(InstructionType::DrawImage, m_images.size());
    m_images.emplace_back(qMove(image));
}

void PDFPrecompiledPage::addMesh(PDFMesh mesh, PDFReal alpha)
{
    m_instructions.emplace_back(InstructionType::DrawMesh, m_meshes.size());
    m_meshes.emplace_back(qMove(mesh), alpha);
}

void PDFPrecompiledPage::addSetWorldMatrix(const QMatrix& matrix)
{
    m_instructions.emplace_back(InstructionType::SetWorldMatrix, m_matrices.size());
    m_matrices.push_back(matrix);
}

void PDFPrecompiledPage::addSetCompositionMode(QPainter::CompositionMode compositionMode)
{
    m_instructions.emplace_back(InstructionType::SetCompositionMode, m_compositionModes.size());
    m_compositionModes.push_back(compositionMode);
}

void PDFPrecompiledPage::optimize()
{
    m_instructions.shrink_to_fit();
    m_paths.shrink_to_fit();
    m_clips.shrink_to_fit();
    m_images.shrink_to_fit();
    m_meshes.shrink_to_fit();
    m_matrices.shrink_to_fit();
    m_compositionModes.shrink_to_fit();
}

void PDFPrecompiledPage::finalize(qint64 compilingTimeNS, QList<PDFRenderError> errors)
{
    m_compilingTimeNS = compilingTimeNS;
    m_errors = qMove(errors);

    // Determine memory consumption
    m_memoryConsumptionEstimate = sizeof(*this);
    m_memoryConsumptionEstimate += sizeof(Instruction) * m_instructions.capacity();
    m_memoryConsumptionEstimate += sizeof(PathPaintData) * m_paths.capacity();
    m_memoryConsumptionEstimate += sizeof(ClipData) * m_clips.capacity();
    m_memoryConsumptionEstimate += sizeof(ImageData) * m_images.capacity();
    m_memoryConsumptionEstimate += sizeof(MeshPaintData) * m_meshes.capacity();
    m_memoryConsumptionEstimate += sizeof(QMatrix) * m_matrices.capacity();
    m_memoryConsumptionEstimate += sizeof(QPainter::CompositionMode) * m_compositionModes.capacity();
    m_memoryConsumptionEstimate += sizeof(PDFRenderError) * m_errors.size();

    auto calculateQPathMemoryConsumption = [](const QPainterPath& path)
    {
        return sizeof(QPainterPath::Element) * path.capacity();
    };
    for (const PathPaintData& data : m_paths)
    {
        // Texts are shared from the font
        if (!data.isText)
        {
            m_memoryConsumptionEstimate += calculateQPathMemoryConsumption(data.path);
        }
    }
    for (const ClipData& data : m_clips)
    {
        m_memoryConsumptionEstimate += calculateQPathMemoryConsumption(data.clipPath);
    }
    for (const ImageData& data : m_images)
    {
        m_memoryConsumptionEstimate += data.image.sizeInBytes();
    }
    for (const MeshPaintData& data : m_meshes)
    {
        m_memoryConsumptionEstimate += data.mesh.getMemoryConsumptionEstimate();
    }
}

}   // namespace pdf