/*
  ==============================================================================

   This file is part of the JUCE 6 technical preview.
   Copyright (c) 2020 - Raw Material Software Limited

   You may use this code under the terms of the GPL v3
   (see www.gnu.org/licenses).

   For this technical preview, this file is not subject to commercial licensing.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

ImagePixelData::ImagePixelData (Image::PixelFormat format, int w, int h)
    : pixelFormat (format), width (w), height (h)
{
    jassert (format == Image::RGB || format == Image::ARGB || format == Image::SingleChannel);
    jassert (w > 0 && h > 0); // It's illegal to create a zero-sized image!
}

ImagePixelData::~ImagePixelData()
{
    listeners.call ([this] (Listener& l) { l.imageDataBeingDeleted (this); });
}

void ImagePixelData::sendDataChangeMessage()
{
    listeners.call ([this] (Listener& l) { l.imageDataChanged (this); });
}

int ImagePixelData::getSharedCount() const noexcept
{
    return getReferenceCount();
}

//==============================================================================
ImageType::ImageType() {}
ImageType::~ImageType() {}

Image ImageType::convert (const Image& source) const
{
    if (source.isNull() || getTypeID() == source.getPixelData()->createType()->getTypeID())
        return source;

    const Image::BitmapData src (source, Image::BitmapData::readOnly);

    Image newImage (create (src.pixelFormat, src.width, src.height, false));
    Image::BitmapData dest (newImage, Image::BitmapData::writeOnly);

    if (src.pixelStride == dest.pixelStride && src.pixelFormat == dest.pixelFormat)
    {
        for (int y = 0; y < dest.height; ++y)
            memcpy (dest.getLinePointer (y), src.getLinePointer (y), (size_t) dest.lineStride);
    }
    else
    {
        for (int y = 0; y < dest.height; ++y)
            for (int x = 0; x < dest.width; ++x)
                dest.setPixelColour (x, y, src.getPixelColour (x, y));
    }

    return newImage;
}

//==============================================================================
class SoftwarePixelData  : public ImagePixelData
{
public:
    SoftwarePixelData (Image::PixelFormat formatToUse, int w, int h, bool clearImage)
        : ImagePixelData (formatToUse, w, h),
          pixelStride (formatToUse == Image::RGB ? 3 : ((formatToUse == Image::ARGB) ? 4 : 1)),
          lineStride ((pixelStride * jmax (1, w) + 3) & ~3)
    {
        imageData.allocate ((size_t) lineStride * (size_t) jmax (1, h), clearImage);
    }

    std::unique_ptr<LowLevelGraphicsContext> createLowLevelContext() override
    {
        sendDataChangeMessage();
        return std::make_unique<LowLevelGraphicsSoftwareRenderer> (Image (*this));
    }

    void initialiseBitmapData (Image::BitmapData& bitmap, int x, int y, Image::BitmapData::ReadWriteMode mode) override
    {
        bitmap.data = imageData + (size_t) x * (size_t) pixelStride + (size_t) y * (size_t) lineStride;
        bitmap.pixelFormat = pixelFormat;
        bitmap.lineStride = lineStride;
        bitmap.pixelStride = pixelStride;

        if (mode != Image::BitmapData::readOnly)
            sendDataChangeMessage();
    }

    ImagePixelData::Ptr clone() override
    {
        auto s = new SoftwarePixelData (pixelFormat, width, height, false);
        memcpy (s->imageData, imageData, (size_t) lineStride * (size_t) height);
        return *s;
    }

    std::unique_ptr<ImageType> createType() const override    { return std::make_unique<SoftwareImageType>(); }

private:
    HeapBlock<uint8> imageData;
    const int pixelStride, lineStride;

    JUCE_LEAK_DETECTOR (SoftwarePixelData)
};

SoftwareImageType::SoftwareImageType() {}
SoftwareImageType::~SoftwareImageType() {}

ImagePixelData::Ptr SoftwareImageType::create (Image::PixelFormat format, int width, int height, bool clearImage) const
{
    return *new SoftwarePixelData (format, width, height, clearImage);
}

int SoftwareImageType::getTypeID() const
{
    return 2;
}

//==============================================================================
NativeImageType::NativeImageType() {}
NativeImageType::~NativeImageType() {}

int NativeImageType::getTypeID() const
{
    return 1;
}

#if JUCE_WINDOWS || JUCE_LINUX
ImagePixelData::Ptr NativeImageType::create (Image::PixelFormat format, int width, int height, bool clearImage) const
{
    return new SoftwarePixelData (format, width, height, clearImage);
}
#endif

//==============================================================================
class SubsectionPixelData  : public ImagePixelData
{
public:
    SubsectionPixelData (ImagePixelData::Ptr source, Rectangle<int> r)
        : ImagePixelData (source->pixelFormat, r.getWidth(), r.getHeight()),
          sourceImage (std::move (source)), area (r)
    {
    }

    std::unique_ptr<LowLevelGraphicsContext> createLowLevelContext() override
    {
        auto g = sourceImage->createLowLevelContext();
        g->clipToRectangle (area);
        g->setOrigin (area.getPosition());
        return g;
    }

    void initialiseBitmapData (Image::BitmapData& bitmap, int x, int y, Image::BitmapData::ReadWriteMode mode) override
    {
        sourceImage->initialiseBitmapData (bitmap, x + area.getX(), y + area.getY(), mode);

        if (mode != Image::BitmapData::readOnly)
            sendDataChangeMessage();
    }

    ImagePixelData::Ptr clone() override
    {
        jassert (getReferenceCount() > 0); // (This method can't be used on an unowned pointer, as it will end up self-deleting)
        auto type = createType();

        Image newImage (type->create (pixelFormat, area.getWidth(), area.getHeight(), pixelFormat != Image::RGB));

        {
            Graphics g (newImage);
            g.drawImageAt (Image (*this), 0, 0);
        }

        return *newImage.getPixelData();
    }

    std::unique_ptr<ImageType> createType() const override          { return sourceImage->createType(); }

    /* as we always hold a reference to image, don't double count */
    int getSharedCount() const noexcept override    { return getReferenceCount() + sourceImage->getSharedCount() - 1; }

private:
    friend class Image;
    const ImagePixelData::Ptr sourceImage;
    const Rectangle<int> area;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (SubsectionPixelData)
};

Image Image::getClippedImage (const Rectangle<int>& area) const
{
    if (area.contains (getBounds()))
        return *this;

    auto validArea = area.getIntersection (getBounds());

    if (validArea.isEmpty())
        return {};

    return Image (*new SubsectionPixelData (image, validArea));
}


//==============================================================================
Image::Image() noexcept
{
}

Image::Image (ReferenceCountedObjectPtr<ImagePixelData> instance) noexcept
    : image (std::move (instance))
{
}

Image::Image (PixelFormat format, int width, int height, bool clearImage)
    : image (NativeImageType().create (format, width, height, clearImage))
{
}

Image::Image (PixelFormat format, int width, int height, bool clearImage, const ImageType& type)
    : image (type.create (format, width, height, clearImage))
{
}

Image::Image (const Image& other) noexcept
    : image (other.image)
{
}

Image& Image::operator= (const Image& other)
{
    image = other.image;
    return *this;
}

Image::Image (Image&& other) noexcept
    : image (std::move (other.image))
{
}

Image& Image::operator= (Image&& other) noexcept
{
    image = std::move (other.image);
    return *this;
}

Image::~Image()
{
}

JUCE_DECLARE_DEPRECATED_STATIC (const Image Image::null;)

int Image::getReferenceCount() const noexcept           { return image == nullptr ? 0 : image->getSharedCount(); }
int Image::getWidth() const noexcept                    { return image == nullptr ? 0 : image->width; }
int Image::getHeight() const noexcept                   { return image == nullptr ? 0 : image->height; }
Rectangle<int> Image::getBounds() const noexcept        { return image == nullptr ? Rectangle<int>() : Rectangle<int> (image->width, image->height); }
Image::PixelFormat Image::getFormat() const noexcept    { return image == nullptr ? UnknownFormat : image->pixelFormat; }
bool Image::isARGB() const noexcept                     { return getFormat() == ARGB; }
bool Image::isRGB() const noexcept                      { return getFormat() == RGB; }
bool Image::isSingleChannel() const noexcept            { return getFormat() == SingleChannel; }
bool Image::hasAlphaChannel() const noexcept            { return getFormat() != RGB; }

std::unique_ptr<LowLevelGraphicsContext> Image::createLowLevelContext() const
{
    if (image != nullptr)
        return image->createLowLevelContext();

    return {};
}

void Image::duplicateIfShared()
{
    if (getReferenceCount() > 1)
        image = image->clone();
}

Image Image::createCopy() const
{
    if (image != nullptr)
        return Image (image->clone());

    return {};
}

Image Image::rescaled (int newWidth, int newHeight, Graphics::ResamplingQuality quality) const
{
    if (image == nullptr || (image->width == newWidth && image->height == newHeight))
        return *this;

    auto type = image->createType();
    Image newImage (type->create (image->pixelFormat, newWidth, newHeight, hasAlphaChannel()));

    Graphics g (newImage);
    g.setImageResamplingQuality (quality);
    g.drawImageTransformed (*this, AffineTransform::scale (newWidth  / (float) image->width,
                                                           newHeight / (float) image->height), false);
    return newImage;
}

Image Image::convertedToFormat (PixelFormat newFormat) const
{
    if (image == nullptr || newFormat == image->pixelFormat)
        return *this;

    auto w = image->width, h = image->height;

    auto type = image->createType();
    Image newImage (type->create (newFormat, w, h, false));

    if (newFormat == SingleChannel)
    {
        if (! hasAlphaChannel())
        {
            newImage.clear (getBounds(), Colours::black);
        }
        else
        {
            const BitmapData destData (newImage, 0, 0, w, h, BitmapData::writeOnly);
            const BitmapData srcData (*this, 0, 0, w, h);

            for (int y = 0; y < h; ++y)
            {
                auto src = reinterpret_cast<const PixelARGB*> (srcData.getLinePointer (y));
                auto dst = destData.getLinePointer (y);

                for (int x = 0; x < w; ++x)
                    dst[x] = src[x].getAlpha();
            }
        }
    }
    else if (image->pixelFormat == SingleChannel && newFormat == Image::ARGB)
    {
        const BitmapData destData (newImage, 0, 0, w, h, BitmapData::writeOnly);
        const BitmapData srcData (*this, 0, 0, w, h);

        for (int y = 0; y < h; ++y)
        {
            auto src = reinterpret_cast<const PixelAlpha*> (srcData.getLinePointer (y));
            auto dst = reinterpret_cast<PixelARGB*> (destData.getLinePointer (y));

            for (int x = 0; x < w; ++x)
                dst[x].set (src[x]);
        }
    }
    else
    {
        if (hasAlphaChannel())
            newImage.clear (getBounds());

        Graphics g (newImage);
        g.drawImageAt (*this, 0, 0);
    }

    return newImage;
}

NamedValueSet* Image::getProperties() const
{
    return image == nullptr ? nullptr : &(image->userData);
}

//==============================================================================
Image::BitmapData::BitmapData (Image& im, int x, int y, int w, int h, BitmapData::ReadWriteMode mode)
    : width (w), height (h)
{
    // The BitmapData class must be given a valid image, and a valid rectangle within it!
    jassert (im.image != nullptr);
    jassert (x >= 0 && y >= 0 && w > 0 && h > 0 && x + w <= im.getWidth() && y + h <= im.getHeight());

    im.image->initialiseBitmapData (*this, x, y, mode);
    jassert (data != nullptr && pixelStride > 0 && lineStride != 0);
}

Image::BitmapData::BitmapData (const Image& im, int x, int y, int w, int h)
    : width (w), height (h)
{
    // The BitmapData class must be given a valid image, and a valid rectangle within it!
    jassert (im.image != nullptr);
    jassert (x >= 0 && y >= 0 && w > 0 && h > 0 && x + w <= im.getWidth() && y + h <= im.getHeight());

    im.image->initialiseBitmapData (*this, x, y, readOnly);
    jassert (data != nullptr && pixelStride > 0 && lineStride != 0);
}

Image::BitmapData::BitmapData (const Image& im, BitmapData::ReadWriteMode mode)
    : width (im.getWidth()),
      height (im.getHeight())
{
    // The BitmapData class must be given a valid image!
    jassert (im.image != nullptr);

    im.image->initialiseBitmapData (*this, 0, 0, mode);
    jassert (data != nullptr && pixelStride > 0 && lineStride != 0);
}

Image::BitmapData::~BitmapData()
{
}

Colour Image::BitmapData::getPixelColour (int x, int y) const noexcept
{
    jassert (isPositiveAndBelow (x, width) && isPositiveAndBelow (y, height));

    auto pixel = getPixelPointer (x, y);

    switch (pixelFormat)
    {
        case Image::ARGB:           return Colour ( ((const PixelARGB*)  pixel)->getUnpremultiplied());
        case Image::RGB:            return Colour (*((const PixelRGB*)   pixel));
        case Image::SingleChannel:  return Colour (*((const PixelAlpha*) pixel));
        case Image::UnknownFormat:
        default:                    jassertfalse; break;
    }

    return {};
}

void Image::BitmapData::setPixelColour (int x, int y, Colour colour) const noexcept
{
    jassert (isPositiveAndBelow (x, width) && isPositiveAndBelow (y, height));

    auto pixel = getPixelPointer (x, y);
    auto col = colour.getPixelARGB();

    switch (pixelFormat)
    {
        case Image::ARGB:           ((PixelARGB*)  pixel)->set (col); break;
        case Image::RGB:            ((PixelRGB*)   pixel)->set (col); break;
        case Image::SingleChannel:  ((PixelAlpha*) pixel)->set (col); break;
        case Image::UnknownFormat:
        default:                    jassertfalse; break;
    }
}

//==============================================================================
void Image::clear (const Rectangle<int>& area, Colour colourToClearTo)
{
    if (image != nullptr)
    {
        auto g = image->createLowLevelContext();
        g->setFill (colourToClearTo);
        g->fillRect (area, true);
    }
}

//==============================================================================
Colour Image::getPixelAt (int x, int y) const
{
    if (isPositiveAndBelow (x, getWidth()) && isPositiveAndBelow (y, getHeight()))
    {
        const BitmapData srcData (*this, x, y, 1, 1);
        return srcData.getPixelColour (0, 0);
    }

    return {};
}

void Image::setPixelAt (int x, int y, Colour colour)
{
    if (isPositiveAndBelow (x, getWidth()) && isPositiveAndBelow (y, getHeight()))
    {
        const BitmapData destData (*this, x, y, 1, 1, BitmapData::writeOnly);
        destData.setPixelColour (0, 0, colour);
    }
}

void Image::multiplyAlphaAt (int x, int y, float multiplier)
{
    if (isPositiveAndBelow (x, getWidth()) && isPositiveAndBelow (y, getHeight())
         && hasAlphaChannel())
    {
        const BitmapData destData (*this, x, y, 1, 1, BitmapData::readWrite);

        if (isARGB())
            reinterpret_cast<PixelARGB*> (destData.data)->multiplyAlpha (multiplier);
        else
            *(destData.data) = (uint8) (*(destData.data) * multiplier);
    }
}

template <class PixelType>
struct PixelIterator
{
    template <class PixelOperation>
    static void iterate (const Image::BitmapData& data, const PixelOperation& pixelOp)
    {
        for (int y = 0; y < data.height; ++y)
        {
            auto p = data.getLinePointer (y);

            for (int x = 0; x < data.width; ++x)
            {
                pixelOp (*reinterpret_cast<PixelType*> (p));
                p += data.pixelStride;
            }
        }
    }
};

template <class PixelOperation>
static void performPixelOp (const Image::BitmapData& data, const PixelOperation& pixelOp)
{
    switch (data.pixelFormat)
    {
        case Image::ARGB:           PixelIterator<PixelARGB> ::iterate (data, pixelOp); break;
        case Image::RGB:            PixelIterator<PixelRGB>  ::iterate (data, pixelOp); break;
        case Image::SingleChannel:  PixelIterator<PixelAlpha>::iterate (data, pixelOp); break;
        case Image::UnknownFormat:
        default:                    jassertfalse; break;
    }
}

struct AlphaMultiplyOp
{
    float alpha;

    template <class PixelType>
    void operator() (PixelType& pixel) const
    {
        pixel.multiplyAlpha (alpha);
    }
};

void Image::multiplyAllAlphas (float amountToMultiplyBy)
{
    jassert (hasAlphaChannel());

    const BitmapData destData (*this, 0, 0, getWidth(), getHeight(), BitmapData::readWrite);
    performPixelOp (destData, AlphaMultiplyOp { amountToMultiplyBy });
}

struct DesaturateOp
{
    template <class PixelType>
    void operator() (PixelType& pixel) const
    {
        pixel.desaturate();
    }
};

void Image::desaturate()
{
    if (isARGB() || isRGB())
    {
        const BitmapData destData (*this, 0, 0, getWidth(), getHeight(), BitmapData::readWrite);
        performPixelOp (destData, DesaturateOp());
    }
}

void Image::createSolidAreaMask (RectangleList<int>& result, float alphaThreshold) const
{
    if (hasAlphaChannel())
    {
        auto threshold = (uint8) jlimit (0, 255, roundToInt (alphaThreshold * 255.0f));
        SparseSet<int> pixelsOnRow;

        const BitmapData srcData (*this, 0, 0, getWidth(), getHeight());

        for (int y = 0; y < srcData.height; ++y)
        {
            pixelsOnRow.clear();
            auto lineData = srcData.getLinePointer (y);

            if (isARGB())
            {
                for (int x = 0; x < srcData.width; ++x)
                {
                    if (reinterpret_cast<const PixelARGB*> (lineData)->getAlpha() >= threshold)
                        pixelsOnRow.addRange (Range<int> (x, x + 1));

                    lineData += srcData.pixelStride;
                }
            }
            else
            {
                for (int x = 0; x < srcData.width; ++x)
                {
                    if (*lineData >= threshold)
                        pixelsOnRow.addRange (Range<int> (x, x + 1));

                    lineData += srcData.pixelStride;
                }
            }

            for (int i = 0; i < pixelsOnRow.getNumRanges(); ++i)
            {
                auto range = pixelsOnRow.getRange (i);
                result.add (Rectangle<int> (range.getStart(), y, range.getLength(), 1));
            }

            result.consolidate();
        }
    }
    else
    {
        result.add (0, 0, getWidth(), getHeight());
    }
}

void Image::moveImageSection (int dx, int dy,
                              int sx, int sy,
                              int w, int h)
{
    if (dx < 0)
    {
        w += dx;
        sx -= dx;
        dx = 0;
    }

    if (dy < 0)
    {
        h += dy;
        sy -= dy;
        dy = 0;
    }

    if (sx < 0)
    {
        w += sx;
        dx -= sx;
        sx = 0;
    }

    if (sy < 0)
    {
        h += sy;
        dy -= sy;
        sy = 0;
    }

    const int minX = jmin (dx, sx);
    const int minY = jmin (dy, sy);

    w = jmin (w, getWidth()  - jmax (sx, dx));
    h = jmin (h, getHeight() - jmax (sy, dy));

    if (w > 0 && h > 0)
    {
        auto maxX = jmax (dx, sx) + w;
        auto maxY = jmax (dy, sy) + h;

        const BitmapData destData (*this, minX, minY, maxX - minX, maxY - minY, BitmapData::readWrite);

        auto dst = destData.getPixelPointer (dx - minX, dy - minY);
        auto src = destData.getPixelPointer (sx - minX, sy - minY);

        auto lineSize = (size_t) destData.pixelStride * (size_t) w;

        if (dy > sy)
        {
            while (--h >= 0)
            {
                const int offset = h * destData.lineStride;
                memmove (dst + offset, src + offset, lineSize);
            }
        }
        else if (dst != src)
        {
            while (--h >= 0)
            {
                memmove (dst, src, lineSize);
                dst += destData.lineStride;
                src += destData.lineStride;
            }
        }
    }
}

} // namespace juce