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

   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
{

namespace
{
    template <typename Type>
    Rectangle<Type> coordsToRectangle (Type x, Type y, Type w, Type h) noexcept
    {
       #if JUCE_DEBUG
        const int maxVal = 0x3fffffff;

        jassert ((int) x >= -maxVal && (int) x <= maxVal
              && (int) y >= -maxVal && (int) y <= maxVal
              && (int) w >= 0 && (int) w <= maxVal
              && (int) h >= 0 && (int) h <= maxVal);
       #endif

        return { x, y, w, h };
    }
}

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

//==============================================================================
Graphics::Graphics (const Image& imageToDrawOnto)
    : contextHolder (imageToDrawOnto.createLowLevelContext()),
      context (*contextHolder)
{
    jassert (imageToDrawOnto.isValid()); // Can't draw into a null image!
}

Graphics::Graphics (LowLevelGraphicsContext& internalContext) noexcept
    : context (internalContext)
{
}

Graphics::~Graphics()
{
}

//==============================================================================
void Graphics::resetToDefaultState()
{
    saveStateIfPending();
    context.setFill (FillType());
    context.setFont (Font());
    context.setInterpolationQuality (Graphics::mediumResamplingQuality);
}

bool Graphics::isVectorDevice() const
{
    return context.isVectorDevice();
}

bool Graphics::reduceClipRegion (Rectangle<int> area)
{
    saveStateIfPending();
    return context.clipToRectangle (area);
}

bool Graphics::reduceClipRegion (int x, int y, int w, int h)
{
    return reduceClipRegion (coordsToRectangle (x, y, w, h));
}

bool Graphics::reduceClipRegion (const RectangleList<int>& clipRegion)
{
    saveStateIfPending();
    return context.clipToRectangleList (clipRegion);
}

bool Graphics::reduceClipRegion (const Path& path, const AffineTransform& transform)
{
    saveStateIfPending();
    context.clipToPath (path, transform);
    return ! context.isClipEmpty();
}

bool Graphics::reduceClipRegion (const Image& image, const AffineTransform& transform)
{
    saveStateIfPending();
    context.clipToImageAlpha (image, transform);
    return ! context.isClipEmpty();
}

void Graphics::excludeClipRegion (Rectangle<int> rectangleToExclude)
{
    saveStateIfPending();
    context.excludeClipRectangle (rectangleToExclude);
}

bool Graphics::isClipEmpty() const
{
    return context.isClipEmpty();
}

Rectangle<int> Graphics::getClipBounds() const
{
    return context.getClipBounds();
}

void Graphics::saveState()
{
    saveStateIfPending();
    saveStatePending = true;
}

void Graphics::restoreState()
{
    if (saveStatePending)
        saveStatePending = false;
    else
        context.restoreState();
}

void Graphics::saveStateIfPending()
{
    if (saveStatePending)
    {
        saveStatePending = false;
        context.saveState();
    }
}

void Graphics::setOrigin (Point<int> newOrigin)
{
    saveStateIfPending();
    context.setOrigin (newOrigin);
}

void Graphics::setOrigin (int x, int y)
{
    setOrigin ({ x, y });
}

void Graphics::addTransform (const AffineTransform& transform)
{
    saveStateIfPending();
    context.addTransform (transform);
}

bool Graphics::clipRegionIntersects (Rectangle<int> area) const
{
    return context.clipRegionIntersects (area);
}

void Graphics::beginTransparencyLayer (float layerOpacity)
{
    saveStateIfPending();
    context.beginTransparencyLayer (layerOpacity);
}

void Graphics::endTransparencyLayer()
{
    context.endTransparencyLayer();
}

//==============================================================================
void Graphics::setColour (Colour newColour)
{
    saveStateIfPending();
    context.setFill (newColour);
}

void Graphics::setOpacity (float newOpacity)
{
    saveStateIfPending();
    context.setOpacity (newOpacity);
}

void Graphics::setGradientFill (const ColourGradient& gradient)
{
    setFillType (gradient);
}

void Graphics::setGradientFill (ColourGradient&& gradient)
{
    setFillType (std::move (gradient));
}

void Graphics::setTiledImageFill (const Image& imageToUse, const int anchorX, const int anchorY, const float opacity)
{
    saveStateIfPending();
    context.setFill (FillType (imageToUse, AffineTransform::translation ((float) anchorX, (float) anchorY)));
    context.setOpacity (opacity);
}

void Graphics::setFillType (const FillType& newFill)
{
    saveStateIfPending();
    context.setFill (newFill);
}

//==============================================================================
void Graphics::setFont (const Font& newFont)
{
    saveStateIfPending();
    context.setFont (newFont);
}

void Graphics::setFont (const float newFontHeight)
{
    setFont (context.getFont().withHeight (newFontHeight));
}

Font Graphics::getCurrentFont() const
{
    return context.getFont();
}

//==============================================================================
void Graphics::drawSingleLineText (const String& text, const int startX, const int baselineY,
                                   Justification justification) const
{
    if (text.isNotEmpty())
    {
        // Don't pass any vertical placement flags to this method - they'll be ignored.
        jassert (justification.getOnlyVerticalFlags() == 0);

        auto flags = justification.getOnlyHorizontalFlags();

        if (flags == Justification::right && startX < context.getClipBounds().getX())
            return;

        if (flags == Justification::left && startX > context.getClipBounds().getRight())
            return;

        GlyphArrangement arr;
        arr.addLineOfText (context.getFont(), text, (float) startX, (float) baselineY);

        if (flags != Justification::left)
        {
            auto w = arr.getBoundingBox (0, -1, true).getWidth();

            if ((flags & (Justification::horizontallyCentred | Justification::horizontallyJustified)) != 0)
                w /= 2.0f;

            arr.draw (*this, AffineTransform::translation (-w, 0));
        }
        else
        {
            arr.draw (*this);
        }
    }
}

void Graphics::drawMultiLineText (const String& text, const int startX,
                                  const int baselineY, const int maximumLineWidth,
                                  Justification justification, const float leading) const
{
    if (text.isNotEmpty()
         && startX < context.getClipBounds().getRight())
    {
        GlyphArrangement arr;
        arr.addJustifiedText (context.getFont(), text,
                              (float) startX, (float) baselineY, (float) maximumLineWidth,
                              justification, leading);
        arr.draw (*this);
    }
}

void Graphics::drawText (const String& text, Rectangle<float> area,
                         Justification justificationType, bool useEllipsesIfTooBig) const
{
    if (text.isNotEmpty() && context.clipRegionIntersects (area.getSmallestIntegerContainer()))
    {
        GlyphArrangement arr;
        arr.addCurtailedLineOfText (context.getFont(), text, 0.0f, 0.0f,
                                    area.getWidth(), useEllipsesIfTooBig);

        arr.justifyGlyphs (0, arr.getNumGlyphs(),
                           area.getX(), area.getY(), area.getWidth(), area.getHeight(),
                           justificationType);
        arr.draw (*this);
    }
}

void Graphics::drawText (const String& text, Rectangle<int> area,
                         Justification justificationType, bool useEllipsesIfTooBig) const
{
    drawText (text, area.toFloat(), justificationType, useEllipsesIfTooBig);
}

void Graphics::drawText (const String& text, int x, int y, int width, int height,
                         Justification justificationType, const bool useEllipsesIfTooBig) const
{
    drawText (text, coordsToRectangle (x, y, width, height), justificationType, useEllipsesIfTooBig);
}

void Graphics::drawFittedText (const String& text, Rectangle<int> area,
                               Justification justification,
                               const int maximumNumberOfLines,
                               const float minimumHorizontalScale) const
{
    if (text.isNotEmpty() && (! area.isEmpty()) && context.clipRegionIntersects (area))
    {
        GlyphArrangement arr;
        arr.addFittedText (context.getFont(), text,
                           (float) area.getX(), (float) area.getY(),
                           (float) area.getWidth(), (float) area.getHeight(),
                           justification,
                           maximumNumberOfLines,
                           minimumHorizontalScale);

        arr.draw (*this);
    }
}

void Graphics::drawFittedText (const String& text, int x, int y, int width, int height,
                               Justification justification,
                               const int maximumNumberOfLines,
                               const float minimumHorizontalScale) const
{
    drawFittedText (text, coordsToRectangle (x, y, width, height),
                    justification, maximumNumberOfLines, minimumHorizontalScale);
}

//==============================================================================
void Graphics::fillRect (Rectangle<int> r) const
{
    context.fillRect (r, false);
}

void Graphics::fillRect (Rectangle<float> r) const
{
    context.fillRect (r);
}

void Graphics::fillRect (int x, int y, int width, int height) const
{
    context.fillRect (coordsToRectangle (x, y, width, height), false);
}

void Graphics::fillRect (float x, float y, float width, float height) const
{
    fillRect (coordsToRectangle (x, y, width, height));
}

void Graphics::fillRectList (const RectangleList<float>& rectangles) const
{
    context.fillRectList (rectangles);
}

void Graphics::fillRectList (const RectangleList<int>& rects) const
{
    for (auto& r : rects)
        context.fillRect (r, false);
}

void Graphics::fillAll() const
{
    fillRect (context.getClipBounds());
}

void Graphics::fillAll (Colour colourToUse) const
{
    if (! colourToUse.isTransparent())
    {
        auto clip = context.getClipBounds();

        context.saveState();
        context.setFill (colourToUse);
        context.fillRect (clip, false);
        context.restoreState();
    }
}


//==============================================================================
void Graphics::fillPath (const Path& path) const
{
    if (! (context.isClipEmpty() || path.isEmpty()))
        context.fillPath (path, AffineTransform());
}

void Graphics::fillPath (const Path& path, const AffineTransform& transform) const
{
    if (! (context.isClipEmpty() || path.isEmpty()))
        context.fillPath (path, transform);
}

void Graphics::strokePath (const Path& path,
                           const PathStrokeType& strokeType,
                           const AffineTransform& transform) const
{
    Path stroke;
    strokeType.createStrokedPath (stroke, path, transform, context.getPhysicalPixelScaleFactor());
    fillPath (stroke);
}

//==============================================================================
void Graphics::drawRect (float x, float y, float width, float height, float lineThickness) const
{
    drawRect (coordsToRectangle (x, y, width, height), lineThickness);
}

void Graphics::drawRect (int x, int y, int width, int height, int lineThickness) const
{
    drawRect (coordsToRectangle (x, y, width, height), lineThickness);
}

void Graphics::drawRect (Rectangle<int> r, int lineThickness) const
{
    drawRect (r.toFloat(), (float) lineThickness);
}

void Graphics::drawRect (Rectangle<float> r, const float lineThickness) const
{
    jassert (r.getWidth() >= 0.0f && r.getHeight() >= 0.0f);

    RectangleList<float> rects;
    rects.addWithoutMerging (r.removeFromTop    (lineThickness));
    rects.addWithoutMerging (r.removeFromBottom (lineThickness));
    rects.addWithoutMerging (r.removeFromLeft   (lineThickness));
    rects.addWithoutMerging (r.removeFromRight  (lineThickness));
    context.fillRectList (rects);
}

//==============================================================================
void Graphics::fillEllipse (Rectangle<float> area) const
{
    Path p;
    p.addEllipse (area);
    fillPath (p);
}

void Graphics::fillEllipse (float x, float y, float w, float h) const
{
    fillEllipse (coordsToRectangle (x, y, w, h));
}

void Graphics::drawEllipse (float x, float y, float width, float height, float lineThickness) const
{
    drawEllipse (coordsToRectangle (x, y, width, height), lineThickness);
}

void Graphics::drawEllipse (Rectangle<float> area, float lineThickness) const
{
    Path p;

    if (area.getWidth() == area.getHeight())
    {
        // For a circle, we can avoid having to generate a stroke
        p.addEllipse (area.expanded (lineThickness * 0.5f));
        p.addEllipse (area.reduced  (lineThickness * 0.5f));
        p.setUsingNonZeroWinding (false);
        fillPath (p);
    }
    else
    {
        p.addEllipse (area);
        strokePath (p, PathStrokeType (lineThickness));
    }
}

void Graphics::fillRoundedRectangle (float x, float y, float width, float height, float cornerSize) const
{
    fillRoundedRectangle (coordsToRectangle (x, y, width, height), cornerSize);
}

void Graphics::fillRoundedRectangle (Rectangle<float> r, const float cornerSize) const
{
    Path p;
    p.addRoundedRectangle (r, cornerSize);
    fillPath (p);
}

void Graphics::drawRoundedRectangle (float x, float y, float width, float height,
                                     float cornerSize, float lineThickness) const
{
    drawRoundedRectangle (coordsToRectangle (x, y, width, height), cornerSize, lineThickness);
}

void Graphics::drawRoundedRectangle (Rectangle<float> r, float cornerSize, float lineThickness) const
{
    Path p;
    p.addRoundedRectangle (r, cornerSize);
    strokePath (p, PathStrokeType (lineThickness));
}

void Graphics::drawArrow (Line<float> line, float lineThickness, float arrowheadWidth, float arrowheadLength) const
{
    Path p;
    p.addArrow (line, lineThickness, arrowheadWidth, arrowheadLength);
    fillPath (p);
}

void Graphics::fillCheckerBoard (Rectangle<float> area, float checkWidth, float checkHeight,
                                 Colour colour1, Colour colour2) const
{
    jassert (checkWidth > 0 && checkHeight > 0); // can't be zero or less!

    if (checkWidth > 0 && checkHeight > 0)
    {
        context.saveState();

        if (colour1 == colour2)
        {
            context.setFill (colour1);
            context.fillRect (area);
        }
        else
        {
            auto clipped = context.getClipBounds().getIntersection (area.getSmallestIntegerContainer());

            if (! clipped.isEmpty())
            {
                const int checkNumX = (int) ((clipped.getX() - area.getX()) / checkWidth);
                const int checkNumY = (int) ((clipped.getY() - area.getY()) / checkHeight);
                const float startX = area.getX() + checkNumX * checkWidth;
                const float startY = area.getY() + checkNumY * checkHeight;
                const float right  = (float) clipped.getRight();
                const float bottom = (float) clipped.getBottom();

                for (int i = 0; i < 2; ++i)
                {
                    int cy = i;
                    RectangleList<float> checks;

                    for (float y = startY; y < bottom; y += checkHeight)
                        for (float x = startX + (cy++ & 1) * checkWidth; x < right; x += checkWidth * 2.0f)
                            checks.addWithoutMerging ({ x, y, checkWidth, checkHeight });

                    checks.clipTo (area);
                    context.setFill (i == ((checkNumX ^ checkNumY) & 1) ? colour1 : colour2);
                    context.fillRectList (checks);
                }
            }
        }

        context.restoreState();
    }
}

//==============================================================================
void Graphics::drawVerticalLine (const int x, float top, float bottom) const
{
    if (top < bottom)
        context.fillRect (Rectangle<float> ((float) x, top, 1.0f, bottom - top));
}

void Graphics::drawHorizontalLine (const int y, float left, float right) const
{
    if (left < right)
        context.fillRect (Rectangle<float> (left, (float) y, right - left, 1.0f));
}

void Graphics::drawLine (Line<float> line) const
{
    context.drawLine (line);
}

void Graphics::drawLine (float x1, float y1, float x2, float y2) const
{
    context.drawLine (Line<float> (x1, y1, x2, y2));
}

void Graphics::drawLine (float x1, float y1, float x2, float y2, float lineThickness) const
{
    drawLine (Line<float> (x1, y1, x2, y2), lineThickness);
}

void Graphics::drawLine (Line<float> line, const float lineThickness) const
{
    Path p;
    p.addLineSegment (line, lineThickness);
    fillPath (p);
}

void Graphics::drawDashedLine (Line<float> line, const float* dashLengths,
                               int numDashLengths, float lineThickness, int n) const
{
    jassert (n >= 0 && n < numDashLengths); // your start index must be valid!

    const Point<double> delta ((line.getEnd() - line.getStart()).toDouble());
    const double totalLen = delta.getDistanceFromOrigin();

    if (totalLen >= 0.1)
    {
        const double onePixAlpha = 1.0 / totalLen;

        for (double alpha = 0.0; alpha < 1.0;)
        {
            jassert (dashLengths[n] > 0); // can't have zero-length dashes!

            const double lastAlpha = alpha;
            alpha += dashLengths [n] * onePixAlpha;
            n = (n + 1) % numDashLengths;

            if ((n & 1) != 0)
            {
                const Line<float> segment (line.getStart() + (delta * lastAlpha).toFloat(),
                                           line.getStart() + (delta * jmin (1.0, alpha)).toFloat());

                if (lineThickness != 1.0f)
                    drawLine (segment, lineThickness);
                else
                    context.drawLine (segment);
            }
        }
    }
}

//==============================================================================
void Graphics::setImageResamplingQuality (const Graphics::ResamplingQuality newQuality)
{
    saveStateIfPending();
    context.setInterpolationQuality (newQuality);
}

//==============================================================================
void Graphics::drawImageAt (const Image& imageToDraw, int x, int y, bool fillAlphaChannel) const
{
    drawImageTransformed (imageToDraw,
                          AffineTransform::translation ((float) x, (float) y),
                          fillAlphaChannel);
}

void Graphics::drawImage (const Image& imageToDraw, Rectangle<float> targetArea,
                          RectanglePlacement placementWithinTarget, bool fillAlphaChannelWithCurrentBrush) const
{
    if (imageToDraw.isValid())
        drawImageTransformed (imageToDraw,
                              placementWithinTarget.getTransformToFit (imageToDraw.getBounds().toFloat(), targetArea),
                              fillAlphaChannelWithCurrentBrush);
}

void Graphics::drawImageWithin (const Image& imageToDraw, int dx, int dy, int dw, int dh,
                                RectanglePlacement placementWithinTarget, bool fillAlphaChannelWithCurrentBrush) const
{
    drawImage (imageToDraw, coordsToRectangle (dx, dy, dw, dh).toFloat(),
               placementWithinTarget, fillAlphaChannelWithCurrentBrush);
}

void Graphics::drawImage (const Image& imageToDraw,
                          int dx, int dy, int dw, int dh,
                          int sx, int sy, int sw, int sh,
                          const bool fillAlphaChannelWithCurrentBrush) const
{
    if (imageToDraw.isValid() && context.clipRegionIntersects (coordsToRectangle (dx, dy, dw, dh)))
        drawImageTransformed (imageToDraw.getClippedImage (coordsToRectangle (sx, sy, sw, sh)),
                              AffineTransform::scale (dw / (float) sw, dh / (float) sh)
                                              .translated ((float) dx, (float) dy),
                              fillAlphaChannelWithCurrentBrush);
}

void Graphics::drawImageTransformed (const Image& imageToDraw,
                                     const AffineTransform& transform,
                                     const bool fillAlphaChannelWithCurrentBrush) const
{
    if (imageToDraw.isValid() && ! context.isClipEmpty())
    {
        if (fillAlphaChannelWithCurrentBrush)
        {
            context.saveState();
            context.clipToImageAlpha (imageToDraw, transform);
            fillAll();
            context.restoreState();
        }
        else
        {
            context.drawImage (imageToDraw, transform);
        }
    }
}

//==============================================================================
Graphics::ScopedSaveState::ScopedSaveState (Graphics& g)  : context (g)
{
    context.saveState();
}

Graphics::ScopedSaveState::~ScopedSaveState()
{
    context.restoreState();
}

} // namespace juce