/******************************************************************************
 * QSkinny - Copyright (C) The authors
 *           SPDX-License-Identifier: BSD-3-Clause
 *****************************************************************************/

#include "QskShapeNode.h"
#include "QskGradient.h"
#include "QskGradientDirection.h"
#include "QskVertex.h"
#include "QskFillNodePrivate.h"
#include "QskInternalMacros.h"

QSK_QT_PRIVATE_BEGIN
#include <private/qvectorpath_p.h>
#include <private/qtriangulator_p.h>
QSK_QT_PRIVATE_END

#if 0

// keeping the index list
static void qskUpdateGeometry( const QPainterPath& path,
    const QTransform& transform, const QColor&, QSGGeometry& geometry )
{
    const auto ts = qTriangulate( path, transform, 1, false );

    geometry.allocate( ts.vertices.size(), ts.indices.size() );

    auto vertexData = reinterpret_cast< float* >( geometry.vertexData() );
    const auto points = ts.vertices.constData();

    for ( int i = 0; i < ts.vertices.count(); i++ )
        vertexData[i] = points[i];

    memcpy( geometry.indexData(), ts.indices.data(),
        ts.indices.size() * sizeof( quint16 ) );
}

#else

static void qskUpdateGeometry( const QPainterPath& path,
    const QTransform& transform, const QColor& color, QSGGeometry& geometry )
{
    const auto ts = qTriangulate( path, transform, 1, false );

    /*
        The triangulation of a random path usually does not lead to index lists
        that allow substantially reducing the number of vertices.

        As we have to iterate over the vertex buffer to copy qreal to float
        anyway we reorder according to the index buffer and drop
        the index buffer.

        QTriangleSet:

        vertices: (x[i[n]], y[i[n]]), (x[j[n]], y[j[n]]), (x[k[n]], y[k[n]]), n = 0, 1, ...
        QVector<qreal> vertices; // [x[0], y[0], x[1], y[1], x[2], ...]
        QVector<quint16> indices; // [i[0], j[0], k[0], i[1], j[1], k[1], i[2], ...]
     */

    const auto points = ts.vertices.constData();
    const auto indices = reinterpret_cast< const quint16* >( ts.indices.data() );

    geometry.allocate( ts.indices.size() );

    if ( color.isValid() )
    {
        const QskVertex::Color c = color;

        auto vertexData = geometry.vertexDataAsColoredPoint2D();
        for ( int i = 0; i < ts.indices.size(); i++ )
        {
            const int j = 2 * indices[i];
            vertexData[i].set( points[j], points[j + 1], c.r, c.g, c.b, c.a );
        }
    }
    else
    {
        auto vertexData = geometry.vertexDataAsPoint2D();
        for ( int i = 0; i < ts.indices.size(); i++ )
        {
            const int j = 2 * indices[i];
            vertexData[i].set( points[j], points[j + 1] );
        }
    }
}

#endif

class QskShapeNodePrivate final : public QskFillNodePrivate
{
  public:
    /*
        Is there a better way to find out if the path has changed
        beside storing a copy ( even, when internally with Copy On Write ) ?
     */
    QPainterPath path;
    QTransform transform;
};

QskShapeNode::QskShapeNode()
    : QskFillNode( *new QskShapeNodePrivate )
{
#if 1
    /*
        for some reason we have a broken geometry for some of
        contours of shapes example, when not setting Monochrome.
        Does not make any sense and needs to be understood: TODO
     */
    setColoring( Monochrome );
#endif

    geometry()->setDrawingMode( QSGGeometry::DrawTriangles );
}

QskShapeNode::~QskShapeNode()
{
}

void QskShapeNode::updatePath( const QPainterPath& path,
    const QTransform& transform, const QRectF& rect, const QskGradient& gradient )
{
    Q_D( QskShapeNode );

    if ( path.isEmpty() || !gradient.isVisible() )
    {
        d->path = QPainterPath();
        d->transform = QTransform();
        resetGeometry();

        return;
    }

    QColor c;

    if ( gradient.isMonochrome() && hasHint( PreferColoredGeometry ) )
        c = gradient.startColor();

    const bool isDirty = ( isGeometryColored() != c.isValid() );

    if ( c.isValid() )
        setColoring( QskFillNode::Polychrome );
    else
        setColoring( rect, gradient );

    if ( isDirty || ( transform != d->transform ) || ( path != d->path ) )
    {
        d->path = path;
        d->transform = transform;

        qskUpdateGeometry( path, transform, c, *geometry() );

        geometry()->markVertexDataDirty();
        markDirty( QSGNode::DirtyGeometry );
    }
}