// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#ifndef QSGCURVEFILLNODE_P_H
#define QSGCURVEFILLNODE_P_H

#include <QtGui/qbrush.h>

#include <QtQuick/qtquickexports.h>
#include <QtQuick/private/qsggradientcache_p.h>
#include <QtQuick/private/qsgtransform_p.h>
#include <QtQuick/qsgnode.h>
#include <QtQuick/qsgtextureprovider.h>

#include "qsgcurveabstractnode_p.h"

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists for the convenience
// of a number of Qt sources files.  This header file may change from
// version to version without notice, or even be removed.
//
// We mean it.
//

QT_BEGIN_NAMESPACE

class QSGTextureProvider;

class Q_QUICK_EXPORT QSGCurveFillNode : public QObject, public QSGCurveAbstractNode
{
    Q_OBJECT
public:
    QSGCurveFillNode();

    void setColor(QColor col) override
    {
        m_color = col;
        markDirty(DirtyMaterial);
    }

    QColor color() const
    {
        return m_color;
    }

    void setFillTextureProvider(QSGTextureProvider *provider)
    {
        if (provider == m_textureProvider)
            return;

        if (m_textureProvider != nullptr) {
            disconnect(m_textureProvider, &QSGTextureProvider::textureChanged,
                       this, &QSGCurveFillNode::handleTextureChanged);
            disconnect(m_textureProvider, &QSGTextureProvider::destroyed,
                       this, &QSGCurveFillNode::handleTextureProviderDestroyed);
        }

        m_textureProvider = provider;
        markDirty(DirtyMaterial);

        if (m_textureProvider != nullptr) {
            connect(m_textureProvider, &QSGTextureProvider::textureChanged,
                    this, &QSGCurveFillNode::handleTextureChanged);
            connect(m_textureProvider, &QSGTextureProvider::destroyed,
                    this, &QSGCurveFillNode::handleTextureProviderDestroyed);
        }
    }


    QSGTextureProvider *fillTextureProvider() const
    {
        return m_textureProvider;
    }

    void setFillGradient(const QSGGradientCache::GradientDesc &fillGradient)
    {
        m_fillGradient = fillGradient;
        markDirty(DirtyMaterial);
    }

    const QSGGradientCache::GradientDesc *fillGradient() const
    {
        return &m_fillGradient;
    }

    void setGradientType(QGradient::Type type)
    {
        m_gradientType = type;
        markDirty(DirtyMaterial);
    }

    QGradient::Type gradientType() const
    {
        return m_gradientType;
    }

    void setFillTransform(const QSGTransform &transform)
    {
        m_fillTransform = transform;
        markDirty(DirtyMaterial);
    }

    const QSGTransform *fillTransform() const
    {
        return &m_fillTransform;
    }

    float debug() const
    {
        return m_debug;
    }

    void setDebug(float newDebug)
    {
        m_debug = newDebug;
    }

    void appendTriangle(const std::array<QVector2D, 3> &v, // triangle vertices
                        const std::array<QVector2D, 3> &n, // vertex normals
                        std::function<QVector3D(QVector2D)> uvForPoint
                        )
    {
        QVector3D uv1 = uvForPoint(v[0]);
        QVector3D uv2 = uvForPoint(v[1]);
        QVector3D uv3 = uvForPoint(v[2]);

        QVector2D duvdx = QVector2D(uvForPoint(v[0] + QVector2D(1, 0))) - QVector2D(uv1);
        QVector2D duvdy = QVector2D(uvForPoint(v[0] + QVector2D(0, 1))) - QVector2D(uv1);

        m_uncookedIndexes.append(m_uncookedVertexes.size());
        m_uncookedVertexes.append( { v[0].x(), v[0].y(),
            uv1.x(), uv1.y(), uv1.z(),
            duvdx.x(), duvdx.y(),
            duvdy.x(), duvdy.y(),
            n[0].x(), n[0].y()
        });

        m_uncookedIndexes.append(m_uncookedVertexes.size());
        m_uncookedVertexes.append( { v[1].x(), v[1].y(),
            uv2.x(), uv2.y(), uv2.z(),
            duvdx.x(), duvdx.y(),
            duvdy.x(), duvdy.y(),
            n[1].x(), n[1].y()
        });

        m_uncookedIndexes.append(m_uncookedVertexes.size());
        m_uncookedVertexes.append( { v[2].x(), v[2].y(),
            uv3.x(), uv3.y(), uv3.z(),
            duvdx.x(), duvdx.y(),
            duvdy.x(), duvdy.y(),
            n[2].x(), n[2].y()
        });
    }

    void appendTriangle(const QVector2D &v1,
                        const QVector2D &v2,
                        const QVector2D &v3,
                        const QVector3D &uv1,
                        const QVector3D &uv2,
                        const QVector3D &uv3,
                        const QVector2D &n1,
                        const QVector2D &n2,
                        const QVector2D &n3,
                        const QVector2D &duvdx,
                        const QVector2D &duvdy)
    {
        m_uncookedIndexes.append(m_uncookedVertexes.size());
        m_uncookedVertexes.append( { v1.x(), v1.y(),
            uv1.x(), uv1.y(), uv1.z(),
            duvdx.x(), duvdx.y(),
            duvdy.x(), duvdy.y(),
            n1.x(), n1.y()
        });

        m_uncookedIndexes.append(m_uncookedVertexes.size());
        m_uncookedVertexes.append( { v2.x(), v2.y(),
            uv2.x(), uv2.y(), uv2.z(),
            duvdx.x(), duvdx.y(),
            duvdy.x(), duvdy.y(),
            n2.x(), n2.y()
        });

        m_uncookedIndexes.append(m_uncookedVertexes.size());
        m_uncookedVertexes.append( { v3.x(), v3.y(),
            uv3.x(), uv3.y(), uv3.z(),
            duvdx.x(), duvdx.y(),
            duvdy.x(), duvdy.y(),
            n3.x(), n3.y()
        });
    }

    void appendTriangle(const QVector2D &v1,
                        const QVector2D &v2,
                        const QVector2D &v3,
                        std::function<QVector3D(QVector2D)> uvForPoint)
    {
        appendTriangle({v1, v2, v3}, {}, uvForPoint);
    }

    QVector<quint32> uncookedIndexes() const
    {
        return m_uncookedIndexes;
    }

    void cookGeometry() override;

    void reserve(qsizetype size)
    {
        m_uncookedIndexes.reserve(size);
        m_uncookedVertexes.reserve(size);
    }

    void preprocess() override
    {
        if (m_textureProvider != nullptr) {
            if (QSGDynamicTexture *texture = qobject_cast<QSGDynamicTexture *>(m_textureProvider->texture()))
                texture->updateTexture();
        }
    }

    QVector2D boundsSize() const
    {
        return m_boundsSize;
    }

    void setBoundsSize(const QVector2D &boundsSize)
    {
        m_boundsSize = boundsSize;
    }

private Q_SLOTS:
    void handleTextureChanged()
    {
        markDirty(DirtyMaterial);
    }

    void handleTextureProviderDestroyed()
    {
        m_textureProvider = nullptr;
        markDirty(DirtyMaterial);
    }

private:
    struct CurveNodeVertex
    {
        float x, y, u, v, w;
        float dudx, dvdx, dudy, dvdy; // Size of pixel in curve space (must be same for all vertices in triangle)
        float nx, ny; // normal vector describing the direction to shift the vertex for AA
    };

    void updateMaterial();
    static const QSGGeometry::AttributeSet &attributes();

    QScopedPointer<QSGMaterial> m_material;

    QVector<CurveNodeVertex> m_uncookedVertexes;
    QVector<quint32> m_uncookedIndexes;

    QSGGradientCache::GradientDesc m_fillGradient;
    QSGTextureProvider *m_textureProvider = nullptr;
    QVector2D m_boundsSize;
    QSGTransform m_fillTransform;
    QColor m_color = Qt::white;
    QGradient::Type m_gradientType = QGradient::NoGradient;
    float m_debug = 0.0f;
};

QT_END_NAMESPACE

#endif // QSGCURVEFILLNODE_P_H