// Copyright (C) 2016 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 FOLLOWEMITTER_H
#define FOLLOWEMITTER_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
#include "qquickparticleemitter_p.h"
#include "qquickparticleaffector_p.h"

QT_BEGIN_NAMESPACE

class Q_QUICKPARTICLES_EXPORT QQuickTrailEmitter : public QQuickParticleEmitter
{
    Q_OBJECT
    Q_PROPERTY(QString follow READ follow WRITE setFollow NOTIFY followChanged)
    Q_PROPERTY(int emitRatePerParticle READ particlesPerParticlePerSecond WRITE setParticlesPerParticlePerSecond NOTIFY particlesPerParticlePerSecondChanged)

    Q_PROPERTY(QQuickParticleExtruder* emitShape READ emissonShape WRITE setEmissionShape NOTIFY emissionShapeChanged)
    Q_PROPERTY(qreal emitHeight READ emitterYVariation WRITE setEmitterYVariation NOTIFY emitterYVariationChanged)
    Q_PROPERTY(qreal emitWidth READ emitterXVariation WRITE setEmitterXVariation NOTIFY emitterXVariationChanged)
    QML_NAMED_ELEMENT(TrailEmitter)
    QML_ADDED_IN_VERSION(2, 0)

public:
    enum EmitSize {
        ParticleSize = -2//Anything less than 0 will do
    };
    Q_ENUM(EmitSize)
    explicit QQuickTrailEmitter(QQuickItem *parent = nullptr);
    void emitWindow(int timeStamp) override;
    void reset() override;

    int particlesPerParticlePerSecond() const
    {
        return m_particlesPerParticlePerSecond;
    }

    qreal emitterXVariation() const
    {
        return m_emitterXVariation;
    }

    qreal emitterYVariation() const
    {
        return m_emitterYVariation;
    }

    QString follow() const
    {
        return m_follow;
    }

    QQuickParticleExtruder* emissonShape() const
    {
        return m_emissionExtruder;
    }

Q_SIGNALS:
    void emitFollowParticles(
            const QList<QQuickV4ParticleData> &particles,
            const QQuickV4ParticleData &followed);

    void particlesPerParticlePerSecondChanged(int arg);

    void emitterXVariationChanged(qreal arg);

    void emitterYVariationChanged(qreal arg);

    void followChanged(const QString &arg);

    void emissionShapeChanged(QQuickParticleExtruder* arg);

public Q_SLOTS:

    void setParticlesPerParticlePerSecond(int arg)
    {
        if (m_particlesPerParticlePerSecond != arg) {
            m_particlesPerParticlePerSecond = arg;
            Q_EMIT particlesPerParticlePerSecondChanged(arg);
        }
    }
    void setEmitterXVariation(qreal arg)
    {
        if (m_emitterXVariation != arg) {
            m_emitterXVariation = arg;
            Q_EMIT emitterXVariationChanged(arg);
        }
    }

    void setEmitterYVariation(qreal arg)
    {
        if (m_emitterYVariation != arg) {
            m_emitterYVariation = arg;
            Q_EMIT emitterYVariationChanged(arg);
        }
    }

    void setFollow(const QString &arg)
    {
        if (m_follow != arg) {
            m_follow = arg;
            Q_EMIT followChanged(arg);
        }
    }

    void setEmissionShape(QQuickParticleExtruder* arg)
    {
        if (m_emissionExtruder != arg) {
            m_emissionExtruder = arg;
            Q_EMIT emissionShapeChanged(arg);
        }
    }

private Q_SLOTS:
    void recalcParticlesPerSecond();

private:
    QVector<qreal> m_lastEmission;
    int m_particlesPerParticlePerSecond;
    qreal m_lastTimeStamp;
    qreal m_emitterXVariation;
    qreal m_emitterYVariation;
    QString m_follow;
    int m_followCount;
    QQuickParticleExtruder* m_emissionExtruder;
    QQuickParticleExtruder* m_defaultEmissionExtruder;
    bool isEmitFollowConnected();
};

QT_END_NAMESPACE
#endif // FOLLOWEMITTER_H