//
//  ParticleSystemCurves.h
//  cocos2d_libs
//
//  Created by 徐俊杰 on 2020/4/24.
//

#ifndef ParticleSystemCurves_h
#define ParticleSystemCurves_h

//#include "cocos2d.h"
#include "rparticle/Macros/RParticleMacros.h"
#include "rparticle/ParticleSystemParticle.h"
#include "rparticle/PolynomialCurve.h"
#include "rparticle/Math/AnimationCurve.h"

NS_RRP_BEGIN

struct MinMaxCurve;

// Some profile numbers from a run with 250,000 particles evaluating 3 velocity properties each on Intel i7-2600 CPU @ 3.4 GHz
// Scalar:                                    4.6  ms
// Optimized curve:                            7.2  ms
// Random between 2 scalars:                9.5  ms
// Random between 2 curves:                    9.5  ms
// Non-optimized curve:                        10.0 ms
// Random between 2 non-optimized curves:    12.0 ms

enum ParticleSystemCurveEvalMode
{
    kEMScalar,
    kEMOptimized,
    kEMOptimizedMinMax,
    kEMSlow,
};

enum MinMaxCurveState
{
    kMMCScalar = 0,
    kMMCCurve = 1,
    kMMCTwoCurves = 2,
    kMMCTwoConstants = 3
};

struct MinMaxOptimizedPolyCurves
{
    void Integrate();
    void DoubleIntegrate();
    Vector2f FindMinMaxIntegrated();
    Vector2f FindMinMaxDoubleIntegrated();
    
    OptimizedPolynomialCurve max;
    OptimizedPolynomialCurve min;
};

inline float EvaluateIntegrated (const MinMaxOptimizedPolyCurves& curves, float t, float factor)
{
    const float v0 = curves.min.EvaluateIntegrated (t);
    const float v1 = curves.max.EvaluateIntegrated (t);
    return Lerp (v0, v1, factor);
}

inline float EvaluateDoubleIntegrated (const MinMaxOptimizedPolyCurves& curves, float t, float factor)
{
    const float v0 = curves.min.EvaluateDoubleIntegrated (t);
    const float v1 = curves.max.EvaluateDoubleIntegrated (t);
    return Lerp (v0, v1, factor);
}

struct MinMaxPolyCurves
{
    void Integrate();
    void DoubleIntegrate();
    Vector2f FindMinMaxIntegrated();
    Vector2f FindMinMaxDoubleIntegrated();
    
    PolynomialCurve max;
    PolynomialCurve min;
};

inline float EvaluateIntegrated (const MinMaxPolyCurves& curves, float t, float factor)
{
    const float v0 = curves.min.EvaluateIntegrated (t);
    const float v1 = curves.max.EvaluateIntegrated (t);
    return Lerp (v0, v1, factor);
}

inline float EvaluateDoubleIntegrated (const MinMaxPolyCurves& curves, float t, float factor)
{
    const float v0 = curves.min.EvaluateDoubleIntegrated (t);
    const float v1 = curves.max.EvaluateDoubleIntegrated (t);
    return Lerp (v0, v1, factor);
}

struct MinMaxAnimationCurves
{
    bool SupportsProcedural ();
    
    AnimationCurve max;
    AnimationCurve min;
};

bool BuildCurves (MinMaxOptimizedPolyCurves& polyCurves, const MinMaxAnimationCurves& editorCurves, float scalar, short minMaxState);
void BuildCurves (MinMaxPolyCurves& polyCurves, const MinMaxAnimationCurves& editorCurves, float scalar, short minMaxState);
bool CurvesSupportProcedural (const MinMaxAnimationCurves& editorCurves, short minMaxState);

struct MinMaxCurve
{
    MinMaxOptimizedPolyCurves polyCurves;
private:
    float scalar;        // Since scalar is baked into the optimized curve we use the setter function to modify it.
    
public:
    short minMaxState;    // see enum MinMaxCurveState
    bool isOptimizedCurve;
    
    MinMaxAnimationCurves editorCurves;
    
    MinMaxCurve ();
    
    inline float GetScalar() const { return scalar; }
    inline void SetScalar(float value) { scalar = value; BuildCurves(polyCurves, editorCurves, scalar, minMaxState); }
    inline void SetScalarNoBuild(float value) { scalar = value; }
    
    bool IsOptimized () const { return isOptimizedCurve; }
    bool UsesMinMax () const { return (minMaxState == kMMCTwoCurves) || (minMaxState == kMMCTwoConstants); }
    void OnSetDataEnd() { isOptimizedCurve = BuildCurves(polyCurves, editorCurves, scalar, minMaxState); }
    
    //TODO: Serialize
    /*
    DEFINE_GET_TYPESTRING (MinMaxCurve)
     */

    template<class TransferFunction>
    void Transfer (TransferFunction& transfer);
    
    Vector2f FindMinMax() const;
    Vector2f FindMinMaxIntegrated() const;
    Vector2f FindMinMaxDoubleIntegrated() const;
};

inline float EvaluateSlow (const MinMaxCurve& curve, float t, float factor)
{
    const float v = curve.editorCurves.max.Evaluate(t) * curve.GetScalar ();
    if (curve.minMaxState == kMMCTwoCurves)
        return Lerp (curve.editorCurves.min.Evaluate(t) * curve.GetScalar (), v, factor);
    else
        return v;
}

template<ParticleSystemCurveEvalMode mode>
inline float Evaluate (const MinMaxCurve& curve, float t, float factor = 1.0F)
{
    if(mode == kEMScalar)
    {
        return curve.GetScalar();
    }
    if(mode == kEMOptimized)
    {
        DebugAssert(curve.isOptimizedCurve);
        return curve.polyCurves.max.Evaluate (t);
    }
    else if (mode == kEMOptimizedMinMax)
    {
        DebugAssert(curve.isOptimizedCurve);
        const float v0 = curve.polyCurves.min.Evaluate (t);
        const float v1 = curve.polyCurves.max.Evaluate (t);
        return Lerp (v0, v1, factor);
    }
    else if (mode == kEMSlow)
    {
        return EvaluateSlow (curve, t, factor);
    }
}

inline float Evaluate (const MinMaxCurve& curve, float t, float randomValue = 1.0F)
{
    if (curve.minMaxState == kMMCScalar)
        return curve.GetScalar ();
    
    if (curve.minMaxState == kMMCTwoConstants)
        return Lerp ( curve.editorCurves.min.GetKey(0).value * curve.GetScalar (),
                     curve.editorCurves.max.GetKey(0).value * curve.GetScalar (), randomValue);
    
    DebugAssert(t <= 1.0F && t >= 0.0F);
    if (curve.isOptimizedCurve)
        return Evaluate<kEMOptimizedMinMax> (curve, t, randomValue);
    else
        return Evaluate<kEMSlow> (curve, t, randomValue);
}

struct DualMinMax3DPolyCurves
{
    MinMaxOptimizedPolyCurves optX;
    MinMaxOptimizedPolyCurves optY;
    MinMaxOptimizedPolyCurves optZ;
    MinMaxPolyCurves x;
    MinMaxPolyCurves y;
    MinMaxPolyCurves z;
};

NS_RRP_END

#endif /* ParticleSystemCurves_h */