//
//  AnimationCurve.h
//  cocos2d_libs
//
//  Created by 徐俊杰 on 2020/5/15.
//

#ifndef AnimationCurve_h
#define AnimationCurve_h

#include "rparticle/Macros/RParticleMacros.h"

#include "rparticle/Utilities/dynamic_array.h"
//#include "SerializeUtility.h"
#include "rparticle/Math/FloatConversion.h"
//#include "Runtime/Math/Vector3.h"
//#include "Runtime/Math/Quaternion.h"
//#include "Runtime/Modules/ExportModules.h"

//#include "rparticle/Serialize/TransferFunctions/SerializeTransfer.h"
#include "rparticle/Serialize/SerializeUtility.h"

NS_RRP_BEGIN

enum { kDefaultWrapMode = 0, kClamp = 1 << 0, kRepeat = 1 << 1, kPingPong = 1 << 2, kClampForever = 1 << 3 };
#define kCurveTimeEpsilon 0.00001F

/*
 AnimationCurves in Maya are represented as time/value keys with 2D tangents which are always of normalized length.
 From the tangents a slope is calculated (tangent.y / tangent.x) -> (thus length of the tangent doesn't matter)
 
 When the slope is multiplied by the time range of the curve (rhs.time - lhs.time) it can be evaluated using
 a standard hermite interpolator.
 
 In the Unity AnimationCurve the slopes are directly stored in the keyframe instead of the 2D tangent vectors.
 */

///@TODO: Curve templates suck.
///       Lets make some implementation where they share the same data structure and only Evaluate is specialized.

template<class T>
struct KeyframeTpl
{
    // DECLARE_SERIALIZE_OPTIMIZE_TRANSFER (Keyframe)
    inline static const char* GetTypeString ()    { return "Keyframe"; }
    inline static bool IsAnimationChannel ()    { return false; }
    inline static bool MightContainPPtr ()    { return false; }
    // Disable transfer optimization in Editor because tangentMode optimized serialization when reading AssetBundles will corrupt data
    inline static bool AllowTransferOptimization ()
    {
#if UNITY_EDITOR
        return false;
#else
        return true;
#endif
    }
    template<class TransferFunction>
    void Transfer (TransferFunction& transfer);
    
    float time;
    T value;
    T inSlope;
    T outSlope;
//#if UNITY_EDITOR
    int tangentMode = 0;
//#endif
    
#if UNITY_EDITOR
    KeyframeTpl ()
    {
        tangentMode = 0;
    }
#else
    KeyframeTpl () {}
#endif
    KeyframeTpl (float t, const T& v);
    
    
    friend bool operator < (const KeyframeTpl& lhs, const KeyframeTpl& rhs) { return lhs.time < rhs.time; }
};

enum AnimationCurveType {
    kFloatCurve = 0,
    kVector3Curve = 1,
    kQuaternionCurve = 2
};

template<class T>
class AnimationCurveTpl
{
public:

    //TODO: Serialize
//    DECLARE_SERIALIZE_NO_PPTR (AnimationCurve)
    template<class TransferFunction>
    void Transfer (TransferFunction& transfer);

    /// Stores the curve as a pure cubic function with 4 coefficients
    struct Cache
    {
        int index;
        float time;
        float timeEnd;
        T coeff[4];
        
        Cache () { time = std::numeric_limits<float>::infinity (); index=0; timeEnd = 0.0f; memset(&coeff, 0, sizeof(coeff)); }
        void Invalidate () { time = std::numeric_limits<float>::infinity (); index=0; }
    };
    
    typedef KeyframeTpl<T> Keyframe;
    
    typedef dynamic_array<Keyframe> KeyframeContainer;
    typedef typename KeyframeContainer::iterator iterator;
    typedef typename KeyframeContainer::const_iterator const_iterator;
    
public:
    AnimationCurveTpl ()
    {
        m_PreInfinity = m_PostInfinity = kInternalClamp;
    }
    
    /// Evaluates the AnimationCurve caching the segment.
    T Evaluate (float curveT) const;
    T EvaluateClamp (float curveT) const;
    
    bool IsValid () const { return m_Curve.size () >= 2; }
    
    int AddKey (const Keyframe& key);
    
    /// Performs no error checking. And doesn't invalidate the cache!
    void AddKeyBackFast (const Keyframe& key) { m_Curve.push_back (key); }
    
    const Keyframe& GetKey (int index) const { AssertMsg(index >= 0 && index < m_Curve.size(), "Index (%d) is out of range [0, %i)", index, (int)m_Curve.size()); return m_Curve[index]; }
    
    /// When changing the keyframe using GetKey you are not allowed to change the time!
    /// After modifying a key you have to call InvalidateCache
    Keyframe& GetKey (int index) { AssertMsg(index >= 0 && index < m_Curve.size(), "Index (%d) is out of range [0, %i)", index, (int)m_Curve.size()); return const_cast<Keyframe&> (m_Curve[index]); }
    
    iterator begin () { return m_Curve.begin (); }
    iterator end () { return m_Curve.end (); }
    const_iterator begin () const { return m_Curve.begin (); }
    const_iterator end () const { return m_Curve.end (); }
    
    void InvalidateCache ();
    
    int GetKeyCount () const { return m_Curve.size (); }
    
    void RemoveKeys (iterator begin, iterator end);
    
    /// Returns the first and last keyframe time
    std::pair<float, float> GetRange () const;
    
    enum { kInternalPingPong = 0, kInternalRepeat = 1, kInternalClamp = 2 };
    
    // How does the curve before the first keyframe
    void SetPreInfinity (int pre);
    int GetPreInfinity () const;
    // How does the curve behave after the last keyframe
    void SetPostInfinity (int post);
    int GetPostInfinity () const;
    
    // How does the curve before the first keyframe
    void SetPreInfinityInternal (int pre) { m_PreInfinity = pre; InvalidateCache (); }
    int GetPreInfinityInternal () const { return m_PreInfinity; }
    // How does the curve behave after the last keyframe
    void SetPostInfinityInternal (int post) { m_PostInfinity = post; InvalidateCache (); }
    int GetPostInfinityInternal () const { return m_PostInfinity; }
    
    void Assign (const Keyframe* begin, const Keyframe* end) { m_Curve.assign (begin, end); InvalidateCache(); }
    void Swap (KeyframeContainer& newArray) { m_Curve.swap(newArray); InvalidateCache(); }
    void Sort () { std::sort(m_Curve.begin(), m_Curve.end()); InvalidateCache(); }
    
    void ResizeUninitialized (int size) { m_Curve.resize_uninitialized(size); }
    
    ///@TODO: Cleanup old code to completely get rid of this
    int FindIndex (const Cache& cache, float curveT) const;
    
    ///@TODO: Cleanup old code to completely get rid of this
    /// Returns the closest keyframe index that is less than time.
    /// Returns -1 if time is outside the range of the curve
    int FindIndex (float time) const;
    
    void CalculateCacheData (Cache& cache, int lhs, int rhs, float timeOffset) const;
    
private:
    
    void FindIndexForSampling (const Cache& cache, float curveT, int& lhs, int& rhs) const;
    
    /// Evaluates the AnimationCurve directly.
    void EvaluateWithoutCache (float curveT, T& output)const;
    
    float WrapTime (float curveT) const;
    
    mutable Cache m_Cache;
    mutable Cache m_ClampCache;
    
    KeyframeContainer m_Curve;
    int   m_PreInfinity;
    int   m_PostInfinity;
};

typedef AnimationCurveTpl<float> AnimationCurveBase;
typedef AnimationCurveTpl<float>      AnimationCurve;
typedef AnimationCurveTpl<Quaternionf> AnimationCurveQuat;
typedef AnimationCurveTpl<Vector3f>   AnimationCurveVec3;

template<class T>
template<class TransferFunction>
inline void KeyframeTpl<T>::Transfer (TransferFunction& transfer)
{
    TRANSFER (time);
    TRANSFER (value);
    TRANSFER (inSlope);
    TRANSFER (outSlope);
#if UNITY_EDITOR
    if (!transfer.IsSerializingForGameRelease())
        TRANSFER (tangentMode);
#endif
}

template<class T>
template<class TransferFunction>
inline void AnimationCurveTpl<T>::Transfer (TransferFunction& transfer)
{
    transfer.SetVersion(2);
    
    //TODO: Transfer dynamic_array
    transfer.Transfer (m_Curve, "m_Curve");//, kHideInEditorMask);
    transfer.Transfer (m_PreInfinity, "m_PreInfinity");//, kHideInEditorMask);
    transfer.Transfer (m_PostInfinity, "m_PostInfinity");//, kHideInEditorMask);
    
    if (transfer.IsReading ())
        InvalidateCache ();
}

inline int TimeToFrame (float time, float sampleRate)
{
    return RoundfToInt(time * sampleRate);
}

inline float FrameToTime (int frame, float sampleRate)
{
    return (float)frame / sampleRate;
}

inline float FloatFrameToTime (float frame, float sampleRate)
{
    return frame / sampleRate;
}


void HandleSteppedCurve (const KeyframeTpl<float>& lhs, const KeyframeTpl<float>& rhs, float& value);
void HandleSteppedTangent (const KeyframeTpl<float>& lhs, const KeyframeTpl<float>& rhs, float& value);

void HandleSteppedCurve (const KeyframeTpl<Vector3f>& lhs, const KeyframeTpl<Vector3f>& rhs, Vector3f& value);
void HandleSteppedTangent (const KeyframeTpl<Vector3f>& lhs, const KeyframeTpl<Vector3f>& rhs, Vector3f& tangent);

void HandleSteppedCurve (const KeyframeTpl<Quaternionf>& lhs, const KeyframeTpl<Quaternionf>& rhs, Quaternionf& tangent);
void HandleSteppedTangent (const KeyframeTpl<Quaternionf>& lhs, const KeyframeTpl<Quaternionf>& rhs, Quaternionf& tangent);

inline float PingPong (float t, float length)
{
    t = Repeat (t, length * 2.0F);
    t = length - Abs (t - length);
    return t;
}


inline float Repeat (float t, float begin, float end)
{
    return Repeat (t - begin, end - begin) + begin;
}

inline double RepeatD (double t, double begin, double end)
{
    return RepeatD (t - begin, end - begin) + begin;
}

inline float PingPong (float t, float begin, float end)
{
    return PingPong (t - begin, end - begin) + begin;
}

#if (defined(__GNUC__) && (__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)) || defined(__clang__)
// in GCC 4.3 and above the explicit template specialization cannot have a storage class
#define SPEC_STORAGE_CLASS inline
#else
#define SPEC_STORAGE_CLASS static
#endif

#define kMaxTan 5729577.9485111479F

template<class T>
static T MaxTan () { return kMaxTan; }

template<>
SPEC_STORAGE_CLASS Quaternionf MaxTan<Quaternionf> () { return Quaternionf(kMaxTan, kMaxTan, kMaxTan, kMaxTan); }

template<>
SPEC_STORAGE_CLASS Vector3f MaxTan<Vector3f> () { return Vector3f(kMaxTan, kMaxTan, kMaxTan); }

#undef kMaxTan

template<class T>
static T Zero () { return T (); }

template<>
SPEC_STORAGE_CLASS Quaternionf Zero<Quaternionf> () { return Quaternionf(0.0F, 0.0F, 0.0F, 0.0F); }

template<>
SPEC_STORAGE_CLASS Vector3f Zero<Vector3f> () { return Vector3f(0.0F, 0.0F, 0.0F); }

#undef SPEC_STORAGE_CLASS

void ScaleCurveValue (AnimationCurve& curve, float scale);
void OffsetCurveValue (AnimationCurve& curve, float offset);
void ScaleCurveTime (AnimationCurve& curve, float scale);
void OffsetCurveTime (AnimationCurve& curve, float offset);

template<class T>
inline T HermiteInterpolate (float t, T p0, T m0, T m1, T p1)
{
    float t2 = t * t;
    float t3 = t2 * t;
    
    float a = 2.0F * t3 - 3.0F * t2 + 1.0F;
    float b = t3 - 2.0F * t2 + t;
    float c = t3 - t2;
    float d = -2.0F * t3 +  3.0F * t2;
    
    return a * p0 + b * m0 + c * m1 + d * p1;
}

struct KeyframeCompare
{
    template<class T>
    bool operator ()(KeyframeTpl<T> const& k, float t) { return k.time < t; }
    // These are necessary for debug STL (validation of predicates)
    template<class T>
    bool operator ()(KeyframeTpl<T> const& k1, KeyframeTpl<T> const& k2) { return k1.time < k2.time; }
    template<class T>
    bool operator ()(float t, KeyframeTpl<T> const& k) { return !operator() (k, t); }
};

NS_RRP_END

#endif /* AnimationCurve_h */