/*
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Open Asset Import Library (assimp)
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*/

/** @file anim.h
 *  @brief Defines the data structures in which the imported animations
 *  are returned.
 */
#pragma once
#ifndef AI_ANIM_H_INC
#define AI_ANIM_H_INC

#include "types.h"
#include "quaternion.h"

#ifdef __cplusplus
extern "C" {
#endif

// ---------------------------------------------------------------------------
/** A time-value pair specifying a certain 3D vector for the given time. */
struct aiVectorKey
{
    /** The time of this key */
    float mTime;

    /** The value of this key */
    C_STRUCT aiVector3D mValue;

#ifdef __cplusplus

    //! Default constructor
    aiVectorKey(){}

    //! Construction from a given time and key value
    aiVectorKey(float time, const aiVector3D& value)
        :   mTime   (time)
        ,   mValue  (value)
    {}


    typedef aiVector3D elem_type;

    // Comparison operators. For use with std::find();
    bool operator == (const aiVectorKey& o) const {
        return o.mValue == this->mValue;
    }
    bool operator != (const aiVectorKey& o) const {
        return o.mValue != this->mValue;
    }

    // Relational operators. For use with std::sort();
    bool operator < (const aiVectorKey& o) const {
        return mTime < o.mTime;
    }
    bool operator > (const aiVectorKey& o) const {
        return mTime > o.mTime;
    }
#endif
};

// ---------------------------------------------------------------------------
/** A time-value pair specifying a rotation for the given time.
 *  Rotations are expressed with quaternions. */
struct aiQuatKey
{
    /** The time of this key */
    float mTime;

    /** The value of this key */
    C_STRUCT aiQuaternion mValue;

#ifdef __cplusplus
    aiQuatKey(){
    }

    /** Construction from a given time and key value */
    aiQuatKey(float time, const aiQuaternion& value)
        :   mTime   (time)
        ,   mValue  (value)
    {}

    typedef aiQuaternion elem_type;

    // Comparison operators. For use with std::find();
    bool operator == (const aiQuatKey& o) const {
        return o.mValue == this->mValue;
    }
    bool operator != (const aiQuatKey& o) const {
        return o.mValue != this->mValue;
    }

    // Relational operators. For use with std::sort();
    bool operator < (const aiQuatKey& o) const {
        return mTime < o.mTime;
    }
    bool operator > (const aiQuatKey& o) const {
        return mTime > o.mTime;
    }
#endif
};

// ---------------------------------------------------------------------------
/** Binds a anim mesh to a specific point in time. */
struct aiMeshKey
{
    /** The time of this key */
    float mTime;

    /** Index into the aiMesh::mAnimMeshes array of the
     *  mesh coresponding to the #aiMeshAnim hosting this
     *  key frame. The referenced anim mesh is evaluated
     *  according to the rules defined in the docs for #aiAnimMesh.*/
    unsigned int mValue;

#ifdef __cplusplus

    aiMeshKey() {
    }

    /** Construction from a given time and key value */
    aiMeshKey(float time, const unsigned int value)
        :   mTime   (time)
        ,   mValue  (value)
    {}

    typedef unsigned int elem_type;

    // Comparison operators. For use with std::find();
    bool operator == (const aiMeshKey& o) const {
        return o.mValue == this->mValue;
    }
    bool operator != (const aiMeshKey& o) const {
        return o.mValue != this->mValue;
    }

    // Relational operators. For use with std::sort();
    bool operator < (const aiMeshKey& o) const {
        return mTime < o.mTime;
    }
    bool operator > (const aiMeshKey& o) const {
        return mTime > o.mTime;
    }

#endif
};

// ---------------------------------------------------------------------------
/** Defines how an animation channel behaves outside the defined time
 *  range. This corresponds to aiNodeAnim::mPreState and
 *  aiNodeAnim::mPostState.*/
enum aiAnimBehaviour
{
    /** The value from the default node transformation is taken*/
    aiAnimBehaviour_DEFAULT  = 0x0,

    /** The nearest key value is used without interpolation */
    aiAnimBehaviour_CONSTANT = 0x1,

    /** The value of the nearest two keys is linearly
     *  extrapolated for the current time value.*/
    aiAnimBehaviour_LINEAR   = 0x2,

    /** The animation is repeated.
     *
     *  If the animation key go from n to m and the current
     *  time is t, use the value at (t-n) % (|m-n|).*/
    aiAnimBehaviour_REPEAT   = 0x3,



    /** This value is not used, it is just here to force the
     *  the compiler to map this enum to a 32 Bit integer  */
#ifndef SWIG
    _aiAnimBehaviour_Force32Bit = INT_MAX
#endif
};

// ---------------------------------------------------------------------------
/** Describes the animation of a single node. The name specifies the
 *  bone/node which is affected by this animation channel. The keyframes
 *  are given in three separate series of values, one each for position,
 *  rotation and scaling. The transformation matrix computed from these
 *  values replaces the node's original transformation matrix at a
 *  specific time.
 *  This means all keys are absolute and not relative to the bone default pose.
 *  The order in which the transformations are applied is
 *  - as usual - scaling, rotation, translation.
 *
 *  @note All keys are returned in their correct, chronological order.
 *  Duplicate keys don't pass the validation step. Most likely there
 *  will be no negative time values, but they are not forbidden also ( so
 *  implementations need to cope with them! ) */
struct aiNodeAnim
{
    /** The name of the node affected by this animation. The node
     *  must exist and it must be unique.*/
    C_STRUCT aiString mNodeName;

    /** The number of position keys */
    unsigned int mNumPositionKeys;

    /** The position keys of this animation channel. Positions are
     * specified as 3D vector. The array is mNumPositionKeys in size.
     *
     * If there are position keys, there will also be at least one
     * scaling and one rotation key.*/
    C_STRUCT aiVectorKey* mPositionKeys;

    /** The number of rotation keys */
    unsigned int mNumRotationKeys;

    /** The rotation keys of this animation channel. Rotations are
     *  given as quaternions,  which are 4D vectors. The array is
     *  mNumRotationKeys in size.
     *
     * If there are rotation keys, there will also be at least one
     * scaling and one position key. */
    C_STRUCT aiQuatKey* mRotationKeys;

    /** The number of scaling keys */
    unsigned int mNumScalingKeys;

    /** The scaling keys of this animation channel. Scalings are
     *  specified as 3D vector. The array is mNumScalingKeys in size.
     *
     * If there are scaling keys, there will also be at least one
     * position and one rotation key.*/
    C_STRUCT aiVectorKey* mScalingKeys;

    /** Defines how the animation behaves before the first
     *  key is encountered.
     *
     *  The default value is aiAnimBehaviour_DEFAULT (the original
     *  transformation matrix of the affected node is used).*/
    C_ENUM aiAnimBehaviour mPreState;

    /** Defines how the animation behaves after the last
     *  key was processed.
     *
     *  The default value is aiAnimBehaviour_DEFAULT (the original
     *  transformation matrix of the affected node is taken).*/
    C_ENUM aiAnimBehaviour mPostState;

#ifdef __cplusplus
    aiNodeAnim()
    {
        mNumPositionKeys = 0; mPositionKeys = NULL;
        mNumRotationKeys = 0; mRotationKeys = NULL;
        mNumScalingKeys  = 0; mScalingKeys  = NULL;

        mPreState = mPostState = aiAnimBehaviour_DEFAULT;
    }

    ~aiNodeAnim()
    {
        delete [] mPositionKeys;
        delete [] mRotationKeys;
        delete [] mScalingKeys;
    }
#endif // __cplusplus
};

// ---------------------------------------------------------------------------
/** Describes vertex-based animations for a single mesh or a group of
 *  meshes. Meshes carry the animation data for each frame in their
 *  aiMesh::mAnimMeshes array. The purpose of aiMeshAnim is to
 *  define keyframes linking each mesh attachment to a particular
 *  point in time. */
struct aiMeshAnim
{
    /** Name of the mesh to be animated. An empty string is not allowed,
     *  animated meshes need to be named (not necessarily uniquely,
     *  the name can basically serve as wildcard to select a group
     *  of meshes with similar animation setup)*/
    C_STRUCT aiString mName;

    /** Size of the #mKeys array. Must be 1, at least. */
    unsigned int mNumKeys;

    /** Key frames of the animation. May not be NULL. */
    C_STRUCT aiMeshKey* mKeys;

#ifdef __cplusplus

    aiMeshAnim()
        : mNumKeys()
        , mKeys()
    {}

    ~aiMeshAnim()
    {
        delete[] mKeys;
    }

#endif
};

// ---------------------------------------------------------------------------
/** An animation consists of keyframe data for a number of nodes. For
 *  each node affected by the animation a separate series of data is given.*/
struct aiAnimation
{
    /** The name of the animation. If the modeling package this data was
     *  exported from does support only a single animation channel, this
     *  name is usually empty (length is zero). */
    C_STRUCT aiString mName;

    /** Duration of the animation in ticks.  */
    float mDuration;

    /** Ticks per second. 0 if not specified in the imported file */
    float mTicksPerSecond;

    /** The number of bone animation channels. Each channel affects
     *  a single node. */
    unsigned int mNumChannels;

    /** The node animation channels. Each channel affects a single node.
     *  The array is mNumChannels in size. */
    C_STRUCT aiNodeAnim** mChannels;


    /** The number of mesh animation channels. Each channel affects
     *  a single mesh and defines vertex-based animation. */
    unsigned int mNumMeshChannels;

    /** The mesh animation channels. Each channel affects a single mesh.
     *  The array is mNumMeshChannels in size. */
    C_STRUCT aiMeshAnim** mMeshChannels;

#ifdef __cplusplus
    aiAnimation()
        : mDuration(-1.)
        , mTicksPerSecond()
        , mNumChannels()
        , mChannels()
        , mNumMeshChannels()
        , mMeshChannels()
    {
    }

    ~aiAnimation()
    {
        // DO NOT REMOVE THIS ADDITIONAL CHECK
        if (mNumChannels && mChannels)  {
            for( unsigned int a = 0; a < mNumChannels; a++) {
                delete mChannels[a];
            }

        delete [] mChannels;
        }
        if (mNumMeshChannels && mMeshChannels)  {
            for( unsigned int a = 0; a < mNumMeshChannels; a++) {
                delete mMeshChannels[a];
            }

        delete [] mMeshChannels;
        }
    }
#endif // __cplusplus
};

#ifdef __cplusplus
}


// some C++ utilities for inter- and extrapolation
namespace Assimp {

// ---------------------------------------------------------------------------
/** @brief CPP-API: Utility class to simplify interpolations of various data types.
 *
 *  The type of interpolation is chosen automatically depending on the
 *  types of the arguments. */
template <typename T>
struct Interpolator
{
    // ------------------------------------------------------------------
    /** @brief Get the result of the interpolation between a,b.
     *
     *  The interpolation algorithm depends on the type of the operands.
     *  aiQuaternion's and aiQuatKey's SLERP, the rest does a simple
     *  linear interpolation. */
    void operator () (T& out,const T& a, const T& b, ai_real d) const {
        out = a + (b-a)*d;
    }
}; // ! Interpolator <T>

//! @cond Never

template <>
struct Interpolator <aiQuaternion>  {
    void operator () (aiQuaternion& out,const aiQuaternion& a,
        const aiQuaternion& b, ai_real d) const
    {
        aiQuaternion::Interpolate(out,a,b,d);
    }
}; // ! Interpolator <aiQuaternion>

template <>
struct Interpolator <unsigned int>  {
    void operator () (unsigned int& out,unsigned int a,
        unsigned int b, ai_real d) const
    {
        out = d>0.5f ? b : a;
    }
}; // ! Interpolator <aiQuaternion>

template <>
struct Interpolator  <aiVectorKey>  {
    void operator () (aiVector3D& out,const aiVectorKey& a,
        const aiVectorKey& b, ai_real d) const
    {
        Interpolator<aiVector3D> ipl;
        ipl(out,a.mValue,b.mValue,d);
    }
}; // ! Interpolator <aiVectorKey>

template <>
struct Interpolator <aiQuatKey>     {
    void operator () (aiQuaternion& out, const aiQuatKey& a,
        const aiQuatKey& b, ai_real d) const
    {
        Interpolator<aiQuaternion> ipl;
        ipl(out,a.mValue,b.mValue,d);
    }
}; // ! Interpolator <aiQuatKey>

template <>
struct Interpolator <aiMeshKey>     {
    void operator () (unsigned int& out, const aiMeshKey& a,
        const aiMeshKey& b, ai_real d) const
    {
        Interpolator<unsigned int> ipl;
        ipl(out,a.mValue,b.mValue,d);
    }
}; // ! Interpolator <aiQuatKey>

//! @endcond
} //  ! end namespace Assimp



#endif // __cplusplus
#endif // AI_ANIM_H_INC
