/*
Open Asset Import Library (assimp)
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*/

/** @file  LWOAnimation.h
 *  @brief LWOAnimationResolver utility class
 *
 *  This is for all lightwave-related file format, not only LWO.
 *  LWS isthe main purpose.
*/
#ifndef AI_LWO_ANIMATION_INCLUDED
#define AI_LWO_ANIMATION_INCLUDED

//
#include <vector>
#include <list>

struct aiNodeAnim;
struct aiVectorKey;

namespace Assimp {
namespace LWO {

// ---------------------------------------------------------------------------
/** \brief List of recognized LWO envelopes
 */
enum EnvelopeType
{
    EnvelopeType_Position_X = 0x1,
    EnvelopeType_Position_Y = 0x2,
    EnvelopeType_Position_Z = 0x3,

    EnvelopeType_Rotation_Heading = 0x4,
    EnvelopeType_Rotation_Pitch = 0x5,
    EnvelopeType_Rotation_Bank = 0x6,

    EnvelopeType_Scaling_X = 0x7,
    EnvelopeType_Scaling_Y = 0x8,
    EnvelopeType_Scaling_Z = 0x9,

    // -- currently not yet handled
    EnvelopeType_Color_R = 0xa,
    EnvelopeType_Color_G = 0xb,
    EnvelopeType_Color_B = 0xc,

    EnvelopeType_Falloff_X = 0xd,
    EnvelopeType_Falloff_Y = 0xe,
    EnvelopeType_Falloff_Z = 0xf,

    EnvelopeType_Unknown
};

// ---------------------------------------------------------------------------
/** \brief List of recognized LWO interpolation modes
 */
enum InterpolationType
{
    IT_STEP, IT_LINE, IT_TCB, IT_HERM, IT_BEZI, IT_BEZ2
};


// ---------------------------------------------------------------------------
/** \brief List of recognized LWO pre or post range behaviours
 */
enum PrePostBehaviour
{
    PrePostBehaviour_Reset        = 0x0,
    PrePostBehaviour_Constant     = 0x1,
    PrePostBehaviour_Repeat       = 0x2,
    PrePostBehaviour_Oscillate    = 0x3,
    PrePostBehaviour_OffsetRepeat = 0x4,
    PrePostBehaviour_Linear       = 0x5
};

// ---------------------------------------------------------------------------
/** \brief Data structure for a LWO animation keyframe
 */
struct Key {
    Key() AI_NO_EXCEPT 
    : time()
    , value()
    , inter(IT_LINE)
    , params() {
        // empty
    }

    //! Current time
    double time;

    //! Current value
    float value;

    //! How to interpolate this key with previous key?
    InterpolationType inter;

    //! Interpolation parameters
    float params[5];


    // for std::find()
    operator double () {
        return time;
    }
};

// ---------------------------------------------------------------------------
/** \brief Data structure for a LWO animation envelope
 */
struct Envelope {
    Envelope() AI_NO_EXCEPT
    : index()
    , type(EnvelopeType_Unknown)
    , pre(PrePostBehaviour_Constant)
    , post(PrePostBehaviour_Constant)
    , old_first(0)
    , old_last(0) {
        // empty
    }

    //! Index of this envelope
    unsigned int index;

    //! Type of envelope
    EnvelopeType type;

    //! Pre- and post-behavior
    PrePostBehaviour pre,post;

    //! Keyframes for this envelope
    std::vector<Key> keys;

    // temporary data for AnimResolver
    size_t old_first,old_last;
};

// ---------------------------------------------------------------------------
//! @def AI_LWO_ANIM_FLAG_SAMPLE_ANIMS
//! Flag for AnimResolver, subsamples the input data with the rate specified
//! by AnimResolver::SetSampleRate().
#define AI_LWO_ANIM_FLAG_SAMPLE_ANIMS 0x1


// ---------------------------------------------------------------------------
//! @def AI_LWO_ANIM_FLAG_START_AT_ZERO
//! Flag for AnimResolver, ensures that the animations starts at zero.
#define AI_LWO_ANIM_FLAG_START_AT_ZERO 0x2

// ---------------------------------------------------------------------------
/** @brief Utility class to build Assimp animations from LWO envelopes.
 *
 *  Used for both LWO and LWS (MOT also).
 */
class AnimResolver
{
public:

    // ------------------------------------------------------------------
    /** @brief Construct an AnimResolver from a given list of envelopes
     *  @param envelopes Input envelopes. May be empty.
     *  @param Output tick rate, per second
     *  @note The input envelopes are possibly modified.
     */
    AnimResolver(std::list<Envelope>& envelopes, double tick);

public:

    // ------------------------------------------------------------------
    /** @brief Extract the bind-pose transformation matrix.
     *  @param out Receives bind-pose transformation matrix
     */
    void ExtractBindPose(aiMatrix4x4& out);

    // ------------------------------------------------------------------
    /** @brief Extract a node animation channel
     *  @param out Receives a pointer to a newly allocated node anim.
     *    If there's just one keyframe defined, *out is set to nullptr and
     *    no animation channel is computed.
     *  @param flags Any combination of the AI_LWO_ANIM_FLAG_XXX flags.
     */
    void ExtractAnimChannel(aiNodeAnim** out, unsigned int flags = 0);


    // ------------------------------------------------------------------
    /** @brief Set the sampling rate for ExtractAnimChannel().
     *
     *  Non-linear interpolations are subsampled with this rate (keys
     *  per second). Closer sampling positions, if existent, are kept.
     *  The sampling rate defaults to 0, if this value is not changed and
     *  AI_LWO_ANIM_FLAG_SAMPLE_ANIMS is specified for ExtractAnimChannel(),
     *  the class finds a suitable sample rate by itself.
     */
    void SetSampleRate(double sr) {
        sample_rate = sr;
    }

    // ------------------------------------------------------------------
    /** @brief Getter for SetSampleRate()
     */
    double GetSampleRate() const {
        return sample_rate;
    }

    // ------------------------------------------------------------------
    /** @brief Set the animation time range
     *
     *  @param first Time where the animation starts, in ticks
     *  @param last  Time where the animation ends, in ticks
     */
    void SetAnimationRange(double _first, double _last) {
        first = _first;
        last  = _last;

        ClearAnimRangeSetup();
        UpdateAnimRangeSetup();
    }

protected:

    // ------------------------------------------------------------------
    /** @brief Build linearly subsampled keys from 3 single envelopes
     *  @param out Receives output keys
     *  @param envl_x X-component envelope
     *  @param envl_y Y-component envelope
     *  @param envl_z Z-component envelope
     *  @param flags Any combination of the AI_LWO_ANIM_FLAG_XXX flags.
     *  @note Up to two input envelopes may be nullptr
     */
    void GetKeys(std::vector<aiVectorKey>& out,
        LWO::Envelope* envl_x,
        LWO::Envelope* envl_y,
        LWO::Envelope* envl_z,
        unsigned int flags);

    // ------------------------------------------------------------------
    /** @brief Resolve a single animation key by applying the right
     *  interpolation to it.
     *  @param cur Current key
     *  @param envl Envelope working on
     *  @param time time to be interpolated
     *  @param fill Receives the interpolated output value.
     */
    void DoInterpolation(std::vector<LWO::Key>::const_iterator cur,
        LWO::Envelope* envl,double time, float& fill);

    // ------------------------------------------------------------------
    /** @brief Almost the same, except we won't handle pre/post
     *  conditions here.
     *  @see DoInterpolation
     */
    void DoInterpolation2(std::vector<LWO::Key>::const_iterator beg,
        std::vector<LWO::Key>::const_iterator end,double time, float& fill);

    // ------------------------------------------------------------------
    /** @brief Interpolate 2 tracks if one is given
     *
     *  @param out Receives extra output keys
     *  @param key_out Primary output key
     *  @param time Time to interpolate for
     */
    void InterpolateTrack(std::vector<aiVectorKey>& out,
        aiVectorKey& key_out,double time);

    // ------------------------------------------------------------------
    /** @brief Subsample an animation track by a given sampling rate
     *
     *  @param out Receives output keys. Last key at input defines the
     *    time where subsampling starts.
     *  @param time Time to end subsampling at
     *  @param sample_delta Time delta between two samples
     */
    void SubsampleAnimTrack(std::vector<aiVectorKey>& out,
        double time,double sample_delta);

    // ------------------------------------------------------------------
    /** @brief Delete all keys which we inserted to match anim setup
     */
    void ClearAnimRangeSetup();

    // ------------------------------------------------------------------
    /** @brief Insert extra keys to match LWO's pre and post behaviours
     *  in a given time range [first...last]
     */
    void UpdateAnimRangeSetup();

private:
    std::list<Envelope>& envelopes;
    double sample_rate;

    LWO::Envelope* trans_x, *trans_y, *trans_z;
    LWO::Envelope* rotat_x, *rotat_y, *rotat_z;
    LWO::Envelope* scale_x, *scale_y, *scale_z;

    double first, last;
    bool need_to_setup;

    // temporary storage
    LWO::Envelope* envl_x, * envl_y, * envl_z;
    std::vector<LWO::Key>::const_iterator cur_x,cur_y,cur_z;
    bool end_x, end_y, end_z;

    unsigned int flags;
    double sample_delta;
};

} // end namespace LWO
} // end namespace Assimp

#endif // !! AI_LWO_ANIMATION_INCLUDED
