/********************************************************************
* Description: kinematics for WWU scissor-lift Y-Z manipulator
* Adapted from corexykins.c
*
* Ralph Stirling and Robert Miller 2017-05-05
********************************************************************/

#include "motion.h"
#include "hal.h"
#include "rtapi.h"
#include "rtapi.h"
#include "rtapi_app.h"
#include "rtapi_math.h"
#include "rtapi_string.h"

#define L 60.0		// length of arm

static struct data {
    hal_s32_t joints[EMCMOT_MAX_JOINTS];
} *data;

int kinematicsForward(const double *joints
                     ,EmcPose *pos
                     ,const KINEMATICS_FORWARD_FLAGS *fflags
                     ,KINEMATICS_INVERSE_FLAGS *iflags
                     )
{
//    pos->tran.x = 0.5 * (joints[0] + joints[1]);
//    pos->tran.y = 0.5 * (joints[0] - joints[1]);
//    pos->tran.z = joints[2];
    pos->tran.x = joints[0];
    pos->tran.y = (joints[1] + joints[2])/2;
    pos->tran.z = L * sin(acos((joints[2]-joints[1])/(2*L)));
    pos->a      = joints[3];
    pos->b      = joints[4];
    pos->c      = joints[5];
    pos->u      = joints[6];
    pos->v      = joints[7];
    pos->w      = joints[8];

    return 0;
}

int kinematicsInverse(const EmcPose *pos
                     ,double *joints
                     ,const KINEMATICS_INVERSE_FLAGS *iflags
                     ,KINEMATICS_FORWARD_FLAGS *fflags
                     ) {
//    joints[0] = pos->tran.x + pos->tran.y;
//    joints[1] = pos->tran.x - pos->tran.y;
//    joints[2] = pos->tran.z;
    joints[0] = pos->tran.x;
    joints[1] = pos->tran.y - L * cos(asin(pos->tran.z / L));
    joints[2] = pos->tran.y + L * cos(asin(pos->tran.z / L));
    joints[3] = pos->a;
    joints[4] = pos->b;
    joints[5] = pos->c;
    joints[6] = pos->u;
    joints[7] = pos->v;
    joints[8] = pos->w;

    return 0;
}

int kinematicsHome(EmcPose *world
                  ,double *joint
                  ,KINEMATICS_FORWARD_FLAGS *fflags
                  ,KINEMATICS_INVERSE_FLAGS *iflags
                  ) {
    *fflags = 0;
    *iflags = 0;
    return kinematicsForward(joint, world, fflags, iflags);
}

KINEMATICS_TYPE kinematicsType() { return KINEMATICS_BOTH; }

EXPORT_SYMBOL(kinematicsType);
EXPORT_SYMBOL(kinematicsForward);
EXPORT_SYMBOL(kinematicsInverse);
MODULE_LICENSE("GPL");

static int comp_id;
int rtapi_app_main(void) {
    comp_id = hal_init("scissorkins");
    if(comp_id < 0) return comp_id;

    data = hal_malloc(sizeof(struct data));

    hal_ready(comp_id);
    return 0;
}

void rtapi_app_exit(void) { hal_exit(comp_id); }