#define PJ_LIB__

#include <errno.h>
#include <math.h>

#include "proj.h"
#include "proj_internal.h"

PROJ_HEAD(kav5,    "Kavrayskiy V")        "\n\tPCyl, Sph";
PROJ_HEAD(qua_aut, "Quartic Authalic")    "\n\tPCyl, Sph";
PROJ_HEAD(fouc,    "Foucaut")             "\n\tPCyl, Sph";
PROJ_HEAD(mbt_s,   "McBryde-Thomas Flat-Polar Sine (No. 1)") "\n\tPCyl, Sph";


namespace { // anonymous namespace
struct pj_opaque {
	double C_x, C_y, C_p;
	int tan_mode;
};
} // anonymous namespace


static PJ_XY sts_s_forward (PJ_LP lp, PJ *P) {           /* Spheroidal, forward */
    PJ_XY xy = {0.0,0.0};
    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);

    xy.x = Q->C_x * lp.lam * cos(lp.phi);
    xy.y = Q->C_y;
    lp.phi *= Q->C_p;
    const double c = cos(lp.phi);
    if (Q->tan_mode) {
            xy.x *= c * c;
            xy.y *= tan (lp.phi);
    } else {
            xy.x /= c;
            xy.y *= sin (lp.phi);
    }
    return xy;
}


static PJ_LP sts_s_inverse (PJ_XY xy, PJ *P) {           /* Spheroidal, inverse */
    PJ_LP lp = {0.0,0.0};
    struct pj_opaque *Q = static_cast<struct pj_opaque*>(P->opaque);

    xy.y /= Q->C_y;
    lp.phi = Q->tan_mode ? atan (xy.y) : aasin (P->ctx, xy.y);
    const double c = cos (lp.phi);
    lp.phi /= Q->C_p;
    lp.lam = xy.x / (Q->C_x * cos(lp.phi));
    if (Q->tan_mode)
            lp.lam /= c * c;
    else
            lp.lam *= c;
    return lp;
}


static PJ *setup(PJ *P, double p, double q, int mode) {
    P->es  = 0.;
    P->inv = sts_s_inverse;
    P->fwd = sts_s_forward;
    static_cast<struct pj_opaque*>(P->opaque)->C_x = q / p;
    static_cast<struct pj_opaque*>(P->opaque)->C_y = p;
    static_cast<struct pj_opaque*>(P->opaque)->C_p = 1/ q;
    static_cast<struct pj_opaque*>(P->opaque)->tan_mode = mode;
    return P;
}



PJ *PROJECTION(fouc) {
    struct pj_opaque *Q = static_cast<struct pj_opaque*>(calloc (1, sizeof (struct pj_opaque)));
    if (nullptr==Q)
        return pj_default_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/);
    P->opaque = Q;
    return setup(P, 2., 2., 1);
}



PJ *PROJECTION(kav5) {
    struct pj_opaque *Q = static_cast<struct pj_opaque*>(calloc (1, sizeof (struct pj_opaque)));
    if (nullptr==Q)
        return pj_default_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/);
    P->opaque = Q;

    return setup(P, 1.50488, 1.35439, 0);
}



PJ *PROJECTION(qua_aut) {
    struct pj_opaque *Q = static_cast<struct pj_opaque*>(calloc (1, sizeof (struct pj_opaque)));
    if (nullptr==Q)
        return pj_default_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/);
    P->opaque = Q;
    return setup(P, 2., 2., 0);
}



PJ *PROJECTION(mbt_s) {
    struct pj_opaque *Q = static_cast<struct pj_opaque*>(calloc (1, sizeof (struct pj_opaque)));
    if (nullptr==Q)
        return pj_default_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/);
    P->opaque = Q;
    return setup(P, 1.48875, 1.36509, 0);
}
