#include <errno.h>

#include <math.h>

#include "proj.h"

#include "proj_internal.h"

namespace { // anonymous namespace

struct pj_eqc_data {

    double rc;

};

} // anonymous namespace

PROJ_HEAD(eqc, "Equidistant Cylindrical (Plate Carree)")

"\n\tCyl, Sph\n\tlat_ts=[, lat_0=0]";

static PJ_XY eqc_s_forward(PJ_LP lp, PJ *P) { /* Spheroidal, forward */

    PJ_XY xy = {0.0, 0.0};

    struct pj_eqc_data *Q = static_cast<struct pj_eqc_data *>(P->opaque);

    xy.x = Q->rc * lp.lam;

    xy.y = lp.phi - P->phi0;

    return xy;

}

static PJ_LP eqc_s_inverse(PJ_XY xy, PJ *P) { /* Spheroidal, inverse */

    PJ_LP lp = {0.0, 0.0};

    struct pj_eqc_data *Q = static_cast<struct pj_eqc_data *>(P->opaque);

    lp.lam = xy.x / Q->rc;

    lp.phi = xy.y + P->phi0;

    return lp;

}

PJ *PJ_PROJECTION(eqc) {

    struct pj_eqc_data *Q = static_cast<struct pj_eqc_data *>(

        calloc(1, sizeof(struct pj_eqc_data)));

    if (nullptr == Q)

        return pj_default_destructor(P, PROJ_ERR_OTHER /*ENOMEM*/);

    P->opaque = Q;

    if ((Q->rc = cos(pj_param(P->ctx, P->params, "rlat_ts").f)) <= 0.) {

        proj_log_error(

            P, _("Invalid value for lat_ts: |lat_ts| should be <= 90°"));

        return pj_default_destructor(P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);

    }

    P->inv = eqc_s_inverse;

    P->fwd = eqc_s_forward;

    P->es = 0.;

    return P;

}