#include "proj.h"

#include "proj_internal.h"

#include <errno.h>

#include <math.h>

PROJ_HEAD(bonne, "Bonne (Werner lat_1=90)")

"\n\tConic Sph&Ell\n\tlat_1=";

#define EPS10 1e-10

namespace { // anonymous namespace

struct pj_bonne_data {

    double phi1;

    double cphi1;

    double am1;

    double m1;

    double *en;

};

} // anonymous namespace

static PJ_XY bonne_e_forward(PJ_LP lp, PJ *P) { /* Ellipsoidal, forward */

    PJ_XY xy = {0.0, 0.0};

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

    double rh, E, c;

    E = sin(lp.phi);

    c = cos(lp.phi);

    rh = Q->am1 + Q->m1 - pj_mlfn(lp.phi, E, c, Q->en);

    if (fabs(rh) > EPS10) {

        E = c * lp.lam / (rh * sqrt(1. - P->es * E * E));

        xy.x = rh * sin(E);

        xy.y = Q->am1 - rh * cos(E);

    } else {

        xy.x = 0.;

        xy.y = 0.;

    }

    return xy;

}

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

    PJ_XY xy = {0.0, 0.0};

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

    double E, rh;

    rh = Q->cphi1 + Q->phi1 - lp.phi;

    if (fabs(rh) > EPS10) {

        E = lp.lam * cos(lp.phi) / rh;

        xy.x = rh * sin(E);

        xy.y = Q->cphi1 - rh * cos(E);

    } else

        xy.x = xy.y = 0.;

    return xy;

}

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

    PJ_LP lp = {0.0, 0.0};

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

    xy.y = Q->cphi1 - xy.y;

    const double rh = copysign(hypot(xy.x, xy.y), Q->phi1);

    lp.phi = Q->cphi1 + Q->phi1 - rh;

    const double abs_phi = fabs(lp.phi);

    if (abs_phi > M_HALFPI) {

        proj_errno_set(P, PROJ_ERR_COORD_TRANSFM_OUTSIDE_PROJECTION_DOMAIN);

        return lp;

    }

    if (M_HALFPI - abs_phi <= EPS10)

        lp.lam = 0.;

    else {

        const double lm = rh / cos(lp.phi);

        if (Q->phi1 > 0) {

            lp.lam = lm * atan2(xy.x, xy.y);

        } else {

            lp.lam = lm * atan2(-xy.x, -xy.y);

        }

    }

    return lp;

}

static PJ_LP bonne_e_inverse(PJ_XY xy, PJ *P) { /* Ellipsoidal, inverse */

    PJ_LP lp = {0.0, 0.0};

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

    xy.y = Q->am1 - xy.y;

    const double rh = copysign(hypot(xy.x, xy.y), Q->phi1);

    lp.phi = pj_inv_mlfn(Q->am1 + Q->m1 - rh, Q->en);

    const double abs_phi = fabs(lp.phi);

    if (abs_phi < M_HALFPI) {

        const double sinphi = sin(lp.phi);

        const double lm = rh * sqrt(1. - P->es * sinphi * sinphi) / cos(lp.phi);

        if (Q->phi1 > 0) {

            lp.lam = lm * atan2(xy.x, xy.y);

        } else {

            lp.lam = lm * atan2(-xy.x, -xy.y);

        }

    } else if (abs_phi - M_HALFPI <= EPS10)

        lp.lam = 0.;

    else {

        proj_errno_set(P, PROJ_ERR_COORD_TRANSFM_OUTSIDE_PROJECTION_DOMAIN);

        return lp;

    }

    return lp;

}

static PJ *pj_bonne_destructor(PJ *P, int errlev) { /* Destructor */

    if (nullptr == P)

        return nullptr;

    if (nullptr == P->opaque)

        return pj_default_destructor(P, errlev);

    free(static_cast<struct pj_bonne_data *>(P->opaque)->en);

    return pj_default_destructor(P, errlev);

}

PJ *PJ_PROJECTION(bonne) {

    double c;

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

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

    if (nullptr == Q)

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

    P->opaque = Q;

    P->destructor = pj_bonne_destructor;

    Q->phi1 = pj_param(P->ctx, P->params, "rlat_1").f;

    if (fabs(Q->phi1) < EPS10) {

        proj_log_error(P, _("Invalid value for lat_1: |lat_1| should be > 0"));

        return pj_bonne_destructor(P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);

    }

    if (P->es != 0.0) {

        Q->en = pj_enfn(P->n);

        if (nullptr == Q->en)

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

        Q->am1 = sin(Q->phi1);

        c = cos(Q->phi1);

        Q->m1 = pj_mlfn(Q->phi1, Q->am1, c, Q->en);

        Q->am1 = c / (sqrt(1. - P->es * Q->am1 * Q->am1) * Q->am1);

        P->inv = bonne_e_inverse;

        P->fwd = bonne_e_forward;

    } else {

        if (fabs(Q->phi1) + EPS10 >= M_HALFPI)

            Q->cphi1 = 0.;

        else

            Q->cphi1 = 1. / tan(Q->phi1);

        P->inv = bonne_s_inverse;

        P->fwd = bonne_s_forward;

    }

    return P;

}

#undef EPS10