#include <errno.h>

#include <math.h>

#include <stddef.h>

#include <string.h>

#include "proj.h"

#include "proj_internal.h"

namespace { // anonymous namespace

struct pj_ob_tran_data {

    struct PJconsts *link;

    double lamp;

    double cphip, sphip;

};

} // anonymous namespace

PROJ_HEAD(ob_tran, "General Oblique Transformation")

"\n\tMisc Sph"

    "\n\to_proj= plus parameters for projection"

    "\n\to_lat_p= o_lon_p= (new pole) or"

    "\n\to_alpha= o_lon_c= o_lat_c= or"

    "\n\to_lon_1= o_lat_1= o_lon_2= o_lat_2=";

#define TOL 1e-10

static PJ_XY o_forward(PJ_LP lp, PJ *P) { /* spheroid */

    struct pj_ob_tran_data *Q =

        static_cast<struct pj_ob_tran_data *>(P->opaque);

    double coslam, sinphi, cosphi;

    coslam = cos(lp.lam);

    sinphi = sin(lp.phi);

    cosphi = cos(lp.phi);

    /* Formula (5-8b) of Snyder's "Map projections: a working manual" */

    lp.lam = adjlon(aatan2(cosphi * sin(lp.lam),

                           Q->sphip * cosphi * coslam + Q->cphip * sinphi) +

                    Q->lamp);

    /* Formula (5-7) */

    lp.phi = aasin(P->ctx, Q->sphip * sinphi - Q->cphip * cosphi * coslam);

    return Q->link->fwd(lp, Q->link);

}

static PJ_XY t_forward(PJ_LP lp, PJ *P) { /* spheroid */

    struct pj_ob_tran_data *Q =

        static_cast<struct pj_ob_tran_data *>(P->opaque);

    double cosphi, coslam;

    cosphi = cos(lp.phi);

    coslam = cos(lp.lam);

    lp.lam = adjlon(aatan2(cosphi * sin(lp.lam), sin(lp.phi)) + Q->lamp);

    lp.phi = aasin(P->ctx, -cosphi * coslam);

    return Q->link->fwd(lp, Q->link);

}

static PJ_LP o_inverse(PJ_XY xy, PJ *P) { /* spheroid */

    struct pj_ob_tran_data *Q =

        static_cast<struct pj_ob_tran_data *>(P->opaque);

    double coslam, sinphi, cosphi;

    PJ_LP lp = Q->link->inv(xy, Q->link);

    if (lp.lam != HUGE_VAL) {

        lp.lam -= Q->lamp;

        coslam = cos(lp.lam);

        sinphi = sin(lp.phi);

        cosphi = cos(lp.phi);

        /* Formula (5-9) */

        lp.phi = aasin(P->ctx, Q->sphip * sinphi + Q->cphip * cosphi * coslam);

        /* Formula (5-10b) */

        lp.lam = aatan2(cosphi * sin(lp.lam),

                        Q->sphip * cosphi * coslam - Q->cphip * sinphi);

    }

    return lp;

}

static PJ_LP t_inverse(PJ_XY xy, PJ *P) { /* spheroid */

    struct pj_ob_tran_data *Q =

        static_cast<struct pj_ob_tran_data *>(P->opaque);

    double cosphi, t;

    PJ_LP lp = Q->link->inv(xy, Q->link);

    if (lp.lam != HUGE_VAL) {

        cosphi = cos(lp.phi);

        t = lp.lam - Q->lamp;

        lp.lam = aatan2(cosphi * sin(t), -sin(lp.phi));

        lp.phi = aasin(P->ctx, cosphi * cos(t));

    }

    return lp;

}

static PJ *destructor(PJ *P, int errlev) {

    if (nullptr == P)

        return nullptr;

    if (nullptr == P->opaque)

        return pj_default_destructor(P, errlev);

    if (static_cast<struct pj_ob_tran_data *>(P->opaque)->link)

        static_cast<struct pj_ob_tran_data *>(P->opaque)->link->destructor(

            static_cast<struct pj_ob_tran_data *>(P->opaque)->link, errlev);

    return pj_default_destructor(P, errlev);

}

/***********************************************************************

These functions are modified versions of the functions "argc_params"

and "argv_params" from PJ_pipeline.c

Basically, they do the somewhat backwards stunt of turning the paralist

representation of the +args back into the original +argv, +argc

representation accepted by pj_init_ctx().

This, however, also begs the question of whether we really need the

paralist linked list representation, or if we could do with a simpler

null-terminated argv style array? This would simplify some code, and

keep memory allocations more localized.

***********************************************************************/

typedef struct {

    int argc;

    char **argv;

} ARGS;

/* count the number of args in the linked list <params> */

static size_t paralist_params_argc(paralist *params) {

    size_t argc = 0;

    for (; params != nullptr; params = params->next)

        argc++;

    return argc;

}

/* turn paralist into argc/argv style argument list */

static ARGS ob_tran_target_params(paralist *params) {

    int i = 0;

    ARGS args = {0, nullptr};

    size_t argc = paralist_params_argc(params);

    if (argc < 2)

        return args;

    /* all args except the proj=ob_tran */

    args.argv = static_cast<char **>(calloc(argc - 1, sizeof(char *)));

    if (nullptr == args.argv)

        return args;

    /* Copy all args *except* the proj=ob_tran or inv arg to the argv array */

    for (i = 0; params != nullptr; params = params->next) {

        if (0 == strcmp(params->param, "proj=ob_tran") ||

            0 == strcmp(params->param, "inv"))

            continue;

        args.argv[i++] = params->param;

    }

    args.argc = i;

    /* Then convert the o_proj=xxx element to proj=xxx */

    for (i = 0; i < args.argc; i++) {

        if (0 != strncmp(args.argv[i], "o_proj=", 7))

            continue;

        args.argv[i] += 2;

        if (strcmp(args.argv[i], "proj=ob_tran") == 0) {

            free(args.argv);

            args.argc = 0;

            args.argv = nullptr;

        }

        break;

    }

    return args;

}

PJ *PJ_PROJECTION(ob_tran) {

    double phip;

    ARGS args;

    PJ *R; /* projection to rotate */

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

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

    if (nullptr == Q)

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

    P->opaque = Q;

    P->destructor = destructor;

    /* get name of projection to be translated */

    if (pj_param(P->ctx, P->params, "so_proj").s == nullptr) {

        proj_log_error(P, _("Missing parameter: o_proj"));

        return destructor(P, PROJ_ERR_INVALID_OP_MISSING_ARG);

    }

    /* Create the target projection object to rotate */

    args = ob_tran_target_params(P->params);

    /* avoid endless recursion */

    if (args.argv == nullptr) {

        proj_log_error(P, _("Failed to find projection to be rotated"));

        return destructor(P, PROJ_ERR_INVALID_OP_MISSING_ARG);

    }

    R = pj_create_argv_internal(P->ctx, args.argc, args.argv);

    free(args.argv);

    if (nullptr == R) {

        proj_log_error(P, _("Projection to be rotated is unknown"));

        return destructor(P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);

    }

    // Transfer the used flag from the R object to the P object

    for (auto p = P->params; p; p = p->next) {

        if (!p->used) {

            for (auto r = R->params; r; r = r->next) {

                if (r->used && strcmp(r->param, p->param) == 0) {

                    p->used = 1;

                    break;

                }

            }

        }

    }

    Q->link = R;

    if (pj_param(P->ctx, P->params, "to_alpha").i) {

        double lamc, phic, alpha;

        lamc = pj_param(P->ctx, P->params, "ro_lon_c").f;

        phic = pj_param(P->ctx, P->params, "ro_lat_c").f;

        alpha = pj_param(P->ctx, P->params, "ro_alpha").f;

        if (fabs(fabs(phic) - M_HALFPI) <= TOL) {

            proj_log_error(

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

            return destructor(P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);

        }

        Q->lamp = lamc + aatan2(-cos(alpha), -sin(alpha) * sin(phic));

        phip = aasin(P->ctx, cos(phic) * sin(alpha));

    } else if (pj_param(P->ctx, P->params, "to_lat_p")

                   .i) { /* specified new pole */

        Q->lamp = pj_param(P->ctx, P->params, "ro_lon_p").f;

        phip = pj_param(P->ctx, P->params, "ro_lat_p").f;

    } else { /* specified new "equator" points */

        double lam1, lam2, phi1, phi2, con;

        lam1 = pj_param(P->ctx, P->params, "ro_lon_1").f;

        phi1 = pj_param(P->ctx, P->params, "ro_lat_1").f;

        lam2 = pj_param(P->ctx, P->params, "ro_lon_2").f;

        phi2 = pj_param(P->ctx, P->params, "ro_lat_2").f;

        con = fabs(phi1);

        if (fabs(phi1) > M_HALFPI - TOL) {

            proj_log_error(

                P, _("Invalid value for lat_1: |lat_1| should be < 90°"));

            return destructor(P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);

        }

        if (fabs(phi2) > M_HALFPI - TOL) {

            proj_log_error(

                P, _("Invalid value for lat_2: |lat_2| should be < 90°"));

            return destructor(P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);

        }

        if (fabs(phi1 - phi2) < TOL) {

            proj_log_error(

                P, _("Invalid value for lat_1 and lat_2: lat_1 should be "

                     "different from lat_2"));

            return destructor(P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);

        }

        if (con < TOL) {

            proj_log_error(P, _("Invalid value for lat_1: lat_1 should be "

                                "different from zero"));

            return destructor(P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);

        }

        Q->lamp = atan2(cos(phi1) * sin(phi2) * cos(lam1) -

                            sin(phi1) * cos(phi2) * cos(lam2),

                        sin(phi1) * cos(phi2) * sin(lam2) -

                            cos(phi1) * sin(phi2) * sin(lam1));

        phip = atan(-cos(Q->lamp - lam1) / tan(phi1));

    }

    if (fabs(phip) > TOL) { /* oblique */

        Q->cphip = cos(phip);

        Q->sphip = sin(phip);

        P->fwd = Q->link->fwd ? o_forward : nullptr;

        P->inv = Q->link->inv ? o_inverse : nullptr;

    } else { /* transverse */

        P->fwd = Q->link->fwd ? t_forward : nullptr;

        P->inv = Q->link->inv ? t_inverse : nullptr;

    }

    /* Support some rather speculative test cases, where the rotated projection

     */

    /* is actually latlong. We do not want scaling in that case... */

    if (Q->link->right == PJ_IO_UNITS_RADIANS)

        P->right = PJ_IO_UNITS_WHATEVER;

    return P;

}

#undef TOL