/*
 * (C) Copyright 2005- ECMWF.
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 *
 * In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
 * virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
 */

#include "grib_api_internal.h"

/*
   This is used by make_class.pl

   START_CLASS_DEF
   CLASS      = nearest
   SUPER      = grib_nearest_class_gen
   IMPLEMENTS = init;destroy;find
   MEMBERS    = double* lats
   MEMBERS    = int  lats_count
   MEMBERS    = double* lons
   MEMBERS    = double* distances
   MEMBERS    = int* k
   MEMBERS    = int* j
   MEMBERS    = const char* Nj
   MEMBERS    = const char* pl
   MEMBERS    = const char* lonFirst
   MEMBERS    = const char* lonLast
   END_CLASS_DEF

 */

/* START_CLASS_IMP */

/*

Don't edit anything between START_CLASS_IMP and END_CLASS_IMP
Instead edit values between START_CLASS_DEF and END_CLASS_DEF
or edit "nearest.class" and rerun ./make_class.pl

*/


static void init_class(grib_nearest_class*);

static int init(grib_nearest* nearest, grib_handle* h, grib_arguments* args);
static int find(grib_nearest* nearest, grib_handle* h, double inlat, double inlon, unsigned long flags, double* outlats, double* outlons, double* values, double* distances, int* indexes, size_t* len);
static int destroy(grib_nearest* nearest);

typedef struct grib_nearest_latlon_reduced
{
    grib_nearest nearest;
    /* Members defined in gen */
    const char* values_key;
    const char* radius;
    int cargs;
    /* Members defined in latlon_reduced */
    double* lats;
    int lats_count;
    double* lons;
    double* distances;
    int* k;
    int* j;
    const char* Nj;
    const char* pl;
    const char* lonFirst;
    const char* lonLast;
} grib_nearest_latlon_reduced;

extern grib_nearest_class* grib_nearest_class_gen;

static grib_nearest_class _grib_nearest_class_latlon_reduced = {
    &grib_nearest_class_gen,             /* super                     */
    "latlon_reduced",                    /* name                      */
    sizeof(grib_nearest_latlon_reduced), /* size of instance          */
    0,                                   /* inited */
    &init_class,                         /* init_class */
    &init,                               /* constructor               */
    &destroy,                            /* destructor                */
    &find,                               /* find nearest              */
};

grib_nearest_class* grib_nearest_class_latlon_reduced = &_grib_nearest_class_latlon_reduced;


static void init_class(grib_nearest_class* c)
{
}
/* END_CLASS_IMP */

static int init(grib_nearest* nearest, grib_handle* h, grib_arguments* args)
{
    grib_nearest_latlon_reduced* self = (grib_nearest_latlon_reduced*)nearest;
    self->Nj                          = grib_arguments_get_name(h, args, self->cargs++);
    self->pl                          = grib_arguments_get_name(h, args, self->cargs++);
    self->lonFirst                    = grib_arguments_get_name(h, args, self->cargs++);
    self->lonLast                     = grib_arguments_get_name(h, args, self->cargs++);
    self->j                           = (int*)grib_context_malloc(h->context, 2 * sizeof(int));
    if (!self->j)
        return GRIB_OUT_OF_MEMORY;
    self->k = (int*)grib_context_malloc(nearest->context, 4 * sizeof(int));
    if (!self->k)
        return GRIB_OUT_OF_MEMORY;

    return 0;
}

static int find(grib_nearest* nearest, grib_handle* h,
                double inlat, double inlon, unsigned long flags,
                double* outlats, double* outlons, double* values,
                double* distances, int* indexes, size_t* len)
{
    grib_nearest_latlon_reduced* self = (grib_nearest_latlon_reduced*)nearest;
    int ret = 0, kk = 0, ii = 0, jj = 0;
    int j               = 0;
    long* pla           = NULL;
    long* pl            = NULL;
    size_t nvalues      = 0;
    grib_iterator* iter = NULL;
    double lat = 0, lon = 0;
    double radiusInKm;
    int ilat = 0, ilon = 0;

    if ((ret = grib_get_size(h, self->values_key, &nvalues)) != GRIB_SUCCESS)
        return ret;
    nearest->values_count = nvalues;

    if ((ret = grib_nearest_get_radius(h, &radiusInKm)) != GRIB_SUCCESS)
        return ret;

    /* Compute lat/lon info, create iterator etc if it's the 1st time or different grid.
     * This is for performance: if the grid has not changed, we only do this once
     * and reuse for other messages */
    if (!nearest->h || (flags & GRIB_NEAREST_SAME_GRID) == 0) {
        double dummy = 0;
        double olat  = 1.e10;
        long n       = 0;

        ilat = 0;
        ilon = 0;
        if (grib_is_missing(h, self->Nj, &ret)) {
            grib_context_log(h->context, GRIB_LOG_DEBUG, "Key '%s' is missing", self->Nj);
            return ret ? ret : GRIB_GEOCALCULUS_PROBLEM;
        }

        if ((ret = grib_get_long(h, self->Nj, &n)) != GRIB_SUCCESS)
            return ret;
        self->lats_count = n;

        if (self->lats)
            grib_context_free(nearest->context, self->lats);
        self->lats = (double*)grib_context_malloc(nearest->context,
                                                  self->lats_count * sizeof(double));
        if (!self->lats)
            return GRIB_OUT_OF_MEMORY;

        if (self->lons)
            grib_context_free(nearest->context, self->lons);
        self->lons = (double*)grib_context_malloc(nearest->context,
                                                  nearest->values_count * sizeof(double));
        if (!self->lons)
            return GRIB_OUT_OF_MEMORY;

        iter = grib_iterator_new(h, 0, &ret);
        if (ret) {
            grib_context_log(h->context, GRIB_LOG_ERROR, "unable to create iterator");
            return ret;
        }
        while (grib_iterator_next(iter, &lat, &lon, &dummy)) {
            if (olat != lat) {
                self->lats[ilat++] = lat;
                olat               = lat;
            }
            self->lons[ilon++] = lon;
        }
        self->lats_count = ilat;
        grib_iterator_delete(iter);
    }
    nearest->h = h;

    /* Compute distances if it's the 1st time or different point or different grid.
     * This is for performance: if the grid and the input point have not changed
     * we only do this once and reuse for other messages */
    if (!self->distances || (flags & GRIB_NEAREST_SAME_POINT) == 0 || (flags & GRIB_NEAREST_SAME_GRID) == 0) {
        double* lons           = NULL;
        int nlon               = 0;
        size_t plsize          = 0;
        long nplm1             = 0;
        int nearest_lons_found = 0;
        double lon_first, lon_last;
        int islocal = 0;
        long plmax;
        double dimin;

        if ((ret = grib_get_double(h, self->lonFirst, &lon_first)) != GRIB_SUCCESS) {
            grib_context_log(h->context, GRIB_LOG_ERROR,
                             "grib_nearest_latlon_reduced.find(): unable to get %s %s\n", self->lonFirst,
                             grib_get_error_message(ret));
            return ret;
        }
        if ((ret = grib_get_double(h, self->lonLast, &lon_last)) != GRIB_SUCCESS) {
            grib_context_log(h->context, GRIB_LOG_ERROR,
                             "grib_nearest_latlon_reduced.find(): unable to get %s %s\n", self->lonLast,
                             grib_get_error_message(ret));
            return ret;
        }

        plsize = self->lats_count;
        if ((ret = grib_get_size(h, self->pl, &plsize)) != GRIB_SUCCESS)
            return ret;
        pla = (long*)grib_context_malloc(h->context, plsize * sizeof(long));
        if (!pla)
            return GRIB_OUT_OF_MEMORY;
        if ((ret = grib_get_long_array(h, self->pl, pla, &plsize)) != GRIB_SUCCESS)
            return ret;

        pl = pla;
        while ((*pl) == 0) {
            pl++;
        }

        plmax = pla[0];
        for (j = 0; j < plsize; j++)
            if (plmax < pla[j])
                plmax = pla[j];
        dimin = 360.0 / plmax;

        if (360 - fabs(lon_last - lon_first) < 2 * dimin) {
            islocal = 0;
        }
        else {
            islocal = 1;
        }

        if (islocal)
            for (j = 0; j < plsize; j++)
                pla[j]--;

        /* printf("XXXX islocal=%d\n",islocal); */
        while (inlon < 0)
            inlon += 360;
        while (inlon > 360)
            inlon -= 360;

        ilat = self->lats_count;
        if (self->lats[ilat - 1] > self->lats[0]) {
            if (inlat < self->lats[0] || inlat > self->lats[ilat - 1])
                return GRIB_OUT_OF_AREA;
        }
        else {
            if (inlat > self->lats[0] || inlat < self->lats[ilat - 1])
                return GRIB_OUT_OF_AREA;
        }

        if (!self->distances)
            self->distances = (double*)grib_context_malloc(nearest->context, 4 * sizeof(double));
        if (!self->distances)
            return GRIB_OUT_OF_MEMORY;

        grib_binary_search(self->lats, ilat - 1, inlat,
                           &(self->j[0]), &(self->j[1]));

        nlon = 0;
        for (jj = 0; jj < self->j[0]; jj++)
            nlon += pl[jj];
        nplm1 = pl[self->j[0]] - 1;

        lons = self->lons + nlon;

        nearest_lons_found = 0;
        if (lons[nplm1] > lons[0]) {
            if (inlon < lons[0] || inlon > lons[nplm1]) {
                if (lons[nplm1] - lons[0] - 360 <=
                    lons[nplm1] - lons[nplm1 - 1]) {
                    self->k[0]         = 0;
                    self->k[1]         = nplm1;
                    nearest_lons_found = 1;
                }
                else
                    return GRIB_OUT_OF_AREA;
            }
        }
        else {
            if (inlon > lons[0] || inlon < lons[nplm1]) {
                if (lons[0] - lons[nplm1] - 360 <=
                    lons[0] - lons[1]) {
                    self->k[0]         = 0;
                    self->k[1]         = nplm1;
                    nearest_lons_found = 1;
                }
                else
                    return GRIB_OUT_OF_AREA;
            }
        }

        if (!nearest_lons_found) {
            grib_binary_search(lons, pl[self->j[0]] - 1, inlon,
                               &(self->k[0]), &(self->k[1]));
        }
        self->k[0] += nlon;
        self->k[1] += nlon;

        nlon = 0;
        for (jj = 0; jj < self->j[1]; jj++)
            nlon += pl[jj];
        nplm1 = pl[self->j[1]] - 1;

        lons = self->lons + nlon;

        nearest_lons_found = 0;
        if (lons[nplm1] > lons[0]) {
            if (inlon < lons[0] || inlon > lons[nplm1]) {
                if (lons[nplm1] - lons[0] - 360 <=
                    lons[nplm1] - lons[nplm1 - 1]) {
                    self->k[2]         = 0;
                    self->k[3]         = nplm1;
                    nearest_lons_found = 1;
                }
                else
                    return GRIB_OUT_OF_AREA;
            }
        }
        else {
            if (inlon > lons[0] || inlon < lons[nplm1]) {
                if (lons[0] - lons[nplm1] - 360 <=
                    lons[0] - lons[1]) {
                    self->k[2]         = 0;
                    self->k[3]         = nplm1;
                    nearest_lons_found = 1;
                }
                else
                    return GRIB_OUT_OF_AREA;
            }
        }

        if (!nearest_lons_found) {
            grib_binary_search(lons, pl[self->j[1]] - 1, inlon,
                               &(self->k[2]), &(self->k[3]));
        }

        self->k[2] += nlon;
        self->k[3] += nlon;

        kk = 0;
        for (jj = 0; jj < 2; jj++) {
            for (ii = 0; ii < 2; ii++) {
                self->distances[kk] = geographic_distance_spherical(radiusInKm, inlon, inlat,
                                                            self->lons[self->k[kk]], self->lats[self->j[jj]]);
                kk++;
            }
        }

        grib_context_free(h->context, pla);
    }

    kk = 0;
    for (jj = 0; jj < 2; jj++) {
        for (ii = 0; ii < 2; ii++) {
            distances[kk] = self->distances[kk];
            outlats[kk]   = self->lats[self->j[jj]];
            outlons[kk]   = self->lons[self->k[kk]];
            if (values) { /* ECC-499 */
                grib_get_double_element_internal(h, self->values_key, self->k[kk], &(values[kk]));
            }
            indexes[kk] = self->k[kk];
            kk++;
        }
    }

    return GRIB_SUCCESS;
}

static int destroy(grib_nearest* nearest)
{
    grib_nearest_latlon_reduced* self = (grib_nearest_latlon_reduced*)nearest;
    if (self->lats)
        grib_context_free(nearest->context, self->lats);
    if (self->lons)
        grib_context_free(nearest->context, self->lons);
    if (self->j)
        grib_context_free(nearest->context, self->j);
    if (self->k)
        grib_context_free(nearest->context, self->k);
    if (self->distances)
        grib_context_free(nearest->context, self->distances);

    return GRIB_SUCCESS;
}
