/*
 * Copyright 2005-2018 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      = accessor
   SUPER      = grib_accessor_class_double
   IMPLEMENTS = unpack_double;
   IMPLEMENTS = value_count
   IMPLEMENTS = init
   MEMBERS =const char* values
   MEMBERS =long distinct
   MEMBERS =double* lats
   MEMBERS =long size
   MEMBERS =int save
   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 "accessor.class" and rerun ./make_class.pl

*/

static int unpack_double(grib_accessor*, double* val,size_t *len);
static int value_count(grib_accessor*,long*);
static void init(grib_accessor*,const long, grib_arguments* );
static void init_class(grib_accessor_class*);

typedef struct grib_accessor_latitudes {
    grib_accessor          att;
/* Members defined in gen */
/* Members defined in double */
/* Members defined in latitudes */
	const char* values;
	long distinct;
	double* lats;
	long size;
	int save;
} grib_accessor_latitudes;

extern grib_accessor_class* grib_accessor_class_double;

static grib_accessor_class _grib_accessor_class_latitudes = {
    &grib_accessor_class_double,                      /* super                     */
    "latitudes",                      /* name                      */
    sizeof(grib_accessor_latitudes),  /* size                      */
    0,                           /* inited */
    &init_class,                 /* init_class */
    &init,                       /* init                      */
    0,                  /* post_init                      */
    0,                    /* free mem                       */
    0,                       /* describes himself         */
    0,                /* get length of section     */
    0,              /* get length of string      */
    &value_count,                /* get number of values      */
    0,                 /* get number of bytes      */
    0,                /* get offset to bytes           */
    0,            /* get native type               */
    0,                /* get sub_section                */
    0,               /* grib_pack procedures long      */
    0,                 /* grib_pack procedures long      */
    0,                  /* grib_pack procedures long      */
    0,                /* grib_unpack procedures long    */
    0,                /* grib_pack procedures double    */
    &unpack_double,              /* grib_unpack procedures double  */
    0,                /* grib_pack procedures string    */
    0,              /* grib_unpack procedures string  */
    0,          /* grib_pack array procedures string    */
    0,        /* grib_unpack array procedures string  */
    0,                 /* grib_pack procedures bytes     */
    0,               /* grib_unpack procedures bytes   */
    0,            /* pack_expression */
    0,              /* notify_change   */
    0,                /* update_size   */
    0,            /* preferred_size   */
    0,                    /* resize   */
    0,      /* nearest_smaller_value */
    0,                       /* next accessor    */
    0,                    /* compare vs. another accessor   */
    0,     /* unpack only ith value          */
    0,     /* unpack a subarray         */
    0,              		/* clear          */
    0,               		/* clone accessor          */
};


grib_accessor_class* grib_accessor_class_latitudes = &_grib_accessor_class_latitudes;


static void init_class(grib_accessor_class* c)
{
	c->dump	=	(*(c->super))->dump;
	c->next_offset	=	(*(c->super))->next_offset;
	c->string_length	=	(*(c->super))->string_length;
	c->byte_count	=	(*(c->super))->byte_count;
	c->byte_offset	=	(*(c->super))->byte_offset;
	c->get_native_type	=	(*(c->super))->get_native_type;
	c->sub_section	=	(*(c->super))->sub_section;
	c->pack_missing	=	(*(c->super))->pack_missing;
	c->is_missing	=	(*(c->super))->is_missing;
	c->pack_long	=	(*(c->super))->pack_long;
	c->unpack_long	=	(*(c->super))->unpack_long;
	c->pack_double	=	(*(c->super))->pack_double;
	c->pack_string	=	(*(c->super))->pack_string;
	c->unpack_string	=	(*(c->super))->unpack_string;
	c->pack_string_array	=	(*(c->super))->pack_string_array;
	c->unpack_string_array	=	(*(c->super))->unpack_string_array;
	c->pack_bytes	=	(*(c->super))->pack_bytes;
	c->unpack_bytes	=	(*(c->super))->unpack_bytes;
	c->pack_expression	=	(*(c->super))->pack_expression;
	c->notify_change	=	(*(c->super))->notify_change;
	c->update_size	=	(*(c->super))->update_size;
	c->preferred_size	=	(*(c->super))->preferred_size;
	c->resize	=	(*(c->super))->resize;
	c->nearest_smaller_value	=	(*(c->super))->nearest_smaller_value;
	c->next	=	(*(c->super))->next;
	c->compare	=	(*(c->super))->compare;
	c->unpack_double_element	=	(*(c->super))->unpack_double_element;
	c->unpack_double_subarray	=	(*(c->super))->unpack_double_subarray;
	c->clear	=	(*(c->super))->clear;
	c->make_clone	=	(*(c->super))->make_clone;
}

/* END_CLASS_IMP */


static int get_distinct(grib_accessor* a,double** val,long* len);

static int compare_doubles( const void* a, const void* b, int ascending ) {
    /* ascending is a boolean: 0 or 1 */
    double* arg1 = (double*) a;
    double* arg2 = (double*) b;
    if (ascending) {
        if( *arg1 < *arg2 ) return -1;		/*Smaller values come before larger ones*/
    } else {
        if( *arg1 > *arg2 ) return -1;		/*Larger values come before smaller ones*/
    }
    if( *arg1 == *arg2 ) return 0;
    else return 1;
}
static int compare_doubles_ascending( const void* a, const void* b ) {
    return compare_doubles(a,b,1);
}
static int compare_doubles_descending( const void* a, const void* b ) {
    return compare_doubles(a,b,0);
}

static void init(grib_accessor* a,const long l, grib_arguments* c)
{
    grib_accessor_latitudes* self = (grib_accessor_latitudes*)a;
    int n = 0;

    self->values = grib_arguments_get_name(grib_handle_of_accessor(a),c,n++);
    self->distinct = grib_arguments_get_long(grib_handle_of_accessor(a),c,n++);
    self->save=0;

    a->flags |= GRIB_ACCESSOR_FLAG_READ_ONLY;
}

static int unpack_double(grib_accessor* a, double* val, size_t *len)
{
    grib_context* c=a->context;
    grib_accessor_latitudes* self = (grib_accessor_latitudes*)a;
    int ret = 0;
    double* v=val;
    double dummyLon=0, dummyVal=0;
    size_t size=0;
    long count=0;
    grib_iterator* iter=NULL;

    self->save=1;
    size=0;
    ret=value_count(a,&count);
    if (ret) return ret;
    size=count;
    if (*len<size) {
        /* self->lats are computed in value_count so must free */
        if (self->lats) {
            grib_context_free(c,self->lats);
            self->lats=NULL;
        }
        return GRIB_ARRAY_TOO_SMALL;
    }
    self->save=0;

    /* self->lats are computed in value_count*/
    if (self->lats) {
        int i;
        *len=self->size;
        for (i=0;i<size;i++) val[i]=self->lats[i];
        grib_context_free(c,self->lats);
        self->lats=NULL;
        self->size=0;
        return GRIB_SUCCESS;
    }

    iter=grib_iterator_new(grib_handle_of_accessor(a),0,&ret);
    if (ret!=GRIB_SUCCESS) {
        if (iter) grib_iterator_delete(iter);
        grib_context_log(c,GRIB_LOG_ERROR,"unable to create iterator");
        return ret;
    }

    while(grib_iterator_next(iter,v++,&dummyLon,&dummyVal)) {}
    grib_iterator_delete(iter);

    *len=size;

    return ret;
}

static int value_count(grib_accessor* a,long* len)
{
    grib_accessor_latitudes* self = (grib_accessor_latitudes*)a;
    grib_handle* h=grib_handle_of_accessor(a);
    grib_context* c=a->context;
    double* val=NULL;
    int ret;
    size_t size;

    *len=0;
    if ((ret=grib_get_size(h,self->values,&size))!=GRIB_SUCCESS) {
        grib_context_log(h->context,GRIB_LOG_ERROR,"unable to get size of %s",self->values);
        return ret;
    }
    *len=size;

    if (self->distinct) {
        ret=get_distinct(a,&val,len);
        if (ret!=GRIB_SUCCESS) return ret;
        if (self->save) {
            self->lats=val;
            self->size=*len;
        } else {
            grib_context_free(c,val);
        }
    }

    return ret;
}

static int get_distinct(grib_accessor* a,double** val,long* len) {
    long count=0;
    double prev;
    double *v=NULL;
    double *v1=NULL;
    double dummyLon=0, dummyVal=0;
    int ret=0;
    int i;
    long jScansPositively=0; /*default: north to south*/
    size_t size=*len;
    grib_context* c=a->context;
    grib_iterator* iter=grib_iterator_new(grib_handle_of_accessor(a),0,&ret);
    if (ret!=GRIB_SUCCESS) {
        if (iter) grib_iterator_delete(iter);
        grib_context_log(c,GRIB_LOG_ERROR,"unable to create iterator");
        return ret;
    }
    v=(double*)grib_context_malloc_clear(c,size*sizeof(double));
    if (!v) {
        grib_context_log(c,GRIB_LOG_ERROR,
                "unable to allocate %ld bytes",(long)size*sizeof(double));
        return GRIB_OUT_OF_MEMORY;
    }
    *val=v;

    while(grib_iterator_next(iter,v++,&dummyLon,&dummyVal)) {}
    grib_iterator_delete(iter);
    v=*val;

    /* See which direction the latitudes are to be scanned */
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a), "jScansPositively", &jScansPositively))) return ret;
    if (jScansPositively) {
        qsort(v,*len,sizeof(double),&compare_doubles_ascending);		/*South to North*/
    } else {
        qsort(v,*len,sizeof(double),&compare_doubles_descending);		/*North to South*/
    }

    v1=(double*)grib_context_malloc_clear(c,size*sizeof(double));
    if (!v1) {
        grib_context_log(c,GRIB_LOG_ERROR, "unable to allocate %ld bytes",(long)size*sizeof(double));
        return GRIB_OUT_OF_MEMORY;
    }

    /*Construct a unique set of lats by filtering out duplicates*/
    prev=v[0];
    v1[0]=prev;
    count=1;
    for (i=1;i<*len;i++) {
        if (v[i]!=prev) {
            prev=v[i];
            v1[count]=prev;		/*Value different from previous so store it*/
            count++;
        }
    }

    grib_context_free(c,v);

    *val=v1;

    *len=count;
    return GRIB_SUCCESS;
}
