/*
 * Copyright 2005-2017 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"
#include <math.h>
/*
   This is used by make_class.pl

   START_CLASS_DEF
   CLASS      = accessor
   SUPER      = grib_accessor_class_data_simple_packing
   IMPLEMENTS = unpack_double
   IMPLEMENTS = value_count
   IMPLEMENTS = init
   MEMBERS= const char*  GRIBEX_sh_bug_present
   MEMBERS= const char*  ieee_floats
   MEMBERS= const char*  laplacianOperatorIsSet
   MEMBERS= const char*  laplacianOperator
   MEMBERS= const char*  sub_j
   MEMBERS= const char*  sub_k
   MEMBERS= const char*  sub_m
   MEMBERS= const char*  pen_j
   MEMBERS= const char*  pen_k
   MEMBERS= const char*  pen_m
   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_data_sh_packed {
    grib_accessor          att;
/* Members defined in gen */
/* Members defined in values */
	int  carg;
	const char* seclen;
	const char* offsetdata;
	const char* offsetsection;
	int dirty;
/* Members defined in data_simple_packing */
	int edition;
	const char*  units_factor;
	const char*  units_bias;
	const char*  changing_precision;
	const char*  number_of_values;
	const char*  bits_per_value;
	const char*  reference_value;
	const char*  binary_scale_factor;
	const char*  decimal_scale_factor;
	const char*  optimize_scaling_factor;
/* Members defined in data_sh_packed */
	const char*  GRIBEX_sh_bug_present;
	const char*  ieee_floats;
	const char*  laplacianOperatorIsSet;
	const char*  laplacianOperator;
	const char*  sub_j;
	const char*  sub_k;
	const char*  sub_m;
	const char*  pen_j;
	const char*  pen_k;
	const char*  pen_m;
} grib_accessor_data_sh_packed;

extern grib_accessor_class* grib_accessor_class_data_simple_packing;

static grib_accessor_class _grib_accessor_class_data_sh_packed = {
    &grib_accessor_class_data_simple_packing,                      /* super                     */
    "data_sh_packed",                      /* name                      */
    sizeof(grib_accessor_data_sh_packed),  /* 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_data_sh_packed = &_grib_accessor_class_data_sh_packed;


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 */

typedef unsigned long (*encode_float_proc)(double);
typedef double        (*decode_float_proc)(unsigned long);

static void init(grib_accessor* a,const long v, grib_arguments* args)
{
    grib_accessor_data_sh_packed *self =(grib_accessor_data_sh_packed*)a;

    self->GRIBEX_sh_bug_present     = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
    self->ieee_floats               = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
    self->laplacianOperatorIsSet    = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
    self->laplacianOperator         = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
    self->sub_j                     = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
    self->sub_k                     = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
    self->sub_m                     = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
    self->pen_j                     = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
    self->pen_k                     = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);
    self->pen_m                     = grib_arguments_get_name(grib_handle_of_accessor(a),args,self->carg++);

    a->flags |= GRIB_ACCESSOR_FLAG_DATA;
    a->length=0;
}

static int value_count(grib_accessor* a,long* count)
{
    grib_accessor_data_sh_packed *self =(grib_accessor_data_sh_packed*)a;
    int ret = 0;

    long   sub_j= 0;
    long   sub_k= 0;
    long   sub_m= 0;
    long   pen_j= 0;
    long   pen_k= 0;
    long   pen_m= 0;

    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->sub_j,&sub_j)) != GRIB_SUCCESS)
        return ret;
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->sub_k,&sub_k)) != GRIB_SUCCESS)
        return ret;
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->sub_m,&sub_m)) != GRIB_SUCCESS)
        return ret;

    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->pen_j,&pen_j)) != GRIB_SUCCESS)
        return ret;
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->pen_k,&pen_k)) != GRIB_SUCCESS)
        return ret;
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->pen_m,&pen_m)) != GRIB_SUCCESS)
        return ret;

    if (pen_j != pen_k || pen_j!=pen_m ) {
        grib_context_log(a->context,GRIB_LOG_ERROR,"pen_j=%ld, pen_k=%ld, pen_m=%ld\n",pen_j,pen_k,pen_m);
        Assert ((pen_j ==  pen_k) && (pen_j == pen_m));
    }
    *count=(pen_j+1)*(pen_j+2)-(sub_j+1)*(sub_j+2);
    return ret;
}

static int  unpack_double(grib_accessor* a, double* val, size_t *len)
{
    grib_accessor_data_sh_packed* self =  (grib_accessor_data_sh_packed*)a;

    size_t i = 0;
    int ret = GRIB_SUCCESS;
    long   hcount = 0;
    long   lcount = 0;
    long   hpos = 0;
    long   lup = 0;
    long   mmax = 0;
    long   n_vals = 0;
    double *scals  = NULL;
    /* double *pscals=NULL; */
    double dummy=0;

    double s = 0;
    double d = 0;
    double laplacianOperator = 0;
    unsigned char* buf = NULL;
    unsigned char* hres = NULL;
    unsigned char* lres = NULL;
    unsigned long packed_offset;
    long   lpos = 0;

    long   maxv = 0;
    long   GRIBEX_sh_bug_present =0;
    long ieee_floats  = 0;

    long   offsetdata           = 0;
    long   bits_per_value          = 0;
    double reference_value      = 0;
    long   binary_scale_factor         = 0;
    long   decimal_scale_factor = 0;

    long   sub_j= 0;
    long   sub_k= 0;
    long   sub_m= 0;
    long   pen_j= 0;
    long   pen_k= 0;
    long   pen_m= 0;

    double operat= 0;
    int bytes;
    int err=0;

    decode_float_proc decode_float = NULL;

    n_vals = 0;
    err=grib_value_count(a,&n_vals);
    if (err) return err;

    if(*len < n_vals){
        *len = n_vals;
        return GRIB_ARRAY_TOO_SMALL;
    }

    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->offsetdata,&offsetdata))
            != GRIB_SUCCESS)   return ret;
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->bits_per_value,&bits_per_value))
            != GRIB_SUCCESS)   return ret;
    if((ret = grib_get_double_internal(grib_handle_of_accessor(a),self->reference_value,&reference_value))
            != GRIB_SUCCESS)   return ret;
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->binary_scale_factor,&binary_scale_factor))
            != GRIB_SUCCESS)           return ret;

    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->decimal_scale_factor,&decimal_scale_factor))
            != GRIB_SUCCESS)
        return ret;

    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->GRIBEX_sh_bug_present,&GRIBEX_sh_bug_present))
            != GRIB_SUCCESS)
        return ret;

    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->ieee_floats,&ieee_floats)) != GRIB_SUCCESS)
        return ret;

    if((ret = grib_get_double_internal(grib_handle_of_accessor(a),self->laplacianOperator,&laplacianOperator))
            != GRIB_SUCCESS)
        return ret;
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->sub_j,&sub_j)) != GRIB_SUCCESS)
        return ret;
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->sub_k,&sub_k)) != GRIB_SUCCESS)
        return ret;
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->sub_m,&sub_m)) != GRIB_SUCCESS)
        return ret;
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->pen_j,&pen_j)) != GRIB_SUCCESS)
        return ret;
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->pen_k,&pen_k)) != GRIB_SUCCESS)
        return ret;
    if((ret = grib_get_long_internal(grib_handle_of_accessor(a),self->pen_m,&pen_m)) != GRIB_SUCCESS)
        return ret;

    self->dirty=0;

    switch (ieee_floats) {
    case 0:
        decode_float=grib_long_to_ibm;
        bytes=4;
        break;
    case 1:
        decode_float=grib_long_to_ieee;
        bytes=4;
        break;
    case 2:
        decode_float=grib_long_to_ieee64;
        bytes=8;
        break;
    default:
        return GRIB_NOT_IMPLEMENTED;
    }

    Assert (sub_j == sub_k);
    Assert (sub_j == sub_m);
    Assert (pen_j == pen_k);
    Assert (pen_j == pen_m);

    buf = (unsigned char*)grib_handle_of_accessor(a)->buffer->data;

    maxv = pen_j+1;

    buf  += offsetdata;
    hres = buf;
    lres = buf;

    packed_offset = offsetdata +  bytes*(sub_k+1)*(sub_k+2);

    lpos = 8*(packed_offset-offsetdata);

    s = grib_power(binary_scale_factor,2);
    d = grib_power(-decimal_scale_factor,10) ;

    scals   = (double*)grib_context_malloc(a->context,maxv*sizeof(double));
    Assert(scals);

    scals[0] = 0;
    for(i=1;i<maxv;i++){
        operat = pow(i*(i+1),laplacianOperator);
        if(operat !=  0)
            scals[i] = (1.0/operat);
        else{
            scals[i] = 0;
        }
    }

    i=0;

    while(maxv>0)
    {
        lup=mmax;
        if(sub_k>=0)
        {
            for(hcount=0;hcount<sub_k+1;hcount++)
            {
                dummy =  decode_float(grib_decode_unsigned_long(hres,&hpos,8*bytes));
                dummy =  decode_float(grib_decode_unsigned_long(hres,&hpos,8*bytes));

                lup++;
            }
            sub_k--;
        }

        /* pscals=scals+lup; */
        for(lcount=hcount; lcount < maxv ; lcount++)
        {
            val[i++] = d * (double) ((grib_decode_unsigned_long(lres, &lpos,
                    bits_per_value)*s)+reference_value);
            val[i++] = d * (double) ((grib_decode_unsigned_long(lres, &lpos,
                    bits_per_value)*s)+reference_value);
            lup++;
        }

        maxv--;
        hcount=0;
        mmax++;
    }

    Assert(*len >= i);
    *len = n_vals;


    (void)dummy; /* suppress gcc warning */
    grib_context_free(a->context,scals);

    return ret;
}
