/*
 * 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"
/*
   This is used by make_class.pl

   START_CLASS_DEF
   CLASS      = accessor
   SUPER      = grib_accessor_class_section_length
   IMPLEMENTS = init;unpack_long;pack_long
   MEMBERS    = const char *sec4_length
   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 pack_long(grib_accessor*, const long* val,size_t *len);
static int unpack_long(grib_accessor*, long* val,size_t *len);
static void init(grib_accessor*,const long, grib_arguments* );
static void init_class(grib_accessor_class*);

typedef struct grib_accessor_g1_message_length {
    grib_accessor          att;
/* Members defined in gen */
/* Members defined in long */
/* Members defined in unsigned */
	long nbytes;
	grib_arguments* arg;
/* Members defined in section_length */
/* Members defined in g1_message_length */
	const char *sec4_length;
} grib_accessor_g1_message_length;

extern grib_accessor_class* grib_accessor_class_section_length;

static grib_accessor_class _grib_accessor_class_g1_message_length = {
    &grib_accessor_class_section_length,                      /* super                     */
    "g1_message_length",                      /* name                      */
    sizeof(grib_accessor_g1_message_length),  /* 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      */
    0,                /* 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      */
    &pack_long,                  /* grib_pack procedures long      */
    &unpack_long,                /* grib_unpack procedures long    */
    0,                /* grib_pack procedures double    */
    0,              /* 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_g1_message_length = &_grib_accessor_class_g1_message_length;


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->value_count	=	(*(c->super))->value_count;
	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_double	=	(*(c->super))->pack_double;
	c->unpack_double	=	(*(c->super))->unpack_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 void init(grib_accessor* a, const long len , grib_arguments* args )
{
    grib_accessor_g1_message_length *self = (grib_accessor_g1_message_length*)a;
  self->sec4_length           = grib_arguments_get_name(grib_handle_of_accessor(a),args,0);
}

int grib_get_g1_message_size(grib_handle* h,grib_accessor* tl,grib_accessor* s4,
  long* total_length,long* sec4_len)
{
  unsigned long tlen,slen;
  long off;

  if(!tl) return GRIB_NOT_FOUND;
  if(!s4) {
     *sec4_len     = 0;
     off = tl->offset * 8;
     *total_length = grib_decode_unsigned_long(h->buffer->data, &off, tl->length * 8);
     return GRIB_SUCCESS;
   }

  off = tl->offset * 8;
  tlen = grib_decode_unsigned_long(h->buffer->data, &off, tl->length * 8);

  off = s4->offset * 8;
  slen = grib_decode_unsigned_long(h->buffer->data, &off, s4->length * 8);

  /* printf("\nlarge grib tlen=%ld slen=%ld diff=%ld\n",tlen&0x7fffff,slen,tlen-slen); */

  if(slen < 120 && (tlen & 0x800000))
  {
    /* printf("DECODING large grib tlen=%ld slen=%ld\n",tlen,slen); */

    tlen &= 0x7fffff;
    tlen *= 120;
    tlen -= slen;
    tlen += 4;

    slen = tlen - s4->offset - 4; /* 4 is for 7777 */;

    /*printf("DECODING large grib total=%ld section4=%ld\n",tlen,slen);*/
  }

  *total_length = tlen;
  *sec4_len     = slen;

  return GRIB_SUCCESS;
}

static int pack_long(grib_accessor* a, const long* val,size_t *len)
{
  grib_accessor_g1_message_length *self = (grib_accessor_g1_message_length*)a;
  /*grib_accessor_class* super = *(a->cclass->super);*/

  /* Here we assume that the totalLength will be coded AFTER the section4 length, and
  the section4 length will be overwritten by the totalLength accessor for large GRIBs */

  grib_accessor* s4 = grib_find_accessor(grib_handle_of_accessor(a),self->sec4_length);
  long tlen,slen;
  long t120;
  int ret;

  tlen = *val;
  if((tlen < 0x800000 || !a->context->gribex_mode_on) && tlen < 0xFFFFFF  )
  {
    /* printf("ENCODING small grib total = %ld\n",tlen); */
    /*return super->pack_long(a,val,len);*/

    /* Do not directly call pack_long on base class */
    /* because in this special case we want to skip the checks. */
    /* So we call the helper function which has an extra argument */
    return pack_long_unsigned_helper(a,val,len, /*check=*/0);
  }

  if(!s4) return GRIB_NOT_FOUND;

  /* special case for large GRIBs */
  tlen -= 4;
  t120  = (tlen+119)/120;
  slen  = t120*120 - tlen;
  tlen  = 0x800000 | t120;

  /* printf("ENCODING large grib total = %ld tlen=%ld slen=%ld \n",*val,tlen,slen);  */
  *len = 1;
  if((ret = grib_pack_long(s4,&slen,len)) != GRIB_SUCCESS)
    return ret;

  *len = 1;
  /* Do not do the length checks in this special case */
  if((ret = pack_long_unsigned_helper(a,&tlen,len,/*check=*/0)) != GRIB_SUCCESS)
      return ret;
  /*
  if((ret = super->pack_long(a,&tlen,len)) != GRIB_SUCCESS)
    return ret;
  */

  {
      long total_length = -1, sec4_length = -1;
      grib_get_g1_message_size(grib_handle_of_accessor(a),
        a,
        grib_find_accessor(grib_handle_of_accessor(a),self->sec4_length),
        &total_length,
        &sec4_length);

      Assert(total_length == *val);
  }

  return GRIB_SUCCESS;
}

static int unpack_long(grib_accessor* a, long* val,size_t *len)
{
  grib_accessor_g1_message_length *self = (grib_accessor_g1_message_length*)a;
  int ret;

  long total_length, sec4_length;

  if((ret = grib_get_g1_message_size(grib_handle_of_accessor(a),
    a,
    grib_find_accessor(grib_handle_of_accessor(a),self->sec4_length),
    &total_length,
    &sec4_length)) != GRIB_SUCCESS)
      return ret;


  *val = total_length;
  return GRIB_SUCCESS;
}
