/**
* Copyright 2005-2007 ECMWF
*
* Licensed under the GNU Lesser General Public License which
* incorporates the terms and conditions of version 3 of the GNU
* General Public License.
* See LICENSE and gpl-3.0.txt for details.
*/

#include "grib_api_internal.h"
#define PNG_ANYBITS

/*
   This is used by make_class.pl

   START_CLASS_DEF
   CLASS      = accessor
   SUPER      = grib_accessor_class_values
   IMPLEMENTS = init
   IMPLEMENTS = unpack_double
   IMPLEMENTS = pack_double
   IMPLEMENTS = value_count
   MEMBERS=const char*   number_of_values
   MEMBERS=const char*   reference_value
   MEMBERS=const char*   binary_scale_factor
   MEMBERS=const char*   decimal_scale_factor
   MEMBERS=const char*   bits_per_value
   MEMBERS=const char*   ni
   MEMBERS=const char*   nj
   MEMBERS=const char*   list_defining_points
   MEMBERS=const char*   number_of_data_points
   MEMBERS=const char*   scanning_mode

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

typedef struct grib_accessor_data_png_packing {
    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_png_packing */
	const char*   number_of_values;
	const char*   reference_value;
	const char*   binary_scale_factor;
	const char*   decimal_scale_factor;
	const char*   bits_per_value;
	const char*   ni;
	const char*   nj;
	const char*   list_defining_points;
	const char*   number_of_data_points;
	const char*   scanning_mode;
} grib_accessor_data_png_packing;

extern grib_accessor_class* grib_accessor_class_values;

static grib_accessor_class _grib_accessor_class_data_png_packing = {
    &grib_accessor_class_values,                      /* super                     */
    "data_png_packing",                      /* name                      */
    sizeof(grib_accessor_data_png_packing),  /* size                      */
    0,                           /* inited */
    &init_class,                 /* init_class */
    &init,                       /* init                      */
    0,                  /* post_init                      */
    0,                    /* free mem                       */
    0,                       /* describes himself         */
    0,                /* get length of section     */
    &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    */
    &pack_double,                /* grib_pack procedures double    */
    &unpack_double,              /* grib_unpack procedures double  */
    0,                /* grib_pack procedures string    */
    0,              /* grib_unpack 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          */
};


grib_accessor_class* grib_accessor_class_data_png_packing = &_grib_accessor_class_data_png_packing;


static void init_class(grib_accessor_class* c)
{
	c->dump	=	(*(c->super))->dump;
	c->next_offset	=	(*(c->super))->next_offset;
	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_string	=	(*(c->super))->pack_string;
	c->unpack_string	=	(*(c->super))->unpack_string;
	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;
}

/* END_CLASS_IMP */

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

  self->number_of_values      = grib_arguments_get_name(a->parent->h,args,self->carg++);
  self->reference_value       = grib_arguments_get_name(a->parent->h,args,self->carg++);
  self->binary_scale_factor   = grib_arguments_get_name(a->parent->h,args,self->carg++);
  self->decimal_scale_factor  = grib_arguments_get_name(a->parent->h,args,self->carg++);
  self->bits_per_value           = grib_arguments_get_name(a->parent->h,args,self->carg++);

  self->ni                     = grib_arguments_get_name(a->parent->h,args,self->carg++);
  self->nj                     = grib_arguments_get_name(a->parent->h,args,self->carg++);

  self->list_defining_points   = grib_arguments_get_name(a->parent->h,args,self->carg++);
  self->number_of_data_points  = grib_arguments_get_name(a->parent->h,args,self->carg++);
  self->scanning_mode      = grib_arguments_get_name(a->parent->h,args,self->carg++);
  a->flags |= GRIB_ACCESSOR_FLAG_DATA;

}

static long value_count(grib_accessor* a)
{
  grib_accessor_data_png_packing *self =(grib_accessor_data_png_packing*)a;
  long n_vals= 0;
  if(grib_get_long_internal(a->parent->h,self->number_of_values,&n_vals) != GRIB_SUCCESS)
    return 0;

  return n_vals;
}

#if HAVE_LIBPNG

#include "png.h"

typedef struct png_read_callback_data {
  unsigned char* buffer;
  size_t         length;
  size_t         offset;
} png_read_callback_data;

static void png_read_callback(png_structp png,png_bytep data, png_size_t length)
{
  png_read_callback_data* p = (png_read_callback_data*)png_get_io_ptr(png);
  Assert(p->offset + length <= p->length);
  memcpy(data,p->buffer+p->offset,length);
  p->offset += length;
}

static void png_write_callback(png_structp png,png_bytep data, png_size_t length)
{
  png_read_callback_data* p = (png_read_callback_data*)png_get_io_ptr(png);
  Assert(p->offset + length <= p->length);
  memcpy(p->buffer+p->offset,data,length);
  p->offset += length;
}

static void png_flush_callback(png_structp png)
{
  /* Empty */
}


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

  int err = GRIB_SUCCESS;
  int i,j;
  size_t buflen = grib_byte_count(a);

  double bscale = 0;
  double dscale = 0;
  unsigned char* buf = NULL;
  size_t n_vals = 0;

  long binary_scale_factor = 0;
  long decimal_scale_factor = 0;
  double reference_value = 0;
  long bits_per_value =0;
  long bits8;

  png_structp png  = 0;
  png_infop info = 0,end = 0;
  png_bytepp rows = 0;
  int interlace = 0,colour = 0,compression = 0,filter = 0,depth = 0;

  png_uint_32 width = 0,height = 0;

  png_read_callback_data callback_data;

  self->dirty=0;

  n_vals = grib_value_count(a);

  if((err = grib_get_long_internal(a->parent->h,self->bits_per_value,&bits_per_value)) != GRIB_SUCCESS)
    return err;
  if((err = grib_get_double_internal(a->parent->h,self->reference_value, &reference_value)) != GRIB_SUCCESS)
    return err;
  if((err = grib_get_long_internal(a->parent->h,self->binary_scale_factor, &binary_scale_factor)) != GRIB_SUCCESS)
    return err;
  if((err = grib_get_long_internal(a->parent->h,self->decimal_scale_factor, &decimal_scale_factor)) != GRIB_SUCCESS)
    return err;

  bscale = grib_power(binary_scale_factor,2);
  dscale = grib_power(-decimal_scale_factor,10);

  /* TODO: This should be called upstream */
  if(*len < n_vals)
    return GRIB_ARRAY_TOO_SMALL;

  /* Special case */

  if(bits_per_value == 0)
  {
    for(i = 0; i < n_vals; i++)
      val[i] = reference_value;
    *len = n_vals;
    return GRIB_SUCCESS;
  }

  buf = (unsigned char*)a->parent->h->buffer->data;
  buf += grib_byte_offset(a);


  if ( png_sig_cmp(buf,0,8) != 0)
    return GRIB_INVALID_MESSAGE;


  png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
      NULL, NULL);
  if (!png)
  {
    err = GRIB_DECODING_ERROR;
    goto cleanup;
  }

  info = png_create_info_struct(png);
  if (!info)
  {
    err = GRIB_DECODING_ERROR;
    goto cleanup;
  }

  end = png_create_info_struct(png);
  if (!end)
  {
    err = GRIB_DECODING_ERROR;
    goto cleanup;
  }

  if (setjmp(png_jmpbuf(png)))
  {
    err = GRIB_DECODING_ERROR;
    goto cleanup;
  }

  callback_data.buffer = buf;
  callback_data.offset = 0;
  callback_data.length = buflen;

  /* printf("buflen=%d\n",buflen); */

  png_set_read_fn(png,&callback_data,png_read_callback);
  png_read_png(png, info, PNG_TRANSFORM_IDENTITY, NULL);

  Assert(callback_data.offset == callback_data.length);


  rows = png_get_rows(png, info);

  png_get_IHDR(png, info,
      &width, &height,
      &depth, &colour,
      &interlace,
      &compression,
      &filter);


  if (colour == PNG_COLOR_TYPE_RGB)      depth=24;
  if (colour == PNG_COLOR_TYPE_RGB_ALPHA) depth=32;
  bits8 = ((bits_per_value+7)/8)*8;

#ifdef PNG_ANYBITS
  Assert(depth == bits8);
#else
  Assert( bits_per_value % 8 == 0 );
#endif

  i = 0;

  /* printf("bscale=%g dscale=%g reference_value=%g\n",bscale,dscale,reference_value); */

  for(j=0; j<height;j++)
  {
    png_byte* row = rows[j];
    long pos = 0;
    int k;
    for(k = 0 ; k < width; k++)
      val[i++] = (double) (((grib_decode_unsigned_long(row, &pos, bits8)*bscale)+reference_value)*dscale);
  }
  /*-------------------------------------------*/
  *len = n_vals;


cleanup:
  if(png)
    png_destroy_read_struct(&png, info?&info:NULL, end?&end:NULL);
  return err;

}

static int pack_double(grib_accessor* a, const double* val, size_t *len)
{
  grib_accessor_data_png_packing *self =(grib_accessor_data_png_packing*)a;

  int err = GRIB_SUCCESS;
  int i,j;
  size_t buflen = grib_byte_count(a);

  unsigned char* buf = NULL;
  unsigned char* encoded = NULL;
  size_t n_vals = 0;

  long binary_scale_factor = 0;
  long decimal_scale_factor = 0;
  double reference_value = 0;
  long bits8;
  long bits_per_value =0;
  double max,min;
  long bytes;
  double d;

  png_structp png  = 0;
  png_infop info = 0;
  png_bytepp rows = 0;
  int colour = 0,depth = 0;

  png_uint_32 width = 0,height = 0;
  unsigned char *p;
  double divisor;

  png_read_callback_data callback_data;
  long ni,nj;
  long scanning_mode;
  long list_defining_points;
  long number_of_data_points;


  self->dirty=1;

  n_vals = grib_value_count(a);

  if((err = grib_get_long_internal(a->parent->h,self->bits_per_value,&bits_per_value)) != GRIB_SUCCESS)
    return err;
  if((err = grib_get_double_internal(a->parent->h,self->reference_value, &reference_value)) != GRIB_SUCCESS)
    return err;
  if((err = grib_get_long_internal(a->parent->h,self->binary_scale_factor, &binary_scale_factor)) != GRIB_SUCCESS)
    return err;
  if((err = grib_get_long_internal(a->parent->h,self->decimal_scale_factor, &decimal_scale_factor)) != GRIB_SUCCESS)
    return err;

  /* Special case */

  if(*len == 0) {
    grib_buffer_replace(a, NULL, 0,1,1);
    return GRIB_SUCCESS;
  }

  if(bits_per_value == 0)
  {
    int i;
    /* constant field */
    for(i = 1 ; i < n_vals; i++)
      Assert(val[i] == val[0]);

    if((err = grib_set_double_internal(a->parent->h,self->reference_value, val[0])) != GRIB_SUCCESS)
      return err;
    {
      /* Make sure we can decode it again */
      double ref = 1e-100;
      grib_get_double_internal(a->parent->h,self->reference_value,&ref);
	  printf("%g %g %g\n",reference_value,ref,reference_value-ref);
      Assert(ref == reference_value);
    }

    if((err = grib_set_long_internal(a->parent->h,self->number_of_values, n_vals)) !=  GRIB_SUCCESS)
      return err;

    grib_buffer_replace(a, NULL, 0,1,1);

    return GRIB_SUCCESS;
  }

  if((err = grib_get_long_internal(a->parent->h,self->ni,&ni)) != GRIB_SUCCESS)
    return err;

  if((err = grib_get_long_internal(a->parent->h,self->nj,&nj)) != GRIB_SUCCESS)
    return err;

  if((err = grib_get_long_internal(a->parent->h,self->scanning_mode,&scanning_mode)) != GRIB_SUCCESS)
    return err;

  if((err = grib_get_long_internal(a->parent->h,self->list_defining_points,&list_defining_points)) != GRIB_SUCCESS)
    return err;

  if((err = grib_get_long_internal(a->parent->h,self->number_of_data_points,&number_of_data_points)) != GRIB_SUCCESS)
    return err;

  width  = ni;
  height = nj;

  if((scanning_mode & (1<<5)) != 0)
  {
    long tmp = width;
    width    = height;
    height   = tmp;
  }

  /* The grid is not regular */
  if(list_defining_points != 0)
  {
    width  = *len;
    height = 1;
  }

  /* There is a bitmap */
  if(*len != number_of_data_points)
  {
    width  = *len;
    height = 1;
  }


  if(width*height != *len)
  {
    fprintf(stderr,"width=%ld height=%ld len=%d\n",width,height,*len);
    Assert(width*height == *len);
  }


  d = grib_power(decimal_scale_factor,10) ;


  max = val[0];
  min = max;
  for(i=1;i< n_vals;i++)
  {
    if (val[i] > max )
      max = val[i];
    if (val[i] < min )
      min = val[i];
  }
  min *= d;
  max *= d;

  if (grib_get_nearest_smaller_value(a->parent->h,self->reference_value,min,&reference_value)
        !=GRIB_SUCCESS) {
        grib_context_log(a->parent->h->context,GRIB_LOG_ERROR,
         "unable to find nearest_smaller_value of %g for %s",min,self->reference_value);
        exit(GRIB_INTERNAL_ERROR);
  }

  if(reference_value > min)
  {
    fprintf(stderr,"reference_value=%g min_value=%g diff=%g\n",reference_value,min,reference_value-min);
    Assert(reference_value <= min);
  }

  binary_scale_factor = grib_get_binary_scale_fact(max,reference_value,bits_per_value,&err);
  divisor = grib_power(-binary_scale_factor,2);

#ifndef PNG_ANYBITS
  Assert(bits_per_value % 8 == 0);
#endif
  bits8 = (bits_per_value+7)/8*8;
  encoded = grib_context_buffer_malloc_clear(a->parent->h->context,bits8/8*n_vals);

  if(!encoded) {
    err = GRIB_OUT_OF_MEMORY;
    goto cleanup;
  }

  buflen = 0;
  p = encoded;
  for(i=0;i< n_vals;i++){
    long blen = bits8;
    unsigned long unsigned_val = (unsigned long)((((val[i]*d)-(reference_value))*divisor)+0.5);
    while(blen >= 8)
    {
      blen   -= 8;
      *p = (unsigned_val >> blen);
      p++;
      buflen++;
    }
  }
  /*       buflen = n_vals*(bits_per_value/8);*/

  grib_context_log(a->parent->h->context, GRIB_LOG_DEBUG,
      "grib_accessor_data_png_packing : pack_double : packing %s, %d values", a->name, n_vals);
  buf = grib_context_buffer_malloc_clear(a->parent->h->context,buflen);

  if(!buf) {
    err = GRIB_OUT_OF_MEMORY;
    goto cleanup;
  }


  if((err = grib_set_double_internal(a->parent->h,self->reference_value, reference_value)) != GRIB_SUCCESS)
    return err;
  {
    /* Make sure we can decode it again */
    double ref = 1e-100;
    grib_get_double_internal(a->parent->h,self->reference_value,&ref);
    Assert(ref == reference_value);
  }
  if((err = grib_set_long_internal(a->parent->h,self->binary_scale_factor, binary_scale_factor)) != GRIB_SUCCESS)
    return err;
  if((err = grib_set_long_internal(a->parent->h,self->decimal_scale_factor, decimal_scale_factor)) != GRIB_SUCCESS)
    return err;

  if((err = grib_get_long_internal(a->parent->h,self->ni,&ni)) != GRIB_SUCCESS)
    return err;

  if((err = grib_get_long_internal(a->parent->h,self->nj,&nj)) != GRIB_SUCCESS)
    return err;

  png = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
  if (!png)
  {
    err = GRIB_DECODING_ERROR;
    goto cleanup;
  }

  info = png_create_info_struct(png);
  if (!info)
  {
    err = GRIB_DECODING_ERROR;
    goto cleanup;
  }

  if (setjmp(png_jmpbuf(png)))
  {
    err = GRIB_DECODING_ERROR;
    goto cleanup;
  }


  callback_data.buffer = buf;
  callback_data.offset = 0;
  callback_data.length = buflen;

  /* printf("buflen=%d\n",buflen); */


  png_set_write_fn(png,&callback_data,png_write_callback,png_flush_callback);

  depth = bits8;

  colour = PNG_COLOR_TYPE_GRAY;
  if (bits8 == 24)
  {
    depth=8;
    colour=PNG_COLOR_TYPE_RGB;
  }

  if(bits8 == 32 )
  {
    depth=8;
    colour=PNG_COLOR_TYPE_RGB_ALPHA;
  }

  png_set_IHDR(png, info, width, height,
      depth, colour, PNG_INTERLACE_NONE,
      PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);


  /*bytes=bit_depth/8;*/
  bytes = bits8/8;

  rows = grib_context_buffer_malloc_clear(a->parent->h->context,sizeof(png_bytep)*height);

  rows  = malloc(height*sizeof(png_bytep));
  for (j=0;j<height;j++)
    rows[j] = &encoded[j*width*bytes];

  png_set_rows(png, info,rows);

  png_write_png(png, info, PNG_TRANSFORM_IDENTITY, NULL);

  Assert(callback_data.offset <= callback_data.length);


  grib_buffer_replace(a, buf, callback_data.offset,1,1);

cleanup:
  if(png)
    png_destroy_write_struct(&png, info?&info:NULL);


  grib_context_buffer_free(a->parent->h->context,buf);
  grib_context_buffer_free(a->parent->h->context,encoded);
  grib_context_buffer_free(a->parent->h->context,rows);

  if(err == GRIB_SUCCESS)
    err = grib_set_long_internal(a->parent->h,self->number_of_values, *len);

  return err;
}
#else

static int  unpack_double(grib_accessor* a, double* val, size_t *len)
{
  grib_context_log(a->parent->h->context, GRIB_LOG_ERROR,
      "grib_accessor_data_png_packing : png support no enabled. Please rerun configure with --with-png-support");
  return GRIB_NOT_IMPLEMENTED;
}

static int pack_double(grib_accessor* a, const double* val, size_t *len)
{
  grib_context_log(a->parent->h->context, GRIB_LOG_ERROR,
      "grib_accessor_data_png_packing : png support no enabled. Please rerun configure with --with-png-support");
  return GRIB_NOT_IMPLEMENTED;
}

#endif
