/* This is a plugin for GIMP.
 *
 * Copyright (C) 1997 Jochen Friedrich
 * Parts Copyright (C) 1995 Gert Doering
 * Parts Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "config.h"

#include <errno.h>
#include <string.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <sys/types.h>
#include <fcntl.h>

#include <glib.h>		/* For G_OS_WIN32 */
#include <glib/gstdio.h>

#ifdef G_OS_WIN32
#include <io.h>
#endif

#ifndef _O_BINARY
#define _O_BINARY 0
#endif

#include <libgimp/gimp.h>

#include "g3.h"

#include "libgimp/stdplugins-intl.h"


#define LOAD_PROC "file-faxg3-load"
#define VERSION   "0.6"

/* Declare local functions.
 */

static void   query      (void);
static void   run        (const gchar      *name,
			  gint              nparams,
			  const GimpParam  *param,
			  gint             *nreturn_vals,
			  GimpParam       **return_vals);

static gint32 load_image (const gchar      *filename,
                          GError          **error);

static gint32 emitgimp   (gint              hcol,
                          gint              row,
                          const gchar      *bitmap,
                          gint              bperrow,
                          const gchar      *filename);


const GimpPlugInInfo PLUG_IN_INFO =
{
  NULL,  /* init_proc  */
  NULL,  /* quit_proc  */
  query, /* query_proc */
  run,   /* run_proc   */
};

MAIN ()

void query (void)
{
  static const GimpParamDef load_args[] =
  {
    { GIMP_PDB_INT32,  "run-mode",     "The run mode { RUN-INTERACTIVE (0), RUN-NONINTERACTIVE (1) }" },
    { GIMP_PDB_STRING, "filename",     "The name of the file to load" },
    { GIMP_PDB_STRING, "raw-filename", "The name of the file to load" },
  };
  static const GimpParamDef load_return_vals[] =
  {
    { GIMP_PDB_IMAGE, "image", "Output image" },
  };

  gimp_install_procedure (LOAD_PROC,
                          "loads g3 fax files",
			  "This plug-in loads Fax G3 Image files.",
                          "Jochen Friedrich",
                          "Jochen Friedrich, Gert Doering, Spencer Kimball & Peter Mattis",
                          VERSION,
			  N_("G3 fax image"),
			  NULL,
                          GIMP_PLUGIN,
                          G_N_ELEMENTS (load_args),
                          G_N_ELEMENTS (load_return_vals),
                          load_args, load_return_vals);

  gimp_register_file_handler_mime (LOAD_PROC, "image/g3-fax");
  gimp_register_magic_load_handler (LOAD_PROC,
				    "g3",
				    "",
				    "4,string,Research");
}

static void
run (const gchar      *name,
     gint              nparams,
     const GimpParam  *param,
     gint             *nreturn_vals,
     GimpParam       **return_vals)
{
  static GimpParam  values[2];
  gint32            image_ID;
  GError           *error = NULL;

  *nreturn_vals = 1;
  *return_vals = values;

  values[0].type = GIMP_PDB_STATUS;
  values[0].data.d_status = GIMP_PDB_CALLING_ERROR;

  if (strcmp (name, LOAD_PROC) == 0)
    {
      INIT_I18N();

      image_ID = load_image (param[1].data.d_string, &error);

      if (image_ID != -1)
	{
          *nreturn_vals = 2;

	  values[0].data.d_status = GIMP_PDB_SUCCESS;
          values[1].type = GIMP_PDB_IMAGE;
          values[1].data.d_image = image_ID;
	}
      else
	{
	  values[0].data.d_status = GIMP_PDB_EXECUTION_ERROR;

          if (error)
            {
              *nreturn_vals = 2;
              values[1].type          = GIMP_PDB_STRING;
              values[1].data.d_string = error->message;
            }
        }
    }
}

#ifdef DEBUG
void putbin (unsigned long d )
{
unsigned long i = 0x80000000;

    while ( i!=0 )
    {
	putc( ( d & i ) ? '1' : '0', stderr );
	i >>= 1;
    }
    putc( '\n', stderr );
}
#endif

static int byte_tab[ 256 ];
/* static int o_stretch; */		/* -stretch: double each line */
/* static int o_stretch_force=-1; */	/* -1: guess from filename */
/* static int o_lj; */			/* -l: LJ output */
/* static int o_turn; */		/* -t: turn 90 degrees right */

struct g3_tree * black, * white;

#define CHUNK 2048;
static	char rbuf[2048];	/* read buffer */
static	int  rp;		/* read pointer */
static	int  rs;		/* read buffer size */

#define MAX_ROWS 4300
#define MAX_COLS 1728		/* !! FIXME - command line parameter */


static gint32
load_image (const gchar  *filename,
            GError      **error)
{
  int data;
  int hibit;
  struct g3_tree * p;
  int nr_pels;
  int fd;
  int color;
  int i, rr, rsize;
  int cons_eol;

  gint32 image_id;
  gint   bperrow = MAX_COLS/8;	/* bytes per bit row */
  gchar *bitmap;		/* MAX_ROWS by (bperrow) bytes */
  gchar *bp;			/* bitmap pointer */
  gint	 row;
  gint	 max_rows;		/* max. rows allocated */
  gint 	 col, hcol;		/* column, highest column ever used */

  gimp_progress_init_printf (_("Opening '%s'"),
                             gimp_filename_to_utf8 (filename));

  /* initialize lookup trees */
  build_tree( &white, t_white );
  build_tree( &white, m_white );
  build_tree( &black, t_black );
  build_tree( &black, m_black );

  init_byte_tab( 0, byte_tab );

  fd = g_open (filename, O_RDONLY | _O_BINARY, 0);

  if (fd < 0)
    {
      g_set_error (error, G_FILE_ERROR, g_file_error_from_errno (errno),
                   _("Could not open '%s' for reading: %s"),
                   gimp_filename_to_utf8 (filename), g_strerror (errno));
      return -1;
    }

  hibit = 0;
  data = 0;

  cons_eol = 0;	/* consecutive EOLs read - zero yet */

  color = 0;		/* start with white */
  rr = 0;

  rsize = lseek(fd, 0L, SEEK_END);
  lseek(fd, 0L, 0);

  rs = read( fd, rbuf, sizeof(rbuf) );
  if ( rs < 0 ) { perror( "read" ); close( rs ); gimp_quit (); }
  rr += rs;
  gimp_progress_update ((float)rr/rsize/2.0);

			/* skip GhostScript header */
  rp = ( rs >= 64 && strcmp( rbuf+1, "PC Research, Inc" ) == 0 ) ? 64 : 0;

  /* initialize bitmap */

  row = col = hcol = 0;

  bitmap = g_new0 (gchar, ( max_rows = MAX_ROWS ) * MAX_COLS / 8 );

  bp = &bitmap[ row * MAX_COLS/8 ];

  while ( rs > 0 && cons_eol < 4 )	/* i.e., while (!EOF) */
  {
#ifdef DEBUG
    g_printerr ("hibit=%2d, data=", hibit );
    putbin( data );
#endif
    while ( hibit < 20 )
    {
      data |= ( byte_tab[ (int) (unsigned char) rbuf[ rp++] ] << hibit );
      hibit += 8;

      if ( rp >= rs )
      {
        rs = read( fd, rbuf, sizeof( rbuf ) );
        if ( rs < 0 ) { perror( "read2"); break; }
        rr += rs;
        gimp_progress_update ((float)rr/rsize/2.0);
        rp = 0;
        if ( rs == 0 ) { goto do_write; }
      }
#ifdef DEBUG
      g_printerr ("hibit=%2d, data=", hibit );
      putbin( data );
#endif
    }

    if ( color == 0 )		/* white */
      p = white->nextb[ data & BITM ];
    else			/* black */
      p = black->nextb[ data & BITM ];

    while ( p != NULL && ! ( p->nr_bits ) )
    {
	    data >>= FBITS;
	    hibit -= FBITS;
	    p = p->nextb[ data & BITM ];
	}

	if ( p == NULL )	/* invalid code */
	{
	    g_printerr ("invalid code, row=%d, col=%d, file offset=%lx, skip to eol\n",
                        row, col, (unsigned long) lseek( fd, 0, 1 ) - rs + rp );
	    while ( ( data & 0x03f ) != 0 )
	    {
		data >>= 1; hibit--;
		if ( hibit < 20 )
		{
		    data |= ( byte_tab[ (int) (unsigned char) rbuf[ rp++] ] << hibit );
		    hibit += 8;

		    if ( rp >= rs )	/* buffer underrun */
		    {   rs = read( fd, rbuf, sizeof( rbuf ) );
			if ( rs < 0 ) { perror( "read4"); break; }
        		rr += rs;
      			gimp_progress_update ((float)rr/rsize/2.0);
			rp = 0;
			if ( rs == 0 ) goto do_write;
		    }
		}
	    }
	    nr_pels = -1;		/* handle as if eol */
	}
	else				/* p != NULL <-> valid code */
	{
	    data >>= p->nr_bits;
	    hibit -= p->nr_bits;

	    nr_pels = ( (struct g3_leaf *) p ) ->nr_pels;
#ifdef DEBUG
	    g_printerr ("PELs: %d (%c)\n", nr_pels, '0'+color );
#endif
	}

	/* handle EOL (including fill bits) */
	if ( nr_pels == -1 )
	{
#ifdef DEBUG
	    g_printerr ("hibit=%2d, data=", hibit );
	    putbin( data );
#endif
	    /* skip filler 0bits -> seek for "1"-bit */
	    while ( ( data & 0x01 ) != 1 )
	    {
		if ( ( data & 0xf ) == 0 )	/* nibble optimization */
		{
		    hibit-= 4; data >>= 4;
		}
		else
		{
		    hibit--; data >>= 1;
		}
		/* fill higher bits */
		if ( hibit < 20 )
		{
		    data |= ( byte_tab[ (int) (unsigned char) rbuf[ rp++] ] << hibit );
		    hibit += 8;

		    if ( rp >= rs )	/* buffer underrun */
		    {   rs = read( fd, rbuf, sizeof( rbuf ) );
			if ( rs < 0 ) { perror( "read3"); break; }
        		rr += rs;
      			gimp_progress_update ((float)rr/rsize/2.0);
			rp = 0;
			if ( rs == 0 ) goto do_write;
		    }
		}
#ifdef DEBUG
	    g_printerr ("hibit=%2d, data=", hibit );
	    putbin( data );
#endif
	    }				/* end skip 0bits */
	    hibit--; data >>=1;

	    color=0;

	    if ( col == 0 )
		cons_eol++;		/* consecutive EOLs */
	    else
	    {
	        if ( col > hcol && col <= MAX_COLS ) hcol = col;
		row++;

		/* bitmap memory full? make it larger! */
		if ( row >= max_rows )
                  {
                    gchar *p = g_try_realloc( bitmap,
                                              ( max_rows += 500 ) * MAX_COLS/8 );
		    if ( p == NULL )
                      {
			perror( "realloc() failed, page truncated" );
			rs = 0;
                      }
		    else
                      {
			bitmap = p;
			memset( &bitmap[ row * MAX_COLS/8 ], 0,
			       ( max_rows - row ) * MAX_COLS/8 );
                      }
                  }

		col=0; bp = &bitmap[ row * MAX_COLS/8 ];
		cons_eol = 0;
	    }
	}
	else		/* not eol */
	{
	    if ( col+nr_pels > MAX_COLS ) nr_pels = MAX_COLS - col;

	    if ( color == 0 )                  /* white */
		col += nr_pels;
	    else                               /* black */
	    {
            register int bit = ( 0x80 >> ( col & 07 ) );
	    register char *w = & bp[ col>>3 ];

		for ( i=nr_pels; i > 0; i-- )
		{
		    *w |= bit;
		    bit >>=1; if ( bit == 0 ) { bit = 0x80; w++; }
		    col++;
		}
	    }
	    if ( nr_pels < 64 ) color = !color;		/* terminating code */
	}
    }		/* end main loop */

do_write:      	/* write pbm (or whatever) file */

    if( fd != 0 ) close(fd);	/* close input file */

#ifdef DEBUG
    g_printerr ("consecutive EOLs: %d, max columns: %d\n", cons_eol, hcol );
#endif

    image_id = emitgimp (hcol, row, bitmap, bperrow, filename);

    g_free (bitmap);

    return image_id;
}

/* hcol is the number of columns, row the number of rows
 * bperrow is the number of bytes actually used by hcol, which may
 * be greater than (hcol+7)/8 [in case of an unscaled g3 image less
 * than 1728 pixels wide]
 */

static gint32
emitgimp (gint         hcol,
          gint         row,
          const gchar *bitmap,
          gint         bperrow,
          const gchar *filename)
{
  GimpPixelRgn  pixel_rgn;
  GimpDrawable *drawable;
  gint32        image_ID;
  gint32        layer_ID;
  guchar       *buf;
  guchar        tmp;
  gint          x,y,xx,yy,tile_height;

  /* initialize */

  tmp = 0;

#ifdef DEBUG
  g_printerr ("emit gimp: %d x %d\n", hcol, row);
#endif

  image_ID = gimp_image_new (hcol, row, GIMP_GRAY);
  gimp_image_set_filename (image_ID, filename);

  layer_ID = gimp_layer_new (image_ID, _("Background"),
			     hcol,
			     row,
			     GIMP_GRAY_IMAGE, 100, GIMP_NORMAL_MODE);
  gimp_image_insert_layer (image_ID, layer_ID, -1, 0);

  drawable = gimp_drawable_get (layer_ID);
  gimp_pixel_rgn_init (&pixel_rgn, drawable,
                       0, 0, drawable->width, drawable->height, TRUE, FALSE);
  tile_height = gimp_tile_height ();
#ifdef DEBUG
  g_printerr ("tile height: %d\n", tile_height);
#endif

  buf = g_new (guchar, hcol*tile_height);
  xx=0;
  yy=0;
  for (y=0; y<row; y++) {
    for (x=0; x<hcol; x++) {
      if ((x&7)==0) tmp = bitmap[y*bperrow+(x>>3)];
      buf[xx++]=tmp&(128>>(x&7))?0:255;
    }
    if ((y-yy) == tile_height-1) {
#ifdef DEBUG
      g_printerr ("update tile height: %d\n", tile_height);
#endif
      gimp_pixel_rgn_set_rect (&pixel_rgn, buf, 0, yy, hcol, tile_height);
      gimp_progress_update (0.5+(float)y/row/2.0);
      xx=0;
      yy += tile_height;
    }
  }
  if (row-yy) {
#ifdef DEBUG
    g_printerr ("update rest: %d\n", row-yy);
#endif
    gimp_pixel_rgn_set_rect (&pixel_rgn, buf, 0, yy, hcol, row-yy);
  }
  gimp_progress_update (1.0);

  g_free (buf);

  gimp_drawable_flush (drawable);

  return image_ID;
}