/* The GIMP -- an image manipulation program
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "config.h"

#include <gtk/gtk.h>

#include "core/core-types.h"

#include "base/pixel-region.h"
#include "base/tile-manager.h"
#include "base/tile.h"

#include "paint-funcs/paint-funcs.h"

#include "core/gimpdrawable.h"
#include "core/gimpimage.h"

#include "gdisplay.h"
#include "image_map.h"


typedef enum
{
  IMAGE_MAP_WAITING,
  IMAGE_MAP_WORKING
} ImageMapState;


struct _ImageMap
{
  GDisplay            *gdisp;
  GimpDrawable        *drawable;
  TileManager         *undo_tiles;
  ImageMapApplyFunc    apply_func;
  gpointer             user_data;
  PixelRegion          srcPR;
  PixelRegion          destPR;
  PixelRegionIterator *PRI;
  ImageMapState        state;
  guint                idle_id;
};


/*  local function prototypes  */

static gboolean   image_map_do (gpointer data);


/*  public functions  */

ImageMap *
image_map_create (GDisplay     *gdisp,
		  GimpDrawable *drawable)
{
  ImageMap *image_map;

  g_return_val_if_fail (gdisp != NULL, NULL);
  g_return_val_if_fail (GIMP_IS_DRAWABLE (drawable), NULL);

  image_map = g_new0 (ImageMap, 1);

  image_map->gdisp      = gdisp;
  image_map->drawable   = drawable;
  image_map->undo_tiles = NULL;
  image_map->apply_func = NULL;
  image_map->user_data  = NULL;
  image_map->state      = IMAGE_MAP_WAITING;
  image_map->idle_id    = 0;

  /* Interactive tools based on image_map disable the undo stack
   * to avert any unintented undo interaction through the UI
   */
  gimp_image_undo_freeze (image_map->gdisp->gimage);
  gdisplay_set_menu_sensitivity (image_map->gdisp);

  return image_map;
}

void
image_map_apply (ImageMap          *image_map,
		 ImageMapApplyFunc  apply_func,
		 gpointer           apply_data)
{
  gint x1, y1;
  gint x2, y2;
  gint offset_x, offset_y;
  gint width, height;

  g_return_if_fail (image_map != NULL);
  g_return_if_fail (apply_func != NULL);

  image_map->apply_func = apply_func;
  image_map->user_data  = apply_data;

  /*  If we're still working, remove the timer  */
  if (image_map->state == IMAGE_MAP_WORKING)
    {
      g_source_remove (image_map->idle_id);
      image_map->idle_id = 0;

      pixel_regions_process_stop (image_map->PRI);
      image_map->PRI = NULL;
    }

  /*  Make sure the drawable is still valid  */
  if (! gimp_drawable_gimage (image_map->drawable))
    return;

  /*  The application should occur only within selection bounds  */
  gimp_drawable_mask_bounds (image_map->drawable, &x1, &y1, &x2, &y2);

  /*  If undo tiles don't exist, or change size, (re)allocate  */
  if (image_map->undo_tiles)
    {
      tile_manager_get_offsets (image_map->undo_tiles, &offset_x, &offset_y);
      width  = tile_manager_width (image_map->undo_tiles);
      height = tile_manager_height (image_map->undo_tiles);
    }
  else
    {
      offset_x = offset_y = width = height = 0;
    }

  if (! image_map->undo_tiles ||
      offset_x != x1 || offset_y != y1 ||
      width != (x2 - x1) || height != (y2 - y1))
    {
      /* If either the extents changed or the tiles don't exist,
       * allocate new
       */
      if (! image_map->undo_tiles ||
	  width != (x2 - x1) || height != (y2 - y1))
	{
	  /*  Destroy old tiles--If they exist  */
	  if (image_map->undo_tiles != NULL)
	    tile_manager_destroy (image_map->undo_tiles);

	  /*  Allocate new tiles  */
	  image_map->undo_tiles =
	    tile_manager_new ((x2 - x1), (y2 - y1),
			      gimp_drawable_bytes (image_map->drawable));
	}

      /*  Copy from the image to the new tiles  */
      pixel_region_init (&image_map->srcPR,
			 gimp_drawable_data (image_map->drawable),
			 x1, y1, (x2 - x1), (y2 - y1), FALSE);
      pixel_region_init (&image_map->destPR, image_map->undo_tiles,
			 0, 0, (x2 - x1), (y2 - y1), TRUE);

      copy_region (&image_map->srcPR, &image_map->destPR);

      /*  Set the offsets  */
      tile_manager_set_offsets (image_map->undo_tiles, x1, y1);
    }
  else /* image_map->undo_tiles exist AND drawable dimensions have not changed... */
    {
      /* Reset to initial drawable conditions.            */
      /* Copy from the backup undo tiles to the drawable  */
      pixel_region_init (&image_map->srcPR, image_map->undo_tiles, 
			 0, 0, width, height, FALSE);
      pixel_region_init (&image_map->destPR,
			 gimp_drawable_data (image_map->drawable), 
			 offset_x, offset_y, width, height, TRUE);

      copy_region (&image_map->srcPR, &image_map->destPR);
    }

  /*  Configure the src from the drawable data  */
  pixel_region_init (&image_map->srcPR, image_map->undo_tiles,
		     0, 0, (x2 - x1), (y2 - y1), FALSE);

  /*  Configure the dest as the shadow buffer  */
  pixel_region_init (&image_map->destPR,
		     gimp_drawable_shadow (image_map->drawable),
		     x1, y1, (x2 - x1), (y2 - y1), TRUE);

  /*  Apply the image transformation to the pixels  */
  image_map->PRI = pixel_regions_register (2,
					   &image_map->srcPR,
					   &image_map->destPR);

  /*  Start the intermittant work procedure  */
  image_map->state   = IMAGE_MAP_WORKING;
  image_map->idle_id = g_idle_add (image_map_do, image_map);
}

void
image_map_commit (ImageMap *image_map)
{
  gint x1, y1, x2, y2;

  g_return_if_fail (image_map != NULL);

  if (image_map->state == IMAGE_MAP_WORKING)
    {
      g_source_remove (image_map->idle_id);
      image_map->idle_id = 0;

      /*  Finish the changes  */
      while (image_map_do (image_map));
    }

  /*  Make sure the drawable is still valid  */
  if (! gimp_drawable_gimage (image_map->drawable))
    return;

  /* Interactive phase ends: we can commit an undo frame now */
  gimp_image_undo_thaw(image_map->gdisp->gimage);

  /*  Register an undo step  */
  if (image_map->undo_tiles)
    {
      tile_manager_get_offsets (image_map->undo_tiles, &x1, &y1);
      x2 = x1 + tile_manager_width (image_map->undo_tiles);
      y2 = y1 + tile_manager_height (image_map->undo_tiles);

      gimp_drawable_apply_image (image_map->drawable,
				 x1, y1, x2, y2, image_map->undo_tiles, FALSE);
    }

  gdisplay_set_menu_sensitivity (image_map->gdisp);
  g_free (image_map);
}

void
image_map_clear (ImageMap *image_map)
{
  PixelRegion srcPR, destPR;

  g_return_if_fail (image_map != NULL);

  if (image_map->state == IMAGE_MAP_WORKING)
    {
      g_source_remove (image_map->idle_id);
      image_map->idle_id = 0;

      pixel_regions_process_stop (image_map->PRI);
      image_map->PRI = NULL;
    }

  image_map->state = IMAGE_MAP_WAITING;

  /*  Make sure the drawable is still valid  */
  if (! gimp_drawable_gimage (image_map->drawable))
    return;

  /*  restore the original image  */
  if (image_map->undo_tiles)
    {
      gint offset_x;
      gint offset_y;
      gint width;
      gint height;

      tile_manager_get_offsets (image_map->undo_tiles, &offset_x, &offset_y);
      width  = tile_manager_width (image_map->undo_tiles);
      height = tile_manager_height (image_map->undo_tiles),

      /*  Copy from the drawable to the tiles  */
      pixel_region_init (&srcPR, image_map->undo_tiles, 
			 0, 0, width, height, FALSE);
      pixel_region_init (&destPR,
			 gimp_drawable_data (image_map->drawable),
			 offset_x, offset_y, width, height, TRUE);

      /* if the user has changed the image depth get out quickly */
      if (destPR.bytes != srcPR.bytes) 
	{
	  g_message ("image depth change, unable to restore original image");
	  tile_manager_destroy (image_map->undo_tiles);
          gimp_image_undo_thaw (image_map->gdisp->gimage);
          gdisplay_set_menu_sensitivity (image_map->gdisp);
	  g_free (image_map);
	  return;
	}

      copy_region (&srcPR, &destPR);

      /*  Update the area  */
      gimp_drawable_update (image_map->drawable,
			    offset_x, offset_y,
			    width, height);

      /*  Free the undo_tiles tile manager  */
      tile_manager_destroy (image_map->undo_tiles);
      image_map->undo_tiles = NULL;
    }
}

void
image_map_abort (ImageMap *image_map)
{
  g_return_if_fail (image_map != NULL);

  image_map_clear (image_map);
  gimp_image_undo_thaw (image_map->gdisp->gimage);
  gdisplay_set_menu_sensitivity (image_map->gdisp);
  g_free (image_map);
}

guchar *
image_map_get_color_at (ImageMap *image_map, 
			gint      x, 
			gint      y)
{
  Tile      *tile;
  guchar    *src;
  guchar    *dest;

  g_return_val_if_fail (image_map != NULL, NULL);

  if (x >= 0 && x < gimp_drawable_width (image_map->drawable) && 
      y >= 0 && y < gimp_drawable_height (image_map->drawable))
    {
      /* Check if done damage to original image */
      if (! image_map->undo_tiles)
	return (gimp_drawable_get_color_at (image_map->drawable, x, y));

      if (! image_map ||
	  (! gimp_drawable_gimage (image_map->drawable) && 
	   gimp_drawable_is_indexed (image_map->drawable)) ||
	  x < 0 || y < 0                                   ||
	  x >= tile_manager_width (image_map->undo_tiles)  ||
	  y >= tile_manager_height (image_map->undo_tiles))
	{
	  return NULL;
	}

      dest = g_new (guchar, 5);

      tile = tile_manager_get_tile (image_map->undo_tiles, x, y,
				    TRUE, FALSE);

      src = tile_data_pointer (tile, x % TILE_WIDTH, y % TILE_HEIGHT);

      gimp_image_get_color (gimp_drawable_gimage (image_map->drawable),
			    gimp_drawable_type (image_map->drawable),
			    dest, src);

      if (GIMP_IMAGE_TYPE_HAS_ALPHA (gimp_drawable_type (image_map->drawable)))
	dest[3] = src[gimp_drawable_bytes (image_map->drawable) - 1];
      else
	dest[3] = 255;

      if (gimp_drawable_is_indexed (image_map->drawable))
	dest[4] = src[0];
      else
	dest[4] = 0;

      tile_release (tile, FALSE);

      return dest;
    }
  else /* out of bounds error */
    {
      return NULL;
    }
}


/*  private functions  */

static gboolean
image_map_do (gpointer data)
{
  ImageMap    *image_map;
  GimpImage   *gimage;
  PixelRegion  shadowPR;
  gint         x, y, w, h;

  image_map = (ImageMap *) data;

  if (! (gimage = gimp_drawable_gimage (image_map->drawable)))
    {
      image_map->state = IMAGE_MAP_WAITING;

      return FALSE;
    }

  /*  Process the pixel regions and apply the image mapping  */
  (* image_map->apply_func) (&image_map->srcPR,
			     &image_map->destPR,
			     image_map->user_data);

  x = image_map->destPR.x;
  y = image_map->destPR.y;
  w = image_map->destPR.w;
  h = image_map->destPR.h;

  /*  apply the results  */
  pixel_region_init (&shadowPR, gimage->shadow, x, y, w, h, FALSE);
  gimp_image_apply_image (gimage, image_map->drawable, &shadowPR,
			  FALSE, OPAQUE_OPACITY, REPLACE_MODE, NULL, x, y);

  /*  display the results  */
  if (image_map->gdisp)
    {
      gimp_drawable_update (image_map->drawable,
			    x, y,
			    w, h);
      gdisplay_flush_now (image_map->gdisp);
    }

  image_map->PRI = pixel_regions_process (image_map->PRI);

  if (image_map->PRI == NULL)
    {
      image_map->state = IMAGE_MAP_WAITING;
      gdisplays_flush ();

      return FALSE;
    }

  return TRUE;
}