/* GIMP - The GNU 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 <gegl.h>

#include "libgimpcolor/gimpcolor.h"

#include "core-types.h"

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

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

#include "gimpimage.h"
#include "gimpimage-colormap.h"
#include "gimplayer.h"
#include "gimplayer-floating-sel.h"
#include "gimplayermask.h"
#include "gimppickable.h"
#include "gimpprojectable.h"
#include "gimpprojection.h"
#include "gimpprojection-construct.h"


/*  local function prototypes  */

static void   gimp_projection_construct_gegl     (GimpProjection *proj,
                                                  gint            x,
                                                  gint            y,
                                                  gint            w,
                                                  gint            h);
static void   gimp_projection_construct_layers   (GimpProjection *proj,
                                                  gint            x,
                                                  gint            y,
                                                  gint            w,
                                                  gint            h);
static void   gimp_projection_construct_channels (GimpProjection *proj,
                                                  gint            x,
                                                  gint            y,
                                                  gint            w,
                                                  gint            h);
static void   gimp_projection_initialize         (GimpProjection *proj,
                                                  gint            x,
                                                  gint            y,
                                                  gint            w,
                                                  gint            h);

static void   project_intensity                  (GimpProjection *proj,
                                                  GimpLayer      *layer,
                                                  PixelRegion    *src,
                                                  PixelRegion    *dest,
                                                  PixelRegion    *mask);
static void   project_intensity_alpha            (GimpProjection *proj,
                                                  GimpLayer      *layer,
                                                  PixelRegion    *src,
                                                  PixelRegion    *dest,
                                                  PixelRegion    *mask);
static void   project_indexed                    (GimpProjection *proj,
                                                  GimpLayer      *layer,
                                                  PixelRegion    *src,
                                                  PixelRegion    *dest,
                                                  PixelRegion    *mask);
static void   project_indexed_alpha              (GimpProjection *proj,
                                                  GimpLayer      *layer,
                                                  PixelRegion    *src,
                                                  PixelRegion    *dest,
                                                  PixelRegion    *mask);
static void   project_channel                    (GimpProjection *proj,
                                                  GimpChannel    *channel,
                                                  PixelRegion    *src,
                                                  PixelRegion    *src2);


/*  public functions  */

void
gimp_projection_construct (GimpProjection *proj,
                           gint            x,
                           gint            y,
                           gint            w,
                           gint            h)
{
  g_return_if_fail (GIMP_IS_PROJECTION (proj));

#if 0
  GimpImage *image = gimp_projectable_get_image (proj->projectable);

  if (gimp_container_num_children (image->layers) == 1) /* a single layer */
    {
      GimpDrawable *layer;
      gint          off_x, off_y;

      layer = GIMP_DRAWABLE (gimp_image_get_layer_by_index (image, 0));

      gimp_item_get_offset (GIMP_ITEM (layer), &off_x, &off_y);

      if (gimp_drawable_has_alpha (layer)                                    &&
          gimp_item_get_visible (GIMP_ITEM (layer))                          &&
          gimp_item_get_width  (GIMP_ITEM (layer)) == image->width           &&
          gimp_item_get_height (GIMP_ITEM (layer)) == image->height          &&
          ! gimp_drawable_is_indexed (layer)                                 &&
          gimp_layer_get_opacity (GIMP_LAYER (layer)) == GIMP_OPACITY_OPAQUE &&
          off_x == 0                                                         &&
          off_y == 0)
        {
          PixelRegion srcPR, destPR;

          g_printerr ("cow-projection!");

          pixel_region_init (&srcPR,
                             gimp_drawable_get_tiles (layer),
                             x, y, w,h, FALSE);
          pixel_region_init (&destPR,
                             gimp_pickable_get_tiles (GIMP_PICKABLE (proj)),
                             x, y, w,h, TRUE);

          copy_region (&srcPR, &destPR);

          proj->construct_flag = TRUE;

          gimp_projection_construct_channels (proj, x, y, w, h);

          return;
        }
    }
#endif

  /*  First, determine if the projection image needs to be
   *  initialized--this is the case when there are no visible
   *  layers that cover the entire canvas--either because layers
   *  are offset or only a floating selection is visible
   */
  gimp_projection_initialize (proj, x, y, w, h);

  /*  call functions which process the list of layers and
   *  the list of channels
   */
  if (proj->use_gegl)
    {
      gimp_projection_construct_gegl (proj, x, y, w, h);
    }
  else
    {
      proj->construct_flag = FALSE;

      gimp_projection_construct_layers (proj, x, y, w, h);
      gimp_projection_construct_channels (proj, x, y, w, h);
    }
}


/*  private functions  */

static void
gimp_projection_construct_gegl (GimpProjection *proj,
                                gint            x,
                                gint            y,
                                gint            w,
                                gint            h)
{
  GeglNode      *sink;
  GeglProcessor *processor;
  GeglRectangle  rect;

  sink = gimp_projection_get_sink_node (proj);

  rect.x      = x;
  rect.y      = y;
  rect.width  = w;
  rect.height = h;

  processor = gegl_node_new_processor (sink, &rect);

  while (gegl_processor_work (processor, NULL));

  g_object_unref (processor);
}

static void
gimp_projection_construct_layers (GimpProjection *proj,
                                  gint            x,
                                  gint            y,
                                  gint            w,
                                  gint            h)
{
  GimpImage *image = gimp_projectable_get_image (proj->projectable);
  GimpLayer *layer;
  GList     *list;
  GList     *reverse_list;
  gint       x1, y1, x2, y2;
  gint       off_x;
  gint       off_y;

  /*  composite the floating selection if it exists  */
  if ((layer = gimp_image_floating_sel (image)))
    floating_sel_composite (layer, x, y, w, h, FALSE);

  reverse_list = NULL;

  for (list = gimp_image_get_layer_iter (image);
       list;
       list = g_list_next (list))
    {
      layer = list->data;

      /*  only add layers that are visible and not floating selections
       *  to the list
       */
      if (! gimp_layer_is_floating_sel (layer) &&
          gimp_item_get_visible (GIMP_ITEM (layer)))
        {
          reverse_list = g_list_prepend (reverse_list, layer);
        }
    }

  for (list = reverse_list; list; list = g_list_next (list))
    {
      GimpLayerMask *mask;
      PixelRegion    src1PR;
      PixelRegion    src2PR;
      PixelRegion    maskPR;

      layer = list->data;
      mask  = gimp_layer_get_mask (layer);

      gimp_item_get_offset (GIMP_ITEM (layer), &off_x, &off_y);

      x1 = CLAMP (off_x, x, x + w);
      y1 = CLAMP (off_y, y, y + h);
      x2 = CLAMP (off_x + gimp_item_get_width  (GIMP_ITEM (layer)), x, x + w);
      y2 = CLAMP (off_y + gimp_item_get_height (GIMP_ITEM (layer)), y, y + h);

      /* configure the pixel regions  */
      pixel_region_init (&src1PR,
                         gimp_pickable_get_tiles (GIMP_PICKABLE (proj)),
                         x1, y1, (x2 - x1), (y2 - y1),
                         TRUE);

      /*  If we're showing the layer mask instead of the layer...  */
      if (mask && gimp_layer_mask_get_show (mask))
        {
          pixel_region_init (&src2PR,
                             gimp_drawable_get_tiles (GIMP_DRAWABLE (mask)),
                             x1 - off_x, y1 - off_y,
                             x2 - x1,    y2 - y1,
                             FALSE);

          copy_gray_to_region (&src2PR, &src1PR);
        }
      /*  Otherwise, normal  */
      else
        {
          PixelRegion *mask_pr = NULL;

          pixel_region_init (&src2PR,
                             gimp_drawable_get_tiles (GIMP_DRAWABLE (layer)),
                             x1 - off_x, y1 - off_y,
                             x2 - x1,    y2 - y1,
                             FALSE);

          if (mask && gimp_layer_mask_get_apply (mask))
            {
              pixel_region_init (&maskPR,
                                 gimp_drawable_get_tiles (GIMP_DRAWABLE (mask)),
                                 x1 - off_x, y1 - off_y,
                                 x2 - x1,    y2 - y1,
                                 FALSE);
              mask_pr = &maskPR;
            }

          /*  Based on the type of the layer, project the layer onto the
           *  projection image...
           */
          switch (gimp_drawable_type (GIMP_DRAWABLE (layer)))
            {
            case GIMP_RGB_IMAGE:
            case GIMP_GRAY_IMAGE:
              project_intensity (proj, layer, &src2PR, &src1PR, mask_pr);
              break;

            case GIMP_RGBA_IMAGE:
            case GIMP_GRAYA_IMAGE:
              project_intensity_alpha (proj, layer, &src2PR, &src1PR, mask_pr);
              break;

            case GIMP_INDEXED_IMAGE:
              project_indexed (proj, layer, &src2PR, &src1PR, mask_pr);
              break;

            case GIMP_INDEXEDA_IMAGE:
              project_indexed_alpha (proj, layer, &src2PR, &src1PR, mask_pr);
              break;

            default:
              break;
            }
        }

      proj->construct_flag = TRUE;  /*  something was projected  */
    }

  g_list_free (reverse_list);
}

static void
gimp_projection_construct_channels (GimpProjection *proj,
                                    gint            x,
                                    gint            y,
                                    gint            w,
                                    gint            h)
{
  GimpImage *image = gimp_projectable_get_image (proj->projectable);
  GList     *list;
  GList     *reverse_list = NULL;

  /*  reverse the channel list  */
  for (list = gimp_image_get_channel_iter (image);
       list;
       list = g_list_next (list))
    {
      reverse_list = g_list_prepend (reverse_list, list->data);
    }

  for (list = reverse_list; list; list = g_list_next (list))
    {
      GimpChannel *channel = list->data;

      if (gimp_item_get_visible (GIMP_ITEM (channel)))
        {
          PixelRegion  src1PR;
          PixelRegion  src2PR;

          /* configure the pixel regions  */
          pixel_region_init (&src1PR,
                             gimp_pickable_get_tiles (GIMP_PICKABLE (proj)),
                             x, y, w, h,
                             TRUE);
          pixel_region_init (&src2PR,
                             gimp_drawable_get_tiles (GIMP_DRAWABLE (channel)),
                             x, y, w, h,
                             FALSE);

          project_channel (proj, channel, &src1PR, &src2PR);

          proj->construct_flag = TRUE;
        }
    }

  g_list_free (reverse_list);
}

/**
 * gimp_projection_initialize:
 * @proj: A #GimpProjection.
 * @x:
 * @y:
 * @w:
 * @h:
 *
 * This function determines whether a visible layer with combine mode
 * Normal provides complete coverage over the specified area.  If not,
 * the projection is initialized to transparent black.
 */
static void
gimp_projection_initialize (GimpProjection *proj,
                            gint            x,
                            gint            y,
                            gint            w,
                            gint            h)
{
  GimpImage *image = gimp_projectable_get_image (proj->projectable);
  GList     *list;
  gboolean   coverage = FALSE;

  for (list = gimp_image_get_layer_iter (image);
       list;
       list = g_list_next (list))
    {
      GimpItem *item = list->data;
      gint      off_x, off_y;

      gimp_item_get_offset (item, &off_x, &off_y);

      if (gimp_item_get_visible (item)                                      &&
          ! gimp_drawable_has_alpha (GIMP_DRAWABLE (item))                  &&
          ! gimp_layer_get_mask (GIMP_LAYER (item))                         &&
          gimp_layer_get_mode (GIMP_LAYER (item)) == GIMP_NORMAL_MODE       &&
          gimp_layer_get_opacity (GIMP_LAYER (item)) == GIMP_OPACITY_OPAQUE &&
          (off_x <= x)                                                      &&
          (off_y <= y)                                                      &&
          (off_x + gimp_item_get_width  (item) >= x + w)                    &&
          (off_y + gimp_item_get_height (item) >= y + h))
        {
          coverage = TRUE;
          break;
        }
    }

  if (! coverage)
    {
      PixelRegion region;

      pixel_region_init (&region,
                         gimp_pickable_get_tiles (GIMP_PICKABLE (proj)),
                         x, y, w, h, TRUE);
      clear_region (&region);
    }
}

static void
project_intensity (GimpProjection *proj,
                   GimpLayer      *layer,
                   PixelRegion    *src,
                   PixelRegion    *dest,
                   PixelRegion    *mask)
{
  GimpImage *image = gimp_projectable_get_image (proj->projectable);

  if (proj->construct_flag)
    {
      combine_regions (dest, src, dest, mask, NULL,
                       gimp_layer_get_opacity (layer) * 255.999,
                       gimp_layer_get_mode (layer),
                       image->visible,
                       COMBINE_INTEN_A_INTEN);
    }
  else
    {
      initial_region (src, dest, mask, NULL,
                      gimp_layer_get_opacity (layer) * 255.999,
                      gimp_layer_get_mode (layer),
                      image->visible,
                      INITIAL_INTENSITY);
    }
}

static void
project_intensity_alpha (GimpProjection *proj,
                         GimpLayer      *layer,
                         PixelRegion    *src,
                         PixelRegion    *dest,
                         PixelRegion    *mask)
{
  GimpImage *image = gimp_projectable_get_image (proj->projectable);

  if (proj->construct_flag)
    {
      combine_regions (dest, src, dest, mask, NULL,
                       gimp_layer_get_opacity (layer) * 255.999,
                       gimp_layer_get_mode (layer),
                       image->visible,
                       COMBINE_INTEN_A_INTEN_A);
    }
  else
    {
      initial_region (src, dest, mask, NULL,
                      gimp_layer_get_opacity (layer) * 255.999,
                      gimp_layer_get_mode (layer),
                      image->visible,
                      INITIAL_INTENSITY_ALPHA);
    }
}

static void
project_indexed (GimpProjection *proj,
                 GimpLayer      *layer,
                 PixelRegion    *src,
                 PixelRegion    *dest,
                 PixelRegion    *mask)
{
  GimpImage    *image    = gimp_projectable_get_image (proj->projectable);
  const guchar *colormap = gimp_image_get_colormap (image);

  g_return_if_fail (colormap != NULL);

  if (proj->construct_flag)
    {
      combine_regions (dest, src, dest, mask, colormap,
                       gimp_layer_get_opacity (layer) * 255.999,
                       gimp_layer_get_mode (layer),
                       image->visible,
                       COMBINE_INTEN_A_INDEXED);
    }
  else
    {
      initial_region (src, dest, mask, colormap,
                      gimp_layer_get_opacity (layer) * 255.999,
                      gimp_layer_get_mode (layer),
                      image->visible,
                      INITIAL_INDEXED);
    }
}

static void
project_indexed_alpha (GimpProjection *proj,
                       GimpLayer      *layer,
                       PixelRegion    *src,
                       PixelRegion    *dest,
                       PixelRegion    *mask)
{
  GimpImage    *image    = gimp_projectable_get_image (proj->projectable);
  const guchar *colormap = gimp_image_get_colormap (image);

  g_return_if_fail (colormap != NULL);

  if (proj->construct_flag)
    {
      combine_regions (dest, src, dest, mask, colormap,
                       gimp_layer_get_opacity (layer) * 255.999,
                       gimp_layer_get_mode (layer),
                       image->visible,
                       COMBINE_INTEN_A_INDEXED_A);
    }
  else
    {
      initial_region (src, dest, mask, colormap,
                      gimp_layer_get_opacity (layer) * 255.999,
                      gimp_layer_get_mode (layer),
                      image->visible,
                      INITIAL_INDEXED_ALPHA);
    }
}

static void
project_channel (GimpProjection *proj,
                 GimpChannel    *channel,
                 PixelRegion    *src,
                 PixelRegion    *src2)
{
  guchar col[3];
  guchar opacity;

  gimp_rgba_get_uchar (&channel->color,
                       &col[0], &col[1], &col[2], &opacity);

  if (proj->construct_flag)
    {
      combine_regions (src, src2, src, NULL, col,
                       opacity,
                       GIMP_NORMAL_MODE,
                       NULL,
                       (gimp_channel_get_show_masked (channel) ?
                        COMBINE_INTEN_A_CHANNEL_MASK :
                        COMBINE_INTEN_A_CHANNEL_SELECTION));
    }
  else
    {
      initial_region (src2, src, NULL, col,
                      opacity,
                      GIMP_NORMAL_MODE,
                      NULL,
                      (gimp_channel_get_show_masked (channel) ?
                       INITIAL_CHANNEL_MASK :
                       INITIAL_CHANNEL_SELECTION));
    }
}