/* 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 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 <gegl.h>
#include <gtk/gtk.h>

#include "libgimpconfig/gimpconfig.h"
#include "libgimpwidgets/gimpwidgets.h"

#include "tools-types.h"

#include "core/gimpdrawable.h"
#include "core/gimpdrawable-histogram.h"
#include "core/gimperror.h"
#include "core/gimphistogram.h"
#include "core/gimpimage.h"

#include "widgets/gimphelp-ids.h"
#include "widgets/gimphistogrambox.h"
#include "widgets/gimphistogramview.h"

#include "display/gimpdisplay.h"

#include "gimphistogramoptions.h"
#include "gimpthresholdtool.h"

#include "gimp-intl.h"


/*  local function prototypes  */

static void       gimp_threshold_tool_constructed     (GObject           *object);
static void       gimp_threshold_tool_finalize        (GObject           *object);

static gboolean   gimp_threshold_tool_initialize      (GimpTool          *tool,
                                                       GimpDisplay       *display,
                                                       GError           **error);

static gchar    * gimp_threshold_tool_get_operation   (GimpImageMapTool  *im_tool,
                                                       gchar            **title,
                                                       gchar            **description,
                                                       gchar            **undo_desc,
                                                       gchar            **icon_name,
                                                       gchar            **help_id);
static void       gimp_threshold_tool_dialog          (GimpImageMapTool  *im_tool);

static void       gimp_threshold_tool_config_notify   (GObject           *object,
                                                       GParamSpec        *pspec,
                                                       GimpThresholdTool *t_tool);

static void       gimp_threshold_tool_histogram_range (GimpHistogramView *view,
                                                       gint               start,
                                                       gint               end,
                                                       GimpThresholdTool *t_tool);
static void       gimp_threshold_tool_auto_clicked    (GtkWidget         *button,
                                                       GimpThresholdTool *t_tool);


G_DEFINE_TYPE (GimpThresholdTool, gimp_threshold_tool,
               GIMP_TYPE_IMAGE_MAP_TOOL)

#define parent_class gimp_threshold_tool_parent_class


void
gimp_threshold_tool_register (GimpToolRegisterCallback  callback,
                              gpointer                  data)
{
  (* callback) (GIMP_TYPE_THRESHOLD_TOOL,
                GIMP_TYPE_HISTOGRAM_OPTIONS,
                gimp_histogram_options_gui,
                0,
                "gimp-threshold-tool",
                _("Threshold"),
                _("Threshold Tool: Reduce image to two colors using a threshold"),
                N_("_Threshold..."), NULL,
                NULL, GIMP_HELP_TOOL_THRESHOLD,
                GIMP_STOCK_TOOL_THRESHOLD,
                data);
}

static void
gimp_threshold_tool_class_init (GimpThresholdToolClass *klass)
{
  GObjectClass          *object_class  = G_OBJECT_CLASS (klass);
  GimpToolClass         *tool_class    = GIMP_TOOL_CLASS (klass);
  GimpImageMapToolClass *im_tool_class = GIMP_IMAGE_MAP_TOOL_CLASS (klass);

  object_class->constructed          = gimp_threshold_tool_constructed;
  object_class->finalize             = gimp_threshold_tool_finalize;

  tool_class->initialize             = gimp_threshold_tool_initialize;

  im_tool_class->settings_name       = "threshold";
  im_tool_class->import_dialog_title = _("Import Threshold Settings");
  im_tool_class->export_dialog_title = _("Export Threshold Settings");

  im_tool_class->get_operation       = gimp_threshold_tool_get_operation;
  im_tool_class->dialog              = gimp_threshold_tool_dialog;
}

static void
gimp_threshold_tool_init (GimpThresholdTool *t_tool)
{
  t_tool->histogram = gimp_histogram_new (TRUE);
}

static void
gimp_threshold_tool_constructed (GObject *object)
{
  G_OBJECT_CLASS (parent_class)->constructed (object);

  g_signal_connect_object (GIMP_IMAGE_MAP_TOOL (object)->config, "notify",
                           G_CALLBACK (gimp_threshold_tool_config_notify),
                           object, 0);
}

static void
gimp_threshold_tool_finalize (GObject *object)
{
  GimpThresholdTool *t_tool = GIMP_THRESHOLD_TOOL (object);

  if (t_tool->histogram)
    {
      g_object_unref (t_tool->histogram);
      t_tool->histogram = NULL;
    }

  G_OBJECT_CLASS (parent_class)->finalize (object);
}

static gboolean
gimp_threshold_tool_initialize (GimpTool     *tool,
                                GimpDisplay  *display,
                                GError      **error)
{
  GimpThresholdTool *t_tool   = GIMP_THRESHOLD_TOOL (tool);
  GimpImage         *image    = gimp_display_get_image (display);
  GimpDrawable      *drawable = gimp_image_get_active_drawable (image);

  if (! GIMP_TOOL_CLASS (parent_class)->initialize (tool, display, error))
    {
      return FALSE;
    }

  gimp_drawable_calculate_histogram (drawable, t_tool->histogram);
  gimp_histogram_view_set_histogram (t_tool->histogram_box->view,
                                     t_tool->histogram);

  return TRUE;
}

static gchar *
gimp_threshold_tool_get_operation (GimpImageMapTool  *im_tool,
                                   gchar            **title,
                                   gchar            **description,
                                   gchar            **undo_desc,
                                   gchar            **icon_name,
                                   gchar            **help_id)
{
  *description = g_strdup (_("Apply Threshold"));

  return g_strdup ("gimp:threshold");
}


/**********************/
/*  Threshold dialog  */
/**********************/

static void
gimp_threshold_tool_dialog (GimpImageMapTool *im_tool)
{
  GimpThresholdTool *t_tool       = GIMP_THRESHOLD_TOOL (im_tool);
  GimpToolOptions   *tool_options = GIMP_TOOL_GET_OPTIONS (im_tool);
  GtkWidget         *main_vbox;
  GtkWidget         *hbox;
  GtkWidget         *menu;
  GtkWidget         *box;
  GtkWidget         *button;
  gdouble            low;
  gdouble            high;
  gint               n_bins;

  main_vbox = gimp_image_map_tool_dialog_get_vbox (im_tool);

  hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 6);
  gtk_box_pack_start (GTK_BOX (main_vbox), hbox, FALSE, FALSE, 0);
  gtk_widget_show (hbox);

  menu = gimp_prop_enum_icon_box_new (G_OBJECT (tool_options),
                                      "histogram-scale", "gimp-histogram",
                                      0, 0);
  gtk_box_pack_end (GTK_BOX (hbox), menu, FALSE, FALSE, 0);
  gtk_widget_show (menu);

  box = gimp_histogram_box_new ();
  gtk_box_pack_start (GTK_BOX (main_vbox), box, TRUE, TRUE, 0);
  gtk_widget_show (box);

  t_tool->histogram_box = GIMP_HISTOGRAM_BOX (box);

  g_object_get (im_tool->config,
                "low",  &low,
                "high", &high,
                NULL);

  n_bins = gimp_histogram_n_bins (t_tool->histogram);

  gimp_histogram_view_set_range (t_tool->histogram_box->view,
                                 low  * (n_bins - 0.0001),
                                 high * (n_bins - 0.0001));

  g_signal_connect (t_tool->histogram_box->view, "range-changed",
                    G_CALLBACK (gimp_threshold_tool_histogram_range),
                    t_tool);

  gimp_histogram_options_connect_view (GIMP_HISTOGRAM_OPTIONS (tool_options),
                                       t_tool->histogram_box->view);

  hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 6);
  gtk_box_pack_start (GTK_BOX (main_vbox), hbox, FALSE, FALSE, 0);
  gtk_widget_show (hbox);

  button = gtk_button_new_with_mnemonic (_("_Auto"));
  gtk_box_pack_end (GTK_BOX (hbox), button, FALSE, FALSE, 0);
  gimp_help_set_help_data (button, _("Automatically adjust to optimal "
                                     "binarization threshold"), NULL);
  gtk_widget_show (button);

  g_signal_connect (button, "clicked",
                    G_CALLBACK (gimp_threshold_tool_auto_clicked),
                    t_tool);
}

static void
gimp_threshold_tool_config_notify (GObject           *object,
                                   GParamSpec        *pspec,
                                   GimpThresholdTool *t_tool)
{
  gdouble low;
  gdouble high;
  gint    n_bins;

  if (! t_tool->histogram_box)
    return;

  g_object_get (object,
                "low",  &low,
                "high", &high,
                NULL);

  n_bins = gimp_histogram_n_bins (t_tool->histogram);

  gimp_histogram_view_set_range (t_tool->histogram_box->view,
                                 low  * (n_bins - 0.0001),
                                 high * (n_bins - 0.0001));
}

static void
gimp_threshold_tool_histogram_range (GimpHistogramView *widget,
                                     gint               start,
                                     gint               end,
                                     GimpThresholdTool *t_tool)
{
  GimpImageMapTool *im_tool = GIMP_IMAGE_MAP_TOOL (t_tool);
  gint              n_bins  = gimp_histogram_n_bins (t_tool->histogram);
  gdouble           low     = (gdouble) start / (n_bins - 1);
  gdouble           high    = (gdouble) end   / (n_bins - 1);
  gdouble           config_low;
  gdouble           config_high;

  g_object_get (im_tool->config,
                "low",  &config_low,
                "high", &config_high,
                NULL);

  if (low  != config_low ||
      high != config_high)
    {
      g_object_set (im_tool->config,
                    "low",  low,
                    "high", high,
                    NULL);
    }
}

static void
gimp_threshold_tool_auto_clicked (GtkWidget         *button,
                                  GimpThresholdTool *t_tool)
{
  GimpDrawable *drawable = GIMP_IMAGE_MAP_TOOL (t_tool)->drawable;
  gint          n_bins   = gimp_histogram_n_bins (t_tool->histogram);
  gdouble       low;

  low = gimp_histogram_get_threshold (t_tool->histogram,
                                      gimp_drawable_is_rgb (drawable) ?
                                      GIMP_HISTOGRAM_RGB :
                                      GIMP_HISTOGRAM_VALUE,
                                      0, n_bins - 1);

  gimp_histogram_view_set_range (t_tool->histogram_box->view,
                                 low, n_bins - 1);
}