/* GTK - The GIMP Toolkit
 * Copyright (C) 2012 Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#include "gtkcolorscaleprivate.h"

#include "gtkcolorchooserprivate.h"
#include "gtkgesturelongpress.h"
#include "gtkcolorutils.h"
#include "gtkorientable.h"
#include "gtkrangeprivate.h"
#include "gtkstylecontext.h"
#include "gtkaccessible.h"
#include "gtkprivate.h"
#include "gtkintl.h"
#include "gtksnapshot.h"

#include <math.h>

typedef struct
{
  GdkRGBA color;
  GtkColorScaleType type;
  GdkTexture *hue_texture;
} GtkColorScalePrivate;

enum
{
  PROP_ZERO,
  PROP_SCALE_TYPE
};

static void hold_action (GtkGestureLongPress *gesture,
                         gdouble              x,
                         gdouble              y,
                         GtkColorScale       *scale);

G_DEFINE_TYPE_WITH_PRIVATE (GtkColorScale, gtk_color_scale, GTK_TYPE_SCALE)

void
gtk_color_scale_snapshot_trough (GtkColorScale  *scale,
                                 GtkSnapshot    *snapshot,
                                 int             width,
                                 int             height)
{
  GtkColorScalePrivate *priv = gtk_color_scale_get_instance_private (scale);
  GtkWidget *widget = GTK_WIDGET (scale);

  if (width <= 1 || height <= 1)
    return;

  if (priv->hue_texture  &&
      (width != gdk_texture_get_width (priv->hue_texture) ||
       height != gdk_texture_get_height (priv->hue_texture)))
    g_clear_object (&priv->hue_texture);

  if (priv->type == GTK_COLOR_SCALE_HUE)
    {
      if (!priv->hue_texture)
        {
          GdkTexture *texture;
          gint stride;
          GBytes *bytes;
          guchar *data, *p;
          gdouble h;
          gdouble r, g, b;
          gdouble f;
          int hue_x, hue_y;

          stride = width * 3;
          data = g_malloc (width * height * 3);

          f = 1.0 / (height - 1);
          for (hue_y = 0; hue_y < height; hue_y++)
            {
              h = CLAMP (hue_y * f, 0.0, 1.0);
              p = data + hue_y * stride;
              for (hue_x = 0; hue_x < stride; hue_x += 3)
                {
                  gtk_hsv_to_rgb (h, 1, 1, &r, &g, &b);
                  p[hue_x + 0] = CLAMP (r * 255, 0, 255);
                  p[hue_x + 1] = CLAMP (g * 255, 0, 255);
                  p[hue_x + 2] = CLAMP (b * 255, 0, 255);
                }
            }

          bytes = g_bytes_new_take (data, width * height * 3);
          texture = gdk_memory_texture_new (width, height,
                                            GDK_MEMORY_R8G8B8,
                                            bytes,
                                            stride);
          g_bytes_unref (bytes);

          gtk_snapshot_append_texture (snapshot,
                                       texture,
                                       &GRAPHENE_RECT_INIT(0, 0, width, height));
          priv->hue_texture = texture;
        }
      else
        {
          gtk_snapshot_append_texture (snapshot,
                                       priv->hue_texture,
                                       &GRAPHENE_RECT_INIT(0, 0, width, height));
        }
    }
  else if (priv->type == GTK_COLOR_SCALE_ALPHA)
    {
      cairo_t *cr;
      graphene_point_t start, end;

      cr = gtk_snapshot_append_cairo (snapshot,
                                      &GRAPHENE_RECT_INIT(0, 0, width, height));

      if (gtk_orientable_get_orientation (GTK_ORIENTABLE (widget)) == GTK_ORIENTATION_HORIZONTAL &&
          gtk_widget_get_direction (widget) == GTK_TEXT_DIR_RTL)
        {
          cairo_translate (cr, width, 0);
          cairo_scale (cr, -1, 1);
          graphene_point_init (&start, width, 0);
          graphene_point_init (&end, 0, 0);
        }
      else
        {
          graphene_point_init (&start, 0, 0);
          graphene_point_init (&end, width, 0);
        }

      cairo_pattern_t *pattern;
      cairo_matrix_t matrix;
      GdkRGBA *color;

      cairo_set_source_rgb (cr, 0.33, 0.33, 0.33);
      cairo_paint (cr);
      cairo_set_source_rgb (cr, 0.66, 0.66, 0.66);

      pattern = _gtk_color_chooser_get_checkered_pattern ();
      cairo_matrix_init_scale (&matrix, 0.125, 0.125);
      cairo_pattern_set_matrix (pattern, &matrix);
      cairo_mask (cr, pattern);
      cairo_pattern_destroy (pattern);

      cairo_destroy (cr);

      color = &priv->color;

      gtk_snapshot_append_linear_gradient (snapshot,
                                           &GRAPHENE_RECT_INIT(0, 0, width, height),
                                           &start,
                                           &end,
                                           (GskColorStop[2]) {
                                               { 0, { color->red, color->green, color->blue, 0 } },
                                               { 1, { color->red, color->green, color->blue, 1 } },
                                           },
                                           2);
    }
}

static void
gtk_color_scale_init (GtkColorScale *scale)
{
  GtkStyleContext *context;
  GtkGesture *gesture;

  gesture = gtk_gesture_long_press_new ();
  g_signal_connect (gesture, "pressed",
                    G_CALLBACK (hold_action), scale);
  gtk_event_controller_set_propagation_phase (GTK_EVENT_CONTROLLER (gesture),
                                              GTK_PHASE_TARGET);
  gtk_widget_add_controller (GTK_WIDGET (scale), GTK_EVENT_CONTROLLER (gesture));

  context = gtk_widget_get_style_context (GTK_WIDGET (scale));
  gtk_style_context_add_class (context, "color");
}

static void
scale_get_property (GObject    *object,
                    guint       prop_id,
                    GValue     *value,
                    GParamSpec *pspec)
{
  GtkColorScale *scale = GTK_COLOR_SCALE (object);
  GtkColorScalePrivate *priv = gtk_color_scale_get_instance_private (scale);

  switch (prop_id)
    {
    case PROP_SCALE_TYPE:
      g_value_set_int (value, priv->type);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
scale_set_type (GtkColorScale     *scale,
                GtkColorScaleType  type)
{
  GtkColorScalePrivate *priv = gtk_color_scale_get_instance_private (scale);
  AtkObject *atk_obj;

  priv->type = type;

  atk_obj = gtk_widget_get_accessible (GTK_WIDGET (scale));
  if (GTK_IS_ACCESSIBLE (atk_obj))
    {
      if (type == GTK_COLOR_SCALE_HUE)
        atk_object_set_name (atk_obj, C_("Color channel", "Hue"));
      else if (type == GTK_COLOR_SCALE_ALPHA)
        atk_object_set_name (atk_obj, C_("Color channel", "Alpha"));
      atk_object_set_role (atk_obj, ATK_ROLE_COLOR_CHOOSER);
    }
}

static void
scale_set_property (GObject      *object,
                    guint         prop_id,
                    const GValue *value,
                    GParamSpec   *pspec)
{
  GtkColorScale *scale = GTK_COLOR_SCALE (object);

  switch (prop_id)
    {
    case PROP_SCALE_TYPE:
      scale_set_type (scale, (GtkColorScaleType)g_value_get_int (value));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
hold_action (GtkGestureLongPress *gesture,
             gdouble              x,
             gdouble              y,
             GtkColorScale       *scale)
{
  gboolean handled;

  g_signal_emit_by_name (scale, "popup-menu", &handled);
}

static void
scale_finalize (GObject *object)
{
  GtkColorScalePrivate *priv = gtk_color_scale_get_instance_private (GTK_COLOR_SCALE (object));

  g_clear_object (&priv->hue_texture);

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

static void
gtk_color_scale_class_init (GtkColorScaleClass *class)
{
  GObjectClass *object_class = G_OBJECT_CLASS (class);

  object_class->finalize = scale_finalize;
  object_class->get_property = scale_get_property;
  object_class->set_property = scale_set_property;

  g_object_class_install_property (object_class, PROP_SCALE_TYPE,
      g_param_spec_int ("scale-type", P_("Scale type"), P_("Scale type"),
                        0, 1, 0,
                        GTK_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));
}

void
gtk_color_scale_set_rgba (GtkColorScale *scale,
                          const GdkRGBA *color)
{
  GtkColorScalePrivate *priv = gtk_color_scale_get_instance_private (scale);

  priv->color = *color;
  gtk_widget_queue_draw (gtk_range_get_trough_widget (GTK_RANGE (scale)));
}

GtkWidget *
gtk_color_scale_new (GtkAdjustment     *adjustment,
                     GtkColorScaleType  type)
{
  return g_object_new (GTK_TYPE_COLOR_SCALE,
                       "adjustment", adjustment,
                       "draw-value", FALSE,
                       "scale-type", type,
                       NULL);
}