/* GAIL - The GNOME Accessibility Enabling Library
 * Copyright 2001, 2002, 2003 Sun Microsystems 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, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <string.h>
#include <gtk/gtk.h>
#include "gailscrolledwindow.h"


static void         gail_scrolled_window_class_init     (GailScrolledWindowClass  *klass); 
static void         gail_scrolled_window_real_initialize
                                                        (AtkObject     *obj,
                                                         gpointer      data);

static gint         gail_scrolled_window_get_n_children (AtkObject     *object);
static AtkObject*   gail_scrolled_window_ref_child      (AtkObject     *obj,
                                                         gint          child);
static void         gail_scrolled_window_scrollbar_visibility_changed 
                                                        (GObject       *object,
                                                         GParamSpec    *pspec,
                                                         gpointer      user_data);

static GailContainerClass *parent_class = NULL;

GType
gail_scrolled_window_get_type (void)
{
  static GType type = 0;

  if (!type)
    {
      static const GTypeInfo tinfo =
      {
        sizeof (GailScrolledWindowClass),
        (GBaseInitFunc) NULL, /* base init */
        (GBaseFinalizeFunc) NULL, /* base finalize */
        (GClassInitFunc) gail_scrolled_window_class_init, /* class init */
        (GClassFinalizeFunc) NULL, /* class finalize */
        NULL, /* class data */
        sizeof (GailScrolledWindow), /* instance size */
        0, /* nb preallocs */
        (GInstanceInitFunc) NULL, /* instance init */
        NULL /* value table */
      };

      type = g_type_register_static (GAIL_TYPE_CONTAINER,
                                     "GailScrolledWindow", &tinfo, 0);
    }
  return type;
}

static void
gail_scrolled_window_class_init (GailScrolledWindowClass *klass)
{
  AtkObjectClass  *class = ATK_OBJECT_CLASS (klass);

  parent_class = g_type_class_peek_parent (klass);

  class->get_n_children = gail_scrolled_window_get_n_children;
  class->ref_child = gail_scrolled_window_ref_child;
  class->initialize = gail_scrolled_window_real_initialize;
}

AtkObject* 
gail_scrolled_window_new (GtkWidget *widget)
{
  GObject *object;
  AtkObject *accessible;
  
  g_return_val_if_fail (GTK_IS_SCROLLED_WINDOW (widget), NULL);

  object = g_object_new (GAIL_TYPE_SCROLLED_WINDOW, NULL);

  accessible = ATK_OBJECT (object);
  atk_object_initialize (accessible, widget);

  return accessible;
}

static void
gail_scrolled_window_real_initialize (AtkObject *obj,
                                      gpointer  data)
{
  GtkScrolledWindow *window;

  ATK_OBJECT_CLASS (parent_class)->initialize (obj, data);

  window = GTK_SCROLLED_WINDOW (data);
  g_signal_connect_data (window->hscrollbar, "notify::visible",
    (GCallback)gail_scrolled_window_scrollbar_visibility_changed, 
    obj, NULL, FALSE);
  g_signal_connect_data (window->vscrollbar, "notify::visible",
    (GCallback)gail_scrolled_window_scrollbar_visibility_changed, 
    obj, NULL, FALSE);

  obj->role = ATK_ROLE_SCROLL_PANE;
}

static gint
gail_scrolled_window_get_n_children (AtkObject *object)
{
  GtkWidget *widget;
  GtkScrolledWindow *gtk_window;
  GList *children;
  gint n_children;
 
  widget = GTK_ACCESSIBLE (object)->widget;
  if (widget == NULL)
    /* Object is defunct */
    return 0;

  gtk_window = GTK_SCROLLED_WINDOW (widget);
   
  /* Get the number of children returned by the backing GtkScrolledWindow */

  children = gtk_container_get_children (GTK_CONTAINER(gtk_window));
  n_children = g_list_length (children);
  g_list_free (children);
  
  /* Add one to the count for each visible scrollbar */

  if (gtk_window->hscrollbar_visible)
    n_children++;
  if (gtk_window->vscrollbar_visible)
    n_children++;
  return n_children;
}

static AtkObject *
gail_scrolled_window_ref_child (AtkObject *obj, 
                                gint      child)
{
  GtkWidget *widget;
  GtkScrolledWindow *gtk_window;
  GList *children, *tmp_list;
  gint n_children;
  AtkObject  *accessible = NULL;

  g_return_val_if_fail (child >= 0, NULL);

  widget = GTK_ACCESSIBLE (obj)->widget;
  if (widget == NULL)
    /* Object is defunct */
    return NULL;

  gtk_window = GTK_SCROLLED_WINDOW (widget);

  children = gtk_container_get_children (GTK_CONTAINER (gtk_window));
  n_children = g_list_length (children);

  if (child == n_children)
    {
      if (gtk_window->hscrollbar_visible)
        accessible = gtk_widget_get_accessible (gtk_window->hscrollbar);
      else if (gtk_window->vscrollbar_visible)
        accessible = gtk_widget_get_accessible (gtk_window->vscrollbar);
    }
  else if (child == n_children+1 && 
           gtk_window->hscrollbar_visible &&
           gtk_window->vscrollbar_visible)
    accessible = gtk_widget_get_accessible (gtk_window->vscrollbar);
  else if (child < n_children)
    {
      tmp_list = g_list_nth (children, child);
      if (tmp_list)
	accessible = gtk_widget_get_accessible (
		GTK_WIDGET (tmp_list->data));
    }

  g_list_free (children);
  if (accessible)
    g_object_ref (accessible);
  return accessible; 
}

static void
gail_scrolled_window_scrollbar_visibility_changed (GObject    *object,
                                                   GParamSpec *pspec,
                                                   gpointer   user_data)
{
  if (!strcmp (pspec->name, "visible"))
    {
      gint index;
      gint n_children;
      gboolean child_added = FALSE;
      GList *children;
      AtkObject *child;
      GtkScrolledWindow *gtk_window;
      GailScrolledWindow *gail_window = GAIL_SCROLLED_WINDOW (user_data);
      gchar *signal_name;

      gtk_window = GTK_SCROLLED_WINDOW (GTK_ACCESSIBLE (user_data)->widget);
      if (gtk_window == NULL)
        return;
      children = gtk_container_get_children (GTK_CONTAINER (gtk_window));
      index = n_children = g_list_length (children);
      g_list_free (children);

      if ((gpointer) object == (gpointer) (gtk_window->hscrollbar))
        {
          if (gtk_window->hscrollbar_visible)
            child_added = TRUE;

          child = gtk_widget_get_accessible (gtk_window->hscrollbar);
        }
      else if ((gpointer) object == (gpointer) (gtk_window->vscrollbar))
        {
          if (gtk_window->vscrollbar_visible)
            child_added = TRUE;

          child = gtk_widget_get_accessible (gtk_window->vscrollbar);
          if (gtk_window->hscrollbar_visible)
            index = n_children+1;
        }
      else 
        {
          g_assert_not_reached ();
          return;
        }

      if (child_added)
        signal_name = "children_changed::add";
      else
        signal_name = "children_changed::delete";

      g_signal_emit_by_name (gail_window, signal_name, index, child, NULL);
    }
}