/* eel-accessibility.h - Utility functions for accessibility
 *
 *  Copyright (C) 2002 Anders Carlsson, Sun Microsystems, Inc.
 *
 *  The Eel Library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public License as
 *  published by the Free Software Foundation; either version 2 of the
 *  License, or (at your option) any later version.
 *
 *  The Eel 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
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public
 *  License along with the Eel Library; see the file COPYING.LIB.  If not,
 *  see <http://www.gnu.org/licenses/>.
 *
 *  Authors:
 *       Anders Carlsson <andersca@gnu.org>
 *       Michael Meeks   <michael@ximian.com>
 */
#include <config.h>
#include <gtk/gtk.h>
#include <atk/atkrelationset.h>
#include <eel/eel-accessibility.h>

void
eel_accessibility_set_up_label_widget_relation (GtkWidget *label,
                                                GtkWidget *widget)
{
    AtkObject *atk_widget, *atk_label;

    atk_label = gtk_widget_get_accessible (label);
    atk_widget = gtk_widget_get_accessible (widget);

    /* Create the label -> widget relation */
    atk_object_add_relationship (atk_label, ATK_RELATION_LABEL_FOR, atk_widget);

    /* Create the widget -> label relation */
    atk_object_add_relationship (atk_widget, ATK_RELATION_LABELLED_BY, atk_label);
}

static GQuark
get_quark_gobject (void)
{
    static GQuark quark_accessible_gobject = 0;

    if (!quark_accessible_gobject)
    {
        quark_accessible_gobject = g_quark_from_static_string
                                       ("object-for-accessible");
    }

    return quark_accessible_gobject;
}

/**
 * eel_accessibility_get_gobject:
 * @object: an AtkObject
 *
 * gets the GObject associated with the AtkObject, for which
 * @object provides accessibility support.
 *
 * Return value: the accessible's associated GObject
 **/
static gpointer
eel_accessibility_get_gobject (AtkObject *object)
{
    return g_object_get_qdata (G_OBJECT (object), get_quark_gobject ());
}

static GailTextUtil *
get_simple_text (gpointer object)
{
    GObject *gobject;
    EelAccessibleTextIface *aif;

    if (GTK_IS_ACCESSIBLE (object))
    {
        gobject = G_OBJECT (gtk_accessible_get_widget (GTK_ACCESSIBLE (object)));
    }
    else
    {
        gobject = eel_accessibility_get_gobject (object);
    }

    if (!gobject)
    {
        return NULL;
    }

    aif = EEL_ACCESSIBLE_TEXT_GET_IFACE (gobject);
    if (!aif)
    {
        g_warning ("No accessible text inferface on '%s'",
                   g_type_name_from_instance ((gpointer) gobject));
    }
    else if (aif->get_text)
    {
        return aif->get_text (gobject);
    }

    return NULL;
}

char *
eel_accessibility_text_get_text (AtkText *text,
                                 gint     start_pos,
                                 gint     end_pos)
{
    GailTextUtil *util = get_simple_text (text);
    g_return_val_if_fail (util != NULL, NULL);

    return gail_text_util_get_substring (util, start_pos, end_pos);
}

gunichar
eel_accessibility_text_get_character_at_offset (AtkText *text,
                                                gint     offset)
{
    char *txt, *index;
    gint sucks1 = 0, sucks2 = -1;
    gunichar c;
    GailTextUtil *util = get_simple_text (text);
    g_return_val_if_fail (util != NULL, 0);

    txt = gail_text_util_get_substring (util, sucks1, sucks2);

    index = g_utf8_offset_to_pointer (txt, offset);
    c = g_utf8_get_char (index);
    g_free (txt);

    return c;
}

char *
eel_accessibility_text_get_text_before_offset (AtkText         *text,
                                               gint             offset,
                                               AtkTextBoundary  boundary_type,
                                               gint            *start_offset,
                                               gint            *end_offset)
{
    GailTextUtil *util = get_simple_text (text);
    g_return_val_if_fail (util != NULL, NULL);

    return gail_text_util_get_text (
        util, NULL, GAIL_BEFORE_OFFSET,
        boundary_type, offset, start_offset, end_offset);
}

char *
eel_accessibility_text_get_text_at_offset (AtkText         *text,
                                           gint             offset,
                                           AtkTextBoundary  boundary_type,
                                           gint            *start_offset,
                                           gint            *end_offset)
{
    GailTextUtil *util = get_simple_text (text);
    g_return_val_if_fail (util != NULL, NULL);

    return gail_text_util_get_text (
        util, NULL, GAIL_AT_OFFSET,
        boundary_type, offset, start_offset, end_offset);
}

gchar *
eel_accessibility_text_get_text_after_offset  (AtkText        *text,
                                               gint            offset,
                                               AtkTextBoundary boundary_type,
                                               gint           *start_offset,
                                               gint           *end_offset)
{
    GailTextUtil *util = get_simple_text (text);
    g_return_val_if_fail (util != NULL, NULL);

    return gail_text_util_get_text (
        util, NULL, GAIL_AFTER_OFFSET,
        boundary_type, offset, start_offset, end_offset);
}

gint
eel_accessibility_text_get_character_count (AtkText *text)
{
    GailTextUtil *util = get_simple_text (text);
    g_return_val_if_fail (util != NULL, -1);

    return gtk_text_buffer_get_char_count (util->buffer);
}

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

    if (!type)
    {
        const GTypeInfo tinfo =
        {
            sizeof (AtkTextIface),
            (GBaseInitFunc) NULL,
            (GBaseFinalizeFunc) NULL,
            (GClassInitFunc) NULL,
            (GClassFinalizeFunc) NULL
        };

        type = g_type_register_static (
            G_TYPE_INTERFACE, "EelAccessibleText", &tinfo, 0);
    }

    return type;
}