/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */

/* caja-undo.c - public interface for objects that implement
 *                   undoable actions -- works across components
 *
 * Copyright (C) 2000 Eazel, Inc.
 *
 * This 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.
 *
 * 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library 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.
 *
 * Author: Darin Adler <darin@bentspoon.com>
 */

#include <config.h>
#include "caja-undo.h"

#include "caja-undo-private.h"
#include "caja-undo-transaction.h"
#include <gtk/gtk.h>

#define CAJA_UNDO_MANAGER_DATA "Caja undo manager"

/* Register a simple undo action by calling caja_undo_register_full. */
void
caja_undo_register (GObject *target,
                    CajaUndoCallback callback,
                    gpointer callback_data,
                    GDestroyNotify callback_data_destroy_notify,
                    const char *operation_name,
                    const char *undo_menu_item_label,
                    const char *undo_menu_item_hint,
                    const char *redo_menu_item_label,
                    const char *redo_menu_item_hint)
{
    CajaUndoAtom atom;
    GList single_atom_list;

    g_return_if_fail (G_IS_OBJECT (target));
    g_return_if_fail (callback != NULL);

    /* Make an atom. */
    atom.target = target;
    atom.callback = callback;
    atom.callback_data = callback_data;
    atom.callback_data_destroy_notify = callback_data_destroy_notify;

    /* Make a single-atom list. */
    single_atom_list.data = &atom;
    single_atom_list.next = NULL;
    single_atom_list.prev = NULL;

    /* Call the full version of the registration function,
     * using the undo target as the place to search for the
     * undo manager.
     */
    caja_undo_register_full (&single_atom_list,
                             target,
                             operation_name,
                             undo_menu_item_label,
                             undo_menu_item_hint,
                             redo_menu_item_label,
                             redo_menu_item_hint);
}

/* Register an undo action. */
void
caja_undo_register_full (GList *atoms,
                         GObject *undo_manager_search_start_object,
                         const char *operation_name,
                         const char *undo_menu_item_label,
                         const char *undo_menu_item_hint,
                         const char *redo_menu_item_label,
                         const char *redo_menu_item_hint)
{
    CajaUndoTransaction *transaction;
    GList *p;

    g_return_if_fail (atoms != NULL);
    g_return_if_fail (G_IS_OBJECT (undo_manager_search_start_object));

    /* Create an undo transaction */
    transaction = caja_undo_transaction_new (operation_name,
                  undo_menu_item_label,
                  undo_menu_item_hint,
                  redo_menu_item_label,
                  redo_menu_item_hint);
    for (p = atoms; p != NULL; p = p->next)
    {
        caja_undo_transaction_add_atom (transaction, p->data);
    }
    caja_undo_transaction_add_to_undo_manager
    (transaction,
     caja_undo_get_undo_manager (undo_manager_search_start_object));

    /* Now we are done with the transaction.
     * If the undo manager is holding it, then this will not destroy it.
     */
    g_object_unref (transaction);
}

/* Cover for forgetting about all undo relating to a particular target. */
void
caja_undo_unregister (GObject *target)
{
    /* Perhaps this should also unregister all children if called on a
     * GtkContainer? That might be handy.
     */
    caja_undo_transaction_unregister_object (target);
}

void
caja_undo (GObject *undo_manager_search_start_object)
{
    CajaUndoManager *manager;

    g_return_if_fail (G_IS_OBJECT (undo_manager_search_start_object));

    manager = caja_undo_get_undo_manager (undo_manager_search_start_object);
    if (manager != NULL)
    {
        caja_undo_manager_undo (manager);
    }
}

CajaUndoManager *
caja_undo_get_undo_manager (GObject *start_object)
{
    CajaUndoManager *manager;
    GtkWidget *parent;
    GtkWindow *transient_parent;

    if (start_object == NULL)
    {
        return NULL;
    }

    g_return_val_if_fail (G_IS_OBJECT (start_object), NULL);

    /* Check for an undo manager right here. */
    manager = g_object_get_data (start_object, CAJA_UNDO_MANAGER_DATA);
    if (manager != NULL)
    {
        return manager;
    }

    /* Check for undo manager up the parent chain. */
    if (GTK_IS_WIDGET (start_object))
    {
        parent = gtk_widget_get_parent (GTK_WIDGET (start_object));
        if (parent != NULL)
        {
            manager = caja_undo_get_undo_manager (G_OBJECT (parent));
            if (manager != NULL)
            {
                return manager;
            }
        }

        /* Check for undo manager in our window's parent. */
        if (GTK_IS_WINDOW (start_object))
        {
            transient_parent = gtk_window_get_transient_for (GTK_WINDOW (start_object));
            if (transient_parent != NULL)
            {
                manager = caja_undo_get_undo_manager (G_OBJECT (transient_parent));
                if (manager != NULL)
                {
                    return manager;
                }
            }
        }
    }

    /* Found nothing. I can live with that. */
    return NULL;
}

void
caja_undo_attach_undo_manager (GObject *object,
                               CajaUndoManager *manager)
{
    g_return_if_fail (G_IS_OBJECT (object));

    if (manager == NULL)
    {
        g_object_set_data (object, CAJA_UNDO_MANAGER_DATA, NULL);
    }
    else
    {
        g_object_ref (manager);
        g_object_set_data_full
        (object, CAJA_UNDO_MANAGER_DATA,
         manager, g_object_unref);
    }
}

/* Copy a reference to the undo manager fromone object to another. */
void
caja_undo_share_undo_manager (GObject *destination_object,
                              GObject *source_object)
{
    CajaUndoManager *manager;

    manager = caja_undo_get_undo_manager (source_object);
    caja_undo_attach_undo_manager (destination_object, manager);
}
