/*
 * Copyright © 2011 Canonical Limited
 *
 * 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 licence, 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.
 *
 * Author: Ryan Lortie <desrt@desrt.ca>
 */

#include "config.h"

#include "gtkapplicationwindow.h"

#include "gtkseparatormenuitem.h"
#include "gtkmodelmenuitem.h"
#include "gtkcheckmenuitem.h"
#include "gtkmenubar.h"
#include "gactionmuxer.h"
#include "gtkintl.h"

/**
 * SECTION:gtkapplicationwindow
 * @title: GtkApplicationWindow
 * @short_description: GtkWindow subclass with GtkApplication support
 *
 * GtkApplicationWindow is a #GtkWindow subclass that offers some
 * extra functionality for better integration with #GtkApplication
 * features.  Notably, it can handle both the application menu as well
 * as the menubar.  See g_application_set_app_menu() and
 * g_application_set_menubar().
 *
 * This class implements the #GActionGroup and #GActionMap interfaces,
 * to let you add window-specific actions that will be exported by the
 * associated #GtkApplication, together with its application-wide
 * actions.  Window-specific actions are prefixed with the "win."
 * prefix and application-wide actions are prefixed with the "app."
 * prefix.  Actions must be addressed with the prefixed name when
 * referring to them from a #GMenuModel.
 *
 * If the desktop environment does not display the application menu
 * as part of the desktop shell, then #GApplicationWindow will
 * automatically show the menu as part of a menubar. This behaviour
 * can be overridden with the #GtkApplicationWindow:show-app-menu
 * property.
 */
struct _GtkApplicationWindowPrivate
{
  GSimpleActionGroup *actions;
  GtkWidget *menubar;

  GMenu *app_menu_section;
  GMenu *menubar_section;
  gboolean show_menubar;
};

static GtkWidget *
gtk_application_window_create_menubar (GMenuModel        *model,
                                       GActionObservable *actions);


static void
gtk_application_window_update_menubar (GtkApplicationWindow *window)
{
  gboolean should_have_menubar;
  gboolean have_menubar;

  have_menubar = window->priv->menubar != NULL;

  should_have_menubar = window->priv->show_menubar &&
                        (g_menu_model_get_n_items (G_MENU_MODEL (window->priv->app_menu_section)) ||
                         g_menu_model_get_n_items (G_MENU_MODEL (window->priv->menubar_section)));

  if (have_menubar && !should_have_menubar)
    {
      gtk_widget_unparent (window->priv->menubar);
      window->priv->menubar = NULL;

      gtk_widget_queue_resize (GTK_WIDGET (window));
    }

  if (!have_menubar && should_have_menubar)
    {
      GActionMuxer *muxer;
      GMenu *combined;

      muxer = g_action_muxer_new ();
      g_action_muxer_insert (muxer, "app", G_ACTION_GROUP (gtk_window_get_application (GTK_WINDOW (window))));
      g_action_muxer_insert (muxer, "win", G_ACTION_GROUP (window));

      combined = g_menu_new ();
      g_menu_append_section (combined, NULL, G_MENU_MODEL (window->priv->app_menu_section));
      g_menu_append_section (combined, NULL, G_MENU_MODEL (window->priv->menubar_section));

      window->priv->menubar = gtk_application_window_create_menubar (G_MENU_MODEL (combined), G_ACTION_OBSERVABLE (muxer));
      gtk_widget_set_parent (window->priv->menubar, GTK_WIDGET (window));
      gtk_widget_show_all (window->priv->menubar);
      g_object_unref (combined);
      g_object_unref (muxer);

      gtk_widget_queue_resize (GTK_WIDGET (window));
    }
}

static void
gtk_application_window_update_shell_shows_app_menu (GtkApplicationWindow *window)
{
  gboolean shown_by_shell;

  g_object_get (gtk_widget_get_settings (GTK_WIDGET (window)), "gtk-shell-shows-app-menu", &shown_by_shell, NULL);

  if (shown_by_shell)
    {
      /* the shell shows it, so don't show it locally */
      if (g_menu_model_get_n_items (G_MENU_MODEL (window->priv->app_menu_section)) != 0)
        g_menu_remove (window->priv->app_menu_section, 0);
    }
  else
    {
      /* the shell does not show it, so make sure we show it */
      if (g_menu_model_get_n_items (G_MENU_MODEL (window->priv->app_menu_section)) == 0)
        {
          GMenuModel *app_menu;

          app_menu = g_application_get_app_menu (G_APPLICATION (gtk_window_get_application (GTK_WINDOW (window))));

          if (app_menu != NULL)
            g_menu_append_submenu (window->priv->app_menu_section, _("Application"), app_menu);
        }
    }
}

static void
gtk_application_window_update_shell_shows_menubar (GtkApplicationWindow *window)
{
  gboolean shown_by_shell;

  g_object_get (gtk_widget_get_settings (GTK_WIDGET (window)), "gtk-shell-shows-menubar", &shown_by_shell, NULL);

  if (shown_by_shell)
    {
      /* the shell shows it, so don't show it locally */
      if (g_menu_model_get_n_items (G_MENU_MODEL (window->priv->menubar_section)) != 0)
        g_menu_remove (window->priv->menubar_section, 0);
    }
  else
    {
      /* the shell does not show it, so make sure we show it */
      if (g_menu_model_get_n_items (G_MENU_MODEL (window->priv->menubar_section)) == 0)
        {
          GMenuModel *menubar;

          menubar = g_application_get_menubar (G_APPLICATION (gtk_window_get_application (GTK_WINDOW (window))));

          if (menubar != NULL)
            g_menu_append_section (window->priv->menubar_section, NULL, menubar);
        }
    }
}

static void
gtk_application_window_shell_shows_app_menu_changed (GObject    *object,
                                                     GParamSpec *pspec,
                                                     gpointer    user_data)
{
  GtkApplicationWindow *window = user_data;

  gtk_application_window_update_shell_shows_app_menu (window);
  gtk_application_window_update_menubar (window);
}

static void
gtk_application_window_shell_shows_menubar_changed (GObject    *object,
                                                    GParamSpec *pspec,
                                                    gpointer    user_data)
{
  GtkApplicationWindow *window = user_data;

  gtk_application_window_update_shell_shows_menubar (window);
  gtk_application_window_update_menubar (window);
}

static gchar **
gtk_application_window_list_actions (GActionGroup *group)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (group);

  return g_action_group_list_actions (G_ACTION_GROUP (window->priv->actions));
}

static gboolean
gtk_application_window_query_action (GActionGroup        *group,
                                     const gchar         *action_name,
                                     gboolean            *enabled,
                                     const GVariantType **parameter_type,
                                     const GVariantType **state_type,
                                     GVariant           **state_hint,
                                     GVariant           **state)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (group);

  return g_action_group_query_action (G_ACTION_GROUP (window->priv->actions),
                                      action_name, enabled, parameter_type, state_type, state_hint, state);
}

static void
gtk_application_window_activate_action (GActionGroup *group,
                                        const gchar  *action_name,
                                        GVariant     *parameter)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (group);

  return g_action_group_activate_action (G_ACTION_GROUP (window->priv->actions), action_name, parameter);
}

static void
gtk_application_window_change_action_state (GActionGroup *group,
                                            const gchar  *action_name,
                                            GVariant     *state)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (group);

  return g_action_group_change_action_state (G_ACTION_GROUP (window->priv->actions), action_name, state);
}

static GAction *
gtk_application_window_lookup_action (GActionMap  *action_map,
                                      const gchar *action_name)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (action_map);

  return g_action_map_lookup_action (G_ACTION_MAP (window->priv->actions), action_name);
}

static void
gtk_application_window_add_action (GActionMap *action_map,
                                   GAction    *action)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (action_map);

  g_action_map_add_action (G_ACTION_MAP (window->priv->actions), action);
}

static void
gtk_application_window_remove_action (GActionMap  *action_map,
                                      const gchar *action_name)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (action_map);

  g_action_map_remove_action (G_ACTION_MAP (window->priv->actions), action_name);
}

static void
gtk_application_window_group_iface_init (GActionGroupInterface *iface)
{
  iface->list_actions = gtk_application_window_list_actions;
  iface->query_action = gtk_application_window_query_action;
  iface->activate_action = gtk_application_window_activate_action;
  iface->change_action_state = gtk_application_window_change_action_state;
}

static void
gtk_application_window_map_iface_init (GActionMapInterface *iface)
{
  iface->lookup_action = gtk_application_window_lookup_action;
  iface->add_action = gtk_application_window_add_action;
  iface->remove_action = gtk_application_window_remove_action;
}

G_DEFINE_TYPE_WITH_CODE (GtkApplicationWindow, gtk_application_window, GTK_TYPE_WINDOW,
                         G_IMPLEMENT_INTERFACE (G_TYPE_ACTION_GROUP, gtk_application_window_group_iface_init)
                         G_IMPLEMENT_INTERFACE (G_TYPE_ACTION_MAP, gtk_application_window_map_iface_init))

enum {
  PROP_0,
  PROP_SHOW_MENUBAR,
  N_PROPS
};
static GParamSpec *gtk_application_window_properties[N_PROPS];

static void
gtk_application_window_real_get_preferred_height (GtkWidget *widget,
                                                  gint      *minimum_height,
                                                  gint      *natural_height)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (widget);

  GTK_WIDGET_CLASS (gtk_application_window_parent_class)
    ->get_preferred_height (widget, minimum_height, natural_height);

  if (window->priv->menubar != NULL)
    {
      gint menubar_min_height, menubar_nat_height;

      gtk_widget_get_preferred_height (window->priv->menubar, &menubar_min_height, &menubar_nat_height);
      *minimum_height += menubar_min_height;
      *natural_height += menubar_nat_height;
    }
}

static void
gtk_application_window_real_get_preferred_height_for_width (GtkWidget *widget,
                                                            gint       width,
                                                            gint      *minimum_height,
                                                            gint      *natural_height)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (widget);

  GTK_WIDGET_CLASS (gtk_application_window_parent_class)
    ->get_preferred_height_for_width (widget, width, minimum_height, natural_height);

  if (window->priv->menubar != NULL)
    {
      gint menubar_min_height, menubar_nat_height;

      gtk_widget_get_preferred_height_for_width (window->priv->menubar, width, &menubar_min_height, &menubar_nat_height);
      *minimum_height += menubar_min_height;
      *natural_height += menubar_nat_height;
    }
}

static void
gtk_application_window_real_get_preferred_width (GtkWidget *widget,
                                                 gint      *minimum_width,
                                                 gint      *natural_width)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (widget);

  GTK_WIDGET_CLASS (gtk_application_window_parent_class)
    ->get_preferred_width (widget, minimum_width, natural_width);

  if (window->priv->menubar != NULL)
    {
      gint menubar_min_width, menubar_nat_width;

      gtk_widget_get_preferred_width (window->priv->menubar, &menubar_min_width, &menubar_nat_width);
      *minimum_width = MAX (*minimum_width, menubar_min_width);
      *natural_width = MAX (*natural_width, menubar_nat_width);
    }
}

static void
gtk_application_window_real_get_preferred_width_for_height (GtkWidget *widget,
                                                            gint       height,
                                                            gint      *minimum_width,
                                                            gint      *natural_width)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (widget);

  GTK_WIDGET_CLASS (gtk_application_window_parent_class)
    ->get_preferred_width_for_height (widget, height, minimum_width, natural_width);

  if (window->priv->menubar != NULL)
    {
      gint menubar_min_width, menubar_nat_width;

      gtk_widget_get_preferred_width_for_height (window->priv->menubar, height, &menubar_min_width, &menubar_nat_width);
      *minimum_width = MAX (*minimum_width, menubar_min_width);
      *natural_width = MAX (*natural_width, menubar_nat_width);
    }
}

static void
gtk_application_window_real_size_allocate (GtkWidget     *widget,
                                           GtkAllocation *allocation)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (widget);

  if (window->priv->menubar != NULL)
    {
      GtkAllocation menubar_allocation = *allocation;
      gint menubar_min_height, menubar_nat_height;
      GtkWidget *child;

      gtk_widget_get_preferred_height_for_width (window->priv->menubar, allocation->width, &menubar_min_height, &menubar_nat_height);

      menubar_allocation.height = menubar_min_height;
      gtk_widget_size_allocate (window->priv->menubar, &menubar_allocation);

      child = gtk_bin_get_child (GTK_BIN (window));
      if (child != NULL && gtk_widget_get_visible (child))
        {
          GtkAllocation child_allocation = *allocation;
          gint border_width;

          child_allocation.height = MAX (1, child_allocation.height - menubar_min_height);

          border_width = gtk_container_get_border_width (GTK_CONTAINER (window));
          child_allocation.x += border_width;
          child_allocation.y += border_width + menubar_min_height;
          child_allocation.width -= border_width * 2;
          child_allocation.height -= border_width * 2 - menubar_min_height;
          gtk_widget_size_allocate (child, &child_allocation);
        }

      gtk_widget_set_allocation (widget, allocation);
    }
  else
    GTK_WIDGET_CLASS (gtk_application_window_parent_class)
      ->size_allocate (widget, allocation);
}

static void
gtk_application_window_real_realize (GtkWidget *widget)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (widget);

  gtk_application_window_update_shell_shows_app_menu (window);
  gtk_application_window_update_shell_shows_menubar (window);
  gtk_application_window_update_menubar (window);

  GTK_WIDGET_CLASS (gtk_application_window_parent_class)
    ->realize (widget);
}

static void
gtk_application_window_real_map (GtkWidget *widget)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (widget);

  /* XXX could eliminate this by tweaking gtk_window_map */
  if (window->priv->menubar)
    gtk_widget_map (window->priv->menubar);

  GTK_WIDGET_CLASS (gtk_application_window_parent_class)
    ->map (widget);
}

static void
gtk_application_window_real_forall_internal (GtkContainer *container,
                                             gboolean      include_internal,
                                             GtkCallback   callback,
                                             gpointer      user_data)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (container);

  if (window->priv->menubar)
    callback (window->priv->menubar, user_data);

  GTK_CONTAINER_CLASS (gtk_application_window_parent_class)
    ->forall (container, include_internal, callback, user_data);
}


static void
gtk_application_window_get_property (GObject    *object,
                                     guint       prop_id,
                                     GValue     *value,
                                     GParamSpec *pspec)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (object);

  switch (prop_id)
    {
    case PROP_SHOW_MENUBAR:
      g_value_set_boolean (value, window->priv->show_menubar);
      break;

    default:
      g_assert_not_reached ();
    }
}

static void
gtk_application_window_set_property (GObject      *object,
                                     guint         prop_id,
                                     const GValue *value,
                                     GParamSpec   *pspec)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (object);

  switch (prop_id)
    {
    case PROP_SHOW_MENUBAR:
      gtk_application_window_set_show_menubar (window, g_value_get_boolean (value));
      break;

    default:
      g_assert_not_reached ();
    }
}

static void
gtk_application_window_dispose (GObject *object)
{
  GtkApplicationWindow *window = GTK_APPLICATION_WINDOW (object);

  if (window->priv->menubar)
    {
      gtk_widget_unparent (window->priv->menubar);
      window->priv->menubar = NULL;
    }

  g_clear_object (&window->priv->app_menu_section);
  g_clear_object (&window->priv->menubar_section);
  g_clear_object (&window->priv->actions);

  G_OBJECT_CLASS (gtk_application_window_parent_class)
    ->dispose (object);
}

static void
gtk_application_window_init (GtkApplicationWindow *window)
{
  window->priv = G_TYPE_INSTANCE_GET_PRIVATE (window, GTK_TYPE_APPLICATION_WINDOW, GtkApplicationWindowPrivate);

  window->priv->actions = g_simple_action_group_new ();
  window->priv->app_menu_section = g_menu_new ();
  window->priv->menubar_section = g_menu_new ();

  /* window->priv->actions is the one and only ref on the group, so when
   * we dispose, the action group will die, disconnecting all signals.
   */
  g_signal_connect_swapped (window->priv->actions, "action-added",
                            G_CALLBACK (g_action_group_action_added), window);
  g_signal_connect_swapped (window->priv->actions, "action-enabled-changed",
                            G_CALLBACK (g_action_group_action_enabled_changed), window);
  g_signal_connect_swapped (window->priv->actions, "action-state-changed",
                            G_CALLBACK (g_action_group_action_state_changed), window);
  g_signal_connect_swapped (window->priv->actions, "action-removed",
                            G_CALLBACK (g_action_group_action_removed), window);
}

static void
gtk_application_window_class_init (GtkApplicationWindowClass *class)
{
  GtkContainerClass *container_class = GTK_CONTAINER_CLASS (class);
  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (class);
  GObjectClass *object_class = G_OBJECT_CLASS (class);

  container_class->forall = gtk_application_window_real_forall_internal;
  widget_class->get_preferred_height = gtk_application_window_real_get_preferred_height;
  widget_class->get_preferred_height_for_width = gtk_application_window_real_get_preferred_height_for_width;
  widget_class->get_preferred_width = gtk_application_window_real_get_preferred_width;
  widget_class->get_preferred_width_for_height = gtk_application_window_real_get_preferred_width_for_height;
  widget_class->size_allocate = gtk_application_window_real_size_allocate;
  widget_class->realize = gtk_application_window_real_realize;
  widget_class->map = gtk_application_window_real_map;
  object_class->get_property = gtk_application_window_get_property;
  object_class->set_property = gtk_application_window_set_property;
  object_class->dispose = gtk_application_window_dispose;

  gtk_application_window_properties[PROP_SHOW_MENUBAR] =
    g_param_spec_boolean ("show-menubar",
                          P_("Show a menubar"),
                          P_("TRUE if the application's menus should be included "
                             "in the menubar at the top of the window"),
                          TRUE, G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS | G_PARAM_READWRITE);
  g_object_class_install_properties (object_class, N_PROPS, gtk_application_window_properties);
  g_type_class_add_private (class, sizeof (GtkApplicationWindowPrivate));
}

/**
 * gtk_application_window_new:
 * @application: a #GtkApplication
 *
 * Creates a new #GtkApplicationWindow.
 *
 * Returns: a newly created #GtkApplicationWindow
 *
 * Since: 3.4
 */
GtkWidget *
gtk_application_window_new (GtkApplication *application)
{
  g_return_val_if_fail (GTK_IS_APPLICATION (application), NULL);

  return g_object_new (GTK_TYPE_APPLICATION_WINDOW,
                       "application", application,
                       NULL);
}

gboolean
gtk_application_window_get_show_menubar (GtkApplicationWindow *window)
{
  return window->priv->show_menubar;
}

void
gtk_application_window_set_show_menubar (GtkApplicationWindow *window,
                                         gboolean              show_menubar)
{
  g_return_if_fail (GTK_IS_APPLICATION_WINDOW (window));

  show_menubar = !!show_menubar;

  if (window->priv->show_menubar != show_menubar)
    {
      window->priv->show_menubar = show_menubar;

      gtk_application_window_update_menubar (window);

      g_object_notify_by_pspec (G_OBJECT (window), gtk_application_window_properties[PROP_SHOW_MENUBAR]);
    }
}

/* GtkMenu construction {{{1 */

static void populate_menu_from_model (GtkMenuShell *menu,
                                      GMenuModel   *model,
                                      GActionObservable *actions);

static void
append_items_from_model (GtkMenuShell      *menu,
                         GMenuModel        *model,
                         GActionObservable *actions,
                         gboolean          *need_separator,
                         const gchar       *heading)
{
  gint n;
  gint i;
  GtkWidget *w;
  GtkMenuItem *menuitem;
  GtkWidget *submenu;
  GMenuModel *m;
  gchar *label;

  n = g_menu_model_get_n_items (model);

  if (*need_separator && n > 0)
    {
      w = gtk_separator_menu_item_new ();
      gtk_widget_show (w);
      gtk_menu_shell_append (menu, w);
      *need_separator = FALSE;
    }

  if (heading != NULL)
    {
      w = gtk_menu_item_new_with_label (heading);
      gtk_widget_show (w);
      gtk_widget_set_sensitive (w, FALSE);
      gtk_menu_shell_append (GTK_MENU_SHELL (menu), w);
    }

  for (i = 0; i < n; i++)
    {
      if ((m = g_menu_model_get_item_link (model, i, G_MENU_LINK_SECTION)))
        {
          label = NULL;
          g_menu_model_get_item_attribute (model, i, G_MENU_ATTRIBUTE_LABEL, "s", &label);
          append_items_from_model (menu, m, actions, need_separator, label);
          g_object_unref (m);
          g_free (label);

          if (*need_separator)
            {
              w = gtk_separator_menu_item_new ();
              gtk_widget_show (w);
              gtk_menu_shell_append (menu, w);
              *need_separator = FALSE;
            }

          continue;
        }

      menuitem = gtk_model_menu_item_new (model, i, actions);

      if ((m = g_menu_model_get_item_link (model, i, G_MENU_LINK_SUBMENU)))
        {
          submenu = gtk_menu_new ();
          populate_menu_from_model (GTK_MENU_SHELL (submenu), m, actions);
          gtk_menu_item_set_submenu (menuitem, submenu);
          g_object_unref (m);
        }

      gtk_widget_show (GTK_WIDGET (menuitem));
      gtk_menu_shell_append (menu, GTK_WIDGET (menuitem));

      *need_separator = TRUE;
    }
}

static void
populate_menu_from_model (GtkMenuShell      *menu,
                          GMenuModel        *model,
                          GActionObservable *actions)
{
  gboolean need_separator;

  need_separator = FALSE;
  append_items_from_model (menu, model, actions, &need_separator, NULL);
}

typedef struct {
  GActionObservable *actions;
  GMenuModel        *model;
  GtkMenuShell      *menu;
  guint              update_idle;
  GHashTable        *connected;
} ItemsChangedData;

static void
free_items_changed_data (gpointer data)
{
  ItemsChangedData *d = data;

  g_object_unref (d->actions);
  g_object_unref (d->model);

  if (d->update_idle != 0)
    g_source_remove (d->update_idle);

  g_hash_table_unref (d->connected);

  g_free (d);
}

static gboolean
repopulate_menu (gpointer data)
{
  ItemsChangedData *d = data;
  GList *children, *l;
  GtkWidget *child;

  /* remove current children */
  children = gtk_container_get_children (GTK_CONTAINER (d->menu));
  for (l = children; l; l = l->next)
    {
      child = l->data;
      gtk_container_remove (GTK_CONTAINER (d->menu), child);
    }
  g_list_free (children);

  populate_menu_from_model (d->menu, d->model, d->actions);
  d->update_idle = 0;

  return FALSE;
}

static void
connect_to_items_changed (GMenuModel *model,
                          GCallback   callback,
                          gpointer    data)
{
  ItemsChangedData *d = data;
  gint i;
  GMenuModel *m;
  GMenuLinkIter *iter;

  if (!g_hash_table_lookup (d->connected, model))
    {
      g_signal_connect (model, "items-changed", callback, data);
      g_hash_table_insert (d->connected, model, model);
    }

  for (i = 0; i < g_menu_model_get_n_items (model); i++)
    {
      iter = g_menu_model_iterate_item_links (model, i);
      while (g_menu_link_iter_next (iter))
        {
          m = g_menu_link_iter_get_value (iter);
          connect_to_items_changed (m, callback, data);
          g_object_unref (m);
        }
      g_object_unref (iter);
    }
}

static void
items_changed (GMenuModel *model,
               gint        position,
               gint        removed,
               gint        added,
               gpointer    data)
{
  ItemsChangedData *d = data;

  if (d->update_idle == 0)
    d->update_idle = gdk_threads_add_idle (repopulate_menu, data);
  connect_to_items_changed (model, G_CALLBACK (items_changed), data);
}

static GtkWidget *
gtk_application_window_create_menubar (GMenuModel        *model,
                                       GActionObservable *actions)
{
  ItemsChangedData *data;
  GtkWidget *menubar;

  menubar = gtk_menu_bar_new ();

  data = g_new (ItemsChangedData, 1);
  data->model = g_object_ref (model);
  data->actions = g_object_ref (actions);
  data->menu = GTK_MENU_SHELL (menubar);
  data->update_idle = 0;
  data->connected = g_hash_table_new (NULL, NULL);

  g_object_set_data_full (G_OBJECT (menubar), "gtk-application-menu-data",
                          data, free_items_changed_data);

  connect_to_items_changed (model, G_CALLBACK (items_changed), data);
  repopulate_menu (data);

  return menubar;
}