/*
 * gcc -o kill-weston -g -O0 kill-weston.c `pkg-config --libs --cflags gtk+-3.0`
 */

#include <gtk/gtk.h>

static void
destroy (GtkWidget *widget, 
         gpointer data)
{
    gtk_main_quit ();
}

static gboolean
popup_grab_on_window (GdkWindow *window,
                      GdkDevice *keyboard,
                      GdkDevice *pointer,
                      guint32    activate_time)
{
    if (keyboard &&
        gdk_device_grab (keyboard, window,
                         GDK_OWNERSHIP_WINDOW, TRUE,
                         GDK_KEY_PRESS_MASK |
                         GDK_KEY_RELEASE_MASK,
                         NULL, activate_time) != GDK_GRAB_SUCCESS)
      {
        return FALSE;
      }

    if (pointer &&
        gdk_device_grab (pointer, window,
                         GDK_OWNERSHIP_WINDOW, TRUE,
                         GDK_SMOOTH_SCROLL_MASK |
                         GDK_BUTTON_PRESS_MASK |
                         GDK_BUTTON_RELEASE_MASK |
                         GDK_ENTER_NOTIFY_MASK |
                         GDK_LEAVE_NOTIFY_MASK |
                         GDK_POINTER_MOTION_MASK,
                         NULL, activate_time) != GDK_GRAB_SUCCESS)
      {
        if (keyboard)
          gdk_device_ungrab (keyboard, activate_time);

        return FALSE;
      }

    return TRUE;
}

static GdkDevice *
grab_device (GtkWidget *widget)
{
    GdkDevice *keyboard, *pointer, *device;
    GdkDisplay *display;

    display = gtk_widget_get_display (widget);
    device = gtk_get_current_event_device ();
    if (device && gdk_device_get_display (device) != display)
      device = NULL;

    if (device == NULL)
      {
        GdkDeviceManager *device_manager;
        GList *devices;

        device_manager = gdk_display_get_device_manager (display);
        devices = gdk_device_manager_list_devices (device_manager,
                                                   GDK_DEVICE_TYPE_MASTER);

        device = devices->data;
        g_list_free (devices);
      }

    if (gdk_device_get_source (device) == GDK_SOURCE_KEYBOARD)
      {
        keyboard = device;
        pointer = gdk_device_get_associated_device (device);
      }
    else
      {
        pointer = device;
        keyboard = gdk_device_get_associated_device (device);
      }

    if (popup_grab_on_window (gtk_widget_get_window (widget),
            keyboard, pointer, gtk_get_current_event_time ()))
        return pointer;
    else
        g_warning ("Failed to grab device!");

    return NULL;
}

static void
ungrab_device (GdkDevice *pointer)
{
    GdkDevice *keyboard;

    gdk_device_ungrab (pointer, GDK_CURRENT_TIME);
    keyboard = gdk_device_get_associated_device (pointer);

    if (keyboard)
        gdk_device_ungrab (keyboard, GDK_CURRENT_TIME);
}

static void
show_popup (GtkWidget *parent)
{
    GtkWidget *popup;
    GdkDevice *pointer;

    gtk_widget_realize (parent);
    popup = gtk_window_new (GTK_WINDOW_POPUP);

    gtk_window_group_add_window (gtk_window_get_group (GTK_WINDOW (parent)),
                                 GTK_WINDOW (popup));
    gtk_window_set_transient_for (GTK_WINDOW (popup), GTK_WINDOW (parent));

    gtk_widget_realize (popup);
    gtk_window_set_type_hint (GTK_WINDOW (popup), GDK_WINDOW_TYPE_HINT_POPUP_MENU);
    pointer = grab_device (GTK_WIDGET (popup));
    if (pointer)
      gtk_device_grab_add (GTK_WIDGET (popup), pointer, TRUE);

    gtk_window_move (GTK_WINDOW (popup), 200, 200);
    gtk_window_resize (GTK_WINDOW (popup), 25, 25);
    gtk_widget_show (GTK_WIDGET (popup));

    if (pointer)
      {
        ungrab_device (pointer);
        gtk_device_grab_remove (GTK_WIDGET (popup), pointer);
      }
}

int
main (int   argc, 
      char *argv[])
{
    GtkWidget *window;

    gtk_init (&argc, &argv);

    /* create a new window */
    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);

    gtk_window_resize (GTK_WINDOW (window), 200, 200);

    g_signal_connect (window, "destroy", G_CALLBACK (destroy), NULL);
    show_popup (window);
    gtk_widget_show_all (GTK_WIDGET (window));

    gtk_main ();

    return 0;
}