/*
 * Copyright © 2016 Red Hat, Inc
 *
 * This program 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, see <http://www.gnu.org/licenses/>.
 *
 * Authors:
 *       Jonas Ådahl <jadahl@redhat.com>
 */

#include <errno.h>
#include <gdk/gdk.h>
#ifdef GDK_WINDOWING_X11
#include <gdk/x11/gdkx.h>
#include <X11/Xlib.h>
#endif
#include <stdlib.h>

#include "shew-external-window-x11.h"

static GdkDisplay *x11_display;

struct _ShewExternalWindowX11
{
  ShewExternalWindow parent;

  int foreign_xid;
};

G_DEFINE_TYPE (ShewExternalWindowX11, shew_external_window_x11,
               SHEW_TYPE_EXTERNAL_WINDOW)

static GdkDisplay *
get_x11_display (void)
{
  if (x11_display)
    return x11_display;

  gdk_set_allowed_backends ("x11");
  x11_display = gdk_display_open (NULL);
  gdk_set_allowed_backends (NULL);
  if (!x11_display)
    g_warning ("Failed to open X11 display");

  return x11_display;
}

static gboolean
check_foreign_xid (GdkDisplay *display,
                   int         xid)
{
  gboolean result = FALSE;
#ifdef GDK_WINDOWING_X11
  XWindowAttributes attrs;

  gdk_x11_display_error_trap_push (display);
  result = XGetWindowAttributes (GDK_DISPLAY_XDISPLAY (display), xid, &attrs);
  if (gdk_x11_display_error_trap_pop (display))
    return FALSE;

#endif
  return result;
}

ShewExternalWindowX11 *
shew_external_window_x11_new (const char *handle_str)
{
  ShewExternalWindowX11 *external_window_x11;
  GdkDisplay *display;
  int xid;

  display = get_x11_display ();
  if (!display)
    {
      g_warning ("No X display connection, ignoring X11 parent");
      return NULL;
    }

  errno = 0;
  xid = strtol (handle_str, NULL, 16);
  if (errno != 0)
    {
      g_warning ("Failed to reference external X11 window, invalid XID %s", handle_str);
      return NULL;
    }

  if (!check_foreign_xid (display, xid))
    {
      g_warning ("Failed to find foreign window for XID %d", xid);
      return NULL;
    }

  external_window_x11 = g_object_new (SHEW_TYPE_EXTERNAL_WINDOW_X11,
                                      "display", display,
                                      NULL);
  external_window_x11->foreign_xid = xid;

  return external_window_x11;
}

static void
shew_external_window_x11_set_parent_of (ShewExternalWindow *external_window,
                                        GdkSurface         *child_surface)
{
  ShewExternalWindowX11 *external_window_x11 =
    SHEW_EXTERNAL_WINDOW_X11 (external_window);

#ifdef GDK_WINDOWING_X11
  XSetTransientForHint (GDK_SURFACE_XDISPLAY (child_surface),
                        GDK_SURFACE_XID (child_surface),
                        external_window_x11->foreign_xid);
#endif
}

static void
shew_external_window_x11_init (ShewExternalWindowX11 *external_window_x11)
{
}

static void
shew_external_window_x11_class_init (ShewExternalWindowX11Class *klass)
{
  ShewExternalWindowClass *external_window_class = SHEW_EXTERNAL_WINDOW_CLASS (klass);

  external_window_class->set_parent_of = shew_external_window_x11_set_parent_of;
}