/* xscreensaver-command, Copyright (c) 1991-2020 Jamie Zawinski <jwz@jwz.org>
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation.  No representations are made about the suitability of this
 * software for any purpose.  It is provided "as is" without express or 
 * implied warranty.
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <sys/time.h>
#include <sys/types.h>

#ifdef HAVE_SYS_SELECT_H
# include <sys/select.h>
#endif /* HAVE_SYS_SELECT_H */

#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif

#include <X11/Xproto.h>		/* for CARD32 */
#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/Xutil.h>		/* for XGetClassHint() */
#include <X11/Xos.h>

#include "remote.h"

#ifdef _VROOT_H_
ERROR! you must not include vroot.h in this file
#endif

extern char *progname;
extern Atom XA_SCREENSAVER, XA_SCREENSAVER_VERSION, XA_SCREENSAVER_RESPONSE;
extern Atom XA_SCREENSAVER_ID, XA_SCREENSAVER_STATUS, XA_EXIT;
extern Atom XA_VROOT, XA_SELECT, XA_DEMO, XA_BLANK, XA_LOCK;
extern Atom XA_ACTIVATE, XA_SUSPEND, XA_NEXT, XA_PREV, XA_EXIT;


static XErrorHandler old_handler = 0;
static Bool got_badwindow = False;
static int
BadWindow_ehandler (Display *dpy, XErrorEvent *error)
{
  if (error->error_code == BadWindow)
    {
      got_badwindow = True;
      return 0;
    }
  else
    {
      fprintf (stderr, "%s: ", progname);
      if (!old_handler) abort();
      return (*old_handler) (dpy, error);
    }
}



static Window
find_screensaver_window (Display *dpy, char **version)
{
  int i;
  Window root = RootWindowOfScreen (DefaultScreenOfDisplay (dpy));
  Window root2, parent, *kids;
  unsigned int nkids;

  if (version) *version = 0;

  if (! XQueryTree (dpy, root, &root2, &parent, &kids, &nkids))
    abort ();
  if (root != root2)
    abort ();
  if (parent)
    abort ();
  if (! (kids && nkids))
    return 0;
  for (i = 0; i < nkids; i++)
    {
      Atom type;
      int format;
      unsigned long nitems, bytesafter;
      unsigned char *v;
      int status;

      /* We're walking the list of root-level windows and trying to find
         the one that has a particular property on it.  We need to trap
         BadWindows errors while doing this, because it's possible that
         some random window might get deleted in the meantime.  (That
         window won't have been the one we're looking for.)
       */
      XSync (dpy, False);
      if (old_handler) abort();
      got_badwindow = False;
      old_handler = XSetErrorHandler (BadWindow_ehandler);
      status = XGetWindowProperty (dpy, kids[i],
                                   XA_SCREENSAVER_VERSION,
                                   0, 200, False, XA_STRING,
                                   &type, &format, &nitems, &bytesafter,
                                   &v);
      XSync (dpy, False);
      XSetErrorHandler (old_handler);
      old_handler = 0;

      if (got_badwindow)
        {
          status = BadWindow;
          got_badwindow = False;
        }

      if (status == Success && type != None)
	{
          Window ret = kids[i];
	  if (version)
	    *version = (char *) v;
          XFree (kids);
	  return ret;
	}
    }

  if (kids) XFree (kids);
  return 0;
}


static int
send_xscreensaver_command (Display *dpy, Atom command, long arg,
			   Window *window_ret, char **error_ret)
{
  int status = -1;
  char *v = 0;
  Window window = find_screensaver_window (dpy, &v);
  XWindowAttributes xgwa;
  char err[2048];

  if (window_ret)
    *window_ret = window;

  if (!window)
    {
      sprintf (err, "no screensaver is running on display %s",
               DisplayString (dpy));

      if (error_ret)
        {
          *error_ret = strdup (err);
          status = -1;
          goto DONE;
        }

      if (command == XA_EXIT)
        {
          /* Don't print an error if xscreensaver is already dead. */
          status = 1;
          goto DONE;
        }

      fprintf (stderr, "%s: %s\n", progname, err);
      status = -1;
      goto DONE;
    }

  /* Select for property change events, so that we can read the response. */
  XGetWindowAttributes (dpy, window, &xgwa);
  XSelectInput (dpy, window, xgwa.your_event_mask | PropertyChangeMask);

  if (command == XA_SCREENSAVER_STATUS ||
      command == XA_SCREENSAVER_VERSION)
    {
      XClassHint hint;
      memset (&hint, 0, sizeof(hint));
      if (!v || !*v)
	{
	  sprintf (err, "version property not set on window 0x%x?",
		   (unsigned int) window);
          if (error_ret)
            *error_ret = strdup (err);
          else
            fprintf (stderr, "%s: %s\n", progname, err);

          status = -1;
          goto DONE;
	}

      XGetClassHint(dpy, window, &hint);
      if (!hint.res_class)
	{
	  sprintf (err, "class hints not set on window 0x%x?",
		   (unsigned int) window);
          if (error_ret)
            *error_ret = strdup (err);
          else
            fprintf (stderr, "%s: %s\n", progname, err);

          status = -1;
          goto DONE;
	}

      fprintf (stdout, "%s %s", hint.res_class, v);

      if (command != XA_SCREENSAVER_STATUS)
	{
	  fprintf (stdout, "\n");
	}
      else
	{
	  Atom type;
	  int format;
	  unsigned long nitems, bytesafter;
	  unsigned char *dataP = 0;

	  if (XGetWindowProperty (dpy,
                                  RootWindow (dpy, 0),
				  XA_SCREENSAVER_STATUS,
				  0, 999, False, XA_INTEGER,
				  &type, &format, &nitems, &bytesafter,
				  &dataP)
	      == Success
	      && type
	      && dataP)
	    {
              Atom blanked;
              time_t tt;
              char *s;
              Atom *data = (Atom *) dataP;

              if (type != XA_INTEGER || nitems < 3)
                {
                STATUS_LOSE:
                  if (data) free (data);
                  fprintf (stdout, "\n");
                  fflush (stdout);
                  fprintf (stderr, "bad status format on root window.\n");
                  status = -1;
                  goto DONE;
                }
                  
              blanked = (Atom) data[0];
              tt = (time_t) data[1];

              if (tt <= (time_t) 666000000L) /* early 1991 */
                goto STATUS_LOSE;

	      if (blanked == XA_BLANK)
		fputs (": screen blanked since ", stdout);
	      else if (blanked == XA_LOCK)
		fputs (": screen locked since ", stdout);
	      else if (blanked == 0)
		/* suggestions for a better way to phrase this are welcome. */
		fputs (": screen non-blanked since ", stdout);
              else
                /* `blanked' has an unknown value - fail. */
                goto STATUS_LOSE;

              s = ctime(&tt);
              if (s[strlen(s)-1] == '\n')
                s[strlen(s)-1] = 0;
              fputs (s, stdout);

              {
                int nhacks = nitems - 2;
                Bool any = False;
                int i;
                for (i = 0; i < nhacks; i++)
                  if (data[i + 2] > 0)
                    {
                      any = True;
                      break;
                    }

                if (any && nhacks == 1)
                  fprintf (stdout, " (hack #%d)\n", (int) data[2]);
                else if (any)
                  {
                    fprintf (stdout, " (hacks: ");
                    for (i = 0; i < nhacks; i++)
                      {
                        fprintf (stdout, "#%d", (int) data[2 + i]);
                        if (i != nhacks-1)
                          fputs (", ", stdout);
                      }
                    fputs (")\n", stdout);
                  }
                else
                  fputs ("\n", stdout);
              }

	      if (data) free (data);
	    }
	  else
	    {
	      if (dataP) XFree (dataP);
	      fprintf (stdout, "\n");
	      fflush (stdout);
	      fprintf (stderr, "no saver status on root window.\n");
              status = -1;
              goto DONE;
	    }
	}

      /* No need to read a response for these commands. */
      status = 1;
      goto DONE;
    }
  else
    {
      XEvent event;
      long arg1 = arg;
      long arg2 = 0;

      if (arg < 0)
	abort();
      else if (arg == 0 && command == XA_SELECT)
	abort();
      else if (arg != 0 && command == XA_DEMO)
	{
	  arg1 = 5000;	/* version number of the XA_DEMO protocol, */
	  arg2 = arg;	/* since it didn't use to take an argument. */
	}

      event.xany.type = ClientMessage;
      event.xclient.display = dpy;
      event.xclient.window = window;
      event.xclient.message_type = XA_SCREENSAVER;
      event.xclient.format = 32;
      memset (&event.xclient.data, 0, sizeof(event.xclient.data));
      event.xclient.data.l[0] = (long) command;
      event.xclient.data.l[1] = arg1;
      event.xclient.data.l[2] = arg2;
      if (! XSendEvent (dpy, window, False, 0L, &event))
	{
	  sprintf (err, "XSendEvent(dpy, 0x%x ...) failed.\n",
		   (unsigned int) window);
          if (error_ret)
            *error_ret = strdup (err);
          else
            fprintf (stderr, "%s: %s\n", progname, err);
          status = -1;
          goto DONE;
	}
    }

  status = 0;

 DONE:
  if (v) free (v);
  XSync (dpy, 0);
  return status;
}


static Bool
xscreensaver_command_event_p (Display *dpy, XEvent *event, XPointer arg)
{
  return (event->xany.type == PropertyNotify &&
          event->xproperty.state == PropertyNewValue &&
          event->xproperty.atom == XA_SCREENSAVER_RESPONSE);
}


static int
xscreensaver_command_response (Display *dpy, Window window,
                               Bool verbose_p, Bool exiting_p,
                               char **error_ret)
{
  int sleep_count = 0;
  char err[2048];
  XEvent event;
  Bool got_event = False;

  while (!(got_event = XCheckIfEvent(dpy, &event,
				     &xscreensaver_command_event_p, 0)) &&
	 sleep_count++ < 10)
    {
# if defined(HAVE_SELECT)
      /* Wait for an event, but don't wait longer than 1 sec.  Note that we
         might do this multiple times if an event comes in, but it wasn't
         the event we're waiting for.
       */
      int fd = XConnectionNumber(dpy);
      fd_set rset;
      struct timeval tv;
      tv.tv_sec  = 1;
      tv.tv_usec = 0;
      FD_ZERO (&rset);
      FD_SET (fd, &rset);
      select (fd+1, &rset, 0, 0, &tv);
# else  /* !HAVE_SELECT */
      sleep(1);
# endif /* !HAVE_SELECT */
    }

  if (!got_event)
    {
      sprintf (err, "no response to command.");
      if (error_ret)
	*error_ret = strdup (err);
      else
	fprintf (stderr, "%s: %s\n", progname, err);

      return -1;
    }
  else
    {
      Status st2;
      Atom type;
      int format;
      unsigned long nitems, bytesafter;
      unsigned char *msg = 0;

      XSync (dpy, False);
      if (old_handler) abort();
      old_handler = XSetErrorHandler (BadWindow_ehandler);
      st2 = XGetWindowProperty (dpy, window,
				XA_SCREENSAVER_RESPONSE,
				0, 1024, True,
				AnyPropertyType,
				&type, &format, &nitems, &bytesafter,
				&msg);
      XSync (dpy, False);
      XSetErrorHandler (old_handler);
      old_handler = 0;

      if (got_badwindow)
	{
	  if (exiting_p)
	    return 0;

	  sprintf (err, "xscreensaver window unexpectedly deleted.");

	  if (error_ret)
	    *error_ret = strdup (err);
	  else
	    fprintf (stderr, "%s: %s\n", progname, err);

	  return -1;
	}

      if (st2 == Success && type != None)
	{
	  if (type != XA_STRING || format != 8)
	    {
	      sprintf (err, "unrecognized response property.");

	      if (error_ret)
		*error_ret = strdup (err);
	      else
		fprintf (stderr, "%s: %s\n", progname, err);

	      if (msg) XFree (msg);
	      return -1;
	    }
	  else if (!msg || (msg[0] != '+' && msg[0] != '-'))
	    {
	      sprintf (err, "unrecognized response message.");

	      if (error_ret)
		*error_ret = strdup (err);
	      else  
		fprintf (stderr, "%s: %s\n", progname, err);

	      if (msg) XFree (msg);
	      return -1;
	    }
	  else
	    {
	      int ret = (msg[0] == '+' ? 0 : -1);
	      sprintf (err, "%s: %s\n", progname, (char *) msg+1);

	      if (error_ret)
		*error_ret = strdup (err);
	      else if (verbose_p || ret != 0)
		fprintf ((ret < 0 ? stderr : stdout), "%s\n", err);

	      XFree (msg);
	      return ret;
	    }
	}
    }

  return -1;  /* warning suppression: not actually reached */
}


/* Wait until the window has been mapped, blanking the screen.
   Catches errors, times out after a few seconds.
 */
static int
xscreensaver_command_wait_for_blank (Display *dpy, Window window,
                                     Bool verbose_p, char **error_ret)
{
  time_t start = time((time_t*)0);
  int max = 10;
  char err[2048];
  Status status = -1;

  while (1)
    {
      XWindowAttributes xgwa;
      xgwa.map_state = IsUnmapped;

      if (!window)
        got_badwindow = True;
      else
        {
          XSync (dpy, False);
          if (old_handler) abort();
          got_badwindow = False;
          old_handler = XSetErrorHandler (BadWindow_ehandler);
          status = XGetWindowAttributes (dpy, window, &xgwa);
          XSync (dpy, False);
          XSetErrorHandler (old_handler);
          old_handler = 0;
        }

      if (got_badwindow)
        {
          /* If we got a BadWindow, it might be that in the course of
             activating, xscreensaver had to destroy and re-create the
             window to get one with the proper Visual. So wait for a
             new window to come into existence.
           */
          if (window && verbose_p > 1)
            fprintf (stderr,
                     "%s: BadWindow 0x%08x waiting for screen to blank\n",
                     progname, (unsigned int) window);
          window = find_screensaver_window (dpy, 0);
          if (window && verbose_p > 1)
            fprintf (stderr, "%s: new window is 0x%08x.\n",
                     progname, (unsigned int) window);
          got_badwindow = False;
        }
      else if (status == 0)
        {
          sprintf (err, "error on 0x%08x waiting for screen to blank",
                   (unsigned int) window);
          if (error_ret)
            *error_ret = strdup (err);
          else
            fprintf (stderr, "%s: %s\n", progname, err);
          return -1;
        }
      else if (xgwa.map_state == IsViewable)
        {
          if (verbose_p > 1)
            fprintf (stderr, "%s: window 0x%08x mapped.\n",
                     progname, (unsigned int) window);
          return 0;
        }
      else
        {
          time_t now = time((time_t*)0);

          if (now >= start + max)
            {
              sprintf (err, "Timed out waiting for screen to blank on 0x%08x",
                       (unsigned int) window);
              if (error_ret)
                *error_ret = strdup (err);
              else
                fprintf (stderr, "%s: %s\n", progname, err);
              return -1;
            }
          else if (verbose_p && now > start + 3)
            {
              fprintf (stderr, "%s: waiting for window 0x%08x to map\n",
                       progname, (unsigned int) window);
              verbose_p++;
            }
        }

# if defined(HAVE_SELECT)
      {
        struct timeval tv;
        tv.tv_sec  = 0;
        tv.tv_usec = 1000000L / 10;
        select (0, 0, 0, 0, &tv);
      }
# else
      sleep (1);
# endif
    }

  return 0;
}



int
xscreensaver_command (Display *dpy, Atom command, long arg, Bool verbose_p,
                      char **error_ret)
{
  Window w = 0;
  int status = send_xscreensaver_command (dpy, command, arg, &w, error_ret);
  if (status == 0)
    status = xscreensaver_command_response (dpy, w, verbose_p,
                                            (command == XA_EXIT),
                                            error_ret);

  /* If this command should result in the screen being blank, wait until
     the xscreensaver window is mapped before returning. */
  if (status == 0 &&
      (command == XA_ACTIVATE ||
       command == XA_SUSPEND ||
       command == XA_LOCK ||
       command == XA_NEXT ||
       command == XA_PREV ||
       command == XA_SELECT))
    status = xscreensaver_command_wait_for_blank (dpy, w, verbose_p,
                                                  error_ret);

  fflush (stdout);
  fflush (stderr);
  return (status < 0 ? status : 0);
}


void
server_xscreensaver_version (Display *dpy,
			     char **version_ret,
			     char **user_ret,
			     char **host_ret)
{
  Window window = find_screensaver_window (dpy, 0);

  Atom type;
  int format;
  unsigned long nitems, bytesafter;

  if (version_ret)
    *version_ret = 0;
  if (user_ret)
    *user_ret = 0;
  if (host_ret)
    *host_ret = 0;

  if (!window)
    return;

  if (version_ret)
    {
      unsigned char *v = 0;
      XGetWindowProperty (dpy, window, XA_SCREENSAVER_VERSION, 0, 1,
			  False, XA_STRING, &type, &format, &nitems,
			  &bytesafter, &v);
      if (v)
	{
	  *version_ret = strdup ((char *) v);
	  XFree (v);
	}
    }

  if (user_ret || host_ret)
    {
      unsigned char *id = 0;
      const char *user = 0;
      const char *host = 0;

      XGetWindowProperty (dpy, window, XA_SCREENSAVER_ID, 0, 512,
			  False, XA_STRING, &type, &format, &nitems,
			  &bytesafter, &id);
      if (id && *id)
	{
	  const char *old_tag = " on host ";
	  const char *s = strstr ((char *) id, old_tag);
	  if (s)
	    {
	      /* found ID of the form "1234 on host xyz". */
	      user = 0;
	      host = s + strlen (old_tag);
	    }
	  else
	    {
	      char *o = 0, *p = 0, *c = 0;
	      o = strchr ((char *) id, '(');
	      if (o) p = strrchr (o, '@');
	      if (p) c = strchr (p, ')');
	      if (c)
		{
		  /* found ID of the form "1234 (user@host)"
                     or the weirder "1234 (user@crap@host)". */
		  user = o+1;
		  host = p+1;
		  *p = 0;
		  *c = 0;
		}
	    }

	}

      if (user && *user && *user != '?')
	*user_ret = strdup (user);
      else
	*user_ret = 0;

      if (host && *host && *host != '?')
	*host_ret = strdup (host);
      else
	*host_ret = 0;

      if (id)
	XFree (id);
    }
}
