/*
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/MPL/
 * 
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 * 
 * The Original Code is mozilla.org code.
 * 
 * The Initial Developers of the Original Code are Christopher
 * Blizzard and Jamie Zawinski.  Portions created Christopher Blizzard
 * are Copyright (C) 2000 Christopher Blizzard.  Portions created by
 * Jamie Zawinski are Copyright (C) 1994 Netscape Communications
 * Corporation.  All Rights Reserved.
 * 
 * Contributor(s): 
 */

#define NS_XREMOTECLIENT_CID                        \
{ 0xcfae5900,                                        \
  0x1dd1,                                            \
  0x11b2,                                            \
  { 0x95, 0xd0, 0xad, 0x45, 0x4c, 0x23, 0x3d, 0xc6 } \
}

/* cfae5900-1dd1-11b2-95d0-ad454c233dc6 */

#include "nsIGenericFactory.h"
#include "XRemoteClient.h"
#include "prmem.h"
#include "prprf.h"
#include "plstr.h"
#include "prsystem.h"
#include "prlog.h"
#include "prenv.h"
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <X11/Xatom.h>
#ifdef POLL_WITH_XCONNECTIONNUMBER
#include <poll.h>
#endif

#define MOZILLA_VERSION_PROP   "_MOZILLA_VERSION"
#define MOZILLA_LOCK_PROP      "_MOZILLA_LOCK"
#define MOZILLA_COMMAND_PROP   "_MOZILLA_COMMAND"
#define MOZILLA_RESPONSE_PROP  "_MOZILLA_RESPONSE"
#define MOZILLA_USER_PROP      "_MOZILLA_USER"

static PRLogModuleInfo *sRemoteLm = NULL;

XRemoteClient::XRemoteClient()
{
  NS_INIT_ISUPPORTS();
  mDisplay = 0;
  mInitialized = PR_FALSE;
  mMozVersionAtom = 0;
  mMozLockAtom = 0;
  mMozCommandAtom = 0;
  mMozResponseAtom = 0;
  mMozWMStateAtom = 0;
  mMozUserAtom = 0;
  if (!sRemoteLm)
    sRemoteLm = PR_NewLogModule("XRemoteClient");
  PR_LOG(sRemoteLm, PR_LOG_DEBUG, ("XRemoteClient::XRemoteClient"));
}

XRemoteClient::~XRemoteClient()
{
  PR_LOG(sRemoteLm, PR_LOG_DEBUG, ("XRemoteClient::~XRemoteClient"));
  if (mInitialized)
    Shutdown();
}

NS_IMPL_ISUPPORTS1(XRemoteClient, nsIXRemoteClient);

NS_IMETHODIMP
XRemoteClient::Init (void)
{
  PR_LOG(sRemoteLm, PR_LOG_DEBUG, ("XRemoteClient::Init"));

  if (mInitialized)
    return NS_OK;
  // try to open the display
  mDisplay = XOpenDisplay(0);
  if (!mDisplay)
    return NS_ERROR_FAILURE;

  // get our atoms
  mMozVersionAtom  = XInternAtom(mDisplay, MOZILLA_VERSION_PROP, False);
  mMozLockAtom     = XInternAtom(mDisplay, MOZILLA_LOCK_PROP, False);
  mMozCommandAtom  = XInternAtom(mDisplay, MOZILLA_COMMAND_PROP, False);
  mMozResponseAtom = XInternAtom(mDisplay, MOZILLA_RESPONSE_PROP, False);
  mMozWMStateAtom  = XInternAtom(mDisplay, "WM_STATE", False);
  mMozUserAtom      = XInternAtom(mDisplay, MOZILLA_USER_PROP, False);

  mInitialized = PR_TRUE;

  return NS_OK;
}

NS_IMETHODIMP
XRemoteClient::SendCommand (const char *aCommand, PRBool *aWindowFound)
{
  PR_LOG(sRemoteLm, PR_LOG_DEBUG, ("XRemoteClient::SendCommand"));

  *aWindowFound = PR_TRUE;

  // find the remote window
  Window window = FindWindow();

  // no window?  let the caller know.
  if (!window) {
    *aWindowFound = PR_FALSE;
    return NS_OK;
  }

  // make sure we get the right events on that window
  XSelectInput(mDisplay, window,
	       (PropertyChangeMask|StructureNotifyMask));
  
  nsresult rv;
  PRBool destroyed = PR_FALSE;

  // get the lock on the window
  rv = GetLock(window, &destroyed);

  if (NS_FAILED(rv))
    return NS_ERROR_FAILURE;

  // send our command
  rv = DoSendCommand(window, aCommand, &destroyed);

  // if the window was destroyed, don't bother trying to free the
  // lock.
  if (destroyed)
    return NS_ERROR_FAILURE;

  // doesn't really matter what this returns
  FreeLock(window);

  // if we failed above we had to free the lock - return the error
  // now.
  if (NS_FAILED(rv))
    return NS_ERROR_FAILURE;

  return NS_OK;
}

NS_IMETHODIMP
XRemoteClient::Shutdown (void)
{
  PR_LOG(sRemoteLm, PR_LOG_DEBUG, ("XRemoteClient::Shutdown"));

  if (!mInitialized)
    return NS_OK;
  // shut everything down
  XCloseDisplay(mDisplay);
  mDisplay = 0;
  mInitialized = PR_FALSE;
  return NS_OK;
}

Window
XRemoteClient::FindWindow(void)
{
  Window root = RootWindowOfScreen(DefaultScreenOfDisplay(mDisplay));
  Window root2, parent, *kids;
  unsigned int nkids;
  Window result = 0;
  int i;
  
  if (!XQueryTree(mDisplay, root, &root2, &parent, &kids, &nkids)) {
    PR_LOG(sRemoteLm, PR_LOG_DEBUG,
	   ("XQueryTree failed in XRemoteClient::FindWindow"));
    return 0;
  }

  if (!(kids && nkids)) {
    PR_LOG(sRemoteLm, PR_LOG_DEBUG, ("root window has no children"));
    return 0;
  }

  for (i=nkids-1; i >= 0; i--) {
    Atom type;
    int format;
    unsigned long nitems, bytesafter;
    unsigned char *data_return = 0;
    Window w;
    w = kids[i];
    // find the inner window with WM_STATE on it
    w = CheckWindow(w);

    int status = XGetWindowProperty(mDisplay, w, mMozVersionAtom,
				    0, (65536 / sizeof (long)),
				    False, XA_STRING,
				    &type, &format, &nitems, &bytesafter,
				    &data_return);

    if (!data_return)
      continue;

    XFree(data_return);
    data_return = 0;

    if (status == Success && type != None) {
      // Check to see if it has the user atom on that window.  If there
      // is then we need to make sure that it matches what we have.
      char *logname;
      logname = PR_GetEnv("LOGNAME");

      if (logname) {
	status = XGetWindowProperty(mDisplay, w, mMozUserAtom,
				    0, (65536 / sizeof(long)),
				    False, XA_STRING,
				    &type, &format, &nitems, &bytesafter,
				    &data_return);

	// if there's a username compare it with what we have
	if (data_return) {

	  // if the IDs are equal then this is the window we want.  if
	  // they aren't fall through to the next loop iteration.
	  if (!strcmp(logname, (const char *)data_return)) {
	    XFree(data_return);
	    result = w;
	    break;
	  }

	  XFree(data_return);
	}
      }

      // ok, this is the one we want since there's no username attribute on
      // it.
      else {
	result = w;
	break;
      }
    }
  }

  PR_LOG(sRemoteLm, PR_LOG_DEBUG, ("FindWindow returning 0x%lx\n", result));

  return result;
}

Window
XRemoteClient::CheckWindow(Window aWindow)
{
  Atom type = None;
  int  format;
  unsigned long nitems, bytesafter;
  unsigned char *data;
  Window innerWindow;

  XGetWindowProperty(mDisplay, aWindow, mMozWMStateAtom,
		     0, 0, False, AnyPropertyType,
		     &type, &format, &nitems, &bytesafter, &data);

  if (type)
    return aWindow;

  // didn't find it here so check the children of this window
  innerWindow = CheckChildren(aWindow);

  if (innerWindow)
    return innerWindow;

  return aWindow;
}

Window
XRemoteClient::CheckChildren(Window aWindow)
{
  Window root, parent;
  Window *children;
  unsigned int nchildren;
  unsigned int i;
  Atom type = None;
  int format;
  unsigned long nitems, after;
  unsigned char *data;
  Window retval = None;
  
  if (!XQueryTree(mDisplay, aWindow, &root, &parent, &children,
		  &nchildren))
    return None;
  
  // scan the list first before recursing into the list of windows
  // which can get quite deep.
  for (i=0; !retval && (i < nchildren); i++) {
    XGetWindowProperty(mDisplay, children[i], mMozWMStateAtom,
		       0, 0, False, AnyPropertyType, &type, &format,
		       &nitems, &after, &data);
    if (type)
      retval = children[i];
  }

  // otherwise recurse into the list
  for (i=0; !retval && (i < nchildren); i++) {
    retval = CheckChildren(children[i]);
  }

  if (children)
    XFree((char *)children);

  return retval;
}

nsresult
XRemoteClient::GetLock(Window aWindow, PRBool *aDestroyed)
{
  PRBool locked = PR_FALSE;
  PRBool waited = PR_FALSE;
  *aDestroyed = PR_FALSE;

  if (mLockData.Length() == 0) {
    
    char pidstr[256];
    char  sysinfobuf[SYS_INFO_BUFFER_LENGTH];
    PR_snprintf(pidstr, 255, "pid%d@", getpid());
    PRStatus status;
    status = PR_GetSystemInfo(PR_SI_HOSTNAME, sysinfobuf,
			      SYS_INFO_BUFFER_LENGTH);
    if (status != PR_SUCCESS) {
      NS_WARNING("failed to get hostname");
      return NS_ERROR_FAILURE;
    }
    mLockData.Append(pidstr);
    mLockData.Append(sysinfobuf);
  }

  do {
    int result;
    Atom actual_type;
    int actual_format;
    unsigned long nitems, bytes_after;
    unsigned char *data = 0;

    XGrabServer(mDisplay);

    result = XGetWindowProperty (mDisplay, aWindow, mMozLockAtom,
				 0, (65536 / sizeof (long)),
				 False, /* don't delete */
				 XA_STRING,
				 &actual_type, &actual_format,
				 &nitems, &bytes_after,
				 &data);
    if (result != Success || actual_type == None) {
      /* It's not now locked - lock it. */
      XChangeProperty (mDisplay, aWindow, mMozLockAtom, XA_STRING, 8,
		       PropModeReplace,
		       (unsigned char *) mLockData.get(),
		       strlen (mLockData));
      locked = True;
    }

    XUngrabServer(mDisplay);
    XSync(mDisplay, False);

    if (!locked) {
      /* We tried to grab the lock this time, and failed because someone
	 else is holding it already.  So, wait for a PropertyDelete event
	 to come in, and try again. */
      PR_LOG(sRemoteLm, PR_LOG_DEBUG, 
	     ("window 0x%x is locked by %s; waiting...\n",
	      (unsigned int) aWindow, data));
      waited = True;
      while (1) {
	XEvent event;
	int select_retval;
#ifdef POLL_WITH_XCONNECTIONNUMBER
       struct pollfd fds[1];
       fds[0].fd = XConnectionNumber(mDisplay);
       fds[0].events = POLLIN;
       select_retval = poll(fds,1,10*1000);
#else
	fd_set select_set;
	struct timeval delay;
	delay.tv_sec = 10;
	delay.tv_usec = 0;

	FD_ZERO(&select_set);
	// add the x event queue to the select set
	FD_SET(ConnectionNumber(mDisplay), &select_set);
	select_retval = select(ConnectionNumber(mDisplay) + 1,
			       &select_set, NULL, NULL, &delay);
#endif
	// did we time out?
	if (select_retval == 0) {
	  PR_LOG(sRemoteLm, PR_LOG_DEBUG, ("timed out waiting for window\n"));
	  return NS_ERROR_FAILURE;
	}
	PR_LOG(sRemoteLm, PR_LOG_DEBUG, ("xevent...\n"));
	XNextEvent (mDisplay, &event);
	if (event.xany.type == DestroyNotify &&
	    event.xdestroywindow.window == aWindow) {
	  PR_LOG(sRemoteLm, PR_LOG_DEBUG,
		 ("window 0x%x unexpectedly destroyed.\n",
		  (unsigned int) aWindow));
	  *aDestroyed = PR_TRUE;
	  return NS_ERROR_FAILURE;
	}
	else if (event.xany.type == PropertyNotify &&
		 event.xproperty.state == PropertyDelete &&
		 event.xproperty.window == aWindow &&
		 event.xproperty.atom == mMozLockAtom) {
	  /* Ok!  Someone deleted their lock, so now we can try
	     again. */
	  PR_LOG(sRemoteLm, PR_LOG_DEBUG,
		 ("(0x%x unlocked, trying again...)\n",
		  (unsigned int) aWindow));
		  break;
	}
      }
    }
    if (data)
      XFree(data);
  } while (!locked);

  if (waited) {
    PR_LOG(sRemoteLm, PR_LOG_DEBUG, ("obtained lock.\n"));
  }

  return NS_OK;
}

nsresult
XRemoteClient::FreeLock(Window aWindow)
{
  int result;
  Atom actual_type;
  int actual_format;
  unsigned long nitems, bytes_after;
  unsigned char *data = 0;

  result = XGetWindowProperty(mDisplay, aWindow, mMozLockAtom,
			      0, (65536 / sizeof(long)),
			      True, /* atomic delete after */
			      XA_STRING,
			      &actual_type, &actual_format,
			      &nitems, &bytes_after,
			      &data);
  if (result != Success) {
    PR_LOG(sRemoteLm, PR_LOG_DEBUG,
	   ("unable to read and delete " MOZILLA_LOCK_PROP
	    " property\n"));
    return NS_ERROR_FAILURE;
  }
  else if (!data || !*data){
    PR_LOG(sRemoteLm, PR_LOG_DEBUG,
	   ("invalid data on " MOZILLA_LOCK_PROP
	    " of window 0x%x.\n",
	    (unsigned int) aWindow));
    return NS_ERROR_FAILURE;
  }
  else if (strcmp((char *)data, mLockData)) {
  PR_LOG(sRemoteLm, PR_LOG_DEBUG,
	 (MOZILLA_LOCK_PROP
	  " was stolen!  Expected \"%s\", saw \"%s\"!\n",
	  mLockData.get(), data));
    return NS_ERROR_FAILURE;
  }

  if (data)
    XFree(data);
  return NS_OK;
}

nsresult
XRemoteClient::DoSendCommand(Window aWindow, const char *aCommand,
			     PRBool *aDestroyed)
{
  PRBool done = PR_FALSE;
  PRBool accepted = PR_FALSE;
  *aDestroyed = PR_FALSE;

  PR_LOG(sRemoteLm, PR_LOG_DEBUG,
	 ("(writing " MOZILLA_COMMAND_PROP " \"%s\" to 0x%x)\n",
	  aCommand, (unsigned int) aWindow));

  XChangeProperty (mDisplay, aWindow, mMozCommandAtom, XA_STRING, 8,
		   PropModeReplace, (unsigned char *)aCommand,
		   strlen(aCommand));

  while (!done) {
    XEvent event;
    XNextEvent (mDisplay, &event);
    if (event.xany.type == DestroyNotify &&
	event.xdestroywindow.window == aWindow) {
      /* Print to warn user...*/
      PR_LOG(sRemoteLm, PR_LOG_DEBUG,
	     ("window 0x%x was destroyed.\n",
	      (unsigned int) aWindow));
      *aDestroyed = PR_TRUE;
      goto DONE;
    }
    else if (event.xany.type == PropertyNotify &&
	     event.xproperty.state == PropertyNewValue &&
	     event.xproperty.window == aWindow &&
	     event.xproperty.atom == mMozResponseAtom) {
      Atom actual_type;
      int actual_format;
      unsigned long nitems, bytes_after;
      unsigned char *data = 0;
      Bool result;
      result = XGetWindowProperty (mDisplay, aWindow, mMozResponseAtom,
				   0, (65536 / sizeof (long)),
				   True, /* atomic delete after */
				   XA_STRING,
				   &actual_type, &actual_format,
				   &nitems, &bytes_after,
				   &data);
      if (result != Success) {
	PR_LOG(sRemoteLm, PR_LOG_DEBUG,
	       ("failed reading " MOZILLA_RESPONSE_PROP
		" from window 0x%0x.\n",
		(unsigned int) aWindow));
	done = PR_TRUE;
      }
      else if (!data || strlen((char *) data) < 5) {
	PR_LOG(sRemoteLm, PR_LOG_DEBUG,
	       ("invalid data on " MOZILLA_RESPONSE_PROP
		" property of window 0x%0x.\n",
		(unsigned int) aWindow));
	done = PR_TRUE;
      }
      else if (*data == '1') {	/* positive preliminary reply */
	PR_LOG(sRemoteLm, PR_LOG_DEBUG,  ("%s\n", data + 4));
	/* keep going */
	done = PR_FALSE;
      }

      else if (!strncmp ((char *)data, "200", 3)) { /* positive completion */
	accepted = PR_TRUE;
	done = PR_TRUE;
      }

      else if (*data == '2') {	/* positive completion */
	PR_LOG(sRemoteLm, PR_LOG_DEBUG, ("%s\n", data + 4));
	accepted = PR_TRUE;
	done = PR_TRUE;
      }

      else if (*data == '3') {	/* positive intermediate reply */
	PR_LOG(sRemoteLm, PR_LOG_DEBUG,
	       ("internal error: "
		"server wants more information?  (%s)\n",
		data));
	done = PR_TRUE;
      }

      else if (*data == '4' ||	/* transient negative completion */
	       *data == '5') {	/* permanent negative completion */
	PR_LOG(sRemoteLm, PR_LOG_DEBUG, ("%s\n", data + 4));
	done = PR_TRUE;
      }

      else {
	PR_LOG(sRemoteLm, PR_LOG_DEBUG,
	       ("unrecognised " MOZILLA_RESPONSE_PROP
		" from window 0x%x: %s\n",
		(unsigned int) aWindow, data));
	done = PR_TRUE;
      }

      if (data)
	XFree(data);
    }

    else if (event.xany.type == PropertyNotify &&
	     event.xproperty.window == aWindow &&
	       event.xproperty.state == PropertyDelete &&
	     event.xproperty.atom == mMozCommandAtom) {
      PR_LOG(sRemoteLm, PR_LOG_DEBUG,
	     ("(server 0x%x has accepted "
	      MOZILLA_COMMAND_PROP ".)\n",
	      (unsigned int) aWindow));
    }
    
  }

 DONE:

  if (!accepted)
    return NS_ERROR_FAILURE;
  
  return NS_OK;
}

NS_GENERIC_FACTORY_CONSTRUCTOR(XRemoteClient)

static nsModuleComponentInfo components[] =
{
  { "XRemote Client",
    NS_XREMOTECLIENT_CID,
    NS_XREMOTECLIENT_CONTRACTID,
    XRemoteClientConstructor }
};

NS_IMPL_NSGETMODULE(XRemoteClientModule, components);