/*
 * synergy -- mouse and keyboard sharing utility
 * Copyright (C) 2012 Synergy Si Ltd.
 * Copyright (C) 2002 Chris Schoeneman
 * 
 * This package is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file COPYING that should have accompanied this file.
 * 
 * This package 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "platform/XWindowsScreenSaver.h"

#include "platform/XWindowsUtil.h"
#include "synergy/IPlatformScreen.h"
#include "base/Log.h"
#include "base/Event.h"
#include "base/IEventQueue.h"
#include "base/TMethodEventJob.h"

#include <X11/Xatom.h>
#if HAVE_X11_EXTENSIONS_XTEST_H
#	include <X11/extensions/XTest.h>
#else
#	error The XTest extension is required to build synergy
#endif
#if HAVE_X11_EXTENSIONS_DPMS_H
extern "C" {
#	include <X11/Xmd.h>
#	include <X11/extensions/dpms.h>
#	if !HAVE_DPMS_PROTOTYPES
#		undef DPMSModeOn
#		undef DPMSModeStandby
#		undef DPMSModeSuspend
#		undef DPMSModeOff
#		define DPMSModeOn		0
#		define DPMSModeStandby	1
#		define DPMSModeSuspend	2
#		define DPMSModeOff		3
extern Bool DPMSQueryExtension(Display *, int *, int *);
extern Bool DPMSCapable(Display *);
extern Status DPMSEnable(Display *);
extern Status DPMSDisable(Display *);
extern Status DPMSForceLevel(Display *, CARD16);
extern Status DPMSInfo(Display *, CARD16 *, BOOL *);
#	endif
}
#endif

//
// XWindowsScreenSaver
//

XWindowsScreenSaver::XWindowsScreenSaver(
				Display* display, Window window, void* eventTarget, IEventQueue* events) :
	m_display(display),
	m_xscreensaverSink(window),
	m_eventTarget(eventTarget),
	m_xscreensaver(None),
	m_xscreensaverActive(false),
	m_dpms(false),
	m_disabled(false),
	m_suppressDisable(false),
	m_disableTimer(NULL),
	m_disablePos(0),
	m_events(events)
{
	// get atoms
	m_atomScreenSaver           = XInternAtom(m_display,
										"SCREENSAVER", False);
	m_atomScreenSaverVersion    = XInternAtom(m_display,
										"_SCREENSAVER_VERSION", False);
	m_atomScreenSaverActivate   = XInternAtom(m_display,
										"ACTIVATE", False);
	m_atomScreenSaverDeactivate = XInternAtom(m_display,
										"DEACTIVATE", False);

	// check for DPMS extension.  this is an alternative screen saver
	// that powers down the display.
#if HAVE_X11_EXTENSIONS_DPMS_H
	int eventBase, errorBase;
	if (DPMSQueryExtension(m_display, &eventBase, &errorBase)) {
		if (DPMSCapable(m_display)) {
			// we have DPMS
			m_dpms  = true;
		}
	}
#endif

	// watch top-level windows for changes
	bool error = false;
	{
		XWindowsUtil::ErrorLock lock(m_display, &error);
		Window root = DefaultRootWindow(m_display);
		XWindowAttributes attr;
		XGetWindowAttributes(m_display, root, &attr);
		m_rootEventMask = attr.your_event_mask;
		XSelectInput(m_display, root, m_rootEventMask | SubstructureNotifyMask);
	}
	if (error) {
		LOG((CLOG_DEBUG "didn't set root event mask"));
		m_rootEventMask = 0;
	}

	// get the built-in settings
	XGetScreenSaver(m_display, &m_timeout, &m_interval,
								&m_preferBlanking, &m_allowExposures);

	// get the DPMS settings
	m_dpmsEnabled = isDPMSEnabled();

	// get the xscreensaver window, if any
	if (!findXScreenSaver()) {
		setXScreenSaver(None);
	}

	// install disable timer event handler
	m_events->adoptHandler(Event::kTimer, this,
							new TMethodEventJob<XWindowsScreenSaver>(this,
								&XWindowsScreenSaver::handleDisableTimer));
}

XWindowsScreenSaver::~XWindowsScreenSaver()
{
	// done with disable job
	if (m_disableTimer != NULL) {
		m_events->deleteTimer(m_disableTimer);
	}
	m_events->removeHandler(Event::kTimer, this);

	if (m_display != NULL) {
		enableDPMS(m_dpmsEnabled);
		XSetScreenSaver(m_display, m_timeout, m_interval,
								m_preferBlanking, m_allowExposures);
		clearWatchForXScreenSaver();
		XWindowsUtil::ErrorLock lock(m_display);
		XSelectInput(m_display, DefaultRootWindow(m_display), m_rootEventMask);
	}
}

void
XWindowsScreenSaver::destroy()
{
	m_display = NULL;
	delete this;
}

bool
XWindowsScreenSaver::handleXEvent(const XEvent* xevent)
{
	switch (xevent->type) {
	case CreateNotify:
		if (m_xscreensaver == None) {
			if (isXScreenSaver(xevent->xcreatewindow.window)) {
				// found the xscreensaver
				setXScreenSaver(xevent->xcreatewindow.window);
			}
			else {
				// another window to watch.  to detect the xscreensaver
				// window we look for a property but that property may
				// not yet exist by the time we get this event so we
				// have to watch the window for property changes.
				// this would be so much easier if xscreensaver did the
				// smart thing and stored its window in a property on
				// the root window.
				addWatchXScreenSaver(xevent->xcreatewindow.window);
			}
		}
		break;

	case DestroyNotify:
		if (xevent->xdestroywindow.window == m_xscreensaver) {
			// xscreensaver is gone
			LOG((CLOG_DEBUG "xscreensaver died"));
			setXScreenSaver(None);
			return true;
		}
		break;

	case PropertyNotify:
		if (xevent->xproperty.state == PropertyNewValue) {
			if (isXScreenSaver(xevent->xproperty.window)) {
				// found the xscreensaver
				setXScreenSaver(xevent->xcreatewindow.window);
			}
		}
		break;

	case MapNotify:
		if (xevent->xmap.window == m_xscreensaver) {
			// xscreensaver has activated
			setXScreenSaverActive(true);
			return true;
		}
		break;

	case UnmapNotify:
		if (xevent->xunmap.window == m_xscreensaver) {
			// xscreensaver has deactivated
			setXScreenSaverActive(false);
			return true;
		}
		break;
	}

	return false;
}

void
XWindowsScreenSaver::enable()
{
	// for xscreensaver
	m_disabled = false;
	updateDisableTimer();

	// for built-in X screen saver
	XSetScreenSaver(m_display, m_timeout, m_interval,
								m_preferBlanking, m_allowExposures);

	// for DPMS
	enableDPMS(m_dpmsEnabled);
}

void
XWindowsScreenSaver::disable()
{
	// for xscreensaver
	m_disabled = true;
	updateDisableTimer();

	// use built-in X screen saver
	XGetScreenSaver(m_display, &m_timeout, &m_interval,
								&m_preferBlanking, &m_allowExposures);
	XSetScreenSaver(m_display, 0, m_interval,
								m_preferBlanking, m_allowExposures);

	// for DPMS
	m_dpmsEnabled = isDPMSEnabled();
	enableDPMS(false);

	// FIXME -- now deactivate?
}

void
XWindowsScreenSaver::activate()
{
	// remove disable job timer
	m_suppressDisable = true;
	updateDisableTimer();

	// enable DPMS if it was enabled
	enableDPMS(m_dpmsEnabled);

	// try xscreensaver
	findXScreenSaver();
	if (m_xscreensaver != None) {
		sendXScreenSaverCommand(m_atomScreenSaverActivate);
		return;
	}

	// try built-in X screen saver
	if (m_timeout != 0) {
		XForceScreenSaver(m_display, ScreenSaverActive);
	}

	// try DPMS
	activateDPMS(true);
}

void
XWindowsScreenSaver::deactivate()
{
	// reinstall disable job timer
	m_suppressDisable = false;
	updateDisableTimer();

	// try DPMS
	activateDPMS(false);

	// disable DPMS if screen saver is disabled
	if (m_disabled) {
		enableDPMS(false);
	}

	// try xscreensaver
	findXScreenSaver();
	if (m_xscreensaver != None) {
		sendXScreenSaverCommand(m_atomScreenSaverDeactivate);
		return;
	}

	// use built-in X screen saver
	XForceScreenSaver(m_display, ScreenSaverReset);
}

bool
XWindowsScreenSaver::isActive() const
{
	// check xscreensaver
	if (m_xscreensaver != None) {
		return m_xscreensaverActive;
	}

	// check DPMS
	if (isDPMSActivated()) {
		return true;
	}

	// can't check built-in X screen saver activity
	return false;
}

bool
XWindowsScreenSaver::findXScreenSaver()
{
	// do nothing if we've already got the xscreensaver window
	if (m_xscreensaver == None) {
		// find top-level window xscreensaver window
		Window root = DefaultRootWindow(m_display);
		Window rw, pw, *cw;
		unsigned int nc;
		if (XQueryTree(m_display, root, &rw, &pw, &cw, &nc)) {
			for (unsigned int i = 0; i < nc; ++i) {
				if (isXScreenSaver(cw[i])) {
					setXScreenSaver(cw[i]);
					break;
				}
			}
			XFree(cw);
		}
	}

	return (m_xscreensaver != None);
}

void
XWindowsScreenSaver::setXScreenSaver(Window window)
{
	LOG((CLOG_DEBUG "xscreensaver window: 0x%08x", window));

	// save window
	m_xscreensaver = window;

	if (m_xscreensaver != None) {
		// clear old watch list
		clearWatchForXScreenSaver();

		// see if xscreensaver is active
		bool error = false;
		XWindowAttributes attr;
		{
			XWindowsUtil::ErrorLock lock(m_display, &error);
			XGetWindowAttributes(m_display, m_xscreensaver, &attr);
		}
		setXScreenSaverActive(!error && attr.map_state != IsUnmapped);

		// save current DPMS state;  xscreensaver may have changed it.
		m_dpmsEnabled = isDPMSEnabled();
	}
	else {
		// screen saver can't be active if it doesn't exist
		setXScreenSaverActive(false);

		// start watching for xscreensaver
		watchForXScreenSaver();
	}
}

bool
XWindowsScreenSaver::isXScreenSaver(Window w) const
{
	// check for m_atomScreenSaverVersion string property
	Atom type;
	return (XWindowsUtil::getWindowProperty(m_display, w,
									m_atomScreenSaverVersion,
									NULL, &type, NULL, False) &&
								type == XA_STRING);
}

void
XWindowsScreenSaver::setXScreenSaverActive(bool activated)
{
	if (m_xscreensaverActive != activated) {
		LOG((CLOG_DEBUG "xscreensaver %s on window 0x%08x", activated ? "activated" : "deactivated", m_xscreensaver));
		m_xscreensaverActive = activated;

		// if screen saver was activated forcefully (i.e. against
		// our will) then just accept it.  don't try to keep it
		// from activating since that'll just pop up the password
		// dialog if locking is enabled.
		m_suppressDisable = activated;
		updateDisableTimer();

		if (activated) {
			m_events->addEvent(Event(
							m_events->forIPrimaryScreen().screensaverActivated(),
							m_eventTarget));
		}
		else {
			m_events->addEvent(Event(
							m_events->forIPrimaryScreen().screensaverDeactivated(),
							m_eventTarget));
		}
	}
}

void
XWindowsScreenSaver::sendXScreenSaverCommand(Atom cmd, long arg1, long arg2)
{
	XEvent event;
	event.xclient.type         = ClientMessage;
	event.xclient.display      = m_display;
	event.xclient.window       = m_xscreensaverSink;
	event.xclient.message_type = m_atomScreenSaver;
	event.xclient.format       = 32;
	event.xclient.data.l[0]    = static_cast<long>(cmd);
	event.xclient.data.l[1]    = arg1;
	event.xclient.data.l[2]    = arg2;
	event.xclient.data.l[3]    = 0;
	event.xclient.data.l[4]    = 0;

	LOG((CLOG_DEBUG "send xscreensaver command: %d %d %d", (long)cmd, arg1, arg2));
	bool error = false;
	{
		XWindowsUtil::ErrorLock lock(m_display, &error);
		XSendEvent(m_display, m_xscreensaver, False, 0, &event);
	}
	if (error) {
		findXScreenSaver();
	}
}

void
XWindowsScreenSaver::watchForXScreenSaver()
{
	// clear old watch list
	clearWatchForXScreenSaver();

	// add every child of the root to the list of windows to watch
	Window root = DefaultRootWindow(m_display);
	Window rw, pw, *cw;
	unsigned int nc;
	if (XQueryTree(m_display, root, &rw, &pw, &cw, &nc)) {
		for (unsigned int i = 0; i < nc; ++i) {
			addWatchXScreenSaver(cw[i]);
		}
		XFree(cw);
	}

	// now check for xscreensaver window in case it set the property
	// before we could request property change events.
	if (findXScreenSaver()) {
		// found it so clear out our watch list
		clearWatchForXScreenSaver();
	}
}

void
XWindowsScreenSaver::clearWatchForXScreenSaver()
{
	// stop watching all windows
	XWindowsUtil::ErrorLock lock(m_display);
	for (WatchList::iterator index = m_watchWindows.begin();
								index != m_watchWindows.end(); ++index) {
		XSelectInput(m_display, index->first, index->second);
	}
	m_watchWindows.clear();
}

void
XWindowsScreenSaver::addWatchXScreenSaver(Window window)
{
	// get window attributes
	bool error = false;
	XWindowAttributes attr;
	{
		XWindowsUtil::ErrorLock lock(m_display, &error);
		XGetWindowAttributes(m_display, window, &attr);
	}

	// if successful and window uses override_redirect (like xscreensaver
	// does) then watch it for property changes.  
	if (!error && attr.override_redirect == True) {
		error = false;
		{
			XWindowsUtil::ErrorLock lock(m_display, &error);
			XSelectInput(m_display, window,
								attr.your_event_mask | PropertyChangeMask);
		}
		if (!error) {
			// if successful then add the window to our list
			m_watchWindows.insert(std::make_pair(window, attr.your_event_mask));
		}
	}
}

void
XWindowsScreenSaver::updateDisableTimer()
{
	if (m_disabled && !m_suppressDisable && m_disableTimer == NULL) {
		// 5 seconds should be plenty often to suppress the screen saver
		m_disableTimer = m_events->newTimer(5.0, this);
	}
	else if ((!m_disabled || m_suppressDisable) && m_disableTimer != NULL) {
		m_events->deleteTimer(m_disableTimer);
		m_disableTimer = NULL;
	}
}

void
XWindowsScreenSaver::handleDisableTimer(const Event&, void*)
{
	// send fake mouse motion directly to xscreensaver
	if (m_xscreensaver != None) {
		XEvent event;
		event.xmotion.type         = MotionNotify;
		event.xmotion.display      = m_display;
		event.xmotion.window       = m_xscreensaver;
		event.xmotion.root         = DefaultRootWindow(m_display);
		event.xmotion.subwindow    = None;
		event.xmotion.time         = CurrentTime;
		event.xmotion.x            = m_disablePos;
		event.xmotion.y            = 0;
		event.xmotion.x_root       = m_disablePos;
		event.xmotion.y_root       = 0;
		event.xmotion.state        = 0;
		event.xmotion.is_hint      = NotifyNormal;
		event.xmotion.same_screen  = True;

		XWindowsUtil::ErrorLock lock(m_display);
		XSendEvent(m_display, m_xscreensaver, False, 0, &event);

		m_disablePos = 20 - m_disablePos;
	}
}

void
XWindowsScreenSaver::activateDPMS(bool activate)
{
#if HAVE_X11_EXTENSIONS_DPMS_H
	if (m_dpms) {
		// DPMSForceLevel will generate a BadMatch if DPMS is disabled
		XWindowsUtil::ErrorLock lock(m_display);
		DPMSForceLevel(m_display, activate ? DPMSModeStandby : DPMSModeOn);
	}
#endif
}

void
XWindowsScreenSaver::enableDPMS(bool enable)
{
#if HAVE_X11_EXTENSIONS_DPMS_H
	if (m_dpms) {
		if (enable) {
			DPMSEnable(m_display);
		}
		else {
			DPMSDisable(m_display);
		}
	}
#endif
}

bool
XWindowsScreenSaver::isDPMSEnabled() const
{
#if HAVE_X11_EXTENSIONS_DPMS_H
	if (m_dpms) {
		CARD16 level;
		BOOL state;
		DPMSInfo(m_display, &level, &state);
		return (state != False);
	}
	else {
		return false;
	}
#else
	return false;
#endif
}

bool
XWindowsScreenSaver::isDPMSActivated() const
{
#if HAVE_X11_EXTENSIONS_DPMS_H
	if (m_dpms) {
		CARD16 level;
		BOOL state;
		DPMSInfo(m_display, &level, &state);
		return (level != DPMSModeOn);
	}
	else {
		return false;
	}
#else
	return false;
#endif
}
