/*	$OpenBSD: emumb.c,v 1.14 2015/12/25 15:08:28 matthieu Exp $ */
/*
 * Copyright 1990,91 by Thomas Roell, Dinkelscherben, Germany.
 * Copyright 1993 by David Dawes <dawes@xfree86.org>
 * Copyright 2002 by SuSE Linux AG, Author: Egbert Eich
 * Copyright 1994-2002 by The XFree86 Project, Inc.
 * Copyright 2002 by Paul Elliott
 * (Ported from xf86-input-mouse, above copyrights taken from there)
 * Copyright © 2008 University of South Australia
 * Copyright © 2009 Matthieu Herrb <matthieu@herrb.eu>
 *
 * 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, and that the name of the authors
 * not be used in advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.  The authors make no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied
 * warranty.
 *
 * THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
 * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

/* Middle mouse button emulation code. */

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

#include <sys/time.h>

#include <xorg-server.h>
#include <X11/Xatom.h>
#include <xf86.h>
#include <xf86_OSproc.h>
#include <X11/extensions/XI.h>
#include <X11/extensions/XIproto.h>
#include <xf86Xinput.h>
#include <exevents.h>

#include <ws-properties.h>
#include "ws.h"

enum {
	MBEMU_DISABLED = 0,
	MBEMU_ENABLED,
	MBEMU_AUTO
};

static Atom prop_mbemu;		/* Middle button emulation on/off property */
static Atom prop_mbtimeout;	/* Middle button timeout property */

/*
 * Lets create a simple finite-state machine for 3 button emulation:
 *
 * We track buttons 1 and 3 (left and right).  There are 11 states:
 *   0 ground           - initial state
 *   1 delayed left     - left pressed, waiting for right
 *   2 delayed right    - right pressed, waiting for left
 *   3 pressed middle   - right and left pressed, emulated middle sent
 *   4 pressed left     - left pressed and sent
 *   5 pressed right    - right pressed and sent
 *   6 released left    - left released after emulated middle
 *   7 released right   - right released after emulated middle
 *   8 repressed left   - left pressed after released left
 *   9 repressed right  - right pressed after released right
 *  10 pressed both     - both pressed, not emulating middle
 *
 * At each state, we need handlers for the following events
 *   0: no buttons down
 *   1: left button down
 *   2: right button down
 *   3: both buttons down
 *   4: emulate3Timeout passed without a button change
 * Note that button events are not deltas, they are the set of buttons being
 * pressed now.  It's possible (ie, mouse hardware does it) to go from (eg)
 * left down to right down without anything in between, so all cases must be
 * handled.
 *
 * a handler consists of three values:
 *   0: action1
 *   1: action2
 *   2: new emulation state
 *
 * action > 0: ButtonPress
 * action = 0: nothing
 * action < 0: ButtonRelease
 *
 * The comment preceeding each section is the current emulation state.
 * The comments to the right are of the form
 *      <button state> (<events>) -> <new emulation state>
 * which should be read as
 *      If the buttons are in <button state>, generate <events> then go to
 *      <new emulation state>.
 */
static signed char stateTab[11][5][3] = {
/* 0 ground */
  {
    {  0,  0,  0 },   /* nothing -> ground (no change) */
    {  0,  0,  1 },   /* left -> delayed left */
    {  0,  0,  2 },   /* right -> delayed right */
    {  2,  0,  3 },   /* left & right (middle press) -> pressed middle */
    {  0,  0, -1 }    /* timeout N/A */
  },
/* 1 delayed left */
  {
    {  1, -1,  0 },   /* nothing (left event) -> ground */
    {  0,  0,  1 },   /* left -> delayed left (no change) */
    {  1, -1,  2 },   /* right (left event) -> delayed right */
    {  2,  0,  3 },   /* left & right (middle press) -> pressed middle */
    {  1,  0,  4 },   /* timeout (left press) -> pressed left */
  },
/* 2 delayed right */
  {
    {  3, -3,  0 },   /* nothing (right event) -> ground */
    {  3, -3,  1 },   /* left (right event) -> delayed left (no change) */
    {  0,  0,  2 },   /* right -> delayed right (no change) */
    {  2,  0,  3 },   /* left & right (middle press) -> pressed middle */
    {  3,  0,  5 },   /* timeout (right press) -> pressed right */
  },
/* 3 pressed middle */
  {
    { -2,  0,  0 },   /* nothing (middle release) -> ground */
    {  0,  0,  7 },   /* left -> released right */
    {  0,  0,  6 },   /* right -> released left */
    {  0,  0,  3 },   /* left & right -> pressed middle (no change) */
    {  0,  0, -1 },   /* timeout N/A */
  },
/* 4 pressed left */
  {
    { -1,  0,  0 },   /* nothing (left release) -> ground */
    {  0,  0,  4 },   /* left -> pressed left (no change) */
    { -1,  0,  2 },   /* right (left release) -> delayed right */
    {  3,  0, 10 },   /* left & right (right press) -> pressed both */
    {  0,  0, -1 },   /* timeout N/A */
  },
/* 5 pressed right */
  {
    { -3,  0,  0 },   /* nothing (right release) -> ground */
    { -3,  0,  1 },   /* left (right release) -> delayed left */
    {  0,  0,  5 },   /* right -> pressed right (no change) */
    {  1,  0, 10 },   /* left & right (left press) -> pressed both */
    {  0,  0, -1 },   /* timeout N/A */
  },
/* 6 released left */
  {
    { -2,  0,  0 },   /* nothing (middle release) -> ground */
    { -2,  0,  1 },   /* left (middle release) -> delayed left */
    {  0,  0,  6 },   /* right -> released left (no change) */
    {  1,  0,  8 },   /* left & right (left press) -> repressed left */
    {  0,  0, -1 },   /* timeout N/A */
  },
/* 7 released right */
  {
    { -2,  0,  0 },   /* nothing (middle release) -> ground */
    {  0,  0,  7 },   /* left -> released right (no change) */
    { -2,  0,  2 },   /* right (middle release) -> delayed right */
    {  3,  0,  9 },   /* left & right (right press) -> repressed right */
    {  0,  0, -1 },   /* timeout N/A */
  },
/* 8 repressed left */
  {
    { -2, -1,  0 },   /* nothing (middle release, left release) -> ground */
    { -2,  0,  4 },   /* left (middle release) -> pressed left */
    { -1,  0,  6 },   /* right (left release) -> released left */
    {  0,  0,  8 },   /* left & right -> repressed left (no change) */
    {  0,  0, -1 },   /* timeout N/A */
  },
/* 9 repressed right */
  {
    { -2, -3,  0 },   /* nothing (middle release, right release) -> ground */
    { -3,  0,  7 },   /* left (right release) -> released right */
    { -2,  0,  5 },   /* right (middle release) -> pressed right */
    {  0,  0,  9 },   /* left & right -> repressed right (no change) */
    {  0,  0, -1 },   /* timeout N/A */
  },
/* 10 pressed both */
  {
    { -1, -3,  0 },   /* nothing (left release, right release) -> ground */
    { -3,  0,  4 },   /* left (right release) -> pressed left */
    { -1,  0,  5 },   /* right (left release) -> pressed right */
    {  0,  0, 10 },   /* left & right -> pressed both (no change) */
    {  0,  0, -1 },   /* timeout N/A */
  },
};

int
wsmbEmuTimer(InputInfoPtr pInfo)
{
	WSDevicePtr priv = (WSDevicePtr)pInfo->private;
	int sigstate;
	int id;

	sigstate = xf86BlockSIGIO();

	priv->emulateMB.pending = FALSE;
	if ((id = stateTab[priv->emulateMB.state][4][0]) != 0) {
		xf86PostButtonEvent(pInfo->dev, 0, abs(id), (id >= 0), 0, 0);
		priv->emulateMB.state = stateTab[priv->emulateMB.state][4][2];
	} else {
		xf86IDrvMsg(pInfo, X_ERROR,
		    "Got unexpected buttonTimer in state %d\n",
		    priv->emulateMB.state);
	}

	xf86UnblockSIGIO(sigstate);
	return 0;
}

/**
 * Emulate a middle button on button press.
 *
 * @param code button number (1 for left, 3 for right)
 * @param press TRUE if press, FALSE if release.
 *
 * @return TRUE if event was swallowed by middle mouse button emulation, FALSE
 * otherwise.
 */
BOOL
wsmbEmuFilterEvent(InputInfoPtr pInfo, int button, BOOL press)
{
	WSDevicePtr priv = (WSDevicePtr)pInfo->private;
	int id;
	int *btstate;
	int ret = FALSE;

	if (!priv->emulateMB.enabled)
		return ret;

	/* Disable emulation when middle button event is detected */
	if (button == 2 && priv->emulateMB.enabled == MBEMU_AUTO) {
		priv->emulateMB.enabled = FALSE;
		return ret;
	}

	/* don't care about other buttons */
	if (button != 1 && button != 3)
		return ret;

	btstate = &priv->emulateMB.buttonstate;
	if (press)
		*btstate |= (button == 1) ? 0x1 : 0x2;
	else
		*btstate &= (button == 1) ? ~0x1 : ~0x2;

	if ((id = stateTab[priv->emulateMB.state][*btstate][0]) != 0) {
		xf86PostButtonEvent(pInfo->dev, 0, abs(id), (id >= 0), 0, 0);
		ret = TRUE;
	}
	if ((id = stateTab[priv->emulateMB.state][*btstate][1]) != 0) {
		xf86PostButtonEvent(pInfo->dev, 0, abs(id), (id >= 0), 0, 0);
		ret = TRUE;
	}

	priv->emulateMB.state = stateTab[priv->emulateMB.state][*btstate][2];

	if (stateTab[priv->emulateMB.state][4][0] != 0) {
		priv->emulateMB.expires = GetTimeInMillis()
		    + priv->emulateMB.timeout;
		priv->emulateMB.pending = TRUE;
		ret = TRUE;
	} else {
		priv->emulateMB.pending = FALSE;
	}
	return ret;
}

void
wsmbEmuWakeupHandler(pointer data, int i, pointer LastSelectMask)
{
	InputInfoPtr pInfo = (InputInfoPtr)data;
	WSDevicePtr priv = (WSDevicePtr)pInfo->private;
	int ms;

	if (priv->emulateMB.pending) {
		ms = priv->emulateMB.expires - GetTimeInMillis();
		if (ms <= 0)
			wsmbEmuTimer(pInfo);
	}
}

void
wsmbEmuBlockHandler(pointer data, struct timeval **waitTime,
    pointer LastSelectMask)
{
	InputInfoPtr pInfo = (InputInfoPtr)data;
	WSDevicePtr priv = (WSDevicePtr)pInfo->private;
	int ms;

	if (priv->emulateMB.pending) {
		ms = priv->emulateMB.expires - GetTimeInMillis();
		if (ms <= 0)
			ms = 0;
		AdjustWaitForDelay(waitTime, ms);
	}
}

void
wsmbEmuPreInit(InputInfoPtr pInfo)
{
	WSDevicePtr priv = (WSDevicePtr)pInfo->private;
	int timeout;

	DBG(1, ErrorF("wsmbEmuPreInit\n"));

	priv->emulateMB.enabled = MBEMU_AUTO;
	if (xf86FindOption(pInfo->options, "Emulate3Buttons")) {
		priv->emulateMB.enabled = xf86SetBoolOption(pInfo->options,
		    "Emulate3Buttons",
		    MBEMU_ENABLED);
		xf86IDrvMsg(pInfo, X_INFO, "Forcing middle mouse button "
		    "emulation %s.\n",
		    (priv->emulateMB.enabled) ? "on" : "off");
	}

	timeout = xf86SetIntOption(pInfo->options, "Emulate3Timeout", 50);
	if (timeout < 0) {
		xf86IDrvMsg(pInfo, X_WARNING,
		    "Invalid Emulate3Timeout value: %d\n", timeout);
		xf86IDrvMsg(pInfo, X_WARNING, "Using built-in timeout value\n");
		timeout = 50;
	}
	priv->emulateMB.timeout = timeout;
}

void
wsmbEmuOn(InputInfoPtr pInfo)
{
	RegisterBlockAndWakeupHandlers(wsmbEmuBlockHandler,
	    wsmbEmuWakeupHandler, (pointer)pInfo);
}

void
wsmbEmuFinalize(InputInfoPtr pInfo)
{
	RemoveBlockAndWakeupHandlers(wsmbEmuBlockHandler,
	    wsmbEmuWakeupHandler, (pointer)pInfo);
}

static int
wsmbEmuSetProperty(DeviceIntPtr dev, Atom atom, XIPropertyValuePtr val,
    BOOL checkonly)
{
	InputInfoPtr pInfo = (InputInfoPtr)dev->public.devicePrivate;
	WSDevicePtr priv = (WSDevicePtr)pInfo->private;

	DBG(1, ErrorF("wsmbEmuSetProperty %s\n", NameForAtom(atom)));

	if (atom == prop_mbemu) {
		if (val->format != 8 || val->size != 1 ||
		    val->type != XA_INTEGER)
			return BadMatch;

		if (!checkonly)
			priv->emulateMB.enabled = *((BOOL*)val->data);
	} else if (atom == prop_mbtimeout) {
		int timeout;

		if (val->format != 32 || val->size != 1 ||
		    val->type != XA_INTEGER)
			return BadMatch;

		timeout = *((CARD32*)val->data);

		if (timeout < 0)
			return BadValue;

		if (!checkonly)
			priv->emulateMB.timeout = timeout;
	}

	return Success;
}

/**
 * Initialise property for MB emulation on/off.
 */
void
wsmbEmuInitProperty(DeviceIntPtr dev)
{
	InputInfoPtr pInfo = (InputInfoPtr)dev->public.devicePrivate;
	WSDevicePtr priv = (WSDevicePtr)pInfo->private;
	int rc;

	DBG(1, ErrorF("wsmbEmuInitProperty\n"));

	prop_mbemu = MakeAtom(WS_PROP_MIDBUTTON,
	    strlen(WS_PROP_MIDBUTTON), TRUE);
	rc = XIChangeDeviceProperty(dev, prop_mbemu, XA_INTEGER, 8,
	    PropModeReplace, 1, &priv->emulateMB.enabled, FALSE);
	if (rc != Success) {
		xf86IDrvMsg(pInfo, X_ERROR,
		    "cannot create device property %s: %d\n",
		    WS_PROP_MIDBUTTON, rc);
		return;
	}
	XISetDevicePropertyDeletable(dev, prop_mbemu, FALSE);

	prop_mbtimeout = MakeAtom(WS_PROP_MIDBUTTON_TIMEOUT,
	    strlen(WS_PROP_MIDBUTTON_TIMEOUT), TRUE);
	rc = XIChangeDeviceProperty(dev, prop_mbtimeout, XA_INTEGER, 32,
	    PropModeReplace, 1, &priv->emulateMB.timeout, FALSE);
	if (rc != Success) {
		xf86IDrvMsg(pInfo, X_ERROR,
		    "cannot create device property %s: %d\n",
		    WS_PROP_MIDBUTTON_TIMEOUT, rc);
		return;
	}
	XISetDevicePropertyDeletable(dev, prop_mbtimeout, FALSE);

	XIRegisterPropertyHandler(dev, wsmbEmuSetProperty, NULL, NULL);
}