/*
spacenavd - a free software replacement driver for 6dof space-mice.
Copyright (C) 2007-2019 John Tsiombikas <nuclear@member.fsf.org>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program 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 "config.h"

#ifdef USE_X11
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <setjmp.h>
#ifdef HAVE_ALLOCA_H
#include <alloca.h>
#endif
#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif
#include <unistd.h>
#include <pwd.h>
#include "proto_x11.h"
#include "client.h"
#include "spnavd.h"
#include "dev.h"
#include "xdetect.h"
#include "kbemu.h"

#ifdef HAVE_XINPUT2_H
#include <X11/Xatom.h>
#include <X11/extensions/XInput2.h>
#endif


enum cmd_msg {
	CMD_NONE,
	CMD_APP_WINDOW = 27695,	/* set client window */
	CMD_APP_SENS			/* set app sensitivity */
};


static int xerr(Display *dpy, XErrorEvent *err);
static int xioerr(Display *dpy);

static Display *dpy;
static Window win;
static Atom xa_event_motion, xa_event_bpress, xa_event_brelease;
static Atom xa_event_devdisc, xa_event_cmd;

/* XXX This stands in for the client sensitivity. Due to the
 * bad design of the original magellan protocol, we can't know
 * which client requested the sensitivity change, so we have
 * to keep it global for all X clients.
 */
static float x11_sens = 1.0;

static jmp_buf jbuf;


int init_x11(void)
{
	int i, screen, scr_count;
	Window root;
	XSetWindowAttributes xattr;
	Atom wm_delete, cmd_type;
	XTextProperty tp_wname;
	XClassHint class_hint;
	char *win_title = "Magellan Window";

	if(dpy) return 0;

	/* if the server started from init, it probably won't have a DISPLAY env var
	 * so let's add a default one.
	 */
	if(!getenv("DISPLAY")) {
		putenv("DISPLAY=:0.0");
	}

	/* ... also there won't be an XAUTHORITY env var, so set one up */
	if(!getenv("XAUTHORITY")) {
		struct passwd *p = getpwuid(getuid());
		char *home, *buf;
		if(!p || !p->pw_dir) {
			if(!p) {
				logmsg(LOG_ERR, "getpwuid failed: %s\n", strerror(errno));
			}
			logmsg(LOG_WARNING, "falling back to getting the home directory from the HOME env var...\n");
			if(!(home = getenv("HOME"))) {
				logmsg(LOG_WARNING, "HOME env var not found, using /tmp as a home directory...\n");
				home = "/tmp";
			}
		} else {
			home = p->pw_dir;
		}

		buf = alloca(strlen("XAUTHORITY=") + strlen(home) + strlen("/.Xauthority") + 1);
		sprintf(buf, "XAUTHORITY=%s/.Xauthority", home);
		putenv(buf);
	}

	if(verbose) {
		logmsg(LOG_INFO, "trying to open X11 display \"%s\"\n", getenv("DISPLAY"));
		logmsg(LOG_INFO, "   XAUTHORITY=%s\n", getenv("XAUTHORITY"));
	}

	if(!(dpy = XOpenDisplay(0))) {
		logmsg(LOG_ERR, "failed to open X11 display \"%s\"\n", getenv("DISPLAY"));

		xdet_start();
		return -1;
	}

	XSetErrorHandler(xerr);
	XSetIOErrorHandler(xioerr);

	if(setjmp(jbuf)) {
		return -1;
	}

	scr_count = ScreenCount(dpy);
	screen = DefaultScreen(dpy);
	root = RootWindow(dpy, screen);

	/* intern the various atoms used for communicating with the magellan clients */
	xa_event_motion = XInternAtom(dpy, "MotionEvent", False);
	xa_event_bpress = XInternAtom(dpy, "ButtonPressEvent", False);
	xa_event_brelease = XInternAtom(dpy, "ButtonReleaseEvent", False);
	xa_event_devdisc = XInternAtom(dpy, "DeviceDisconnectEvent", False);
	xa_event_cmd = XInternAtom(dpy, "CommandEvent", False);

	/* Create a dummy window, so that clients are able to send us events
	 * through the magellan API. No need to map the window.
	 */
	xattr.background_pixel = xattr.border_pixel = BlackPixel(dpy, screen);
	xattr.colormap = DefaultColormap(dpy, screen);

	win = XCreateWindow(dpy, root, 0, 0, 10, 10, 0, CopyFromParent, InputOutput,
			DefaultVisual(dpy, screen), CWColormap | CWBackPixel | CWBorderPixel, &xattr);

	wm_delete = XInternAtom(dpy, "WM_DELETE_WINDOW", False);
	XSetWMProtocols(dpy, win, &wm_delete, 1);

	XStringListToTextProperty(&win_title, 1, &tp_wname);
	XSetWMName(dpy, win, &tp_wname);
	XFree(tp_wname.value);

	class_hint.res_name = "magellan";
	class_hint.res_class = "magellan_win";
	XSetClassHint(dpy, win, &class_hint);

	/* I believe this is a bit hackish, but the magellan API expects to find the CommandEvent
	 * property on the root window, containing our window id.
	 * The API doesn't look for a specific property type, so I made one up here (MagellanCmdType).
	 */
	cmd_type = XInternAtom(dpy, "MagellanCmdType", False);
	for(i=0; i<scr_count; i++) {
		Window root = RootWindow(dpy, i);
		XChangeProperty(dpy, root, xa_event_cmd, cmd_type, 32, PropModeReplace, (unsigned char*)&win, 1);
	}
	XFlush(dpy);

	/* pass the display connection to the keyboard emulation module */
	kbemu_set_display(dpy);

	xdet_stop();	/* stop X server detection if it was running */

	drop_xinput();
	return 0;
}

void close_x11(void)
{
	int i, scr_count;
	struct client *cnode;

	if(dpy && setjmp(jbuf) == 0) {
		if(verbose) {
			logmsg(LOG_INFO, "closing X11 connection to display \"%s\"\n", getenv("DISPLAY"));
		}

		/* first delete all the CommandEvent properties from all root windows */
		scr_count = ScreenCount(dpy);
		for(i=0; i<scr_count; i++) {
			Window root = RootWindow(dpy, i);
			XDeleteProperty(dpy, root, xa_event_cmd);
		}

		XDestroyWindow(dpy, win);
		XCloseDisplay(dpy);
		dpy = 0;

		/* stop the kbemu module from using an invalid Display* */
		kbemu_set_display(0);
	}

	/* also remove all x11 clients from the client list */
	cnode = first_client();
	while(cnode) {
		struct client *c = cnode;
		cnode = next_client();

		if(get_client_type(c) == CLIENT_X11) {
			remove_client(c);
		}
	}
}

int get_x11_socket(void)
{
	return dpy ? ConnectionNumber(dpy) : xdet_get_fd();
}

void send_xevent(spnav_event *ev, struct client *c)
{
	int i;
	XEvent xevent;

	if(!dpy) return;

	if(setjmp(jbuf)) {
		return;
	}

	xevent.type = ClientMessage;
	xevent.xclient.send_event = False;
	xevent.xclient.display = dpy;
	xevent.xclient.window = get_client_window(c);

	switch(ev->type) {
	case EVENT_MOTION:
		xevent.xclient.message_type = xa_event_motion;
		xevent.xclient.format = 16;

		for(i=0; i<6; i++) {
			float val = (float)ev->motion.data[i] * x11_sens;
			xevent.xclient.data.s[i + 2] = (short)val;
		}
		xevent.xclient.data.s[0] = xevent.xclient.data.s[1] = 0;
		xevent.xclient.data.s[8] = ev->motion.period;
		break;

	case EVENT_BUTTON:
		xevent.xclient.message_type = ev->button.press ? xa_event_bpress : xa_event_brelease;
		xevent.xclient.format = 16;
		xevent.xclient.data.s[2] = ev->button.bnum;
		break;

	default:
		return;
	}

	XSendEvent(dpy, get_client_window(c), False, 0, &xevent);
	XFlush(dpy);
}

int handle_xevents(fd_set *rset)
{
	if(!dpy) {
		if(xdet_get_fd() != -1) {
			handle_xdet_events(rset);
		}
		return -1;
	}

	/* process any pending X events */
	if(FD_ISSET(ConnectionNumber(dpy), rset)) {
		if(setjmp(jbuf)) {
			return 0;
		}

		while(XPending(dpy)) {
			XEvent xev;
			XNextEvent(dpy, &xev);

			if(xev.type == ClientMessage && xev.xclient.message_type == xa_event_cmd) {
				unsigned int win_id;

				switch(xev.xclient.data.s[2]) {
				case CMD_APP_WINDOW:
					win_id = xev.xclient.data.s[1];
					win_id |= (unsigned int)xev.xclient.data.s[0] << 16;

					set_client_window((Window)win_id);
					break;

				case CMD_APP_SENS:
					x11_sens = *(float*)xev.xclient.data.s;	/* see decl of x11_sens for details */
					break;

				default:
					break;
				}
			}
		}
	}

	return 0;
}

/* adds a new X11 client to the list, IF it does not already exist */
void set_client_window(Window win)
{
	int i, scr_count;
	struct client *cnode;

	/* When a magellan application exits, the SDK sets another window to avoid
	 * crashing the original proprietary daemon.  The new free SDK will set
	 * consistently the root window for that purpose, which we can ignore here
	 * easily.
	 */
	scr_count = ScreenCount(dpy);
	for(i=0; i<scr_count; i++) {
		if(win == RootWindow(dpy, i)) {
			return;
		}
	}

	/* make sure we don't already have that client */
	cnode = first_client();
	while(cnode) {
		if(get_client_window(cnode) == win) {
			return;
		}
		cnode = next_client();
	}

	add_client(CLIENT_X11, &win);
}

void remove_client_window(Window win)
{
	struct client *c, *cnode;

	cnode = first_client();
	while(cnode) {
		c = cnode;
		cnode = next_client();

		if(get_client_window(c) == win) {
			remove_client(c);
			return;
		}
	}
}

void drop_xinput(void)
{
#ifdef HAVE_XINPUT2_H
	XIDeviceInfo *xidevs;
	int i, num_devs;
	static Atom atom_enabled;

	if(!dpy) return;

	if(!atom_enabled) {
		atom_enabled = XInternAtom(dpy, "Device Enabled", False);
	}

	if(!(xidevs = XIQueryDevice(dpy, XIAllDevices, &num_devs))) {
		logmsg(LOG_ERR, "failed to query XInput2 devices\n");
		return;
	}

	for(i=0; i<num_devs; i++) {
		struct device *dev = get_devices();
		while(dev) {
			if(strcmp(dev->name, xidevs[i].name) == 0 && xidevs[i].enabled) {
				unsigned char zero = 0;
				logmsg(LOG_INFO, "Removing device \"%s\" from X server\n", dev->name);

				XIChangeProperty(dpy, xidevs[i].deviceid, atom_enabled, XA_INTEGER, 8, PropModeReplace, &zero, 1);
				break;
			}
			dev = dev->next;
		}
	}
	XIFreeDeviceInfo(xidevs);

#endif	/* HAVE_XINPUT2_H */
}


/* X11 error handler */
static int xerr(Display *dpy, XErrorEvent *err)
{
	char buf[512];

	if(err->error_code == BadWindow) {
		if(verbose) {
			logmsg(LOG_INFO, "Caught BadWindow, dropping client with window: %x\n",
					(unsigned int)err->resourceid);
		}
		/* we may get a BadWindow error when trying to send events to
		 * clients that have disconnected in the meanwhile.
		 */
		remove_client_window((Window)err->resourceid);
	} else {
		XGetErrorText(dpy, err->error_code, buf, sizeof buf);
		logmsg(LOG_ERR, "Caught unexpected X error: %s [op: %d,%d, res: %u]\n", buf,
				(int)err->request_code, (int)err->minor_code, (unsigned int)err->resourceid);
	}
	return 0;
}

/* X11 I/O error handler
 * This function must not return or xlib will abort.
 */
static int xioerr(Display *display)
{
	logmsg(LOG_ERR, "Lost the X server!\n");
	dpy = 0;
	close_x11();
	xdet_start();

	longjmp(jbuf, 1);

	return 0;
}

#else
int spacenavd_proto_x11_shut_up_empty_source_warning;
#endif	/* USE_X11 */