/*
gcc -Os -s -oxmodifiers xmodifiers.c -lX11
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>

static void
fatal(const char *str)
{
    fprintf(stderr, "%s\n", str);
    exit(1);
}

static unsigned
ctom(char c)
{
    switch (c)
    {
	case 'S': return ShiftMask;
	case 'L': return LockMask;
	case 'C': return ControlMask;
	case 'a': return Mod1Mask;
	case 'b': return Mod2Mask;
	case 'c': return Mod3Mask;
	case 'd': return Mod4Mask;
	case 'e': return Mod5Mask;
	case '1': return Button1Mask;
	case '2': return Button2Mask;
	case '3': return Button3Mask;
	case '4': return Button4Mask;
	case '5': return Button5Mask;
	default: fatal("invalid qualifier");
    }
    return 0;
}

int
main(int argc, char **argv)
{
    unsigned mask;

    if (argc > 1 && strcmp(argv[1], "-h")==0)
    {
	printf("usage: %s [SLCabcde12345] ...\n", argv[0]);
	printf("checks X11 keyboard qualifiers.  either returns the current set\n");
	printf("or checks if any of the given sets are pressed.\n");
	printf("SLC is Shift/Lock/Control, abcdef = MOD1-5, 12345 = Pointer1-5\n");
	exit(0);
    }

    {
	int i;
	Window w;
	Display *dpy = XOpenDisplay(0);
	if (!dpy)
	    fatal("unable to open display");
	if (!XQueryPointer(dpy, DefaultRootWindow(dpy), &w, &w, &i, &i, &i, &i, &mask))
	    fatal("query pointer failed");
	XCloseDisplay(dpy);
    }

    if (!*++argv)
    {
	char buf[32];
	int i = 0;
	char c, *cs = "SLCabcde12345";
	while (c = *cs++)
	    if (mask & ctom(c))
		buf[i++] = c;
	buf[i] = 0;
	printf("%s\n", buf);
	exit(0);
    }
    else
    {
	char *p;
	while (p = *argv++)
	{
	    unsigned m = 0;
	    while (*p)
		m |= ctom(*p++);
	    if ((mask & m) == m)
		exit(0);
	}
	exit(1);
    }
    return 0;
}