#include <iostream>

#include <X11/Xlib.h>
#include <X11/Xutil.h>

int main (int argc, char *argv[]) {
    Display *display = XOpenDisplay(NULL);
    Window win, root, parent, *children;
    int revert = RevertToParent;
    int screen = DefaultScreen(display);
    unsigned int nchild;
    XGetInputFocus(display, &win, &revert);

    if (win != RootWindow(display, screen)) {
        parent = win;
        do {
            win = parent;
            XQueryTree(display, win, &root, &parent, &children, &nchild);
            XFree(children);
        } while(parent != RootWindow(display, screen));
    }

/*
    Display *display;
    Window win;
    char *name;
    int revert;

    display = XOpenDisplay(NULL);
    XGetInputFocus(display, &win, &revert);
*/

    //char *name;

    Atom nameAtom = XInternAtom(display, "_NET_WM_NAME", true);
    Atom utf8Atom = XInternAtom(display, "UTF8_STRING", true);
    Atom type;
    int format;
    unsigned long nitems, after;
    unsigned char *data = 0;

    int status = XGetWindowProperty(display, win, nameAtom, 0, 65536,
                                    false, /*AnyPropertyType*/ utf8Atom, &type, &format,
                                    &nitems, &after, &data);

    std::cout << "Returned status: " << status << std::endl;
    //std::cout << "Wtf: " << type << " " << nitems << " " << after << std::cout;
    if (data) {
        std::cout << "Active window name: " << data << std::endl;
        XFree(data);
    }

    return 0;
}