#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/Xmu/WinUtil.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

char *get_string_property(Window window, Atom property);

int get_property(
  Window window, Atom property, Atom type, long length,
  unsigned char **value);

Display *display;

int main(int argc, char **argv)
{
  Window root;
  Window parent;
  Window *children;
  unsigned int nchildren;

  if (argc != 1) {
    char *name;
    name = strrchr(argv[0], '/');
    name = name ? name+1 : argv[0];
    fprintf(stderr, "usage: %s\n", name);
    exit(1);
  }

  if ((display = XOpenDisplay(NULL)) == NULL) {
    fprintf(stderr, "cannot open display\n");
    exit(1);
  }

  root = DefaultRootWindow(display);

  XQueryTree(display, root, &root, &parent, &children, &nchildren);

  if (children != NULL) {
    int i;
    for (i=0; i<nchildren; ++i) {
      Window window;
      char *name;
      char *mapped = "";
      Bool free_name = True;
      XWindowAttributes attributes;
      window = XmuClientWindow(display, children[i]);
      if (XGetWindowAttributes(display, window, &attributes)) {
        switch (attributes.map_state) {
          case IsUnmapped: mapped = "U"; break;
          case IsUnviewable: mapped = "!"; break;
          case IsViewable: mapped = "M"; break;
        }
      }
      name = get_string_property(window, XA_WM_NAME);
//      icon = get_string_property(window, XA_WM_ICON_NAME);
      if (name == NULL) {
        name = "";
        free_name = False;
      }
      printf("%ld %s %s\n", window, mapped, name);
      if (free_name)
        XFree(name);
    }
    XFree(children);
  }

  XCloseDisplay(display);
  exit(0);
}

char *get_string_property(Window window, Atom property)
{
  unsigned char *value;
  if (get_property(window, property, XA_STRING, 100L, &value)
    <= 0)
    return NULL;
  return (char *)value;
}

int get_property(
  Window window, Atom property, Atom type, long length,
  unsigned char **value)
{
  Atom real_type;
  int format;
  unsigned long n, extra;

  if (XGetWindowProperty(
        display, window, property, 0L, length, False, type,
        &real_type, &format, &n, &extra, value)
      != Success)
    return -1;
  if (n == 0)
    XFree(*value);
  return n;
}