#include <X11/Xlib.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

Display *display;
Window window;
XEvent event;
int screen;

Atom type;
int format;
unsigned char **clientlist, *titletext;
unsigned long nitems, bytes;
int clientcount, activewin;

void *getproperty (Window win, Atom at, Atom type, int *num_results) {

	Atom type_ret;
	int format = 0;
	unsigned long items = 0;
	unsigned long bytes = 0;
	unsigned char **prop_value;
	int result;

	result = XGetWindowProperty(display, win, at, 0, 0x7fffffff, False, type, &type_ret, &format, &nitems, &bytes, (unsigned char **)&prop_value);

	if (result != 0) {

		printf ("result from XGetWindowProperty not 0, %d instead!\n", result);

	}

	*num_results = nitems;

	return prop_value;

}

char *getwindowname(Window window) {

	char *windowname;
	int items;

	windowname = getproperty(window, XInternAtom(display, "WM_ICON_NAME", True), AnyPropertyType, &items);

	printf("getwindowname(): name for ID %u is ", window); if (windowname) { printf("\"%s\"", windowname); } else { printf("(null)"); } printf("\n");

	return (char *)(windowname ? windowname : "Unnamed Window");

}

int find_active_window() {

	int *activewin;
	int items;

	activewin = getproperty(RootWindow(display, 0), XInternAtom(display, "_NET_ACTIVE_WINDOW", True), AnyPropertyType, &items);

	printf("find_active_window(): active window ID is %d\n", activewin);

	return *activewin;

}

unsigned char **getwindowlist(int *clientcount) {

	int i;

	clientlist = getproperty(RootWindow(display, 0), XInternAtom(display, "_NET_CLIENT_LIST", True), AnyPropertyType, clientcount);

	for (i = 0; i < *clientcount; i++) { printf("getwindowlist(): window %d of %d has ID %d\n", i + 1, *clientcount, clientlist[i]); }

	return clientlist;

}

redraw() {

	int i;

	printf("redraw window\n");

	return;

	for (i = 0; i < clientcount; i++) {

		printf("%s\n", getwindowname((int)clientlist[i]));

	}



}

/*

update on:
- focus
- map/unmap
- title change

focus/map:
- title known

unmap:
- title unknown

*/

int main(void) {

	display = XOpenDisplay(NULL);

	if (display == NULL) {

		fprintf(stderr, "Cannot open display\n");
		exit(1);

	}

	int i, knownwin = 0;

	activewin = find_active_window();

	clientlist = getwindowlist((int *)&clientcount);

	for (i = 0; i < clientcount; i++) {

		XSelectInput (display, (int)clientlist[i], StructureNotifyMask | FocusChangeMask | VisibilityChangeMask);

		printf("%s\n", getwindowname((int)clientlist[i]));

	}

	screen = DefaultScreen(display);

	window = XCreateSimpleWindow(display, RootWindow(display, screen), 10, 10, 100, 100, 1, BlackPixel(display, screen), WhitePixel(display, screen));

	XSelectInput(display, window, ExposureMask | KeyPressMask | ButtonPressMask | StructureNotifyMask);

	Atom wmDeleteMessage = XInternAtom(display, "WM_DELETE_WINDOW", False);
	XSetWMProtocols(display, window, &wmDeleteMessage, 1);

	XMapWindow(display, window);

 	redraw();

	XSelectInput(display, RootWindow(display, screen), PropertyChangeMask | SubstructureNotifyMask);

	while (1) {

		XNextEvent(display, &event);

		//printf("%d\n", event);

		switch (event.type) {

			case ClientMessage:
				if (event.xclient.data.l[0] == wmDeleteMessage) {

					printf("close window\n");

					XCloseDisplay(display);

					exit(0);

				}
				break;

			case ButtonPress:
				printf("buttonpress\n");
				break;

			//case DestroyNotify:
				//printf("destroynotify\n");
				//break;

			//case Expose:
				//printf("expose\n");
				//break;

			case PropertyNotify:

				//printf("propertynotify\n");

				//printf("%s\n", XGetAtomName(display, event.xproperty.atom));

				if (event.xproperty.atom == XInternAtom (display, "_NET_CLIENT_LIST", False)) {

					printf("window created or deleted\n");



				} else if (event.xproperty.atom == XInternAtom (display, "_NET_ACTIVE_WINDOW", False)) {

					printf("active window changed\n");



				}


				break;

			case CreateNotify:

				printf("create window: %d\n", event.xcreatewindow.window);

				break;

			case FocusIn: //skip FocusOut since it'd only generate another event, and thinking about it, it's unneccessary here
				printf("focusin: window %u\n", event.xfocus.window);
				break;

			default:
				break;

		}

	}


}

/*
typedef struct {
		  long flags;

		  int x, y;
		  int width, height;
		  int min_width, min_height;
		  int max_width, max_height;
		  int width_inc, height_inc;
		  struct {
					 int x;
					 int y;
		  } min_aspect, max_aspect;
		  int base_width, base_height;

		  int win_gravity;
} XSizeHints;
*/