/*
 * Copyright 2010 Johan Veenhuizen
 */

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

#include "wind.h"

#define xatom(name) XInternAtom(dpy, (name), False)

#define NET_WM_STATE_REMOVE 0
#define NET_WM_STATE_ADD 1
#define NET_WM_STATE_TOGGLE 2

static void addclient(Window);
static void delclient(Window);
static unsigned long ewmh_getndesktops(void);
static void setcurrentdesktop(unsigned long);
static void reloadwindowname(struct client *);
static void reloadwindowstate(struct client *);
static void reloadwindowtype(struct client *);
static void reloadwindowdesktop(struct client *);
static Bool hasstate(Window, Atom);
static void removestate(Window, Atom);
static void addstate(Window, Atom);
static void changestate(Window, int, Atom);

/*
 * The list of supported properties. Note that we need to
 * include some properties that we actually never use in
 * the _NET_SUPPORTED list in order to show applications
 * that we do indeed know about them. For example, pagers
 * act strangely if we don't mention _NET_WM_STATE_HIDDEN.
 *
 * NB: Keep this list sorted.
 */
static Atom NET_ACTIVE_WINDOW;
static Atom NET_CLIENT_LIST;
static Atom NET_CLIENT_LIST_STACKING;
static Atom NET_CLOSE_WINDOW;
static Atom NET_CURRENT_DESKTOP;
static Atom NET_DESKTOP_GEOMETRY;
static Atom NET_DESKTOP_VIEWPORT;
static Atom NET_FRAME_EXTENTS;
static Atom NET_NUMBER_OF_DESKTOPS;
static Atom NET_REQUEST_FRAME_EXTENTS;
static Atom NET_SUPPORTED;
static Atom NET_SUPPORTING_WM_CHECK;
static Atom NET_WM_ACTION_CHANGE_DESKTOP;
static Atom NET_WM_ACTION_CLOSE;
static Atom NET_WM_ACTION_FULLSCREEN;
static Atom NET_WM_ACTION_MINIMIZE;
static Atom NET_WM_ALLOWED_ACTIONS;
static Atom NET_WM_DESKTOP;
static Atom NET_WM_ICON_NAME;
static Atom NET_WM_NAME;
static Atom NET_WM_STATE;
static Atom NET_WM_STATE_ABOVE;
static Atom NET_WM_STATE_BELOW;
static Atom NET_WM_STATE_FULLSCREEN;
static Atom NET_WM_STATE_HIDDEN;
static Atom NET_WM_STATE_SKIP_TASKBAR;
static Atom NET_WM_VISIBLE_ICON_NAME;
static Atom NET_WM_VISIBLE_NAME;
static Atom NET_WM_WINDOW_TYPE;
static Atom NET_WM_WINDOW_TYPE_DOCK;
static Atom NET_WORKAREA;

static Atom UTF8_STRING;

static Window wmcheckwin = None;

static struct {
	Window *v;
	size_t n;
	size_t lim;
} clientlist = { NULL, 0, 0 };

void ewmh_notifyclientdesktop(Window w, unsigned long i)
{
	setprop(w, NET_WM_DESKTOP, XA_CARDINAL, 32, &i, 1);
}

void ewmh_notifycurdesk(unsigned long n)
{
	setprop(root, NET_CURRENT_DESKTOP, XA_CARDINAL, 32, &n, 1); 
}

void ewmh_notifyframeextents(Window w, struct extents e)
{
	unsigned long v[4] = { e.left, e.right, e.top, e.bottom };
	setprop(w, NET_FRAME_EXTENTS, XA_CARDINAL, 32, v, NELEM(v));
}

static void addclient(Window w)
{
	if (clientlist.n == clientlist.lim) {
		clientlist.lim += 32;
		clientlist.v = xrealloc(clientlist.v,
			clientlist.lim * sizeof clientlist.v[0]);
	}
	clientlist.v[clientlist.n++] = w;
	setprop(root, NET_CLIENT_LIST, XA_WINDOW, 32,
			clientlist.v, clientlist.n);
}

static void delclient(Window w)
{
	int i;
	for (i = 0; i < clientlist.n && clientlist.v[i] != w; i++)
		;
	if (i < clientlist.n) {
		for (; i < clientlist.n - 1; i++)
			clientlist.v[i] = clientlist.v[i + 1];
		clientlist.n--;
	}
	setprop(root, NET_CLIENT_LIST, XA_WINDOW, 32,
			clientlist.v, clientlist.n);
	if (clientlist.n == 0) {
		free(clientlist.v);
		clientlist.v = NULL;
		clientlist.lim = 0;
	}
}

static unsigned long ewmh_getndesktops(void)
{
	unsigned long ndesk = 1;
	unsigned long n;
	unsigned long *p = getprop(root, NET_NUMBER_OF_DESKTOPS, XA_CARDINAL,
			32, &n);
	if (p != NULL) {
		if (n == 1)
			ndesk = *p & 0xffffffffUL;
		XFree(p);
	}
	return ndesk;
}

void ewmh_notifyndesk(unsigned long n)
{
	long *viewport = xmalloc(n * 2 * sizeof (long));
	long *workarea = xmalloc(n * 4 * sizeof (long));
	for (unsigned long i = 0; i < n; i++) {
		viewport[2 * i + 0] = 0;
		viewport[2 * i + 1] = 0;

		workarea[4 * i + 0] = 0;
		workarea[4 * i + 1] = 0;
		workarea[4 * i + 2] = DisplayWidth(dpy, scr);
		workarea[4 * i + 3] = DisplayHeight(dpy, scr);
	}
	setprop(root, NET_DESKTOP_VIEWPORT, XA_CARDINAL, 32, viewport, n * 2);
	setprop(root, NET_WORKAREA, XA_CARDINAL, 32, workarea, n * 4);
	free(workarea);
	free(viewport);

	setprop(root, NET_NUMBER_OF_DESKTOPS, XA_CARDINAL, 32, &n, 1);
}

static void setcurrentdesktop(unsigned long i)
{
	setprop(root, NET_CURRENT_DESKTOP, XA_CARDINAL, 32, &i, 1);
}

void ewmh_startwm(void)
{
	UTF8_STRING = xatom("UTF8_STRING");

	Atom v[] = {
		// Keep sorted
		NET_ACTIVE_WINDOW = xatom("_NET_ACTIVE_WINDOW"),
		NET_CLIENT_LIST = xatom("_NET_CLIENT_LIST"),
		NET_CLIENT_LIST_STACKING = xatom("_NET_CLIENT_LIST_STACKING"),
		NET_CLOSE_WINDOW = xatom("_NET_CLOSE_WINDOW"),
		NET_CURRENT_DESKTOP = xatom("_NET_CURRENT_DESKTOP"),
		NET_DESKTOP_GEOMETRY = xatom("_NET_DESKTOP_GEOMETRY"),
		NET_DESKTOP_VIEWPORT = xatom("_NET_DESKTOP_VIEWPORT"),
		NET_FRAME_EXTENTS = xatom("_NET_FRAME_EXTENTS"),
		NET_NUMBER_OF_DESKTOPS = xatom("_NET_NUMBER_OF_DESKTOPS"),
		NET_REQUEST_FRAME_EXTENTS =
			xatom("_NET_REQUEST_FRAME_EXTENTS"),
		NET_SUPPORTED = xatom("_NET_SUPPORTED"),
		NET_SUPPORTING_WM_CHECK = xatom("_NET_SUPPORTING_WM_CHECK"),
		NET_WM_ACTION_CHANGE_DESKTOP =
			xatom("_NET_WM_ACTION_CHANGE_DESKTOP"),
		NET_WM_ACTION_CLOSE = xatom("_NET_WM_ACTION_CLOSE"),
		NET_WM_ACTION_FULLSCREEN = xatom("_NET_WM_ACTION_FULLSCREEN"),
		NET_WM_ACTION_MINIMIZE = xatom("_NET_WM_ACTION_MINIMIZE"),
		NET_WM_ALLOWED_ACTIONS = xatom("_NET_WM_ALLOWED_ACTIONS"),
		NET_WM_DESKTOP = xatom("_NET_WM_DESKTOP"),
		NET_WM_ICON_NAME = xatom("_NET_WM_ICON_NAME"),
		NET_WM_NAME = xatom("_NET_WM_NAME"),
		NET_WM_STATE = xatom("_NET_WM_STATE"),
		NET_WM_STATE_ABOVE = xatom("_NET_WM_STATE_ABOVE"),
		NET_WM_STATE_BELOW = xatom("_NET_WM_STATE_BELOW"),
		NET_WM_STATE_FULLSCREEN = xatom("_NET_WM_STATE_FULLSCREEN"),
		NET_WM_STATE_HIDDEN = xatom("_NET_WM_STATE_HIDDEN"),
		NET_WM_STATE_SKIP_TASKBAR =
			xatom("_NET_WM_STATE_SKIP_TASKBAR"),
		NET_WM_VISIBLE_ICON_NAME = xatom("_NET_WM_VISIBLE_ICON_NAME"),
		NET_WM_VISIBLE_NAME = xatom("_NET_WM_VISIBLE_NAME"),
		NET_WM_WINDOW_TYPE = xatom("_NET_WM_WINDOW_TYPE"),
		NET_WM_WINDOW_TYPE_DOCK = xatom("_NET_WM_WINDOW_TYPE_DOCK"),
		NET_WORKAREA = xatom("_NET_WORKAREA"),
	};
	setprop(root, NET_SUPPORTED, XA_ATOM, 32, v, NELEM(v));

	long geometry[2] = { DisplayWidth(dpy, scr), DisplayHeight(dpy, scr) };
	setprop(root, NET_DESKTOP_GEOMETRY, XA_CARDINAL, 32, geometry, 2);

	setndesk(ewmh_getndesktops());

	unsigned long n = 0;
	unsigned long *deskp = getprop(root, NET_CURRENT_DESKTOP,
			XA_CARDINAL, 32, &n);
	setcurrentdesktop(0);
	if (deskp != NULL) {
		if (n == 1) {
			gotodesk(*deskp & 0xffffffffUL);
			refocus(CurrentTime);
		}
		XFree(deskp);
	}

	Window none = None;
	setprop(root, NET_ACTIVE_WINDOW, XA_WINDOW, 32, &none, 1);

	// Finally create the WM_CHECK window to announce our EWMH support.
	wmcheckwin = XCreateWindow(dpy, root, 0, 0, 1, 1, 0, CopyFromParent,
			InputOnly, CopyFromParent, CWOverrideRedirect,
			&(XSetWindowAttributes){ .override_redirect = True });
	setprop(wmcheckwin, NET_SUPPORTING_WM_CHECK, XA_WINDOW, 32,
			&wmcheckwin, 1);
	setprop(wmcheckwin, NET_WM_NAME, UTF8_STRING, 8,
			WM_OFFICIAL_NAME, strlen(WM_OFFICIAL_NAME));
	setprop(root, NET_SUPPORTING_WM_CHECK, XA_WINDOW, 32,
			&wmcheckwin, 1);
}

void ewmh_stopwm(void)
{
	XDestroyWindow(dpy, wmcheckwin);
}

static void reloadwindowname(struct client *c)
{
	unsigned long n = 0;
	char *name = getprop(cgetwin(c), NET_WM_NAME, UTF8_STRING, 8, &n);
	csetnetwmname(c, name);
	if (name != NULL)
		XFree(name);
}

static void reloadwindowstate(struct client *c)
{
	Window w = cgetwin(c);
	Bool skiptaskbar = False;
	Bool isfullscreen = False;

	unsigned long n = 0;
	Atom *states = getprop(w, NET_WM_STATE, XA_ATOM, 32, &n);
	for (int i = 0; i < n; i++)
		if (states[i] == NET_WM_STATE_SKIP_TASKBAR)
			skiptaskbar = True;
		else if (states[i] == NET_WM_STATE_FULLSCREEN)
			isfullscreen = True;
		else
			removestate(w, states[i]);
	if (states != NULL)
		XFree(states);

	csetskiptaskbar(c, skiptaskbar);
	csetfull(c, isfullscreen);
}

static void reloadwindowtype(struct client *c)
{
	Bool isdock = False;

	unsigned long n = 0;
	Atom *types = getprop(cgetwin(c), NET_WM_WINDOW_TYPE, XA_ATOM, 32, &n);
	if (types != NULL) {
		for (unsigned long i = 0; i < n; i++)
			if (types[i] == NET_WM_WINDOW_TYPE_DOCK)
				isdock = True;
		XFree(types);
	}

	csetdock(c, isdock);
}

static void reloadwindowdesktop(struct client *c)
{
	Window w = cgetwin(c);
	unsigned long n = 0;
	long *deskp = getprop(w, NET_WM_DESKTOP, XA_CARDINAL, 32, &n);
	if (deskp != NULL) {
		if (n == 1)
			csetdesk(c, *deskp & 0xffffffffUL);
		XFree(deskp);
	} else
		ewmh_notifyclientdesktop(w, cgetdesk(c));
}

void ewmh_maprequest(struct client *c)
{
	/*
	 * The order of the following calls is optimized
	 * for visual appearance.
	 */
	reloadwindowdesktop(c);
	reloadwindowstate(c);
	reloadwindowtype(c);
}

void ewmh_manage(struct client *c)
{
	Window w = cgetwin(c);

	addclient(w);

	// Remove properties that other window managers may have set.
	XDeleteProperty(dpy, w, NET_WM_VISIBLE_NAME);
	XDeleteProperty(dpy, w, NET_WM_VISIBLE_ICON_NAME);

	Atom v[] = {
		NET_WM_ACTION_CHANGE_DESKTOP,
		NET_WM_ACTION_CLOSE,
		NET_WM_ACTION_FULLSCREEN,
	};
	setprop(w, NET_WM_ALLOWED_ACTIONS, XA_ATOM, 32, v, NELEM(v));

	/*
	 * The order of the following calls is optimized
	 * for visual appearance.
	 */
	reloadwindowdesktop(c);
	reloadwindowstate(c);
	reloadwindowname(c);
	reloadwindowtype(c);
}

void ewmh_unmanage(struct client *c)
{
	Window w = cgetwin(c);
	ewmh_notifyfocus(w, None);
	delclient(w);
	XDeleteProperty(dpy, w, NET_WM_ALLOWED_ACTIONS);
}

void ewmh_withdraw(struct client *c)
{
	Window w = cgetwin(c);
	ewmh_notifyfocus(w, None);
	delclient(w);

	/*
	 * EWMH says we should remove _NET_WM_STATE when a window is
	 * withdrawn, but not when we're shutting down (unmanage).
	 */
	XDeleteProperty(dpy, w, NET_WM_STATE);
}

/*
 * Notify change in focus. The focus change is only
 * accepted if 'old' matches the last recorded focus
 * window, or if it is None.
 *
 * The reason this function takes two arguments is to
 * avoid race conditions between FocusIn and FocusOut
 * events.
 *
 * A FocusIn handler should use None as 'old' and the
 * event window as 'new', while a FocusOut handler
 * should use the event window as 'old' and None as
 * 'new'. This way, it doesn't matter in which order
 * the events are reported.
 */
void ewmh_notifyfocus(Window old, Window new)
{
	// The last recorded focus window
	static Window current = None;

	if (old == None || old == current) {
		setprop(root, NET_ACTIVE_WINDOW, XA_WINDOW, 32, &new, 1);
		current = new;
	}
}

void ewmh_notifyrestack(void)
{
	Window *v;
	size_t n;
	getwindowstack(&v, &n);
	setprop(root, NET_CLIENT_LIST_STACKING, XA_WINDOW, 32, v, n);
	free(v);
}

void ewmh_propertynotify(struct client *c, XPropertyEvent *e)
{
	if (e->atom == NET_WM_NAME)
		reloadwindowname(c);
}

static Bool hasstate(Window w, Atom state)
{
	unsigned long n = 0;
	Atom *v = getprop(w, NET_WM_STATE, XA_ATOM, 32, &n);
	Bool rval = False;
	for (unsigned long i = 0; i < n; i++)
		if (v[i] == state)
			rval = True;
	if (v != NULL)
		XFree(v);
	return rval;
}

static void removestate(Window w, Atom state)
{
	unsigned long n = 0;
	Atom *v = getprop(w, NET_WM_STATE, XA_ATOM, 32, &n);
	for (unsigned long i = 0; i < n; i++)
		if (v[i] == state)
			v[i] = v[--n];
	setprop(w, NET_WM_STATE, XA_ATOM, 32, v, n);
	if (v != NULL)
		XFree(v);
}

static void addstate(Window w, Atom state)
{
	unsigned long n = 0;
	Atom *old = getprop(w, NET_WM_STATE, XA_ATOM, 32, &n);
	Atom *new = xmalloc((n + 1) * sizeof (Atom));
	for (unsigned long i = 0; i < n; i++)
		new[i] = old[i];
	new[n] = state;
	setprop(w, NET_WM_STATE, XA_ATOM, 32, new, n + 1);
	free(new);
	if (old != NULL)
		XFree(old);
}

static void changestate(Window w, int how, Atom state)
{
	switch (how) {
	case NET_WM_STATE_REMOVE:
		removestate(w, state);
		break;
	case NET_WM_STATE_ADD:
		addstate(w, state);
		break;
	case NET_WM_STATE_TOGGLE:
		if (hasstate(w, state))
			removestate(w, state);
		else
			addstate(w, state);
		break;
	}
}

void ewmh_notifyfull(Window w, Bool full)
{
	if (full) {
		if (!hasstate(w, NET_WM_STATE_FULLSCREEN))
			addstate(w, NET_WM_STATE_FULLSCREEN);
	} else
		removestate(w, NET_WM_STATE_FULLSCREEN);
}

void ewmh_clientmessage(struct client *c, XClientMessageEvent *e)
{
	if (e->message_type == NET_ACTIVE_WINDOW && e->format == 32) {
		cpopgrp(c);
		gotodesk(cgetdesk(c));
		cfocus(c, (Time)e->data.l[1]);
	} else if (e->message_type == NET_CLOSE_WINDOW && e->format == 32) {
		cdelete(c, (Time)e->data.l[0]);
	} else if (e->message_type == NET_WM_DESKTOP && e->format == 32) {
		csetdesk(c, e->data.l[0] & 0xffffffff);
	} else if (e->message_type == NET_WM_STATE && e->format == 32) {
		int how = e->data.l[0];
		for (int i = 1; i <= 2; i++)
			if (e->data.l[i] != 0)
				changestate(cgetwin(c), how, e->data.l[i]);
		reloadwindowstate(c);
	}
}

void ewmh_rootclientmessage(XClientMessageEvent *e)
{
	if (e->message_type == NET_CURRENT_DESKTOP && e->format == 32) {
		gotodesk(e->data.l[0]);
		refocus(e->data.l[1]);
	} else if (e->message_type == NET_REQUEST_FRAME_EXTENTS) {
		struct extents ext = estimateframeextents(e->window);
		ewmh_notifyframeextents(e->window, ext);
	} else if (e->message_type == NET_NUMBER_OF_DESKTOPS &&
			e->format == 32) {
		setndesk(e->data.l[0]);
	}
}