/* See LICENSE file for copyright and license details.

 *

 * dynamic window manager is designed like any other X client as well. It is

 * driven through handling X events. In contrast to other X clients, a window

 * manager selects for SubstructureRedirectMask on the root window, to receive

 * events about window (dis-)appearance.  Only one X connection at a time is

 * allowed to select for this event mask.

 *

 * Calls to fetch an X event from the event queue are blocking.  Due reading

 * status text from standard input, a select()-driven main loop has been

 * implemented which selects for reads on the X connection and STDIN_FILENO to

 * handle all data smoothly. The event handlers of dwm are organized in an

 * array which is accessed whenever a new event has been fetched. This allows

 * event dispatching in O(1) time.

 *

 * Each child of the root window is called a client, except windows which have

 * set the override_redirect flag.  Clients are organized in a global

 * doubly-linked client list, the focus history is remembered through a global

 * stack list. Each client contains an array of Bools of the same size as the

 * global tags array to indicate the tags of a client.  For each client dwm

 * creates a small title window, which is resized whenever the (_NET_)WM_NAME

 * properties are updated or the client is moved/resized.

 *

 * Keys and tagging rules are organized as arrays and defined in the config.h

 * file. These arrays are kept static in event.o and tag.o respectively,

 * because no other part of dwm needs access to them.  The current layout is

 * represented by the lt pointer.

 *

 * To understand everything else, start reading main().

 */

#include <errno.h>

#include <locale.h>

#include <regex.h>

#include <stdarg.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/select.h>

#include <sys/wait.h>

#include <X11/cursorfont.h>

#include <X11/keysym.h>

#include <X11/Xatom.h>

#include <X11/Xproto.h>

#include <X11/Xutil.h>

/* macros */

#define BUTTONMASK		(ButtonPressMask | ButtonReleaseMask)

#define CLEANMASK(mask)		(mask & ~(numlockmask | LockMask))

#define MOUSEMASK		(BUTTONMASK | PointerMotionMask)

/* enums */

enum { BarTop, BarBot, BarOff };			/* bar position */

enum { CurNormal, CurResize, CurMove, CurLast };	/* cursor */

enum { ColBorder, ColFG, ColBG, ColLast };		/* color */

enum { NetSupported, NetWMName, NetLast };		/* EWMH atoms */

enum { WMProtocols, WMDelete, WMName, WMState, WMLast };/* default atoms */

/* typedefs */

typedef struct Client Client;

struct Client {

	char name[256];

	int x, y, w, h;

	int rx, ry, rw, rh; /* revert geometry */

	int basew, baseh, incw, inch, maxw, maxh, minw, minh;

	int minax, maxax, minay, maxay;

	long flags; 

	unsigned int border, oldborder;

	Bool isbanned, isfixed, ismax, isfloating;

	Bool *tags;

	Client *next;

	Client *prev;

	Client *snext;

	Window win;

};

typedef struct {

	int x, y, w, h;

	unsigned long norm[ColLast];

	unsigned long sel[ColLast];

	Drawable drawable;

	GC gc;

	struct {

		int ascent;

		int descent;

		int height;

		XFontSet set;

		XFontStruct *xfont;

	} font;

} DC; /* draw context */

typedef struct {

	unsigned long mod;

	KeySym keysym;

	void (*func)(const char *arg);

	const char *arg;

} Key;

typedef struct {

	const char *symbol;

	void (*arrange)(void);

} Layout;

typedef struct {

	const char *prop;

	const char *tags;

	Bool isfloating;

} Rule;

typedef struct {

	regex_t *propregex;

	regex_t *tagregex;

} Regs;

/* forward declarations */

static void applyrules(Client *c);

static void arrange(void);

static void attach(Client *c);

static void attachstack(Client *c);

static void ban(Client *c);

static void buttonpress(XEvent *e);

static void checkotherwm(void);

static void cleanup(void);

static void compileregs(void);

static void configure(Client *c);

static void configurenotify(XEvent *e);

static void configurerequest(XEvent *e);

static void destroynotify(XEvent *e);

static void detach(Client *c);

static void detachstack(Client *c);

static void drawbar(void);

static void drawsquare(Bool filled, Bool empty, unsigned long col[ColLast]);

static void drawtext(const char *text, unsigned long col[ColLast]);

static void *emallocz(unsigned int size);

static void enternotify(XEvent *e);

static void eprint(const char *errstr, ...);

static void expose(XEvent *e);

static void floating(void); /* default floating layout */

static void focus(Client *c);

static void focusnext(const char *arg);

static void focusprev(const char *arg);

static Client *getclient(Window w);

static unsigned long getcolor(const char *colstr);

static long getstate(Window w);

static Bool gettextprop(Window w, Atom atom, char *text, unsigned int size);

static void grabbuttons(Client *c, Bool focused);

static unsigned int idxoftag(const char *tag);

static void initfont(const char *fontstr);

static Bool isarrange(void (*func)());

static Bool isoccupied(unsigned int t);

static Bool isprotodel(Client *c);

static Bool isvisible(Client *c);

static void keypress(XEvent *e);

static void killclient(const char *arg);

static void leavenotify(XEvent *e);

static void manage(Window w, XWindowAttributes *wa);

static void mappingnotify(XEvent *e);

static void maprequest(XEvent *e);

static void movemouse(Client *c);

static Client *nexttiled(Client *c);

static void propertynotify(XEvent *e);

static void quit(const char *arg);

static void resize(Client *c, int x, int y, int w, int h, Bool sizehints);

static void resizemouse(Client *c);

static void restack(void);

static void run(void);

static void scan(void);

static void setclientstate(Client *c, long state);

static void setlayout(const char *arg);

static void setmwfact(const char *arg);

static void setup(void);

static void spawn(const char *arg);

static void tag(const char *arg);

static unsigned int textnw(const char *text, unsigned int len);

static unsigned int textw(const char *text);

static void tile(void);

static void togglebar(const char *arg);

static void togglefloating(const char *arg);

static void togglemax(const char *arg);

static void toggletag(const char *arg);

static void toggleview(const char *arg);

static void unban(Client *c);

static void unmanage(Client *c);

static void unmapnotify(XEvent *e);

static void updatebarpos(void);

static void updatesizehints(Client *c);

static void updatetitle(Client *c);

static void view(const char *arg);

static int xerror(Display *dpy, XErrorEvent *ee);

static int xerrordummy(Display *dsply, XErrorEvent *ee);

static int xerrorstart(Display *dsply, XErrorEvent *ee);

static void zoom(const char *arg);

/* variables */

static char stext[256];

static double mwfact;

static int screen, sx, sy, sw, sh, wax, way, waw, wah;

static int (*xerrorxlib)(Display *, XErrorEvent *);

static unsigned int bh, bpos, ntags;

static unsigned int blw = 0;

static unsigned int ltidx = 0; /* default */

static unsigned int nlayouts = 0;

static unsigned int nrules = 0;

static unsigned int numlockmask = 0;

static void (*handler[LASTEvent]) (XEvent *) = {

	[ButtonPress] = buttonpress,

	[ConfigureRequest] = configurerequest,

	[ConfigureNotify] = configurenotify,

	[DestroyNotify] = destroynotify,

	[EnterNotify] = enternotify,

	[LeaveNotify] = leavenotify,

	[Expose] = expose,

	[KeyPress] = keypress,

	[MappingNotify] = mappingnotify,

	[MapRequest] = maprequest,

	[PropertyNotify] = propertynotify,

	[UnmapNotify] = unmapnotify

};

static Atom wmatom[WMLast], netatom[NetLast];

static Bool otherwm, readin;

static Bool running = True;

static Bool *seltags;

static Bool selscreen = True;

static Client *clients = NULL;

static Client *sel = NULL;

static Client *stack = NULL;

static Cursor cursor[CurLast];

static Display *dpy;

static DC dc = {0};

static Window barwin, root;

static Regs *regs = NULL;

/* configuration, allows nested code to access above variables */

#include "config.h"

/* functions*/

static void

applyrules(Client *c) {

	static char buf[512];

	unsigned int i, j;

	regmatch_t tmp;

	Bool matched = False;

	XClassHint ch = { 0 };

	/* rule matching */

	XGetClassHint(dpy, c->win, &ch);

	snprintf(buf, sizeof buf, "%s:%s:%s",

			ch.res_class ? ch.res_class : "",

			ch.res_name ? ch.res_name : "", c->name);

	for(i = 0; i < nrules; i++)

		if(regs[i].propregex && !regexec(regs[i].propregex, buf, 1, &tmp, 0)) {

			c->isfloating = rules[i].isfloating;

			for(j = 0; regs[i].tagregex && j < ntags; j++) {

				if(!regexec(regs[i].tagregex, tags[j], 1, &tmp, 0)) {

					matched = True;

					c->tags[j] = True;

				}

			}

		}

	if(ch.res_class)

		XFree(ch.res_class);

	if(ch.res_name)

		XFree(ch.res_name);

	if(!matched)

		for(i = 0; i < ntags; i++)

			c->tags[i] = seltags[i];

}

static void

arrange(void) {

	Client *c;

	for(c = clients; c; c = c->next)

		if(isvisible(c))

			unban(c);

		else

			ban(c);

	layouts[ltidx].arrange();

	focus(NULL);

	restack();

}

static void

attach(Client *c) {

	if(clients)

		clients->prev = c;

	c->next = clients;

	clients = c;

}

static void

attachstack(Client *c) {

	c->snext = stack;

	stack = c;

}

static void

ban(Client *c) {

	if(c->isbanned)

		return;

	XMoveWindow(dpy, c->win, c->x + 2 * sw, c->y);

	c->isbanned = True;

}

static void

buttonpress(XEvent *e) {

	unsigned int i, x;

	Client *c;

	XButtonPressedEvent *ev = &e->xbutton;

	if(barwin == ev->window) {

		x = 0;

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

			x += textw(tags[i]);

			if(ev->x < x) {

				if(ev->button == Button1) {

					if(ev->state & MODKEY)

						tag(tags[i]);

					else

						view(tags[i]);

				}

				else if(ev->button == Button3) {

					if(ev->state & MODKEY)

						toggletag(tags[i]);

					else

						toggleview(tags[i]);

				}

				return;

			}

		}

		if((ev->x < x + blw) && ev->button == Button1)

			setlayout(NULL);

	}

	else if((c = getclient(ev->window))) {