/* 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 a bit array to indicate the tags of a

 * client.

 *

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

 *

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

 */

#include <errno.h>

#include <stdarg.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/select.h>

#include <sys/types.h>

#include <sys/wait.h>

#include <X11/cursorfont.h>

#include <X11/keysym.h>

#include <X11/Xatom.h>

#include <X11/Xlib.h>

#include <X11/Xproto.h>

#include <X11/Xutil.h>

#ifdef XINERAMA

#include <X11/extensions/Xinerama.h>

#endif

/* macros */

#define BUTTONMASK              (ButtonPressMask|ButtonReleaseMask)

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

#define INRECT(X,Y,RX,RY,RW,RH) ((X) >= (RX) && (X) < (RX) + (RW) && (Y) >= (RY) && (Y) < (RY) + (RH))

#define ISVISIBLE(x)            (x->tags & tagset[seltags])

#define LENGTH(x)               (sizeof x / sizeof x[0])

#define MAX(a, b)               ((a) > (b) ? (a) : (b))

#define MIN(a, b)               ((a) < (b) ? (a) : (b))

#define MAXTAGLEN               16

#define MOUSEMASK               (BUTTONMASK|PointerMotionMask)

#define TAGMASK                 ((int)((1LL << LENGTH(tags)) - 1))

#define TEXTW(x)                (textnw(x, strlen(x)) + dc.font.height)

/* enums */

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 */

enum { ClkTagBar, ClkLtSymbol, ClkStatusText, ClkWinTitle,

       ClkClientWin, ClkRootWin, ClkLast };             /* clicks */

typedef union {

	int i;

	unsigned int ui;

	float f;

	void *v;

} Arg;

typedef struct {

	unsigned int click;

	unsigned int mask;

	unsigned int button;

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

	const Arg arg;

} Button;

typedef struct Client Client;

struct Client {

	char name[256];

	float mina, maxa;

	int x, y, w, h;

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

	int bw, oldbw;

	unsigned int tags;

	Bool isfixed, isfloating, isurgent;

	Client *next;

	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 int mod;

	KeySym keysym;

	void (*func)(const Arg *);

	const Arg arg;

} Key;

typedef struct {

	const char *symbol;

	void (*arrange)(void);

} Layout;

typedef struct {

	const char *class;

	const char *instance;

	const char *title;

	unsigned int tags;

	Bool isfloating;

} Rule;

/* function declarations */

static void applyrules(Client *c);

static void arrange(void);

static void attach(Client *c);

static void attachstack(Client *c);

static void buttonpress(XEvent *e);

static void checkotherwm(void);

static void cleanup(void);

static void clearurgent(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 die(const char *errstr, ...);

static void drawbar(void);

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

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

static void enternotify(XEvent *e);

static void expose(XEvent *e);

static void focus(Client *c);

static void focusin(XEvent *e);

static void focusstack(const Arg *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 void grabkeys(void);

static void initfont(const char *fontstr);

static Bool isprotodel(Client *c);

static void keypress(XEvent *e);

static void killclient(const Arg *arg);

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

static void mappingnotify(XEvent *e);

static void maprequest(XEvent *e);

static void monocle(void);

static void movemouse(const Arg *arg);

static Client *nexttiled(Client *c);

static void propertynotify(XEvent *e);

static void quit(const Arg *arg);

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

static void resizemouse(const Arg *arg);

static void restack(void);

static void run(void);

static void scan(void);

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

static void setlayout(const Arg *arg);

static void setmfact(const Arg *arg);

static void setup(void);

static void spawn(const Arg *arg);

static void tag(const Arg *arg);

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

static void tile(void);

static void togglebar(const Arg *arg);

static void togglefloating(const Arg *arg);

static void toggletag(const Arg *arg);

static void toggleview(const Arg *arg);

static void unmanage(Client *c);

static void unmapnotify(XEvent *e);

static void updatebar(void);

static void updategeom(void);

static void updatesizehints(Client *c);

static void updatetitle(Client *c);

static void updatewmhints(Client *c);

static void view(const Arg *arg);

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

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

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

static void zoom(const Arg *arg);

/* variables */

static char stext[256];

static int screen;

static int sx, sy, sw, sh; /* X display screen geometry x, y, width, height */ 

static int by, bh, blw;    /* bar geometry y, height and layout symbol width */

static int wx, wy, ww, wh; /* window area geometry x, y, width, height, bar excluded */

static unsigned int seltags = 0, sellt = 0;

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

static unsigned int numlockmask = 0;

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

	[ButtonPress] = buttonpress,

	[ConfigureRequest] = configurerequest,

	[ConfigureNotify] = configurenotify,

	[DestroyNotify] = destroynotify,

	[EnterNotify] = enternotify,

	[Expose] = expose,

	[FocusIn] = focusin,

	[KeyPress] = keypress,

	[MappingNotify] = mappingnotify,

	[MapRequest] = maprequest,

	[PropertyNotify] = propertynotify,

	[UnmapNotify] = unmapnotify

};

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

static Bool otherwm;

static Bool running = True;

static unsigned int tagset[] = {1, 1}; /* after start, first tag is selected */

static Client *clients = NULL;

static Client *sel = NULL;

static Client *stack = NULL;

static Cursor cursor[CurLast];

static Display *dpy;

static DC dc = {0};

static Layout *lt[] = { NULL, NULL };

static Window root, barwin;

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

#include "config.h"

/* compile-time check if all tags fit into an unsigned int bit array. */

struct NumTags { char limitexceeded[sizeof(unsigned int) * 8 < LENGTH(tags) ? -1 : 1]; };

/* function implementations */

void

applyrules(Client *c) {

	unsigned int i;

	Rule *r;

	XClassHint ch = { 0 };

	/* rule matching */

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

	for(i = 0; i < LENGTH(rules); i++) {

		r = &rules[i];

		if((!r->title || strstr(c->name, r->title))

		&& (!r->class || (ch.res_class && strstr(ch.res_class, r->class)))

		&& (!r->instance || (ch.res_name && strstr(ch.res_name, r->instance)))) {

			c->isfloating = r->isfloating;

			c->tags |= r->tags & TAGMASK;

		}

	}

	if(ch.res_class)

		XFree(ch.res_class);

	if(ch.res_name)

		XFree(ch.res_name);

	if(!c->tags)

		c->tags = tagset[seltags];

}

void

arrange(void) {

	Client *c;

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

		if(ISVISIBLE(c)) {

			XMoveWindow(dpy, c->win, c->x, c->y);

			if(!lt[sellt]->arrange || c->isfloating)

				resize(c, c->x, c->y, c->w, c->h, True);

		}

		else {

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

		}

	focus(NULL);

	if(lt[sellt]->arrange)

		lt[sellt]->arrange();

	restack();

}

void

attach(Client *c) {

	c->next = clients;

	clients = c;

}

void

attachstack(Client *c) {

	c->snext = stack;

	stack = c;

}

void

buttonpress(XEvent *e) {

	unsigned int i, x, click;

	Arg arg = {0};

	Client *c;

	XButtonPressedEvent *ev = &e->xbutton;

	click = ClkRootWin;

	if(ev->window == barwin) {

		i = x = 0;

		do x += TEXTW(tags[i]); while(ev->x >= x && ++i < LENGTH(tags));

		if(i < LENGTH(tags)) {

			click = ClkTagBar;

			arg.ui = 1 << i;

		}

		else if(ev->x < x + blw)

			click = ClkLtSymbol;

		else if(ev->x > wx + ww - TEXTW(stext))

			click = ClkStatusText;

		else

			click = ClkWinTitle;

	}

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

		focus(c);

		click = ClkClientWin;