/* (C)opyright MMVI-MMVII Anselm R. Garbe <garbeam at gmail dot com>

 * See LICENSE file for 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.c:main().

 */

#include "config.h"

#include <X11/Xlib.h>

/* mask shorthands, used in event.c and client.c */

#define BUTTONMASK		(ButtonPressMask | ButtonReleaseMask)

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

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

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

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

typedef union {

	const char *cmd;

	int i;

} Arg; /* argument type */

typedef struct {

	int ascent;

	int descent;

	int height;

	XFontSet set;

	XFontStruct *xfont;

} Fnt;

typedef struct {

	int x, y, w, h;

	unsigned long norm[ColLast];

	unsigned long sel[ColLast];

	Drawable drawable;

	Fnt font;

	GC gc;

} DC; /* draw context */

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, minay, maxax, maxay;

	long flags; 

	unsigned int border;

	Bool isbanned, isfixed, ismax, isversatile;

	Bool *tags;

	Client *next;

	Client *prev;

	Client *snext;

	Window win;

};

typedef struct {

	const char *symbol;

	void (*arrange)(void);

} Layout;

extern const char *tags[];			/* all tags */

extern char stext[256];				/* status text */

extern int screen, sx, sy, sw, sh;		/* screen geometry */

extern int wax, way, wah, waw;			/* windowarea geometry */

extern unsigned int bh, blw;			/* bar height, bar layout label width */

extern unsigned int master, nmaster;		/* master percent, number of master clients */

extern unsigned int ntags, numlockmask;		/* number of tags, dynamic lock mask */

extern void (*handler[LASTEvent])(XEvent *);	/* event handler */

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

extern Bool running, selscreen, *seltag;	/* seltag is array of Bool */

extern Client *clients, *sel, *stack;		/* global client list and stack */

extern Cursor cursor[CurLast];

extern DC dc;					/* global draw context */

extern Display *dpy;

extern Layout *lt;

extern Window root, barwin;

/* client.c */

extern void configure(Client *c);		/* send synthetic configure event */

extern void focus(Client *c);			/* focus c, c may be NULL */

extern void focusnext(Arg *arg);		/* focuses next visible client, arg is ignored  */

extern void focusprev(Arg *arg);		/* focuses previous visible client, arg is ignored */

extern void killclient(Arg *arg);		/* kill c nicely */

extern void manage(Window w, XWindowAttributes *wa);	/* manage new client */

extern Client *nexttiled(Client *c);		/* returns tiled successor of c */

extern void resize(Client *c, int x, int y,

		int w, int h, Bool sizehints);	/* resize with given coordinates c*/

extern void updatesizehints(Client *c);		/* update the size hint variables of c */

extern void updatetitle(Client *c);		/* update the name of c */

extern void unmanage(Client *c);		/* destroy c */

extern void zoom(Arg *arg);			/* zooms the focused client to master area, arg is ignored */

/* event.c */

extern void grabkeys(void);			/* grab all keys defined in config.h */

/* main.c */

extern void drawstatus(void);			/* draw the bar */

extern unsigned int textw(const char *text);	/* return the width of text in px*/

extern void quit(Arg *arg);			/* quit dwm nicely */

extern void sendevent(Window w, Atom a, long value);	/* send synthetic event to w */

extern int xerror(Display *dsply, XErrorEvent *ee);	/* dwm's X error handler */

/* screen.c */

extern void compileregs(void);			/* initialize regexps of rules defined in config.h */

extern void incnmaster(Arg *arg);		/* increments nmaster with arg's index value */

extern void initlayouts(void);			/* initialize layout array */

extern Bool isvisible(Client *c);		/* returns True if client is visible */

extern void resizemaster(Arg *arg);		/* resizes the master percent with arg's index value */

extern void restack(void);			/* restores z layers of all clients */

extern void settags(Client *c, Client *trans);	/* sets tags of c */

extern void tag(Arg *arg);			/* tags c with arg's index */

extern void toggleversatile(Arg *arg);		/* toggles focusesd client between versatile/and non-versatile state */

extern void toggletag(Arg *arg);		/* toggles c tags with arg's index */

extern void toggleview(Arg *arg);		/* toggles the tag with arg's index (in)visible */

extern void versatile(void);			/* arranges all windows versatile */

extern void view(Arg *arg);			/* views the tag with arg's index */

/* util.c */

extern void *emallocz(unsigned int size);	/* allocates zero-initialized memory, exits on error */

extern void eprint(const char *errstr, ...);	/* prints errstr and exits with 1 */

extern void spawn(Arg *arg);			/* forks a new subprocess with to arg's cmd */