#include	<stdio.h>
#include	<Xm/MainW.h>
#include	<Xm/DrawingA.h>
#include	<Xm/RowColumn.h>
#include	<Xm/CascadeB.h>

XtAppContext	app_con;
Widget	app_sh, draw, StartButton, StopButton;
Boolean	Running = False;
typedef	struct { short mag, size; } ApplicationData, *ApplicationDataPtr;
ApplicationData AppData;

String	fallback_resources[] = {
	"*FontList:     *-helvetica-bold-r-*-140-75-*",
	"*background:   grey90",
	NULL
};
XrmOptionDescRec	options[] = {
	{"-mag","*nMag",XrmoptionSepArg,NULL},
	{"-size","*nSize",XrmoptionSepArg,NULL}
};
#define	N_OPTIONS	2
XtResource	resources[] = {
	{"nMag","NMag",XmRShort,sizeof(short),
	XtOffset(ApplicationDataPtr,mag),XtRImmediate,(XtPointer)4},
	{"nSize","NSIZE",XmRShort,sizeof(short),
	XtOffset(ApplicationDataPtr,size),XtRImmediate,(XtPointer)100},
};
unsigned char	*field, *work;
Display	*dpy = NULL;
GC	gc;
Window	win;
Pixmap pmap;
Pixel	black, white;
unsigned short	size;

void setup_draw_info()
{
	dpy = XtDisplay(app_sh);
	gc = DefaultGC(dpy,0);
	win = XtWindow(draw);
	pmap = XCreatePixmap(dpy,win,size,size,DefaultDepth(dpy,0));
	black = BlackPixel(dpy,0);
	white = WhitePixel(dpy,0);
}
void redisplay()
{
	int	i, j;
	XSetForeground(dpy,gc,white);
	XFillRectangle(dpy,pmap,gc,0,0,size,size);
	XSetForeground(dpy,gc,black);
	for (i = 0; i < AppData.size; i ++) for (j = 0; j < AppData.size; j ++)
	if (field[i*AppData.size+j]) {
		if (AppData.mag == 1) XDrawPoint(dpy,pmap,gc,i,j);
		else XFillRectangle(dpy,pmap,gc,
			i*AppData.mag,j*AppData.mag,AppData.mag,AppData.mag);
	}
	XCopyArea(dpy,pmap,win,gc,0,0,size,size,0,0);
	XFlush(dpy);
}
void reset()
{
	int	i;
	for (i = 0; i < AppData.size * AppData.size; i ++)
		field[i] = lrand48() & 1;
	redisplay();
}
Boolean work_one_step(cl)
XtPointer	cl;
{
	int	i, j, i_pre, i_post, j_pre, j_post;
	if (!Running) return True;
	for (i = 0; i < AppData.size; i ++) {
		i_pre = (i + AppData.size-1) % AppData.size;
		i_post = (i + 1) % AppData.size;
		for (j = 0; j < AppData.size; j ++) {
			j_pre = (j + AppData.size-1) % AppData.size;
			j_post = (j + 1) % AppData.size;
			work[i*AppData.size+j]
			= field[i_pre*AppData.size+j_pre]
			+ field[i_pre*AppData.size+j]
			+ field[i_pre*AppData.size+j_post]
			+ field[i*AppData.size+j_pre]
			+ field[i*AppData.size+j_post]
			+ field[i_post*AppData.size+j_pre]
			+ field[i_post*AppData.size+j]
			+ field[i_post*AppData.size+j_post];
		}
	}
	for (i = 0; i < AppData.size * AppData.size; i ++) {
		if (work[i] == 3) field[i] = '\001';
		else if (work[i] != 2) field[i] = '\0';
	}
	redisplay();
	return !Running;
}
void ResetCB(w,cl,cd) Widget w; XtPointer cl,cd; { reset(); }
void QuitCB(w,cl,cd) Widget w; XtPointer cl,cd; { exit(0);}
void StartCB(w,cl,cd) Widget w; XtPointer cl,cd;
{
	Running = True;
	XtAppAddWorkProc(app_con,work_one_step,NULL);
	XtVaSetValues(StartButton,XmNsensitive,False,NULL);
	XtVaSetValues(StopButton,XmNsensitive,True,NULL);
}
void StopCB(w,cl,cd) Widget w; XtPointer cl,cd;
{
	Running = False;
	XtVaSetValues(StartButton,XmNsensitive,True,NULL);
	XtVaSetValues(StopButton,XmNsensitive,False,NULL);
}
void RedisplayCB(w,cl,cd) Widget w; XtPointer cl,cd;
{
	XmDrawingAreaCallbackStruct *d = (XmDrawingAreaCallbackStruct *)cd;
	XExposeEvent   *e = &(d->event->xexpose);
	XCopyArea(dpy,pmap,win,gc,e->x,e->y,e->width,e->height,e->x,e->y);
}
main(argc,argv)
int	argc;
char	*argv[];
{
	Widget	main_win, menu_bar, button;
	Arg	args[2];
	app_sh = XtAppInitialize(&app_con,"Life Game",options,N_OPTIONS,
		&argc,argv,fallback_resources,NULL,0);
	XtGetApplicationResources(app_sh,(XtPointer)&AppData,resources,
		XtNumber(resources),NULL,0);
	if (AppData.mag < 1) AppData.mag = 1;
	if (AppData.size < 20) AppData.size = 20;
	field = (unsigned char *)malloc(AppData.size * AppData.size * 2);
	if (!field) { perror("malloc"); exit(1); }
	work = field + AppData.size * AppData.size;
	size = AppData.mag * AppData.size;
	XtManageChild(main_win=XmCreateMainWindow(app_sh,"main_window",NULL,0));
	XtManageChild(menu_bar=XmCreateMenuBar(main_win,"menu_bar",NULL,0));
	XtManageChild(button=XmCreateCascadeButton(menu_bar,"Quit",NULL,0));
	XtAddCallback(button,XmNactivateCallback,QuitCB,NULL);
	XtManageChild(button=XmCreateCascadeButton(menu_bar,"Reset",NULL,0));
	XtAddCallback(button,XmNactivateCallback,ResetCB,NULL);
	StartButton = XmCreateCascadeButton(menu_bar,"Start",NULL,0);
	XtManageChild(StartButton);
	XtAddCallback(StartButton,XmNactivateCallback,StartCB,NULL);
	XtSetArg(args[0],XmNsensitive,False);
	StopButton = XmCreateCascadeButton(menu_bar,"Stop",args,1);
	XtManageChild(StopButton);
	XtAddCallback(StopButton,XmNactivateCallback,StopCB,NULL);
	XtSetArg(args[0],XmNwidth,size);
	XtSetArg(args[1],XmNheight,size);
	XtManageChild(draw=XmCreateDrawingArea(main_win,"field",args,2));
	XtRealizeWidget(app_sh);
	setup_draw_info();
	XtAddCallback(draw,XmNexposeCallback,RedisplayCB,NULL);
	reset();
	XtAppMainLoop(app_con);
}