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

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

String	fallback_resources[] = {
	"*FontList:     *-helvetica-bold-r-*-140-75-*",
	"*background:   grey90",
	"*.ruleText.width: 80",
	NULL
};
XrmOptionDescRec	options[] = {
	{"-mag","*nMag",XrmoptionSepArg,NULL},
	{"-size","*nSize",XrmoptionSepArg,NULL},
	{"-rule","*nRule",XrmoptionSepArg,NULL},
};
#define	N_OPTIONS	3
XtResource	resources[] = {
	{"nMag","NMag",XmRShort,sizeof(short),
	XtOffset(ApplicationDataPtr,mag),XtRImmediate,(XtPointer)4},
	{"nSize","NSIZE",XmRShort,sizeof(short),
	XtOffset(ApplicationDataPtr,size),XtRImmediate,(XtPointer)120},
	{"nRule","NRule",XmRShort,sizeof(short),
	XtOffset(ApplicationDataPtr,rule),XtRImmediate,(XtPointer)30},
};
char	*field, *work;
Display	*dpy = NULL;
GC	gc;
Window	win;
Pixmap pmap;
unsigned short	size;
Pixel	black, white;
int	CurrentRow = 0;
int	Rule;
/* rule 4 (010 goes to 1, else 0)	... simple
   rule 22 (001,100, and 010 goto 1, else 0)
   rule 30 (001, 100, 010, and 011 go to 1, else 0)
   rule 54 (001,100, 010, and 101 go to 1, else 0)
   rule 110 (001,010,011,101,110 go to 1 else 0)	... complex
*/
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 display()
{
	int	i, j;
	if (CurrentRow >= AppData.size) {
		XCopyArea(dpy,pmap,pmap,gc,
			0,AppData.mag,size,size-AppData.mag,0,0);
		CurrentRow = AppData.size - 1;
	}
	for (i = 0; i < AppData.size; i ++) {
		XSetForeground(dpy,gc,(field[i]?white:black));
		if (AppData.mag == 1) XDrawPoint(dpy,pmap,gc,i,CurrentRow);
		else XFillRectangle(dpy,pmap,gc,
			i*AppData.mag,CurrentRow*AppData.mag,
			AppData.mag,AppData.mag);
	}
	XCopyArea(dpy,pmap,win,gc,0,0,size,size,0,0);
	CurrentRow ++;
}
void reset()
{
	int	i;
	for (i = 0; i < AppData.size; i ++) field[i] = lrand48() & 1;
	CurrentRow = 0;
	XSetForeground(dpy,gc,black);
	XFillRectangle(dpy,pmap,gc,0,0,size,size);
	display();
}
Boolean work_one_step(cl)
XtPointer	cl;
{
	int	i, left, right, s;
	char	*p;
	for (i = 0; i < AppData.size; i ++) {
		left = (i + AppData.size-1) % AppData.size;
		right = (i + 1) % AppData.size;
		s = (field[left] << 2) | (field[i] << 1) | field[right];
		work[i] = (Rule & (1 << s))? 1 : 0;
	}
	p = work; work = field; field = p;
	display();
	return !Running;
}
void RedrawCB(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);
}
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(StopButton,XmNsensitive,False,NULL);
	XtVaSetValues(StartButton,XmNsensitive,True,NULL);
}
void StepCB(w,cl,cd) Widget w; XtPointer cl,cd;
{
	StopCB(w,cl,cd);
	XtAppAddWorkProc(app_con,work_one_step,NULL);
}
void NewRuleCB(w,cl,cd) Widget w; XtPointer cl,cd;
{
	char	*v;
	XtVaGetValues(rule_text,XmNvalue,&v,NULL);
	if (v) Rule = atoi(v);
}
main(argc,argv)
int	argc;
char	*argv[];
{
	Widget	main_win, menu_bar, ctl, button;
	char	text_value[16];
	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 = (char *)malloc(AppData.size * AppData.size * 2);
	if (!field) { perror("malloc"); exit(1); }
	work = field + AppData.size * AppData.size;
	size = AppData.mag * AppData.size;
	Rule = AppData.rule;
	XtSetArg(args[0],XmNshowSeparator,True);
	XtManageChild(main_win=XmCreateMainWindow(app_sh,"main",args,1));
	XtManageChild(menu_bar=XmCreateMenuBar(main_win,"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);
	XtManageChild(button=XmCreateCascadeButton(menu_bar,"Step",NULL,0));
	XtAddCallback(button,XmNactivateCallback,StepCB,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],XmNorientation,XmHORIZONTAL);
	XtManageChild(ctl=XmCreateRowColumn(main_win,"control",args,1));
	XtManageChild(XmCreateLabel(ctl,"Rule:",NULL,0));
	sprintf(text_value,"%d",Rule);
	XtSetArg(args[0],XmNvalue,text_value);
	XtManageChild(rule_text=XmCreateText(ctl,"ruleText",args,1));
	XtManageChild(button=XmCreatePushButton(ctl,"Apply",NULL,0));
	XtAddCallback(button,XmNactivateCallback,NewRuleCB,NULL);
	XtSetArg(args[0],XmNwidth,size);
	XtSetArg(args[1],XmNheight,size);
	XtManageChild(draw=XmCreateDrawingArea(main_win,"field",args,2));
	XtVaSetValues(main_win,XmNcommandWindow,ctl,XmNworkWindow,draw,NULL);
	XtRealizeWidget(app_sh);
	setup_draw_info();
	reset();
	XtAddCallback(draw,XmNexposeCallback,RedrawCB,NULL);
	XtAppMainLoop(app_con);
}