/****************************************************************

                      Uebungen zur Vorlesung
		  "Graphische Datenverarbeitung"
                       Sommersemester  1996

       Programm: xdatum.c
       Autor:    Christian Boehm

****************************************************************/

# include <stdio.h>
# include <stdlib.h>
# include <Xm/Xm.h>
# include <Xm/RowColumn.h>
# include <Xm/Label.h>
# include <Xm/PushB.h>

/* Globale Variablen */
	
XtAppContext kontext;        /* Applikations-Umgebung */
Widget LabelWidget ;         /* Zur Ausgabe des Datums */

static char * fallbackRessourcen [] = {
	"*titel.labelString: Datum67890",
	"*exit.labelString: EXIT",
	NULL
} ;

/* Callback-Prozeduren */

void TimerCallb (XtPointer dummy1, XtIntervalId * dummy2)
{
        FILE * pipe ;
	char str [80] ;
	XmString compoundstring ;
	int hor, min, sec, timerval ;
	
	/* Das Datum wird durch Shell-ufruf ermittelt */
	
	pipe = popen ("date +%d.%m.%Y.%H.%M.%S", "r") ;
	fscanf (pipe, "%10s.%d.%d.%d", str, &hor, &min, &sec) ;
	pclose (pipe) ;
	str [10]='\0' ;

	/* Stunden, Minuten und Sekunden zur Ermittlung 
	   des Zeitintervalls bis Mitternacht */

	timerval = 24*3600-(hor*60+min)*60+sec ;
	/* printf ("%d %d %d %d \n", hor, min, sec, timerval) ; */
	compoundstring = XmStringCreateLocalized (str) ;
	XtVaSetValues (LabelWidget, XmNlabelString, compoundstring, NULL) ;
	XmStringFree (compoundstring) ;
	XtAppAddTimeOut (kontext, 1000 * timerval, TimerCallb, (XtPointer)NULL) ;
}

void exitCB (Widget w, XtPointer p1, XtPointer p2)
{
	exit (0) ;
}

void InitWidgetBaum (Widget applShell)
{
	Widget box, exitBt ;
	box = 	      XtCreateManagedWidget ("box", xmRowColumnWidgetClass,
					     applShell, (Arg*)NULL, 0);
	LabelWidget = XtCreateManagedWidget ("titel", xmLabelWidgetClass,
					     box, (Arg*)NULL, 0);
	exitBt =      XtCreateManagedWidget ("exit", xmPushButtonWidgetClass,
					     box, (Arg*)NULL, 0);

	XtAddCallback (exitBt, XmNactivateCallback, exitCB, (XtPointer)NULL);
	TimerCallb ((XtPointer) 0, (XtIntervalId *) 0) ;
}

main (int argc, char ** argv)
{
	Widget       applShell;      /* Applikations-Shell */

	applShell = XtAppInitialize (&kontext, "XDatum",
				     (XrmOptionDescRec*)NULL, 0,
				     &argc, argv, fallbackRessourcen,
				     (Arg*)NULL, 0);

	InitWidgetBaum (applShell);
	XtRealizeWidget (applShell);

	/* Hauptschleife zur Ereignisbehandlung: */
	XtAppMainLoop (kontext);
}