//
// StarDate.java:
// StarDate Class for astronomical calculations.
//    Copyright 1996 by Akkana Peck.
//

// package Akk.Astro;

import java.util.Date;

// A date class which can calculate decimal years, and knows how
// to initialize itself from a string with decimal days, e.g.
// "1997 Apr 1.034170"
class StarDate extends Date
{
    StarDate()		{ super(); }
    StarDate(Date d)	{ super(); setTime(d.getTime()); }
    StarDate(String s)	{ setTime(s); }

    void setTime(String s)
    {
	// see if the day is decimal:
	int dot = s.indexOf('.');
	if (dot > 0)
	{
	    String maindate = s.substring(0, dot);
	    String decimal = s.substring(dot);
	    float correction = Float.valueOf(decimal).floatValue()
		* 24*60*60*1000;

	    // This is so stupid -- Date has a ctor to set itself
	    // from a string, but has no way of setting itself
	    // from a string after construction!  Sigh.
	    Date stupid = new Date(maindate);
	    // Now add the appropriate decimal days:
	    setTime(stupid.getTime() + (long)correction);
	}
	else
	{
	    Date stupid = new Date(s);
	    setTime(stupid.getTime());
	}
    }

    public void addDays(int days) {
	setTime(getTime() + days * (24*60*60*1000));
    }

    public double daysSince(StarDate t)
    {
        return ((double)(getTime() - t.getTime())) / (24.*60.*60.*1000.);
    }

    public double decimalYears() {
	// getTime() returns milliseconds Math.since Jan 1, 1970, so:
	return getTime() / 365.242191 / (24*60*60*1000);
    }

    public double getTimeAsDecimalDay() {
        Double doub = new Double((double)getTime() / (24.*60.*60.*1000.));
        System.out.println("doub = " + doub.toString());
        return doub.doubleValue() - doub.intValue();
    }

    public double getJulianDate() {
        return ( daysSince(new StarDate("Jan 1 0:00 PST 1970"))
		+ 2440587.83333333333);
    }

    //
    // toDateString() only prints the date, not day or time:
    //
    public String toDateString()
    {
	String s = super.toString();
	// we only want the second, third, and last words (month day year):
	int firstindex = s.indexOf(' ')+1;
	int index = s.indexOf(' ', firstindex);
	index = s.indexOf(' ', index+1);
	int yearindex = s.lastIndexOf(' ');
	return s.substring(firstindex, index) + s.substring(yearindex);
    }

    //
    // toString() prints the date and time, but not day of the week
    //
    public String toString()
    {
	String s = super.toString();
	// we want everything except the first word:
	int firstindex = s.indexOf(' ')+1;
	return s.substring(firstindex);
    }

    //
    // toJulianString() prints the string value of the julian date;
    // if we rely on Double.toString(), we get scientific notation
    // whether we want it or not.
    //
    public String toJulianString()
    {
	double JD = getJulianDate();
	Long l = new Long((long)JD);
	String decimal = new Double(JD - l.doubleValue()).toString();
	decimal = decimal.substring(decimal.indexOf("."));
	return l.toString() + decimal;
    }
}