/* AgeNowApplet: Dispays a person's age on the current date as a string.
   The person's month, day and year of birth must be passed as parameters.
   For example, html to invoke this applet might read:

<APPLET CODE="AgeNowApplet.class" WIDTH=30 HEIGHT=20>
<PARAM NAME=birthYear VALUE="1954">
<PARAM NAME=birthMonth VALUE="4">
<PARAM NAME=birthDay VALUE="30">
*/

import java.awt.Font;
import java.util.Date;
import java.awt.Graphics;

public class AgeNowApplet extends java.applet.Applet {

	Font myFont = new Font("TimesRoman",Font.BOLD,12);
	Date dateNow = new Date();
	int byear,bmonth,bday,yearsOld,monthsOld,daysOld;
	int year,month,day;

	public void init(){

		try { String by = getParameter("birthYear");
		if(by == null)
			byear = 1970;
		else
		        byear = Integer.parseInt(by);
		} catch (NumberFormatException m){
			byear = 1970;}
		try { String bm = getParameter("birthMonth");
		if(bm == null)
			bmonth = 1;
		else 
		        bmonth = Integer.parseInt(bm);
		} catch (NumberFormatException m) {
			bmonth = 1;}
		try { String bd = getParameter("birthDay");
		if(bd == null)
			bday = 1;
		else
			bday = Integer.parseInt(bd);
		} catch (NumberFormatException m) {
			bday = 1;}

                // extract month day and year from date now
		year = dateNow.getYear() + 1900;
		month = dateNow.getMonth()+1;
		day = dateNow.getDate();

		// Compute: case later in year than birthday first.

		if(month > bmonth || (month == bmonth && day >= bday)){
			yearsOld = year - byear;
			monthsOld = month - bmonth -1;
			if(monthsOld >= 0)
				daysOld = day + (MonthLength(bmonth,year)
				                         - bday);
			else    daysOld = day - bday;
		}
		else  {   // earlier in year than birthday	

			yearsOld = year - byear -1;
                        monthsOld = month - bmonth + 11;
			daysOld = day + (MonthLength(bmonth,year-1)
						 - bday);
		}
	}

	public int MonthLength(int monthnumber, int year) {

		int MonthLengths[] = { 31,   // 30 days,
   				       28,   // hath September,
                                       31,   // April,
                                       30,   // June,
				       31,   // and November.
				       30,   // All the rest
  				       31,   // have 31 
                                       31,   // (excepting February,
				       30,   //  alone.)
          			       31,
                                       30,
                                       31};

		if(!isLeapYear(year)) return MonthLengths[monthnumber-1];
                if(month != 2) return MonthLengths[monthnumber-1];
                return 29;
	}

	public boolean isLeapYear(int year) {

	// Is this geek code, or what ?

		if(year % 4 != 0) return false;
        	if(year % 100 != 0) return true;
        	if(year % 400 == 0) return true; // exception to century rule.
        	return false; // generally, centuries are not leap years.
	}

	public void paint(Graphics g) {
		
		g.setFont(myFont);
		g.drawString(Integer.toString(yearsOld) + " years, " +
                             Integer.toString(monthsOld) + " months, and " +
                             Integer.toString(daysOld) + " days ",10,15);
	}
}