import java.util.StringTokenizer;
import java.text.DecimalFormat;

/** Time class for manipulating times of day
  @author Zachary Scott, Joanne Houlahan
*/
public class Time {

  // Time is stored in military format
  private int hours;
  private int minutes;
  private char meridian;

  public static final DecimalFormat TIMEFMT = new DecimalFormat("00");

  /** Default constructor for Time class 
  */
  public Time () {
    hours = 0;
    minutes = 0;
    meridian = 'a';
  }

  /** Time constructor that takes an input string 
      @param timeString the time string to parse
  */
  public Time (String timeString) {

    StringTokenizer tok = new StringTokenizer(timeString, " :apAP");

    hours = Integer.parseInt(tok.nextToken());
    minutes = Integer.parseInt(tok.nextToken());
    meridian = Character.toLowerCase(timeString.charAt(timeString.length()-1));
	 
    if (meridian == 'p' && hours != 12) hours += 12;
    if (meridian == 'a' && hours == 12) hours = 0;

  }

  /** Time constructor that takes in the time in military format
      @param hrs the hour in military format
      @param mins the minutes past the hour
  */
  public Time (int hrs, int mins) {
  
    hours = hrs;
    minutes = mins;
    meridian = (hrs < 12) ? 'a' : 'p';
  }

  /** Method to return the minutes
      @return the minutes past the hour
  */
  public int getMinutes() {
     return minutes;
  }

  /** Method to return the hour
      @return the hour (0 <= hour <= 23)
  */
  public int getHours() {
    return hours;
  }
  
  /** Method to return whether or not the stored time is in the morning
      @return true if morning, false if afternoon/evening
  */
  public boolean isMorning() {
    return meridian == 'a';
  }
 
  /** Method to return the time elapsed between two Time objects
      @param t the end time
      @return a Time object representing the elapsed time between this 
              and the parameter time
  */
  public Time until(Time t) {
      int tHours = t.getHours();
	  int tMins = t.getMinutes();
	  
	  if (compareTo(t) == 0) return new Time();	// 0:00 difference
	  if (compareTo(t) > 0) {
           tHours += 24; 
	  }
	  
	  int elapsedH = tHours - hours;
	  int elapsedM = tMins - minutes;
	  
	  if (elapsedM < 0) {
		elapsedH--;
		elapsedM += 60;
	  }

	  Time ttime = new Time(elapsedH, elapsedM);
	  return ttime;
  }

  /** Method to compare this Time to another Time
      @param t - the Time object to compare to
      @return 0 if the Times are equal, -1 if this is before t, 
              1 if this is after t
  */
  public int compareTo(Time t) {
	 if (hours < t.hours || (hours == t.hours && minutes < t.minutes)) return -1;
 	 else if (hours > t.hours || (hours == t.hours && minutes > t.minutes)) return 1;
	 else return 0;

/* ALTERNATE VERSION using elapsed time since midnight
	int thiselapsed = hours*60 + minutes;
	int otherelapsed = t.hours*60 + t.minutes;
	return thiselapsed - otherelapsed;
*/
  }

  /** Method to convert this Time object to a string
      @return a String representing the time stored by this Time object
  */
  public String toString() {
	return TIMEFMT.format(hours) + ":" + TIMEFMT.format(minutes);  

/* ALTERNATE VERSION
	String m = (minutes > 9) ? "" + minutes : "0" + minutes;
	String h = (hours > 9) ? "" + hours : "0" + hours; 
	return h + ":" + m;
*/
  }

  public void add(int mins) {
	int elapsed = hours*60 + minutes + mins;
	hours = elapsed / 60;
	minutes = elapsed % 60;
	if (hours >= 24) hours = hours % 24;
	meridian = (hours < 12) ? 'a' : 'p';
  }	

  public int elapsed() {
	return hours*60 + minutes;
  }

}