package username.dates;

/**
 * A variety of utilities to aid in the manipulation of dates.
 *
 * @author Samuel A. Rebelsky
 * @version 1.0 of September 2005
 */
public class DateHelper
{
  // +---------------+-----------------------------------------------------
  // | Static Fields |
  // +---------------+

  /**
   * An array such that months[i] is the name of the ith month.
   */
  static String[] months = new String[] {
    "", "January", "February", "March", "April", "May", "June",
    "July", "August", "September", "October", "November", "December"
  }; // months

  /**
   * The number of days in each month.  
   */
  static int[] daysInMonth = new int[] {
    0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 
  }; // daysInMonth
    
  // +----------------+----------------------------------------------------
  // | Static Methods |
  // +----------------+
 
  /**
   * Get the name of a month.
   */
  public static String nameOfMonth(int month) 
  {
    return months[month];
  } // nameOfMonth(int)
  
  /**
   * Get the number of days in a month.  Returns 0 for month 0.
   */
  public static int daysInMonth(int month) 
  {
    return daysInMonth[month];
  } // daysInMonth(int)

  /**
   * Get the number of a month.  Returns 0 for an unknown name.
   */
  public static int monthNum(String name)
  {
    for (int i = 1; i <= 12; i++) {
      if (months[i].equals(name)) {
        return i;
      } // if
    } // for
    // Whoops.  We failed.
    return 0;
  } // monthNum(String)

  /**
   * Determine the number of days between two dates.
   */
  public static int daysBetween(SimpleDate d1, SimpleDate d2)
  {
     int guess1 = Math.abs(d1.dayOfYear() - d2.dayOfYear());
     int guess2 = 365-guess1;
     if (guess2 < guess1) {
       return guess2;
     }
     else {
       return guess1;
     }
  } // daysBetween(Date, Date)
} // class DateHelper