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// Exercise 1.2.19 (Solution published at http://algs4.cs.princeton.edu/)
package algs12;
import java.util.Arrays;
import java.util.Comparator;
import stdlib.*;
/* ***********************************************************************
 *  Compilation:  javac Date.java
 *  Execution:    java Date
 *
 *  An immutable data type for dates.
 *
 *************************************************************************/

public class Date implements Comparable<Date> {
  private static final int[] DAYS = { 0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

  private final int month;   // month (between 1 and 12)
  private final int day;     // day   (between 1 and DAYS[month]
  private final int year;    // year

  // do bounds-checking to ensure object represents a valid date
  public Date(int month, int day, int year) {
    if (!isValid(month, day, year)) throw new Error("Invalid date");
    this.month = month;
    this.day   = day;
    this.year  = year;
  }

  // create new data by parsing from string of the form mm/dd/yy
  public Date(String date) {
    String[] fields = date.split("/");
    if (fields.length != 3) {
      throw new Error("Date parse error");
    }
    month = Integer.parseInt(fields[0]);
    day   = Integer.parseInt(fields[1]);
    year  = Integer.parseInt(fields[2]);
    if (!isValid(month, day, year)) throw new Error("Invalid date");
  }

  public int month() { return month; }
  public int day()   { return day;   }
  public int year()  { return year;  }


  // is the given date valid?
  private static boolean isValid(int m, int d, int y) {
    if (m < 1 || m > 12)      return false;
    if (d < 1 || d > DAYS[m]) return false;
    if (m == 2 && d == 29 && !isLeapYear(y)) return false;
    return true;
  }

  // is y a leap year?
  private static boolean isLeapYear(int y) {
    if (y % 400 == 0) return true;
    if (y % 100 == 0) return false;
    return y % 4 == 0;
  }

  // return the next Date
  public Date next() {
    if (isValid(month, day + 1, year))    return new Date(month, day + 1, year);
    else if (isValid(month + 1, 1, year)) return new Date(month + 1, 1, year);
    else                                  return new Date(1, 1, year + 1);
  }


  // is this Date after b?
  public boolean isAfter(Date b) {
    return compareTo(b) > 0;
  }

  // is this Date a before b?
  public boolean isBefore(Date b) {
    return compareTo(b) < 0;
  }

  // compare this Date to that one
  public int compareTo(Date that) {
    if (this.year  < that.year)  return -1;
    if (this.year  > that.year)  return +1;
    if (this.month < that.month) return -1;
    if (this.month > that.month) return +1;
    if (this.day   < that.day)   return -1;
    if (this.day   > that.day)   return +1;
    return 0;
  }

  // return a string representation of this date
  public String toString() {
    return month + "/" + day + "/" + year;
  }

  // is this Date equal to x?
  public boolean equals(Object x) {
    if (x == this) return true;
    if (x == null) return false;
    if (x.getClass() != this.getClass()) return false;
    Date that = (Date) x;
    return (this.month == that.month) && (this.day == that.day) && (this.year == that.year);
  }

  public int hashCode() {
    int hash = 17;
    hash = 31*hash + month;
    hash = 31*hash + day;
    hash = 31*hash + year;
    return hash;
  }



  // A stupid class!
  private static class MyComp implements Comparator<Date>{
    public int compare (Date o1, Date o2) {
      return o2.compareTo (o1);
    }   
  }
  
  // sample client for testing
  public static void main(String[] args) {
    // using the stupid class:
    Comparator<Date> c1 = new MyComp ();

    // using an inner class:
    Comparator<Date> c2 = new Comparator<Date>() {
      public int compare (Date o1, Date o2) {
        return o2.compareTo (o1);
      }
    };
    
    // using a lambda expression:
    Comparator<Date> c3 = (o1, o2) -> o2.compareTo (o1);  
    
    Date[] dates = new Date[] { new Date(2, 25, 2004), new Date(2, 25, 2003), } ;
    StdOut.println (Arrays.binarySearch (dates, new Date(2, 25, 2003), c1));
    
//    Date today = new Date(2, 25, 2004);
//    StdOut.println(today);
//    for (int i = 0; i < 10; i++) {
//      today = today.next();
//      StdOut.println(today);
//    }
//
//    StdOut.println(today.isAfter(today.next()));
//    StdOut.println(today.isAfter(today));
//    StdOut.println(today.next().isAfter(today));
//
//
//    Date birthday = new Date(10, 16, 1971);
//    StdOut.println(birthday);
//    for (int i = 0; i < 10; i++) {
//      birthday = birthday.next();
//      StdOut.println(birthday);
//    }
  }

}