// 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 + Integer.hashCode (month);
                hash = 31*hash + Integer.hashCode (day);
                hash = 31*hash + Integer.hashCode (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);
//              }
        }

}