package algs12;
import stdlib.*;
import java.util.Arrays;
import java.util.Comparator;

/* ***********************************************************************
 *  Compilation:  javac Interval1D.java
 *  Execution:    java Interval1D
 *
 *  1-dimensional interval data type.
 *
 *************************************************************************/

public class Interval1D {
  public static final Comparator<Interval1D> LEFT_ENDPOINT_ORDER  = new LeftComparator();
  public static final Comparator<Interval1D> RIGHT_ENDPOINT_ORDER = new RightComparator();
  public static final Comparator<Interval1D> LENGTH_ORDER         = new LengthComparator();

  private final double left;
  private final double right;

  public Interval1D(double left, double right) {
    if (left <= right) {
      this.left  = left;
      this.right = right;
    }
    else throw new IllegalArgumentException("Illegal interval");
  }

  // left endpoint
  public double left() {
    return left;
  }

  // right endpoint
  public double right() {
    return right;
  }

  // does this interval intersect that one?
  public boolean intersects(Interval1D that) {
    if (this.right < that.left) return false;
    if (that.right < this.left) return false;
    return true;
  }

  // does this interval contain x?
  public boolean contains(double x) {
    return (left <= x) && (x <= right);
  }

  // length of this interval
  public double length() {
    return right - left;
  }

  // string representation of this interval
  public String toString() {
    return "[" + left + ", " + right + "]";
  }



  // ascending order of left endpoint, breaking ties by right endpoint
  private static class LeftComparator implements Comparator<Interval1D> {
    public int compare(Interval1D a, Interval1D b) {
      if      (a.left  < b.left)  return -1;
      else if (a.left  > b.left)  return +1;
      else if (a.right < b.right) return -1;
      else if (a.right > b.right) return +1;
      else                        return  0;
    }
  }

  // ascending order of right endpoint, breaking ties by left endpoint
  private static class RightComparator implements Comparator<Interval1D> {
    public int compare(Interval1D a, Interval1D b) {
      if      (a.right < b.right) return -1;
      else if (a.right > b.right) return +1;
      else if (a.left  < b.left)  return -1;
      else if (a.left  > b.left)  return +1;
      else                        return  0;
    }
  }

  // ascending order of length
  private static class LengthComparator implements Comparator<Interval1D> {
    public int compare(Interval1D a, Interval1D b) {
      double alen = a.length();
      double blen = b.length();
      if      (alen < blen) return -1;
      else if (alen > blen) return +1;
      else                  return  0;
    }
  }




  // test client
  public static void main(String[] args) {
    Interval1D[] intervals = new Interval1D[4];
    intervals[0] = new Interval1D(15.0, 33.0);
    intervals[1] = new Interval1D(45.0, 60.0);
    intervals[2] = new Interval1D(20.0, 70.0);
    intervals[3] = new Interval1D(46.0, 55.0);

    StdOut.println("Unsorted");
    for (int i = 0; i < intervals.length; i++)
      StdOut.println(intervals[i]);
    StdOut.println();

    StdOut.println("Sort by left endpoint");
    Arrays.sort(intervals, Interval1D.LEFT_ENDPOINT_ORDER);
    for (int i = 0; i < intervals.length; i++)
      StdOut.println(intervals[i]);
    StdOut.println();

    StdOut.println("Sort by right endpoint");
    Arrays.sort(intervals, Interval1D.RIGHT_ENDPOINT_ORDER);
    for (int i = 0; i < intervals.length; i++)
      StdOut.println(intervals[i]);
    StdOut.println();

    StdOut.println("Sort by length");
    Arrays.sort(intervals, Interval1D.LENGTH_ORDER);
    for (int i = 0; i < intervals.length; i++)
      StdOut.println(intervals[i]);
    StdOut.println();
  }
}