// Exercise 2.2.2 (Solution published at http://algs4.cs.princeton.edu/)
package algs24;
import stdlib.*;
import java.awt.Font;
/* ***********************************************************************
 *  Compilation:  javac TraceMerge.java
 *  Execution:    java  TraceMerge input
 *
 *  Mergesort the sequence of strings specified as the command-line
 *  arguments and show the detailed trace.
 *
 *  % java TraceMerge MERGESORTEXAMPLE
 *
 *************************************************************************/

public class XTraceHeap {
  private static int line = 0;

  public static void sort(String[] pq) {
    int N = pq.length;
    for (int k = N/2; k >= 1; k--) {
      sink(pq, k, N);
      draw (pq, N, k); line++;
    }
    while (N > 1) {
      exch(pq, 1, N--);
      sink(pq, 1, N);
      draw (pq, N, 1); line++;
    }
  }

  /* *********************************************************************
   * Helper functions to restore the heap invariant.
   **********************************************************************/

  private static void sink(String[] pq, int k, int N) {
    while (2*k <= N) {
      int j = 2*k;
      if (j < N && less(pq, j, j+1)) j++;
      if (!less(pq, k, j)) break;
      exch(pq, k, j);
      k = j;
    }
  }

  /* *********************************************************************
   * Helper functions for comparisons and swaps.
   * Indices are "off-by-one" to support 1-based indexing.
   **********************************************************************/
  private static boolean less(String[] pq, int i, int j) {
    return pq[i-1].compareTo(pq[j-1]) < 0;
  }

  private static void exch(String[] pq, int i, int j) {
    String swap = pq[i-1];
    pq[i-1] = pq[j-1];
    pq[j-1] = swap;
  }

  // is v < w ?
  private static boolean less(String v, String w) {
    return (v.compareTo(w) < 0);
  }


  // draw the contents of the array
  private static void draw(String[] a, int N, int k) {
    StdDraw.setPenColor(StdDraw.BLACK);
    StdDraw.text(-2.50, line, N  + "");
    StdDraw.text(-1.25, line, k + "");
    for (int i = 0; i < a.length; i++) {
      StdDraw.text(i, line, a[i]);
    }
  }

  // display header
  private static void header(String[] a) {
    int N = a.length;
    StdDraw.setPenColor(StdDraw.BLACK);
    StdDraw.text(N/2, -3, "a[ ]");
    for (int i = 0; i < N; i++)
      StdDraw.text(i, -2, i + "");
    StdDraw.text(-2.50, -2, "N");
    StdDraw.text(-1.25, -2, "k");
    StdDraw.setPenColor(StdDraw.BOOK_RED);
    StdDraw.line(-4, -1.65, N-.5, -1.65);
    StdDraw.setPenColor(StdDraw.BLACK);
    for (int i = 0; i < a.length; i++)
      StdDraw.text(i, -1, a[i]);
  }

  // display footer
  private static void footer(String[] a) {
    int N = a.length;
    StdDraw.setPenColor(StdDraw.BLACK);
    for (int i = 0; i < a.length; i++)
      StdDraw.text(i, line, a[i]);
  }


  // test client
  public static void main(String[] args) {
    args = new String[] { "SORTEXAMPLE" };

    // parse command-line argument as an array of 1-character strings
    String s = args[0];
    int N = s.length();
    String[] a = new String[N];
    for (int i = 0; i < N; i++)
      a[i] = s.substring(i, i+1);

    // set canvas size
    StdDraw.setCanvasSize(30*(N+3), (int) (30*(1.5*N+3)));
    StdDraw.setXscale(-4, N+1);
    StdDraw.setYscale(1.5*N+1, -4);
    StdDraw.setFont(new Font("SansSerif", Font.PLAIN, 13));

    // display the header
    header(a);

    // sort the array and display trace
    sort(a);

    // display the footer
    footer(a);
  }

}