package horstmann.ch09_animation2;
import java.util.Comparator;
import java.util.concurrent.BlockingQueue;

/**
   This runnable executes a sort algorithm.
   When two elements are compared, the algorithm
   pauses and updates a panel.
 */
public class Sorter implements Runnable
{
  public Sorter(Double[] values, ArrayComponent panel, BlockingQueue<String> queue)
  {
    this.values = values;
    this.panel = panel;
    this.queue = queue;
  }

  public void run()
  {
    Comparator<Double> comp = (d1, d2) -> {
      try
      {
        String command = queue.take();
        if (command.equals("Run"))
        {
          Thread.sleep(DELAY);
          if (!"Step".equals(queue.peek()))
            queue.add("Run");
        }
      }
      catch (InterruptedException exception)
      {
        Thread.currentThread().interrupt();
      }
      panel.setValues(values, d1, d2);
      return d1.compareTo(d2);
    };
    MergeSorter.sort(values, comp);
    panel.setValues(values, null, null);
  }

  private Double[] values;
  private ArrayComponent panel;
  private BlockingQueue<String> queue;
  private static final int DELAY = 100;
}