import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.*;
import java.util.*;

/**
   A component that shows a scene composed of shapes.
*/
public class SceneComponent extends JComponent
{
   public SceneComponent()
   {
      shapes = new ArrayList<SceneShape>();

      addMouseListener(new
         MouseAdapter()
         {
            public void mousePressed(MouseEvent event)
            {
               mousePoint = event.getPoint();
               for (SceneShape s : shapes)
               {
                  if (s.contains(mousePoint))
                     s.setSelected(!s.isSelected());
               }
               repaint();
            }
         });

      addMouseMotionListener(new
         MouseMotionAdapter()
         {
            public void mouseDragged(MouseEvent event)
            {
               Point lastMousePoint = mousePoint;
               mousePoint = event.getPoint();
               for (SceneShape s : shapes)
               {
                  if (s.isSelected())
                  {
                     double dx = mousePoint.getX() - lastMousePoint.getX();
                     double dy = mousePoint.getY() - lastMousePoint.getY();
                     s.translate((int) dx, (int) dy);
                  }
               }
               repaint();
            }
         });
   }

   /**
      Adds an shape to the scene.
      @param s the shape to add
   */
   public void add(SceneShape s)
   {
      shapes.add(s);
      repaint();
   }

   /**
      Removes all selected shapes from the scene.
   */
   public void removeSelected()
   {
      for (int i = shapes.size() - 1; i >= 0; i--)
      {
         SceneShape s = shapes.get(i);
         if (s.isSelected()) shapes.remove(i);
      }
      repaint();
   }

   public void paintComponent(Graphics g)
   {
      super.paintComponent(g);
      Graphics2D g2 = (Graphics2D) g;
      for (SceneShape s : shapes)
      {
         s.draw(g2);
         if (s.isSelected())
            s.drawSelection(g2);
      }
   }

   private ArrayList<SceneShape> shapes;
   private Point mousePoint;
}