//  MovingGraphicalObjectsApplet.java  (c) Kari Laitinen

//  http://www.naturalprogramming.com

//  2011-02-10  File created.
//  2011-02-14  Latest modification.

/*  

    It might be best to use the standard Polygon class
    to represent a Triangle. The Polygon class has
    contains() and translate() methods !!!!

*/

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

abstract class GraphicalObject
{
   Point.Double center_point ;

   // object_velocity specifies the number of pixels the object
   // will be moved in a single movement operation.
   double object_velocity   =  4.0 ;
   Color  object_color    =  Color.RED ;


   public Point2D get_center_point()
   {
      return center_point ;
   }

   public void set_color( Color new_color )
   {
     object_color  =  new_color ;
   }

   public void move_right()
   {
      center_point.setLocation( center_point.x + object_velocity,
                                center_point.y ) ;
   }


   public void move_left()
   {
      center_point.setLocation( center_point.x - object_velocity,
                                       center_point.y ) ;
   }

   public void move_up()
   {
      center_point.setLocation( center_point.x,
                                       center_point.y - object_velocity);
   }

   public void move_down()
   {
      center_point.setLocation( center_point.x,
                                       center_point.y + object_velocity);
   }


   abstract public boolean contains_point( Point given_point ) ;


   public void  move_relatively( double movement_in_direction_x,
                                 double movement_in_direction_y )
   {
      center_point.setLocation(
                           center_point.x  +  movement_in_direction_x,
                           center_point.y  +  movement_in_direction_y ) ;
   }

   public void move_to_position( double new_position_x,
                                 double new_position_y )
   {
      center_point.setLocation( new_position_x, new_position_y ) ;
   }

   abstract public void draw( Graphics2D graphics2D ) ;
}


class Triangle extends GraphicalObject
{
   double side_length ;

   Polygon triangle_polygon = new Polygon() ;

   public Triangle( Point.Double given_center_point,
                    double       given_side_length )
   {
      center_point = given_center_point ;
      side_length  = given_side_length ;

      double distance_from_center_point_to_top_point =

                  side_length / ( 2 * Math.cos( Math.PI / 6 ) ) ;


      double triangle_height = Math.cos( Math.PI / 6 ) * side_length ;

      double distance_from_center_point_to_bottom_line =
                  triangle_height - distance_from_center_point_to_top_point ;


      triangle_polygon.addPoint( (int) center_point.x,
                                 (int) ( center_point.y -
                                 distance_from_center_point_to_top_point ) ) ;

      triangle_polygon.addPoint( (int) ( center_point.x + side_length / 2 ),
                                 (int) ( center_point.y +
                                 distance_from_center_point_to_bottom_line ) ) ;

      triangle_polygon.addPoint( (int) ( center_point.x - side_length / 2 ),
                                 (int) ( center_point.y +
                                 distance_from_center_point_to_bottom_line ) ) ;
   }


   public boolean contains_point( Point given_point )
   {
      return ( triangle_polygon.contains( given_point ) ) ;
   }


   public void  move_relatively( double movement_in_direction_x,
                                 double movement_in_direction_y )
   {
      center_point.setLocation(
                           center_point.x  +  movement_in_direction_x,
                           center_point.y  +  movement_in_direction_y ) ;


      // Here we move the triangle by using the translate() method of
      // the Polygon class. A more accurate movement might be achieved
      // by re-creating the Polygon object.


      triangle_polygon.translate( (int) movement_in_direction_x,
                                  (int) movement_in_direction_y ) ;
   }



   public void draw( Graphics2D graphics2D )
   {

      graphics2D.setColor( object_color ) ;

      graphics2D.fill( triangle_polygon ) ;

   }


}


class MovingGraphicalObjectsPanel extends JPanel
                                  implements MouseListener,
                                             MouseMotionListener
{
   int  panel_width, panel_height ;

   GraphicalObject  object_being_moved  =  null ;


   ArrayList<GraphicalObject> movable_objects = new ArrayList<GraphicalObject>();

   Point  previous_mouse_position ;

   public MovingGraphicalObjectsPanel( int given_width,
                                       int given_height )
   {
      panel_width   =  given_width ;
      panel_height  =  given_height ;

      movable_objects.add( new Triangle( new Point.Double( 140, 140 ), 200 ) ) ;
      movable_objects.add( new Triangle( new Point.Double( 140, 340 ), 200 ) ) ;
      movable_objects.add( new Triangle( new Point.Double( 340, 340 ), 200 ) ) ;

      addMouseListener(this);
      addMouseMotionListener(this);
   }

   //  The following dummy methods are needed to satisfy listener
   //  interfaces.

   public void mouseMoved( MouseEvent event ) {}
   public void mouseClicked( MouseEvent event ) {}
   public void mouseEntered( MouseEvent event ) {}
   public void mouseExited( MouseEvent event ) {}

   public void mousePressed( MouseEvent event )
   {
      Point mouse_position  =  event.getPoint() ;

      int object_index  =  movable_objects.size() - 1 ;
   
      boolean search_for_clicked_object_is_ready  =  false ;
   
      while ( search_for_clicked_object_is_ready == false )
      {
         if ( movable_objects.get( object_index ).
                                       contains_point( mouse_position ) )
         {
            object_being_moved  =  movable_objects.get( object_index );

            // We'll remove the clicked object from the list.
            // When we add it to the end of the list, it will be
            // the last object to be drawn.

            movable_objects.remove( object_being_moved ) ; 
            movable_objects.add( object_being_moved ) ;


            //object_being_moved.aktivoi_pallo() ;
            search_for_clicked_object_is_ready  =  true ;
         }
   
         if ( object_index  >  0 )
         {
            object_index -- ;
         }
         else
         {
            search_for_clicked_object_is_ready  =  true ;
         }
      }

      previous_mouse_position  =  mouse_position ;

      repaint() ;
   }

   public void mouseReleased( MouseEvent event )
   {
      if ( object_being_moved  !=  null )
      {
         //object_being_moved.deactivate_ball() ;
         object_being_moved  =  null ;

         repaint() ;
      }
   }

   public void mouseDragged( MouseEvent event )
   {
      if ( object_being_moved  !=  null )
      {
         Point new_mouse_position  =  event.getPoint() ;

         int  mouse_movement_x  =  new_mouse_position.x
                                   -  previous_mouse_position.x ;

         int  mouse_movement_y  =  new_mouse_position.y 
                                   -  previous_mouse_position.y ;

         previous_mouse_position  =  new_mouse_position ;

         object_being_moved.move_relatively( mouse_movement_x, 
                                             mouse_movement_y ) ;

         repaint() ;
      }
   }


   public void paintComponent( Graphics graphics )
   {
      //  The superclass version of paintComponent() must be called first.
      super.paintComponent( graphics ) ;


      Graphics2D  graphics2D  =  (Graphics2D) graphics ;

      for ( GraphicalObject object_to_draw : movable_objects )
      {
         object_to_draw.draw( graphics2D ) ;
      }

      // test_triangle.draw( graphics2D ) ;
   }
}


public class MovingGraphicalObjectsApplet extends JApplet
{
   public void init()
   {
      getContentPane().add( new MovingGraphicalObjectsPanel( getSize().width,
                                                          getSize().height ) ) ; 
   } 
}



/*   A triangle can be drawn as a GeneralPath with the following statements:

      GeneralPath triangle_path = new GeneralPath() ;

      double distance_from_center_point_to_top_point =

                  side_length / ( 2 * Math.cos( Math.PI / 6 ) ) ;


      double triangle_height = Math.cos( Math.PI / 6 ) * side_length ;

      double distance_from_center_point_to_bottom_line =
                  triangle_height - distance_from_center_point_to_top_point ;


      triangle_path.moveTo( (float) center_point.x,
                            (float) ( center_point.y -
                                 distance_from_center_point_to_top_point ) ) ;

      triangle_path.lineTo( (float) ( center_point.x + side_length / 2 ),
                            (float) ( center_point.y +
                                 distance_from_center_point_to_bottom_line ) ) ;

      triangle_path.lineTo( (float) ( center_point.x - side_length / 2 ),
                            (float) ( center_point.y +
                                 distance_from_center_point_to_bottom_line ) ) ;
      triangle_path.closePath() ;


*/