// AP(r) Computer Science Grid World Case Study:
// The BugRunner class is copyright(c) 2006 College Entrance
// Examination Board (www.collegeboard.com).
//
// This class is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation.
//
// This class is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

import java.awt.Color;

import info.gridworld.actor.Actor;
import info.gridworld.grid.Grid;
import info.gridworld.grid.Location;

public class Shuttle extends Actor
{
   public Shuttle(int n)
   {
      sideLength = n;
      steps = 1;
      setColor(Color.RED);
   }

   public void act()
   {
      if (steps < sideLength)
      {
         move();
         steps++;
      }
      else
      {
         turn();
         steps = 0;
      }
   }
   
   /**
    * Moves this bug forward. The bug may replace other
    * actors or fall outside the grid. Call canMove to check
    * whether it is safe to move.
    */
   public void move()
   {
      Grid<Actor> gr = getGrid();
      Location loc = getLocation();
      Location next = loc.getNeighborLocation(getDirection());
      if (gr.isValid(next))      
         moveTo(next);
      else
         removeSelfFromGrid();
   }      

   public void turn()
   {
      setDirection(getDirection() + Location.HALF_RIGHT);
   }   

   private int steps;
   private int sideLength;
}