// Simple turtle graphics package
// Create by Lyn on 3/14/97
// Updated on 11/3/97
// Simplified by Randy for CS111 presentation 4/5/05
// Safari bug fixed.  See TurtleWorld.java.  -Mark 6 Dec 2005

import java.awt.*;       // Import Abstract Window Toolkit

public class Turtle {
     
     private double x;             // x position of turtle
     private double y;             // y position of turtle
     private double heading;       // heading of turtle, in degrees
     private boolean pendown;      // is turtle in drawing mode?
     private Color color;          // Red is the default 
     private Graphics gfx;         // graphics with which turtle draws
     private Rectangle bounds;     // bounds of drawing surface
     
     public Turtle() 
     {
          color = Color.red; 
          this.x = 0.0;
          this.y = 0.0;
          this.heading = 0.0;
          this.pendown = true;
          ensureGraphics();
     }
     
     // Forward
     public void fd(double dist) 
     {
          double rads = degreesToRadians(heading);
          this.moveTo(x + (dist * Math.cos(rads)), y + (dist * Math.sin(rads)));
     }
     public void fd (int dist) 
     {
          fd((double) dist);
     }
     // Backward
     public void bd(double dist) 
     {
          this.fd(- dist);
     }
     public void bd (int dist) 
     {
          bd((double) dist);
     }
     // Left 
     public void lt(double degrees) 
     {
          this.heading = heading + degrees;
     }
     public void lt (int degrees) 
     {
          lt((double) degrees);
     }
     // Right 
     public void rt(double angle) 
     {
          this.lt(- angle);
     }
     public void rt (int degrees) 
     {
          rt((double) degrees);
     }
     // Pen Up 
     public void pu() 
     {
          this.pendown = false;
     }
     // Pen Down 
     public void pd() 
     {
          this.pendown = true;
     }
     // Position
     public Point getPosition () 
     {
          return new Point ((int) x, (int) y);
     }
     public void setPosition (Point p) 
     {
          x = (double) p.x;
          y = (double) p.y;
     }
     public void setPosition (int ix, int iy) 
     {
          x = (double) ix;
          y = (double) iy;
     }
     public void setPosition (double dx, double dy) 
     {
          x = dx;
          y = dy;
     }
     // Heading
     public double getHeading () 
     {
          return heading; 
     }
     public void setHeading (double degrees) 
     {
          heading = degrees;
     }
     public void setHeading (int degrees) 
     {
          heading = (double) degrees;
     }
     // Color
     public Color getColor () 
     {
          return color;
     }
     public void setColor (Color c) 
     {
          color = c;
     }
     
     // Other
     public void moveTo(double newx, double newy) 
     {
          // For testing purposes:
          /*
          System.println("Move: heading = " + heading 
                              + "; x = " + x 
                              + "; y = " + y 
                              + "; newx = " + newx
                              + "; newy = " + newy);
          */
          if (pendown) {
               this.gfx.setColor(color);
               this.gfx.drawLine(screenX(x), screenY(y), screenX(newx), screenY(newy));
          }
          x = newx;
          y = newy;
     }
     private void ensureGraphics () 
     {
          this.gfx = TurtleWorld.currentWorld.getTurtleGraphics();
          //System.err.println("My graphics context is:  " + gfx);
          this.bounds = gfx.getClipBounds();
     }
     private int screenX(double xcoord) 
     {
          if (bounds == null) throw new RuntimeException("bounds is null!");
          return (int) Math.round(bounds.x + (bounds.width / 2) + xcoord);
     }
     private int screenY(double ycoord) 
     {
          return (int) Math.round(bounds.y + (bounds.height / 2) - ycoord);
     }
     private static double degreesToRadians (double degrees) 
     {
          return 2 * Math.PI * (degrees / 360);
     }
}