// ------------------------------------------------------
// imports
// ------------------------------------------------------

import java.awt.event.MouseMotionListener;
import java.awt.event.MouseEvent;
import java.awt.Graphics2D;
import java.awt.Graphics;
import java.awt.Color;

import javax.swing.JPanel;
import java.util.Random;

// ------------------------------------------------------
// Eyes
// ------------------------------------------------------

public class Eyes extends JPanel implements MouseMotionListener
{
   // ------------------------------------------------------
   // Constructor
   // ------------------------------------------------------

   public Eyes()
   {
      addMouseMotionListener(this);
   }

   // ------------------------------------------------------
   // paintComponent - Draw our three sets of eyes
   // ------------------------------------------------------

   public void paintComponent(Graphics g)
   {
      super.paintComponent(g);

      int w = getWidth();
      int h = getHeight();

      int xc = (w / 2);
      int yc = (h / 2);

      int size = Math.min(w, h);

      double r     = .3 * size;
      double angle = 110.0;

      for(int i = 0; i < 3; i ++, angle += 120)
      {
         double radians = Math.toRadians(angle);

         double xValue = xc + r * Math.cos(radians);
         double yValue = yc + r * Math.sin(radians);

         double offset = (.0625 * size);

         // --------------------------------------------
         // Each eye is a circle, 'xFirst' is the center
         // of the left eye, 'xSecond' the center of
         // the right eye
         // --------------------------------------------

         double xFirst  = xValue - offset;
         double xSecond = xValue + offset;

         Color eyeColor = (i == 0 ? BLUE : i == 1 ? BROWN : GREEN);

         drawEyes(g, eyeColor, xFirst, xSecond, yValue, size / 10);
      }
   }

   // ------------------------------------------------------
   // mouseMoved - Pass 'e' on to 'handleMouse'
   // ------------------------------------------------------

   public void mouseMoved(MouseEvent e)
   {
      handleMouse(e);
   }

   // ------------------------------------------------------
   // mouseDragged - Pass 'e' on to 'handleMouse'
   // ------------------------------------------------------

   public void mouseDragged(MouseEvent e)
   {
      handleMouse(e);
   }

   // ------------------------------------------------------
   // r - Return 'value' rounded to the nearest integer
   // ------------------------------------------------------

   private static int r(double value)
   {
      return((int)Math.round(value));
   }

   // ------------------------------------------------------
   // getAngle - Find the angle between (x, y) and the
   //            most recent mouse location
   // ------------------------------------------------------

   private double getAngle(double x, double y)
   {
      double xDelta = (mMouseX - x);
      double yDelta = (mMouseY - y);

      double angle = Math.atan2(yDelta, xDelta);

      return(angle);
   }

   // ------------------------------------------------------
   // handleMouse - Save off the mouse's current location,
   //               this is where our eyes will be looking
   // ------------------------------------------------------

   private void handleMouse(MouseEvent e)
   {

      mMouseX = e.getX();
      mMouseY = e.getY();

      repaint();
   }

   // ------------------------------------------------------
   // doCircle - Draw a circle at (x, y) with 'radius'
   //            and filled (or drawn) based on 'fill' 
   // ------------------------------------------------------

   private static void doCircle(
      double x, double y, double radius, Graphics g, boolean fill 
   )
   {
      int xValue = r(x - radius / 2);
      int yValue = r(y - radius / 2);
      int rValue = r(radius);

      if(fill)
         g.fillOval(xValue, yValue, rValue, rValue);

      else
         g.drawOval(xValue, yValue, rValue, rValue);
   }

   // ------------------------------------------------------
   // drawEyes - Draw two eyes, one at (xFirst, yValue)
   //            the other at (xSecond, yValue) using
   //            'eyeColor' and radius 'r1'
   // ------------------------------------------------------

   private void drawEyes(
      Graphics g,
      Color    eyeColor,
      double   xFirst,
      double   xSecond,
      double   yValue,
      double   r1
   )
   {
      doCircle(xFirst,  yValue, r1, g, false);
      doCircle(xSecond, yValue, r1, g, false);

      double a1 = getAngle(xFirst,  yValue);
      double a2 = getAngle(xSecond, yValue);

      // ----------------------------------
      // The iris's radius and the pupil's
      // ----------------------------------

      double r2 = .4 * r1;
      double r3 = .2 * r1;

      double x1 = xFirst  + r3 * Math.cos(a1);
      double y1 = yValue  + r3 * Math.sin(a1);

      double x2 = xSecond + r3 * Math.cos(a2);
      double y2 = yValue  + r3 * Math.sin(a2);

      // ----------------------------------
      // Draw the two irises, first filled
      // using 'eyeColor' then outlined
      // in black
      // ----------------------------------

      g.setColor(eyeColor);

      doCircle(x1, y1, r2, g, true);
      doCircle(x2, y2, r2, g, true);

      g.setColor(Color.black);

      doCircle(x1, y1, r2, g, false);
      doCircle(x2, y2, r2, g, false);

      // -----------------------
      // Now draw the 2 pupils
      // -----------------------

      doCircle(x1, y1, r3, g, true);
      doCircle(x2, y2, r3, g, true);
   }

   // ------------------------------------------------------
   // Member Variables
   // ------------------------------------------------------

   public static final Color BLUE  = new Color(140, 160, 195);
   public static final Color BROWN = new Color(170, 130, 110);
   public static final Color GREEN = new Color(130, 155, 110);

   private int mMouseX;
   private int mMouseY;
}