package org.flexdock.plaf.common.border;

import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Insets;

import javax.swing.border.Border;


public class ShadowBorder implements Border {
   private Insets insets;

   public ShadowBorder() {
	  insets = new Insets(1, 1, 3, 3);
   }

   public Insets getBorderInsets(Component c) {
	  return insets;
   }

   public boolean isBorderOpaque() {
	  // we'll be filling in our own background.
	  return true;
   }

   public void paintBorder(Component c, Graphics g, int x, 
									int y, int w, int h) {
	  // choose which colors we want to use
	  Color bg = c.getBackground();
	  if(c.getParent()!=null)
		 bg = c.getParent().getBackground();
	  Color mid = bg.darker();
	  Color rect = mid.darker();
	  Color edge = average(mid, bg);
      
	  // fill in the corners with the parent-background 
	  // so it looks see-through
	  g.setColor(bg);
	  g.fillRect(0, h-3, 3, 3);
	  g.fillRect(w-3, 0, 3, 3);
	  g.fillRect(w-3, h-3, 3, 3);

	  // draw the outline
	  g.setColor(rect);
	  g.drawRect(0, 0, w - 3, h - 3);

	  // draw the drop-shadow
	  g.setColor(mid);
	  g.drawLine(1, h - 2, w - 2, h - 2);
	  g.drawLine(w - 2, 1, w - 2, h - 2);

	  g.setColor(edge);
	  g.drawLine(2, h - 1, w - 2, h - 1);
	  g.drawLine(w - 1, 2, w - 1, h - 2);
   }
   
   private static Color average(Color c1, Color c2) {
	  int red = c1.getRed() + (c2.getRed() - c1.getRed()) / 2;
	  int green = c1.getGreen() + (c2.getGreen() - c1.getGreen()) / 2;
	  int blue = c1.getBlue() + (c2.getBlue() - c1.getBlue()) / 2;
	  return new Color(red, green, blue);
   }
}