package gr.xfrag.swing;

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

import javax.swing.JLabel;

/**
 * <p>Title: FadeOnChangeLabel </p>
 *
 * <p>Description: A label that animates when it's text value change.</p>
 *
 * <p>Copyright: Copyright (c) 2006 - 2007</p>
 *
 * @author Chris Fragoulides
 * @version 1.0
 */
public class FadeOnChangeLabel
extends JLabel implements Runnable{
	/** 
	 * The last value of the label.
	 */
	private String lastValue = "";
	/** 
	 * True when an animation is in progress. 
	 */
	private boolean animating = false;
	/** 
	 * Fade value.
	 */
	private float fade = 0;
	/**
	 * Initial fade value.
	 */
	private float initFade = .5f;
	/** 
	 * This variable controls how match we 
	 * will fade in each animation loop. 
	 */
	private float fadeStep = -0.1f;
	/**
	 * Red component of the fade color.
	 */
	private float red = 0.6f;
	/**
	 * Green component of the fade color.
	 */
	private float green = 0.6f;
	/**
	 * Blue component of the fade color.
	 */
	private float blue = 1f;
	/**
	 * When a fade is initiated, the label will have this color.
	 */ 
	private Color fadeColor = new Color(red,green,blue,fade);
	/**
	 * Flag to control the fade process.
	 */ 
	private boolean paintCalled = false;
	/**
	 * If this label doesn't control it's painting, we must set
	 * the Container responsible for it. 
	 */
	private Container repaintCont = null;

	/**
	 * Constructor. It contains only a call to setOpaque(),
	 * because we want the color changes to be visible.
	 */
	public FadeOnChangeLabel(){
		setOpaque(true);
	}
	
	/**
	 * Sets animation parameters. Will only accept values in the
	 * range [0,1] for color components and initial fade,
	 * and in (-1,0) for fade step.
	 * @param r - float value of the red color component.
	 * @param g	- float value of the green color component.
	 * @param b	- float value of the blue color component.
	 * @param fStep	- float value of the fade step.
	 * @param iFade	- float value of the initial fade.
	 */
	public void setParams(float r, float g, float b,
							float fStep, float iFade){
		if(r >= 0 && r <= 1)		red = r;
		if(g >= 0 && g <= 1)		green = g;
		if(b >= 0 && b <= 1)		blue = b;
		if(fStep > 0 && fStep < 1)	fadeStep = fStep;
		if(iFade >= 0 && iFade <= 1)initFade = iFade;
	}
	
	/**
	 * Sets the Container that controls this label's painting.
	 * Call this method if the label is a child component of a container
	 * that does not control the painting process.
	 * @param c - Container.
	 */
	public void setRepaintContainer(Container c){
		repaintCont = c;
	}

	/**
	 * Sets the text, and initiates the animation if the 
	 * new value is different that the old one.
	 */
	public void setText(String text){
		super.setText(text);
		if (!text.equals(lastValue)){
			lastValue = text;
			animate();
		}
	}

	/**
	 * Override paintComponent to make it fulfil our needs.
	 */
	public void paintComponent(Graphics g){
		// Let the Label perform its normal painting.
		super.paintComponent(g);
		// Now make the fade effect.
		if(fade != 0){
			Insets i = this.getInsets();
			g.setColor(fadeColor);
			g.fillRect(i.left, i.top, 
					getWidth()-i.left-i.right, 
					getHeight()-i.top-i.bottom);
		}
		// paintComponent() called, we can continue to the next
		// animation frame.
		paintCalled = true;
	}

	/**
	 * Initiates the animation Thread.
	 */
	private void animate() {
		// Only animate if there's not another animation in progress
		// and this Label is actually added to a parent Container, i.e.
		// if it is visible.
		if(!animating && this.getParent()!=null){
			Thread t = new Thread(this);
			t.start();
		}
	}
	
	/**
	 * The core of the animation.
	 */
	public void run() {
		animating = true;
		fade = initFade;
		try {
			while (fade!=0) {
				fadeColor = new Color(red,green,blue,fade);
				fade += fadeStep;
				if (fade < 0) {
					fade = 0;
				}
				paintCalled = false;
				if(repaintCont == null) 
					repaint(); // This label controls it's painting.
				else 
					repaintCont.repaint(); // Ask the container to repaint.
				// Now wait until paintComponent() gets called.
				while(!paintCalled && fade!=0){
					Thread.sleep(100);
				}
			}
			animating = false;
		}
		catch (Exception e) {
			animating = false;
			System.out.println("FadeOnChangeLabel encountered an error: "
					+ e.getMessage());
		}
	}

}