package graph.animation;
import graph.*;
import java.awt.Color;

/**
 * A class which fades between the current fill/border
 * colors for a node and a specified set of colors.
 *
 * @see Node
 * @see AnimationManager
 * @author Michael Shilman (michaels@eecs.berkeley.edu)
 * @version $Id$
 */

public class FadeAction extends AnimationAction {
	/**
	 * The node that is being animated.
	 */
	Node node;
	
	/**
	 * The initial fill color of the node when the action
	 * is instantiated.
	 *
	 * @see graph.NodeRep#fill
	 */
	Color startFill = null;
	
	/**
	 * The initial border color of the node when the action
	 * is instantiated.
	 *
	 * @see graph.NodeRep#border
	 */
	Color startBorder = null;
	
	/**
	 * The target fill color for the node.
	 *
	 * @see graph.NodeRep#fill
	 */
	Color finishFill = null;
	
	/**
	 * The target border color for the node.
	 *
	 * @see graph.NodeRep#border
	 */
	Color finishBorder = null;
	
	/**
	 * The start time of the action, for bookkeeping.
	 */
	long startTime;

	/**
	 * The finish time of the action, for bookkeeping.
	 */
	long finishTime;

	/**
	 * A new action on the specified node to morph it into
	 * the specified fill/border colors.
	 *
	 * @param n		 The node to animate.
	 * @param fill	 The final fill color.
	 * @param border The final border color.
	 * @param dt	 The duration of the fade.
	 */
	FadeAction(Node n, Color fill, Color border, int dt) {
		node = n;
		startTime = System.currentTimeMillis();
		finishTime = startTime + dt;
		startFill = ((n.rep.fill == null) ? Color.white : n.rep.fill);
		startBorder = ((n.rep.border == null) ? Color.white : n.rep.border);
		finishFill = fill;
		finishBorder = border;
	}

	/**
	 * Update the animation based on the current time as a linear
	 * interpolation.
	 *
	 * @return <i>true</i> when the action is finished, <i>false</i> otherwise.
	 */
	boolean apply() {
		long currentTime = System.currentTimeMillis();
		if(currentTime >= finishTime) {
			node.rep.fill = finishFill;
			node.rep.border = finishBorder;
			return true; //we're done
		}
		else {
			//interpolate between the two
			double t = ((double)(currentTime - startTime)) /
						((double)(finishTime - startTime));
			double fr = startFill.getRed() + (t * (finishFill.getRed() - startFill.getRed()));
			double fg = startFill.getGreen() + (t * (finishFill.getGreen() - startFill.getGreen()));
			double fb = startFill.getBlue() + (t * (finishFill.getBlue() - startFill.getBlue()));
			node.rep.fill = new Color((int)fr, (int)fg, (int)fb);

			double br = startBorder.getRed() + (t * (finishBorder.getRed() - startBorder.getRed()));
			double bg = startBorder.getGreen() + (t * (finishBorder.getGreen() - startBorder.getGreen()));
			double bb = startBorder.getBlue() + (t * (finishBorder.getBlue() - startBorder.getBlue()));
			node.rep.border = new Color((int)br, (int)bg, (int)bb);

			return false; //we're not done
		}
	}
}