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

/**
 * A class which animates a node from one position to
 * another along a straight path.
 *
 * @see Node
 * @see AnimationManager
 * @author Michael Shilman (michaels@eecs.berkeley.edu)
 * @version $Id$
 */
public class MoveAction extends AnimationAction {
	/**
	 * The node that is being animated.
	 */
	Node node;
	
	/**
	 * The initial X coordinate of the node when the action
	 * is instantiated.
	 */
	double startX;
	
	/**
	 * The initial Y coordinate of the node when the action
	 * is instantiated.
	 */
	double startY;
	
	/**
	 * The target X coordinate for the node.
	 */
	double finishX;
	
	/**
	 * The target Y coordinate for the node.
	 */
	double finishY;
	
	/**
	 * 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 move it
	 * to the specified position.
	 *
	 * @param n		 The node to animate.
	 * @param x	 	 The final X coordinate.
	 * @param y		 The final Y coordinate.
	 * @param dt	 The duration of the move.
	 */
	public MoveAction(Node n, double x, double y, int dt) {
		node = n;
		startTime = System.currentTimeMillis();
		finishTime = startTime + dt;
		startX = n.x;
		startY = n.y;
		finishX = x;
		finishY = y;
	}

	/**
	 * 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.x = finishX;//XXX
			node.y = finishY;//XXX
			//System.out.println("done!");
			return true; //we're done
		}
		else {
			//interpolate between the two
			double t = ((double)(currentTime - startTime)) /
						((double)(finishTime - startTime));
			node.x = (startX + (t * (finishX - startX)));
			node.y = (startY + (t * (finishY - startY)));
			//System.out.println("working... " + t + ", " + node.x + ", " + node.y);
			return false; //we're not done
		}
	}
}