/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2008 by Rapid-I and the contributors
 *
 *  Complete list of developers available at our web site:
 *
 *       http://rapid-i.com
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package com.rapidminer.tools.math.container;

/**
 * The node for a ball tree.
 * 
 * @author Sebastian Land
 * @version $Id: BallTreeNode.java,v 1.4 2008/07/13 23:25:24 ingomierswa Exp $
 *
 * @param <T> This is the type of value with is stored with the points and retrieved on nearest
 * neighbour search
 */
public class BallTreeNode<T> {
	
	private double[] center;
	private double radius;
	private T value;
	
	private BallTreeNode<T> leftChild;
	private BallTreeNode<T> rightChild;
	
	public BallTreeNode(double[] center, double radius, T value) {
		this.center = center;
		this.radius = radius;
		this.value = value;
	}
	
	public BallTreeNode<T> getLeftChild() {
		return leftChild;
	}

	public void setLeftChild(BallTreeNode<T> leftChild) {
		this.leftChild = leftChild;
	}

	public BallTreeNode<T> getRightChild() {
		return rightChild;
	}

	public void setRightChild(BallTreeNode<T> rightChild) {
		this.rightChild = rightChild;
	}

	public double[] getCenter() {
		return center;
	}

	public double getRadius() {
		return radius;
	}


	public void replaceChild(BallTreeNode<T> replaceNode, BallTreeNode<T> replacementNode) {
		if (leftChild == replaceNode)
			leftChild = replacementNode;
		if (rightChild == replaceNode)
			rightChild = replacementNode;
	}

	public String toString() {
		StringBuffer buffer = new StringBuffer();
		buffer.append("[");
		for(double centerDouble: center) {
			buffer.append(centerDouble + "  ");
		}
		buffer.append("]  ");
		buffer.append(radius);
		return buffer.toString();
	}

	public void setRadius(double radius) {
		this.radius = radius;
	}

	public boolean isLeaf() {
		return getLeftChild() == null && getRightChild() == null;
	}

	public boolean hasTwoChilds() {
		return (getLeftChild() != null & getRightChild() != null);
	}

	/**
	 * This method returns the left child if existing or the right child
	 * if left doesnt exist. If right is null either, then null is returned
	 */
	public BallTreeNode<T> getChild() {
		if (getLeftChild() != null) {
			return getLeftChild();
		} else {
			return getRightChild();
		}
	}
	
	public void setChild(BallTreeNode<T> node) {
		if (!hasLeftChild()) {
			setLeftChild(node);
		} else {
			setRightChild(node);
		}
	}
	
	public T getStoreValue() {
		return value;
	}

	public boolean hasLeftChild() {
		return this.leftChild != null;
	}
	
	public boolean hasRightChild() {
		return this.rightChild != null;
	}
}