/*
 * Copyright (c) 2010-2022 William Bittle  http://www.dyn4j.org/
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, are permitted 
 * provided that the following conditions are met:
 * 
 *   * Redistributions of source code must retain the above copyright notice, this list of conditions 
 *     and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright notice, this list of conditions 
 *     and the following disclaimer in the documentation and/or other materials provided with the 
 *     distribution.
 *   * Neither the name of the copyright holder nor the names of its contributors may be used to endorse or 
 *     promote products derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR 
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER 
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.dyn4j;

import org.dyn4j.exception.ArgumentNullException;

/**
 * Node class for the {@link BinarySearchTree}.
 * @author William Bittle
 * @version 5.0.0
 * @since 2.2.0
 * @param <E> the comparable type
 */
final class BinarySearchTreeNode<E extends Comparable<E>> implements Comparable<BinarySearchTreeNode<E>> {
	/** The comparable data */
	final E comparable;
	
	// the parent and children will change as the tree evolves
	
	/** The parent node of this node */
	BinarySearchTreeNode<E> parent;
	
	/** The node to the left; the left node is greater than this node */
	BinarySearchTreeNode<E> left;
	
	/** The node to the right; the right node is greater than this node */
	BinarySearchTreeNode<E> right;
	
	/**
	 * Minimal constructor.
	 * @param comparable the comparable object
	 */
	public BinarySearchTreeNode(E comparable) {
		this(comparable, null, null, null);
	}
	
	/**
	 * Full constructor.
	 * @param comparable the comparable object
	 * @param parent the parent node
	 * @param left the left node
	 * @param right the right node
	 * @throws NullPointerException if comparable is null
	 */
	public BinarySearchTreeNode(E comparable, BinarySearchTreeNode<E> parent, BinarySearchTreeNode<E> left, BinarySearchTreeNode<E> right) {
		if (comparable == null) 
			throw new ArgumentNullException("comparable");
		
		this.comparable = comparable;
		this.parent = parent;
		this.left = left;
		this.right = right;
	}
	
	/* (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		return this.comparable.toString();
	}
	
	/* (non-Javadoc)
	 * @see java.lang.Comparable#compareTo(java.lang.Object)
	 */
	@Override
	public int compareTo(BinarySearchTreeNode<E> other) {
		return this.comparable.compareTo(other.comparable);
	}
	
	/**
	 * Returns the comparable object.
	 * @return E
	 */
	public E getComparable() {
		return this.comparable;
	}
	
	/**
	 * Returns true if this node is the left child of
	 * its parent node.
	 * <p>
	 * Returns false if this node does not have a parent.
	 * @return boolean
	 */
	boolean isLeftChild() {
		if (this.parent == null) return false;
		return (this.parent.left == this);
	}
}

