/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2011 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.operator.clustering;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedList;

/**
 * This class represents a not leaf node of a hierarchical cluster tree.
 * It holds only references on the children and not on the contained examples. Hence contained examples are gathered
 * recursivly from leaf nodes.
 * 
 * @author Sebastian Land
 */
public class HierarchicalClusterNode implements Serializable {
	
	private static final long serialVersionUID = 2249266864895013348L;

	private Collection<HierarchicalClusterNode> subNodes;
	
	private double distance;
	
	private String clusterId;
	
	
	public HierarchicalClusterNode(String clusterId) {
		this.clusterId = clusterId;
		this.subNodes = new ArrayList<HierarchicalClusterNode>();
	}

	public HierarchicalClusterNode(int clusterId, double distance) {
		this(clusterId + "");
		this.distance = distance;
	}

	public HierarchicalClusterNode(String clusterId, double distance) {
		this(clusterId);
		this.distance = distance;
	}
	
	/**
	 * Get all children of this node.
	 * 
	 * @return Iterator of ClusterNode
	 */
	public Collection<HierarchicalClusterNode> getSubNodes() {
		return subNodes;
	}

	/**
	 * Get the number of subnodes.
	 * 
	 * @return the number of subnodes.
	 */
	public int getNumberOfSubNodes() {
		return subNodes.size();
	}

	/**
	 * Get the weight of this node. This might represent similarity to another 
	 * cluster or something else.
	 * 
	 * @return double
	 */
	public double getDistance() {
		return distance;
	}

	/**
	 * Get all objects (as representend by their IDs) in the subtree including the objects located directly at this node. Note that objects can occur
	 * more than once.
	 * 
	 * @return Iterator of String
	 */
	public Collection<Object> getExampleIdsInSubtree() {
		Collection<Object> examples = new LinkedList<Object>();
		for (HierarchicalClusterNode subNode: subNodes) {
			examples.addAll(subNode.getExampleIdsInSubtree());
		}
		return examples;
	}

	/**
	 * Returns the number of objects in the subtree including the objects at the current node. Note that objects can occur more than once and are
	 * counted as such. To get the number of distinct objects use the getObjectsInSubtree function first and use the resulting list to calculate the
	 * number of distinct objects.
	 * 
	 * @return number of objects
	 */
	public int getNumberOfExamplesInSubtree() {
		int subtreeSum = 0;
		for (HierarchicalClusterNode subNode: subNodes) {
			subtreeSum += subNode.getNumberOfExamplesInSubtree();
		}
		return subtreeSum;
	}

	public void addSubNode(HierarchicalClusterNode node) {
		subNodes.add(node);
	}
	
	public int getTotalNumberOfSubnodes() {
		if (getNumberOfSubNodes() == 0) {
			return 1;
		} else {
			int count = 0;
			for (HierarchicalClusterNode child : getSubNodes()) {
				count += child.getTotalNumberOfSubnodes();
			}
			count++;
			return count;
		}
	}

	public String getClusterId() {
		return clusterId;
	}
	
	@Override
	public String toString() {
		return clusterId + ":" + getNumberOfExamplesInSubtree() + " (" + getDistance() + ")";
	}
}