/*
 *  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.clusterer;

import java.util.List;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.Tools;
import com.rapidminer.example.table.AttributeFactory;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.clustering.ClusterModel;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeInt;
import com.rapidminer.tools.Ontology;
import com.rapidminer.tools.RandomGenerator;
/**
 * Returns a random clustering. Note that this algorithm does not garantuee that all clusters are non-empty.
 * This operator will create a cluster attribute if not present yet.
 * 
 * @author Sebastian Land
 */

public class RandomClustering extends RMAbstractClusterer {

	public static final String PARAMETER_NUMBER_OF_CLUSTERS = "number_of_clusters";


	public RandomClustering(OperatorDescription description) {
		super(description);
	}


	@Override
	public ClusterModel generateClusterModel(ExampleSet exampleSet) throws OperatorException {
		// checking and creating ids if necessary
		Tools.checkAndCreateIds(exampleSet);

		// generating assignment
		RandomGenerator random = RandomGenerator.getRandomGenerator(this);
		int clusterAssignments[] = new int[exampleSet.size()];
		int k = getParameterAsInt(PARAMETER_NUMBER_OF_CLUSTERS);
		for (int i = 0; i < exampleSet.size(); i++) {
			clusterAssignments[i] = random.nextInt(k);
		}

		ClusterModel model = new ClusterModel(exampleSet, k, getParameterAsBoolean(RMAbstractClusterer.PARAMETER_ADD_AS_LABEL), getParameterAsBoolean(RMAbstractClusterer.PARAMETER_REMOVE_UNLABELED));
		model.setClusterAssignments(clusterAssignments, exampleSet);

		// generating cluster attribute
		if (addsClusterAttribute()) {
			Attribute cluster = AttributeFactory.createAttribute("cluster", Ontology.NOMINAL);
			exampleSet.getExampleTable().addAttribute(cluster);
			exampleSet.getAttributes().setCluster(cluster);
			int i = 0;
			for (Example example: exampleSet) {
				example.setValue(cluster, "cluster_" + clusterAssignments[i]);
				i++;
			}
		}
		return model;
	}

	@Override
	public List<ParameterType> getParameterTypes() {
		List<ParameterType> types = super.getParameterTypes();

		ParameterType type = new ParameterTypeInt(PARAMETER_NUMBER_OF_CLUSTERS, "Specifies the desired number of clusters.", 2, Integer.MAX_VALUE, 3);
		type.setExpert(false);
		types.add(type);

		types.addAll(RandomGenerator.getRandomGeneratorParameters(this));
		return types;
	}
}