/*
 *  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.meta;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Attributes;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.set.SplittedExampleSet;
import com.rapidminer.operator.OperatorChain;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.UserError;
import com.rapidminer.operator.ports.InputPort;
import com.rapidminer.operator.ports.OutputPort;
import com.rapidminer.operator.ports.PortPairExtender;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.ports.metadata.ExampleSetPassThroughRule;
import com.rapidminer.operator.ports.metadata.ExampleSetPrecondition;
import com.rapidminer.operator.ports.metadata.SetRelation;
import com.rapidminer.operator.ports.metadata.SubprocessTransformRule;
import com.rapidminer.parameter.UndefinedParameterError;
import com.rapidminer.tools.Ontology;

/**
 * This operator splits up the input example set according to the clusters and 
 * applies its inner operators <var>number_of_clusters</var> time on copies
 * of its own input. 
 * This requires the example set to have a special cluster attribute which 
 * can be either created by a {@link com.rapidminer.operator.clustering.AbstractClusterer} or 
 * might be declared in the attribute description file that was used when the data was 
 * loaded.
 * 
 * @author Ingo Mierswa
 */
public class ClusterIterator extends OperatorChain {

	private InputPort exampleSetInput = getInputPorts().createPort("example set");
	private OutputPort subsetInnerSource = getSubprocess(0).getInnerSources().createPort("cluster subset");
	private PortPairExtender inputExtender = new PortPairExtender("in", getInputPorts(), getSubprocess(0).getInnerSources());
	private PortPairExtender outputExtender = new PortPairExtender("out", getSubprocess(0).getInnerSinks(), getOutputPorts());

	private int numberOfClusters = 0;

	public ClusterIterator(OperatorDescription description) {
		super(description, "Cluster Iteration");
		inputExtender.start();
		outputExtender.start();
		exampleSetInput.addPrecondition(new ExampleSetPrecondition(exampleSetInput, Ontology.VALUE_TYPE, new String[] { Attributes.CLUSTER_NAME} ));

		getTransformer().addRule(new ExampleSetPassThroughRule(exampleSetInput, subsetInnerSource, SetRelation.EQUAL) {
			@Override
			public ExampleSetMetaData modifyExampleSet(ExampleSetMetaData metaData) throws UndefinedParameterError {
				metaData.getNumberOfExamples().reduceByUnknownAmount();
				return super.modifyExampleSet(metaData);
			}
		});
		getTransformer().addRule(inputExtender.makePassThroughRule());
		getTransformer().addRule(new SubprocessTransformRule(getSubprocess(0)));
		getTransformer().addRule(outputExtender.makePassThroughRule());
	}

	@Override
	public void doWork() throws OperatorException {
		ExampleSet exampleSet = exampleSetInput.getData();

		Attribute clusterAttribute = exampleSet.getAttributes().getCluster();
		if (clusterAttribute == null) {
			throw new UserError(this, 113, Attributes.CLUSTER_NAME);
		}

		SplittedExampleSet splitted = SplittedExampleSet.splitByAttribute(exampleSet, clusterAttribute);
		numberOfClusters = splitted.getNumberOfSubsets();
		for (int i = 0; i < numberOfClusters; i++) {
			splitted.selectSingleSubset(i);

			clearAllInnerSinks();
			subsetInnerSource.deliver(splitted);
			inputExtender.passCloneThrough();
			super.doWork();
			inApplyLoop();
		}

		outputExtender.passDataThrough();
	}
}