/*
 *  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 java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.AttributeRole;
import com.rapidminer.example.Attributes;
import com.rapidminer.example.ExampleSet;
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.CollectingPortPairExtender;
import com.rapidminer.operator.ports.InputPort;
import com.rapidminer.operator.ports.OutputPort;
import com.rapidminer.operator.ports.metadata.AttributeMetaData;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.ports.metadata.ExampleSetPassThroughRule;
import com.rapidminer.operator.ports.metadata.SetRelation;
import com.rapidminer.operator.ports.metadata.SubprocessTransformRule;
import com.rapidminer.parameter.UndefinedParameterError;


/**
 * Performs the inner operator for all label attributes, i.e. special attributes
 * whose role name starts with "label". In each iteration one of the
 * multiple labels is used as label. The results of the inner operators are
 * collected and returned. The example set will be consumed during the
 * iteration.
 * 
 * @author Ingo Mierswa
 */
public class MultipleLabelIterator extends OperatorChain {

	private final InputPort exampleSetInput = getInputPorts().createPort("example set");
	private final OutputPort exampleInnerSource = getSubprocess(0).getInnerSources().createPort("example set");
	CollectingPortPairExtender outExtender = new CollectingPortPairExtender("out", getSubprocess(0).getInnerSinks(), getOutputPorts());

	public MultipleLabelIterator(OperatorDescription description) {
		super(description, "Iteration");
		outExtender.start();
		getTransformer().addRule(new ExampleSetPassThroughRule(exampleSetInput, exampleInnerSource, SetRelation.EQUAL) {
			@Override
			public ExampleSetMetaData modifyExampleSet(ExampleSetMetaData metaData) throws UndefinedParameterError {
				AttributeMetaData myLabel = metaData.getLabelMetaData();
				if (myLabel != null)
					metaData.removeAttribute(myLabel);
				for (AttributeMetaData amd : metaData.getAllAttributes()) {
					if (amd.getName().startsWith(Attributes.LABEL_NAME)) { 
						amd.setRole(Attributes.LABEL_NAME);
						break;
					}
				}					
				return metaData;
			}
		});
		getTransformer().addRule(new SubprocessTransformRule(getSubprocess(0)));
		getTransformer().addRule(outExtender.makePassThroughRule());
	}

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

		Attribute[] labels = getLabels(exampleSet);
		if (labels.length == 0) {
			throw new UserError(this, 105);
		}

		outExtender.reset();
		for (int i = 0; i < labels.length; i++) {
			ExampleSet cloneSet = (ExampleSet) exampleSet.clone();
			cloneSet.getAttributes().setLabel(labels[i]);
			exampleInnerSource.deliver(cloneSet);

			getSubprocess(0).execute();
			outExtender.collect();            
			inApplyLoop();
		}
	}

	private Attribute[] getLabels(ExampleSet exampleSet) {
		List<Attribute> attributes = new LinkedList<Attribute>();
		Iterator<AttributeRole> i = exampleSet.getAttributes().specialAttributes();
		while (i.hasNext()) {
			AttributeRole role = i.next();
			String name = role.getSpecialName();
			if (name.startsWith(Attributes.LABEL_NAME)) {
				attributes.add(role.getAttribute());
			}
		}
		Attribute[] result = new Attribute[attributes.size()];
		attributes.toArray(result);
		return result;
	}
}