/*
 *  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.preprocessing.filter;

import java.util.Collection;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;

import com.rapidminer.example.ExampleSet;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.annotation.ResourceConsumptionEstimator;
import com.rapidminer.operator.ports.metadata.AttributeMetaData;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.ports.metadata.SetRelation;
import com.rapidminer.operator.preprocessing.PreprocessingModel;
import com.rapidminer.operator.preprocessing.PreprocessingOperator;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeBoolean;
import com.rapidminer.tools.Ontology;
import com.rapidminer.tools.OperatorResourceConsumptionHandler;

/**
 * This operator maps the values of all nominal values to binary attributes. For example,
 * if a nominal attribute with name "costs" and possible nominal values
 * "low", "moderate", and "high" is transformed, the result
 * is a set of three binominal attributes "costs = low", "costs = moderate",
 * and "costs = high". Only one of the values of each attribute is true for a specific
 * example, the other values are false. 
 *
 * @author Sebastian Land, Ingo Mierswa
 */
public class NominalToBinominal extends PreprocessingOperator {

	public static final String PARAMETER_USE_UNDERSCORE_IN_NAME = "use_underscore_in_name";

	public static final String PARAMETER_TRANSFORM_BINOIMINAL = "transform_binominal";

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

	@Override
	protected Collection<AttributeMetaData> modifyAttributeMetaData(ExampleSetMetaData emd, AttributeMetaData amd) {
		boolean transformBinominal = getParameterAsBoolean(PARAMETER_TRANSFORM_BINOIMINAL);
		if (amd.isNominal()) {
			Collection<AttributeMetaData> newAttributeMetaDataCollection = new LinkedList<AttributeMetaData>();
			if (!transformBinominal && (amd.getValueSet().size() == 2)) {
				amd.setType(Ontology.BINOMINAL);
				return Collections.singletonList(amd);
			} else {
				if (amd.getValueSetRelation() != SetRelation.UNKNOWN) {
					for (String value : amd.getValueSet()) {
						String name = amd.getName() + 
						(getParameterAsBoolean(PARAMETER_USE_UNDERSCORE_IN_NAME) ? "_" : " = ") +
						value;
						AttributeMetaData newAttributeMetaData = new AttributeMetaData(name, Ontology.BINOMINAL);
						Set<String> values = new TreeSet<String>();
						values.add("false");
						values.add("true");
						newAttributeMetaData.setValueSet(values, SetRelation.EQUAL);
						newAttributeMetaDataCollection.add(newAttributeMetaData);
						emd.mergeSetRelation(amd.getValueSetRelation());
					}
				}
				return newAttributeMetaDataCollection;
			}
		} else {
			return null; //Collections.singleton(amd);
		}		
	}


	@Override
	public PreprocessingModel createPreprocessingModel(ExampleSet exampleSet) throws OperatorException {
		PreprocessingModel model = new NominalToBinominalModel(exampleSet, getParameterAsBoolean(PARAMETER_TRANSFORM_BINOIMINAL), getParameterAsBoolean(PARAMETER_USE_UNDERSCORE_IN_NAME));
		return model;
	}

	@Override
	public Class<? extends PreprocessingModel> getPreprocessingModelClass() {
		return NominalToBinominalModel.class;
	}
	
	@Override
	public List<ParameterType> getParameterTypes() {
		List<ParameterType> types = super.getParameterTypes();
		types.add(new ParameterTypeBoolean(PARAMETER_TRANSFORM_BINOIMINAL, "Indicates if attributes which are already binominal should be dichotomized.", false, false));
		types.add(new ParameterTypeBoolean(PARAMETER_USE_UNDERSCORE_IN_NAME, "Indicates if underscores should be used in the new attribute names instead of empty spaces and '='. Although the resulting names are harder to read for humans it might be more appropriate to use these if the data should be written into a database system.", false));
		return types;
	}

	@Override
	protected int[] getFilterValueTypes() {
		return new int[] { Ontology.NOMINAL };
	}
	
	@Override
	public ResourceConsumptionEstimator getResourceConsumptionEstimator() {
		return OperatorResourceConsumptionHandler.getResourceConsumptionEstimator(getInputPort(), NominalToBinominal.class, attributeSelector);
	}

}