/*
 *  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;

import java.util.Iterator;
import java.util.Map;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.AttributeRole;
import com.rapidminer.example.Attributes;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.SimpleAttributes;
import com.rapidminer.example.table.AttributeFactory;
import com.rapidminer.example.table.BinominalMapping;
import com.rapidminer.example.table.NominalMapping;
import com.rapidminer.example.table.PolynominalMapping;
import com.rapidminer.example.table.ViewAttribute;
import com.rapidminer.operator.OperatorException;

/**
 * This model removes all nominal values. During application it might happen
 * that missing values are introduced.
 * If applied on data, new columns are created in a cloned example set.
 * 
 * @author Sebastian Land
 */
public class RemoveUnusedNominalValuesModel extends PreprocessingModel {

    public static class MappingTranslation {
        NominalMapping originalMapping;
        NominalMapping newMapping;

        public MappingTranslation(NominalMapping originalMapping) {
            this.originalMapping = originalMapping;
            if (originalMapping instanceof PolynominalMapping) {
                this.newMapping = new PolynominalMapping();
            } else {
                this.newMapping = new BinominalMapping();
            }
        }
    }

    private static final long serialVersionUID = 1L;
    private Map<String, MappingTranslation> translations;

    protected RemoveUnusedNominalValuesModel(ExampleSet exampleSet, Map<String, MappingTranslation> translations) {
        super(exampleSet);

        this.translations = translations;
    }

    @Override
    public Attributes getTargetAttributes(ExampleSet viewParent) {
        SimpleAttributes attributes = new SimpleAttributes();
        // add special attributes to new attributes
        Iterator<AttributeRole> roleIterator = viewParent.getAttributes().allAttributeRoles();
        while (roleIterator.hasNext()) {
            AttributeRole role = roleIterator.next();
            if (role.isSpecial()) {
                attributes.add(role);
            }
        }
        // add regular attributes
        for (Attribute attribute : viewParent.getAttributes()) {
            MappingTranslation mappingTranslation = translations.get(attribute.getName());
            if (!attribute.isNominal() || mappingTranslation == null) {
                attributes.addRegular(attribute);
            } else {
                // giving new attributes old name: connection to rangesMap
                attributes.addRegular(new ViewAttribute(this, attribute, attribute.getName(), attribute.getValueType(), mappingTranslation.newMapping));
            }
        }
        return attributes;
    }

    @Override
    public double getValue(Attribute targetAttribute, double value) {
        MappingTranslation mappingTranslation = translations.get(targetAttribute.getName());
        if (mappingTranslation != null) {
            String nominalValue = mappingTranslation.originalMapping.mapIndex((int) value);
            int result = mappingTranslation.newMapping.getIndex(nominalValue);
            if (result != -1)
                return result;
            return Double.NaN;
        }
        return Double.NaN;
    }

    @Override
    public ExampleSet applyOnData(ExampleSet exampleSet) throws OperatorException {
        ExampleSet resultSet = (ExampleSet) exampleSet.clone();

        Attributes attributes = exampleSet.getAttributes();
        Iterator<Attribute> iterator = attributes.iterator();
        while (iterator.hasNext()) {
            Attribute currentAttribute = iterator.next();
            MappingTranslation mappingTranslation = translations.get(currentAttribute.getName());
            if (mappingTranslation != null) {
                // removing attribute from resultSet
                Attributes resultAttributes = resultSet.getAttributes();
                resultAttributes.remove(resultAttributes.get(currentAttribute.getName()));

                // construct new attribute and add to memory table and exampleset
                Attribute newAttribute = AttributeFactory.createAttribute(currentAttribute.getName(), currentAttribute.getValueType(), currentAttribute.getBlockType());
                resultSet.getExampleTable().addAttribute(newAttribute);
                resultAttributes.addRegular(newAttribute);
                AttributeRole role = attributes.getRole(currentAttribute);
                if (role.isSpecial())
                    resultAttributes.setSpecialAttribute(newAttribute, role.getSpecialName());

                // now copy value for each example
                Iterator<Example> exampleIterator = exampleSet.iterator();
                for (Example resultExample : resultSet) {
                    Example example = exampleIterator.next();
                    String nominalValue = example.getValueAsString(currentAttribute);
                    int result = mappingTranslation.newMapping.getIndex(nominalValue);
                    if (result != -1)
                        resultExample.setValue(newAttribute, result);
                    else
                        resultExample.setValue(newAttribute, Double.NaN);
                }
                newAttribute.setMapping(mappingTranslation.newMapping);
            }
        }

        return resultSet;
    }
}