/*
 *  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.normalization;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Attributes;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.table.AttributeFactory;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.preprocessing.PreprocessingModel;
import com.rapidminer.tools.Ontology;

/**
 * @author Sebastian Land
 *
 */
public abstract class AbstractNormalizationModel extends PreprocessingModel {

	private static final long serialVersionUID = 9003091723155805502L;

	protected AbstractNormalizationModel(ExampleSet exampleSet) {
		super(exampleSet);

	}
	@Override
	public ExampleSet applyOnData(ExampleSet exampleSet) throws OperatorException {
		Attributes attributes = exampleSet.getAttributes();

		// constructing new attributes with generic names, holding old ones, if old type wasn't real
		Attribute[] oldAttributes = new Attribute[attributes.size()];
		int i = 0;
		for (Attribute attribute: attributes) {
			oldAttributes[i] = attribute;
			i++;
		}
		Attribute[] newAttributes = new Attribute[attributes.size()];
		for (i = 0; i < newAttributes.length; i++) {
			newAttributes[i] = oldAttributes[i];
			if (oldAttributes[i].isNumerical())
				if (! Ontology.ATTRIBUTE_VALUE_TYPE.isA(oldAttributes[i].getValueType(), Ontology.REAL)) {
					newAttributes[i] = AttributeFactory.createAttribute(Ontology.REAL);
					exampleSet.getExampleTable().addAttribute(newAttributes[i]);
					attributes.addRegular(newAttributes[i]);
				}
		}

		// applying on data
		applyOnData(exampleSet, oldAttributes, newAttributes);


		// removing old attributes and change new attributes name to old ones if needed
		for (i = 0; i < oldAttributes.length; i++) {
			attributes.remove(oldAttributes[i]);
			// if attribute is new, then remove for later storing in correct order
			if (oldAttributes[i] != newAttributes[i])
				attributes.remove(newAttributes[i]);
			attributes.addRegular(newAttributes[i]);
			newAttributes[i].setName(oldAttributes[i].getName());
		}

		return exampleSet;
	}

	/**
	 * This method must be implemented by the subclasses. Subclasses have to iterate over the exampleset and
	 * on each example iterate over the oldAttribute array and set the new values on the corresponding new attribute
	 */
	protected void applyOnData(ExampleSet exampleSet, Attribute[] oldAttributes, Attribute[] newAttributes) {
		// copying data
		for (Example example: exampleSet) {
			for (int i = 0; i < oldAttributes.length; i++) {
				if (oldAttributes[i].isNumerical())
					example.setValue(newAttributes[i], computeValue(oldAttributes[i], example.getValue(oldAttributes[i])));
			}
		}
	}

	/**
	 * Subclasses might implement this methods in order to return a value if the implementation differs
	 * from the getValue() method for view creation. Otherwise this method just calls getValue(). If this method
	 * does not deliver enough informations, the subclass might override {@link #applyOnData(ExampleSet, Attribute[], Attribute[])}
	 */
	public double computeValue(Attribute attribute, double oldValue) {
		return getValue(attribute, oldValue);
	}


}