/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2008 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.learner.associations;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.table.AttributeFactory;
import com.rapidminer.example.table.MemoryExampleTable;
import com.rapidminer.operator.IOObject;
import com.rapidminer.operator.MissingIOObjectException;
import com.rapidminer.operator.Operator;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.tools.Ontology;

/**
 * This operator takes all FrequentItemSet sets within IOObjects and
 * creates attributes for every frequent item set. This attributes indicate
 * if the examples contains all values of this frequent item set. The attributes
 * will contain values 0 or 1 and are numerical.
 * 
 * @author Sebastian Land
 * @version $Id: FrequentItemSetAttributeCreator.java,v 1.5 2008/07/07 07:06:46 ingomierswa Exp $
 */
public class FrequentItemSetAttributeCreator extends Operator {

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

	public IOObject[] apply() throws OperatorException {
		ExampleSet exampleSet = getInput(ExampleSet.class);

		try {
			while (true) {
				FrequentItemSets sets = getInput(FrequentItemSets.class);
				// mapping from name to attribute
				HashMap<String, Attribute> attributeMap = new HashMap<String, Attribute>();
				for (Attribute attribute: exampleSet.getAttributes()) {
					attributeMap.put(attribute.getName(), attribute);
				}
				
				// mapping from frequent set to new attribute
				HashMap<FrequentItemSet, Attribute> setAttributeMap = new HashMap<FrequentItemSet, Attribute>();
				Collection<Attribute> newAttributes = new ArrayList<Attribute>(sets.size());
				for (FrequentItemSet set: sets) {
					// adding attribute
					Attribute newAttribute = AttributeFactory.createAttribute(set.toString(), Ontology.NUMERICAL);
					newAttributes.add(newAttribute);
					setAttributeMap.put(set, newAttribute);
					exampleSet.getAttributes().addRegular(newAttribute);
				}
				MemoryExampleTable table = (MemoryExampleTable) exampleSet.getExampleTable();
				table.addAttributes(newAttributes);
				
				// running over examples 
				for (Example example: exampleSet) {
					// running over every frequent Set
					for (FrequentItemSet set: sets) {
						example.setValue(setAttributeMap.get(set), checkConditions(example, set, attributeMap));
					}
				}
			}
		} catch (MissingIOObjectException e) {}
		return new IOObject[] {exampleSet};
	}

	private double checkConditions(Example example, FrequentItemSet set, HashMap<String, Attribute> attributeMap) {
		boolean matches = true;
		for (Item item: set.getItems()) {
			Attribute conditionAttribute = attributeMap.get(item.toString());
			if (conditionAttribute != null) {
				double conditionValue = conditionAttribute.getMapping().mapString("true");
				matches = matches && example.getValue(conditionAttribute) == conditionValue;
			} else {
				matches = false;
			}
		}
		if (matches)
			return 1d;
		return 0d;
	}

	public Class<?>[] getInputClasses() {
		return new Class[] {ExampleSet.class, FrequentItemSets.class};
	}

	public Class<?>[] getOutputClasses() {
		return new Class[] {ExampleSet.class};
	}

}