/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2014 by RapidMiner and the contributors
 *
 *  Complete list of developers available at our web site:
 *
 *       http://rapidminer.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.Operator;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.ports.InputPort;
import com.rapidminer.operator.ports.OutputPort;
import com.rapidminer.operator.ports.metadata.ExampleSetPassThroughRule;
import com.rapidminer.operator.ports.metadata.SetRelation;
import com.rapidminer.tools.Ontology;

/**
 * This operator takes a FrequentItemSet set within IOObjects and
 * creates attributes for every frequent item set. This attributes indicate
 * if the examples contains all items of this set. The attributes
 * will contain values 0 or 1 and are numerical.
 * 
 * @author Sebastian Land
 */
public class FrequentItemSetAttributeCreator extends Operator {

	private InputPort exampleSetInput = getInputPorts().createPort("example set", ExampleSet.class);
	private InputPort frequentItemSetsInput = getInputPorts().createPort("frequent item sets", FrequentItemSets.class);
	
	private OutputPort exampleSetOutput = getOutputPorts().createPort("example set");
	
	public FrequentItemSetAttributeCreator(OperatorDescription description) {
		super(description);
		
		getTransformer().addRule(new ExampleSetPassThroughRule(exampleSetInput, exampleSetOutput, SetRelation.SUPERSET));
	}

	@Override
	public void doWork() throws OperatorException {
		ExampleSet exampleSet = exampleSetInput.getData(ExampleSet.class);
		FrequentItemSets sets = frequentItemSetsInput.getData(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));
			}
		}
		exampleSetOutput.deliver(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;
	}
}