/*
 *  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.gui.renderer.itemsets;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import com.rapidminer.gui.graphs.AssociationRulesGraphCreator;
import com.rapidminer.gui.graphs.GraphCreator;
import com.rapidminer.gui.renderer.AbstractGraphRenderer;
import com.rapidminer.operator.IOContainer;
import com.rapidminer.operator.learner.associations.AssociationRule;
import com.rapidminer.operator.learner.associations.AssociationRules;

/**
 * A renderer for the graph view of association rules.
 * 
 * @author Ingo Mierswa, Nils Woehler
 */
public class AssociationRulesGraphRenderer extends AbstractGraphRenderer {

	private final int MAX_RULE_NUMBER = 500;

	@Override
	public GraphCreator<String, String> getGraphCreator(Object renderable, IOContainer ioContainer) {
		AssociationRules rules = (AssociationRules) renderable;
		int numberOfRules = rules.getNumberOfRules();
		if (numberOfRules > 0) {
			if (numberOfRules > MAX_RULE_NUMBER ) {
				List<AssociationRule> ruleList = new ArrayList<AssociationRule>(numberOfRules);
				for(int i = 0; i < numberOfRules; ++i) {
					ruleList.add(rules.getRule(i));
				}
				Collections.sort(ruleList, new Comparator<AssociationRule>() {

					@Override
					public int compare(AssociationRule rule1, AssociationRule rule2) {
						if(rule1.getConfidence() == rule2.getConfidence()) {
							return 0;
						} else if(rule1.getConfidence() < rule2.getConfidence()) {
							return -1;
						} else {
							return 1;
						}
					}
				});
				AssociationRules filteredRules = new AssociationRules();
				for(int i = 0; i < MAX_RULE_NUMBER; ++i) {
					filteredRules.addItemRule(ruleList.get(i));
				}
				rules = filteredRules;
			}
			return new AssociationRulesGraphCreator(rules);

		} else {
			return null;
		}
	}
}