/*
 *  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.visualization;

import com.rapidminer.operator.Model;
import com.rapidminer.operator.Operator;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.ResultObjectAdapter;
import com.rapidminer.operator.learner.FormulaProvider;
import com.rapidminer.operator.ports.InputPort;
import com.rapidminer.operator.ports.OutputPort;
import com.rapidminer.operator.ports.metadata.GenerateNewMDRule;

/**
 * This operator extracts a prediction calculation formula from the given model 
 * and stores the formula in a formula result object which can then be written
 * to a file, e.g. with the ResultWriter operator.
 * 
 * Please note that not all RapidMiner models provide a formula.
 * 
 * @author Ingo Mierswa
 */
public class FormulaExtractor extends Operator {

	private static class FormulaResult extends ResultObjectAdapter {

		private static final long serialVersionUID = 4106026192882970425L;
		
		private String formula;
		
		public FormulaResult(String formula) {
			this.formula = formula;
		}
		
		@Override
		public String getName() {
			return "Formula";
		}
		
		@Override
		public String toString() {
			return formula;
		}
	}
	
	private InputPort modelInput = getInputPorts().createPort("model", Model.class);
	private OutputPort formulaOutput = getOutputPorts().createPort("formula");
	private OutputPort modelOutput = getOutputPorts().createPort("model");
	
	public FormulaExtractor(OperatorDescription description) {
		super(description);
		getTransformer().addPassThroughRule(modelInput, modelOutput);
		getTransformer().addRule(new GenerateNewMDRule(formulaOutput, FormulaResult.class));
	}

	@Override
	public void doWork() throws OperatorException {
		Model model = modelInput.getData();
		
		if (model instanceof FormulaProvider) {
			formulaOutput.deliver(new FormulaResult(((FormulaProvider)model).getFormula()));			
		} else {
			logWarning("The model is not capable of producing formulas, formula will be empty...");
			formulaOutput.deliver(new FormulaResult("Model is not capable of producing formulas."));
		}
		modelOutput.deliver(model);
	}
}