/*
 *  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;

import java.util.Iterator;
import java.util.List;

import com.rapidminer.example.ExampleSet;
import com.rapidminer.operator.ports.InputPort;
import com.rapidminer.operator.ports.OutputPort;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.ports.metadata.ModelApplicationRule;
import com.rapidminer.operator.ports.metadata.ModelMetaData;
import com.rapidminer.operator.ports.metadata.PassThroughRule;
import com.rapidminer.operator.ports.metadata.SimplePrecondition;
import com.rapidminer.operator.preprocessing.PreprocessingOperator;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeBoolean;
import com.rapidminer.parameter.ParameterTypeList;
import com.rapidminer.parameter.ParameterTypeString;

/**
 * This operator applies a {@link Model} to an {@link ExampleSet}. All
 * parameters of the training process should be stored within the model.
 * However, this operator is able to take any parameters for the rare case that
 * the particular model evaluates parameters during application. Models can be read from
 * a file by using a {@link com.rapidminer.operator.io.ModelLoader}.
 * 
 * @author Ingo Mierswa, Simon Fischer
 */
public class ModelApplier extends Operator {

	/** The parameter name for "value" */
	public static final String PARAMETER_KEY = "key";

	/** The possible parameters used by the model during application time. */
	public static final String PARAMETER_APPLICATION_PARAMETERS = "application_parameters";

	/** Indicates if preprocessing models should create a view instead of changing the data. */
	private static final String PARAMETER_CREATE_VIEW = "create_view";

	private final InputPort modelInput = getInputPorts().createPort("model");
	private final InputPort exampleSetInput = getInputPorts().createPort("unlabelled data");
	private final OutputPort exampleSetOutput = getOutputPorts().createPort("labelled data");
	private final OutputPort modelOutput = getOutputPorts().createPort("model");

	public ModelApplier(OperatorDescription description) {
		super(description);
		modelInput.addPrecondition(new SimplePrecondition(modelInput, new ModelMetaData(Model.class, new ExampleSetMetaData())));
		exampleSetInput.addPrecondition(new SimplePrecondition(exampleSetInput, new ExampleSetMetaData()));
		getTransformer().addRule(new ModelApplicationRule(exampleSetInput, exampleSetOutput, modelInput, false));	
		getTransformer().addRule(new PassThroughRule(modelInput, modelOutput, false));
	}

	/**
	 * Applies the operator and labels the {@link ExampleSet}. The example set
	 * in the input is not consumed.
	 */
	@Override
	public void doWork() throws OperatorException {
		ExampleSet inputExampleSet = exampleSetInput.getData(ExampleSet.class);
		Model model = modelInput.getData(Model.class);

		log("Set parameters for " + model.getClass().getName());
		List<String[]> modelParameters = getParameterList(PARAMETER_APPLICATION_PARAMETERS);
		Iterator<String[]> i = modelParameters.iterator();
		while (i.hasNext()) {
			String[] parameter = i.next();
			model.setParameter(parameter[0], parameter[1]);
		}

		// handling PreprocessingModels: extra treatment for views
		if (getParameterAsBoolean(PARAMETER_CREATE_VIEW)) {
			model.setParameter(PreprocessingOperator.PARAMETER_CREATE_VIEW, true);
		}

		log("Applying " + model.getClass().getName());
		ExampleSet result = inputExampleSet;
		try {
			result = model.apply(inputExampleSet);
		} catch (UserError e) {
			if (e.getOperator() == null)
				e.setOperator(this);
			throw e;
		}

		exampleSetOutput.deliver(result);
		modelOutput.deliver(model);
	}

	@Override
	public boolean shouldAutoConnect(OutputPort port) {
		if (port == modelOutput) {
			return getParameterAsBoolean("keep_model");
		} else {
			return super.shouldAutoConnect(port);
		}
	}

	@Override
	public List<ParameterType> getParameterTypes() {
		List<ParameterType> types = super.getParameterTypes();
		types.add(new ParameterTypeList(PARAMETER_APPLICATION_PARAMETERS, "Model parameters for application (usually not needed).", 
				new ParameterTypeString("key", "The model parameter key."),
				new ParameterTypeString(PARAMETER_KEY, "This key's value")));
		types.add(new ParameterTypeBoolean(PARAMETER_CREATE_VIEW, "Indicates that models should create a new view on the data where possible. Then, instead of changing the data itself, the results are calculated on the fly if needed.", false));
		return types;
	}
}