/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.math.ode.sampling;

import org.apache.commons.math.ode.DerivativeException;
import org.apache.commons.math.ode.FirstOrderIntegrator;
import org.apache.commons.math.ode.IntegratorException;
import org.apache.commons.math.ode.TestProblem3;
import org.apache.commons.math.ode.nonstiff.DormandPrince54Integrator;
import org.apache.commons.math.ode.sampling.FixedStepHandler;
import org.apache.commons.math.ode.sampling.StepNormalizer;

import junit.framework.*;

public class StepNormalizerTest extends TestCase {

	public StepNormalizerTest(String name) {
		super(name);
		pb = null;
		integ = null;
	}

	public void testBoundaries() throws DerivativeException, IntegratorException {
		double range = pb.getFinalTime() - pb.getInitialTime();
		setLastSeen(false);
		integ.addStepHandler(new StepNormalizer(range / 10.0, new FixedStepHandler() {
			private static final long serialVersionUID = 1650337364641626444L;
			private boolean firstCall = true;

			public void handleStep(double t, double[] y, double[] yDot, boolean isLast) {
				if (firstCall) {
					checkValue(t, pb.getInitialTime());
					firstCall = false;
				}
				if (isLast) {
					setLastSeen(true);
					checkValue(t, pb.getFinalTime());
				}
			}
		}));
		integ.integrate(pb, pb.getInitialTime(), pb.getInitialState(), pb.getFinalTime(),
				new double[pb.getDimension()]);
		assertTrue(lastSeen);
	}

	public void testBeforeEnd() throws DerivativeException, IntegratorException {
		final double range = pb.getFinalTime() - pb.getInitialTime();
		setLastSeen(false);
		integ.addStepHandler(new StepNormalizer(range / 10.5, new FixedStepHandler() {
			private static final long serialVersionUID = 2228457391561277298L;

			public void handleStep(double t, double[] y, double[] yDot, boolean isLast) {
				if (isLast) {
					setLastSeen(true);
					checkValue(t, pb.getFinalTime() - range / 21.0);
				}
			}
		}));
		integ.integrate(pb, pb.getInitialTime(), pb.getInitialState(), pb.getFinalTime(),
				new double[pb.getDimension()]);
		assertTrue(lastSeen);
	}

	public void checkValue(double value, double reference) {
		assertTrue(Math.abs(value - reference) < 1.0e-10);
	}

	public void setLastSeen(boolean lastSeen) {
		this.lastSeen = lastSeen;
	}

	public static Test suite() {
		return new TestSuite(StepNormalizerTest.class);
	}

	@Override
	public void setUp() {
		pb = new TestProblem3(0.9);
		double minStep = 0;
		double maxStep = pb.getFinalTime() - pb.getInitialTime();
		integ = new DormandPrince54Integrator(minStep, maxStep, 10.e-8, 1.0e-8);
		lastSeen = false;
	}

	@Override
	public void tearDown() {
		pb = null;
		integ = null;
	}

	TestProblem3 pb;
	FirstOrderIntegrator integ;
	boolean lastSeen;

}
