/*
 * 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
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package org.apache.commons.math.stat.clustering;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

import java.util.Arrays;
import java.util.List;
import java.util.Random;

import org.junit.Test;

public class KMeansPlusPlusClustererTest {

	@Test
	public void dimension2() {
		KMeansPlusPlusClusterer<EuclideanIntegerPoint> transformer = new KMeansPlusPlusClusterer<EuclideanIntegerPoint>(
				new Random(1746432956321l));
		EuclideanIntegerPoint[] points = new EuclideanIntegerPoint[] {

				// first expected cluster
				new EuclideanIntegerPoint(new int[] { -15, 3 }), new EuclideanIntegerPoint(new int[] { -15, 4 }),
				new EuclideanIntegerPoint(new int[] { -15, 5 }), new EuclideanIntegerPoint(new int[] { -14, 3 }),
				new EuclideanIntegerPoint(new int[] { -14, 5 }), new EuclideanIntegerPoint(new int[] { -13, 3 }),
				new EuclideanIntegerPoint(new int[] { -13, 4 }), new EuclideanIntegerPoint(new int[] { -13, 5 }),

				// second expected cluster
				new EuclideanIntegerPoint(new int[] { -1, 0 }), new EuclideanIntegerPoint(new int[] { -1, -1 }),
				new EuclideanIntegerPoint(new int[] { 0, -1 }), new EuclideanIntegerPoint(new int[] { 1, -1 }),
				new EuclideanIntegerPoint(new int[] { 1, -2 }),

				// third expected cluster
				new EuclideanIntegerPoint(new int[] { 13, 3 }), new EuclideanIntegerPoint(new int[] { 13, 4 }),
				new EuclideanIntegerPoint(new int[] { 14, 4 }), new EuclideanIntegerPoint(new int[] { 14, 7 }),
				new EuclideanIntegerPoint(new int[] { 16, 5 }), new EuclideanIntegerPoint(new int[] { 16, 6 }),
				new EuclideanIntegerPoint(new int[] { 17, 4 }), new EuclideanIntegerPoint(new int[] { 17, 7 })

		};
		List<Cluster<EuclideanIntegerPoint>> clusters = transformer.cluster(Arrays.asList(points), 3, 10);

		assertEquals(3, clusters.size());
		boolean cluster1Found = false;
		boolean cluster2Found = false;
		boolean cluster3Found = false;
		for (Cluster<EuclideanIntegerPoint> cluster : clusters) {
			int[] center = cluster.getCenter().getPoint();
			if (center[0] < 0) {
				cluster1Found = true;
				assertEquals(8, cluster.getPoints().size());
				assertEquals(-14, center[0]);
				assertEquals(4, center[1]);
			} else if (center[1] < 0) {
				cluster2Found = true;
				assertEquals(5, cluster.getPoints().size());
				assertEquals(0, center[0]);
				assertEquals(-1, center[1]);
			} else {
				cluster3Found = true;
				assertEquals(8, cluster.getPoints().size());
				assertEquals(15, center[0]);
				assertEquals(5, center[1]);
			}
		}
		assertTrue(cluster1Found);
		assertTrue(cluster2Found);
		assertTrue(cluster3Found);

	}

}
