/*
    * 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.geometry.hull;
  
  import java.util.Arrays;
  import java.util.List;
  
  import org.apache.commons.geometry.core.precision.DoublePrecisionContext;
  import org.apache.commons.geometry.core.precision.EpsilonDoublePrecisionContext;
  import org.apache.commons.geometry.euclidean.EuclideanTestUtils;
  import org.apache.commons.geometry.euclidean.twod.ConvexArea;
  import org.apache.commons.geometry.euclidean.twod.Vector2D;
  import org.apache.commons.geometry.hull.euclidean.twod.ConvexHull2D;
  import org.apache.commons.geometry.hull.euclidean.twod.MonotoneChain;
  import org.junit.Assert;
  import org.junit.Test;
  
  /** This class contains code listed as examples in the user guide and other documentation.
   * If any portion of this code changes, the corresponding examples in the documentation <em>must</em> be updated.
   */
  public class DocumentationExamplesTest {
  
      private static final double TEST_EPS = 1e-15;
  
      @Test
      public void testMonotoneChainExample() {
          final DoublePrecisionContext precision = new EpsilonDoublePrecisionContext(1e-10);
  
          // create a list of input points for the algorithm
          final List<Vector2D> pts = Arrays.asList(
                      Vector2D.ZERO,
                      Vector2D.of(0.5, 0.5),
                      Vector2D.of(0, 0.5),
                      Vector2D.of(0, 1),
                      Vector2D.of(0.25, 0.1),
                      Vector2D.of(1, 0),
                      Vector2D.of(1, 1),
                      Vector2D.of(0.75, 0.9)
                  );
  
          // create an instance of the monotone chain convex hull generator
          final MonotoneChain mc = new MonotoneChain(precision);
  
          // compute the convex hull
          final ConvexHull2D hull = mc.generate(pts);
  
          // list the vertices from the input that were used in the hull
          final List<Vector2D> vertices = hull.getVertices(); // [(0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0)]
  
          // get the hull as a region
          final ConvexArea region = hull.getRegion();
          final boolean containsAll = pts.stream().allMatch(region::contains); // true - region contains all input points
  
          // ---
          Assert.assertEquals(4, vertices.size());
          EuclideanTestUtils.assertCoordinatesEqual(Vector2D.ZERO, vertices.get(0), TEST_EPS);
          EuclideanTestUtils.assertCoordinatesEqual(Vector2D.of(1, 0), vertices.get(1), TEST_EPS);
          EuclideanTestUtils.assertCoordinatesEqual(Vector2D.of(1, 1), vertices.get(2), TEST_EPS);
          EuclideanTestUtils.assertCoordinatesEqual(Vector2D.of(0, 1), vertices.get(3), TEST_EPS);
  
          Assert.assertTrue(containsAll);
      }
  }