/*
    * 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
    *
    *      https://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.
   */
  
  /*
   * This is not the original file distributed by the Apache Software Foundation
   * It has been modified by the Hipparchus project
   */
  package org.hipparchus.geometry.spherical.twod;
  
  import org.hipparchus.geometry.euclidean.threed.Vector3D;
  import org.hipparchus.geometry.partitioning.AbstractSubHyperplane;
  import org.hipparchus.geometry.partitioning.Hyperplane;
  import org.hipparchus.geometry.partitioning.Region;
  import org.hipparchus.geometry.spherical.oned.Arc;
  import org.hipparchus.geometry.spherical.oned.ArcsSet;
  import org.hipparchus.geometry.spherical.oned.Sphere1D;
  import org.hipparchus.util.FastMath;
  
  /** This class represents a sub-hyperplane for {@link Circle}.
   */
  public class SubCircle extends AbstractSubHyperplane<Sphere2D, Sphere1D> {
  
      /** Simple constructor.
       * @param hyperplane underlying hyperplane
       * @param remainingRegion remaining region of the hyperplane
       */
      public SubCircle(final Hyperplane<Sphere2D> hyperplane,
                       final Region<Sphere1D> remainingRegion) {
          super(hyperplane, remainingRegion);
      }
  
      /** {@inheritDoc} */
      @Override
      protected AbstractSubHyperplane<Sphere2D, Sphere1D> buildNew(final Hyperplane<Sphere2D> hyperplane,
                                                                   final Region<Sphere1D> remainingRegion) {
          return new SubCircle(hyperplane, remainingRegion);
      }
  
      /** {@inheritDoc} */
      @Override
      public SplitSubHyperplane<Sphere2D> split(final Hyperplane<Sphere2D> hyperplane) {
  
          final Circle thisCircle   = (Circle) getHyperplane();
          final Circle otherCircle  = (Circle) hyperplane;
          final double angle = Vector3D.angle(thisCircle.getPole(), otherCircle.getPole());
  
          if (angle < thisCircle.getTolerance() || angle > FastMath.PI - thisCircle.getTolerance()) {
              // the two circles are aligned or opposite
              return new SplitSubHyperplane<Sphere2D>(null, null);
          } else {
              // the two circles intersect each other
              final Arc    arc          = thisCircle.getInsideArc(otherCircle);
              final ArcsSet.Split split = ((ArcsSet) getRemainingRegion()).split(arc);
              final ArcsSet plus        = split.getPlus();
              final ArcsSet minus       = split.getMinus();
              return new SplitSubHyperplane<Sphere2D>(plus  == null ? null : new SubCircle(thisCircle.copySelf(), plus),
                                                      minus == null ? null : new SubCircle(thisCircle.copySelf(), minus));
          }
  
      }
  
  }