package org.djutils.draw.line;
   
   import java.util.ArrayList;
   import java.util.Arrays;
   import java.util.Iterator;
   import java.util.List;
   
   import org.djutils.draw.InvalidProjectionException;
   import org.djutils.draw.point.Point3d;
  import org.djutils.exceptions.Throw;
  
  /**
   * Closed PolyLine3d. The actual closing point (which is the same as the starting point) is NOT included in the super
   * PolyLine3d. The constructors automatically remove the last point if it is a at the same location as the first point.
   * <p>
   * Copyright (c) 2020-2025 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="https://djutils.org/docs/current/djutils/licenses.html">DJUTILS License</a>.
   * </p>
   * @author <a href="https://www.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   * @author <a href="https://github.com/peter-knoppers">Peter Knoppers</a>
   * @author <a href="https://github.com/wjschakel">Wouter Schakel</a>
   */
  public class Polygon3d extends PolyLine3d
  {
      /**
       * Construct a new Polygon3d.
       * @param x the x coordinates of the points
       * @param y the y coordinates of the points
       * @param z the z coordinates of the points
       * @throws IllegalArgumentException when any two successive points are equal, or when there are too few points
       */
      public Polygon3d(final double[] x, final double[] y, final double[] z)
      {
          this(NO_FILTER, x, y, z);
      }
  
      /**
       * Construct a new Polygon3d.
       * @param epsilon minimum distance between points to be considered different (these will <b>not</b> be filtered out)
       * @param x the x coordinates of the points
       * @param y the y coordinates of the points
       * @param z the z coordinates of the points
       * @throws IllegalArgumentException when any two successive points are equal, or when there are too few points
       */
      public Polygon3d(final double epsilon, final double[] x, final double[] y, final double[] z)
      {
          super(epsilon, fixClosingPoint(Throw.whenNull(x, "x"), Throw.whenNull(y, "y"), Throw.whenNull(z, "z")),
                  fixClosingPoint(y, x, z), fixClosingPoint(z, x, y));
      }
  
      /**
       * Ensure that the last elements in three arrays are is not equal to the first. Remove the last element if necessary.
       * @param a the a array
       * @param b the b array
       * @param c the c array
       * @return the <code>a</code> array (possibly a copy with the last element removed)
       */
      static double[] fixClosingPoint(final double[] a, final double[] b, final double[] c)
      {
          if (a.length > 1 && b.length == a.length && c.length == a.length && a[0] == a[a.length - 1] && b[0] == b[a.length - 1]
                  && c[0] == c[c.length - 1])
          {
              return Arrays.copyOf(a, a.length - 1);
          }
          return a;
      }
  
      /**
       * Construct a new Polygon3d.
       * @param points array of Point3d objects.
       * @throws NullPointerException when <code>points</code> is <code>null</code>
       * @throws IllegalArgumentException when <code>points</code> is too short, or contains successive duplicate points
       */
      public Polygon3d(final Point3d[] points)
      {
          this(NO_FILTER, points);
      }
  
      /**
       * Construct a new Polygon3d.
       * @param epsilon minimum distance between points to be considered different (these will <b>not</b> be filtered out)
       * @param points array of Point3d objects.
       * @throws NullPointerException when <code>points</code> is <code>null</code>
       * @throws IllegalArgumentException when <code>points</code> is too short, or contains successive duplicate points
       */
      public Polygon3d(final double epsilon, final Point3d[] points)
      {
          this(epsilon, PolyLine3d.makeArray(Throw.whenNull(points, "points"), p -> p.x), PolyLine3d.makeArray(points, p -> p.y),
                  PolyLine3d.makeArray(points, p -> p.z));
      }
  
      /**
       * Construct a new Polygon3d.
       * @param point1 the first point of the new Polygon3d
       * @param point2 the second point of the new Polygon3d
       * @param otherPoints all remaining points of the new Polygon3d (may be null)
       * @throws NullPointerException when <code>point1</code> or <code>point2</code> is <code>null</code>, or contains a
       *             <code>null</code> value
       * @throws IllegalArgumentException when <code>point1</code> is equal to the last point of <code>otherPoints</code>, or any
      *             two successive points are equal
      */
     public Polygon3d(final Point3d point1, final Point3d point2, final Point3d... otherPoints)
     {
         this(NO_FILTER, point1, point2, otherPoints);
     }
 
     /**
      * Construct a new Polygon3d.
      * @param epsilon minimum distance between points to be considered different (these will <b>not</b> be filtered out)
      * @param point1 the first point of the new Polygon3d
      * @param point2 the second point of the new Polygon3d
      * @param otherPoints all remaining points of the new Polygon3d (may be null)
      * @throws NullPointerException when <code>point1</code> or <code>point2</code> is <code>null</code>, or contains a
      *             <code>null</code> value
      * @throws IllegalArgumentException when <code>point1</code> is equal to the last point of <code>otherPoints</code>, or any
      *             two successive points are equal
      */
     public Polygon3d(final double epsilon, final Point3d point1, final Point3d point2, final Point3d... otherPoints)
     {
         super(epsilon, Throw.whenNull(point1, "point1"), Throw.whenNull(point2, "point2"),
                 fixClosingPoint(point1, otherPoints));
     }
 
     /**
      * Ensure that the last point of otherPoints is not equal to point1. Remove the last point if necessary.
      * @param point1 the first point of a new Polygon3d
      * @param otherPoints the remaining points of a new Polygon3d (may be null)
      * @return <code>otherPoints</code> (possibly a copy thereof with the last entry removed)
      */
     private static Point3d[] fixClosingPoint(final Point3d point1, final Point3d[] otherPoints)
     {
         if (otherPoints == null || otherPoints.length == 0)
         {
             return otherPoints;
         }
         Point3d[] result = otherPoints;
         Point3d lastPoint = result[result.length - 1];
         if (point1.x == lastPoint.x && point1.y == lastPoint.y)
         {
             result = Arrays.copyOf(otherPoints, result.length - 1);
             lastPoint = result[result.length - 1];
         }
         Throw.when(point1.x == lastPoint.x && point1.y == lastPoint.y, IllegalArgumentException.class,
                 "Before last point and last point are at same location");
         return result;
     }
 
     /**
      * Construct a new Polygon3d from a list of Point3d objects.
      * @param points the list of points
      * @throws NullPointerException when <code>points</code> is <code>null</code>
      * @throws IllegalArgumentException when <code>points</code> is too short, or the last two points are at the same location
      */
     public Polygon3d(final List<Point3d> points)
     {
         this(NO_FILTER, points);
     }
 
     /**
      * Construct a new Polygon3d from a list of Point3d objects.
      * @param epsilon minimum distance between points to be considered different (these will <b>not</b> be filtered out)
      * @param points the list of points
      * @throws NullPointerException when <code>points</code> is <code>null</code>
      * @throws IllegalArgumentException when <code>points</code> is too short, or the last two points are at the same location
      */
     public Polygon3d(final double epsilon, final List<Point3d> points)
     {
         super(epsilon, fixClosingPoint(true, Throw.whenNull(points, "points")));
     }
 
     /**
      * Ensure that the last point in the list is different from the first point by possibly removing the last point.
      * @param doNotModifyList if<code>true</code>; the list of points will not be modified (if the last point is to be removed;
      *            the entire list up to the last point is duplicated)
      * @param points the list of points
      * @return the fixed list
      * @throws NullPointerException when <code>points</code> is <code>null</code>
      * @throws IllegalArgumentException when the (resulting) list is too short, or the before last and last point of points have
      *             the same coordinates
      */
     private static List<Point3d> fixClosingPoint(final boolean doNotModifyList, final List<Point3d> points)
     {
         Throw.when(points.size() < 2, IllegalArgumentException.class, "Need at least two points");
         Point3d firstPoint = points.get(0);
         Point3d lastPoint = points.get(points.size() - 1);
         List<Point3d> result = points;
         if (firstPoint.x == lastPoint.x && firstPoint.y == lastPoint.y && firstPoint.z == lastPoint.z)
         {
             if (doNotModifyList)
             {
                 result = new ArrayList<>(points.size() - 1);
                 for (int i = 0; i < points.size() - 1; i++)
                 {
                     result.add(points.get(i));
                 }
             }
             else
             {
                 result.remove(points.size() - 1);
             }
             lastPoint = result.get(result.size() - 1);
         }
         Throw.when(firstPoint.x == lastPoint.x && firstPoint.y == lastPoint.y && firstPoint.z == lastPoint.z,
                 IllegalArgumentException.class, "Before last point and last point are at same location");
         return result;
     }
 
     /**
      * Construct a new Polygon3d from an iterator that yields Point3d.
      * @param iterator the iterator
      */
     public Polygon3d(final Iterator<Point3d> iterator)
     {
         this(NO_FILTER, iterator);
     }
 
     /**
      * Construct a new Polygon3d from an iterator that yields Point3d.
      * @param epsilon minimum distance between points to be considered different (these will <b>not</b> be filtered out)
      * @param iterator the iterator
      */
     public Polygon3d(final double epsilon, final Iterator<Point3d> iterator)
     {
         this(epsilon, fixClosingPoint(false, iteratorToList(Throw.whenNull(iterator, "iterator"))));
     }
 
     /**
      * Construct a new Polygon3d from an existing one. This constructor is primarily intended for use in extending classes.
      * @param polygon the existing Polygon3d
      * @throws NullPointerException when <code>polygon</code> is <code>null</code>
      */
     public Polygon3d(final Polygon3d polygon)
     {
         super(polygon);
     }
 
     @Override
     public double getLength()
     {
         // Length a polygon is computed by taking the length of the PolyLine and adding the length of the closing segment
         return super.getLength()
                 + Math.hypot(Math.hypot(getX(size() - 1) - getX(0), getY(size() - 1) - getY(0)), getZ(size() - 1) - getZ(0));
     }
 
     @Override
     public LineSegment3d getSegment(final int index)
     {
         if (index < size() - 1)
         {
             return super.getSegment(index);
         }
         Throw.when(index != size() - 1, IndexOutOfBoundsException.class, "index must be in range [0, .size() - 1] (got %d)",
                 index);
         return new LineSegment3d(getX(index), getY(index), getZ(index), getX(0), getY(0), getZ(0));
     }
 
     @Override
     public Polygon2d project() throws InvalidProjectionException
     {
         double[] projectedX = new double[this.size()];
         double[] projectedY = new double[this.size()];
 
         int nextIndex = 0;
         for (int i = 0; i < this.size(); i++)
         {
             if (i > 0 && getX(i) == getX(i - 1) && getY(i) == getY(i - 1))
             {
                 continue;
             }
             projectedX[nextIndex] = getX(i);
             projectedY[nextIndex] = getY(i);
             nextIndex++;
         }
         Throw.when(nextIndex < 2, InvalidProjectionException.class,
                 "projection yielded too few points to construct a valid Polygon2d");
         if (nextIndex < projectedX.length)
         {
             return new Polygon2d(Arrays.copyOf(projectedX, nextIndex), Arrays.copyOf(projectedY, nextIndex));
         }
         return new Polygon2d(projectedX, projectedY);
     }
 
     @Override
     public Polygon3d reverse()
     {
         return new Polygon3d(super.reverse().iterator());
     }
 
     @Override
     public final String toString()
     {
         return toString("%f", false);
     }
 
     @Override
     public String toString(final String doubleFormat, final boolean doNotIncludeClassName)
     {
         StringBuilder result = new StringBuilder();
         if (!doNotIncludeClassName)
         {
             result.append("Polygon3d ");
         }
         result.append("[super=");
         result.append(super.toString(doubleFormat, false));
         result.append("]");
         return result.toString();
     }
 
 }