package org.opentrafficsim.road.network.lane;
   
   import java.io.Serializable;
   
   import javax.media.j3d.Bounds;
   
   import nl.tudelft.simulation.dsol.animation.LocatableInterface;
   import nl.tudelft.simulation.language.d3.DirectedPoint;
   
  import org.opentrafficsim.core.OTS_SCALAR;
  import org.opentrafficsim.core.geometry.OTSBuffering;
  import org.opentrafficsim.core.geometry.OTSGeometryException;
  import org.opentrafficsim.core.geometry.OTSLine3D;
  import org.opentrafficsim.core.geometry.OTSPoint3D;
  import org.opentrafficsim.core.network.LateralDirectionality;
  import org.opentrafficsim.core.network.NetworkException;
  
  /**
   * <p>
   * Copyright (c) 2013-2015 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="http://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
   * <p>
   * $LastChangedDate: 2015-09-14 01:33:02 +0200 (Mon, 14 Sep 2015) $, @version $Revision: 1401 $, by $Author: averbraeck $,
   * initial version Aug 19, 2014 <br>
   * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   * @author <a href="http://www.tudelft.nl/pknoppers">Peter Knoppers</a>
   * @author <a href="http://www.citg.tudelft.nl">Guus Tamminga</a>
   */
  public abstract class CrossSectionElement implements LocatableInterface, Serializable, OTS_SCALAR
  {
      /** */
      private static final long serialVersionUID = 20150826L;
  
      /** the id. Should be unique within the parentLink. */
      private final String id;
  
      /** Cross Section Link to which the element belongs. */
      @SuppressWarnings("checkstyle:visibilitymodifier")
      protected final CrossSectionLink parentLink;
  
      /** The lateral offset from the design line of the parentLink at the start of the parentLink. */
      @SuppressWarnings("checkstyle:visibilitymodifier")
      protected final Length.Rel designLineOffsetAtBegin;
  
      /** The lateral offset from the design line of the parentLink at the end of the parentLink. */
      @SuppressWarnings("checkstyle:visibilitymodifier")
      protected final Length.Rel designLineOffsetAtEnd;
  
      /** Start width, positioned <i>symmetrically around</i> the lateral start position. */
      @SuppressWarnings("checkstyle:visibilitymodifier")
      protected final Length.Rel beginWidth;
  
      /** End width, positioned <i>symmetrically around</i> the lateral end position. */
      @SuppressWarnings("checkstyle:visibilitymodifier")
      protected final Length.Rel endWidth;
  
      /** The length of the line. Calculated once at the creation. */
      @SuppressWarnings("checkstyle:visibilitymodifier")
      protected final Length.Rel length;
  
      /** The center line of the element. Calculated once at the creation. */
      private final OTSLine3D centerLine;
  
      /** The contour of the element. Calculated once at the creation. */
      private final OTSLine3D contour;
  
      /**
       * <b>Note:</b> LEFT is seen as a positive lateral direction, RIGHT as a negative lateral direction, with the direction from
       * the StartNode towards the EndNode as the longitudinal direction.
       * @param id String; The id of the CrosssSectionElement. Should be unique within the parentLink.
       * @param parentLink CrossSectionLink; Link to which the element belongs.
       * @param lateralOffsetAtBegin DoubleScalar.Rel&lt;LengthUnit&gt;; the lateral offset of the design line of the new
       *            CrossSectionLink with respect to the design line of the parent Link at the start of the parent Link
       * @param lateralOffsetAtEnd DoubleScalar.Rel&lt;LengthUnit&gt;; the lateral offset of the design line of the new
       *            CrossSectionLink with respect to the design line of the parent Link at the end of the parent Link
       * @param beginWidth DoubleScalar.Rel&lt;LengthUnit&gt;; width at start, positioned <i>symmetrically around</i> the design
       *            line
       * @param endWidth DoubleScalar.Rel&lt;LengthUnit&gt;; width at end, positioned <i>symmetrically around</i> the design line
       * @throws OTSGeometryException when creation of the geometry fails
       * @throws NetworkException when id equal to null or not unique
       */
      public CrossSectionElement(final CrossSectionLink parentLink, final String id, final Length.Rel lateralOffsetAtBegin,
          final Length.Rel lateralOffsetAtEnd, final Length.Rel beginWidth, final Length.Rel endWidth)
          throws OTSGeometryException, NetworkException
      {
          super();
          if (id == null)
          {
              throw new NetworkException("Constructor of CrossSectionElement -- id cannot be null");
          }
          for (CrossSectionElement cse : parentLink.getCrossSectionElementList())
          {
              if (cse.getId().equals(id))
              {
                  throw new NetworkException("Constructor of CrossSectionElement -- id " + id + " not unique within the Link");
              }
          }
          this.id = id;
          this.parentLink = parentLink;
         this.designLineOffsetAtBegin = lateralOffsetAtBegin;
         this.designLineOffsetAtEnd = lateralOffsetAtEnd;
         this.beginWidth = beginWidth;
         this.endWidth = endWidth;
 
         this.centerLine =
             OTSBuffering.offsetLine(this.getParentLink().getDesignLine(), this.designLineOffsetAtBegin.getSI(),
                 this.designLineOffsetAtEnd.getSI());
         this.length = this.centerLine.getLength();
         this.contour = constructContour(this);
 
         this.parentLink.addCrossSectionElement(this);
     }
 
     /**
      * @return parentLink.
      */
     public final CrossSectionLink getParentLink()
     {
         return this.parentLink;
     }
 
     /**
      * Retrieve the lateral offset from the Link design line at the specified longitudinal position.
      * @param fractionalPosition double; fractional longitudinal position on this Lane
      * @return DoubleScalar.Rel&lt;LengthUnit&gt; the lateralCenterPosition at the specified longitudinal position
      */
     public final Length.Rel getLateralCenterPosition(final double fractionalPosition)
     {
         return Length.Rel.interpolate(this.designLineOffsetAtBegin, this.designLineOffsetAtEnd, fractionalPosition);
     }
 
     /**
      * Retrieve the lateral offset from the Link design line at the specified longitudinal position.
      * @param longitudinalPosition DoubleScalar.Rel&lt;LengthUnit&gt;; the longitudinal position on this Lane
      * @return DoubleScalar.Rel&lt;LengthUnit&gt; the lateralCenterPosition at the specified longitudinal position
      */
     public final Length.Rel getLateralCenterPosition(final Length.Rel longitudinalPosition)
     {
         return getLateralCenterPosition(longitudinalPosition.getSI() / getLength().getSI());
     }
 
     /**
      * Return the width of this CrossSectionElement at a specified longitudinal position.
      * @param longitudinalPosition DoubleScalar&lt;LengthUnit&gt;; the longitudinal position
      * @return DoubleScalar.Rel&lt;LengthUnit&gt;; the width of this CrossSectionElement at the specified longitudinal position.
      */
     public final Length.Rel getWidth(final Length.Rel longitudinalPosition)
     {
         return getWidth(longitudinalPosition.getSI() / getLength().getSI());
     }
 
     /**
      * Return the width of this CrossSectionElement at a specified fractional longitudinal position.
      * @param fractionalPosition double; the fractional longitudinal position
      * @return DoubleScalar.Rel&lt;LengthUnit&gt;; the width of this CrossSectionElement at the specified fractional
      *         longitudinal position.
      */
     public final Length.Rel getWidth(final double fractionalPosition)
     {
         return Length.Rel.interpolate(this.beginWidth, this.endWidth, fractionalPosition);
     }
 
     /**
      * Return the length of this CrossSectionElement as measured along the design line (which equals the center line).
      * @return DoubleScalar.Rel&lt;LengthUnit&gt;; the length of this CrossSectionElement
      */
     public final Length.Rel getLength()
     {
         return this.length;
     }
 
     /**
      * @return designLineOffsetAtBegin.
      */
     public final Length.Rel getDesignLineOffsetAtBegin()
     {
         return this.designLineOffsetAtBegin;
     }
 
     /**
      * @return designLineOffsetAtEnd.
      */
     public final Length.Rel getDesignLineOffsetAtEnd()
     {
         return this.designLineOffsetAtEnd;
     }
 
     /**
      * @return beginWidth.
      */
     public final Length.Rel getBeginWidth()
     {
         return this.beginWidth;
     }
 
     /**
      * @return endWidth.
      */
     public final Length.Rel getEndWidth()
     {
         return this.endWidth;
     }
 
     /**
      * @return the z-offset for drawing (what's on top, what's underneath).
      */
     protected abstract double getZ();
 
     /**
      * @return centerLine.
      */
     public final OTSLine3D getCenterLine()
     {
         return this.centerLine;
     }
 
     /**
      * @return contour.
      */
     public final OTSLine3D getContour()
     {
         return this.contour;
     }
 
     /**
      * @return id
      */
     public final String getId()
     {
         return this.id;
     }
 
     /**
      * Return the lateral offset from the design line of the parent Link of the Left or Right boundary of this
      * CrossSectionElement at the specified fractional longitudinal position.
      * @param lateralDirection LateralDirectionality; LEFT, or RIGHT
      * @param fractionalLongitudinalPosition double; ranges from 0.0 (begin of parentLink) to 1.0 (end of parentLink)
      * @return DoubleScalar.Rel&lt;LengthUnit&gt;
      */
     public final Length.Rel getLateralBoundaryPosition(final LateralDirectionality lateralDirection,
         final double fractionalLongitudinalPosition)
     {
         Length.Rel designLineOffset =
             Length.Rel.interpolate(this.designLineOffsetAtBegin, this.designLineOffsetAtEnd, fractionalLongitudinalPosition);
         Length.Rel halfWidth =
             Length.Rel.interpolate(this.beginWidth, this.endWidth, fractionalLongitudinalPosition).multiplyBy(0.5);
         switch (lateralDirection)
         {
             case LEFT:
                 return designLineOffset.minus(halfWidth);
             case RIGHT:
                 return designLineOffset.plus(halfWidth);
             default:
                 throw new Error("Bad switch on LateralDirectionality " + lateralDirection);
         }
     }
 
     /**
      * Return the lateral offset from the design line of the parent Link of the Left or Right boundary of this
      * CrossSectionElement at the specified longitudinal position.
      * @param lateralDirection LateralDirectionality; LEFT, or RIGHT
      * @param longitudinalPosition DoubleScalar.Rel&lt;LengthUnit&gt;; the position along the length of this CrossSectionElement
      * @return DoubleScalar.Rel&lt;LengthUnit&gt;
      */
     public final Length.Rel getLateralBoundaryPosition(final LateralDirectionality lateralDirection,
         final Length.Rel longitudinalPosition)
     {
         return getLateralBoundaryPosition(lateralDirection, longitudinalPosition.getSI() / getLength().getSI());
     }
 
 
     /**
      * Construct a buffer geometry by offsetting the linear geometry line with a distance and constructing a so-called "buffer"
      * around it.
      * @param cse the CrossSectionElement to construct the contour for
      * @return the geometry belonging to this CrossSectionElement.
      * @throws OTSGeometryException when construction of the geometry fails
      */
     public static OTSLine3D constructContour(final CrossSectionElement cse) throws OTSGeometryException
     {
         OTSLine3D crossSectionDesignLine =
             OTSBuffering.offsetLine(cse.getParentLink().getDesignLine(), cse.getDesignLineOffsetAtBegin().getSI(), cse
                 .getDesignLineOffsetAtEnd().getSI());
         OTSLine3D rightBoundary =
                 OTSBuffering.offsetLine(crossSectionDesignLine, -cse.getBeginWidth().getSI() / 2, -cse.getEndWidth().getSI() / 2);
         OTSLine3D leftBoundary =
                 OTSBuffering.offsetLine(crossSectionDesignLine, cse.getBeginWidth().getSI() / 2, cse.getEndWidth().getSI() / 2);
         OTSPoint3D[] result = new OTSPoint3D[rightBoundary.size() + leftBoundary.size() + 1];
         int resultIndex = 0;
         for (int index = 0; index < rightBoundary.size(); index++)
         {
             result[resultIndex++] = rightBoundary.get(index);
         }
         for (int index = leftBoundary.size(); --index >= 0;)
         {
             result[resultIndex++] = leftBoundary.get(index);
         }
         result[resultIndex] = rightBoundary.get(0); // close the contour
         return new OTSLine3D(result);
     }
 
     /** {@inheritDoc} */
     @Override
     @SuppressWarnings("checkstyle:designforextension")
     public DirectedPoint getLocation() 
     {
         DirectedPoint centroid = this.contour.getLocation();
         return new DirectedPoint(centroid.x, centroid.y, getZ());
     }
 
     /** {@inheritDoc} */
     @Override
     @SuppressWarnings("checkstyle:designforextension")
     public Bounds getBounds() 
     {
         return this.contour.getBounds();
     }
 
     /** {@inheritDoc} */
     @Override
     @SuppressWarnings("checkstyle:designforextension")
     public String toString()
     {
         return String.format("CSE offset %.2fm..%.2fm, width %.2fm..%.2fm", this.designLineOffsetAtBegin.getSI(),
             this.designLineOffsetAtEnd.getSI(), this.beginWidth.getSI(), this.endWidth.getSI());
     }
 
     /** {@inheritDoc} */
     @SuppressWarnings("checkstyle:designforextension")
     @Override
     public int hashCode()
     {
         final int prime = 31;
         int result = 1;
         result = prime * result + ((this.id == null) ? 0 : this.id.hashCode());
         result = prime * result + ((this.parentLink == null) ? 0 : this.parentLink.hashCode());
         return result;
     }
 
     /** {@inheritDoc} */
     @SuppressWarnings({"checkstyle:designforextension", "checkstyle:needbraces"})
     @Override
     public boolean equals(final Object obj)
     {
         if (this == obj)
             return true;
         if (obj == null)
             return false;
         if (getClass() != obj.getClass())
             return false;
         CrossSectionElement other = (CrossSectionElement) obj;
         if (this.id == null)
         {
             if (other.id != null)
                 return false;
         }
         else if (!this.id.equals(other.id))
             return false;
         if (this.parentLink == null)
         {
             if (other.parentLink != null)
                 return false;
         }
         else if (!this.parentLink.equals(other.parentLink))
             return false;
         return true;
     }
 
 }