package org.opentrafficsim.road.network.lane;
   
   import java.io.Serializable;
   
   import org.djunits.value.vdouble.scalar.Length;
   import org.opentrafficsim.core.geometry.OTSLine3D;
   import org.opentrafficsim.core.gtu.GTUDirectionality;
   import org.opentrafficsim.core.gtu.GTUException;
   import org.opentrafficsim.core.network.LinkDirection;
  
  import nl.tudelft.simulation.language.Throw;
  import nl.tudelft.simulation.language.d3.DirectedPoint;
  
  /**
   * Store one position, direction and lane of a GTU.
   * <p>
   * Copyright (c) 2013-2018 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: 2015-07-24 02:58:59 +0200 (Fri, 24 Jul 2015) $, @version $Revision: 1147 $, by $Author: averbraeck $,
   * initial version Nov 11, 2015 <br>
   * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   * @author <a href="http://www.tudelft.nl/pknoppers">Peter Knoppers</a>
   */
  public class DirectedLanePosition implements Serializable
  {
      /** */
      private static final long serialVersionUID = 20151111L;
  
      /** The lane for the position. */
      private final Lane lane;
  
      /** The position on the lane, relative to the cross section link (design line). */
      private final Length position;
  
      /** The direction the vehicle is driving to -- either in the direction of the design line, or against it. */
      private final GTUDirectionality gtuDirection;
  
      /** Link direction. */
      private LinkDirection linkDirection = null;
  
      /**
       * Construct a new DirectedLanePosition.
       * @param lane Lane; the lane for the position
       * @param position Length; the position on the lane, relative to the cross section link (design line)
       * @param gtuDirection GTUDirectionality; the direction the vehicle is driving to -- either in the direction of the design
       *            line, or against it
       * @throws GTUException when preconditions fail
       */
      public DirectedLanePosition(final Lane lane, final Length position, final GTUDirectionality gtuDirection)
              throws GTUException
      {
          super();
          Throw.when(lane == null, GTUException.class, "lane is null");
          Throw.when(position == null, GTUException.class, "position is null");
          Throw.when(gtuDirection == null, GTUException.class, "gtuDirection is null");
          this.lane = lane;
          this.position = position;
          this.gtuDirection = gtuDirection;
      }
  
      /**
       * Retrieve the lane.
       * @return Lane; the lane for the position
       */
      public final Lane getLane()
      {
          return this.lane;
      }
  
      /**
       * Retrieve the position on the lane.
       * @return Length; the position on the lane, relative to the cross section link (design line)
       */
      public final Length getPosition()
      {
          return this.position;
      }
  
      /**
       * Retrieve the gtuDirection.
       * @return GTUDirectionality; gtuDirection the direction the vehicle is driving to -- either in the direction of the design
       *         line, or against it
       */
      public final GTUDirectionality getGtuDirection()
      {
          return this.gtuDirection;
      }
  
      /**
       * Retrieve the location and direction of the GTU on the lane.
       * @return DirectedPoint; the location and direction of the GTU on the lane
       */
      public final DirectedPoint getLocation()
      {
          // double fraction = this.position.si / this.lane.getParentLink().getLength().si;
          OTSLine3D centerLine = this.lane.getCenterLine();
          double centerLineLength = centerLine.getLengthSI();
          double fraction = this.position.si / centerLineLength;
         DirectedPoint p = centerLine.getLocationFractionExtended(fraction);
         if (this.gtuDirection.equals(GTUDirectionality.DIR_PLUS))
         {
             return p;
         }
         return new DirectedPoint(p.x, p.y, p.z, p.getRotX(), p.getRotY(), p.getRotZ() + Math.PI);
     }
     
     /**
      * Returns the lane direction in the direction of this lane direction.
      * @return lane direction in the direction of this lane direction
      */
     public final LaneDirection getLaneDirection()
     {
         return new LaneDirection(this.lane, this.gtuDirection);
     }
     
     /**
      * Returns the link direction in the direction of this lane direction.
      * @return link direction in the direction of this lane direction
      */
     public final LinkDirection getLinkDirection()
     {
         if (this.linkDirection == null)
         {
             this.linkDirection = new LinkDirection(this.lane.getParentLink(), this.gtuDirection);
         }
         return this.linkDirection;
     }
 
     /** {@inheritDoc} */
     @Override
     public int hashCode()
     {
         final int prime = 31;
         int result = 1;
         result = prime * result + ((this.gtuDirection == null) ? 0 : this.gtuDirection.hashCode());
         result = prime * result + ((this.lane == null) ? 0 : this.lane.hashCode());
         result = prime * result + ((this.position == null) ? 0 : this.position.hashCode());
         return result;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean equals(final Object obj)
     {
         if (this == obj)
             return true;
         if (obj == null)
             return false;
         if (getClass() != obj.getClass())
             return false;
         DirectedLanePosition other = (DirectedLanePosition) obj;
         if (this.gtuDirection != other.gtuDirection)
             return false;
         if (this.lane == null)
         {
             if (other.lane != null)
                 return false;
         }
         else if (!this.lane.equals(other.lane))
             return false;
         if (this.position == null)
         {
             if (other.position != null)
                 return false;
         }
         else if (!this.position.equals(other.position))
             return false;
         return true;
     }
 
     /** {@inheritDoc} */
     @Override
     public final String toString()
     {
         return "DirectedLanePosition [lane=" + this.lane + ", position=" + this.position + ", gtuDirection=" + this.gtuDirection
                 + "]";
     }
 
 }