package org.opentrafficsim.road.gtu.lane.perception.categories;
   
   import org.djunits.value.vdouble.scalar.Duration;
   import org.djunits.value.vdouble.scalar.Length;
   import org.djunits.value.vdouble.scalar.Time;
   import org.opentrafficsim.base.parameters.ParameterException;
   import org.opentrafficsim.base.parameters.ParameterTypes;
   import org.opentrafficsim.core.gtu.GTUException;
   import org.opentrafficsim.road.gtu.lane.LaneBasedGTU;
  import org.opentrafficsim.road.gtu.lane.perception.categories.Anticipation.NeighborTriplet;
  import org.opentrafficsim.road.gtu.lane.perception.headway.HeadwayGTU;
  import org.opentrafficsim.road.gtu.lane.perception.headway.HeadwayGTUPerceived;
  import org.opentrafficsim.road.gtu.lane.perception.headway.HeadwayGTUReal;
  import org.opentrafficsim.road.gtu.lane.perception.headway.HeadwayGTURealCopy;
  
  /**
   * Whether a GTU needs to be wrapped, or information should be copied for later and unaltered use.
   * <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/node/13">OpenTrafficSim License</a>.
   * <p>
   * @version $Revision$, $LastChangedDate$, by $Author$, initial version 24 mrt. 2017 <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.transport.citg.tudelft.nl">Wouter Schakel</a>
   */
  public interface HeadwayGtuType
  {
  
      /** The GTU is wrapped, and info is taken directly from it. */
      public final static HeadwayGtuType WRAP = new HeadwayGtuType()
      {
          @Override
          public HeadwayGTUReal createHeadwayGtu(final LaneBasedGTU perceivingGtu, final LaneBasedGTU perceivedGtu,
                  final Length distance, final boolean downstream) throws GTUException
          {
              return new HeadwayGTUReal(perceivedGtu, distance, true);
          }
  
          @Override
          public HeadwayGTUReal createHeadwayGtu(final LaneBasedGTU perceivingGtu, final LaneBasedGTU perceivedGtu,
                  final Length overlapFront, final Length overlap, final Length overlapRear) throws GTUException
          {
              return new HeadwayGTUReal(perceivedGtu, overlapFront, overlap, overlapRear, true);
          }
      };
  
      /** Info regarding the GTU is copied. */
      public final static HeadwayGtuType COPY = new HeadwayGtuType()
      {
          @Override
          public HeadwayGTURealCopy createHeadwayGtu(final LaneBasedGTU perceivingGtu, final LaneBasedGTU perceivedGtu,
                  final Length distance, final boolean downstream) throws GTUException
          {
              return new HeadwayGTURealCopy(perceivedGtu, distance);
          }
  
          @Override
          public HeadwayGTURealCopy createHeadwayGtu(final LaneBasedGTU perceivingGtu, final LaneBasedGTU perceivedGtu,
                  final Length overlapFront, final Length overlap, final Length overlapRear) throws GTUException
          {
              return new HeadwayGTURealCopy(perceivedGtu, overlapFront, overlap, overlapRear);
          }
      };
  
      /**
       * Creates a headway object from a GTU, downstream or upstream.
       * @param perceivingGtu perceiving GTU
       * @param perceivedGtu perceived GTU
       * @param distance distance
       * @param downstream downstream (or upstream) neighbor
       * @return headway object from a gtu
       * @throws GTUException when headway object cannot be created
       * @throws ParameterException on invalid parameter value or missing parameter
       */
      HeadwayGTU createHeadwayGtu(LaneBasedGTU perceivingGtu, LaneBasedGTU perceivedGtu, Length distance, boolean downstream)
              throws GTUException, ParameterException;
  
      /**
       * Creates a headway object from a GTU, parallel.
       * @param perceivingGtu perceiving GTU
       * @param perceivedGtu perceived GTU
       * @param overlapFront front overlap
       * @param overlap overlap
       * @param overlapRear rear overlap
       * @return headway object from a gtu
       * @throws GTUException when headway object cannot be created
       */
      HeadwayGTU createHeadwayGtu(LaneBasedGTU perceivingGtu, LaneBasedGTU perceivedGtu, Length overlapFront, Length overlap,
              Length overlapRear) throws GTUException;
  
      /**
       * Class for perceived neighbors. Adjacent neighbors are perceived exactly.
       * <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/node/13">OpenTrafficSim License</a>.
       * <p>
       * @version $Revision$, $LastChangedDate$, by $Author$, initial version 6 apr. 2018 <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.transport.citg.tudelft.nl">Wouter Schakel</a>
      */
     class PerceivedHeadwayGtuType implements HeadwayGtuType
     {
 
         /** Estimation. */
         private final Estimation estimation;
 
         /** Anticipation. */
         private final Anticipation anticipation;
 
         /** Last update time. */
         private Time updateTime = null;
 
         /** Reaction time at update time. */
         private Duration tr;
 
         /** Historical moment considered at update time. */
         private Time when;
 
         /** Traveled distance during reaction time at update time. */
         private Length traveledDistance;
 
         /**
          * Constructor.
          * @param estimation Estimation; estimation
          * @param anticipation Anticipation; anticipation
          */
         public PerceivedHeadwayGtuType(final Estimation estimation, final Anticipation anticipation)
         {
             this.estimation = estimation;
             this.anticipation = anticipation;
         }
 
         /** {@inheritDoc} */
         @Override
         public HeadwayGTU createHeadwayGtu(final LaneBasedGTU perceivingGtu, final LaneBasedGTU perceivedGtu,
                 final Length distance, final boolean downstream) throws GTUException, ParameterException
         {
             Time now = perceivedGtu.getSimulator().getSimulatorTime();
             if (this.updateTime == null || now.si > this.updateTime.si)
             {
                 this.updateTime = now;
                 this.tr = perceivingGtu.getParameters().getParameter(ParameterTypes.TR);
                 Time whenTemp = now.minus(this.tr);
                 if (this.when == null || (this.when != null && whenTemp.si > this.when.si))
                 {
                     // never go backwards in time if the reaction time increases
                     this.when = whenTemp;
                 }
                 this.traveledDistance = perceivingGtu.getOdometer().minus(perceivingGtu.getOdometer(this.when));
             }
             NeighborTriplet triplet = this.estimation.estimate(perceivingGtu, perceivedGtu, distance, downstream, this.when);
             triplet = this.anticipation.anticipate(triplet, this.tr, this.traveledDistance);
             return new HeadwayGTUPerceived(perceivedGtu, triplet.getHeadway(), triplet.getSpeed(), triplet.getAcceleration());
         }
 
         /** {@inheritDoc} */
         @Override
         public HeadwayGTU createHeadwayGtu(final LaneBasedGTU perceivingGtu, final LaneBasedGTU perceivedGtu,
                 final Length overlapFront, final Length overlap, final Length overlapRear) throws GTUException
         {
             return new HeadwayGTUPerceived(perceivedGtu, overlapFront, overlap, overlapRear, perceivedGtu.getSpeed(),
                     perceivedGtu.getAcceleration());
         }
 
     }
 
 }