package org.opentrafficsim.road.network.sampling.data;
   
   import org.djunits.unit.SpeedUnit;
   import org.djunits.value.vfloat.scalar.FloatSpeed;
   import org.opentrafficsim.core.gtu.GTUException;
   import org.opentrafficsim.core.network.NetworkException;
   import org.opentrafficsim.kpi.interfaces.GtuDataInterface;
   import org.opentrafficsim.kpi.sampling.data.ExtendedDataTypeSpeed;
   import org.opentrafficsim.road.gtu.lane.LaneBasedGTU;
  import org.opentrafficsim.road.network.sampling.GtuData;
  
  import nl.tudelft.simulation.language.Throw;
  
  /**
   * <p>
   * Copyright (c) 2013-2017 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 21 nov. 2016 <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 class ReferenceSpeed extends ExtendedDataTypeSpeed
  {
  
      /**
       * 
       */
      public ReferenceSpeed()
      {
          super("referenceSpeed");
      }
  
      /** {@inheritDoc} */
      @Override
      public final FloatSpeed getValue(final GtuDataInterface gtu)
      {
          Throw.when(!(gtu instanceof GtuData), IllegalArgumentException.class,
                  "Extended data type ReferenceSpeed can only be used with GtuData.");
          LaneBasedGTU gtuObj = ((GtuData) gtu).getGtu();
          try
          {
              double v1 = gtuObj.getReferencePosition().getLane().getSpeedLimit(gtuObj.getGTUType()).si;
              double v2 = gtuObj.getMaximumSpeed().si;
              return new FloatSpeed(v1 < v2 ? v1 : v2, SpeedUnit.SI);
          }
          catch (GTUException exception)
          {
              // GTU was destroyed and is without a reference location
              return new FloatSpeed(Double.NaN, SpeedUnit.SI);
          }
          catch (NetworkException exception)
          {
              throw new RuntimeException("Could not obtain reference speed from GTU " + gtuObj, exception);
          }
      }
  
      /** {@inheritDoc} */
      @Override
      public String toString()
      {
          return "Reference Speed";
      }
  
  }