package org.opentrafficsim.road.gtu.lane.tactical.lmrs;
   
   import java.util.SortedSet;
   
   import org.djunits.value.vdouble.scalar.Speed;
   import org.opentrafficsim.base.parameters.ParameterException;
   import org.opentrafficsim.base.parameters.Parameters;
   import org.opentrafficsim.core.gtu.Stateless;
   import org.opentrafficsim.core.gtu.perception.EgoPerception;
  import org.opentrafficsim.core.gtu.plan.operational.OperationalPlanException;
  import org.opentrafficsim.core.network.LateralDirectionality;
  import org.opentrafficsim.road.gtu.lane.perception.LanePerception;
  import org.opentrafficsim.road.gtu.lane.perception.RelativeLane;
  import org.opentrafficsim.road.gtu.lane.perception.categories.InfrastructurePerception;
  import org.opentrafficsim.road.gtu.lane.tactical.following.CarFollowingModel;
  import org.opentrafficsim.road.gtu.lane.tactical.util.lmrs.Desire;
  import org.opentrafficsim.road.gtu.lane.tactical.util.lmrs.LmrsParameters;
  import org.opentrafficsim.road.gtu.lane.tactical.util.lmrs.VoluntaryIncentive;
  import org.opentrafficsim.road.network.LaneChangeInfo;
  
  /**
   * Incentive for trucks to remain on the two right-hand lanes, unless the route requires otherwise.
   * <p>
   * Copyright (c) 2013-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
   * </p>
   * @author <a href="https://github.com/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 final class IncentiveStayRight implements VoluntaryIncentive, Stateless<IncentiveStayRight>
  {
  
      /** Singleton instance. */
      public static final IncentiveStayRight SINGLETON = new IncentiveStayRight();
  
      @Override
      public IncentiveStayRight get()
      {
          return SINGLETON;
      }
  
      /**
       * Constructor.
       */
      private IncentiveStayRight()
      {
          //
      }
  
      @Override
      public Desire determineDesire(final Parameters parameters, final LanePerception perception,
              final CarFollowingModel carFollowingModel, final Desire mandatoryDesire, final Desire voluntaryDesire)
              throws ParameterException, OperationalPlanException
      {
          InfrastructurePerception infra = perception.getPerceptionCategory(InfrastructurePerception.class);
          // start at left-most lane
          SortedSet<RelativeLane> rootCrossSection = perception.getLaneStructure().getRootCrossSection();
          RelativeLane lane = rootCrossSection.first();
          // move right until we find 'the right-hand lane', which is defined by the last lane where the urgency does not increase
          Speed speed = perception.getPerceptionCategory(EgoPerception.class).getSpeed();
          double curUrgency = urgency(infra.getLegalLaneChangeInfo(lane), parameters, speed);
          double rightUrgency;
          RelativeLane right;
          while (rootCrossSection.contains(right = lane.getRight())
                  && (rightUrgency = urgency(infra.getLegalLaneChangeInfo(right), parameters, speed)) <= curUrgency)
          {
              curUrgency = rightUrgency;
              lane = right;
          }
          boolean legalLeft = infra.getLegalLaneChangePossibility(RelativeLane.CURRENT, LateralDirectionality.LEFT).ge0();
          if (lane.getLateralDirectionality().isRight() && lane.getNumLanes() > 1)
          {
              // must change right
              return new Desire(legalLeft ? -1.0 : 0.0, parameters.getParameter(LmrsParameters.DSYNC));
          }
          if (lane.isRight())
          {
              // must not change left
              return new Desire(legalLeft ? -1.0 : 0.0, 0.0);
          }
          return new Desire(0.0, 0.0);
      }
  
      /**
       * Returns the urgency to leave a lane.
       * @param laneChangeInfo lane change info on the lane
       * @param parameters parameters
       * @param speed current speed
       * @return urgency to leave the lane
       * @throws ParameterException if parameter is not given
       */
      private double urgency(final SortedSet<LaneChangeInfo> laneChangeInfo, final Parameters parameters, final Speed speed)
              throws ParameterException
      {
          double urgency = 0.0;
          for (LaneChangeInfo info : laneChangeInfo)
          {
              double nextUrgency =
                     IncentiveRoute.getDesireToLeave(parameters, info.remainingDistance(), info.numberOfLaneChanges(), speed);
             urgency = urgency > nextUrgency ? urgency : nextUrgency;
         }
         return urgency;
     }
 
     @Override
     public String toString()
     {
         return "IncentiveStayRight";
     }
 
 }