package org.opentrafficsim.road.gtu.tactical.lmrs;
   
   import org.djunits.value.vdouble.scalar.Length;
   import org.djunits.value.vdouble.scalar.Speed;
   import org.djutils.immutablecollections.ImmutableLinkedHashMap;
   import org.opentrafficsim.base.parameters.ParameterException;
   import org.opentrafficsim.base.parameters.ParameterTypeDouble;
   import org.opentrafficsim.base.parameters.ParameterTypeLength;
   import org.opentrafficsim.base.parameters.ParameterTypeSpeed;
  import org.opentrafficsim.base.parameters.ParameterTypes;
  import org.opentrafficsim.core.gtu.Stateless;
  import org.opentrafficsim.core.gtu.plan.operational.OperationalPlanException;
  import org.opentrafficsim.core.network.LateralDirectionality;
  import org.opentrafficsim.road.gtu.LaneBasedGtu;
  import org.opentrafficsim.road.gtu.perception.PerceptionCollectable;
  import org.opentrafficsim.road.gtu.perception.RelativeLane;
  import org.opentrafficsim.road.gtu.perception.categories.InfrastructurePerception;
  import org.opentrafficsim.road.gtu.perception.categories.neighbors.NeighborsPerception;
  import org.opentrafficsim.road.gtu.perception.object.PerceivedGtu;
  import org.opentrafficsim.road.gtu.tactical.TacticalContextEgo;
  import org.opentrafficsim.road.gtu.tactical.util.lmrs.Desire;
  import org.opentrafficsim.road.gtu.tactical.util.lmrs.LmrsParameters;
  import org.opentrafficsim.road.gtu.tactical.util.lmrs.Tailgating;
  import org.opentrafficsim.road.gtu.tactical.util.lmrs.VoluntaryIncentive;
  
  /**
   * Lane change incentive based on social pressure. Drivers may refrain from changing left to not hinder faster traffic, or
   * drivers may change right to get out of the way. When drivers are on the left lane, this is considered 'overtaking', and
   * related to this the desired speed could be increased by using {@code SocioDesiredSpeedModel}.
   * <p>
   * Copyright (c) 2013-2026 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 Alexander Verbraeck
   * @author Peter Knoppers
   * @author Wouter Schakel
   */
  // TODO keep left or right rules
  public final class IncentiveSocioSpeed implements VoluntaryIncentive, Stateless<IncentiveSocioSpeed>
  {
  
      /** Social pressure applied to the leader. */
      protected static final ParameterTypeDouble RHO = Tailgating.RHO;
  
      /** Hierarchy parameter. */
      protected static final ParameterTypeDouble SOCIO = LmrsParameters.SOCIO;
  
      /** Speed threshold below which traffic is considered congested. */
      protected static final ParameterTypeSpeed VCONG = ParameterTypes.VCONG;
  
      /** Vgain parameter; ego-speed sensitivity. */
      protected static final ParameterTypeSpeed VGAIN = LmrsParameters.VGAIN;
  
      /** Look-ahead distance. */
      protected static final ParameterTypeLength LOOKAHEAD = ParameterTypes.LOOKAHEAD;
  
      /** Singleton instance. */
      public static final IncentiveSocioSpeed SINGLETON = new IncentiveSocioSpeed();
  
      @Override
      public IncentiveSocioSpeed get()
      {
          return SINGLETON;
      }
  
      /**
       * Constructor.
       */
      private IncentiveSocioSpeed()
      {
          //
      }
  
      @Override
      public Desire determineDesire(final TacticalContextEgo context, final Desire mandatoryDesire,
              final ImmutableLinkedHashMap<Class<? extends VoluntaryIncentive>, Desire> voluntaryDesire)
              throws ParameterException, OperationalPlanException
      {
          double dLeft = 0;
          double dRight = 0;
          if (context.getSpeed().gt(context.getParameters().getParameter(VCONG)))
          {
              double sigma = context.getParameters().getParameter(SOCIO);
              NeighborsPerception neighbors = context.getPerception().getPerceptionCategory(NeighborsPerception.class);
              InfrastructurePerception infra = context.getPerception().getPerceptionCategory(InfrastructurePerception.class);
              boolean leftLane = infra.getLegalLaneChangePossibility(RelativeLane.CURRENT, LateralDirectionality.LEFT).si > 0.0;
              boolean rightLane = infra.getLegalLaneChangePossibility(RelativeLane.CURRENT, LateralDirectionality.RIGHT).si > 0.0;
              // change right to get out of the way
              if (rightLane && mandatoryDesire.right() >= 0.0)
              {
                  PerceptionCollectable<PerceivedGtu, LaneBasedGtu> followers = neighbors.getFollowers(RelativeLane.CURRENT);
                  if (!followers.isEmpty())
                  {
                      double rho = context.getParameters().getParameter(RHO);
                      PerceivedGtu follower = followers.first();
                      double rhoFollower = follower.getBehavior().getParameters().getParameter(RHO);
                      if (rhoFollower * sigma > rho)
                      {
                          dRight = rhoFollower * sigma;
                     }
                 }
             }
             // stay right to keep out of the way
             if (leftLane && mandatoryDesire.left() <= 0.0)
             {
                 PerceptionCollectable<PerceivedGtu, LaneBasedGtu> followers = neighbors.getFollowers(RelativeLane.LEFT);
                 if (followers != null && !followers.isEmpty())
                 {
                     double rho;
                     PerceptionCollectable<PerceivedGtu, LaneBasedGtu> leaders = neighbors.getLeaders(RelativeLane.LEFT);
                     if (leaders != null && !leaders.isEmpty())
                     {
                         PerceivedGtu leader = leaders.first();
                         Speed vDes = context.getDesiredSpeed();
                         Speed vGain = context.getParameters().getParameter(VGAIN);
                         Length x0 = context.getParameters().getParameter(LOOKAHEAD);
                         rho = Tailgating.socialPressure(vDes, leader.getSpeed(), vGain, leader.getDistance(), x0);
                     }
                     else
                     {
                         rho = 0.0;
                     }
                     PerceivedGtu follower = followers.first();
                     Speed vGainFollower = follower.getBehavior().getParameters().getParameter(VGAIN);
                     Length x0Follower = follower.getBehavior().getParameters().getParameter(LOOKAHEAD);
                     double rhoFollower = Tailgating.socialPressure(follower.getBehavior().getDesiredSpeed(), context.getSpeed(),
                             vGainFollower, follower.getDistance(), x0Follower);
                     if (rhoFollower * sigma > rho)
                     {
                         dLeft = -rhoFollower * sigma;
                     }
                 }
             }
         }
         return new Desire(dLeft, dRight);
     }
 
     @Override
     public String toString()
     {
         return "IncentiveSocioSpeed";
     }
 
 }