package org.opentrafficsim.road.gtu.lane.tactical;
   
   import java.util.LinkedHashSet;
   import java.util.Set;
   
   import org.djunits.value.vdouble.scalar.Length;
   import org.djutils.immutablecollections.ImmutableSortedSet;
   import org.opentrafficsim.base.OtsRuntimeException;
   import org.opentrafficsim.base.parameters.ParameterException;
  import org.opentrafficsim.base.parameters.ParameterTypes;
  import org.opentrafficsim.core.gtu.plan.tactical.TacticalPlanner;
  import org.opentrafficsim.core.network.LateralDirectionality;
  import org.opentrafficsim.core.network.route.Route;
  import org.opentrafficsim.road.gtu.lane.LaneBasedGtu;
  import org.opentrafficsim.road.gtu.lane.perception.LanePerception;
  import org.opentrafficsim.road.gtu.lane.tactical.following.CarFollowingModel;
  import org.opentrafficsim.road.network.LaneAccessLaw;
  import org.opentrafficsim.road.network.LaneChangeInfo;
  import org.opentrafficsim.road.network.lane.Lane;
  
  /**
   * <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 interface LaneBasedTacticalPlanner extends TacticalPlanner<LaneBasedGtu, LanePerception>
  {
      /**
       * Returns the car-following model.
       * @return car following model
       */
      CarFollowingModel getCarFollowingModel();
  
      /**
       * Selects a lane from a possible set. This set contains all viable lanes in to which a lane splits.
       * @param from lane we come from
       * @param lanes set of lanes possible
       * @return preferred lane
       * @throws ParameterException in case of a missing parameter
       */
      default Lane chooseLaneAtSplit(final Lane from, final Set<Lane> lanes) throws ParameterException
      {
          Route route = getGtu().getStrategicalPlanner().getRoute()
                  .orElseThrow(() -> new OtsRuntimeException("Choosing lane at split without a route."));
          Length perception = getGtu().getParameters().getParameter(ParameterTypes.LANE_STRUCTURE);
          Set<Lane> bestRegardingRoute = new LinkedHashSet<>();
          LaneChangeInfo bestInfo = null;
          for (Lane lane : lanes)
          {
              ImmutableSortedSet<LaneChangeInfo> lcInfo =
                      lane.getNetwork().getLaneChangeInfo(lane, route, getGtu().getType(), perception, LaneAccessLaw.LEGAL);
              LaneChangeInfo info = lcInfo.isEmpty() ? null : lcInfo.first();
              int comp = bestInfo == null ? (info == null ? 0 : -info.compareTo(bestInfo)) : bestInfo.compareTo(info);
              if (comp >= 0)
              {
                  if (comp > 0)
                  {
                      bestRegardingRoute.clear();
                      bestInfo = info;
                  }
                  bestRegardingRoute.add(lane);
              }
          }
          if (bestRegardingRoute.size() > 1)
          {
              Lane rightMost = null;
              for (Lane lane : bestRegardingRoute)
              {
                  rightMost = rightMost == null ? lane : mostOnSide(rightMost, lane, LateralDirectionality.RIGHT);
              }
              return rightMost;
          }
          return bestRegardingRoute.iterator().next();
      }
  
      /**
       * Returns the right-most of two lanes.
       * @param lane1 lane 1
       * @param lane2 lane 2
       * @param lat lateral side
       * @return right-most of two lanes
       */
      static Lane mostOnSide(final Lane lane1, final Lane lane2, final LateralDirectionality lat)
      {
          Length offset1 = lane1.getOffsetAtBegin().plus(lane1.getOffsetAtEnd());
          Length offset2 = lane2.getOffsetAtBegin().plus(lane2.getOffsetAtEnd());
          if (lat.isLeft())
          {
              return offset1.gt(offset2) ? lane1 : lane2;
          }
          return offset1.gt(offset2) ? lane2 : lane1;
      }
  
  }