package org.opentrafficsim.road.network.lane.object;
   
   import java.util.LinkedHashSet;
   import java.util.List;
   import java.util.Set;
   
   import org.djunits.value.vdouble.scalar.Length;
   import org.djutils.immutablecollections.Immutable;
   import org.djutils.immutablecollections.ImmutableHashSet;
  import org.djutils.immutablecollections.ImmutableSet;
  import org.opentrafficsim.core.gtu.GtuType;
  import org.opentrafficsim.core.network.NetworkException;
  import org.opentrafficsim.road.network.lane.Lane;
  import org.opentrafficsim.road.network.lane.conflict.BusStopConflictRule;
  import org.opentrafficsim.road.network.lane.conflict.Conflict;
  
  /**
   * A bus stop is a location on a lane. The stop has a name, and a set of lines. At a single stop in reality, there may be
   * different locations where busses stop for different lines. A {@code BusStop} pertains to only one such location. The bus stop
   * in reality is represented by a shared name over a few {@code BusStop}'s, with different lines. As lines may also be set
   * dynamically, the name and lines are insufficient to identify a specific {@code BusStop}. Hence there is a fixed unique id per
   * {@code BusStop}.
   * <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 class BusStop extends AbstractLaneBasedObject
  {
  
      /** Line numbers. */
      private final Set<String> lines = new LinkedHashSet<>();
  
      /** Stop name. */
      private final String name;
  
      /** Stored conflicts downstream. */
      private Set<Conflict> conflicts = null;
  
      /** Bus type. */
      private final GtuType busType;
  
      /**
       * Constructor.
       * @param id id
       * @param lane lane
       * @param longitudinalPosition position
       * @param name name of stop
       * @param busType bus type.
       * @throws NetworkException when the position on the lane is out of bounds
       */
      public BusStop(final String id, final Lane lane, final Length longitudinalPosition, final String name,
              final GtuType busType) throws NetworkException
      {
          super(id, lane, longitudinalPosition, LaneBasedObject.makeLine(lane, longitudinalPosition), Length.ZERO);
          this.name = name;
          this.busType = busType;
          init();
      }
  
      /**
       * Sets the lines.
       * @param lines lines that stop at this location
       */
      public final void setLines(final Set<String> lines)
      {
          this.lines.clear();
          this.lines.addAll(lines);
      }
  
      /**
       * Returns the lines set.
       * @return whether the lines belongs to this stop
       */
      public final ImmutableSet<String> getLines()
      {
          return new ImmutableHashSet<>(this.lines, Immutable.COPY);
      }
  
      /**
       * Returns the downstream conflicts of the bus stop. Search is only performed over links with BUS_STOP priority.
       * @return downstream conflicts of the given conflict
       */
      public final Set<Conflict> getConflicts()
      {
          if (this.conflicts == null)
          {
              this.conflicts = new LinkedHashSet<>();
              Lane lane = getLane();
              // conflict forces only plus or minus as direction
              Length position = getLongitudinalPosition();
              while (lane != null)
              {
                  List<LaneBasedObject> objects = lane.getObjectAhead(position);
                  while (!objects.isEmpty())
                  {
                     for (LaneBasedObject object : objects)
                     {
                         if (object instanceof Conflict)
                         {
                             Conflict conflict = (Conflict) object;
                             if (conflict.getConflictRule() instanceof BusStopConflictRule)
                             {
                                 this.conflicts.add(conflict);
                             }
                         }
                     }
                     objects = lane.getObjectAhead(objects.get(0).getLongitudinalPosition());
                 }
                 //
                 Set<Lane> downstreamLanes = lane.nextLanes(this.busType);
                 int numLanes = 0;
                 for (Lane nextLane : downstreamLanes)
                 {
                     if (nextLane.getLink().getPriority().isBusStop())
                     {
                         numLanes++;
                         lane = nextLane;
                         position = Length.ZERO;
                     }
                 }
                 if (numLanes != 1)
                 {
                     lane = null;
                 }
             }
         }
         return this.conflicts;
     }
 
     @Override
     public final int hashCode()
     {
         final int prime = 31;
         int result = 1;
         result = prime * result + this.getId().hashCode();
         return result;
     }
 
     @Override
     public final boolean equals(final Object obj)
     {
         if (this == obj)
         {
             return true;
         }
         if (obj == null)
         {
             return false;
         }
         if (getClass() != obj.getClass())
         {
             return false;
         }
         BusStop other = (BusStop) obj;
         if (!this.getId().equals(other.getId()))
         {
             return false;
         }
         return true;
     }
 
     @Override
     public final String toString()
     {
         String out = "BusStop [id=" + getId() + ", lines=";
         String delim = "";
         for (String line : this.lines)
         {
             out = out + delim + line;
             delim = "/";
         }
         return out + "]";
     }
 
 }