package org.opentrafficsim.road.network.lane.object;
   
   import java.util.HashSet;
   import java.util.LinkedHashSet;
   import java.util.List;
   import java.util.Map;
   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.GTUDirectionality;
  import org.opentrafficsim.core.gtu.GTUType;
  import org.opentrafficsim.core.network.LongitudinalDirectionality;
  import org.opentrafficsim.core.network.NetworkException;
  import org.opentrafficsim.road.network.lane.CrossSectionElement;
  import org.opentrafficsim.road.network.lane.Lane;
  import org.opentrafficsim.road.network.lane.conflict.BusStopConflictRule;
  import org.opentrafficsim.road.network.lane.conflict.Conflict;
  
  import nl.tudelft.simulation.dsol.simulators.SimulatorInterface;
  
  /**
   * 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) 2013-2019 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 24 jan. 2017 <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 BusStop extends AbstractLaneBasedObject
  {
  
      /** */
      private static final long serialVersionUID = 20170124L;
  
      /** Line numbers. */
      private final Set<String> lines = new HashSet<>();
  
      /** Stop name. */
      private final String name;
  
      /** Stored conflicts downstream. */
      private Set<Conflict> conflicts = null;
  
      /**
       * @param id String; id
       * @param lane Lane; lane
       * @param longitudinalPosition Length; position
       * @param name String; name of stop
       * @param simulator SimulatorInterface.TimeDoubleUnit; the simulator to schedule on
       * @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 SimulatorInterface.TimeDoubleUnit simulator) throws NetworkException
      {
          super(id, lane, LongitudinalDirectionality.DIR_PLUS, longitudinalPosition,
                  LaneBasedObject.makeGeometry(lane, longitudinalPosition), Length.ZERO);
          this.name = name;
      }
  
      /**
       * Sets the lines.
       * @param lines Set&lt;String&gt;; 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
             GTUDirectionality dir = getDirection().isForward() ? GTUDirectionality.DIR_PLUS : GTUDirectionality.DIR_MINUS;
             Length position = getLongitudinalPosition();
             while (lane != null)
             {
                 List<LaneBasedObject> objects = lane.getObjectAhead(position, dir);
                 while (objects != null)
                 {
                     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(), dir);
                 }
                 Map<Lane, GTUDirectionality> downstreamLanes = lane.downstreamLanes(dir, GTUType.BUS);
                 int numLanes = 0;
                 for (Lane nextLane : downstreamLanes.keySet())
                 {
                     if (nextLane.getParentLink().getPriority().isBusStop())
                     {
                         numLanes++;
                         lane = nextLane;
                         dir = downstreamLanes.get(lane);
                         position = dir.isPlus() ? Length.ZERO : lane.getLength();
                     }
                 }
                 if (numLanes != 1)
                 {
                     lane = null;
                 }
             }
         }
         return this.conflicts;
     }
 
     /** {@inheritDoc} */
     @Override
     public final int hashCode()
     {
         final int prime = 31;
         int result = 1;
         result = prime * result + this.getId().hashCode();
         return result;
     }
 
     /** {@inheritDoc} */
     @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;
     }
 
     /** {@inheritDoc} */
     @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 + "]";
     }
 
     /** {@inheritDoc} */
     @Override
     public final AbstractLaneBasedObject clone(final CrossSectionElement newCSE,
             final SimulatorInterface.TimeDoubleUnit newSimulator) throws NetworkException
     {
         BusStop busStop = new BusStop(getId(), (Lane) newCSE, getLongitudinalPosition(), this.name, newSimulator);
         busStop.setLines(this.lines);
         return busStop;
     }
 
 }