package org.opentrafficsim.road.network.sampling;
   
   import java.rmi.RemoteException;
   import java.util.LinkedHashMap;
   import java.util.LinkedHashSet;
   import java.util.Map;
   import java.util.Set;
   
   import org.djunits.unit.DurationUnit;
  import org.djunits.value.vdouble.scalar.Acceleration;
  import org.djunits.value.vdouble.scalar.Duration;
  import org.djunits.value.vdouble.scalar.Frequency;
  import org.djunits.value.vdouble.scalar.Length;
  import org.djunits.value.vdouble.scalar.Speed;
  import org.djunits.value.vdouble.scalar.Time;
  import org.djutils.event.Event;
  import org.djutils.event.EventListener;
  import org.djutils.event.TimedEvent;
  import org.djutils.event.reference.ReferenceType;
  import org.djutils.exceptions.Throw;
  import org.djutils.exceptions.Try;
  import org.opentrafficsim.core.dsol.OtsSimulatorInterface;
  import org.opentrafficsim.core.gtu.GtuException;
  import org.opentrafficsim.core.gtu.RelativePosition;
  import org.opentrafficsim.kpi.sampling.Sampler;
  import org.opentrafficsim.kpi.sampling.data.ExtendedDataType;
  import org.opentrafficsim.kpi.sampling.filter.FilterDataType;
  import org.opentrafficsim.road.gtu.lane.LaneBasedGtu;
  import org.opentrafficsim.road.network.RoadNetwork;
  import org.opentrafficsim.road.network.lane.CrossSectionLink;
  import org.opentrafficsim.road.network.lane.Lane;
  
  import nl.tudelft.simulation.dsol.SimRuntimeException;
  import nl.tudelft.simulation.dsol.formalisms.eventscheduling.SimEventInterface;
  
  /**
   * Implementation of kpi sampler for OTS.
   * <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 RoadSampler extends Sampler<GtuDataRoad, LaneDataRoad> implements EventListener
  {
  
      /** */
      private static final long serialVersionUID = 20200228L;
  
      /** Simulator. */
      private final OtsSimulatorInterface simulator;
  
      /** Network. */
      private final RoadNetwork network;
  
      /** Sampling interval. */
      private final Duration samplingInterval;
  
      /** Registration of sampling events of each GTU per lane, if interval based. */
      private final Map<String, Map<Lane, SimEventInterface<Duration>>> eventsPerGtu = new LinkedHashMap<>();
  
      /** Set of lanes the sampler knows each GTU to be at. Usually 1, could be 2 during a trajectory transition. */
      private final Map<String, Set<Lane>> activeLanesPerGtu = new LinkedHashMap<>();
  
      /** Set of actively sampled GTUs. */
      private final Set<String> activeGtus = new LinkedHashSet<>();
  
      /**
       * Constructor which uses the operational plan updates of GTU's as sampling interval.
       * @param network the network
       * @throws NullPointerException if the simulator is {@code null}
       */
      public RoadSampler(final RoadNetwork network)
      {
          this(new LinkedHashSet<>(), new LinkedHashSet<>(), network);
      }
  
      /**
       * Constructor which uses the operational plan updates of GTU's as sampling interval.
       * @param extendedDataTypes extended data types
       * @param filterDataTypes filter data types
       * @param network the network
       * @throws NullPointerException if the simulator is {@code null}
       */
      public RoadSampler(final Set<ExtendedDataType<?, ?, ?, ? super GtuDataRoad>> extendedDataTypes,
              final Set<FilterDataType<?, ? super GtuDataRoad>> filterDataTypes, final RoadNetwork network)
      {
          super(extendedDataTypes, filterDataTypes);
          Throw.whenNull(network, "Network may not be null.");
          this.network = network;
          this.simulator = network.getSimulator();
          this.samplingInterval = null;
      }
  
      /**
       * Constructor which uses the given frequency to determine the sampling interval.
       * @param network the network
      * @param frequency sampling frequency
      * @throws NullPointerException if an input is {@code null}
      * @throws IllegalArgumentException if frequency is negative or zero
      */
     public RoadSampler(final RoadNetwork network, final Frequency frequency)
     {
         this(new LinkedHashSet<>(), new LinkedHashSet<>(), network, frequency);
     }
 
     /**
      * Constructor which uses the given frequency to determine the sampling interval.
      * @param extendedDataTypes extended data types
      * @param filterDataTypes filter data types
      * @param network the network
      * @param frequency sampling frequency
      * @throws NullPointerException if an input is {@code null}
      * @throws IllegalArgumentException if frequency is negative or zero
      */
     public RoadSampler(final Set<ExtendedDataType<?, ?, ?, ? super GtuDataRoad>> extendedDataTypes,
             final Set<FilterDataType<?, ? super GtuDataRoad>> filterDataTypes, final RoadNetwork network,
             final Frequency frequency)
     {
         super(extendedDataTypes, filterDataTypes);
         Throw.whenNull(network, "Network may not be null.");
         Throw.whenNull(frequency, "Frequency may not be null.");
         Throw.when(frequency.le(Frequency.ZERO), IllegalArgumentException.class,
                 "Negative or zero sampling frequency is not permitted.");
         this.network = network;
         this.simulator = network.getSimulator();
         this.samplingInterval = new Duration(1.0 / frequency.si, DurationUnit.SI);
     }
 
     @Override
     public final Time now()
     {
         return this.simulator.getSimulatorAbsTime();
     }
 
     @Override
     public final void scheduleStartRecording(final Time time, final LaneDataRoad lane)
     {
         try
         {
             this.simulator.scheduleEventAbsTime(time, this, "startRecording", new Object[] {lane});
         }
         catch (SimRuntimeException exception)
         {
             throw new RuntimeException("Cannot start recording.", exception);
         }
     }
 
     @Override
     public final void scheduleStopRecording(final Time time, final LaneDataRoad lane)
     {
         try
         {
             this.simulator.scheduleEventAbsTime(time, this, "stopRecording", new Object[] {lane});
         }
         catch (SimRuntimeException exception)
         {
             throw new RuntimeException("Cannot stop recording.", exception);
         }
     }
 
     @Override
     public final void initRecording(final LaneDataRoad lane)
     {
         Lane roadLane = lane.getLane();
         // @docs/02-model-structure/djutils.md#event-producers-and-listeners
         roadLane.addListener(this, Lane.GTU_ADD_EVENT, ReferenceType.WEAK);
         roadLane.addListener(this, Lane.GTU_REMOVE_EVENT, ReferenceType.WEAK);
         // @end
         int count = 1;
         for (LaneBasedGtu gtu : roadLane.getGtuList())
         {
             try
             {
                 // Payload: Object[] {String gtuId, Lane source}
                 notify(new TimedEvent<>(Lane.GTU_ADD_EVENT,
                         new Object[] {gtu.getId(), count, roadLane.getId(), roadLane.getLink().getId()},
                         gtu.getSimulator().getSimulatorTime()));
                 count++;
             }
             catch (Exception exception)
             {
                 throw new RuntimeException("Position cannot be obtained for GTU that is registered on a lane", exception);
             }
         }
     }
 
     @Override
     public final void finalizeRecording(final LaneDataRoad lane)
     {
         Lane roadLane = lane.getLane();
         roadLane.removeListener(this, Lane.GTU_ADD_EVENT);
         roadLane.removeListener(this, Lane.GTU_REMOVE_EVENT);
     }
 
     @Override
     // @docs/02-model-structure/djutils.md#event-producers-and-listeners (if-structure + add/removeListener(...))
     public final void notify(final Event event) throws RemoteException
     {
         if (event.getType().equals(LaneBasedGtu.LANEBASED_MOVE_EVENT))
         {
             // Payload: [String gtuId, PositionVector currentPosition, Direction currentDirection, Speed speed, Acceleration
             // acceleration, TurnIndicatorStatus turnIndicatorStatus, Length odometer, Link id of referenceLane, Lane id of
             // referenceLane, Length positionOnReferenceLane]
             Object[] payload = (Object[]) event.getContent();
             CrossSectionLink link = (CrossSectionLink) this.network.getLink(payload[7].toString());
             Lane lane = (Lane) link.getCrossSectionElement(payload[8].toString());
             LaneBasedGtu gtu = (LaneBasedGtu) this.network.getGTU(payload[0].toString());
             LaneDataRoad laneData = new LaneDataRoad(lane);
 
             if (!this.activeGtus.contains(gtu.getId()) && this.getSamplerData().contains(laneData))
             {
                 // GTU add was skipped during add event due to an improper phase of initialization, do here instead
                 addGtu(laneData, new GtuDataRoad(gtu));
                 this.activeGtus.add(gtu.getId());
             }
             snapshot(laneData, (Length) payload[9], (Speed) payload[3], (Acceleration) payload[4], now(), new GtuDataRoad(gtu));
         }
         else if (event.getType().equals(Lane.GTU_ADD_EVENT))
         {
             // Payload: Object[] {String gtuId, int count_after_addition, String laneId, String linkId}
             Object[] payload = (Object[]) event.getContent();
             Lane lane = (Lane) ((CrossSectionLink) this.network.getLink((String) payload[3]))
                     .getCrossSectionElement((String) payload[2]);
             LaneDataRoad laneData = new LaneDataRoad(lane);
             if (!getSamplerData().contains(laneData))
             {
                 return; // we are not sampling this Lane
             }
             LaneBasedGtu gtu = (LaneBasedGtu) this.network.getGTU((String) payload[0]);
 
             // Skip add when first encountering this GTU, it is in an improper phase of initialization.
             // If interval-based, a GTU is also not in the active list in the moment of an instantaneous lane-change.
             boolean active = this.activeGtus.contains(gtu.getId());
             if (active)
             {
                 Length position = Try.assign(() -> gtu.position(lane, RelativePosition.REFERENCE_POSITION),
                         "Could not determine position.");
                 Speed speed = gtu.getSpeed();
                 Acceleration acceleration = gtu.getAcceleration();
                 addGtuWithSnapshot(laneData, position, speed, acceleration, now(), new GtuDataRoad(gtu));
             }
 
             if (isIntervalBased())
             {
                 double currentTime = now().getSI();
                 double next = Math.ceil(currentTime / this.samplingInterval.getSI()) * this.samplingInterval.getSI();
                 if (next > currentTime)
                 {
                     // add sample at current time, then synchronize in interval
                     notifySample(gtu, lane, false);
                     scheduleSamplingInterval(gtu, lane, Duration.instantiateSI(next - currentTime));
                 }
                 else
                 {
                     // already synchronous
                     notifySample(gtu, lane, true);
                 }
             }
             else
             {
                 this.activeLanesPerGtu.computeIfAbsent(gtu.getId(), (key) -> new LinkedHashSet<>()).add(lane);
                 gtu.addListener(this, LaneBasedGtu.LANEBASED_MOVE_EVENT, ReferenceType.WEAK);
             }
         }
         else if (event.getType().equals(Lane.GTU_REMOVE_EVENT))
         {
             // Payload: Object[] {String gtuId, LaneBasedGtu gtu, int count_after_removal, Length position, String laneId,
             // String linkId}
             Object[] payload = (Object[]) event.getContent();
             Lane lane = (Lane) ((CrossSectionLink) this.network.getLink((String) payload[5]))
                     .getCrossSectionElement((String) payload[4]);
             LaneDataRoad laneData = new LaneDataRoad(lane);
             LaneBasedGtu gtu = (LaneBasedGtu) payload[1];
             Length position = (Length) payload[3];
             Speed speed = gtu.getSpeed();
             Acceleration acceleration = gtu.getAcceleration();
 
             removeGtuWithSnapshot(laneData, position, speed, acceleration, now(), new GtuDataRoad(gtu));
 
             if (isIntervalBased())
             {
                 Map<Lane, SimEventInterface<Duration>> events = this.eventsPerGtu.get(gtu.getId());
                 SimEventInterface<Duration> e = events.remove(lane);
                 if (e != null)
                 {
                     this.simulator.cancelEvent(e);
                 }
                 if (events.isEmpty())
                 {
                     this.eventsPerGtu.remove(gtu.getId());
                     this.activeGtus.remove(gtu.getId());
                 }
             }
             else
             {
                 this.activeLanesPerGtu.get(gtu.getId()).remove(lane);
                 if (this.activeLanesPerGtu.get(gtu.getId()).isEmpty())
                 {
                     this.activeLanesPerGtu.remove(gtu.getId());
                     gtu.removeListener(this, LaneBasedGtu.LANEBASED_MOVE_EVENT);
                     this.activeGtus.remove(gtu.getId());
                 }
             }
         }
     }
 
     /**
      * @return whether sampling is interval based
      */
     private boolean isIntervalBased()
     {
         return this.samplingInterval != null;
     }
 
     /**
      * Schedules a sampling event for the given gtu on the given lane for the sampling interval from the current time.
      * @param gtu gtu to sample
      * @param lane lane where the gtu is at
      * @param inTime relative time to schedule
      */
     private void scheduleSamplingInterval(final LaneBasedGtu gtu, final Lane lane, final Duration inTime)
     {
         SimEventInterface<Duration> simEvent;
         try
         {
             simEvent = this.simulator.scheduleEventRel(inTime, this, "notifySample", new Object[] {gtu, lane, true});
         }
         catch (SimRuntimeException exception)
         {
             // should not happen with getSimulatorTime.add()
             throw new RuntimeException("Scheduling sampling in the past.", exception);
         }
         this.eventsPerGtu.computeIfAbsent(gtu.getId(), (key) -> new LinkedHashMap<>()).put(lane, simEvent);
     }
 
     /**
      * Samples a gtu and schedules the next sampling event. This is used for interval-based sampling.
      * @param gtu gtu to sample
      * @param lane lane direction where the gtu is at
      * @param scheduleNext whether to schedule the next event
      */
     public final void notifySample(final LaneBasedGtu gtu, final Lane lane, final boolean scheduleNext)
     {
         LaneDataRoad laneData = new LaneDataRoad(lane);
         try
         {
             Length position = gtu.position(lane, RelativePosition.REFERENCE_POSITION);
             if (this.activeGtus.contains(gtu.getId()))
             {
                 // already recording this GTU, just trigger a record through a move
                 snapshot(laneData, position, gtu.getSpeed(), gtu.getAcceleration(), now(), new GtuDataRoad(gtu));
             }
             else
             {
                 // first time encountering this GTU so add, which also triggers a record through a move
                 addGtuWithSnapshot(laneData, position, gtu.getSpeed(), gtu.getAcceleration(), now(), new GtuDataRoad(gtu));
                 this.activeGtus.add(gtu.getId());
             }
         }
         catch (GtuException exception)
         {
             throw new RuntimeException("Requesting position on lane, but the GTU is not on the lane.", exception);
         }
         if (scheduleNext)
         {
             scheduleSamplingInterval(gtu, lane, this.samplingInterval);
         }
     }
 
     @Override
     public final int hashCode()
     {
         final int prime = 31;
         int result = super.hashCode();
         result = prime * result + ((this.eventsPerGtu == null) ? 0 : this.eventsPerGtu.hashCode());
         result = prime * result + ((this.samplingInterval == null) ? 0 : this.samplingInterval.hashCode());
         result = prime * result + ((this.simulator == null) ? 0 : this.simulator.hashCode());
         return result;
     }
 
     @Override
     public final boolean equals(final Object obj)
     {
         if (this == obj)
         {
             return true;
         }
         if (!super.equals(obj))
         {
             return false;
         }
         if (getClass() != obj.getClass())
         {
             return false;
         }
         RoadSampler other = (RoadSampler) obj;
         if (this.eventsPerGtu == null)
         {
             if (other.eventsPerGtu != null)
             {
                 return false;
             }
         }
         else if (!this.eventsPerGtu.equals(other.eventsPerGtu))
         {
             return false;
         }
         if (this.samplingInterval == null)
         {
             if (other.samplingInterval != null)
             {
                 return false;
             }
         }
         else if (!this.samplingInterval.equals(other.samplingInterval))
         {
             return false;
         }
         if (this.simulator == null)
         {
             if (other.simulator != null)
             {
                 return false;
             }
         }
         else if (!this.simulator.equals(other.simulator))
         {
             return false;
         }
         return true;
     }
 
     @Override
     public final String toString()
     {
         return "RoadSampler [samplingInterval=" + this.samplingInterval + "]";
         // do not use "this.eventPerGtu", it creates circular toString and hence stack overflow
     }
 
     /**
      * Returns a factory to create a sampler.
      * @param network network
      * @return factory to create a sampler
      */
     public static Factory build(final RoadNetwork network)
     {
         return new Factory(network);
     }
 
     /** Factory for {@code RoadSampler}. */
     public static final class Factory
     {
 
         /** Simulator. */
         private final RoadNetwork network;
 
         /** Registration of included extended data types. */
         private final Set<ExtendedDataType<?, ?, ?, ? super GtuDataRoad>> extendedDataTypes = new LinkedHashSet<>();
 
         /** Set of registered filter data types. */
         private final Set<FilterDataType<?, ? super GtuDataRoad>> filterDataTypes = new LinkedHashSet<>();
 
         /** Frequency. */
         private Frequency freq;
 
         /**
          * Constructor.
          * @param network network
          */
         Factory(final RoadNetwork network)
         {
             this.network = network;
         }
 
         /**
          * Register extended data type.
          * @param extendedDataType extended data type
          * @return this factory
          */
         public Factory registerExtendedDataType(final ExtendedDataType<?, ?, ?, ? super GtuDataRoad> extendedDataType)
         {
             Throw.whenNull(extendedDataType, "Extended data type may not be null.");
             this.extendedDataTypes.add(extendedDataType);
             return this;
         }
 
         /**
          * Register filter data type.
          * @param filterDataType filter data type
          * @return this factory
          */
         public Factory registerFilterDataType(final FilterDataType<?, ? super GtuDataRoad> filterDataType)
         {
             Throw.whenNull(filterDataType, "Filter data type may not be null.");
             this.filterDataTypes.add(filterDataType);
             return this;
         }
 
         /**
          * Sets the frequency. If no frequency is set, a sampler is created that records on move events of GTU's.
          * @param frequency frequency
          * @return this factory
          */
         public Factory setFrequency(final Frequency frequency)
         {
             this.freq = frequency;
             return this;
         }
 
         /**
          * Create sampler.
          * @return sampler
          */
         public RoadSampler create()
         {
             return this.freq == null ? new RoadSampler(this.extendedDataTypes, this.filterDataTypes, this.network)
                     : new RoadSampler(this.extendedDataTypes, this.filterDataTypes, this.network, this.freq);
         }
 
     }
 
 }