package org.opentrafficsim.road.gtu.generator;
   
   import java.util.LinkedHashMap;
   import java.util.Map;
   import java.util.PriorityQueue;
   import java.util.Queue;
   import java.util.SortedMap;
   import java.util.TreeMap;
   
  import javax.naming.NamingException;
  
  import org.djunits.value.vdouble.scalar.Duration;
  import org.djunits.value.vdouble.scalar.Frequency;
  import org.djunits.value.vdouble.vector.DurationVector;
  import org.djunits.value.vdouble.vector.FrequencyVector;
  import org.djutils.exceptions.Throw;
  import org.djutils.exceptions.Try;
  import org.djutils.math.means.ArithmeticMean;
  import org.opentrafficsim.base.geometry.OtsGeometryException;
  import org.opentrafficsim.base.logger.Logger;
  import org.opentrafficsim.base.parameters.ParameterException;
  import org.opentrafficsim.core.dsol.OtsSimulatorInterface;
  import org.opentrafficsim.core.gtu.GtuException;
  import org.opentrafficsim.core.gtu.GtuType;
  import org.opentrafficsim.core.network.NetworkException;
  import org.opentrafficsim.core.network.Node;
  import org.opentrafficsim.road.gtu.generator.characteristics.LaneBasedGtuCharacteristicsGenerator;
  import org.opentrafficsim.road.gtu.generator.characteristics.LaneBasedGtuCharacteristicsGeneratorOd;
  import org.opentrafficsim.road.network.lane.Lane;
  import org.opentrafficsim.road.od.Category;
  import org.opentrafficsim.road.od.Interpolation;
  
  import nl.tudelft.simulation.dsol.SimRuntimeException;
  import nl.tudelft.simulation.jstats.streams.StreamInterface;
  
  /**
   * Connects with a lane-based GTU generator to disable it over some time and generate a platoon instead. Platoons are added as:
   * {@code Platoons.ofCategory(...).addPlatoon(...).addGtu(...).addGtu(...).addPlatoon(...).addGtu(...).addGtu(...).start();}.
   * Method {@code addGtu(...)} may only determine a generation time if other info is set by {@code fixInfo(...)}.<br>
   * <br>
   * This class may be used with a {@code LaneBasedGtuCharacteristicsGenerator} or {@code GtuCharacteristicsGeneratorOD}. Use
   * {@code ofGtuType()} or {@code ofCategory()} respectively.
   * <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>
   * @param <T> type of demand category, typically a Category in an OdMatrix or a GtuType
   */
  public abstract class Platoons<T>
  {
  
      /** GTU generator to disable. */
      private LaneBasedGtuGenerator gen;
  
      /** Simulator. */
      private final OtsSimulatorInterface simulator;
  
      /** Position to generate the GTU's at. */
      private final Lane position;
  
      /** Queue of GTU information to generate GTU's with. */
      private final Queue<PlatoonGtu<T>> queue = new PriorityQueue<>();
  
      /** Map of platoon start and end times. */
      private final SortedMap<Duration, Duration> periods = new TreeMap<>();
  
      /** Start time of current platoon. */
      private Duration startTime;
  
      /** End time of current platoon. */
      private Duration endTime;
  
      /** Origin to use on added GTU. */
      private Node fixedOrigin;
  
      /** Destination to use on added GTU. */
      private Node fixedDestination;
  
      /** Category to use on added GTU. */
      private T fixedCategory;
  
      /** Number of GTUs that will be generated. */
      private Map<T, Integer> numberOfGtus = new LinkedHashMap<>();
  
      /** Whether the Platoons was started, after which nothing may be added. */
      private boolean started = false;
  
      /**
       * Constructor.
       * @param simulator simulator
       * @param position position
       */
      private Platoons(final OtsSimulatorInterface simulator, final Lane position)
      {
          this.simulator = simulator;
          this.position = position;
     }
 
     /**
      * Creates a {@code Platoon&lt;Category&gt;} instance for platoons.
      * @param characteristics characteristics generator
      * @param simulator simulator
      * @param stream random number stream
      * @param position position
      * @return platoons based on OD
      */
     public static Platoons<Category> ofCategory(final LaneBasedGtuCharacteristicsGeneratorOd characteristics,
             final OtsSimulatorInterface simulator, final StreamInterface stream, final Lane position)
     {
         return new Platoons<Category>(simulator, position)
         {
             /** Characteristics generator OD based. */
             private final LaneBasedGtuCharacteristicsGeneratorOd characteristicsOD = characteristics;
 
             /** Random number stream. */
             private final StreamInterface strm = stream;
 
             @Override
             protected void placeGtu(final PlatoonGtu<Category> platoonGtu) throws SimRuntimeException, NamingException,
                     GtuException, NetworkException, OtsGeometryException, ParameterException
             {
                 getGenerator().queueGtu(this.characteristicsOD.draw(platoonGtu.origin(), platoonGtu.destination(),
                         platoonGtu.category(), this.strm), getPosition());
                 start();
             }
         };
     }
 
     /**
      * Creates a {@code Platoon&lt;GtuType&gt;} instance for platoons.
      * @param characteristics characteristics generator
      * @param simulator simulator
      * @param stream random number stream
      * @param position position
      * @return platoons based on OD
      */
     @SuppressWarnings("synthetic-access")
     public static Platoons<GtuType> ofGtuType(final LaneBasedGtuCharacteristicsGenerator characteristics,
             final OtsSimulatorInterface simulator, final StreamInterface stream, final Lane position)
     {
         return new Platoons<GtuType>(simulator, position)
         {
             /** Characteristics generator. */
             private final LaneBasedGtuCharacteristicsGenerator chrctrstcs = characteristics;
 
             @Override
             protected void placeGtu(final PlatoonGtu<GtuType> platoonGtu) throws SimRuntimeException, NamingException,
                     GtuException, NetworkException, OtsGeometryException, ParameterException
             {
                 // we actually do nothing with the platoonGtu here
                 getGenerator().queueGtu(this.chrctrstcs.draw(), getPosition());
                 start();
             }
         };
     }
 
     /**
      * Add a platoon. The generator is disabled during the provided time frame. Individual GTU's should be added using
      * {@code addGtu}.
      * @param start start time
      * @param end end time
      * @return for method chaining
      * @throws SimRuntimeException on exception
      */
     public Platoons<T> addPlatoon(final Duration start, final Duration end) throws SimRuntimeException
     {
         Throw.when(this.started, IllegalStateException.class, "Cannot add a platoon after the Platoons was started.");
         Throw.whenNull(start, "Start may not be null.");
         Throw.whenNull(end, "End may not be null.");
         this.startTime = start;
         this.endTime = end;
         this.periods.put(start, end);
         return this;
     }
 
     /**
      * Fix all info except time for GTU's added hereafter.
      * @param origin origin
      * @param destination destination
      * @param category category
      * @return for method chaining
      */
     public Platoons<T> fixInfo(final Node origin, final Node destination, final T category)
     {
         this.fixedOrigin = origin;
         this.fixedDestination = destination;
         this.fixedCategory = category;
         return this;
     }
 
     /**
      * Add GTU to the current platoon. Per platoon, GTU may be given in any order. This method uses info set with
      * {@code fixInfo}.
      * @param time time of generation
      * @return for method chaining
      * @throws IllegalStateException if no fixed info was set using {@code fixInfo}
      */
     public Platoons<T> addGtu(final Duration time)
     {
         Throw.when(this.fixedOrigin == null || this.fixedDestination == null || this.fixedCategory == null,
                 IllegalStateException.class, "When using addGtu(Time), used fixInfo(...) before to set other info.");
         return addGtu(time, this.fixedOrigin, this.fixedDestination, this.fixedCategory);
     }
 
     /**
      * Add GTU to the current platoon. Per platoon, GTU may be given in any order.
      * @param time time of generation
      * @param origin origin
      * @param destination destination
      * @param category category
      * @return for method chaining
      * @throws IllegalStateException if no platoon was started or time is outside of the platoon time range
      */
     public Platoons<T> addGtu(final Duration time, final Node origin, final Node destination, final T category)
     {
         Throw.when(this.started, IllegalStateException.class, "Cannot add a GTU after the Platoons was started.");
         Throw.when(this.startTime == null || this.endTime == null, IllegalStateException.class,
                 "First call addPlatoon() before calling addGtu()");
         Throw.when(time.gt(this.endTime) || time.lt(this.startTime), IllegalArgumentException.class,
                 "Time %s is not between %s and %s", time, this.startTime, this.endTime);
         this.queue.add(new PlatoonGtu<>(time, origin, destination, category));
         this.numberOfGtus.put(category, this.numberOfGtus.getOrDefault(category, 0) + 1);
         return this;
     }
 
     /**
      * Sets the generator and starts the events.
      * @param generator GTU generator
      * @throws SimRuntimeException if start of first platoon is in the past
      */
     public void start(final LaneBasedGtuGenerator generator) throws SimRuntimeException
     {
         Throw.when(this.started, IllegalStateException.class, "Cannot start the Platoons, it was already started.");
         this.gen = generator;
         // check platoon overlap
         Duration prevEnd = null;
         for (Map.Entry<Duration, Duration> entry : this.periods.entrySet())
         {
             Duration start = entry.getKey();
             Throw.when(prevEnd != null && start.le(prevEnd), IllegalStateException.class, "Platoons are overlapping.");
             prevEnd = entry.getValue();
             this.gen.disable(start, prevEnd, this.position);
         }
         this.started = true;
         start();
     }
 
     /**
      * Returns the vehicle generator for sub classes.
      * @return vehicle generator for sub classes
      */
     protected LaneBasedGtuGenerator getGenerator()
     {
         return this.gen;
     }
 
     /**
      * Returns the position for sub classes.
      * @return position for sub classes
      */
     protected Lane getPosition()
     {
         return this.position;
     }
 
     /**
      * Starts the events.
      * @throws SimRuntimeException if start of first platoon is in the past
      */
     protected void start() throws SimRuntimeException
     {
         if (!this.queue.isEmpty())
         {
             this.simulator.scheduleEventAbs(this.queue.peek().time(),
                     () -> Try.execute(() -> placeGtu(this.queue.poll()), "Exception while placing platoon GTU."));
         }
     }
 
     /**
      * Creates a demand vector in which the platoon demand has been compensated from the input demand vector. Only demand
      * pertaining to the location where the platoons are generated should be compensated.
      * @param category category
      * @param demand demand vector
      * @param time time vector
      * @param interpolation interpolation
      * @return demand vector in which the platoon demand has been compensated from the input demand vector
      */
     public FrequencyVector compensate(final T category, final FrequencyVector demand, final DurationVector time,
             final Interpolation interpolation)
     {
         Throw.whenNull(category, "Category may not be null.");
         Throw.whenNull(demand, "Demand may not be null.");
         Throw.whenNull(time, "Time may not be null.");
         Throw.whenNull(interpolation, "Interpolation may not be null.");
         Throw.when(demand.size() != time.size(), IllegalArgumentException.class, "Demand and time have unequal length.");
         ArithmeticMean<Double, Double> weightedSumLost = new ArithmeticMean<>();
         for (Map.Entry<Duration, Duration> entry : this.periods.entrySet())
         {
             Duration start = entry.getKey();
             Duration end = entry.getValue();
             for (int i = 0; i < demand.size() - 1; i++)
             {
                 Duration s = Duration.max(start, time.get(i));
                 Duration e = Duration.min(end, time.get(i + 1));
                 if (s.lt(e))
                 {
                     Frequency fStart = interpolation.interpolateVector(s, demand, time, true);
                     // TODO: end time of platoon may be in next demand period, which makes the demand non-linear
                     Frequency fEnd = interpolation.interpolateVector(e, demand, time, false);
                     weightedSumLost.add((fStart.si + fEnd.si) / 2, e.si - s.si);
                 }
             }
         }
         ArithmeticMean<Double, Double> weightedSumTotal = new ArithmeticMean<>();
         for (int i = 0; i < demand.size() - 1; i++)
         {
             Frequency fStart = interpolation.interpolateVector(time.get(i), demand, time, true);
             Frequency fEnd = interpolation.interpolateVector(time.get(i + 1), demand, time, false);
             weightedSumTotal.add((fStart.si + fEnd.si) / 2, time.getSI(i + 1) - time.getSI(i));
 
         }
         // calculate factor
         double lost = weightedSumLost.getSum();
         double total = weightedSumTotal.getSum();
         int platooning = this.numberOfGtus.getOrDefault(category, 0);
         double factor = (total - platooning) / (total - lost);
         if (factor < 0.0)
         {
             Logger.ots().warn("Reducing demand of {} by {}, demand is set to 0.", total, total - factor * total);
             factor = 0.0;
         }
         // create and return factor copy
         double[] array = new double[demand.size()];
         for (int i = 0; i < array.length - 1; i++)
         {
             array[i] = demand.getInUnit(i) * factor;
         }
         return new FrequencyVector(array, demand.getDisplayUnit());
     }
 
     /**
      * Places the next platoon GTU and schedules the next one.
      * @param platoonGtu info of GTU to generate
      * @throws SimRuntimeException on exception
      * @throws NamingException on exception
      * @throws GtuException on exception
      * @throws NetworkException on exception
      * @throws OtsGeometryException on exception
      * @throws ParameterException on exception
      */
     protected abstract void placeGtu(PlatoonGtu<T> platoonGtu) throws SimRuntimeException, NamingException, GtuException,
             NetworkException, OtsGeometryException, ParameterException;
 
     /**
      * Class containing info of a GTU to generate.
      * <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>
      * @param time time to generate
      * @param origin origin
      * @param destination destination
      * @param category category
      * @param <K> type of demand category, typically a Category in an OdMatrix or a GtuType
      */
     private record PlatoonGtu<K>(Duration time, Node origin, Node destination, K category) implements Comparable<PlatoonGtu<K>>
     {
         @Override
         public int compareTo(final PlatoonGtu<K> o)
         {
             if (o == null)
             {
                 return 1;
             }
             return this.time.compareTo(o.time);
         }
     }
 }