package org.opentrafficsim.road.network.lane.conflict;
   
   import java.util.ArrayList;
   import java.util.Iterator;
   import java.util.LinkedHashMap;
   import java.util.List;
   import java.util.Map;
   import java.util.Set;
   import java.util.SortedSet;
  import java.util.TreeSet;
  import java.util.concurrent.Executors;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.djunits.value.vdouble.scalar.Length;
  import org.djutils.exceptions.Throw;
  import org.djutils.immutablecollections.ImmutableMap;
  import org.djutils.logger.CategoryLogger;
  import org.opentrafficsim.core.definitions.DefaultsNl;
  import org.opentrafficsim.core.dsol.OtsSimulatorInterface;
  import org.opentrafficsim.core.geometry.OtsGeometryException;
  import org.opentrafficsim.core.geometry.OtsLine3d;
  import org.opentrafficsim.core.geometry.OtsPoint3d;
  import org.opentrafficsim.core.network.Link;
  import org.opentrafficsim.core.network.NetworkException;
  import org.opentrafficsim.road.network.RoadNetwork;
  import org.opentrafficsim.road.network.lane.CrossSectionElement;
  import org.opentrafficsim.road.network.lane.CrossSectionLink;
  import org.opentrafficsim.road.network.lane.Lane;
  import org.pmw.tinylog.Level;
  
  /**
   * <p>
   * Copyright (c) 2013-2023 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://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
   * @author <a href="https://dittlab.tudelft.nl">Wouter Schakel</a>
   */
  // TODO use z-coordinate for intersections of lines
  public final class ConflictBuilderParallel
  {
  
      /** Default width generator for conflicts which uses 80% of the lane width. */
      public static final WidthGenerator DEFAULT_WIDTH_GENERATOR = new RelativeWidthGenerator(0.8);
  
      private static AtomicInteger numberMergeConflicts = new AtomicInteger(0);
  
      private static AtomicInteger numberSplitConflicts = new AtomicInteger(0);
  
      private static AtomicInteger numberCrossConflicts = new AtomicInteger(0);
  
      /**
       * Empty constructor.
       */
      private ConflictBuilderParallel()
      {
          //
      }
  
      /**
       * Build conflicts on network.
       * @param network RoadNetwork; network
       * @param simulator OtsSimulatorInterface; simulator
       * @param widthGenerator WidthGenerator; width generator
       * @throws OtsGeometryException in case of geometry exception
       */
      public static void buildConflicts(final RoadNetwork network, final OtsSimulatorInterface simulator,
              final WidthGenerator widthGenerator) throws OtsGeometryException
      {
          buildConflicts(network, simulator, widthGenerator, new LaneCombinationList(), new LaneCombinationList());
      }
  
      /**
       * Build conflicts on network.
       * @param network RoadNetwork; network
       * @param simulator OtsSimulatorInterface; simulator
       * @param widthGenerator WidthGenerator; width generator
       * @param ignoreList LaneCombinationList; lane combinations to ignore
       * @param permittedList LaneCombinationList; lane combinations that are permitted by traffic control
       * @throws OtsGeometryException in case of geometry exception
       */
      public static void buildConflicts(final RoadNetwork network, final OtsSimulatorInterface simulator,
              final WidthGenerator widthGenerator, final LaneCombinationList ignoreList, final LaneCombinationList permittedList)
              throws OtsGeometryException
      {
          // Create list of lanes
          ImmutableMap<String, Link> links = network.getLinkMap();
          List<Lane> lanes = new ArrayList<>();
          for (String linkId : links.keySet())
          {
              Link link = links.get(linkId);
              if (link instanceof CrossSectionLink)
              {
                  for (CrossSectionElement element : ((CrossSectionLink) link).getCrossSectionElementList())
                  {
                      if (element instanceof Lane)
                      {
                         lanes.add((Lane) element);
                     }
                 }
             }
         }
         buildConflictsParallelBig(lanes, simulator, widthGenerator, ignoreList, permittedList);
     }
 
     /**
      * Build conflicts on list of lanes.
      * @param lanes List&lt;Lane&gt;; lanes
      * @param simulator OtsSimulatorInterface; simulator
      * @param widthGenerator WidthGenerator; width generator
      * @throws OtsGeometryException in case of geometry exception
      */
     public static void buildConflicts(final List<Lane> lanes, final OtsSimulatorInterface simulator,
             final WidthGenerator widthGenerator) throws OtsGeometryException
     {
         buildConflictsParallelBig(lanes, simulator, widthGenerator, new LaneCombinationList(), new LaneCombinationList());
     }
 
     /**
      * Build conflicts on list of lanes. Small jobs for parallelization.
      * @param lanes List&lt;Lane&gt;; list of Lanes
      * @param simulator OtsSimulatorInterface; the simulator
      * @param widthGenerator WidthGenerator; the width generator
      * @param ignoreList LaneCombinationList; lane combinations to ignore
      * @param permittedList LaneCombinationList; lane combinations that are permitted by traffic control
      * @throws OtsGeometryException in case of geometry exception
      */
     public static void buildConflictsParallelSmall(final List<Lane> lanes, final OtsSimulatorInterface simulator,
             final WidthGenerator widthGenerator, final LaneCombinationList ignoreList, final LaneCombinationList permittedList)
             throws OtsGeometryException
     {
         long totalCombinations = ((long) lanes.size()) * ((long) lanes.size() - 1) / 2;
         System.out.println("GENERATING CONFLICTS (SMALL JOBS). " + totalCombinations + " COMBINATIONS");
         CategoryLogger.setAllLogLevel(Level.DEBUG);
         long lastReported = 0;
         Map<Lane, OtsLine3d> leftEdges = new LinkedHashMap<>();
         Map<Lane, OtsLine3d> rightEdges = new LinkedHashMap<>();
 
         // force the envelopes to be built first
         for (Lane lane : lanes)
         {
             lane.getContour().getEnvelope();
         }
 
         // make a threadpool and execute buildConflicts for all records
         int cores = Runtime.getRuntime().availableProcessors();
         System.out.println("USING " + cores + " CORES");
         ThreadPoolExecutor executor = (ThreadPoolExecutor) Executors.newFixedThreadPool(2 * cores);
         AtomicInteger numberOfJobs = new AtomicInteger(0);
         final int maxqueue = 200;
 
         for (int i = 0; i < lanes.size(); i++)
         {
             long combinationsDone = totalCombinations - ((long) (lanes.size() - i)) * ((long) (lanes.size() - i)) / 2;
             if (combinationsDone / 1000000 > lastReported)
             {
                 simulator.getLogger().always()
                         .debug(String.format("generating conflicts at %.2f%%", 100.0 * combinationsDone / totalCombinations));
                 lastReported = combinationsDone / 1000000;
             }
             Lane lane1 = lanes.get(i);
             Set<Lane> down1 = lane1.nextLanes(null);
             Set<Lane> up1 = lane1.prevLanes(null);
 
             for (int j = i + 1; j < lanes.size(); j++)
             {
                 Lane lane2 = lanes.get(j);
                 if (ignoreList.contains(lane1, lane2))
                 {
                     continue;
                 }
                 // Quick contour check, skip if non-overlapping envelopes
                 try
                 {
                     if (!lane1.getContour().intersects(lane2.getContour()))
                     {
                         continue;
                     }
                 }
                 catch (Exception e)
                 {
                     System.err.println("Contour problem - lane1 = [" + lane1.getFullId() + "], lane2 = [" + lane2.getFullId()
                             + "]; skipped");
                     continue;
                 }
 
                 boolean permitted = permittedList.contains(lane1, lane2);
 
                 while (numberOfJobs.get() > maxqueue) // keep max maxqueue jobs in the pool
                 {
                     try
                     {
                         Thread.sleep(0, 10);
                     }
                     catch (InterruptedException exception)
                     {
                         // ignore
                     }
                 }
                 numberOfJobs.incrementAndGet();
                 Set<Lane> down2 = lane2.nextLanes(null);
                 Set<Lane> up2 = lane2.prevLanes(null);
                 ConflictBuilderRecord cbr = new ConflictBuilderRecord(lane1, down1, up1, lane2, down2, up2, permitted,
                         simulator, widthGenerator, leftEdges, rightEdges);
                 executor.execute(new CbrTask(numberOfJobs, cbr));
             }
         }
 
         System.out.println("WAITING FOR LAST " + maxqueue + " JOBS");
         long time = System.currentTimeMillis();
         // wait max 60 sec for last maxqueue jobs
         while (numberOfJobs.get() > 0 && System.currentTimeMillis() - time < 60000)
         {
             try
             {
                 Thread.sleep(10);
             }
             catch (InterruptedException exception)
             {
                 // ignore
             }
         }
 
         executor.shutdown();
         while (!executor.isTerminated())
         {
             try
             {
                 Thread.sleep(1);
             }
             catch (InterruptedException exception)
             {
                 // ignore
             }
         }
 
         System.out.println("MERGE CONFLICTS = " + numberMergeConflicts);
         System.out.println("SPLIT CONFLICTS = " + numberSplitConflicts);
         System.out.println("CROSS CONFLICTS = " + numberCrossConflicts);
 
         CategoryLogger.setAllLogLevel(Level.WARNING);
     }
 
     /**
      * Build conflicts on list of lanes. Parallelize bigger jobs
      * @param lanes List&lt;Lane&gt;; list of Lanes
      * @param simulator OtsSimulatorInterface; the simulator
      * @param widthGenerator WidthGenerator; the width generator
      * @param ignoreList LaneCombinationList; lane combinations to ignore
      * @param permittedList LaneCombinationList; lane combinations that are permitted by traffic control
      * @throws OtsGeometryException in case of geometry exception
      */
     public static void buildConflictsParallelBig(final List<Lane> lanes, final OtsSimulatorInterface simulator,
             final WidthGenerator widthGenerator, final LaneCombinationList ignoreList, final LaneCombinationList permittedList)
             throws OtsGeometryException
     {
         long totalCombinations = ((long) lanes.size()) * ((long) lanes.size() - 1) / 2;
         System.out.println("GENERATING CONFLICTS (BIG JOBS). " + totalCombinations + " COMBINATIONS");
         CategoryLogger.setAllLogLevel(Level.DEBUG);
         long lastReported = 0;
         Map<Lane, OtsLine3d> leftEdges = new LinkedHashMap<>();
         Map<Lane, OtsLine3d> rightEdges = new LinkedHashMap<>();
 
         // force the envelopes to be built first
         for (Lane lane : lanes)
         {
             lane.getContour().getEnvelope();
         }
 
         // make a threadpool and execute buildConflicts for all records
         int cores = Runtime.getRuntime().availableProcessors();
         System.out.println("USING " + cores + " CORES");
         ThreadPoolExecutor executor = (ThreadPoolExecutor) Executors.newFixedThreadPool(2 * cores);
         AtomicInteger numberOfJobs = new AtomicInteger(0);
         final int maxqueue = 200;
 
         for (int i = 0; i < lanes.size(); i++)
         {
             long combinationsDone = totalCombinations - ((long) (lanes.size() - i)) * ((long) (lanes.size() - i)) / 2;
             if (combinationsDone / 1000000 > lastReported)
             {
                 simulator.getLogger().always()
                         .debug(String.format("generating conflicts at %.2f%%", 100.0 * combinationsDone / totalCombinations));
                 lastReported = combinationsDone / 1000000;
             }
             Lane lane1 = lanes.get(i);
             Set<Lane> down1 = lane1.nextLanes(null);
             Set<Lane> up1 = lane1.prevLanes(null);
 
             while (numberOfJobs.get() > maxqueue) // keep max maxqueue jobs in the pool
             {
                 try
                 {
                     Thread.sleep(0, 10);
                 }
                 catch (InterruptedException exception)
                 {
                     // ignore
                 }
             }
             numberOfJobs.incrementAndGet();
             final int starti = i;
 
             // START JOB
 
             executor.execute(new Runnable()
             {
                 @Override
                 public void run()
                 {
                     for (int j = starti + 1; j < lanes.size(); j++)
                     {
                         Lane lane2 = lanes.get(j);
                         if (ignoreList.contains(lane1, lane2))
                         {
                             continue;
                         }
                         // Quick contour check, skip if non-overlapping envelopes
                         try
                         {
                             if (!lane1.getContour().intersects(lane2.getContour()))
                             {
                                 continue;
                             }
                         }
                         catch (Exception e)
                         {
                             System.err.println("Contour problem - lane1 = [" + lane1.getFullId() + "], lane2 = ["
                                     + lane2.getFullId() + "]; skipped");
                             continue;
                         }
 
                         boolean permitted = permittedList.contains(lane1, lane2);
 
                         Set<Lane> down2 = lane2.nextLanes(null);
                         Set<Lane> up2 = lane2.prevLanes(null);
 
                         try
                         {
                             buildConflicts(lane1, down1, up1, lane2, down2, up2, permitted, simulator, widthGenerator,
                                     leftEdges, rightEdges);
                         }
                         catch (NetworkException | OtsGeometryException ne)
                         {
                             simulator.getLogger().always().error(ne, "Conflict build with bad combination of types / rules.");
                         }
                     }
                 }
             });
 
             // END JOB
         }
 
         System.out.println("WAITING FOR LAST " + maxqueue + " JOBS");
         long time = System.currentTimeMillis();
         // wait max 60 sec for last maxqueue jobs
         while (numberOfJobs.get() > 0 && System.currentTimeMillis() - time < 60000)
         {
             try
             {
                 Thread.sleep(10);
             }
             catch (InterruptedException exception)
             {
                 // ignore
             }
         }
 
         executor.shutdown();
         while (!executor.isTerminated())
         {
             try
             {
                 Thread.sleep(1);
             }
             catch (InterruptedException exception)
             {
                 // ignore
             }
         }
 
         System.out.println("MERGE CONFLICTS = " + numberMergeConflicts);
         System.out.println("SPLIT CONFLICTS = " + numberSplitConflicts);
         System.out.println("CROSS CONFLICTS = " + numberCrossConflicts);
 
         CategoryLogger.setAllLogLevel(Level.WARNING);
     }
 
     /** */
     static class CbrTask implements Runnable
     {
         /** */
         final ConflictBuilderRecord cbr;
 
         /** */
         final AtomicInteger nrOfJobs;
 
         /**
          * @param nrOfJobs nr
          * @param cbr the record to execute
          */
         CbrTask(final AtomicInteger nrOfJobs, final ConflictBuilderRecord cbr)
         {
             this.nrOfJobs = nrOfJobs;
             this.cbr = cbr;
         }
 
         @Override
         public void run()
         {
             // System.err.println("conflict #" + this.nr);
             try
             {
                 buildConflicts(this.cbr);
             }
             catch (Exception e)
             {
                 e.printStackTrace();
             }
             this.nrOfJobs.decrementAndGet();
         }
     }
 
     /**
      * Build conflicts for one record.
      * @param cbr the lane record
      */
     static void buildConflicts(final ConflictBuilderRecord cbr)
     {
         // See if conflict needs to be build, and build if so
         try
         {
             buildConflicts(cbr.lane1, cbr.down1, cbr.up1, cbr.lane2, cbr.down2, cbr.up2, cbr.permitted, cbr.simulator,
                     cbr.widthGenerator, cbr.leftEdges, cbr.rightEdges);
         }
         catch (NetworkException | OtsGeometryException ne)
         {
             throw new RuntimeException("Conflict build with bad combination of types / rules.", ne);
         }
     }
 
     /**
      * Build conflict on single lane pair. Connecting lanes are determined.
      * @param lane1 Lane; lane 1
      * @param lane2 Lane; lane 2
      * @param simulator OtsSimulatorInterface; simulator
      * @param widthGenerator WidthGenerator; width generator
      * @throws OtsGeometryException in case of geometry exception
      */
     @SuppressWarnings("checkstyle:parameternumber")
     public static void buildConflicts(final Lane lane1, final Lane lane2, final OtsSimulatorInterface simulator,
             final WidthGenerator widthGenerator) throws OtsGeometryException
     {
         buildConflicts(lane1, lane2, simulator, widthGenerator, false);
     }
 
     /**
      * Build conflict on single lane pair. Connecting lanes are determined.
      * @param lane1 Lane; lane 1
      * @param lane2 Lane; lane 2
      * @param simulator OtsSimulatorInterface; simulator
      * @param widthGenerator WidthGenerator; width generator
      * @param permitted boolean; conflict permitted by traffic control
      * @throws OtsGeometryException in case of geometry exception
      */
     @SuppressWarnings("checkstyle:parameternumber")
     public static void buildConflicts(final Lane lane1, final Lane lane2, final OtsSimulatorInterface simulator,
             final WidthGenerator widthGenerator, final boolean permitted) throws OtsGeometryException
     {
         Set<Lane> down1 = lane1.nextLanes(null);
         Set<Lane> up1 = lane1.prevLanes(null);
         Set<Lane> down2 = lane2.nextLanes(null);
         Set<Lane> up2 = lane2.prevLanes(null);
         try
         {
             buildConflicts(lane1, down1, up1, lane2, down2, up2, permitted, simulator, widthGenerator, new LinkedHashMap<>(),
                     new LinkedHashMap<>());
         }
         catch (NetworkException ne)
         {
             throw new RuntimeException("Conflict build with bad combination of types / rules.", ne);
         }
     }
 
     /**
      * Build conflicts on single lane pair.
      * @param lane1 Lane; lane 1
      * @param down1 Set&lt;Lane&gt;; downstream lanes 1
      * @param up1 Set&lt;Lane&gt;; upstream lanes 1
      * @param lane2 Lane; lane 2
      * @param down2 Set&lt;Lane&gt;; downstream lane 2
      * @param up2 Set&lt;Lane&gt;; upstream lanes 2
      * @param permitted boolean; conflict permitted by traffic control
      * @param simulator OtsSimulatorInterface; simulator
      * @param widthGenerator WidthGenerator; width generator
      * @param leftEdges Map&lt;Lane, OtsLine3d&gt;; cache of left edge lines
      * @param rightEdges Map&lt;Lane, OtsLine3d&gt;; cache of right edge lines
      * @throws OtsGeometryException in case of geometry exception
      * @throws NetworkException if the combination of conflict type and both conflict rules is not correct
      */
     @SuppressWarnings({"checkstyle:parameternumber", "checkstyle:methodlength"})
     static void buildConflicts(final Lane lane1, final Set<Lane> down1, final Set<Lane> up1, final Lane lane2,
             final Set<Lane> down2, final Set<Lane> up2, final boolean permitted, final OtsSimulatorInterface simulator,
             final WidthGenerator widthGenerator, final Map<Lane, OtsLine3d> leftEdges, final Map<Lane, OtsLine3d> rightEdges)
             throws OtsGeometryException, NetworkException
     {
 
         // Quick contour check, skip if not overlapping -- HAS TAKEN PLACE SO NOT REPEATED (expensive)
         // if (!lane1.getContour().intersects(lane2.getContour()))
         // {
         // return;
         // }
 
         // Get left and right lines at specified width
         // TODO: we cache, but the width generator may be different
 
         OtsLine3d left1;
         OtsLine3d right1;
         synchronized (lane1)
         {
             left1 = leftEdges.get(lane1);
             right1 = rightEdges.get(lane1);
             OtsLine3d line1 = lane1.getCenterLine();
             if (null == left1)
             {
                 left1 = line1.offsetLine(widthGenerator.getWidth(lane1, 0.0) / 2, widthGenerator.getWidth(lane1, 1.0) / 2);
                 leftEdges.put(lane1, left1);
             }
             if (null == right1)
             {
                 right1 = line1.offsetLine(-widthGenerator.getWidth(lane1, 0.0) / 2, -widthGenerator.getWidth(lane1, 1.0) / 2);
                 rightEdges.put(lane1, right1);
             }
         }
 
         OtsLine3d left2;
         OtsLine3d right2;
         synchronized (lane2)
         {
             left2 = leftEdges.get(lane2);
             right2 = rightEdges.get(lane2);
             OtsLine3d line2 = lane2.getCenterLine();
             if (null == left2)
             {
                 left2 = line2.offsetLine(widthGenerator.getWidth(lane2, 0.0) / 2, widthGenerator.getWidth(lane2, 1.0) / 2);
                 leftEdges.put(lane2, left2);
             }
             if (null == right2)
             {
                 right2 = line2.offsetLine(-widthGenerator.getWidth(lane2, 0.0) / 2, -widthGenerator.getWidth(lane2, 1.0) / 2);
                 rightEdges.put(lane2, right2);
             }
         }
 
         // Get list of all intersection fractions
         SortedSet<Intersection> intersections = Intersection.getIntersectionList(left1, left2, 0);
         intersections.addAll(Intersection.getIntersectionList(left1, right2, 1));
         intersections.addAll(Intersection.getIntersectionList(right1, left2, 2));
         intersections.addAll(Intersection.getIntersectionList(right1, right2, 3));
 
         // Create merge
         Iterator<Lane> iterator1 = down1.iterator();
         Iterator<Lane> iterator2 = down2.iterator();
         boolean merge = false;
         while (iterator1.hasNext() && !merge)
         {
             Lane next1 = iterator1.next();
             while (iterator2.hasNext() && !merge)
             {
                 Lane next2 = iterator2.next();
                 if (next1.equals(next2))
                 {
                     // Same downstream lane, so a merge
                     double fraction1 = Double.NaN;
                     double fraction2 = Double.NaN;
                     for (Intersection intersection : intersections)
                     {
                         // Only consider left/right and right/left intersections (others may or may not be at the end)
                         if (intersection.getCombo() == 1 || intersection.getCombo() == 2)
                         {
                             fraction1 = intersection.getFraction1();
                             fraction2 = intersection.getFraction2();
                         }
                     }
                     // Remove all intersections beyond this point, these are the result of line starts/ends matching
                     Iterator<Intersection> iterator = intersections.iterator();
                     while (iterator.hasNext())
                     {
                         if (iterator.next().getFraction1() >= fraction1)
                         {
                             iterator.remove();
                         }
                     }
                     if (Double.isNaN(fraction1))
                     {
                         simulator.getLogger().always().warn("Fixing fractions of merge conflict");
                         fraction1 = 0;
                         fraction2 = 0;
                     }
                     // Build conflict
                     buildMergeConflict(lane1, fraction1, lane2, fraction2, simulator, widthGenerator, permitted);
                     // Skip loop for efficiency, and do not create multiple merges in case of multiple same downstream lanes
                     merge = true;
                 }
             }
         }
 
         // Create split
         iterator1 = up1.iterator();
         iterator2 = up2.iterator();
         boolean split = false;
         while (iterator1.hasNext() && !split)
         {
             Lane prev1 = iterator1.next();
             while (iterator2.hasNext() && !split)
             {
                 Lane prev2 = iterator2.next();
                 if (prev1.equals(prev2))
                 {
                     // Same upstream lane, so a split
                     double fraction1 = Double.NaN;
                     double fraction2 = Double.NaN;
                     for (Intersection intersection : intersections)
                     {
                         // Only consider left/right and right/left intersections (others may or may not be at the start)
                         if (intersection.getCombo() == 1 || intersection.getCombo() == 2)
                         {
                             fraction1 = intersection.getFraction1();
                             fraction2 = intersection.getFraction2();
                             break; // Split so first, not last
                         }
                     }
                     // Remove all intersections up to this point, these are the result of line starts/ends matching
                     Iterator<Intersection> iterator = intersections.iterator();
                     while (iterator.hasNext())
                     {
                         if (iterator.next().getFraction1() <= fraction1)
                         {
                             iterator.remove();
                         }
                         else
                         {
                             // May skip further fraction
                             break;
                         }
                     }
                     if (Double.isNaN(fraction1))
                     {
                         simulator.getLogger().always().warn("Fixing fractions of split conflict");
                         fraction1 = 1;
                         fraction2 = 1;
                     }
                     // Build conflict
                     buildSplitConflict(lane1, fraction1, lane2, fraction2, simulator, widthGenerator);
                     // Skip loop for efficiency, and do not create multiple splits in case of multiple same upstream lanes
                     split = true;
                 }
             }
         }
 
         // Create crossings
         if (!lane1.getParentLink().equals(lane2.getParentLink())) // tight inner-curves with dedicated Bezier ignored
         {
             boolean[] crossed = new boolean[4];
             Iterator<Intersection> iterator = intersections.iterator();
             double f1Start = Double.NaN;
             double f2Start = Double.NaN;
             double f2End = Double.NaN;
             while (iterator.hasNext())
             {
                 Intersection intersection = iterator.next();
                 // First fraction found is start of conflict
                 if (Double.isNaN(f1Start))
                 {
                     f1Start = intersection.getFraction1();
                 }
                 f2Start = Double.isNaN(f2Start) ? intersection.getFraction2() : Math.min(f2Start, intersection.getFraction2());
                 f2End = Double.isNaN(f2End) ? intersection.getFraction2() : Math.max(f2End, intersection.getFraction2());
                 // Flip crossed state of intersecting line combination
                 crossed[intersection.getCombo()] = !crossed[intersection.getCombo()];
                 // If all crossed or all not crossed, end of conflict
                 if ((crossed[0] && crossed[1] && crossed[2] && crossed[3])
                         || (!crossed[0] && !crossed[1] && !crossed[2] && !crossed[3]))
                 {
                     if (Double.isNaN(f1Start) || Double.isNaN(f2Start) || Double.isNaN(f2End))
                     {
                         simulator.getLogger().always().warn("NOT YET Fixing fractions of crossing conflict");
                     }
                     buildCrossingConflict(lane1, f1Start, intersection.getFraction1(), lane2, f2Start, f2End, simulator,
                             widthGenerator, permitted);
                     f1Start = Double.NaN;
                     f2Start = Double.NaN;
                     f2End = Double.NaN;
                 }
             }
         }
 
     }
 
     /**
      * Build a merge conflict.
      * @param lane1 Lane; lane 1
      * @param f1start double; start fraction 1
      * @param lane2 Lane; lane 2
      * @param f2start double; start fraction 2
      * @param simulator OtsSimulatorInterface; simulator
      * @param widthGenerator WidthGenerator; width generator
      * @param permitted boolean; conflict permitted by traffic control
      * @throws NetworkException if the combination of conflict type and both conflict rules is not correct
      * @throws OtsGeometryException in case of geometry exception
      */
     @SuppressWarnings("checkstyle:parameternumber")
     private static void buildMergeConflict(final Lane lane1, final double f1start, final Lane lane2, final double f2start,
             final OtsSimulatorInterface simulator, final WidthGenerator widthGenerator, final boolean permitted)
             throws NetworkException, OtsGeometryException
     {
 
         // Determine lane end from direction
         double f1end = 1.0;
         double f2end = 1.0;
 
         // Get locations and length
         Length longitudinalPosition1 = lane1.getLength().times(f1start);
         Length longitudinalPosition2 = lane2.getLength().times(f2start);
         Length length1 = lane1.getLength().times(Math.abs(f1end - f1start));
         Length length2 = lane2.getLength().times(Math.abs(f2end - f2start));
 
         // Get geometries
         OtsLine3d geometry1 = getGeometry(lane1, f1start, f1end, widthGenerator);
         OtsLine3d geometry2 = getGeometry(lane2, f2start, f2end, widthGenerator);
 
         // Determine conflict rule
         ConflictRule conflictRule;
         if (lane1.getParentLink().getPriority().isBusStop() || lane2.getParentLink().getPriority().isBusStop())
         {
             Throw.when(lane1.getParentLink().getPriority().isBusStop() && lane2.getParentLink().getPriority().isBusStop(),
                     IllegalArgumentException.class, "Merge conflict between two links with bus stop priority not supported.");
             // TODO: handle bus priority on the model side
             conflictRule = new BusStopConflictRule(simulator, DefaultsNl.BUS);
         }
         else
         {
             conflictRule = new DefaultConflictRule();
         }
 
         // Make conflict
         Conflict.generateConflictPair(ConflictType.MERGE, conflictRule, permitted, lane1, longitudinalPosition1, length1,
                 geometry1, lane2, longitudinalPosition2, length2, geometry2, simulator);
 
         numberMergeConflicts.incrementAndGet();
     }
 
     /**
      * Build a split conflict.
      * @param lane1 Lane; lane 1
      * @param f1end double; end fraction 1
      * @param lane2 Lane; lane 2
      * @param f2end double; end fraction 2
      * @param simulator OtsSimulatorInterface; simulator
      * @param widthGenerator WidthGenerator; width generator
      * @throws NetworkException if the combination of conflict type and both conflict rules is not correct
      * @throws OtsGeometryException in case of geometry exception
      */
     @SuppressWarnings("checkstyle:parameternumber")
     private static void buildSplitConflict(final Lane lane1, final double f1end, final Lane lane2, final double f2end,
             final OtsSimulatorInterface simulator, final WidthGenerator widthGenerator)
             throws NetworkException, OtsGeometryException
     {
 
         // Determine lane start from direction
         double f1start = 0.0;
         double f2start = 0.0;
 
         // Get locations and length
         Length longitudinalPosition1 = lane1.getLength().times(f1start);
         Length longitudinalPosition2 = lane2.getLength().times(f2start);
         Length length1 = lane1.getLength().times(Math.abs(f1end - f1start));
         Length length2 = lane2.getLength().times(Math.abs(f2end - f2start));
 
         // Get geometries
         OtsLine3d geometry1 = getGeometry(lane1, f1start, f1end, widthGenerator);
         OtsLine3d geometry2 = getGeometry(lane2, f2start, f2end, widthGenerator);
 
         // Make conflict
         Conflict.generateConflictPair(ConflictType.SPLIT, new SplitConflictRule(), false, lane1, longitudinalPosition1, length1,
                 geometry1, lane2, longitudinalPosition2, length2, geometry2, simulator);
 
         numberSplitConflicts.incrementAndGet();
     }
 
     /**
      * Build a crossing conflict.
      * @param lane1 Lane; lane 1
      * @param f1start double; start fraction 1
      * @param f1end double; end fraction 1
      * @param lane2 Lane; lane 2
      * @param f2start double; start fraction 2
      * @param f2end double; end fraction 2
      * @param simulator OtsSimulatorInterface; simulator
      * @param widthGenerator WidthGenerator; width generator
      * @param permitted boolean; conflict permitted by traffic control
      * @throws NetworkException if the combination of conflict type and both conflict rules is not correct
      * @throws OtsGeometryException in case of geometry exception
      */
     @SuppressWarnings("checkstyle:parameternumber")
     private static void buildCrossingConflict(final Lane lane1, final double f1start, final double f1end, final Lane lane2,
             final double f2start, final double f2end, final OtsSimulatorInterface simulator,
             final WidthGenerator widthGenerator, final boolean permitted) throws NetworkException, OtsGeometryException
     {
 
         // Fractions may be in opposite direction, for the start location this needs to be correct
         // Note: for geometry (real order, not considering direction) and length (absolute value) this does not matter
         double f1startDirected;
         double f2startDirected;
         if (f1end < f1start)
         {
             f1startDirected = f1end;
         }
         else
         {
             f1startDirected = f1start;
         }
         if (f2end < f2start)
         {
             f2startDirected = f2end;
         }
         else
         {
             f2startDirected = f2start;
         }
 
         // Get locations and length
         Length longitudinalPosition1 = lane1.getLength().times(f1startDirected);
         Length longitudinalPosition2 = lane2.getLength().times(f2startDirected);
         Length length1 = lane1.getLength().times(Math.abs(f1end - f1start));
         Length length2 = lane2.getLength().times(Math.abs(f2end - f2start));
 
         // Get geometries
         OtsLine3d geometry1 = getGeometry(lane1, f1start, f1end, widthGenerator);
         OtsLine3d geometry2 = getGeometry(lane2, f2start, f2end, widthGenerator);
 
         // Determine conflict rule
         ConflictRule conflictRule;
         if (lane1.getParentLink().getPriority().isBusStop() || lane2.getParentLink().getPriority().isBusStop())
         {
             Throw.when(lane1.getParentLink().getPriority().isBusStop() && lane2.getParentLink().getPriority().isBusStop(),
                     IllegalArgumentException.class, "Merge conflict between two links with bus stop priority not supported.");
             // TODO: handle bus priority on the model side
             conflictRule = new BusStopConflictRule(simulator, DefaultsNl.BUS);
         }
         else
         {
             conflictRule = new DefaultConflictRule();
         }
 
         // Make conflict
         Conflict.generateConflictPair(ConflictType.CROSSING, conflictRule, permitted, lane1, longitudinalPosition1, length1,
                 geometry1, lane2, longitudinalPosition2, length2, geometry2, simulator);
 
         numberCrossConflicts.incrementAndGet();
     }
 
     /**
      * Creates geometry for conflict.
      * @param lane Lane; lane
      * @param fStart double; longitudinal fraction of start
      * @param fEnd double; longitudinal fraction of end
      * @param widthGenerator WidthGenerator; width generator
      * @return geometry for conflict
      * @throws OtsGeometryException in case of geometry exception
      */
     private static OtsLine3d getGeometry(final Lane lane, final double fStart, final double fEnd,
             final WidthGenerator widthGenerator) throws OtsGeometryException
     {
         // extractFractional needs ordered fractions, irrespective of driving direction
         double f1;
         double f2;
         if (fEnd > fStart)
         {
             f1 = fStart;
             f2 = fEnd;
         }
         else
         {
             f1 = fEnd;
             f2 = fStart;
         }
         OtsLine3d centerLine = lane.getCenterLine().extractFractional(f1, f2);
         OtsLine3d left = centerLine.offsetLine(widthGenerator.getWidth(lane, f1) / 2, widthGenerator.getWidth(lane, f2) / 2);
         OtsLine3d right =
                 centerLine.offsetLine(-widthGenerator.getWidth(lane, f1) / 2, -widthGenerator.getWidth(lane, f2) / 2).reverse();
         OtsPoint3d[] points = new OtsPoint3d[left.size() + right.size()];
         System.arraycopy(left.getPoints(), 0, points, 0, left.size());
         System.arraycopy(right.getPoints(), 0, points, left.size(), right.size());
         return new OtsLine3d(points);
     }
 
     /**
      * Intersection holds two fractions where two lines have crossed. There is also a combo to identify which lines have been
      * used to find the intersection.
      * <p>
      * Copyright (c) 2013-2023 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://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
      * @author <a href="https://dittlab.tudelft.nl">Wouter Schakel</a>
      */
     private static class Intersection implements Comparable<Intersection>
     {
 
         /** Fraction on lane 1. */
         private final double fraction1;
 
         /** Fraction on lane 2. */
         private final double fraction2;
 
         /** Edge combination number. */
         private final int combo;
 
         /**
          * @param fraction1 double; fraction on lane 1
          * @param fraction2 double; fraction on lane 1
          * @param combo int; edge combination number
          */
         Intersection(final double fraction1, final double fraction2, final int combo)
         {
             this.fraction1 = fraction1;
             this.fraction2 = fraction2;
             this.combo = combo;
         }
 
         /**
          * @return fraction1.
          */
         public final double getFraction1()
         {
             return this.fraction1;
         }
 
         /**
          * @return fraction2.
          */
         public final double getFraction2()
         {
             return this.fraction2;
         }
 
         /**
          * @return combo.
          */
         public final int getCombo()
         {
             return this.combo;
         }
 
         /** {@inheritDoc} */
         @Override
         public int compareTo(final Intersection o)
         {
             int out = Double.compare(this.fraction1, o.fraction1);
             if (out != 0)
             {
                 return out;
             }
             out = Double.compare(this.fraction2, o.fraction2);
             if (out != 0)
             {
                 return out;
             }
             return Integer.compare(this.combo, o.combo);
         }
 
         /** {@inheritDoc} */
         @Override
         public int hashCode()
         {
             final int prime = 31;
             int result = 1;
             result = prime * result + this.combo;
             long temp;
             temp = Double.doubleToLongBits(this.fraction1);
             result = prime * result + (int) (temp ^ (temp >>> 32));
             temp = Double.doubleToLongBits(this.fraction2);
             result = prime * result + (int) (temp ^ (temp >>> 32));
             return result;
         }
 
         /** {@inheritDoc} */
         @Override
         public boolean equals(final Object obj)
         {
             if (this == obj)
             {
                 return true;
             }
             if (obj == null)
             {
                 return false;
             }
             if (getClass() != obj.getClass())
             {
                 return false;
             }
             Intersection other = (Intersection) obj;
             if (this.combo != other.combo)
             {
                 return false;
             }
             if (Double.doubleToLongBits(this.fraction1) != Double.doubleToLongBits(other.fraction1))
             {
                 return false;
             }
             if (Double.doubleToLongBits(this.fraction2) != Double.doubleToLongBits(other.fraction2))
             {
                 return false;
             }
             return true;
         }
 
         /**
          * Returns a set of intersections, sorted by the fraction on line 1.
          * @param line1 OtsLine3d; line 1
          * @param line2 OtsLine3d; line 2
          * @param combo int; edge combination number
          * @return set of intersections, sorted by the fraction on line 1
          * @throws OtsGeometryException in case of geometry exception
          */
         public static SortedSet<Intersection> getIntersectionList(final OtsLine3d line1, final OtsLine3d line2, final int combo)
                 throws OtsGeometryException
         {
             SortedSet<Intersection> out = new TreeSet<>();
             // if (!line1.getBounds().intersect(line2.getBounds()))
             // {
             // return out;
             // }
             double cumul1 = 0.0;
             OtsPoint3d start1 = null;
             OtsPoint3d end1 = line1.get(0);
             for (int i = 0; i < line1.size() - 1; i++)
             {
                 start1 = end1;
                 end1 = line1.get(i + 1);
 
                 double cumul2 = 0.0;
                 OtsPoint3d start2 = null;
                 OtsPoint3d end2 = line2.get(0);
 
                 for (int j = 0; j < line2.size() - 1; j++)
                 {
                     start2 = end2;
                     end2 = line2.get(j + 1);
 
                     OtsPoint3d p = OtsPoint3d.intersectionOfLineSegments(start1, end1, start2, end2);
                     if (p != null)
                     {
                         // Segments intersect
                         double dx = p.x - start1.x;
                         double dy = p.y - start1.y;
                         double length1 = cumul1 + Math.sqrt(dx * dx + dy * dy);
                         dx = p.x - start2.x;
                         dy = p.y - start2.y;
                         double length2 = cumul2 + Math.sqrt(dx * dx + dy * dy);
                         out.add(new Intersection(length1 / line1.getLengthSI(), length2 / line2.getLengthSI(), combo));
                     }
 
                     double dx = end2.x - start2.x;
                     double dy = end2.y - start2.y;
                     cumul2 += Math.sqrt(dx * dx + dy * dy);
                 }
 
                 double dx = end1.x - start1.x;
                 double dy = end1.y - start1.y;
                 cumul1 += Math.sqrt(dx * dx + dy * dy);
             }
 
             return out;
         }
 
         /** {@inheritDoc} */
         @Override
         public String toString()
         {
             return "Intersection [fraction1=" + this.fraction1 + ", fraction2=" + this.fraction2 + ", combo=" + this.combo
                     + "]";
         }
 
     }
 
     /**
      * Generator for width.
      * <p>
      * Copyright (c) 2013-2023 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://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
      * @author <a href="https://dittlab.tudelft.nl">Wouter Schakel</a>
      */
     public interface WidthGenerator
     {
 
         /**
          * Returns the begin width of this lane.
          * @param lane Lane; lane
          * @param fraction double; fraction
          * @return begin width of this lane
          */
         double getWidth(Lane lane, double fraction);
 
     }
 
     /**
      * Generator with fixed width.
      * <p>
      * Copyright (c) 2013-2023 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://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
      * @author <a href="https://dittlab.tudelft.nl">Wouter Schakel</a>
      */
     public static class FixedWidthGenerator implements WidthGenerator
     {
 
         /** Fixed width. */
         private final double width;
 
         /**
          * Constructor with width.
          * @param width Length; width
          */
         public FixedWidthGenerator(final Length width)
         {
             this.width = width.si;
         }
 
         /** {@inheritDoc} */
         @Override
         public final double getWidth(final Lane lane, final double fraction)
         {
             return this.width;
         }
 
         /** {@inheritDoc} */
         @Override
         public final String toString()
         {
             return "FixedWidthGenerator [width=" + this.width + "]";
         }
 
     }
 
     /**
      * Generator with width factor on actual lane width.
      * <p>
      * Copyright (c) 2013-2023 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://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
      * @author <a href="https://dittlab.tudelft.nl">Wouter Schakel</a>
      */
     public static class RelativeWidthGenerator implements WidthGenerator
     {
 
         /** Width factor. */
         private final double factor;
 
         /**
          * Constructor with width factor.
          * @param factor double; width factor
          */
         public RelativeWidthGenerator(final double factor)
         {
             this.factor = factor;
         }
 
         /** {@inheritDoc} */
         @Override
         public final double getWidth(final Lane lane, final double fraction)
         {
             return lane.getWidth(fraction).si * this.factor;
         }
 
         /** {@inheritDoc} */
         @Override
         public final String toString()
         {
             return "RelativeWidthGenerator [factor=" + this.factor + "]";
         }
 
     }
 
     /** */
     @SuppressWarnings("checkstyle:visibilitymodifier")
     static class ConflictBuilderRecord
     {
         /** */
         final Lane lane1;
 
         /** */
         final Set<Lane> down1;
 
         /** */
         final Set<Lane> up1;
 
         /** */
         final Lane lane2;
 
         /** */
         final Set<Lane> down2;
 
         /** */
         final Set<Lane> up2;
 
         /** */
         final boolean permitted;
 
         /** */
         final OtsSimulatorInterface simulator;
 
         /** */
         final WidthGenerator widthGenerator;
 
         /** */
         final Map<Lane, OtsLine3d> leftEdges;
 
         /** */
         final Map<Lane, OtsLine3d> rightEdges;
 
         /**
          * Stores conflicts about a single lane pair.
          * @param lane1 Lane; lane 1
          * @param down1 Set&lt;Lane&gt;; downstream lanes 1
          * @param up1 Set&lt;Lane&gt;; upstream lanes 1
          * @param lane2 Lane; lane 2
          * @param down2 Set&lt;Lane&gt;; downstream lane 2
          * @param up2 Set&lt;Lane&gt;; upstream lanes 2
          * @param permitted boolean; conflict permitted by traffic control
          * @param simulator OtsSimulatorInterface; simulator
          * @param widthGenerator WidthGenerator; width generator
          * @param leftEdges Map&lt;Lane, OtsLine3d&gt;; cache of left edge lines
          * @param rightEdges Map&lt;Lane, OtsLine3d&gt;; cache of right edge lines
          */
         @SuppressWarnings("checkstyle:parameternumber")
         ConflictBuilderRecord(final Lane lane1, final Set<Lane> down1, final Set<Lane> up1, final Lane lane2,
                 final Set<Lane> down2, final Set<Lane> up2, final boolean permitted, final OtsSimulatorInterface simulator,
                 final WidthGenerator widthGenerator, final Map<Lane, OtsLine3d> leftEdges,
                 final Map<Lane, OtsLine3d> rightEdges)
         {
             this.lane1 = lane1;
             this.down1 = down1;
             this.up1 = up1;
             this.lane2 = lane2;
             this.down2 = down2;
             this.up2 = up2;
             this.permitted = permitted;
             this.simulator = simulator;
             this.widthGenerator = widthGenerator;
             this.leftEdges = leftEdges;
             this.rightEdges = rightEdges;
         }
     }
 }