--- a/net/minecraft/server/WorldServer.java
+++ b/net/minecraft/server/WorldServer.java
@@ -35,6 +35,18 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
+// CraftBukkit start
+import java.util.logging.Level;
+import org.bukkit.Bukkit;
+import org.bukkit.WeatherType;
+import org.bukkit.craftbukkit.event.CraftEventFactory;
+import org.bukkit.craftbukkit.util.WorldUUID;
+import org.bukkit.event.entity.CreatureSpawnEvent;
+import org.bukkit.event.server.MapInitializeEvent;
+import org.bukkit.event.weather.LightningStrikeEvent;
+import org.bukkit.event.world.TimeSkipEvent;
+// CraftBukkit end
+
 public class WorldServer extends World implements GeneratorAccessSeed {
 
     public static final BlockPosition a = new BlockPosition(100, 50, 0);
@@ -46,7 +58,7 @@
     private final ChunkProviderServer chunkProvider;
     boolean tickingEntities;
     private final MinecraftServer server;
-    public final IWorldDataServer worldDataServer;
+    public final WorldDataServer worldDataServer; // CraftBukkit - type
     public boolean savingDisabled;
     private boolean everyoneSleeping;
     private int emptyTime;
@@ -63,8 +75,23 @@
     private final StructureManager structureManager;
     private final boolean Q;
 
-    public WorldServer(MinecraftServer minecraftserver, Executor executor, Convertable.ConversionSession convertable_conversionsession, IWorldDataServer iworlddataserver, ResourceKey<World> resourcekey, DimensionManager dimensionmanager, WorldLoadListener worldloadlistener, ChunkGenerator chunkgenerator, boolean flag, long i, List<MobSpawner> list, boolean flag1) {
-        super(iworlddataserver, resourcekey, dimensionmanager, minecraftserver::getMethodProfiler, false, flag, i);
+
+    // CraftBukkit start
+    private int tickPosition;
+    public final Convertable.ConversionSession convertable;
+    public final UUID uuid;
+
+    public Chunk getChunkIfLoaded(int x, int z) {
+        return this.chunkProvider.getChunkAt(x, z, false);
+    }
+
+    // Add env and gen to constructor, WorldData -> WorldDataServer
+    public WorldServer(MinecraftServer minecraftserver, Executor executor, Convertable.ConversionSession convertable_conversionsession, IWorldDataServer iworlddataserver, ResourceKey<World> resourcekey, DimensionManager dimensionmanager, WorldLoadListener worldloadlistener, ChunkGenerator chunkgenerator, boolean flag, long i, List<MobSpawner> list, boolean flag1, org.bukkit.World.Environment env, org.bukkit.generator.ChunkGenerator gen) {
+        super(iworlddataserver, resourcekey, dimensionmanager, minecraftserver::getMethodProfiler, false, flag, i, gen, env);
+        this.pvpMode = minecraftserver.getPVP();
+        convertable = convertable_conversionsession;
+        uuid = WorldUUID.getUUID(convertable_conversionsession.folder.toFile());
+        // CraftBukkit end
         this.nextTickListBlock = new TickListServer<>(this, (block) -> {
             return block == null || block.getBlockData().isAir();
         }, IRegistry.BLOCK::getKey, this::b);
@@ -76,10 +103,17 @@
         this.Q = flag1;
         this.server = minecraftserver;
         this.mobSpawners = list;
-        this.worldDataServer = iworlddataserver;
+        // CraftBukkit start
+        this.worldDataServer = (WorldDataServer) iworlddataserver;
+        worldDataServer.world = this;
+        if (gen != null) {
+            chunkgenerator = new org.bukkit.craftbukkit.generator.CustomChunkGenerator(this, chunkgenerator, gen);
+        }
+
         this.chunkProvider = new ChunkProviderServer(this, convertable_conversionsession, minecraftserver.getDataFixer(), minecraftserver.getDefinedStructureManager(), executor, chunkgenerator, minecraftserver.getPlayerList().getViewDistance(), minecraftserver.isSyncChunkWrites(), worldloadlistener, () -> {
             return minecraftserver.E().getWorldPersistentData();
         });
+        // CraftBukkit end
         this.portalTravelAgent = new PortalTravelAgent(this);
         this.P();
         this.Q();
@@ -91,14 +125,48 @@
             iworlddataserver.setGameType(minecraftserver.getGamemode());
         }
 
-        this.structureManager = new StructureManager(this, minecraftserver.getSaveData().getGeneratorSettings());
+        this.structureManager = new StructureManager(this, this.worldDataServer.getGeneratorSettings()); // CraftBukkit
         if (this.getDimensionManager().isCreateDragonBattle()) {
-            this.dragonBattle = new EnderDragonBattle(this, minecraftserver.getSaveData().getGeneratorSettings().getSeed(), minecraftserver.getSaveData().C());
+            this.dragonBattle = new EnderDragonBattle(this, this.worldDataServer.getGeneratorSettings().getSeed(), this.worldDataServer.C()); // CraftBukkit
         } else {
             this.dragonBattle = null;
         }
+        this.getServer().addWorld(this.getWorld()); // CraftBukkit
+    }
+
+    // CraftBukkit start
+    @Override
+    protected TileEntity getTileEntity(BlockPosition pos, boolean validate) {
+        TileEntity result = super.getTileEntity(pos, validate);
+        if (!validate || Thread.currentThread() != this.serverThread) {
+            // SPIGOT-5378: avoid deadlock, this can be called in loading logic (i.e lighting) but getType() will block on chunk load
+            return result;
+        }
+        Block type = getType(pos).getBlock();
 
+        if (result != null && type != Blocks.AIR) {
+            if (!result.getTileType().isValidBlock(type)) {
+                result = fixTileEntity(pos, type, result);
+            }
+        }
+
+        return result;
+    }
+
+    private TileEntity fixTileEntity(BlockPosition pos, Block type, TileEntity found) {
+        this.getServer().getLogger().log(Level.SEVERE, "Block at {0}, {1}, {2} is {3} but has {4}" + ". "
+                + "Bukkit will attempt to fix this, but there may be additional damage that we cannot recover.", new Object[]{pos.getX(), pos.getY(), pos.getZ(), type, found});
+
+        if (type instanceof ITileEntity) {
+            TileEntity replacement = ((ITileEntity) type).createTile(this);
+            replacement.world = this;
+            this.setTileEntity(pos, replacement);
+            return replacement;
+        } else {
+            return found;
+        }
     }
+    // CraftBukkit end
 
     public void a(int i, int j, boolean flag, boolean flag1) {
         this.worldDataServer.a(i);
@@ -189,6 +257,7 @@
             this.rainLevel = MathHelper.a(this.rainLevel, 0.0F, 1.0F);
         }
 
+        /* CraftBukkit start
         if (this.lastRainLevel != this.rainLevel) {
             this.server.getPlayerList().a((Packet) (new PacketPlayOutGameStateChange(PacketPlayOutGameStateChange.h, this.rainLevel)), this.getDimensionKey());
         }
@@ -207,18 +276,47 @@
             this.server.getPlayerList().sendAll(new PacketPlayOutGameStateChange(PacketPlayOutGameStateChange.h, this.rainLevel));
             this.server.getPlayerList().sendAll(new PacketPlayOutGameStateChange(PacketPlayOutGameStateChange.i, this.thunderLevel));
         }
+        // */
+        for (int idx = 0; idx < this.players.size(); ++idx) {
+            if (((EntityPlayer) this.players.get(idx)).world == this) {
+                ((EntityPlayer) this.players.get(idx)).tickWeather();
+            }
+        }
+
+        if (flag != this.isRaining()) {
+            // Only send weather packets to those affected
+            for (int idx = 0; idx < this.players.size(); ++idx) {
+                if (((EntityPlayer) this.players.get(idx)).world == this) {
+                    ((EntityPlayer) this.players.get(idx)).setPlayerWeather((!flag ? WeatherType.DOWNFALL : WeatherType.CLEAR), false);
+                }
+            }
+        }
+        for (int idx = 0; idx < this.players.size(); ++idx) {
+            if (((EntityPlayer) this.players.get(idx)).world == this) {
+                ((EntityPlayer) this.players.get(idx)).updateWeather(this.lastRainLevel, this.rainLevel, this.lastThunderLevel, this.thunderLevel);
+            }
+        }
+        // CraftBukkit end
 
         if (this.everyoneSleeping && this.players.stream().noneMatch((entityplayer) -> {
-            return !entityplayer.isSpectator() && !entityplayer.isDeeplySleeping();
+            return !entityplayer.isSpectator() && !entityplayer.isDeeplySleeping() && !entityplayer.fauxSleeping; // CraftBukkit
         })) {
-            this.everyoneSleeping = false;
+            // CraftBukkit start
+            long l = this.worldData.getDayTime() + 24000L;
+            TimeSkipEvent event = new TimeSkipEvent(this.getWorld(), TimeSkipEvent.SkipReason.NIGHT_SKIP, (l - l % 24000L) - this.getDayTime());
             if (this.getGameRules().getBoolean(GameRules.DO_DAYLIGHT_CYCLE)) {
-                long l = this.worldData.getDayTime() + 24000L;
+                getServer().getPluginManager().callEvent(event);
+                if (!event.isCancelled()) {
+                    this.setDayTime(this.getDayTime() + event.getSkipAmount());
+                }
 
-                this.setDayTime(l - l % 24000L);
             }
 
-            this.wakeupPlayers();
+            if (!event.isCancelled()) {
+                this.everyoneSleeping = false;
+                this.wakeupPlayers();
+            }
+            // CraftBukkit end
             if (this.getGameRules().getBoolean(GameRules.DO_WEATHER_CYCLE)) {
                 this.clearWeather();
             }
@@ -240,7 +338,7 @@
         this.aj();
         this.ticking = false;
         gameprofilerfiller.exitEnter("entities");
-        boolean flag3 = !this.players.isEmpty() || !this.getForceLoadedChunks().isEmpty();
+        boolean flag3 = true || !this.players.isEmpty() || !this.getForceLoadedChunks().isEmpty(); // CraftBukkit - this prevents entity cleanup, other issues on servers with no players
 
         if (flag3) {
             this.resetEmptyTime();
@@ -259,6 +357,7 @@
                 Entity entity = (Entity) entry.getValue();
                 Entity entity1 = entity.getVehicle();
 
+                /* CraftBukkit start - We prevent spawning in general, so this butchering is not needed
                 if (!this.server.getSpawnAnimals() && (entity instanceof EntityAnimal || entity instanceof EntityWaterAnimal)) {
                     entity.die();
                 }
@@ -266,6 +365,7 @@
                 if (!this.server.getSpawnNPCs() && entity instanceof NPC) {
                     entity.die();
                 }
+                // CraftBukkit end */
 
                 gameprofilerfiller.enter("checkDespawn");
                 if (!entity.dead) {
@@ -340,7 +440,7 @@
     }
 
     private void wakeupPlayers() {
-        ((List) this.players.stream().filter(EntityLiving::isSleeping).collect(Collectors.toList())).forEach((entityplayer) -> {
+        (this.players.stream().filter(EntityLiving::isSleeping).collect(Collectors.toList())).forEach((entityplayer) -> { // CraftBukkit - decompile error
             entityplayer.wakeup(false, false);
         });
     }
@@ -367,14 +467,14 @@
                     entityhorseskeleton.t(true);
                     entityhorseskeleton.setAgeRaw(0);
                     entityhorseskeleton.setPosition((double) blockposition.getX(), (double) blockposition.getY(), (double) blockposition.getZ());
-                    this.addEntity(entityhorseskeleton);
+                    this.addEntity(entityhorseskeleton, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.LIGHTNING); // CraftBukkit
                 }
 
                 EntityLightning entitylightning = (EntityLightning) EntityTypes.LIGHTNING_BOLT.a((World) this);
 
                 entitylightning.d(Vec3D.c((BaseBlockPosition) blockposition));
                 entitylightning.setEffect(flag1);
-                this.addEntity(entitylightning);
+                this.strikeLightning(entitylightning, org.bukkit.event.weather.LightningStrikeEvent.Cause.WEATHER); // CraftBukkit
             }
         }
 
@@ -385,11 +485,11 @@
             BiomeBase biomebase = this.getBiome(blockposition);
 
             if (biomebase.a(this, blockposition1)) {
-                this.setTypeUpdate(blockposition1, Blocks.ICE.getBlockData());
+                org.bukkit.craftbukkit.event.CraftEventFactory.handleBlockFormEvent(this, blockposition1, Blocks.ICE.getBlockData(), null); // CraftBukkit
             }
 
             if (flag && biomebase.b(this, blockposition)) {
-                this.setTypeUpdate(blockposition, Blocks.SNOW.getBlockData());
+                org.bukkit.craftbukkit.event.CraftEventFactory.handleBlockFormEvent(this, blockposition, Blocks.SNOW.getBlockData(), null); // CraftBukkit
             }
 
             if (flag && this.getBiome(blockposition1).c() == BiomeBase.Precipitation.RAIN) {
@@ -436,7 +536,7 @@
     protected BlockPosition a(BlockPosition blockposition) {
         BlockPosition blockposition1 = this.getHighestBlockYAt(HeightMap.Type.MOTION_BLOCKING, blockposition);
         AxisAlignedBB axisalignedbb = (new AxisAlignedBB(blockposition1, new BlockPosition(blockposition1.getX(), this.getBuildHeight(), blockposition1.getZ()))).g(3.0D);
-        List<EntityLiving> list = this.a(EntityLiving.class, axisalignedbb, (entityliving) -> {
+        List<EntityLiving> list = this.a(EntityLiving.class, axisalignedbb, (java.util.function.Predicate<EntityLiving>) (entityliving) -> { // CraftBukkit - decompile error
             return entityliving != null && entityliving.isAlive() && this.e(entityliving.getChunkCoordinates());
         });
 
@@ -465,7 +565,7 @@
             while (iterator.hasNext()) {
                 EntityPlayer entityplayer = (EntityPlayer) iterator.next();
 
-                if (entityplayer.isSpectator()) {
+                if (entityplayer.isSpectator() || (entityplayer.fauxSleeping && !entityplayer.isSleeping())) { // CraftBukkit
                     ++i;
                 } else if (entityplayer.isSleeping()) {
                     ++j;
@@ -483,10 +583,22 @@
     }
 
     private void clearWeather() {
-        this.worldDataServer.setWeatherDuration(0);
+        // CraftBukkit start
         this.worldDataServer.setStorm(false);
-        this.worldDataServer.setThunderDuration(0);
+        // If we stop due to everyone sleeping we should reset the weather duration to some other random value.
+        // Not that everyone ever manages to get the whole server to sleep at the same time....
+        if (!this.worldDataServer.hasStorm()) {
+            this.worldDataServer.setWeatherDuration(0);
+        }
+        // CraftBukkit end
         this.worldDataServer.setThundering(false);
+        // CraftBukkit start
+        // If we stop due to everyone sleeping we should reset the weather duration to some other random value.
+        // Not that everyone ever manages to get the whole server to sleep at the same time....
+        if (!this.worldDataServer.isThundering()) {
+            this.worldDataServer.setThunderDuration(0);
+        }
+        // CraftBukkit end
     }
 
     public void resetEmptyTime() {
@@ -527,6 +639,7 @@
                 });
                 gameprofilerfiller.c("tickNonPassenger");
                 entity.tick();
+                entity.postTick(); // CraftBukkit
                 gameprofilerfiller.exit();
             }
 
@@ -615,6 +728,7 @@
         ChunkProviderServer chunkproviderserver = this.getChunkProvider();
 
         if (!flag1) {
+            org.bukkit.Bukkit.getPluginManager().callEvent(new org.bukkit.event.world.WorldSaveEvent(getWorld())); // CraftBukkit
             if (iprogressupdate != null) {
                 iprogressupdate.a(new ChatMessage("menu.savingLevel"));
             }
@@ -626,11 +740,19 @@
 
             chunkproviderserver.save(flag);
         }
+
+        // CraftBukkit start - moved from MinecraftServer.saveChunks
+        WorldServer worldserver1 = this;
+
+        worldDataServer.a(worldserver1.getWorldBorder().t());
+        worldDataServer.setCustomBossEvents(this.server.getBossBattleCustomData().save());
+        convertable.a(this.server.customRegistry, this.worldDataServer, this.server.getPlayerList().save());
+        // CraftBukkit end
     }
 
     private void ai() {
         if (this.dragonBattle != null) {
-            this.server.getSaveData().a(this.dragonBattle.a());
+            this.worldDataServer.a(this.dragonBattle.a()); // CraftBukkit
         }
 
         this.getChunkProvider().getWorldPersistentData().a();
@@ -691,11 +813,24 @@
 
     @Override
     public boolean addEntity(Entity entity) {
-        return this.addEntity0(entity);
+        // CraftBukkit start
+        return this.addEntity0(entity, CreatureSpawnEvent.SpawnReason.DEFAULT);
+    }
+
+    @Override
+    public boolean addEntity(Entity entity, CreatureSpawnEvent.SpawnReason reason) {
+        return this.addEntity0(entity, reason);
+        // CraftBukkit end
     }
 
     public boolean addEntitySerialized(Entity entity) {
-        return this.addEntity0(entity);
+        // CraftBukkit start
+        return this.addEntitySerialized(entity, CreatureSpawnEvent.SpawnReason.DEFAULT);
+    }
+
+    public boolean addEntitySerialized(Entity entity, CreatureSpawnEvent.SpawnReason reason) {
+        return this.addEntity0(entity, reason);
+        // CraftBukkit end
     }
 
     public void addEntityTeleport(Entity entity) {
@@ -745,13 +880,18 @@
         this.registerEntity(entityplayer);
     }
 
-    private boolean addEntity0(Entity entity) {
+    // CraftBukkit start
+    private boolean addEntity0(Entity entity, CreatureSpawnEvent.SpawnReason spawnReason) {
         if (entity.dead) {
-            WorldServer.LOGGER.warn("Tried to add entity {} but it was marked as removed already", EntityTypes.getName(entity.getEntityType()));
+            // WorldServer.LOGGER.warn("Tried to add entity {} but it was marked as removed already", EntityTypes.getName(entity.getEntityType())); // CraftBukkit
             return false;
         } else if (this.isUUIDTaken(entity)) {
             return false;
         } else {
+            if (!CraftEventFactory.doEntityAddEventCalling(this, entity, spawnReason)) {
+                return false;
+            }
+            // CraftBukkit end
             IChunkAccess ichunkaccess = this.getChunkAt(MathHelper.floor(entity.locX() / 16.0D), MathHelper.floor(entity.locZ() / 16.0D), ChunkStatus.FULL, entity.attachedToPlayer);
 
             if (!(ichunkaccess instanceof Chunk)) {
@@ -780,7 +920,7 @@
         if (entity1 == null) {
             return false;
         } else {
-            WorldServer.LOGGER.warn("Trying to add entity with duplicated UUID {}. Existing {}#{}, new: {}#{}", uuid, EntityTypes.getName(entity1.getEntityType()), entity1.getId(), EntityTypes.getName(entity.getEntityType()), entity.getId());
+            // WorldServer.LOGGER.warn("Trying to add entity with duplicated UUID {}. Existing {}#{}, new: {}#{}", uuid, EntityTypes.getName(entity1.getEntityType()), entity1.getId(), EntityTypes.getName(entity.getEntityType()), entity.getId()); // CraftBukkit
             return true;
         }
     }
@@ -809,11 +949,16 @@
     }
 
     public boolean addAllEntitiesSafely(Entity entity) {
+        // CraftBukkit start
+        return this.addAllEntitiesSafely(entity, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.DEFAULT);
+    }
+
+    public boolean addAllEntitiesSafely(Entity entity, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason reason) {
+        // CraftBukkit end
         if (entity.co().anyMatch(this::isUUIDTaken)) {
             return false;
         } else {
-            this.addAllEntities(entity);
-            return true;
+            return this.addAllEntities(entity, reason); // CraftBukkit
         }
     }
 
@@ -863,10 +1008,17 @@
         }
 
         this.getScoreboard().a(entity);
+        // CraftBukkit start - SPIGOT-5278
+        if (entity instanceof EntityDrowned) {
+            this.navigators.remove(((EntityDrowned) entity).navigationWater);
+            this.navigators.remove(((EntityDrowned) entity).navigationLand);
+        } else
+        // CraftBukkit end
         if (entity instanceof EntityInsentient) {
             this.navigators.remove(((EntityInsentient) entity).getNavigation());
         }
 
+        entity.valid = false; // CraftBukkit
     }
 
     private void registerEntity(Entity entity) {
@@ -887,9 +1039,16 @@
 
             this.entitiesByUUID.put(entity.getUniqueID(), entity);
             this.getChunkProvider().addEntity(entity);
+            // CraftBukkit start - SPIGOT-5278
+            if (entity instanceof EntityDrowned) {
+                this.navigators.add(((EntityDrowned) entity).navigationWater);
+                this.navigators.add(((EntityDrowned) entity).navigationLand);
+            } else
+            // CraftBukkit end
             if (entity instanceof EntityInsentient) {
                 this.navigators.add(((EntityInsentient) entity).getNavigation());
             }
+            entity.valid = true; // CraftBukkit
         }
 
     }
@@ -919,10 +1078,33 @@
         this.everyoneSleeping();
     }
 
+    // CraftBukkit start
+    public boolean strikeLightning(Entity entitylightning) {
+        return this.strikeLightning(entitylightning, LightningStrikeEvent.Cause.UNKNOWN);
+    }
+
+    public boolean strikeLightning(Entity entitylightning, LightningStrikeEvent.Cause cause) {
+        LightningStrikeEvent lightning = new LightningStrikeEvent(this.getWorld(), (org.bukkit.entity.LightningStrike) entitylightning.getBukkitEntity(), cause);
+        this.getServer().getPluginManager().callEvent(lightning);
+
+        if (lightning.isCancelled()) {
+            return false;
+        }
+
+        return this.addEntity(entitylightning);
+    }
+    // CraftBukkit end
+
     @Override
     public void a(int i, BlockPosition blockposition, int j) {
         Iterator iterator = this.server.getPlayerList().getPlayers().iterator();
 
+        // CraftBukkit start
+        EntityHuman entityhuman = null;
+        Entity entity = this.getEntity(i);
+        if (entity instanceof EntityHuman) entityhuman = (EntityHuman) entity;
+        // CraftBukkit end
+
         while (iterator.hasNext()) {
             EntityPlayer entityplayer = (EntityPlayer) iterator.next();
 
@@ -931,6 +1113,12 @@
                 double d1 = (double) blockposition.getY() - entityplayer.locY();
                 double d2 = (double) blockposition.getZ() - entityplayer.locZ();
 
+                // CraftBukkit start
+                if (entityhuman != null && entityhuman instanceof EntityPlayer && !entityplayer.getBukkitEntity().canSee(((EntityPlayer) entityhuman).getBukkitEntity())) {
+                    continue;
+                }
+                // CraftBukkit end
+
                 if (d0 * d0 + d1 * d1 + d2 * d2 < 1024.0D) {
                     entityplayer.playerConnection.sendPacket(new PacketPlayOutBlockBreakAnimation(i, blockposition, j));
                 }
@@ -991,10 +1179,20 @@
 
     @Override
     public Explosion createExplosion(@Nullable Entity entity, @Nullable DamageSource damagesource, @Nullable ExplosionDamageCalculator explosiondamagecalculator, double d0, double d1, double d2, float f, boolean flag, Explosion.Effect explosion_effect) {
+        // CraftBukkit start
+        Explosion explosion = super.createExplosion(entity, damagesource, explosiondamagecalculator, d0, d1, d2, f, flag, explosion_effect);
+
+        if (explosion.wasCanceled) {
+            return explosion;
+        }
+
+        /* Remove
         Explosion explosion = new Explosion(this, entity, damagesource, explosiondamagecalculator, d0, d1, d2, f, flag, explosion_effect);
 
         explosion.a();
         explosion.a(false);
+        */
+        // CraftBukkit end - TODO: Check if explosions are still properly implemented
         if (explosion_effect == Explosion.Effect.NONE) {
             explosion.clearBlocks();
         }
@@ -1059,13 +1257,20 @@
     }
 
     public <T extends ParticleParam> int a(T t0, double d0, double d1, double d2, int i, double d3, double d4, double d5, double d6) {
-        PacketPlayOutWorldParticles packetplayoutworldparticles = new PacketPlayOutWorldParticles(t0, false, d0, d1, d2, (float) d3, (float) d4, (float) d5, (float) d6, i);
+        // CraftBukkit - visibility api support
+        return sendParticles(null, t0, d0, d1, d2, i, d3, d4, d5, d6, false);
+    }
+
+    public <T extends ParticleParam> int sendParticles(EntityPlayer sender, T t0, double d0, double d1, double d2, int i, double d3, double d4, double d5, double d6, boolean force) {
+        PacketPlayOutWorldParticles packetplayoutworldparticles = new PacketPlayOutWorldParticles(t0, force, d0, d1, d2, (float) d3, (float) d4, (float) d5, (float) d6, i);
+        // CraftBukkit end
         int j = 0;
 
         for (int k = 0; k < this.players.size(); ++k) {
             EntityPlayer entityplayer = (EntityPlayer) this.players.get(k);
+            if (sender != null && !entityplayer.getBukkitEntity().canSee(sender.getBukkitEntity())) continue; // CraftBukkit
 
-            if (this.a(entityplayer, false, d0, d1, d2, packetplayoutworldparticles)) {
+            if (this.a(entityplayer, force, d0, d1, d2, packetplayoutworldparticles)) { // CraftBukkit
                 ++j;
             }
         }
@@ -1107,7 +1312,7 @@
 
     @Nullable
     public BlockPosition a(StructureGenerator<?> structuregenerator, BlockPosition blockposition, int i, boolean flag) {
-        return !this.server.getSaveData().getGeneratorSettings().shouldGenerateMapFeatures() ? null : this.getChunkProvider().getChunkGenerator().findNearestMapFeature(this, structuregenerator, blockposition, i, flag);
+        return !this.worldDataServer.getGeneratorSettings().shouldGenerateMapFeatures() ? null : this.getChunkProvider().getChunkGenerator().findNearestMapFeature(this, structuregenerator, blockposition, i, flag); // CraftBukkit
     }
 
     @Nullable
@@ -1145,7 +1350,13 @@
     @Override
     public WorldMap a(String s) {
         return (WorldMap) this.getMinecraftServer().E().getWorldPersistentData().b(() -> {
-            return new WorldMap(s);
+            // CraftBukkit start
+            // We only get here when the data file exists, but is not a valid map
+            WorldMap newMap = new WorldMap(s);
+            MapInitializeEvent event = new MapInitializeEvent(newMap.mapView);
+            Bukkit.getServer().getPluginManager().callEvent(event);
+            return newMap;
+            // CraftBukkit end
         }, s);
     }
 
@@ -1456,6 +1667,11 @@
     @Override
     public void update(BlockPosition blockposition, Block block) {
         if (!this.isDebugWorld()) {
+            // CraftBukkit start
+            if (populating) {
+                return;
+            }
+            // CraftBukkit end
             this.applyPhysics(blockposition, block);
         }
 
@@ -1470,12 +1686,12 @@
     }
 
     public boolean isFlatWorld() {
-        return this.server.getSaveData().getGeneratorSettings().isFlatWorld();
+        return this.worldDataServer.getGeneratorSettings().isFlatWorld(); // CraftBukkit
     }
 
     @Override
     public long getSeed() {
-        return this.server.getSaveData().getGeneratorSettings().getSeed();
+        return this.worldDataServer.getGeneratorSettings().getSeed(); // CraftBukkit
     }
 
     @Nullable
@@ -1494,16 +1710,32 @@
     }
 
     public static void a(WorldServer worldserver) {
+        // CraftBukkit start
+        WorldServer.a(worldserver, null);
+    }
+
+    public static void a(WorldServer worldserver, Entity entity) {
+        // CraftBukkit end
         BlockPosition blockposition = WorldServer.a;
         int i = blockposition.getX();
         int j = blockposition.getY() - 2;
         int k = blockposition.getZ();
 
+        // CraftBukkit start
+        org.bukkit.craftbukkit.util.BlockStateListPopulator blockList = new org.bukkit.craftbukkit.util.BlockStateListPopulator(worldserver);
         BlockPosition.b(i - 2, j + 1, k - 2, i + 2, j + 3, k + 2).forEach((blockposition1) -> {
-            worldserver.setTypeUpdate(blockposition1, Blocks.AIR.getBlockData());
+            blockList.setTypeAndData(blockposition1, Blocks.AIR.getBlockData(), 3);
         });
         BlockPosition.b(i - 2, j, k - 2, i + 2, j, k + 2).forEach((blockposition1) -> {
-            worldserver.setTypeUpdate(blockposition1, Blocks.OBSIDIAN.getBlockData());
+            blockList.setTypeAndData(blockposition1, Blocks.OBSIDIAN.getBlockData(), 3);
         });
+        org.bukkit.World bworld = worldserver.getWorld();
+        org.bukkit.event.world.PortalCreateEvent portalEvent = new org.bukkit.event.world.PortalCreateEvent((List<org.bukkit.block.BlockState>) (List) blockList.getList(), bworld, (entity == null) ? null : entity.getBukkitEntity(), org.bukkit.event.world.PortalCreateEvent.CreateReason.END_PLATFORM);
+
+        worldserver.getServer().getPluginManager().callEvent(portalEvent);
+        if (!portalEvent.isCancelled()) {
+            blockList.updateList();
+        }
+        // CraftBukkit end
     }
 }