Add AxiomHandshakeEvent and AxiomModifyWorldEvent

src/main/java/com/moulberry/axiom/event/AxiomHandshakeEvent.java

@@ -0,0 +1,52 @@
+package com.moulberry.axiom.event;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.Event;
+import org.bukkit.event.HandlerList;
+import org.jetbrains.annotations.NotNull;
+
+public class AxiomHandshakeEvent extends Event implements Cancellable {
+
+    private static final HandlerList HANDLERS = new HandlerList();
+
+    private final Player player;
+    private boolean cancelled = false;
+    private int maxBufferSize = 0x100000;
+
+    public AxiomHandshakeEvent(Player player) {
+        this.player = player;
+    }
+
+    public Player getPlayer() {
+        return this.player;
+    }
+
+    public int getMaxBufferSize() {
+        return this.maxBufferSize;
+    }
+
+    public void setMaxBufferSize(int maxBufferSize) {
+        this.maxBufferSize = maxBufferSize;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return this.cancelled;
+    }
+
+    @Override
+    public void setCancelled(boolean cancel) {
+        this.cancelled = cancel;
+    }
+
+    public static HandlerList getHandlerList() {
+        return HANDLERS;
+    }
+
+    @Override
+    public @NotNull HandlerList getHandlers() {
+        return HANDLERS;
+    }
+
+}

src/main/java/com/moulberry/axiom/event/AxiomModifyWorldEvent.java

@@ -0,0 +1,54 @@
+package com.moulberry.axiom.event;
+
+import org.bukkit.World;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.Event;
+import org.bukkit.event.HandlerList;
+import org.jetbrains.annotations.NotNull;
+
+public class AxiomModifyWorldEvent extends Event implements Cancellable {
+
+    private static final HandlerList HANDLERS = new HandlerList();
+
+    private final Player player;
+    private final World world;
+    private boolean cancelled;
+
+    public AxiomModifyWorldEvent(Player player, World world) {
+        this.player = player;
+        this.world = world;
+
+        // By default, changes are only allowed if the player is in the same world
+        // This behaviour can be changed by doing setCancelled(false)
+        this.cancelled = player.getWorld() != world;
+    }
+
+    public World getWorld() {
+        return world;
+    }
+
+    public Player getPlayer() {
+        return this.player;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return this.cancelled;
+    }
+
+    @Override
+    public void setCancelled(boolean cancel) {
+        this.cancelled = cancel;
+    }
+
+    public static HandlerList getHandlerList() {
+        return HANDLERS;
+    }
+
+    @Override
+    public @NotNull HandlerList getHandlers() {
+        return HANDLERS;
+    }
+
+}

src/main/java/com/moulberry/axiom/packet/AxiomBigPayloadHandler.java

@@ -39,6 +39,7 @@ public class AxiomBigPayloadHandler extends ByteToMessageDecoder {
                         ServerPlayer player = connection.getPlayer();
                         if (player != null && player.getBukkitEntity().hasPermission("axiom.*")) {
                             listener.onReceive(player, buf);
+                            in.readerIndex(in.writerIndex());
                             return;
                         }
                     }

src/main/java/com/moulberry/axiom/packet/HelloPacketListener.java

@@ -3,11 +3,13 @@ package com.moulberry.axiom.packet;
 import com.moulberry.axiom.AxiomConstants;
 import com.moulberry.axiom.AxiomPaper;
 import com.moulberry.axiom.View;
+import com.moulberry.axiom.event.AxiomHandshakeEvent;
 import com.moulberry.axiom.persistence.ItemStackDataType;
 import com.moulberry.axiom.persistence.UUIDDataType;
 import io.netty.buffer.Unpooled;
 import net.kyori.adventure.text.Component;
 import net.minecraft.network.FriendlyByteBuf;
+import org.bukkit.Bukkit;
 import org.bukkit.NamespacedKey;
 import org.bukkit.craftbukkit.v1_20_R1.inventory.CraftItemStack;
 import org.bukkit.entity.Player;
@@ -46,13 +48,20 @@ public class HelloPacketListener implements PluginMessageListener {
             return;
         }
 
+        // Call handshake event
+        AxiomHandshakeEvent handshakeEvent = new AxiomHandshakeEvent(player);
+        Bukkit.getPluginManager().callEvent(handshakeEvent);
+        if (handshakeEvent.isCancelled()) {
+            return;
+        }
+
         activeAxiomPlayers.add(player.getUniqueId());
 
         // Enable
         FriendlyByteBuf buf = new FriendlyByteBuf(Unpooled.buffer());
         buf.writeBoolean(true);
         buf.writeByte(0); // todo: world properties
-        buf.writeInt(0x100000); // Max Buffer Size
+        buf.writeInt(handshakeEvent.getMaxBufferSize()); // Max Buffer Size
         buf.writeBoolean(false); // No source info
         buf.writeBoolean(false); // No source settings
         buf.writeVarInt(5); // Maximum Reach

src/main/java/com/moulberry/axiom/packet/SetBlockBufferPacketListener.java

@@ -4,6 +4,7 @@ import com.moulberry.axiom.AxiomPaper;
 import com.moulberry.axiom.buffer.BiomeBuffer;
 import com.moulberry.axiom.buffer.BlockBuffer;
 import com.moulberry.axiom.buffer.CompressedBlockEntity;
+import com.moulberry.axiom.event.AxiomModifyWorldEvent;
 import io.netty.buffer.Unpooled;
 import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
 import it.unimi.dsi.fastutil.shorts.Short2ObjectMap;
@@ -31,6 +32,10 @@ import net.minecraft.world.level.chunk.LevelChunkSection;
 import net.minecraft.world.level.chunk.PalettedContainer;
 import net.minecraft.world.level.levelgen.Heightmap;
 import net.minecraft.world.level.lighting.LightEngine;
+import org.bukkit.Bukkit;
+import org.bukkit.NamespacedKey;
+import org.bukkit.World;
+import org.bukkit.craftbukkit.v1_20_R1.CraftWorld;
 import org.bukkit.craftbukkit.v1_20_R1.entity.CraftPlayer;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.messaging.PluginMessageListener;
@@ -66,6 +71,16 @@ public class SetBlockBufferPacketListener {
         if (server == null) return;
 
         ResourceKey<Level> worldKey = friendlyByteBuf.readResourceKey(Registries.DIMENSION);
+        NamespacedKey namespacedKey = new NamespacedKey(worldKey.location().getNamespace(), worldKey.location().getPath());
+        World world = Bukkit.getWorld(namespacedKey);
+        if (world != null) {
+            AxiomModifyWorldEvent modifyWorldEvent = new AxiomModifyWorldEvent(player.getBukkitEntity(), world);
+            Bukkit.getPluginManager().callEvent(modifyWorldEvent);
+            if (modifyWorldEvent.isCancelled()) return;
+        } else {
+            return;
+        }
+
         friendlyByteBuf.readUUID(); // Discard, we don't need to associate buffers
         boolean continuation = friendlyByteBuf.readBoolean();
 

src/main/java/com/moulberry/axiom/packet/SetBlockPacketListener.java

@@ -1,6 +1,7 @@
 package com.moulberry.axiom.packet;
 
 import com.moulberry.axiom.AxiomPaper;
+import com.moulberry.axiom.event.AxiomModifyWorldEvent;
 import io.netty.buffer.Unpooled;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.SectionPos;
@@ -15,6 +16,7 @@ import net.minecraft.world.level.chunk.LevelChunk;
 import net.minecraft.world.level.chunk.LevelChunkSection;
 import net.minecraft.world.level.levelgen.Heightmap;
 import net.minecraft.world.level.lighting.LightEngine;
+import org.bukkit.Bukkit;
 import org.bukkit.craftbukkit.v1_20_R1.entity.CraftPlayer;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.messaging.PluginMessageListener;
@@ -52,6 +54,12 @@ public class SetBlockPacketListener implements PluginMessageListener {
             return;
         }
 
+        // Check if player is allowed to modify this world
+        AxiomModifyWorldEvent modifyWorldEvent = new AxiomModifyWorldEvent(bukkitPlayer, bukkitPlayer.getWorld());
+        Bukkit.getPluginManager().callEvent(modifyWorldEvent);
+        if (modifyWorldEvent.isCancelled()) return;
+
+        // Read packet
         FriendlyByteBuf friendlyByteBuf = new FriendlyByteBuf(Unpooled.wrappedBuffer(message));
         BlockPos blockPos = friendlyByteBuf.readBlockPos();
         BlockState blockState = friendlyByteBuf.readById(Block.BLOCK_STATE_REGISTRY);
@@ -60,6 +68,7 @@ public class SetBlockPacketListener implements PluginMessageListener {
 
         ServerPlayer player = ((CraftPlayer)bukkitPlayer).getHandle();
 
+        // Update blocks
         if (updateNeighbors) {
             player.level().setBlock(blockPos, blockState, 3);
         } else {