## #43: Prevent players from swimming up waterfalls

modules/development/src/main/java/net/hollowcube/server/dev/Main.java

@@ -69,9 +69,28 @@ public static void main(String[] args) {
             player.setAllowFlying(true);
 
             // Testing
-            event.getSpawnInstance().setBlock(5, 43, 5, Ore.fromNamespaceId("unnamed:gold_ore").asBlock());
-            event.getSpawnInstance().setBlock(4, 43, 5, Ore.fromNamespaceId("unnamed:diamond_ore").asBlock());
-            player.getInventory().addItemStack(Item.fromNamespaceId("unnamed:diamond_pickaxe").asItemStack());
+            event.getSpawnInstance().setBlock(5, 43, 5, Ore.fromNamespaceId("starlight:gold_ore").asBlock());
+            event.getSpawnInstance().setBlock(4, 43, 5, Ore.fromNamespaceId("starlight:diamond_ore").asBlock());
+
+            event.getSpawnInstance().setBlock(10, 40, 5, Block.BUBBLE_COLUMN);
+            event.getSpawnInstance().setBlock(10, 41, 5, Block.BUBBLE_COLUMN);
+            event.getSpawnInstance().setBlock(10, 42, 5, Block.BUBBLE_COLUMN);
+            event.getSpawnInstance().setBlock(10, 43, 5, Block.BUBBLE_COLUMN);
+            event.getSpawnInstance().setBlock(10, 44, 5, Block.BUBBLE_COLUMN);
+            event.getSpawnInstance().setBlock(10, 45, 5, Block.BUBBLE_COLUMN);
+            event.getSpawnInstance().setBlock(10, 46, 5, Block.BUBBLE_COLUMN);
+            event.getSpawnInstance().setBlock(10, 47, 5, Block.BUBBLE_COLUMN);
+            event.getSpawnInstance().setBlock(10, 48, 5, Block.BUBBLE_COLUMN);
+
+            event.getSpawnInstance().setBlock(11, 40, 5, Block.WATER);
+            event.getSpawnInstance().setBlock(11, 41, 5, Block.WATER);
+            event.getSpawnInstance().setBlock(11, 42, 5, Block.WATER);
+            event.getSpawnInstance().setBlock(11, 43, 5, Block.WATER);
+            event.getSpawnInstance().setBlock(11, 44, 5, Block.WATER);
+            event.getSpawnInstance().setBlock(11, 45, 5, Block.WATER);
+            event.getSpawnInstance().setBlock(11, 46, 5, Block.WATER);
+            event.getSpawnInstance().setBlock(11, 47, 5, Block.WATER);
+            event.getSpawnInstance().setBlock(11, 48, 5, Block.WATER);
 
             //todo this needs to be done elsewhere
             player.addEffect(new Potion(PotionEffect.MINING_FATIGUE, (byte) -1, Short.MAX_VALUE, (byte) 0x0));

modules/player/src/main/java/net/hollowcube/player/PlayerImpl.java

@@ -3,6 +3,7 @@
 import net.hollowcube.modifiers.ModifierList;
 import net.hollowcube.modifiers.ModifierOperation;
 import net.hollowcube.modifiers.ModifierType;
+import net.hollowcube.player.event.PlayerBubbleColumnSinkEvent;
 import net.hollowcube.player.event.PlayerLongDiggingStartEvent;
 import net.minestom.server.MinecraftServer;
 import net.minestom.server.coordinate.Point;
@@ -13,6 +14,7 @@
 import net.minestom.server.instance.block.BlockFace;
 import net.minestom.server.network.packet.client.ClientPacket;
 import net.minestom.server.network.packet.client.play.ClientPlayerDiggingPacket;
+import net.minestom.server.network.packet.client.play.ClientPlayerPositionPacket;
 import net.minestom.server.network.packet.server.play.BlockBreakAnimationPacket;
 import net.minestom.server.network.player.PlayerConnection;
 import org.jetbrains.annotations.NotNull;
@@ -34,6 +36,10 @@ public class PlayerImpl extends Player {
     private int diggingBlockMaxHealth = 0;
     private BlockFace diggingFace = null;
 
+    // Bubble column sink event state
+    private int bubbleColumnSinkEnergyLevel = -1;
+    private boolean wasLastSeenInBubbleColumn = false;
+
     private final Map<String, ModifierList> currentModifiers = new HashMap<>();
 
     private final Logger logger = LoggerFactory.getLogger(PlayerImpl.class);
@@ -58,6 +64,10 @@ private void handlePacket(PlayerPacketEvent event) {
         if (packet instanceof ClientPlayerDiggingPacket diggingPacket) {
             handleDiggingPacket(diggingPacket);
         }
+
+        if (packet instanceof ClientPlayerPositionPacket positionPacket) {
+            handlePositionPacket(positionPacket);
+        }
     }
 
     private void handleDiggingPacket(ClientPlayerDiggingPacket packet) {
@@ -94,6 +104,37 @@ private void handleDiggingPacket(ClientPlayerDiggingPacket packet) {
         }
     }
 
+    private void handlePositionPacket(ClientPlayerPositionPacket packet) {
+        if (packet.onGround()) {
+
+        }
+        else {
+            if (this.getInstance().getBlock(this.getPosition()) == Block.BUBBLE_COLUMN) {
+                //TODO: I think we want to make this part of a whole PlayerInWaterHandler or something, and on top of that,
+                // we would have to make a BlockComponentHandler or something to encapsulate it. I wonder if @Matt has a
+                // suggestion on this.
+
+                // PlayerBubbleColumnSinkEvent playerBubbleColumnSinkEvent = new PlayerBubbleColumnSinkEvent(this, this.getFood());
+                // MinecraftServer.getGlobalEventHandler().call(playerBubbleColumnSinkEvent);
+
+                if (!this.wasLastSeenInBubbleColumn) {
+                    this.wasLastSeenInBubbleColumn = true;
+                    this.bubbleColumnSinkEnergyLevel = this.getFood();
+                    //TODO: This does not work lol it is not implemented in minestom to get rid of the player's
+                    // ability to sprint when they have hunger below 7
+                    this.setFood(6);
+                }
+            }
+            else if (this.wasLastSeenInBubbleColumn) {
+                if (this.getInstance().getBlock(this.getPosition()) != Block.BUBBLE_COLUMN) {
+                    this.wasLastSeenInBubbleColumn = false;
+                    this.setFood(this.bubbleColumnSinkEnergyLevel);
+                    this.bubbleColumnSinkEnergyLevel = -1;
+                }
+            }
+        }
+    }
+
     private void tickLongDigging() {
         if (diggingBlock == null) return;
 

modules/player/src/main/java/net/hollowcube/player/event/PlayerBubbleColumnSinkEvent.java

@@ -0,0 +1,37 @@
+package net.hollowcube.player.event;
+
+import net.minestom.server.entity.Player;
+import net.minestom.server.event.trait.PlayerInstanceEvent;
+import net.minestom.server.instance.block.Block;
+import org.jetbrains.annotations.NotNull;
+
+public class PlayerBubbleColumnSinkEvent implements PlayerInstanceEvent {
+    private final Player player;
+    private final int energyLevel;
+
+    public PlayerBubbleColumnSinkEvent(Player player, int energyLevel) {
+        this.player = player;
+        this.energyLevel = energyLevel;
+    }
+
+    @Override
+    public @NotNull Player getPlayer() {
+        return player;
+    }
+
+    public int getEnergyLevel() {
+        return energyLevel;
+    }
+
+    public void cancelPlayerSwimming() {
+        if (player.getInstance().getBlock(player.getPosition()) == Block.BUBBLE_COLUMN) {
+            player.setFood(6);
+        }
+    }
+
+    public void restorePlayerEnergy() {
+        if (player.getInstance().getBlock(player.getPosition()) != Block.BUBBLE_COLUMN) {
+            player.setFood(energyLevel);
+        }
+    }
+}