From c014901b7a4741c3a88290c2a08537bf6fe9dccd Mon Sep 17 00:00:00 2001
From: Frank van der Heijden <22407829+FrankHeijden@users.noreply.github.com>
Date: Thu, 10 Dec 2020 20:13:44 +0100
Subject: [PATCH] Prevent doublechests forming on claim boundary (#1054)

---
 .../GriefPrevention/BlockEventHandler.java    | 48 +++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/src/main/java/me/ryanhamshire/GriefPrevention/BlockEventHandler.java b/src/main/java/me/ryanhamshire/GriefPrevention/BlockEventHandler.java
index 76252fe..868bad2 100644
--- a/src/main/java/me/ryanhamshire/GriefPrevention/BlockEventHandler.java
+++ b/src/main/java/me/ryanhamshire/GriefPrevention/BlockEventHandler.java
@@ -34,6 +34,7 @@ import org.bukkit.block.BlockState;
 import org.bukkit.block.Hopper;
 import org.bukkit.block.PistonMoveReaction;
 import org.bukkit.block.data.BlockData;
+import org.bukkit.block.data.type.Chest;
 import org.bukkit.block.data.type.Dispenser;
 import org.bukkit.entity.Fireball;
 import org.bukkit.entity.Item;
@@ -287,6 +288,10 @@ public class BlockEventHandler implements Listener
         //if the block is being placed within or under an existing claim
         PlayerData playerData = this.dataStore.getPlayerData(player.getUniqueId());
         Claim claim = this.dataStore.getClaimAt(block.getLocation(), true, playerData.lastClaim);
+
+        //If block is a chest, don't allow a DoubleChest to form across a claim boundary
+        denyConnectingDoubleChestsAcrossClaimBoundary(claim, block, player);
+        
         if (claim != null)
         {
             playerData.lastClaim = claim;
@@ -491,6 +496,49 @@ public class BlockEventHandler implements Listener
         return false;
     }
 
+    private static final BlockFace[] HORIZONTAL_DIRECTIONS = new BlockFace[] {
+            BlockFace.NORTH,
+            BlockFace.EAST,
+            BlockFace.SOUTH,
+            BlockFace.WEST
+    };
+    private void denyConnectingDoubleChestsAcrossClaimBoundary(Claim claim, Block block, Player player)
+    {
+        UUID claimOwner = null;
+        if (claim != null)
+            claimOwner = claim.getOwnerID();
+
+        // Check for double chests placed just outside the claim boundary
+        if (block.getBlockData() instanceof Chest)
+        {
+            for (BlockFace face : HORIZONTAL_DIRECTIONS)
+            {
+                Block relative = block.getRelative(face);
+                if (!(relative.getBlockData() instanceof Chest)) continue;
+
+                Claim relativeClaim = this.dataStore.getClaimAt(relative.getLocation(), true, claim);
+                UUID relativeClaimOwner = relativeClaim == null ? null : relativeClaim.getOwnerID();
+
+                // Chests outside claims should connect (both null)
+                // and chests inside the same claim should connect (equal)
+                if (Objects.equals(claimOwner, relativeClaimOwner)) break;
+
+                // Change both chests to singular chests
+                Chest chest = (Chest) block.getBlockData();
+                chest.setType(Chest.Type.SINGLE);
+                block.setBlockData(chest);
+
+                Chest relativeChest = (Chest) relative.getBlockData();
+                relativeChest.setType(Chest.Type.SINGLE);
+                relative.setBlockData(relativeChest);
+
+                // Resend relative chest block to prevent visual bug
+                player.sendBlockChange(relative.getLocation(), relativeChest);
+                break;
+            }
+        }
+    }
+
     // Prevent pistons pushing blocks into or out of claims.
     @EventHandler(ignoreCancelled = true, priority = EventPriority.LOWEST)
     public void onBlockPistonExtend(BlockPistonExtendEvent event)