Prevent sand physics sign destruction.

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>com.Acrobot.ChestShop</groupId>
     <artifactId>ChestShop</artifactId>
-    <version>3.12</version>
+    <version>3.13</version>
 
     <properties>
         <maven.compiler.source>8</maven.compiler.source>
@@ -114,4 +114,4 @@
 
     </dependencies>
 
-</project>
+</project>

src/main/java/com/Acrobot/ChestShop/ChestShop.java

@@ -93,6 +93,7 @@ private void registerEvents() {
         blockBreak blockBreak = new blockBreak();
         registerEvent(Event.Type.BLOCK_BREAK, blockBreak);
         registerEvent(Event.Type.BLOCK_PLACE, new blockPlace());
+        registerEvent(Event.Type.BLOCK_PHYSICS, new blockPhysics());
         registerEvent(Event.Type.SIGN_CHANGE, new signChange());
         registerEvent(Event.Type.PLAYER_LOGIN, new playerLogin(), Event.Priority.Monitor);
         registerEvent(Event.Type.PLAYER_INTERACT, new playerInteract(), Event.Priority.Highest);

src/main/java/com/Acrobot/ChestShop/Listeners/blockPhysics.java

@@ -0,0 +1,55 @@
+package com.Acrobot.ChestShop.Listeners;
+
+import com.Acrobot.ChestShop.Utils.uSign;
+import org.bukkit.Material;
+import org.bukkit.block.Block;
+import org.bukkit.block.BlockFace;
+import org.bukkit.block.Sign;
+import org.bukkit.event.block.BlockListener;
+import org.bukkit.event.block.BlockPhysicsEvent;
+import org.bukkit.material.Attachable;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class blockPhysics extends BlockListener {
+    @Override
+    public void onBlockPhysics(BlockPhysicsEvent event) {
+        if (event.isCancelled()) {
+            return;
+        }
+
+        Block block = event.getBlock();
+        if (block.getType() != Material.SAND && block.getType() != Material.GRAVEL) {
+            return;
+        }
+
+        if (shouldCancel(event.getBlock().getRelative(BlockFace.UP))) {
+            event.setCancelled(true);
+
+            return;
+        }
+
+        List<BlockFace> horizontals = Arrays.asList(
+            BlockFace.NORTH,
+            BlockFace.EAST,
+            BlockFace.SOUTH,
+            BlockFace.WEST
+        );
+        for (BlockFace face: horizontals) {
+            Block neighbor = event.getBlock().getRelative(face);
+            if (neighbor.getState() != null && (neighbor.getState().getData() instanceof Attachable)) {
+                Attachable data = (Attachable) neighbor.getState().getData();
+                if (data.getAttachedFace() == face.getOppositeFace() && shouldCancel(neighbor)) {
+                    event.setCancelled(true);
+
+                    return;
+                }
+            }
+        }
+    }
+
+    private boolean shouldCancel(Block block) {
+        return uSign.isSign(block) && uSign.isValid((Sign) block.getState());
+    }
+}