Merge pull request #518 from pylonmc/vaan/fix/pipe-dupe

Fix pipe TRANSMUTATION

Author: LordIdra

pylon-core/src/main/kotlin/io/github/pylonmc/pylon/core/fluid/placement/FluidPipePlacementService.kt

@@ -16,6 +16,7 @@ import org.bukkit.event.EventHandler
 import org.bukkit.event.Listener
 import org.bukkit.event.player.PlayerItemHeldEvent
 import org.bukkit.event.player.PlayerQuitEvent
+import org.bukkit.event.player.PlayerSwapHandItemsEvent
 import org.bukkit.event.world.ChunkUnloadEvent
 import org.bukkit.inventory.EquipmentSlot
 import java.util.UUID
@@ -164,6 +165,23 @@ internal object FluidPipePlacementService : Listener {
         }
     }
 
+    @EventHandler
+    private fun onSwap(event: PlayerSwapHandItemsEvent) {
+        if (!connectionsInProgress.containsKey(event.getPlayer())) return
+
+        val mainHandPylon = PylonItem.fromStack(event.mainHandItem)
+        if (mainHandPylon is FluidPipe) {
+            event.isCancelled = true
+            return
+        }
+
+        val otherHandPylon = PylonItem.fromStack(event.offHandItem)
+        if (otherHandPylon is FluidPipe) {
+            event.isCancelled = true
+            return
+        }
+    }
+
     /**
      * Intended to prevent issues if players teleport away while placing a pipe
      */