Pair programming with @Nanokie on a world swapper plugin :D

foundation-chaos/src/main/kotlin/gay/pizza/foundation/chaos/ChaosTools.kt

@@ -1,7 +1,11 @@
 package gay.pizza.foundation.chaos
 
 import org.bukkit.Location
+import org.bukkit.Server
 import org.bukkit.entity.Player
 
 fun Location.nearestPlayer(): Player? =
   world?.players?.minByOrNull { it.location.distance(this) }
+
+fun Server.randomPlayer(): Player? =
+  onlinePlayers.randomOrNull()

foundation-chaos/src/main/kotlin/gay/pizza/foundation/chaos/modules/ChaosModules.kt

@@ -9,6 +9,7 @@ object ChaosModules {
     KillRandomPlayer(plugin),
     TntAllPlayers(plugin),
     MegaTnt(plugin),
-    PlayerSwap(plugin)
+    PlayerSwap(plugin),
+    WorldSwapper(plugin)
   ).shuffled()
 }

foundation-chaos/src/main/kotlin/gay/pizza/foundation/chaos/modules/WorldSwapper.kt

@@ -0,0 +1,48 @@
+package gay.pizza.foundation.chaos.modules
+
+import gay.pizza.foundation.chaos.randomPlayer
+import org.bukkit.ChunkSnapshot
+import org.bukkit.plugin.Plugin
+
+class WorldSwapper(val plugin: Plugin) : ChaosModule {
+  override fun id(): String = "world-swapper"
+  override fun name(): String = "World Swapper"
+  override fun what(): String = "Swaps the world vertically on activation, and un-swaps it on deactivation."
+
+  var snapshot: ChunkSnapshot? = null
+
+  override fun activate() {
+    val player = plugin.server.randomPlayer() ?: return
+    val chunk = player.world.getChunkAt(player.location)
+    val localSnapshot = chunk.chunkSnapshot
+
+    for (x in 0..15) {
+      for (z in 0..15) {
+        val heightRange = (chunk.world.minHeight + 1) until chunk.world.maxHeight
+        for (y in heightRange) {
+          val targetBlock = chunk.getBlock(x, y, z)
+          val inverseY = heightRange.random()
+          val nextBlock = localSnapshot.getBlockData(x, inverseY, z)
+          targetBlock.setBlockData(nextBlock, true)
+        }
+      }
+    }
+    snapshot = localSnapshot
+  }
+
+  override fun deactivate() {
+    val localSnapshot = snapshot ?: return
+    val world = plugin.server.getWorld(localSnapshot.worldName) ?: return
+    val chunk = world.getChunkAt(localSnapshot.x, localSnapshot.z)
+
+    for (x in 0..15) {
+      for (z in 0..15) {
+        val heightRange = chunk.world.minHeight + 1 until chunk.world.maxHeight
+        for (y in heightRange) {
+          val originalBlock = localSnapshot.getBlockData(x, y, z)
+          chunk.getBlock(x, y, z).blockData = originalBlock
+        }
+      }
+    }
+  }
+}