all should work now

src/main/java/me/fivevl/staff/Config.kt

@@ -3,14 +3,17 @@ package me.fivevl.staff
 import org.bukkit.configuration.file.FileConfiguration
 
 object Config {
-    var config: FileConfiguration? = null
+    private fun getConfig(): FileConfiguration {
-    val mustBePlayer = config?.getString("must-be-player")
+        return Utils.getConfig()
-    val noPermission = config?.getString("no-permission")
+    }
-    val toggleStaffmode = config?.getString("toggle-staffmode")
+    val mustBePlayer = getConfig().getString("must-be-player")!!
+    val noPermission = getConfig().getString("no-permission")!!
+    val toggleStaffmode = getConfig().getString("toggle-staffmode")!!
+    val toggleVanish = getConfig().getString("toggle-vanish")!!
     val staffmodeHotbar = HashMap<Int, String>().apply {
-        config?.getConfigurationSection("staffmode-hotbar")?.getKeys(false)?.forEach {
+        getConfig().getConfigurationSection("staffmode-hotbar")?.getKeys(false)?.forEach {
-            put(it.toInt(), config?.getString("staffmode-hotbar.$it")!!)
+            put(it.toInt(), getConfig().getString("staffmode-hotbar.$it")!!)
         }
     }
-    val toggleVanish = config?.getString("toggle-vanish")
+    val disableStaffmodeItem = getConfig().getString("disable-staffmode-item")!!
 }

src/main/java/me/fivevl/staff/Items.kt

@@ -0,0 +1,19 @@
+package me.fivevl.staff
+
+import org.bukkit.Material
+import org.bukkit.inventory.ItemStack
+
+enum class Items(val item: ItemStack) {
+    DISABLE_STAFFMODE(getStaffmodeItem()),
+    FREEZE_WAND(ItemStack(Material.STICK)),
+    INVENTORY_WAND(ItemStack(Material.STICK)),
+    KB_STICK(ItemStack(Material.STICK)),
+    VANISH_ITEM(ItemStack(Material.STICK)),
+}
+@Suppress("deprecation")
+private fun getStaffmodeItem(): ItemStack {
+    val item = ItemStack(Material.LIME_DYE)
+    val meta = item.itemMeta
+    meta.setDisplayName(Utils.hex(Utils.getPlaceholders(null, Config.disableStaffmodeItem)))
+    return item
+}

src/main/java/me/fivevl/staff/Main.kt

@@ -11,7 +11,6 @@ class Main : JavaPlugin() {
         Utils.instance = this
 
         saveDefaultConfig()
-        Config.config = config
 
         getCommand("staffmode")!!.setExecutor(StaffModeCommand())
         getCommand("vanish")!!.setExecutor(VanishCommand())

src/main/java/me/fivevl/staff/Utils.kt

@@ -4,6 +4,7 @@ import me.clip.placeholderapi.PlaceholderAPI
 import net.md_5.bungee.api.ChatColor
 import org.bukkit.Bukkit
 import org.bukkit.Material
+import org.bukkit.configuration.file.FileConfiguration
 import org.bukkit.entity.Player
 import org.bukkit.inventory.ItemStack
 import org.bukkit.inventory.PlayerInventory
@@ -11,7 +12,7 @@ import java.util.regex.Pattern
 
 object Utils {
     var instance: Main? = null
-    private val inStaffmode = HashMap<Player, PlayerInventory>()
+    val inStaffmode = HashMap<Player, PlayerInventory>()
     val inVanish = ArrayList<Player>()
     @Suppress("deprecation")
     fun hex(s: String): String {
@@ -20,7 +21,7 @@ object Utils {
         var match = pattern.matcher(s)
         while (match.find()) {
             val color = s.substring(match.start(), match.end())
-            s2 = s2.replace(color, ChatColor.of(color).toString() + "")
+            s2 = s2.replace(color, ChatColor.of(color).toString())
             match = pattern.matcher(s2)
         }
         return ChatColor.translateAlternateColorCodes('&', s2)
@@ -39,31 +40,33 @@ object Utils {
             for (i: Int in Config.staffmodeHotbar.keys) {
                 var item = ItemStack(Material.AIR)
                 when (Config.staffmodeHotbar[i]) {
-                    "DISABLE_STAFFMODE" -> item = ItemStack(Material.AIR)
+                    "DISABLE_STAFFMODE" -> item = Items.DISABLE_STAFFMODE.item
-                    "FREEZE_WAND" -> item = ItemStack(Material.AIR)
+                    "FREEZE_WAND" -> item = Items.FREEZE_WAND.item
-                    "INVENTORY_WAND" -> item = ItemStack(Material.AIR)
+                    "INVENTORY_WAND" -> item = Items.INVENTORY_WAND.item
-                    "KB_STICK" -> item = ItemStack(Material.AIR)
+                    "KB_STICK" -> item = Items.KB_STICK.item
-                    "VANISH_ITEM" -> item = ItemStack(Material.AIR)
+                    "VANISH_ITEM" -> item = Items.VANISH_ITEM.item
                 }
                 p.inventory.setItem(i - 1, item)
             }
         }
-        p.sendMessage(hex(getPlaceholders(p, Config.toggleStaffmode!!)))
+        p.sendMessage(hex(getPlaceholders(p, Config.toggleStaffmode)))
     }
-
     fun toggleVanish(p: Player) {
         if (inVanish.contains(p)) {
             for (ps in Bukkit.getOnlinePlayers()) {
                 ps.showPlayer(instance!!, p)
             }
             inVanish.remove(p)
-            p.sendMessage(hex(getPlaceholders(p, Config.toggleVanish!!)))
         } else {
             for (ps in Bukkit.getOnlinePlayers()) {
                 ps.hidePlayer(instance!!, p)
             }
             inVanish.add(p)
-            p.sendMessage(hex(getPlaceholders(p, Config.toggleVanish!!)))
+        }
-        }
+        p.sendMessage(hex(getPlaceholders(p, Config.toggleVanish)))
+    }
+
+    fun getConfig(): FileConfiguration {
+        return instance!!.config
     }
 }

src/main/java/me/fivevl/staff/commands/StaffModeCommand.kt

@@ -10,12 +10,12 @@ import org.bukkit.entity.Player
 class StaffModeCommand : CommandExecutor {
     override fun onCommand(sender: CommandSender, command: Command, label: String, args: Array<out String>): Boolean {
         if (sender !is Player) {
-            sender.sendMessage(Utils.hex(Utils.getPlaceholders(null, Config.mustBePlayer!!)))
+            sender.sendMessage(Utils.hex(Utils.getPlaceholders(null, Config.mustBePlayer)))
             return true
         }
         val p = sender.player!!
         if (!p.hasPermission("staff.staffmode")) {
-            p.sendMessage(Utils.hex(Utils.getPlaceholders(p, Config.noPermission!!)))
+            p.sendMessage(Utils.hex(Utils.getPlaceholders(p, Config.noPermission)))
             return true
         }
         Utils.toggleStaffmode(p)

src/main/java/me/fivevl/staff/commands/VanishCommand.kt

@@ -1,11 +1,24 @@
 package me.fivevl.staff.commands
 
+import me.fivevl.staff.Config
+import me.fivevl.staff.Utils
 import org.bukkit.command.Command
 import org.bukkit.command.CommandExecutor
 import org.bukkit.command.CommandSender
+import org.bukkit.entity.Player
 
 class VanishCommand : CommandExecutor {
     override fun onCommand(sender: CommandSender, command: Command, label: String, args: Array<out String>): Boolean {
+        if (sender !is Player) {
+            sender.sendMessage(Utils.hex(Utils.getPlaceholders(null, Config.mustBePlayer)))
+            return true
+        }
+        val p = sender.player!!
+        if (!p.hasPermission("staff.vanish")) {
+            p.sendMessage(Utils.hex(Utils.getPlaceholders(p, Config.noPermission)))
+            return true
+        }
+        Utils.toggleVanish(p)
         return true
     }
 

src/main/java/me/fivevl/staff/listeners/JoinListener.kt

@@ -4,13 +4,30 @@ import me.fivevl.staff.Utils
 import org.bukkit.event.EventHandler
 import org.bukkit.event.Listener
 import org.bukkit.event.player.PlayerJoinEvent
+import org.bukkit.event.player.PlayerQuitEvent
 
 class JoinListener : Listener {
+    @Suppress("deprecation")
     @EventHandler
     fun onJoin(e: PlayerJoinEvent) {
+        e.joinMessage = null
         val p = e.player
         for (ps in Utils.inVanish) {
             p.hidePlayer(Utils.instance!!, ps)
         }
     }
+    @Suppress("deprecation")
+    @EventHandler
+    fun onLeave (e: PlayerQuitEvent) {
+        e.quitMessage = null
+        val p = e.player
+        if (Utils.inVanish.contains(p)) {
+            Utils.inVanish.remove(p)
+        }
+        if (Utils.inStaffmode.contains(p)) {
+            p.inventory.clear()
+            p.inventory.contents = Utils.inStaffmode[p]!!.contents
+            Utils.inStaffmode.remove(p)
+        }
+    }
 }

src/main/resources/config.yml

@@ -16,3 +16,4 @@ staffmode-hotbar: # List of items to give the player when they toggle staffmode,
   7: "AIR"
   8: "AIR"
   9: "AIR"
+disable-staffmode-item: "&aDisable staffmode" # Item name of the item that disables staffmode

src/main/resources/plugin.yml

@@ -4,6 +4,8 @@ main: me.fivevl.staff.Main
 api-version: 1.18
 authors: [ 5vl ]
 description: A staffing plugin.
+depend:
+  - PlaceholderAPI
 commands:
   staffmode:
     description: The command to go into staffmode.