Use guard clauses when possible

In preparation for Folia support.

src/main/java/pw/kaboom/icontrolu/ControlPlayer.java

@@ -1,264 +0,0 @@
-package pw.kaboom.icontrolu;
-
-import org.bukkit.Bukkit;
-import org.bukkit.entity.Entity;
-import org.bukkit.entity.Player;
-import org.bukkit.event.EventHandler;
-import org.bukkit.event.EventPriority;
-import org.bukkit.event.Listener;
-import org.bukkit.event.block.Action;
-import org.bukkit.event.entity.EntityDamageEvent;
-import org.bukkit.event.player.AsyncPlayerChatEvent;
-import org.bukkit.event.player.PlayerAnimationEvent;
-import org.bukkit.event.player.PlayerCommandPreprocessEvent;
-import org.bukkit.event.player.PlayerDropItemEvent;
-import org.bukkit.event.player.PlayerInteractEvent;
-import org.bukkit.event.player.PlayerMoveEvent;
-import org.bukkit.event.player.PlayerQuitEvent;
-import org.bukkit.event.player.PlayerRespawnEvent;
-import org.bukkit.inventory.EquipmentSlot;
-import org.bukkit.plugin.java.JavaPlugin;
-import org.bukkit.potion.PotionEffect;
-import org.bukkit.potion.PotionEffectType;
-import org.bukkit.scheduler.BukkitRunnable;
-import org.bukkit.scoreboard.Scoreboard;
-import org.bukkit.scoreboard.Team;
-
-import com.destroystokyo.paper.event.server.ServerTickStartEvent;
-
-import net.kyori.adventure.text.Component;
-
-import pw.kaboom.icontrolu.utilities.PlayerList;
-
-class ControlPlayer implements Listener {
-    private static String CHAT_PREFIX = "\ud800iControlUChat\ud800";
-
-    @EventHandler
-    private void onAsyncPlayerChat(final AsyncPlayerChatEvent event) {
-        final Player player = event.getPlayer();
-
-        if (PlayerList.getController(player.getUniqueId()) != null) {
-            if (event.getMessage().startsWith(CHAT_PREFIX)) {
-                final int prefixLength = CHAT_PREFIX.length();
-
-                event.setMessage(
-                    event.getMessage().substring(prefixLength)
-                );
-            } else {
-                event.setCancelled(true);
-            }
-
-        } else if (PlayerList.getTarget(player.getUniqueId()) != null) {
-            final Player target = PlayerList.getTarget(player.getUniqueId());
-
-            new BukkitRunnable() {
-                @Override
-                public void run() {
-                    // Add prefix to prevent messages from being cancelled
-                    target.chat(CHAT_PREFIX + event.getMessage());
-                }
-            }.runTask(JavaPlugin.getPlugin(Main.class));
-
-            event.setCancelled(true);
-        }
-    }
-
-    @EventHandler
-    private void onEntityDamage(final EntityDamageEvent event) {
-        final Entity player = event.getEntity();
-
-        if (PlayerList.getTarget(player.getUniqueId()) != null) {
-            event.setCancelled(true);
-        }
-    }
-
-    @EventHandler
-    private void onPlayerAnimation(final PlayerAnimationEvent event) {
-        final Player player = event.getPlayer();
-
-        if (PlayerList.getController(player.getUniqueId()) != null) {
-            event.setCancelled(true);
-        }
-    }
-
-    @EventHandler
-    private void onPlayerCommandPreprocess(final PlayerCommandPreprocessEvent event) {
-        final Player player = event.getPlayer();
-
-        if (PlayerList.getController(player.getUniqueId()) != null) {
-            event.setCancelled(true);
-        }
-    }
-
-    @EventHandler
-    private void onPlayerDropItem(final PlayerDropItemEvent event) {
-        final Player player = event.getPlayer();
-
-        if (PlayerList.getController(player.getUniqueId()) != null) {
-            event.setCancelled(true);
-        }
-    }
-
-    @EventHandler
-    private void onPlayerInteract(final PlayerInteractEvent event) {
-        final Player player = event.getPlayer();
-
-        if (PlayerList.getController(player.getUniqueId()) != null) {
-            event.setCancelled(true);
-
-        } else if ((event.getAction() == Action.LEFT_CLICK_AIR
-                || event.getAction() == Action.LEFT_CLICK_BLOCK)
-                && PlayerList.getTarget(player.getUniqueId()) != null) {
-            final Player target = PlayerList.getTarget(player.getUniqueId());
-
-            if (event.getHand() == EquipmentSlot.HAND) {
-                target.swingMainHand();
-            } else if (event.getHand() == EquipmentSlot.OFF_HAND) {
-                target.swingOffHand();
-            }
-        }
-    }
-
-    @EventHandler
-    private void onPlayerMove(final PlayerMoveEvent event) {
-        final Player player = event.getPlayer();
-
-        if (PlayerList.getController(player.getUniqueId()) != null) {
-            event.setCancelled(true);
-        }
-    }
-
-    @EventHandler
-    private void onPlayerQuit(final PlayerQuitEvent event) {
-        final Player player = event.getPlayer();
-
-        for (Player otherPlayer: Bukkit.getOnlinePlayers()) {
-            if (PlayerList.getController(player.getUniqueId()) != null
-                    && PlayerList.getController(player.getUniqueId()).equals(otherPlayer)) {
-                /*
-                  Target disconnects
-                  */
-                PlayerList.removeTarget(otherPlayer.getUniqueId());
-                PlayerList.removeController(player.getUniqueId());
-
-                final Player controller = otherPlayer;
-                final int tickDelay = 200;
-
-                new BukkitRunnable() {
-                    @Override
-                    public void run() {
-                        for (Player allPlayers: Bukkit.getOnlinePlayers()) {
-                            allPlayers.showPlayer(JavaPlugin.getPlugin(Main.class), controller);
-                        }
-
-                        final Scoreboard scoreboard = Bukkit.getScoreboardManager()
-                            .getMainScoreboard();
-                        final Team team = scoreboard.getTeam("icuCollision");
-
-                        if (team != null
-                                && team.hasEntry(controller.getName())) {
-                            team.removeEntry(controller.getName());
-                        }
-
-                        controller.removePotionEffect(PotionEffectType.INVISIBILITY);
-                        controller.sendMessage(Component.text("You are now visible"));
-                    }
-                }.runTaskLater(JavaPlugin.getPlugin(Main.class), tickDelay);
-
-                otherPlayer.sendMessage(Component.text("The player you were controlling has "
-                                        + "disconnected. You are invisible for 10 seconds."));
-
-            } else if (PlayerList.getTarget(player.getUniqueId()) != null
-                    && PlayerList.getTarget(player.getUniqueId()).equals(otherPlayer)) {
-                /*
-                  Controller disconnects
-                  */
-                PlayerList.removeTarget(player.getUniqueId());
-                PlayerList.removeController(otherPlayer.getUniqueId());
-            }
-        }
-    }
-
-    @EventHandler
-    private void onPlayerRespawn(final PlayerRespawnEvent event) {
-        final Player player = event.getPlayer();
-
-        if (PlayerList.getController(player.getUniqueId()) != null) {
-            final Player controller = PlayerList.getController(player.getUniqueId());
-
-            controller.teleportAsync(player.getLocation());
-        }
-    }
-
-    @SuppressWarnings("deprecation")
-    @EventHandler(priority = EventPriority.MONITOR)
-    public void onTickStart(ServerTickStartEvent event) {
-        for (Player target: Bukkit.getOnlinePlayers()) {
-            final Player controller = PlayerList.getController(target.getUniqueId());
-
-            if (controller != null) {
-                for (int i = 0; i < controller.getInventory().getSize(); i++) {
-                    if (controller.getInventory().getItem(i) != null) {
-                        if (!controller.getInventory().getItem(i).equals(
-                                target.getInventory().getItem(i))) {
-                            target.getInventory().setItem(i, controller.getInventory().getItem(i));
-                        }
-                    } else {
-                        target.getInventory().setItem(i, null);
-                    }
-                }
-
-                if (target.getHealth() > 0) {
-                    target.teleportAsync(controller.getLocation());
-                }
-
-                target.setAllowFlight(controller.getAllowFlight());
-                target.setExhaustion(controller.getExhaustion());
-                target.setFlying(controller.isFlying());
-                target.setFoodLevel(controller.getFoodLevel());
-
-                if (controller.getMaxHealth() > 0) {
-                    target.setMaxHealth(controller.getMaxHealth());
-                    target.setHealth(controller.getHealth());
-                }
-
-                target.setLevel(controller.getLevel());
-                target.setSneaking(controller.isSneaking());
-                target.setSprinting(controller.isSprinting());
-
-                for (Player player: Bukkit.getOnlinePlayers()) {
-                    player.hidePlayer(JavaPlugin.getPlugin(Main.class), controller);
-                }
-
-                final Scoreboard scoreboard = Bukkit.getScoreboardManager().getMainScoreboard();
-                Team team = scoreboard.getTeam("icuCollision");
-
-                if (team == null) {
-                    team = scoreboard.registerNewTeam("icuCollision");
-                }
-
-                team.setCanSeeFriendlyInvisibles(false);
-                team.setOption(Team.Option.COLLISION_RULE, Team.OptionStatus.NEVER);
-
-                if (!team.hasEntry(controller.getName())) {
-                    team.addEntry(controller.getName());
-                }
-
-                final int duration = 99999;
-                final int amplifier = 0;
-                final boolean ambient = false;
-                final boolean particles = false;
-
-                controller.addPotionEffect(
-                    new PotionEffect(
-                        PotionEffectType.INVISIBILITY,
-                        duration,
-                        amplifier,
-                        ambient,
-                        particles
-                    )
-                );
-            }
-        }
-    }
-}

src/main/java/pw/kaboom/icontrolu/Main.java

@@ -10,48 +10,21 @@ import org.bukkit.scoreboard.Team;
 import net.kyori.adventure.text.Component;
 
 import pw.kaboom.icontrolu.commands.CommandIcu;
-import pw.kaboom.icontrolu.utilities.PlayerList;
+import pw.kaboom.icontrolu.PlayerControl;
 
 public final class Main extends JavaPlugin {
     @Override
     public void onEnable() {
-        /* Setup scoreboard team to prevent player collisions */
-        final Scoreboard scoreboard = Bukkit.getScoreboardManager().getMainScoreboard();
-        final Team team = scoreboard.getTeam("icuCollision");
-        if (team != null) {
-            team.unregister();
-        }
-
         /* Commands */
         this.getCommand("icu").setExecutor(new CommandIcu());
 
-        this.getServer().getPluginManager().registerEvents(new ControlPlayer(), this);
+        /* Modules */
+        PlayerControl.enable();
+        this.getServer().getPluginManager().registerEvents(new PlayerControl(), this);
     }
 
     @Override
     public void onDisable() {
-        for (Player controller: Bukkit.getOnlinePlayers()) {
-            final Player target = PlayerList.getTarget(controller.getUniqueId());
-
-            if (target != null) {
-                for (Player player: Bukkit.getOnlinePlayers()) {
-                    player.showPlayer(this, controller);
-                }
-
-                final Scoreboard scoreboard = Bukkit.getScoreboardManager().getMainScoreboard();
-                final Team team = scoreboard.getTeam("icuCollision");
-
-                if (team != null) {
-                    team.unregister();
-                }
-
-                controller.removePotionEffect(PotionEffectType.INVISIBILITY);
-                controller.sendMessage(
-                    Component.text("You are no longer controlling \"")
-                        .append(Component.text(target.getName()))
-                        .append(Component.text("\" due to server reload"))
-                );
-            }
-        }
+        PlayerControl.disable();
     }
 }

src/main/java/pw/kaboom/icontrolu/commands/CommandIcu.java

@@ -10,7 +10,6 @@ import org.bukkit.command.ConsoleCommandSender;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.java.JavaPlugin;
 import org.bukkit.potion.PotionEffectType;
-import org.bukkit.scheduler.BukkitRunnable;
 import org.bukkit.scoreboard.Scoreboard;
 import org.bukkit.scoreboard.Team;
 
@@ -18,106 +17,100 @@ import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.format.NamedTextColor;
 
 import pw.kaboom.icontrolu.Main;
-import pw.kaboom.icontrolu.utilities.PlayerList;
+import pw.kaboom.icontrolu.PlayerControl;
 
 public final class CommandIcu implements CommandExecutor {
     private void controlCommand(final Player controller, final String label, final String[] args) {
         if (args.length == 1) {
             controller.sendMessage(Component
                 .text("Usage: /" + label + " control <player>", NamedTextColor.RED));
-        } else {
-            Player target = Bukkit.getPlayer(args[1]);
-
-            if (target == null && args[1].matches("([a-f0-9]{8}(-[a-f0-9]{4}){4}[a-f0-9]{8})")) {
-                target = Bukkit.getPlayer(UUID.fromString(args[1]));
-            }
-
-            if (target != null) {
-                if (target == controller) {
-                    controller.sendMessage(Component.text("You are already controlling yourself"));
-                } else if (PlayerList.getTarget(controller.getUniqueId()) != null) {
-                    controller.sendMessage(
-                        Component.text("You are already controlling \"")
-                            .append(Component.text(target.getName()))
-                            .append(Component.text("\""))
-                        );
-                } else if (PlayerList.getController(target.getUniqueId()) != null) {
-                    controller.sendMessage(
-                        Component.text("Player \"")
-                            .append(Component.text(target.getName()))
-                            .append(Component.text("\" is already being controlled"))
-                    );
-                } else if (PlayerList.getTarget(target.getUniqueId()) != null) {
-                    controller.sendMessage(
-                        Component.text("Player \"")
-                            .append(Component.text(target.getName()))
-                            .append(Component.text("\" is already controlling another player"))
-                    );
-                } else if (!controller.canSee(target)) {
-                    controller.sendMessage(Component.text("You may not control this player"));
-                } else {
-                    controller.teleportAsync(target.getLocation());
-
-                    controller.getInventory().setContents(target.getInventory().getContents());
-
-                    PlayerList.setTarget(controller.getUniqueId(), target);
-                    PlayerList.setController(target.getUniqueId(), controller);
-
-                    controller.sendMessage(
-                        Component.text("You are now controlling \"")
-                            .append(Component.text(target.getName()))
-                            .append(Component.text("\""))
-                    );
-                }
-            } else {
-                controller.sendMessage(
-                    Component.text("Player \"")
-                        .append(Component.text(args[1]))
-                        .append(Component.text("\" not found"))
-                );
-            }
+            return;
         }
+
+        Player target = Bukkit.getPlayer(args[1]);
+
+        if (target == null && args[1].matches("([a-f0-9]{8}(-[a-f0-9]{4}){4}[a-f0-9]{8})")) {
+            target = Bukkit.getPlayer(UUID.fromString(args[1]));
+        }
+
+        if (target == null) {
+            controller.sendMessage(
+                Component.text("Player \"")
+                    .append(Component.text(args[1]))
+                    .append(Component.text("\" not found"))
+            );
+            return;
+        }
+
+        if (target == controller) {
+            controller.sendMessage(Component.text("You are already controlling yourself"));
+            return;
+        }
+
+        if (PlayerControl.getTarget(controller.getUniqueId()) != null) {
+            controller.sendMessage(
+                Component.text("You are already controlling \"")
+                    .append(Component.text(target.getName()))
+                    .append(Component.text("\""))
+                );
+            return;
+        }
+
+        if (PlayerControl.getController(target.getUniqueId()) != null) {
+            controller.sendMessage(
+                Component.text("Player \"")
+                    .append(Component.text(target.getName()))
+                    .append(Component.text("\" is already being controlled"))
+            );
+            return;
+        }
+
+        if (PlayerControl.getTarget(target.getUniqueId()) != null) {
+            controller.sendMessage(
+                Component.text("Player \"")
+                    .append(Component.text(target.getName()))
+                    .append(Component.text("\" is already controlling another player"))
+            );
+            return;
+        }
+
+        if (!controller.canSee(target)) {
+            controller.sendMessage(Component.text("You may not control this player"));
+            return;
+        }
+
+        controller.teleportAsync(target.getLocation());
+        controller.getInventory().setContents(target.getInventory().getContents());
+
+        PlayerControl.setTarget(controller.getUniqueId(), target);
+        PlayerControl.setController(target.getUniqueId(), controller);
+
+        controller.sendMessage(
+            Component.text("You are now controlling \"")
+                .append(Component.text(target.getName()))
+                .append(Component.text("\""))
+        );
     }
 
     private void stopCommand(final Player controller) {
-        final Player target = PlayerList.getTarget(controller.getUniqueId());
+        final Player target = PlayerControl.getTarget(controller.getUniqueId());
 
-        if (target != null) {
-            PlayerList.removeTarget(controller.getUniqueId());
-            PlayerList.removeController(target.getUniqueId());
-
-            final int tickDelay = 200;
-
-            new BukkitRunnable() {
-                @Override
-                public void run() {
-                    for (Player player: Bukkit.getOnlinePlayers()) {
-                        player.showPlayer(JavaPlugin.getPlugin(Main.class), controller);
-                    }
-
-                    Scoreboard scoreboard = Bukkit.getScoreboardManager().getMainScoreboard();
-                    Team team = scoreboard.getTeam("icuCollision");
-                    if (team != null && team.hasEntry(controller.getName())) {
-                        team.removeEntry(controller.getName());
-                    }
-
-                    controller.removePotionEffect(PotionEffectType.INVISIBILITY);
-                    controller.sendMessage(Component.text("You are now visible"));
-                }
-            }.runTaskLater(JavaPlugin.getPlugin(Main.class), tickDelay);
-
-            final int seconds = tickDelay / 20;
-
-            controller.sendMessage(
-                Component.text("You are no longer controlling \"")
-                    .append(Component.text(target.getName()))
-                    .append(Component.text("\". You are invisible for "))
-                    .append(Component.text(seconds))
-                    .append(Component.text(" seconds."))
-            );
-        } else {
+        if (target == null) {
             controller.sendMessage(Component.text("You are not controlling anyone at the moment"));
+            return;
         }
+
+        PlayerControl.removeTarget(controller.getUniqueId());
+        PlayerControl.removeController(target.getUniqueId());
+        PlayerControl.scheduleVisibility(controller.getUniqueId());
+
+        controller.sendMessage(
+            Component.text("You are no longer controlling \"")
+                .append(Component.text(target.getName()))
+                .append(Component.text("\". You are invisible for "))
+                .append(Component.text(PlayerControl.getVisibilityDelay()))
+                .append(Component.text(" seconds."))
+        );
     }
 
     @Override
@@ -133,9 +126,15 @@ public final class CommandIcu implements CommandExecutor {
         if (args.length == 0) {
             controller.sendMessage(Component
                 .text("Usage: /" + label + " <control|stop>", NamedTextColor.RED));
-        } else if (args[0].equalsIgnoreCase("control")) {
+            return true;
+        }
+
+        if (args[0].equalsIgnoreCase("control")) {
             controlCommand(controller, label, args);
-        } else if (args[0].equalsIgnoreCase("stop")) {
+            return true;
+        }
+
+        if (args[0].equalsIgnoreCase("stop")) {
             stopCommand(controller);
         }
         return true;

src/main/java/pw/kaboom/icontrolu/modules/PlayerControl.java

@@ -0,0 +1,352 @@
+package pw.kaboom.icontrolu;
+
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.UUID;
+
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Entity;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.block.Action;
+import org.bukkit.event.entity.EntityDamageEvent;
+import org.bukkit.event.player.PlayerAnimationEvent;
+import org.bukkit.event.player.PlayerChatEvent;
+import org.bukkit.event.player.PlayerCommandPreprocessEvent;
+import org.bukkit.event.player.PlayerDropItemEvent;
+import org.bukkit.event.player.PlayerInteractEvent;
+import org.bukkit.event.player.PlayerMoveEvent;
+import org.bukkit.event.player.PlayerQuitEvent;
+import org.bukkit.event.player.PlayerRespawnEvent;
+import org.bukkit.inventory.EquipmentSlot;
+import org.bukkit.plugin.java.JavaPlugin;
+import org.bukkit.potion.PotionEffect;
+import org.bukkit.potion.PotionEffectType;
+import org.bukkit.scoreboard.Scoreboard;
+import org.bukkit.scoreboard.Team;
+
+import com.destroystokyo.paper.event.server.ServerTickStartEvent;
+
+import net.kyori.adventure.text.Component;
+
+public final class PlayerControl implements Listener {
+
+    private static final String CHAT_PREFIX = "\ud800iControlUChat\ud800";
+    private static final int VISIBILITY_DELAY_MS = 10000;
+
+    private static Map<UUID, Player> controllers = new HashMap<>();
+    private static Map<UUID, Player> targets = new HashMap<>();
+    private static Map<UUID, Long> scheduledVisibilities = new HashMap<>();
+
+    public static void enable() {
+        /* Setup scoreboard team to prevent player collisions */
+        final Scoreboard scoreboard = Bukkit.getScoreboardManager().getMainScoreboard();
+        final Team team = scoreboard.getTeam("icuCollision");
+        if (team != null) {
+            team.unregister();
+        }
+    }
+
+    public static void disable() {
+        for (UUID controllerUUID : targets.keySet()) {
+            final Player controller = Bukkit.getPlayer(controllerUUID);
+            final Player target = getTarget(controller.getUniqueId());
+
+            for (Player player: Bukkit.getOnlinePlayers()) {
+                player.showPlayer(JavaPlugin.getPlugin(Main.class), controller);
+            }
+
+            final Scoreboard scoreboard = Bukkit.getScoreboardManager().getMainScoreboard();
+            final Team team = scoreboard.getTeam("icuCollision");
+
+            if (team != null) {
+                team.unregister();
+            }
+
+            controller.removePotionEffect(PotionEffectType.INVISIBILITY);
+            controller.sendMessage(
+                Component.text("You are no longer controlling \"")
+                    .append(Component.text(target.getName()))
+                    .append(Component.text("\" due to server reload"))
+            );
+        }
+    }
+
+    public static Player getController(final UUID playerUUID) {
+        return controllers.get(playerUUID);
+    }
+
+    public static Player getTarget(final UUID playerUUID) {
+        return targets.get(playerUUID);
+    }
+
+    public static int getVisibilityDelay() {
+        return VISIBILITY_DELAY_MS / 1000;
+    }
+
+    public static void removeController(final UUID playerUUID) {
+        controllers.remove(playerUUID);
+    }
+
+    public static void removeTarget(final UUID playerUUID) {
+        targets.remove(playerUUID);
+    }
+
+    public static void setController(final UUID playerUUID, final Player player) {
+        controllers.put(playerUUID, player);
+    }
+
+    public static void setTarget(final UUID playerUUID, final Player player) {
+        targets.put(playerUUID, player);
+    }
+
+    public static void scheduleVisibility(final UUID playerUUID) {
+        scheduledVisibilities.put(playerUUID, System.currentTimeMillis() + VISIBILITY_DELAY_MS);
+    }
+
+    private void controlPlayers() {
+        if (targets.isEmpty()) {
+            return;
+        }
+
+        for (UUID controllerUUID : targets.keySet()) {
+            final Player controller = Bukkit.getPlayer(controllerUUID);
+            final Player target = getTarget(controllerUUID);
+
+            for (int i = 0; i < controller.getInventory().getSize(); i++) {
+                if (controller.getInventory().getItem(i) != null) {
+                    if (!controller.getInventory().getItem(i).equals(
+                            target.getInventory().getItem(i))) {
+                        target.getInventory().setItem(i, controller.getInventory().getItem(i));
+                    }
+                } else {
+                    target.getInventory().setItem(i, null);
+                }
+            }
+
+            if (target.getHealth() > 0) {
+                target.teleportAsync(controller.getLocation());
+            }
+
+            target.setAllowFlight(controller.getAllowFlight());
+            target.setExhaustion(controller.getExhaustion());
+            target.setFlying(controller.isFlying());
+            target.setFoodLevel(controller.getFoodLevel());
+
+            if (controller.getMaxHealth() > 0) {
+                target.setMaxHealth(controller.getMaxHealth());
+                target.setHealth(controller.getHealth());
+            }
+
+            target.setLevel(controller.getLevel());
+            target.setSneaking(controller.isSneaking());
+            target.setSprinting(controller.isSprinting());
+
+            for (Player player: Bukkit.getOnlinePlayers()) {
+                player.hidePlayer(JavaPlugin.getPlugin(Main.class), controller);
+            }
+
+            final Scoreboard scoreboard = Bukkit.getScoreboardManager().getMainScoreboard();
+            Team team = scoreboard.getTeam("icuCollision");
+
+            if (team == null) {
+                team = scoreboard.registerNewTeam("icuCollision");
+            }
+
+            team.setCanSeeFriendlyInvisibles(false);
+            team.setOption(Team.Option.COLLISION_RULE, Team.OptionStatus.NEVER);
+
+            if (!team.hasEntry(controller.getName())) {
+                team.addEntry(controller.getName());
+            }
+
+            final int duration = 99999;
+            final int amplifier = 0;
+            final boolean ambient = false;
+            final boolean particles = false;
+
+            controller.addPotionEffect(
+                new PotionEffect(
+                    PotionEffectType.INVISIBILITY,
+                    duration,
+                    amplifier,
+                    ambient,
+                    particles
+                )
+            );
+        }
+    }
+
+    private void checkVisibility() {
+        if (scheduledVisibilities.isEmpty()) {
+            return;
+        }
+
+        Iterator<Entry<UUID, Long>> iterator = scheduledVisibilities.entrySet().iterator();
+
+        while (iterator.hasNext()) {
+            final Entry<UUID, Long> entry = iterator.next();
+            final UUID playerUUID = entry.getKey();
+            long visibilityTime = entry.getValue();
+
+            if (System.currentTimeMillis() < visibilityTime) {
+                continue;
+            }
+
+            final Player controller = Bukkit.getPlayer(playerUUID);
+
+            for (Player onlinePlayer: Bukkit.getOnlinePlayers()) {
+                onlinePlayer.showPlayer(JavaPlugin.getPlugin(Main.class), controller);
+            }
+
+            final Scoreboard scoreboard = Bukkit.getScoreboardManager().getMainScoreboard();
+            final Team team = scoreboard.getTeam("icuCollision");
+
+            if (team != null && team.hasEntry(controller.getName())) {
+                team.removeEntry(controller.getName());
+            }
+
+            controller.removePotionEffect(PotionEffectType.INVISIBILITY);
+            controller.sendMessage(Component.text("You are now visible"));
+            iterator.remove();
+        }
+    }
+
+    @EventHandler
+    private void onEntityDamage(final EntityDamageEvent event) {
+        final Entity player = event.getEntity();
+
+        if (getTarget(player.getUniqueId()) != null) {
+            event.setCancelled(true);
+        }
+    }
+
+    @EventHandler
+    private void onPlayerAnimation(final PlayerAnimationEvent event) {
+        final Player player = event.getPlayer();
+
+        if (getController(player.getUniqueId()) != null) {
+            event.setCancelled(true);
+        }
+    }
+
+    @EventHandler
+    private void onPlayerChat(final PlayerChatEvent event) {
+        final Player player = event.getPlayer();
+        final UUID playerUUID = player.getUniqueId();
+
+        if (getController(playerUUID) != null) {
+            if (event.getMessage().startsWith(CHAT_PREFIX)) {
+                event.setMessage(event.getMessage().substring(CHAT_PREFIX.length()));
+                return;
+            }
+            event.setCancelled(true);
+            return;
+        }
+
+        final Player target = getTarget(playerUUID);
+
+        if (target != null) {
+            target.chat(CHAT_PREFIX + event.getMessage());
+            event.setCancelled(true);
+        }
+    }
+
+    @EventHandler
+    private void onPlayerCommandPreprocess(final PlayerCommandPreprocessEvent event) {
+        final Player player = event.getPlayer();
+
+        if (getController(player.getUniqueId()) != null) {
+            event.setCancelled(true);
+        }
+    }
+
+    @EventHandler
+    private void onPlayerDropItem(final PlayerDropItemEvent event) {
+        final Player player = event.getPlayer();
+
+        if (getController(player.getUniqueId()) != null) {
+            event.setCancelled(true);
+        }
+    }
+
+    @EventHandler
+    private void onPlayerInteract(final PlayerInteractEvent event) {
+        final Player player = event.getPlayer();
+
+        if (getController(player.getUniqueId()) != null) {
+            event.setCancelled(true);
+
+        } else if ((event.getAction() == Action.LEFT_CLICK_AIR
+                || event.getAction() == Action.LEFT_CLICK_BLOCK)
+                && getTarget(player.getUniqueId()) != null) {
+            final Player target = getTarget(player.getUniqueId());
+
+            if (event.getHand() == EquipmentSlot.HAND) {
+                target.swingMainHand();
+            } else if (event.getHand() == EquipmentSlot.OFF_HAND) {
+                target.swingOffHand();
+            }
+        }
+    }
+
+    @EventHandler
+    private void onPlayerMove(final PlayerMoveEvent event) {
+        final Player player = event.getPlayer();
+
+        if (getController(player.getUniqueId()) != null) {
+            event.setCancelled(true);
+        }
+    }
+
+    @EventHandler
+    private void onPlayerQuit(final PlayerQuitEvent event) {
+        final Player player = event.getPlayer();
+        final UUID playerUUID = player.getUniqueId();
+        final Player controller = getController(playerUUID);
+
+        if (controller != null) {
+            /*
+              Target disconnects
+              */
+            removeTarget(controller.getUniqueId());
+            removeController(playerUUID);
+            scheduleVisibility(controller.getUniqueId());
+
+            controller.sendMessage(Component.text("The player you were controlling has "
+                                   + "disconnected. You are invisible for 10 seconds."));
+            return;
+        }
+
+        final Player target = getTarget(playerUUID);
+
+        if (target != null) {
+            /*
+              Controller disconnects
+              */
+            removeTarget(playerUUID);
+            removeController(target.getUniqueId());
+        }
+    }
+
+    @EventHandler
+    private void onPlayerRespawn(final PlayerRespawnEvent event) {
+        final Player player = event.getPlayer();
+        final Player controller = getController(player.getUniqueId());
+
+        if (controller != null) {
+            controller.teleportAsync(player.getLocation());
+        }
+    }
+
+    @SuppressWarnings("deprecation")
+    @EventHandler(priority = EventPriority.MONITOR)
+    public void onTickStart(ServerTickStartEvent event) {
+        controlPlayers();
+        checkVisibility();
+    }
+}

src/main/java/pw/kaboom/icontrolu/utilities/PlayerList.java

@@ -1,38 +0,0 @@
-package pw.kaboom.icontrolu.utilities;
-
-import java.util.HashMap;
-import java.util.UUID;
-
-import org.bukkit.entity.Player;
-
-public final class PlayerList {
-    private PlayerList() {
-    }
-
-    private static HashMap<UUID, Player> controllerFor = new HashMap<UUID, Player>();
-    private static HashMap<UUID, Player> targetFor = new HashMap<UUID, Player>();
-
-    public static Player getController(final UUID playerUuid) {
-        return controllerFor.get(playerUuid);
-    }
-
-    public static Player getTarget(final UUID playerUuid) {
-        return targetFor.get(playerUuid);
-    }
-
-    public static void removeController(final UUID playerUuid) {
-        controllerFor.remove(playerUuid);
-    }
-
-    public static void removeTarget(final UUID playerUuid) {
-        targetFor.remove(playerUuid);
-    }
-
-    public static void setController(final UUID playerUuid, final Player player) {
-        controllerFor.put(playerUuid, player);
-    }
-
-    public static void setTarget(final UUID playerUuid, final Player player) {
-        targetFor.put(playerUuid, player);
-    }
-}