Refactoring + Fixes

13 files changed, 344 insertions, 213 deletions

diff --git a/src/main/java/net/elytrium/limboauth/LimboAuth.java b/src/main/java/net/elytrium/limboauth/LimboAuth.java
index f8e3755..1a3b6ca 100644
--- a/src/main/java/net/elytrium/limboauth/LimboAuth.java
+++ b/src/main/java/net/elytrium/limboauth/LimboAuth.java
@@ -65,6 +65,7 @@ import java.util.UUID;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
+import java.util.function.Function;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -97,7 +98,6 @@ import net.elytrium.limboauth.floodgate.FloodgateApiHolder;
 import net.elytrium.limboauth.handler.AuthSessionHandler;
 import net.elytrium.limboauth.listener.AuthListener;
 import net.elytrium.limboauth.model.RegisteredPlayer;
-import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.serializer.ComponentSerializer;
 import net.kyori.adventure.title.Title;
@@ -464,12 +464,12 @@ public class LimboAuth {
   public void cacheAuthUser(Player player) {
     String username = player.getUsername();
     String lowercaseUsername = username.toLowerCase(Locale.ROOT);
-    this.cachedAuthChecks.remove(lowercaseUsername);
     this.cachedAuthChecks.put(lowercaseUsername, new CachedSessionUser(System.currentTimeMillis(), player.getRemoteAddress().getAddress(), username));
   }
 
   public void removePlayerFromCache(String username) {
     this.cachedAuthChecks.remove(username.toLowerCase(Locale.ROOT));
+    this.premiumCache.remove(username.toLowerCase(Locale.ROOT));
   }
 
   public boolean needAuth(Player player) {
@@ -486,87 +486,88 @@ public class LimboAuth {
   public void authPlayer(Player player) {
     boolean isFloodgate = !Settings.IMP.MAIN.FLOODGATE_NEED_AUTH && this.floodgateApi.isFloodgatePlayer(player.getUniqueId());
     String nickname = player.getUsername();
-    if (this.nicknameValidationPattern.matcher((isFloodgate) ? nickname.substring(this.floodgateApi.getPrefixLength()) : nickname).matches()) {
-      RegisteredPlayer registeredPlayer = AuthSessionHandler.fetchInfo(this.playerDao, nickname);
+    if (!this.nicknameValidationPattern.matcher((isFloodgate) ? nickname.substring(this.floodgateApi.getPrefixLength()) : nickname).matches()) {
+      player.disconnect(this.nicknameInvalidKick);
+      return;
+    }
 
-      boolean onlineMode = player.isOnlineMode();
-      TaskEvent.Result result = TaskEvent.Result.NORMAL;
+    RegisteredPlayer registeredPlayer = AuthSessionHandler.fetchInfo(this.playerDao, nickname);
 
-      if (onlineMode || isFloodgate) {
-        if (registeredPlayer == null || registeredPlayer.getHash().isEmpty()) {
-          RegisteredPlayer nicknameRegisteredPlayer = registeredPlayer;
-          registeredPlayer = AuthSessionHandler.fetchInfo(this.playerDao, player.getUniqueId());
-
-          if (nicknameRegisteredPlayer != null && registeredPlayer == null && nicknameRegisteredPlayer.getHash().isEmpty()) {
-            registeredPlayer = nicknameRegisteredPlayer;
-            registeredPlayer.setPremiumUuid(player.getUniqueId().toString());
-            try {
-              this.playerDao.update(registeredPlayer);
-            } catch (SQLException e) {
-              e.printStackTrace();
-            }
+    boolean onlineMode = player.isOnlineMode();
+    TaskEvent.Result result = TaskEvent.Result.NORMAL;
+
+    if (onlineMode || isFloodgate) {
+      if (registeredPlayer == null || registeredPlayer.getHash().isEmpty()) {
+        RegisteredPlayer nicknameRegisteredPlayer = registeredPlayer;
+        registeredPlayer = AuthSessionHandler.fetchInfo(this.playerDao, player.getUniqueId());
+
+        if (nicknameRegisteredPlayer != null && registeredPlayer == null && nicknameRegisteredPlayer.getHash().isEmpty()) {
+          registeredPlayer = nicknameRegisteredPlayer;
+          registeredPlayer.setPremiumUuid(player.getUniqueId().toString());
+          try {
+            this.playerDao.update(registeredPlayer);
+          } catch (SQLException e) {
+            e.printStackTrace();
           }
+        }
 
-          if (nicknameRegisteredPlayer == null && registeredPlayer == null && Settings.IMP.MAIN.SAVE_PREMIUM_ACCOUNTS) {
-            registeredPlayer = new RegisteredPlayer(
-                nickname,
-                nickname.toLowerCase(Locale.ROOT),
-                "",
-                player.getRemoteAddress().getAddress().getHostAddress(),
-                "",
-                System.currentTimeMillis(),
-                player.getUniqueId().toString(),
-                player.getUniqueId().toString()
-            );
-
-            try {
-              this.playerDao.create(registeredPlayer);
-            } catch (SQLException e) {
-              e.printStackTrace();
-            }
+        if (nicknameRegisteredPlayer == null && registeredPlayer == null && Settings.IMP.MAIN.SAVE_PREMIUM_ACCOUNTS) {
+          registeredPlayer = new RegisteredPlayer(
+              nickname,
+              nickname.toLowerCase(Locale.ROOT),
+              "",
+              player.getRemoteAddress().getAddress().getHostAddress(),
+              "",
+              System.currentTimeMillis(),
+              player.getUniqueId().toString(),
+              player.getUniqueId().toString()
+          );
+
+          try {
+            this.playerDao.create(registeredPlayer);
+          } catch (SQLException e) {
+            e.printStackTrace();
           }
+        }
 
-          if (registeredPlayer == null || registeredPlayer.getHash().isEmpty()) {
-            // Due to the current connection state, which is set to LOGIN there, we cannot send the packets.
-            // We need to wait for the PLAY connection state to set.
-            this.postLoginTasks.put(player.getUniqueId(), () -> {
-              if (onlineMode) {
-                if (this.loginPremium != null) {
-                  player.sendMessage(this.loginPremium, MessageType.SYSTEM);
-                }
-                if (this.loginPremiumTitle != null) {
-                  player.showTitle(this.loginPremiumTitle);
-                }
-              } else {
-                if (this.loginFloodgate != null) {
-                  player.sendMessage(this.loginFloodgate, MessageType.SYSTEM);
-                }
-                if (this.loginFloodgateTitle != null) {
-                  player.showTitle(this.loginFloodgateTitle);
-                }
+        if (registeredPlayer == null || registeredPlayer.getHash().isEmpty()) {
+          // Due to the current connection state, which is set to LOGIN there, we cannot send the packets.
+          // We need to wait for the PLAY connection state to set.
+          this.postLoginTasks.put(player.getUniqueId(), () -> {
+            if (onlineMode) {
+              if (this.loginPremium != null) {
+                player.sendMessage(this.loginPremium);
+              }
+              if (this.loginPremiumTitle != null) {
+                player.showTitle(this.loginPremiumTitle);
+              }
+            } else {
+              if (this.loginFloodgate != null) {
+                player.sendMessage(this.loginFloodgate);
+              }
+              if (this.loginFloodgateTitle != null) {
+                player.showTitle(this.loginFloodgateTitle);
               }
-            });
+            }
+          });
 
-            result = TaskEvent.Result.BYPASS;
-          }
+          result = TaskEvent.Result.BYPASS;
         }
       }
+    }
 
-      EventManager eventManager = this.server.getEventManager();
-      if (registeredPlayer == null) {
-        if (Settings.IMP.MAIN.DISABLE_REGISTRATIONS) {
-          player.disconnect(this.registrationsDisabledKick);
-          return;
-        }
-
-        Consumer<TaskEvent> eventConsumer = (event) -> this.sendPlayer(event, null);
-        eventManager.fire(new PreRegisterEvent(eventConsumer, result, player)).thenAcceptAsync(eventConsumer);
-      } else {
-        Consumer<TaskEvent> eventConsumer = (event) -> this.sendPlayer(event, ((PreAuthorizationEvent) event).getPlayerInfo());
-        eventManager.fire(new PreAuthorizationEvent(eventConsumer, result, player, registeredPlayer)).thenAcceptAsync(eventConsumer);
+    EventManager eventManager = this.server.getEventManager();
+    if (registeredPlayer == null) {
+      if (Settings.IMP.MAIN.DISABLE_REGISTRATIONS) {
+        player.disconnect(this.registrationsDisabledKick);
+        return;
       }
+
+      Consumer<TaskEvent> eventConsumer = (event) -> this.sendPlayer(event, null);
+      eventManager.fire(new PreRegisterEvent(eventConsumer, result, player)).thenAcceptAsync(eventConsumer);
     } else {
-      player.disconnect(this.nicknameInvalidKick);
+      Consumer<TaskEvent> eventConsumer = (event) -> this.sendPlayer(event, ((PreAuthorizationEvent) event).getPlayerInfo());
+      eventManager.fire(new PreAuthorizationEvent(eventConsumer, result, player, registeredPlayer)).thenAcceptAsync(eventConsumer);
     }
   }
 
@@ -598,9 +599,8 @@ public class LimboAuth {
     }
   }
 
-  private boolean validateScheme(String json, List<String> scheme) {
+  private boolean validateScheme(JsonObject object, List<String> scheme) {
     if (!scheme.isEmpty()) {
-      JsonObject object = (JsonObject) JsonParser.parseString(json);
       for (String field : scheme) {
         if (!object.has(field)) {
           return false;
@@ -611,16 +611,11 @@ public class LimboAuth {
     return true;
   }
 
-  public boolean isPremiumExternal(String nickname) {
-    String lowercaseNickname = nickname.toLowerCase(Locale.ROOT);
-    if (this.premiumCache.containsKey(lowercaseNickname)) {
-      return this.premiumCache.get(lowercaseNickname).isPremium();
-    }
-
+  public PremiumResponse isPremiumExternal(String nickname) {
     try {
       HttpResponse<String> response = this.client.send(
           HttpRequest.newBuilder()
-              .uri(URI.create(String.format(Settings.IMP.MAIN.ISPREMIUM_AUTH_URL, URLEncoder.encode(lowercaseNickname, StandardCharsets.UTF_8))))
+              .uri(URI.create(String.format(Settings.IMP.MAIN.ISPREMIUM_AUTH_URL, URLEncoder.encode(nickname, StandardCharsets.UTF_8))))
               .build(),
           HttpResponse.BodyHandlers.ofString()
       );
@@ -628,59 +623,150 @@ public class LimboAuth {
       int statusCode = response.statusCode();
 
       if (statusCode == Settings.IMP.MAIN.STATUS_CODE_RATE_LIMIT) {
-        return Settings.IMP.MAIN.ON_RATE_LIMIT_PREMIUM;
+        return new PremiumResponse(PremiumState.RATE_LIMIT);
       }
 
+      JsonObject jsonObject = (JsonObject) JsonParser.parseString(response.body());
+
       if (statusCode == Settings.IMP.MAIN.STATUS_CODE_USER_EXISTS
-          && this.validateScheme(response.body(), Settings.IMP.MAIN.USER_EXISTS_JSON_VALIDATOR_FIELDS)) {
-        this.premiumCache.put(lowercaseNickname, new CachedPremiumUser(System.currentTimeMillis(), true));
-        return true;
+          && this.validateScheme(jsonObject, Settings.IMP.MAIN.USER_EXISTS_JSON_VALIDATOR_FIELDS)) {
+        return new PremiumResponse(PremiumState.PREMIUM, jsonObject.get(Settings.IMP.MAIN.JSON_UUID_FIELD).getAsString());
       }
 
       if (statusCode == Settings.IMP.MAIN.STATUS_CODE_USER_NOT_EXISTS
-          && this.validateScheme(response.body(), Settings.IMP.MAIN.USER_NOT_EXISTS_JSON_VALIDATOR_FIELDS)) {
-        this.premiumCache.put(lowercaseNickname, new CachedPremiumUser(System.currentTimeMillis(), false));
-        return false;
+          && this.validateScheme(jsonObject, Settings.IMP.MAIN.USER_NOT_EXISTS_JSON_VALIDATOR_FIELDS)) {
+        return new PremiumResponse(PremiumState.CRACKED);
       }
 
-      return Settings.IMP.MAIN.ON_SERVER_ERROR_PREMIUM;
+      return new PremiumResponse(PremiumState.ERROR);
     } catch (IOException | InterruptedException e) {
       LOGGER.error("Unable to authenticate with Mojang.", e);
+      return new PremiumResponse(PremiumState.ERROR);
+    }
+  }
+
+  public PremiumResponse isPremiumInternal(String nickname) {
+    try {
+      QueryBuilder<RegisteredPlayer, String> crackedCountQuery = this.playerDao.queryBuilder();
+      crackedCountQuery.where()
+          .eq(RegisteredPlayer.LOWERCASE_NICKNAME_FIELD, nickname)
+          .and()
+          .ne(RegisteredPlayer.HASH_FIELD, "");
+      crackedCountQuery.setCountOf(true);
+
+      QueryBuilder<RegisteredPlayer, String> premiumCountQuery = this.playerDao.queryBuilder();
+      premiumCountQuery.where()
+          .eq(RegisteredPlayer.LOWERCASE_NICKNAME_FIELD, nickname)
+          .and()
+          .eq(RegisteredPlayer.HASH_FIELD, "");
+      premiumCountQuery.setCountOf(true);
+
+      if (this.playerDao.countOf(crackedCountQuery.prepare()) != 0) {
+        return new PremiumResponse(PremiumState.CRACKED);
+      }
+
+      if (this.playerDao.countOf(premiumCountQuery.prepare()) != 0) {
+        return new PremiumResponse(PremiumState.PREMIUM);
+      }
+
+      return new PremiumResponse(PremiumState.UNKNOWN);
+    } catch (SQLException e) {
+      LOGGER.error("Unable to check if account is premium.", e);
+      return new PremiumResponse(PremiumState.ERROR);
+    }
+  }
+
+  public boolean isPremiumUuid(UUID uuid) {
+    try {
+      QueryBuilder<RegisteredPlayer, String> premiumCountQuery = this.playerDao.queryBuilder();
+      premiumCountQuery.where()
+          .eq(RegisteredPlayer.PREMIUM_UUID_FIELD, uuid.toString())
+          .and()
+          .eq(RegisteredPlayer.HASH_FIELD, "");
+      premiumCountQuery.setCountOf(true);
+
+      return this.playerDao.countOf(premiumCountQuery.prepare()) != 0;
+    } catch (SQLException e) {
+      LOGGER.error("Unable to check if account is premium.", e);
+      return false;
+    }
+  }
+
+  @SafeVarargs
+  private boolean checkIsPremiumAndCache(String nickname, Function<String, PremiumResponse>... functions) {
+    String lowercaseNickname = nickname.toLowerCase(Locale.ROOT);
+    if (this.premiumCache.containsKey(lowercaseNickname)) {
+      return this.premiumCache.get(lowercaseNickname).isPremium();
+    }
+
+    boolean premium = false;
+    boolean unknown = false;
+    boolean wasRateLimited = false;
+    boolean wasError = false;
+    UUID uuid = null;
+
+    for (Function<String, PremiumResponse> function : functions) {
+      PremiumResponse check = function.apply(lowercaseNickname);
+      if (check.getUuid() != null) {
+        uuid = check.getUuid();
+      }
+
+      switch (check.getState()) {
+        case CRACKED: {
+          this.premiumCache.put(lowercaseNickname, new CachedPremiumUser(System.currentTimeMillis(), false));
+          return false;
+        }
+        case PREMIUM: {
+          premium = true;
+          break;
+        }
+        case UNKNOWN: {
+          unknown = true;
+          break;
+        }
+        case RATE_LIMIT: {
+          wasRateLimited = true;
+          break;
+        }
+        default:
+        case ERROR: {
+          wasError = true;
+          break;
+        }
+      }
+    }
+
+    if (wasRateLimited && unknown || wasRateLimited && wasError) {
+      return Settings.IMP.MAIN.ON_RATE_LIMIT_PREMIUM;
+    }
+
+    if (wasError && unknown || !premium) {
       return Settings.IMP.MAIN.ON_SERVER_ERROR_PREMIUM;
     }
+
+    if (unknown) {
+      if (uuid != null && this.isPremiumUuid(uuid)) {
+        this.premiumCache.put(lowercaseNickname, new CachedPremiumUser(System.currentTimeMillis(), true));
+        return true;
+      }
+
+      if (Settings.IMP.MAIN.ONLINE_MODE_NEED_AUTH) {
+        return false;
+      }
+    }
+
+    this.premiumCache.put(lowercaseNickname, new CachedPremiumUser(System.currentTimeMillis(), true));
+    return true;
   }
 
   public boolean isPremium(String nickname) {
     if (Settings.IMP.MAIN.FORCE_OFFLINE_MODE) {
       return false;
     } else {
-      try {
-        if (this.isPremiumExternal(nickname)) {
-          QueryBuilder<RegisteredPlayer, String> premiumRegisteredQuery = this.playerDao.queryBuilder();
-          premiumRegisteredQuery.where()
-              .eq("LOWERCASENICKNAME", nickname.toLowerCase(Locale.ROOT))
-              .and()
-              .ne("HASH", "");
-          premiumRegisteredQuery.setCountOf(true);
-
-          QueryBuilder<RegisteredPlayer, String> premiumUnregisteredQuery = this.playerDao.queryBuilder();
-          premiumUnregisteredQuery.where()
-              .eq("LOWERCASENICKNAME", nickname.toLowerCase(Locale.ROOT))
-              .and()
-              .eq("HASH", "");
-          premiumUnregisteredQuery.setCountOf(true);
-
-          if (Settings.IMP.MAIN.ONLINE_MODE_NEED_AUTH) {
-            return this.playerDao.countOf(premiumRegisteredQuery.prepare()) == 0 && this.playerDao.countOf(premiumUnregisteredQuery.prepare()) != 0;
-          } else {
-            return this.playerDao.countOf(premiumRegisteredQuery.prepare()) == 0;
-          }
-        } else {
-          return false;
-        }
-      } catch (Exception e) {
-        LOGGER.error("Unable to authenticate with Mojang.", e);
-        return Settings.IMP.MAIN.ON_RATE_LIMIT_PREMIUM;
+      if (Settings.IMP.MAIN.CHECK_PREMIUM_PRIORITY_INTERNAL) {
+        return checkIsPremiumAndCache(nickname, this::isPremiumInternal, this::isPremiumExternal);
+      } else {
+        return checkIsPremiumAndCache(nickname, this::isPremiumExternal, this::isPremiumInternal);
       }
     }
   }
@@ -764,16 +850,57 @@ public class LimboAuth {
 
   private static class CachedPremiumUser extends CachedUser {
 
-    private final boolean isPremium;
+    private final boolean premium;
 
-    public CachedPremiumUser(long checkTime, boolean isPremium) {
+    public CachedPremiumUser(long checkTime, boolean premium) {
       super(checkTime);
 
-      this.isPremium = isPremium;
+      this.premium = premium;
     }
 
     public boolean isPremium() {
-      return this.isPremium;
+      return this.premium;
+    }
+  }
+
+  public static class PremiumResponse {
+
+    private final PremiumState state;
+    private final UUID uuid;
+
+    public PremiumResponse(PremiumState state) {
+      this.state = state;
+      this.uuid = null;
     }
+
+    public PremiumResponse(PremiumState state, UUID uuid) {
+      this.state = state;
+      this.uuid = uuid;
+    }
+
+    public PremiumResponse(PremiumState state, String uuid) {
+      this.state = state;
+      if (uuid.contains("-")) {
+        this.uuid = UUID.fromString(uuid);
+      } else {
+        this.uuid = new UUID(Long.parseUnsignedLong(uuid.substring(0, 16), 16), Long.parseUnsignedLong(uuid.substring(16), 16));
+      }
+    }
+
+    public PremiumState getState() {
+      return this.state;
+    }
+
+    public UUID getUuid() {
+      return this.uuid;
+    }
+  }
+
+  public enum PremiumState {
+    PREMIUM(),
+    CRACKED(),
+    UNKNOWN(),
+    RATE_LIMIT(),
+    ERROR()
   }
 }
diff --git a/src/main/java/net/elytrium/limboauth/Settings.java b/src/main/java/net/elytrium/limboauth/Settings.java
index 4a31e9a..f8733ad 100644
--- a/src/main/java/net/elytrium/limboauth/Settings.java
+++ b/src/main/java/net/elytrium/limboauth/Settings.java
@@ -66,6 +66,8 @@ public class Settings extends YamlConfig {
     public boolean FORCE_OFFLINE_MODE = false;
     @Comment("Forces all players to get offline uuid")
     public boolean FORCE_OFFLINE_UUID = false;
+    @Comment("If enabled, the plugin will firstly check whether the player is premium through the local database, and secondly through Mojang API.")
+    public boolean CHECK_PREMIUM_PRIORITY_INTERNAL = true;
     @Comment("Delay in milliseconds before sending auth-confirming titles and messages to the player. (login-premium-title, login-floodgate, etc.)")
     public int PREMIUM_AND_FLOODGATE_MESSAGES_DELAY = 1250;
     @Comment({
@@ -168,6 +170,7 @@ public class Settings extends YamlConfig {
         "Set this parameter to [], to disable JSON scheme validation"
     })
     public List<String> USER_EXISTS_JSON_VALIDATOR_FIELDS = List.of("name", "id");
+    public String JSON_UUID_FIELD = "id";
     public List<String> USER_NOT_EXISTS_JSON_VALIDATOR_FIELDS = List.of();
 
     @Comment({
diff --git a/src/main/java/net/elytrium/limboauth/command/ChangePasswordCommand.java b/src/main/java/net/elytrium/limboauth/command/ChangePasswordCommand.java
index 53280ec..c58448e 100644
--- a/src/main/java/net/elytrium/limboauth/command/ChangePasswordCommand.java
+++ b/src/main/java/net/elytrium/limboauth/command/ChangePasswordCommand.java
@@ -29,7 +29,6 @@ import net.elytrium.limboauth.LimboAuth;
 import net.elytrium.limboauth.Settings;
 import net.elytrium.limboauth.handler.AuthSessionHandler;
 import net.elytrium.limboauth.model.RegisteredPlayer;
-import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.text.Component;
 
 public class ChangePasswordCommand implements SimpleCommand {
@@ -69,32 +68,32 @@ public class ChangePasswordCommand implements SimpleCommand {
         if (this.needOldPass) {
           RegisteredPlayer player = AuthSessionHandler.fetchInfo(this.playerDao, ((Player) source).getUsername());
           if (player == null) {
-            source.sendMessage(this.notRegistered, MessageType.SYSTEM);
+            source.sendMessage(this.notRegistered);
             return;
           } else if (player.getHash().isEmpty()) {
-            source.sendMessage(this.crackedCommand, MessageType.SYSTEM);
+            source.sendMessage(this.crackedCommand);
           } else if (!AuthSessionHandler.checkPassword(args[0], player, this.playerDao)) {
-            source.sendMessage(this.wrongPassword, MessageType.SYSTEM);
+            source.sendMessage(this.wrongPassword);
             return;
           }
         }
 
         try {
           UpdateBuilder<RegisteredPlayer, String> updateBuilder = this.playerDao.updateBuilder();
-          updateBuilder.where().eq("NICKNAME", ((Player) source).getUsername());
-          updateBuilder.updateColumnValue("HASH", AuthSessionHandler.genHash(this.needOldPass ? args[1] : args[0]));
+          updateBuilder.where().eq(RegisteredPlayer.NICKNAME_FIELD, ((Player) source).getUsername());
+          updateBuilder.updateColumnValue(RegisteredPlayer.HASH_FIELD, AuthSessionHandler.genHash(this.needOldPass ? args[1] : args[0]));
           updateBuilder.update();
 
-          source.sendMessage(this.successful, MessageType.SYSTEM);
+          source.sendMessage(this.successful);
         } catch (SQLException e) {
-          source.sendMessage(this.errorOccurred, MessageType.SYSTEM);
+          source.sendMessage(this.errorOccurred);
           e.printStackTrace();
         }
       } else {
-        source.sendMessage(this.usage, MessageType.SYSTEM);
+        source.sendMessage(this.usage);
       }
     } else {
-      source.sendMessage(this.notPlayer, MessageType.SYSTEM);
+      source.sendMessage(this.notPlayer);
     }
   }
 
diff --git a/src/main/java/net/elytrium/limboauth/command/DestroySessionCommand.java b/src/main/java/net/elytrium/limboauth/command/DestroySessionCommand.java
index 53f460f..95e002c 100644
--- a/src/main/java/net/elytrium/limboauth/command/DestroySessionCommand.java
+++ b/src/main/java/net/elytrium/limboauth/command/DestroySessionCommand.java
@@ -24,7 +24,6 @@ import com.velocitypowered.api.proxy.Player;
 import net.elytrium.java.commons.mc.serialization.Serializer;
 import net.elytrium.limboauth.LimboAuth;
 import net.elytrium.limboauth.Settings;
-import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.text.Component;
 
 public class DestroySessionCommand implements SimpleCommand {
@@ -48,9 +47,9 @@ public class DestroySessionCommand implements SimpleCommand {
 
     if (source instanceof Player) {
       this.plugin.removePlayerFromCache(((Player) source).getUsername());
-      source.sendMessage(this.successful, MessageType.SYSTEM);
+      source.sendMessage(this.successful);
     } else {
-      source.sendMessage(this.notPlayer, MessageType.SYSTEM);
+      source.sendMessage(this.notPlayer);
     }
   }
 
diff --git a/src/main/java/net/elytrium/limboauth/command/ForceChangePasswordCommand.java b/src/main/java/net/elytrium/limboauth/command/ForceChangePasswordCommand.java
index 6704650..1186856 100644
--- a/src/main/java/net/elytrium/limboauth/command/ForceChangePasswordCommand.java
+++ b/src/main/java/net/elytrium/limboauth/command/ForceChangePasswordCommand.java
@@ -32,7 +32,6 @@ import net.elytrium.limboauth.LimboAuth;
 import net.elytrium.limboauth.Settings;
 import net.elytrium.limboauth.handler.AuthSessionHandler;
 import net.elytrium.limboauth.model.RegisteredPlayer;
-import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.text.Component;
 
 public class ForceChangePasswordCommand implements SimpleCommand {
@@ -72,20 +71,20 @@ public class ForceChangePasswordCommand implements SimpleCommand {
       Serializer serializer = LimboAuth.getSerializer();
       try {
         UpdateBuilder<RegisteredPlayer, String> updateBuilder = this.playerDao.updateBuilder();
-        updateBuilder.where().eq("LOWERCASENICKNAME", nickname.toLowerCase(Locale.ROOT));
-        updateBuilder.updateColumnValue("HASH", AuthSessionHandler.genHash(newPassword));
+        updateBuilder.where().eq(RegisteredPlayer.LOWERCASE_NICKNAME_FIELD, nickname.toLowerCase(Locale.ROOT));
+        updateBuilder.updateColumnValue(RegisteredPlayer.HASH_FIELD, AuthSessionHandler.genHash(newPassword));
         updateBuilder.update();
 
         this.server.getPlayer(nickname)
-            .ifPresent(player -> player.sendMessage(serializer.deserialize(MessageFormat.format(this.message, newPassword)), MessageType.SYSTEM));
+            .ifPresent(player -> player.sendMessage(serializer.deserialize(MessageFormat.format(this.message, newPassword))));
 
-        source.sendMessage(serializer.deserialize(MessageFormat.format(this.successful, nickname)), MessageType.SYSTEM);
+        source.sendMessage(serializer.deserialize(MessageFormat.format(this.successful, nickname)));
       } catch (SQLException e) {
-        source.sendMessage(serializer.deserialize(MessageFormat.format(this.notSuccessful, nickname)), MessageType.SYSTEM);
+        source.sendMessage(serializer.deserialize(MessageFormat.format(this.notSuccessful, nickname)));
         e.printStackTrace();
       }
     } else {
-      source.sendMessage(this.usage, MessageType.SYSTEM);
+      source.sendMessage(this.usage);
     }
   }
 
diff --git a/src/main/java/net/elytrium/limboauth/command/ForceUnregisterCommand.java b/src/main/java/net/elytrium/limboauth/command/ForceUnregisterCommand.java
index f065d25..2fd12ca 100644
--- a/src/main/java/net/elytrium/limboauth/command/ForceUnregisterCommand.java
+++ b/src/main/java/net/elytrium/limboauth/command/ForceUnregisterCommand.java
@@ -30,7 +30,6 @@ import net.elytrium.java.commons.mc.velocity.commands.SuggestUtils;
 import net.elytrium.limboauth.LimboAuth;
 import net.elytrium.limboauth.Settings;
 import net.elytrium.limboauth.model.RegisteredPlayer;
-import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.text.Component;
 
 public class ForceUnregisterCommand implements SimpleCommand {
@@ -74,13 +73,13 @@ public class ForceUnregisterCommand implements SimpleCommand {
         this.playerDao.deleteById(playerNick.toLowerCase(Locale.ROOT));
         this.plugin.removePlayerFromCache(playerNick);
         this.server.getPlayer(playerNick).ifPresent(player -> player.disconnect(this.kick));
-        source.sendMessage(serializer.deserialize(MessageFormat.format(this.successful, playerNick)), MessageType.SYSTEM);
+        source.sendMessage(serializer.deserialize(MessageFormat.format(this.successful, playerNick)));
       } catch (SQLException e) {
-        source.sendMessage(serializer.deserialize(MessageFormat.format(this.notSuccessful, playerNick)), MessageType.SYSTEM);
+        source.sendMessage(serializer.deserialize(MessageFormat.format(this.notSuccessful, playerNick)));
         e.printStackTrace();
       }
     } else {
-      source.sendMessage(this.usage, MessageType.SYSTEM);
+      source.sendMessage(this.usage);
     }
   }
 
diff --git a/src/main/java/net/elytrium/limboauth/command/LimboAuthCommand.java b/src/main/java/net/elytrium/limboauth/command/LimboAuthCommand.java
index ff31023..6d4a24c 100644
--- a/src/main/java/net/elytrium/limboauth/command/LimboAuthCommand.java
+++ b/src/main/java/net/elytrium/limboauth/command/LimboAuthCommand.java
@@ -26,7 +26,6 @@ import java.util.stream.Collectors;
 import net.elytrium.java.commons.mc.serialization.Serializer;
 import net.elytrium.limboauth.LimboAuth;
 import net.elytrium.limboauth.Settings;
-import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.format.NamedTextColor;
 
@@ -103,10 +102,10 @@ public class LimboAuthCommand implements SimpleCommand {
         if (command.equalsIgnoreCase("reload") && source.hasPermission("limboauth.admin.reload")) {
           try {
             this.plugin.reload();
-            source.sendMessage(serializer.deserialize(Settings.IMP.MAIN.STRINGS.RELOAD), MessageType.SYSTEM);
+            source.sendMessage(serializer.deserialize(Settings.IMP.MAIN.STRINGS.RELOAD));
           } catch (Exception e) {
             e.printStackTrace();
-            source.sendMessage(serializer.deserialize(Settings.IMP.MAIN.STRINGS.RELOAD_FAILED), MessageType.SYSTEM);
+            source.sendMessage(serializer.deserialize(Settings.IMP.MAIN.STRINGS.RELOAD_FAILED));
           }
 
           return;
@@ -144,16 +143,16 @@ public class LimboAuthCommand implements SimpleCommand {
 
   private void showHelp(CommandSource source) {
     for (Component component : HELP_MESSAGE) {
-      source.sendMessage(component, MessageType.SYSTEM);
+      source.sendMessage(component);
     }
     List<Map.Entry<String, Component>> availableSubcommands = SUBCOMMANDS.entrySet().stream()
         .filter(command -> source.hasPermission("limboauth.admin." + command.getKey()))
         .collect(Collectors.toList());
     if (availableSubcommands.size() > 0) {
-      source.sendMessage(AVAILABLE_SUBCOMMANDS_MESSAGE, MessageType.SYSTEM);
-      availableSubcommands.forEach(command -> source.sendMessage(command.getValue(), MessageType.SYSTEM));
+      source.sendMessage(AVAILABLE_SUBCOMMANDS_MESSAGE);
+      availableSubcommands.forEach(command -> source.sendMessage(command.getValue()));
     } else {
-      source.sendMessage(NO_AVAILABLE_SUBCOMMANDS_MESSAGE, MessageType.SYSTEM);
+      source.sendMessage(NO_AVAILABLE_SUBCOMMANDS_MESSAGE);
     }
   }
 }
diff --git a/src/main/java/net/elytrium/limboauth/command/PremiumCommand.java b/src/main/java/net/elytrium/limboauth/command/PremiumCommand.java
index cc73652..f4063d7 100644
--- a/src/main/java/net/elytrium/limboauth/command/PremiumCommand.java
+++ b/src/main/java/net/elytrium/limboauth/command/PremiumCommand.java
@@ -23,12 +23,12 @@ import com.velocitypowered.api.command.SimpleCommand;
 import com.velocitypowered.api.permission.Tristate;
 import com.velocitypowered.api.proxy.Player;
 import java.sql.SQLException;
+import java.util.Locale;
 import net.elytrium.java.commons.mc.serialization.Serializer;
 import net.elytrium.limboauth.LimboAuth;
 import net.elytrium.limboauth.Settings;
 import net.elytrium.limboauth.handler.AuthSessionHandler;
 import net.elytrium.limboauth.model.RegisteredPlayer;
-import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.text.Component;
 
 public class PremiumCommand implements SimpleCommand {
@@ -73,34 +73,34 @@ public class PremiumCommand implements SimpleCommand {
           String username = ((Player) source).getUsername();
           RegisteredPlayer player = AuthSessionHandler.fetchInfo(this.playerDao, username);
           if (player == null) {
-            source.sendMessage(this.notRegistered, MessageType.SYSTEM);
+            source.sendMessage(this.notRegistered);
           } else if (player.getHash().isEmpty()) {
-            source.sendMessage(this.alreadyPremium, MessageType.SYSTEM);
+            source.sendMessage(this.alreadyPremium);
           } else if (AuthSessionHandler.checkPassword(args[0], player, this.playerDao)) {
-            if (this.plugin.isPremiumExternal(username)) {
+            if (this.plugin.isPremiumExternal(username.toLowerCase(Locale.ROOT)).getState() == LimboAuth.PremiumState.PREMIUM) {
               try {
                 player.setHash("");
                 this.playerDao.update(player);
                 this.plugin.removePlayerFromCache(username);
                 ((Player) source).disconnect(this.successful);
               } catch (SQLException e) {
-                source.sendMessage(this.errorOccurred, MessageType.SYSTEM);
+                source.sendMessage(this.errorOccurred);
                 e.printStackTrace();
               }
             } else {
-              source.sendMessage(this.notPremium, MessageType.SYSTEM);
+              source.sendMessage(this.notPremium);
             }
           } else {
-            source.sendMessage(this.wrongPassword, MessageType.SYSTEM);
+            source.sendMessage(this.wrongPassword);
           }
 
           return;
         }
       }
 
-      source.sendMessage(this.usage, MessageType.SYSTEM);
+      source.sendMessage(this.usage);
     } else {
-      source.sendMessage(this.notPlayer, MessageType.SYSTEM);
+      source.sendMessage(this.notPlayer);
     }
   }
 
diff --git a/src/main/java/net/elytrium/limboauth/command/TotpCommand.java b/src/main/java/net/elytrium/limboauth/command/TotpCommand.java
index 7609020..0ad71f5 100644
--- a/src/main/java/net/elytrium/limboauth/command/TotpCommand.java
+++ b/src/main/java/net/elytrium/limboauth/command/TotpCommand.java
@@ -36,7 +36,6 @@ import net.elytrium.limboauth.LimboAuth;
 import net.elytrium.limboauth.Settings;
 import net.elytrium.limboauth.handler.AuthSessionHandler;
 import net.elytrium.limboauth.model.RegisteredPlayer;
-import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.event.ClickEvent;
 
@@ -95,7 +94,7 @@ public class TotpCommand implements SimpleCommand {
 
     if (source instanceof Player) {
       if (args.length == 0) {
-        source.sendMessage(this.usage, MessageType.SYSTEM);
+        source.sendMessage(this.usage);
       } else {
         String username = ((Player) source).getUsername();
 
@@ -105,32 +104,32 @@ public class TotpCommand implements SimpleCommand {
           if (this.needPassword ? args.length == 2 : args.length == 1) {
             playerInfo = AuthSessionHandler.fetchInfo(this.playerDao, username);
             if (playerInfo == null) {
-              source.sendMessage(this.notRegistered, MessageType.SYSTEM);
+              source.sendMessage(this.notRegistered);
               return;
             } else if (playerInfo.getHash().isEmpty()) {
-              source.sendMessage(this.crackedCommand, MessageType.SYSTEM);
+              source.sendMessage(this.crackedCommand);
               return;
             } else if (this.needPassword && !AuthSessionHandler.checkPassword(args[1], playerInfo, this.playerDao)) {
-              source.sendMessage(this.wrongPassword, MessageType.SYSTEM);
+              source.sendMessage(this.wrongPassword);
               return;
             }
 
             if (!playerInfo.getTotpToken().isEmpty()) {
-              source.sendMessage(this.alreadyEnabled, MessageType.SYSTEM);
+              source.sendMessage(this.alreadyEnabled);
               return;
             }
 
             String secret = this.secretGenerator.generate();
             try {
               updateBuilder = this.playerDao.updateBuilder();
-              updateBuilder.where().eq("NICKNAME", username);
-              updateBuilder.updateColumnValue("TOTPTOKEN", secret);
+              updateBuilder.where().eq(RegisteredPlayer.NICKNAME_FIELD, username);
+              updateBuilder.updateColumnValue(RegisteredPlayer.TOTP_TOKEN_FIELD, secret);
               updateBuilder.update();
             } catch (SQLException e) {
-              source.sendMessage(this.errorOccurred, MessageType.SYSTEM);
+              source.sendMessage(this.errorOccurred);
               e.printStackTrace();
             }
-            source.sendMessage(this.successful, MessageType.SYSTEM);
+            source.sendMessage(this.successful);
 
             QrData data = new QrData.Builder()
                 .label(username)
@@ -138,50 +137,50 @@ public class TotpCommand implements SimpleCommand {
                 .issuer(this.issuer)
                 .build();
             String qrUrl = this.qrGeneratorUrl.replace("{data}", URLEncoder.encode(data.getUri(), StandardCharsets.UTF_8));
-            source.sendMessage(this.qr.clickEvent(ClickEvent.openUrl(qrUrl)), MessageType.SYSTEM);
+            source.sendMessage(this.qr.clickEvent(ClickEvent.openUrl(qrUrl)));
 
             Serializer serializer = LimboAuth.getSerializer();
             source.sendMessage(serializer.deserialize(MessageFormat.format(this.token, secret))
-                .clickEvent(ClickEvent.copyToClipboard(secret)), MessageType.SYSTEM);
+                .clickEvent(ClickEvent.copyToClipboard(secret)));
             String codes = String.join(", ", this.codesGenerator.generateCodes(this.recoveryCodesAmount));
             source.sendMessage(serializer.deserialize(MessageFormat.format(this.recovery, codes))
-                .clickEvent(ClickEvent.copyToClipboard(codes)), MessageType.SYSTEM);
+                .clickEvent(ClickEvent.copyToClipboard(codes)));
           } else {
-            source.sendMessage(this.usage, MessageType.SYSTEM);
+            source.sendMessage(this.usage);
           }
         } else if (args[0].equalsIgnoreCase("disable")) {
           if (args.length == 2) {
             playerInfo = AuthSessionHandler.fetchInfo(this.playerDao, username);
 
             if (playerInfo == null) {
-              source.sendMessage(this.notRegistered, MessageType.SYSTEM);
+              source.sendMessage(this.notRegistered);
               return;
             }
 
             if (AuthSessionHandler.getTotpCodeVerifier().isValidCode(playerInfo.getTotpToken(), args[1])) {
               try {
                 updateBuilder = this.playerDao.updateBuilder();
-                updateBuilder.where().eq("NICKNAME", username);
-                updateBuilder.updateColumnValue("TOTPTOKEN", "");
+                updateBuilder.where().eq(RegisteredPlayer.NICKNAME_FIELD, username);
+                updateBuilder.updateColumnValue(RegisteredPlayer.TOTP_TOKEN_FIELD, "");
                 updateBuilder.update();
 
-                source.sendMessage(this.disabled, MessageType.SYSTEM);
+                source.sendMessage(this.disabled);
               } catch (SQLException e) {
-                source.sendMessage(this.errorOccurred, MessageType.SYSTEM);
+                source.sendMessage(this.errorOccurred);
                 e.printStackTrace();
               }
             } else {
-              source.sendMessage(this.wrong, MessageType.SYSTEM);
+              source.sendMessage(this.wrong);
             }
           } else {
-            source.sendMessage(this.usage, MessageType.SYSTEM);
+            source.sendMessage(this.usage);
           }
         } else {
-          source.sendMessage(this.usage, MessageType.SYSTEM);
+          source.sendMessage(this.usage);
         }
       }
     } else {
-      source.sendMessage(this.notPlayer, MessageType.SYSTEM);
+      source.sendMessage(this.notPlayer);
     }
   }
 
diff --git a/src/main/java/net/elytrium/limboauth/command/UnregisterCommand.java b/src/main/java/net/elytrium/limboauth/command/UnregisterCommand.java
index b5ab2a0..b6c11ff 100644
--- a/src/main/java/net/elytrium/limboauth/command/UnregisterCommand.java
+++ b/src/main/java/net/elytrium/limboauth/command/UnregisterCommand.java
@@ -30,7 +30,6 @@ import net.elytrium.limboauth.Settings;
 import net.elytrium.limboauth.event.AuthUnregisterEvent;
 import net.elytrium.limboauth.handler.AuthSessionHandler;
 import net.elytrium.limboauth.model.RegisteredPlayer;
-import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.text.Component;
 
 public class UnregisterCommand implements SimpleCommand {
@@ -73,9 +72,9 @@ public class UnregisterCommand implements SimpleCommand {
           String username = ((Player) source).getUsername();
           RegisteredPlayer player = AuthSessionHandler.fetchInfo(this.playerDao, username);
           if (player == null) {
-            source.sendMessage(this.notRegistered, MessageType.SYSTEM);
+            source.sendMessage(this.notRegistered);
           } else if (player.getHash().isEmpty()) {
-            source.sendMessage(this.crackedCommand, MessageType.SYSTEM);
+            source.sendMessage(this.crackedCommand);
           } else if (AuthSessionHandler.checkPassword(args[0], player, this.playerDao)) {
             try {
               this.plugin.getServer().getEventManager().fireAndForget(new AuthUnregisterEvent(username));
@@ -83,20 +82,20 @@ public class UnregisterCommand implements SimpleCommand {
               this.plugin.removePlayerFromCache(username);
               ((Player) source).disconnect(this.successful);
             } catch (SQLException e) {
-              source.sendMessage(this.errorOccurred, MessageType.SYSTEM);
+              source.sendMessage(this.errorOccurred);
               e.printStackTrace();
             }
           } else {
-            source.sendMessage(this.wrongPassword, MessageType.SYSTEM);
+            source.sendMessage(this.wrongPassword);
           }
 
           return;
         }
       }
 
-      source.sendMessage(this.usage, MessageType.SYSTEM);
+      source.sendMessage(this.usage);
     } else {
-      source.sendMessage(this.notPlayer, MessageType.SYSTEM);
+      source.sendMessage(this.notPlayer);
     }
   }
 
diff --git a/src/main/java/net/elytrium/limboauth/handler/AuthSessionHandler.java b/src/main/java/net/elytrium/limboauth/handler/AuthSessionHandler.java
index 6f4b27e..c8e8f89 100644
--- a/src/main/java/net/elytrium/limboauth/handler/AuthSessionHandler.java
+++ b/src/main/java/net/elytrium/limboauth/handler/AuthSessionHandler.java
@@ -44,7 +44,6 @@ import net.elytrium.limboauth.event.PostRegisterEvent;
 import net.elytrium.limboauth.event.TaskEvent;
 import net.elytrium.limboauth.migration.MigrationHash;
 import net.elytrium.limboauth.model.RegisteredPlayer;
-import net.kyori.adventure.audience.MessageType;
 import net.kyori.adventure.bossbar.BossBar;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.title.Title;
@@ -126,7 +125,7 @@ public class AuthSessionHandler implements LimboSessionHandler {
 
     if (this.playerInfo == null) {
       try {
-        List<RegisteredPlayer> alreadyRegistered = this.playerDao.queryForEq("IP", this.ip);
+        List<RegisteredPlayer> alreadyRegistered = this.playerDao.queryForEq(RegisteredPlayer.IP_FIELD, this.ip);
         if (alreadyRegistered != null) {
           int sizeOfValidRegistrations = alreadyRegistered.size();
           if (Settings.IMP.MAIN.IP_LIMIT_VALID_TIME > 0) {
@@ -208,7 +207,7 @@ public class AuthSessionHandler implements LimboSessionHandler {
             this.proxyPlayer.disconnect(databaseErrorKick);
           }
 
-          this.proxyPlayer.sendMessage(registerSuccessful, MessageType.SYSTEM);
+          this.proxyPlayer.sendMessage(registerSuccessful);
           if (registerSuccessfulTitle != null) {
             this.proxyPlayer.showTitle(registerSuccessfulTitle);
           }
@@ -232,7 +231,7 @@ public class AuthSessionHandler implements LimboSessionHandler {
             this.sendMessage(true);
           }
         } else if (--this.attempts != 0) {
-          this.proxyPlayer.sendMessage(loginWrongPassword[this.attempts - 1], MessageType.SYSTEM);
+          this.proxyPlayer.sendMessage(loginWrongPassword[this.attempts - 1]);
         } else {
           this.proxyPlayer.disconnect(loginWrongPasswordKick);
         }
@@ -260,17 +259,17 @@ public class AuthSessionHandler implements LimboSessionHandler {
 
   private void sendMessage(boolean sendTitle) {
     if (this.totpState) {
-      this.proxyPlayer.sendMessage(totp, MessageType.SYSTEM);
+      this.proxyPlayer.sendMessage(totp);
       if (sendTitle && totpTitle != null) {
         this.proxyPlayer.showTitle(totpTitle);
       }
     } else if (this.playerInfo == null) {
-      this.proxyPlayer.sendMessage(register, MessageType.SYSTEM);
+      this.proxyPlayer.sendMessage(register);
       if (sendTitle && registerTitle != null) {
         this.proxyPlayer.showTitle(registerTitle);
       }
     } else {
-      this.proxyPlayer.sendMessage(login[this.attempts - 1], MessageType.SYSTEM);
+      this.proxyPlayer.sendMessage(login[this.attempts - 1]);
       if (sendTitle && loginTitle != null) {
         this.proxyPlayer.showTitle(loginTitle);
       }
@@ -289,7 +288,7 @@ public class AuthSessionHandler implements LimboSessionHandler {
     if (!Settings.IMP.MAIN.REGISTER_NEED_REPEAT_PASSWORD || args[1].equals(args[2])) {
       return true;
     } else {
-      this.proxyPlayer.sendMessage(registerDifferentPasswords, MessageType.SYSTEM);
+      this.proxyPlayer.sendMessage(registerDifferentPasswords);
       return false;
     }
   }
@@ -297,10 +296,10 @@ public class AuthSessionHandler implements LimboSessionHandler {
   private boolean checkPasswordLength(String password) {
     int length = password.length();
     if (length > Settings.IMP.MAIN.MAX_PASSWORD_LENGTH) {
-      this.proxyPlayer.sendMessage(registerPasswordTooLong, MessageType.SYSTEM);
+      this.proxyPlayer.sendMessage(registerPasswordTooLong);
       return false;
     } else if (length < Settings.IMP.MAIN.MIN_PASSWORD_LENGTH) {
-      this.proxyPlayer.sendMessage(registerPasswordTooShort, MessageType.SYSTEM);
+      this.proxyPlayer.sendMessage(registerPasswordTooShort);
       return false;
     } else {
       return true;
@@ -309,7 +308,7 @@ public class AuthSessionHandler implements LimboSessionHandler {
 
   private boolean checkPasswordStrength(String password) {
     if (Settings.IMP.MAIN.CHECK_PASSWORD_STRENGTH && this.plugin.getUnsafePasswords().contains(password)) {
-      this.proxyPlayer.sendMessage(registerPasswordUnsafe, MessageType.SYSTEM);
+      this.proxyPlayer.sendMessage(registerPasswordUnsafe);
       return false;
     } else {
       return true;
@@ -317,7 +316,7 @@ public class AuthSessionHandler implements LimboSessionHandler {
   }
 
   private void finishLogin() {
-    this.proxyPlayer.sendMessage(loginSuccessful, MessageType.SYSTEM);
+    this.proxyPlayer.sendMessage(loginSuccessful);
     if (loginSuccessfulTitle != null) {
       this.proxyPlayer.showTitle(loginSuccessfulTitle);
     }
@@ -447,7 +446,7 @@ public class AuthSessionHandler implements LimboSessionHandler {
   public static RegisteredPlayer fetchInfo(Dao<RegisteredPlayer, String> playerDao, UUID uuid) {
     List<RegisteredPlayer> playerList = null;
     try {
-      playerList = playerDao.queryForEq("PREMIUMUUID", uuid.toString());
+      playerList = playerDao.queryForEq(RegisteredPlayer.PREMIUM_UUID_FIELD, uuid.toString());
     } catch (SQLException e) {
       e.printStackTrace();
     }
@@ -458,7 +457,7 @@ public class AuthSessionHandler implements LimboSessionHandler {
   public static RegisteredPlayer fetchInfo(Dao<RegisteredPlayer, String> playerDao, String nickname) {
     List<RegisteredPlayer> playerList = null;
     try {
-      playerList = playerDao.queryForEq("LOWERCASENICKNAME", nickname.toLowerCase(Locale.ROOT));
+      playerList = playerDao.queryForEq(RegisteredPlayer.LOWERCASE_NICKNAME_FIELD, nickname.toLowerCase(Locale.ROOT));
     } catch (SQLException e) {
       e.printStackTrace();
     }
diff --git a/src/main/java/net/elytrium/limboauth/listener/AuthListener.java b/src/main/java/net/elytrium/limboauth/listener/AuthListener.java
index 2529e80..a96a88d 100644
--- a/src/main/java/net/elytrium/limboauth/listener/AuthListener.java
+++ b/src/main/java/net/elytrium/limboauth/listener/AuthListener.java
@@ -76,7 +76,7 @@ public class AuthListener {
   @Subscribe
   public void onLoginLimboRegister(LoginLimboRegisterEvent event) {
     if (this.plugin.needAuth(event.getPlayer())) {
-      event.addCallback(() -> this.plugin.authPlayer(event.getPlayer()));
+      event.addOnJoinCallback(() -> this.plugin.authPlayer(event.getPlayer()));
     }
   }
 
@@ -109,8 +109,8 @@ public class AuthListener {
     } else if (event.isOnlineMode()) {
       try {
         UpdateBuilder<RegisteredPlayer, String> updateBuilder = this.playerDao.updateBuilder();
-        updateBuilder.where().eq("NICKNAME", event.getUsername());
-        updateBuilder.updateColumnValue("HASH", "");
+        updateBuilder.where().eq(RegisteredPlayer.NICKNAME_FIELD, event.getUsername());
+        updateBuilder.updateColumnValue(RegisteredPlayer.HASH_FIELD, "");
         updateBuilder.update();
       } catch (SQLException e) {
         e.printStackTrace();
diff --git a/src/main/java/net/elytrium/limboauth/model/RegisteredPlayer.java b/src/main/java/net/elytrium/limboauth/model/RegisteredPlayer.java
index b54f9b8..4827d92 100644
--- a/src/main/java/net/elytrium/limboauth/model/RegisteredPlayer.java
+++ b/src/main/java/net/elytrium/limboauth/model/RegisteredPlayer.java
@@ -23,28 +23,37 @@ import com.j256.ormlite.table.DatabaseTable;
 @DatabaseTable(tableName = "AUTH")
 public class RegisteredPlayer {
 
-  @DatabaseField(canBeNull = false, columnName = "NICKNAME")
+  public static final String NICKNAME_FIELD = "NICKNAME";
+  public static final String LOWERCASE_NICKNAME_FIELD = "LOWERCASENICKNAME";
+  public static final String HASH_FIELD = "HASH";
+  public static final String IP_FIELD = "IP";
+  public static final String TOTP_TOKEN_FIELD = "TOTPTOKEN";
+  public static final String REG_DATE_FIELD = "REGDATE";
+  public static final String UUID_FIELD = "UUID";
+  public static final String PREMIUM_UUID_FIELD = "PREMIUMUUID";
+
+  @DatabaseField(canBeNull = false, columnName = NICKNAME_FIELD)
   private String nickname;
 
-  @DatabaseField(id = true, columnName = "LOWERCASENICKNAME")
+  @DatabaseField(id = true, columnName = LOWERCASE_NICKNAME_FIELD)
   private String lowercaseNickname;
 
-  @DatabaseField(canBeNull = false, columnName = "HASH")
+  @DatabaseField(canBeNull = false, columnName = HASH_FIELD)
   private String hash;
 
-  @DatabaseField(columnName = "IP")
+  @DatabaseField(columnName = IP_FIELD)
   private String ip;
 
-  @DatabaseField(columnName = "TOTPTOKEN")
+  @DatabaseField(columnName = TOTP_TOKEN_FIELD)
   private String totpToken;
 
-  @DatabaseField(columnName = "REGDATE")
+  @DatabaseField(columnName = REG_DATE_FIELD)
   private Long regDate;
 
-  @DatabaseField(columnName = "UUID")
+  @DatabaseField(columnName = UUID_FIELD)
   private String uuid;
 
-  @DatabaseField(columnName = "PREMIUMUUID")
+  @DatabaseField(columnName = RegisteredPlayer.PREMIUM_UUID_FIELD)
   private String premiumUuid;
 
   public RegisteredPlayer(String nickname, String lowercaseNickname,