GH-878 Add vanish permission check for player tab suggestions (#878)

* Add vanish permission check for player tab suggestions

* Move `@FeatureDocs` annotation to PlayerArgument.

* Resolve issues raised during the discussion on Discord

Author: vLuckyyy

eternalcore-core/src/main/java/com/eternalcode/core/bridge/litecommand/argument/PlayerArgument.java

@@ -1,5 +1,7 @@
 package com.eternalcode.core.bridge.litecommand.argument;
 
+import com.eternalcode.annotations.scan.feature.FeatureDocs;
+import com.eternalcode.core.feature.vanish.VanishPermissionConstant;
 import com.eternalcode.core.feature.vanish.VanishService;
 import com.eternalcode.core.injector.annotations.Inject;
 import com.eternalcode.core.injector.annotations.lite.LiteArgument;
@@ -44,15 +46,25 @@ public ParseResult<Player> parse(Invocation<CommandSender> invocation, String ar
         return ParseResult.success(target);
     }
 
+    @FeatureDocs(
+        name = "Vanish tabulation",
+        description = "EternalCore prevents non-admin players from seeing vanished players in the commands like /tpa."
+            + " To re-enable this feature for specific players, grant them the eternalcore.vanish.tabulation.see permission."
+    )
     @Override
     public SuggestionResult suggest(
         Invocation<CommandSender> invocation,
         Argument<Player> argument,
         SuggestionContext context
     ) {
+        CommandSender sender = invocation.sender();
         return this.server.getOnlinePlayers().stream()
-            .filter(player -> !this.vanishService.isVanished(player.getUniqueId()))
-            .map(player -> player.getName())
+            .filter(player -> this.canSeeVanished(sender) || !this.vanishService.isVanished(player.getUniqueId()))
+            .map(Player::getName)
             .collect(SuggestionResult.collector());
     }
+
+    public boolean canSeeVanished(CommandSender sender) {
+        return sender.hasPermission(VanishPermissionConstant.VANISH_SEE_TABULATION_PERMISSION);
+    }
 }

eternalcore-core/src/main/java/com/eternalcode/core/feature/vanish/VanishPermissionConstant.java

@@ -0,0 +1,6 @@
+package com.eternalcode.core.feature.vanish;
+
+public class VanishPermissionConstant {
+
+    public static final String VANISH_SEE_TABULATION_PERMISSION = "eternalcore.vanish.tabulation.see";
+}

eternalcore-core/src/main/java/com/eternalcode/core/feature/vanish/VanishService.java

@@ -4,6 +4,7 @@
 import com.eternalcode.core.injector.annotations.component.Service;
 import java.util.UUID;
 import org.bukkit.Server;
+import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 import org.bukkit.metadata.MetadataValue;