Add option to use the servers uuid cache/lookup facility (#354)

common/src/main/java/me/lucko/luckperms/common/commands/abstraction/MainCommand.java

@@ -83,7 +83,7 @@ public abstract class MainCommand<T> extends Command<Void, T> {
             return CommandResult.INVALID_ARGS;
         }
 
-        final String name = args.get(0).toLowerCase();
+        final String name = args.get(0);
         T t = getTarget(name, plugin, sender);
         if (t != null) {
             CommandResult result;

common/src/main/java/me/lucko/luckperms/common/commands/impl/group/GroupMainCommand.java

@@ -65,6 +65,7 @@ public class GroupMainCommand extends MainCommand<Group> {
 
     @Override
     protected Group getTarget(String target, LuckPermsPlugin plugin, Sender sender) {
+        target = target.toLowerCase();
         if (!plugin.getStorage().loadGroup(target).join()) {
             Message.GROUP_NOT_FOUND.send(sender);
             return null;

common/src/main/java/me/lucko/luckperms/common/commands/impl/track/TrackMainCommand.java

@@ -55,6 +55,7 @@ public class TrackMainCommand extends MainCommand<Track> {
 
     @Override
     protected Track getTarget(String target, LuckPermsPlugin plugin, Sender sender) {
+        target = target.toLowerCase();
         if (!plugin.getStorage().loadTrack(target).join()) {
             Message.TRACK_NOT_FOUND.send(sender);
             return null;

common/src/main/java/me/lucko/luckperms/common/commands/impl/user/UserMainCommand.java

@@ -37,6 +37,7 @@ import me.lucko.luckperms.common.commands.impl.generic.parent.CommandParent;
 import me.lucko.luckperms.common.commands.impl.generic.permission.CommandPermission;
 import me.lucko.luckperms.common.commands.sender.Sender;
 import me.lucko.luckperms.common.commands.utils.Util;
+import me.lucko.luckperms.common.config.ConfigKeys;
 import me.lucko.luckperms.common.constants.DataConstraints;
 import me.lucko.luckperms.common.core.model.User;
 import me.lucko.luckperms.common.locale.CommandSpec;
@@ -66,26 +67,32 @@ public class UserMainCommand extends MainCommand<User> {
 
     @Override
     protected User getTarget(String target, LuckPermsPlugin plugin, Sender sender) {
-        UUID u = Util.parseUuid(target);
+        UUID u = Util.parseUuid(target.toLowerCase());
         if (u == null) {
-            if (target.length() <= 16) {
-                if (!DataConstraints.PLAYER_USERNAME_TEST.test(target)) {
-                    Message.USER_INVALID_ENTRY.send(sender, target);
+            if (!DataConstraints.PLAYER_USERNAME_TEST.test(target)) {
+                Message.USER_INVALID_ENTRY.send(sender, target);
+                return null;
+            }
+
+            u = plugin.getStorage().getUUID(target.toLowerCase()).join();
+            if (u == null) {
+                if (!plugin.getConfiguration().get(ConfigKeys.USE_SERVER_UUID_CACHE)) {
+                    Message.USER_NOT_FOUND.send(sender);
                     return null;
                 }
 
-                u = plugin.getStorage().getUUID(target).join();
+                u = plugin.lookupUuid(target).orElse(null);
                 if (u == null) {
                     Message.USER_NOT_FOUND.send(sender);
                     return null;
                 }
-            } else {
-                Message.USER_INVALID_ENTRY.send(sender, target);
             }
         }
 
         String name = plugin.getStorage().getName(u).join();
-        if (name == null) name = "null";
+        if (name == null) {
+            name = "null";
+        }
 
         if (!plugin.getStorage().loadUser(u, name).join()) {
             Message.LOADING_ERROR.send(sender);

common/src/main/java/me/lucko/luckperms/common/config/ConfigKeys.java

@@ -116,6 +116,11 @@ public class ConfigKeys {
         return c.contains("use-server-uuids") ? c.getBoolean("use-server-uuids", true) : c.getBoolean("online-mode", true);
     });
 
+    /**
+     * # If the servers own UUID cache/lookup facility should be used when there is no record for a player in the LuckPerms cache.
+     */
+    public static final ConfigKey<Boolean> USE_SERVER_UUID_CACHE = BooleanKey.of("use-server-uuid-cache", false);
+
     /**
      * Controls how temporary add commands should behave
      */

common/src/main/java/me/lucko/luckperms/common/plugin/LuckPermsPlugin.java

@@ -56,6 +56,7 @@ import java.io.InputStream;
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 import java.util.UUID;
 import java.util.function.Consumer;
@@ -285,6 +286,14 @@ public interface LuckPermsPlugin {
      */
     Object getPlayer(User user);
 
+    /**
+     * Lookup a uuid from a username, using the servers internal uuid cache.
+     *
+     * @param username the username to lookup
+     * @return an optional uuid, if found
+     */
+    Optional<UUID> lookupUuid(String username);
+
     /**
      * Gets a calculated context instance for the user using the rules of the platform.
      *