Fixed compatibility with the latest Velocity dev builds

Co-authored-by: Camotoy <20743703+camotoy@users.noreply.github.com>

common/src/main/java/org/geysermc/floodgate/util/ReflectionUtils.java

@@ -59,6 +59,15 @@ public final class ReflectionUtils {
         return getClass(prefix + "." + className);
     }
 
+    @Nullable
+    public static Class<?> getPrefixedClassSilently(String className) {
+        try {
+            return Class.forName(prefix + "." + className);
+        } catch (ClassNotFoundException ignored) {
+            return null;
+        }
+    }
+
     /**
      * Get the class from a class name. Calling this method is equal to calling {@link
      * Class#forName(String)} where String is the class name.<br> This method will return null when
@@ -485,7 +494,9 @@ public final class ReflectionUtils {
      * @return the accessibleObject
      */
     public static <T extends AccessibleObject> T makeAccessible(T accessibleObject) {
+        if (!accessibleObject.isAccessible()) {
             accessibleObject.setAccessible(true);
+        }
         return accessibleObject;
     }
 }

velocity/src/main/java/org/geysermc/floodgate/addon/data/VelocityProxyDataHandler.java

@@ -95,7 +95,7 @@ public final class VelocityProxyDataHandler extends CommonDataHandler {
             logger.info("Floodgate player who is logged in as {} {} joined",
                     player.getCorrectUsername(), player.getCorrectUniqueId());
         }
-        return true;
+        return super.shouldRemoveHandler(result);
     }
 
     @Override

velocity/src/main/java/org/geysermc/floodgate/listener/VelocityListener.java

@@ -26,8 +26,10 @@
 package org.geysermc.floodgate.listener;
 
 import static org.geysermc.floodgate.util.ReflectionUtils.getCastedValue;
+import static org.geysermc.floodgate.util.ReflectionUtils.getField;
 import static org.geysermc.floodgate.util.ReflectionUtils.getFieldOfType;
 import static org.geysermc.floodgate.util.ReflectionUtils.getPrefixedClass;
+import static org.geysermc.floodgate.util.ReflectionUtils.getPrefixedClassSilently;
 import static org.geysermc.floodgate.util.ReflectionUtils.getValue;
 
 import com.google.common.cache.Cache;
@@ -46,6 +48,7 @@ import io.netty.channel.Channel;
 import io.netty.util.AttributeKey;
 import java.lang.reflect.Field;
 import java.util.ArrayList;
+import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 import net.kyori.adventure.text.Component;
 import org.geysermc.floodgate.api.ProxyFloodgateApi;
@@ -56,13 +59,27 @@ import org.geysermc.floodgate.util.VelocityCommandUtil;
 
 public final class VelocityListener {
     private static final Field INITIAL_MINECRAFT_CONNECTION;
+    private static final Field INITIAL_CONNECTION_DELEGATE;
     private static final Field CHANNEL;
 
     static {
         Class<?> initialConnection = getPrefixedClass("connection.client.InitialInboundConnection");
-
         Class<?> minecraftConnection = getPrefixedClass("connection.MinecraftConnection");
         INITIAL_MINECRAFT_CONNECTION = getFieldOfType(initialConnection, minecraftConnection);
+
+        // Since Velocity 3.1.0
+        Class<?> loginInboundConnection =
+                getPrefixedClassSilently("connection.client.LoginInboundConnection");
+        if (loginInboundConnection != null) {
+            INITIAL_CONNECTION_DELEGATE = getField(loginInboundConnection, "delegate");
+            Objects.requireNonNull(
+                    INITIAL_CONNECTION_DELEGATE,
+                    "initial inbound connection delegate cannot be null"
+            );
+        } else {
+            INITIAL_CONNECTION_DELEGATE = null;
+        }
+
         CHANNEL = getFieldOfType(minecraftConnection, Channel.class);
     }
 
@@ -89,7 +106,14 @@ public final class VelocityListener {
         FloodgatePlayer player = null;
         String kickMessage;
         try {
-            Object mcConnection = getValue(event.getConnection(), INITIAL_MINECRAFT_CONNECTION);
+            InboundConnection connection = event.getConnection();
+            if (INITIAL_CONNECTION_DELEGATE != null) {
+                // Velocity 3.1.0 added LoginInboundConnection which is used in the login state,
+                // but that class doesn't have a Channel field. However, it does have
+                // InitialInboundConnection as a field
+                connection = getCastedValue(connection, INITIAL_CONNECTION_DELEGATE);
+            }
+            Object mcConnection = getValue(connection, INITIAL_MINECRAFT_CONNECTION);
             Channel channel = getCastedValue(mcConnection, CHANNEL);
 
             player = channel.attr(playerAttribute).get();