Added a SkinApplyEvent that can cancel/edit the to be applied skin

api/src/main/java/org/geysermc/floodgate/api/FloodgateApi.java

@@ -30,6 +30,7 @@ import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
 import org.geysermc.cumulus.form.Form;
 import org.geysermc.cumulus.form.util.FormBuilder;
+import org.geysermc.floodgate.api.event.FloodgateEventBus;
 import org.geysermc.floodgate.api.link.PlayerLink;
 import org.geysermc.floodgate.api.player.FloodgatePlayer;
 import org.geysermc.floodgate.api.unsafe.Unsafe;
@@ -148,6 +149,10 @@ public interface FloodgateApi {
      */
     CompletableFuture<String> getGamertagFor(long xuid);
 
+    default FloodgateEventBus getEventBus() {
+        return InstanceHolder.getEventBus();
+    }
+
     /**
      * Returns the instance that manages all the linking.
      */

api/src/main/java/org/geysermc/floodgate/api/InstanceHolder.java

@@ -27,6 +27,7 @@ package org.geysermc.floodgate.api;
 
 import java.util.UUID;
 import lombok.Getter;
+import org.geysermc.floodgate.api.event.FloodgateEventBus;
 import org.geysermc.floodgate.api.handshake.HandshakeHandlers;
 import org.geysermc.floodgate.api.inject.PlatformInjector;
 import org.geysermc.floodgate.api.link.PlayerLink;
@@ -35,6 +36,7 @@ import org.geysermc.floodgate.api.packet.PacketHandlers;
 public final class InstanceHolder {
     @Getter private static FloodgateApi api;
     @Getter private static PlayerLink playerLink;
+    @Getter private static FloodgateEventBus eventBus;
 
     @Getter private static PlatformInjector injector;
     @Getter private static PacketHandlers packetHandlers;
@@ -44,11 +46,12 @@ public final class InstanceHolder {
     public static boolean set(
             FloodgateApi floodgateApi,
             PlayerLink link,
+            FloodgateEventBus floodgateEventBus,
             PlatformInjector platformInjector,
             PacketHandlers packetHandlers,
             HandshakeHandlers handshakeHandlers,
-            UUID key) {
-
+            UUID key
+    ) {
         if (storedKey != null) {
             if (!storedKey.equals(key)) {
                 return false;
@@ -59,14 +62,10 @@ public final class InstanceHolder {
 
         api = floodgateApi;
         playerLink = link;
+        eventBus = floodgateEventBus;
         injector = platformInjector;
         InstanceHolder.packetHandlers = packetHandlers;
         InstanceHolder.handshakeHandlers = handshakeHandlers;
         return true;
     }
-
-    @SuppressWarnings("unchecked")
-    public static <T extends FloodgateApi> T castApi(Class<T> cast) {
-        return (T) api;
-    }
 }

api/src/main/java/org/geysermc/floodgate/api/event/FloodgateEventBus.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2019-2022 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Floodgate
+ */
+
+package org.geysermc.floodgate.api.event;
+
+import org.geysermc.event.bus.EventBus;
+
+public interface FloodgateEventBus extends EventBus<Object, FloodgateSubscriber<?>> {
+}

api/src/main/java/org/geysermc/floodgate/api/event/FloodgateSubscriber.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2019-2022 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Floodgate
+ */
+
+package org.geysermc.floodgate.api.event;
+
+import org.geysermc.event.subscribe.Subscriber;
+
+public interface FloodgateSubscriber<T> extends Subscriber<T> {
+}

api/src/main/java/org/geysermc/floodgate/api/event/skin/SkinApplyEvent.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2019-2022 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Floodgate
+ */
+
+package org.geysermc.floodgate.api.event.skin;
+
+import org.checkerframework.checker.nullness.qual.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.checkerframework.common.returnsreceiver.qual.This;
+import org.geysermc.event.Cancellable;
+import org.geysermc.floodgate.api.player.FloodgatePlayer;
+
+/**
+ * An event that's fired when Floodgate receives a player skin. The event will be cancelled by
+ * default when hasSkin is true, as Floodgate by default only applies skins when the player has no
+ * skin applied yet.
+ */
+public interface SkinApplyEvent extends Cancellable {
+    /**
+     * Returns the player that will receive the skin.
+     */
+    @NonNull FloodgatePlayer player();
+
+    /**
+     * Returns the skin texture currently applied to the player.
+     */
+    @Nullable SkinData currentSkin();
+
+    /**
+     * Returns the skin texture to be applied to the player.
+     */
+    @NonNull SkinData newSkin();
+
+    /**
+     * Sets the skin texture to be applied to the player
+     *
+     * @param skinData the skin to apply
+     * @return this
+     */
+    @This SkinApplyEvent newSkin(@NonNull SkinData skinData);
+
+    interface SkinData {
+        /**
+         * Returns the value of the skin texture.
+         */
+        @NonNull String value();
+
+        /**
+         * Returns the signature of the skin texture.
+         */
+        @NonNull String signature();
+    }
+}