From 59ab01a55906cd2b5ff94b8a475add25cff27260 Mon Sep 17 00:00:00 2001
From: coehlrich <coehlrich@users.noreply.github.com>
Date: Wed, 11 Jan 2023 10:45:04 +1300
Subject: [PATCH] Add ClientChatReceivedEvent for system messages (#9284)

---
 .../multiplayer/chat/ChatListener.java.patch  |  9 ++++++
 .../client/ForgeHooksClient.java              | 13 +++++++++
 .../client/event/ClientChatReceivedEvent.java | 29 +++++++++++++++++++
 .../resources/assets/forge/lang/en_us.json    |  2 ++
 4 files changed, 53 insertions(+)

diff --git a/patches/minecraft/net/minecraft/client/multiplayer/chat/ChatListener.java.patch b/patches/minecraft/net/minecraft/client/multiplayer/chat/ChatListener.java.patch
index 159a2402f2..04d8c240fd 100644
--- a/patches/minecraft/net/minecraft/client/multiplayer/chat/ChatListener.java.patch
+++ b/patches/minecraft/net/minecraft/client/multiplayer/chat/ChatListener.java.patch
@@ -30,3 +30,12 @@
                 this.m_241119_(p_251766_, component);
              }
           }
+@@ -159,6 +_,8 @@
+ 
+    public void m_240494_(Component p_240522_, boolean p_240642_) {
+       if (!this.f_240348_.f_91066_.m_231833_().m_231551_() || !this.f_240348_.m_91246_(this.m_240473_(p_240522_))) {
++         p_240522_ = net.minecraftforge.client.ForgeHooksClient.onClientSystemChat(p_240522_, p_240642_);
++         if (p_240522_ == null) return;
+          if (p_240642_) {
+             this.f_240348_.f_91065_.m_93063_(p_240522_, false);
+          } else {
diff --git a/src/main/java/net/minecraftforge/client/ForgeHooksClient.java b/src/main/java/net/minecraftforge/client/ForgeHooksClient.java
index 33d1aa6f95..c57b8b0737 100644
--- a/src/main/java/net/minecraftforge/client/ForgeHooksClient.java
+++ b/src/main/java/net/minecraftforge/client/ForgeHooksClient.java
@@ -72,10 +72,12 @@ import net.minecraft.core.Direction;
 import net.minecraft.locale.Language;
 import net.minecraft.network.Connection;
 import net.minecraft.network.chat.ChatType;
+import net.minecraft.network.chat.ChatTypeDecoration;
 import net.minecraft.network.chat.CommonComponents;
 import net.minecraft.network.chat.Component;
 import net.minecraft.network.chat.FormattedText;
 import net.minecraft.network.chat.PlayerChatMessage;
+import net.minecraft.network.chat.Style;
 import net.minecraft.network.protocol.status.ServerStatus;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.server.packs.resources.Resource;
@@ -974,6 +976,17 @@ public class ForgeHooksClient
         return MinecraftForge.EVENT_BUS.post(event) ? null : event.getMessage();
     }
 
+    private static final ChatTypeDecoration SYSTEM_CHAT_TYPE_DECORATION = new ChatTypeDecoration("forge.chatType.system", List.of(ChatTypeDecoration.Parameter.CONTENT), Style.EMPTY);
+    private static final ChatType SYSTEM_CHAT_TYPE = new ChatType(SYSTEM_CHAT_TYPE_DECORATION, SYSTEM_CHAT_TYPE_DECORATION);
+    private static final ChatType.Bound SYSTEM_CHAT_TYPE_BOUND = SYSTEM_CHAT_TYPE.bind(Component.literal("System"));
+
+    @Nullable
+    public static Component onClientSystemChat(Component message, boolean overlay)
+    {
+        ClientChatReceivedEvent.System event = new ClientChatReceivedEvent.System(SYSTEM_CHAT_TYPE_BOUND, message, overlay);
+        return MinecraftForge.EVENT_BUS.post(event) ? null : event.getMessage();
+    }
+
     @NotNull
     public static String onClientSendMessage(String message)
     {
diff --git a/src/main/java/net/minecraftforge/client/event/ClientChatReceivedEvent.java b/src/main/java/net/minecraftforge/client/event/ClientChatReceivedEvent.java
index 8a2294f8f7..59059bfe4b 100644
--- a/src/main/java/net/minecraftforge/client/event/ClientChatReceivedEvent.java
+++ b/src/main/java/net/minecraftforge/client/event/ClientChatReceivedEvent.java
@@ -118,4 +118,33 @@ public class ClientChatReceivedEvent extends Event
             return this.playerChatMessage;
         }
     }
+
+    /**
+     * Fired when a system chat message is received on the client.
+     *
+     * <p>This event is {@linkplain Cancelable cancellable}, and does not {@linkplain HasResult have a result}.
+     * If the event is cancelled, the message is not displayed in the chat message window or in the overlay.</p>
+     *
+     * <p>This event is fired on the {@linkplain MinecraftForge#EVENT_BUS main Forge event bus},
+     * only on the {@linkplain LogicalSide#CLIENT logical client}.</p>
+     */
+    public static class System extends ClientChatReceivedEvent
+    {
+        private final boolean overlay;
+
+        @ApiStatus.Internal
+        public System(ChatType.Bound boundChatType, Component message, boolean overlay)
+        {
+            super(boundChatType, message, Util.NIL_UUID);
+            this.overlay = overlay;
+        }
+
+        /**
+         * {@return whether the message goes to the overlay}
+         */
+        public boolean isOverlay()
+        {
+            return this.overlay;
+        }
+    }
 }
\ No newline at end of file
diff --git a/src/main/resources/assets/forge/lang/en_us.json b/src/main/resources/assets/forge/lang/en_us.json
index 3fc486fde2..c3f61062d1 100644
--- a/src/main/resources/assets/forge/lang/en_us.json
+++ b/src/main/resources/assets/forge/lang/en_us.json
@@ -220,5 +220,7 @@
   "forge.experimentalsettings.tooltip": "This world uses experimental settings, which could stop working at any time.",
   "forge.selectWorld.backupWarning.experimental.additional" : "This message will not show again for this world.",
 
+  "forge.chatType.system": "{0}",
+
   "pack.forge.description": "Forge resource pack"
 }