Implement chat newline rewriter

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/data/ChatNewlineRewriter.java

@@ -0,0 +1,149 @@
+/*
+ * This file is part of ViaRewind - https://github.com/ViaVersion/ViaRewind
+ * Copyright (C) 2018-2026 ViaVersion and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.viaversion.viarewind.protocol.v1_8to1_7_6_10.data;
+
+import com.viaversion.viaversion.libs.gson.JsonArray;
+import com.viaversion.viaversion.libs.gson.JsonElement;
+import com.viaversion.viaversion.libs.gson.JsonObject;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+public class ChatNewlineRewriter {
+    public static List<JsonObject> splitChatComponentByNewline(JsonElement element) {
+        return splitChatComponentByNewline(element, new JsonObject());
+    }
+
+    private static List<JsonObject> splitChatComponentByNewline(JsonElement element, JsonObject inheritedStyle) {
+        List<JsonObject> results = new ArrayList<>();
+        if (element == null || element.isJsonNull()) {
+            return results;
+        }
+
+        if (element.isJsonPrimitive()) {
+            String text = element.getAsString();
+            for (String part : text.split("\n", -1)) {
+                JsonObject obj = inheritedStyle.deepCopy();
+                obj.addProperty("text", part);
+                results.add(obj);
+            }
+            return results;
+        }
+
+        if (element.isJsonArray()) {
+            for (JsonElement child : element.getAsJsonArray()) {
+                results.addAll(splitChatComponentByNewline(child, inheritedStyle));
+            }
+            return results;
+        }
+
+        if (!element.isJsonObject()) {
+            return results;
+        }
+
+        JsonObject obj = element.getAsJsonObject();
+
+        // Build the style for this node: inherit first, then override with this object's style
+        JsonObject currentStyle = inheritedStyle.deepCopy();
+        for (Map.Entry<String, JsonElement> entry : obj.entrySet()) {
+            String key = entry.getKey();
+            if (!"text".equals(key) && !"extra".equals(key)) {
+                currentStyle.add(key, entry.getValue());
+            }
+        }
+
+        // Gather components in order: base text then extra array
+        List<JsonElement> ordered = new ArrayList<>();
+        if (obj.has("text")) {
+            ordered.add(obj.get("text"));
+        }
+        if (obj.has("extra") && obj.get("extra").isJsonArray()) {
+            for (JsonElement extra : obj.getAsJsonArray("extra")) {
+                ordered.add(extra);
+            }
+        }
+
+        // If there is no text/extra, return a single object with the style
+        if (ordered.isEmpty()) {
+            results.add(currentStyle);
+            return results;
+        }
+
+        // Build lines by concatenating split pieces
+        List<JsonObject> currentLine = new ArrayList<>();
+        for (JsonElement part : ordered) {
+            if (part == null || part.isJsonNull()) {
+                continue;
+            }
+
+            if (part.isJsonPrimitive()) {
+                String text = part.getAsString();
+                String[] split = text.split("\n", -1);
+                for (int i = 0; i < split.length; i++) {
+                    JsonObject piece = currentStyle.deepCopy();
+                    piece.addProperty("text", split[i]);
+                    currentLine.add(piece);
+
+                    if (i < split.length - 1) {
+                        results.add(mergeLine(currentLine));
+                        currentLine.clear();
+                    }
+                }
+                continue;
+            }
+
+            if (part.isJsonObject() || part.isJsonArray()) {
+                List<JsonObject> splitParts = splitChatComponentByNewline(part, currentStyle);
+                for (int i = 0; i < splitParts.size(); i++) {
+                    currentLine.add(splitParts.get(i));
+                    if (i < splitParts.size() - 1) {
+                        results.add(mergeLine(currentLine));
+                        currentLine.clear();
+                    }
+                }
+            }
+        }
+
+        if (!currentLine.isEmpty()) {
+            results.add(mergeLine(currentLine));
+        }
+
+        return results;
+    }
+
+    private static JsonObject mergeLine(List<JsonObject> lineParts) {
+        if (lineParts.isEmpty()) {
+            JsonObject empty = new JsonObject();
+            empty.addProperty("text", "");
+            return empty;
+        }
+
+        JsonObject first = lineParts.get(0);
+        if (lineParts.size() == 1) {
+            return first;
+        }
+
+        JsonArray extra = new JsonArray();
+        for (int i = 1; i < lineParts.size(); i++) {
+            extra.add(lineParts.get(i));
+        }
+        first.add("extra", extra);
+        return first;
+    }
+}

common/src/main/java/com/viaversion/viarewind/protocol/v1_8to1_7_6_10/rewriter/PlayerPacketRewriter1_8.java

@@ -30,6 +30,7 @@
 import com.viaversion.viarewind.protocol.v1_7_6_10to1_7_2_5.packet.ServerboundPackets1_7_2_5;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.Protocol1_8To1_7_6_10;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.data.ChatItemRewriter;
+import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.data.ChatNewlineRewriter;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.provider.TitleRenderProvider;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.storage.EntityTracker1_8;
 import com.viaversion.viarewind.protocol.v1_8to1_7_6_10.storage.GameProfileStorage;
@@ -46,6 +47,7 @@
 import com.viaversion.viaversion.api.rewriter.RewriterBase;
 import com.viaversion.viaversion.api.type.Types;
 import com.viaversion.viaversion.libs.gson.JsonElement;
+import com.viaversion.viaversion.libs.gson.JsonObject;
 import com.viaversion.viaversion.protocols.v1_8to1_9.packet.ClientboundPackets1_8;
 import com.viaversion.viaversion.protocols.v1_8to1_9.packet.ServerboundPackets1_8;
 import com.viaversion.viaversion.util.ComponentUtil;
@@ -70,13 +72,27 @@ protected void registerPackets() {
             @Override
             public void register() {
                 map(Types.COMPONENT); // Chat message
+
                 handler(wrapper -> {
                     final JsonElement json = wrapper.get(Types.COMPONENT, 0);
-                    ChatItemRewriter.toClient(protocol, wrapper.user(), json);
-
                     final int position = wrapper.read(Types.BYTE);
+
                     if (position == 2) { // Above hotbar
                         wrapper.cancel();
+                        return;
+                    }
+
+                    ChatItemRewriter.toClient(protocol, wrapper.user(), json);
+                    List<JsonObject> splitComponents = ChatNewlineRewriter.splitChatComponentByNewline(json);
+
+                    if (splitComponents.size() > 1) {
+                        wrapper.cancel();
+
+                        for (JsonObject split : splitComponents) {
+                            PacketWrapper newWrapper = wrapper.create(ClientboundPackets1_7_2_5.CHAT);
+                            newWrapper.write(Types.COMPONENT, split);
+                            newWrapper.send(Protocol1_8To1_7_6_10.class);
+                        }
                     }
                 });
             }