From 2b2384acc16a07fb2b0e94aeebef48eaa62f7f43 Mon Sep 17 00:00:00 2001
From: Nassim Jahnke <nassim@njahnke.dev>
Date: Fri, 15 Sep 2023 18:13:12 +1000
Subject: [PATCH] Remove new trim patterns in 1.20->1.19 Fixes #570

---
 .../packets/BlockItemPackets1_20.java         | 49 +++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_19_4to1_20/packets/BlockItemPackets1_20.java b/common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_19_4to1_20/packets/BlockItemPackets1_20.java
index e4dad7f6..90767c05 100644
--- a/common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_19_4to1_20/packets/BlockItemPackets1_20.java
+++ b/common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_19_4to1_20/packets/BlockItemPackets1_20.java
@@ -23,19 +23,28 @@ import com.viaversion.viabackwards.protocol.protocol1_19_4to1_20.storage.BackSig
 import com.viaversion.viaversion.api.minecraft.BlockChangeRecord;
 import com.viaversion.viaversion.api.minecraft.Position;
 import com.viaversion.viaversion.api.minecraft.blockentity.BlockEntity;
+import com.viaversion.viaversion.api.minecraft.item.Item;
 import com.viaversion.viaversion.api.protocol.remapper.PacketHandlers;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.libs.opennbt.tag.builtin.CompoundTag;
 import com.viaversion.viaversion.libs.opennbt.tag.builtin.ListTag;
+import com.viaversion.viaversion.libs.opennbt.tag.builtin.StringTag;
 import com.viaversion.viaversion.libs.opennbt.tag.builtin.Tag;
 import com.viaversion.viaversion.protocols.protocol1_18to1_17_1.types.Chunk1_18Type;
 import com.viaversion.viaversion.protocols.protocol1_19_4to1_19_3.ClientboundPackets1_19_4;
 import com.viaversion.viaversion.protocols.protocol1_19_4to1_19_3.ServerboundPackets1_19_4;
 import com.viaversion.viaversion.protocols.protocol1_19_4to1_19_3.rewriter.RecipeRewriter1_19_4;
 import com.viaversion.viaversion.rewriter.BlockRewriter;
+import com.viaversion.viaversion.util.Key;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 public final class BlockItemPackets1_20 extends ItemRewriter<ClientboundPackets1_19_4, ServerboundPackets1_19_4, Protocol1_19_4To1_20> {
 
+    private static final Set<String> NEW_TRIM_PATTERNS = new HashSet<>(Arrays.asList("host", "raiser", "shaper", "silence", "wayfinder"));
+
     public BlockItemPackets1_20(final Protocol1_19_4To1_20 protocol) {
         super(protocol);
     }
@@ -140,6 +149,46 @@ public final class BlockItemPackets1_20 extends ItemRewriter<ClientboundPackets1
         new RecipeRewriter1_19_4<>(protocol).register(ClientboundPackets1_19_4.DECLARE_RECIPES);
     }
 
+    @Override
+    public @Nullable Item handleItemToClient(@Nullable final Item item) {
+        if (item == null) {
+            return null;
+        }
+
+        super.handleItemToClient(item);
+
+        // Remove new trim tags
+        final Tag trimTag;
+        if (item.tag() != null && (trimTag = item.tag().get("Trim")) instanceof CompoundTag) {
+            final Tag patternTag = ((CompoundTag) trimTag).get("pattern");
+            if (patternTag instanceof StringTag) {
+                final StringTag patternStringTag = (StringTag) patternTag;
+                final String pattern = Key.stripMinecraftNamespace(patternStringTag.getValue());
+                if (NEW_TRIM_PATTERNS.contains(pattern)) {
+                    item.tag().remove("Trim");
+                    item.tag().put(nbtTagName + "|Trim", trimTag);
+                }
+            }
+        }
+        return item;
+    }
+
+    @Override
+    public @Nullable Item handleItemToServer(@Nullable final Item item) {
+        if (item == null) {
+            return null;
+        }
+
+        super.handleItemToServer(item);
+
+        // Add back original trim tag
+        final Tag trimTag;
+        if (item.tag() != null && (trimTag = item.tag().remove(nbtTagName + "|Trim")) != null) {
+            item.tag().put("Trim", trimTag);
+        }
+        return item;
+    }
+
     private void handleBlockEntity(final BlockEntity blockEntity) {
         // Check for signs
         if (blockEntity.typeId() != 7 && blockEntity.typeId() != 8) {