From 025603027e92f48ba03a07ffec5164ce38e1d805 Mon Sep 17 00:00:00 2001
From: Nassim Jahnke <nassim@njahnke.dev>
Date: Tue, 30 Apr 2024 22:28:46 +0200
Subject: [PATCH] Remove default components from trade list

---
 .../BlockItemPacketRewriter1_20_5.java        | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_20_3to1_20_5/rewriter/BlockItemPacketRewriter1_20_5.java b/common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_20_3to1_20_5/rewriter/BlockItemPacketRewriter1_20_5.java
index b7d65b59..73f86835 100644
--- a/common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_20_3to1_20_5/rewriter/BlockItemPacketRewriter1_20_5.java
+++ b/common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_20_3to1_20_5/rewriter/BlockItemPacketRewriter1_20_5.java
@@ -27,6 +27,8 @@ import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.types.chunk.ChunkType1_20_2;
 import com.viaversion.viaversion.api.type.types.version.Types1_20_3;
 import com.viaversion.viaversion.api.type.types.version.Types1_20_5;
+import com.viaversion.viaversion.libs.opennbt.tag.builtin.CompoundTag;
+import com.viaversion.viaversion.libs.opennbt.tag.builtin.ListTag;
 import com.viaversion.viaversion.protocols.protocol1_20_3to1_20_2.packet.ServerboundPacket1_20_3;
 import com.viaversion.viaversion.protocols.protocol1_20_3to1_20_2.packet.ServerboundPackets1_20_3;
 import com.viaversion.viaversion.protocols.protocol1_20_3to1_20_2.rewriter.RecipeRewriter1_20_3;
@@ -141,10 +143,14 @@ public final class BlockItemPacketRewriter1_20_5 extends BackwardsStructuredItem
             final int size = wrapper.passthrough(Type.VAR_INT);
             for (int i = 0; i < size; i++) {
                 final Item input = handleItemToClient(wrapper.user(), wrapper.read(Types1_20_5.ITEM_COST));
+                cleanInput(input);
                 wrapper.write(Type.ITEM1_20_2, input);
+
                 final Item result = handleItemToClient(wrapper.user(), wrapper.read(Types1_20_5.ITEM));
                 wrapper.write(Type.ITEM1_20_2, result);
+
                 final Item secondInput = handleItemToClient(wrapper.user(), wrapper.read(Types1_20_5.OPTIONAL_ITEM_COST));
+                cleanInput(secondInput);
                 wrapper.write(Type.ITEM1_20_2, secondInput);
 
                 wrapper.passthrough(Type.BOOLEAN); // Out of stock
@@ -172,6 +178,42 @@ public final class BlockItemPacketRewriter1_20_5 extends BackwardsStructuredItem
         });
     }
 
+    private void cleanInput(@Nullable final Item item) {
+        // Try to maybe hopefully get the tag matching to what the client will try to input by removing default data
+        if (item == null || item.tag() == null) {
+            return;
+        }
+
+        final CompoundTag tag = item.tag();
+        tag.remove("VV|DataComponents");
+
+        final CompoundTag display = tag.getCompoundTag("display");
+        if (display != null) {
+            removeEmptyList(display, "Lore");
+            if (display.isEmpty()) {
+                tag.remove("display");
+            }
+        }
+
+        removeEmptyList(tag, "Enchantments");
+        removeEmptyList(tag, "AttributeModifiers");
+
+        if (tag.getInt("RepairCost", -1) == 0) {
+            tag.remove("RepairCost");
+        }
+
+        if (tag.isEmpty()) {
+            item.setTag(null);
+        }
+    }
+
+    private void removeEmptyList(final CompoundTag tag, final String key) {
+        final ListTag<?> list = tag.getListTag(key);
+        if (list != null && list.isEmpty()) {
+            tag.remove(key);
+        }
+    }
+
     @Override
     public @Nullable Item handleItemToClient(final UserConnection connection, @Nullable final Item item) {
         if (item == null) return null;