Backup original book pages for creative mode clients in 1.8->1.9 (ViaVersion#3952)

Author: FlorianMichael

common/src/main/java/com/viaversion/viaversion/protocols/v1_20_3to1_20_5/rewriter/BlockItemPacketRewriter1_20_5.java

@@ -1089,13 +1089,13 @@ private void updateEffects(final ListTag<CompoundTag> effects, final StructuredD
         data.set(StructuredDataKey.SUSPICIOUS_STEW_EFFECTS, suspiciousStewEffects);
     }
 
-    private void updateLodestoneTracker(final boolean tracked, final CompoundTag lodestonePosTag, final String lodestoneDimensionTag, final StructuredDataContainer data) {
+    private void updateLodestoneTracker(final boolean tracked, final CompoundTag lodestonePosTag, final String lodestoneDimension, final StructuredDataContainer data) {
         GlobalBlockPosition position = null;
-        if (lodestonePosTag != null && lodestoneDimensionTag != null) {
+        if (lodestonePosTag != null && lodestoneDimension != null) {
             final int x = lodestonePosTag.getInt("X");
             final int y = lodestonePosTag.getInt("Y");
             final int z = lodestonePosTag.getInt("Z");
-            position = new GlobalBlockPosition(lodestoneDimensionTag, x, y, z);
+            position = new GlobalBlockPosition(lodestoneDimension, x, y, z);
         }
         data.set(StructuredDataKey.LODESTONE_TRACKER, new LodestoneTracker(position, tracked));
     }

common/src/main/java/com/viaversion/viaversion/protocols/v1_8to1_9/rewriter/ItemPacketRewriter1_9.java

@@ -418,6 +418,8 @@ public void register() {
             }
 
             ListTag<StringTag> pages = tag.getListTag("pages", StringTag.class);
+            tag.put(nbtTagName("pages"), pages == null ? new ListTag<>(StringTag.class) : pages.copy());
+
             if (pages == null) {
                 pages = new ListTag<>(Collections.singletonList(new StringTag(ComponentUtil.emptyJsonComponent().toString())));
                 tag.put("pages", pages);
@@ -481,6 +483,32 @@ public void register() {
             item.setTag(tag);
             item.setData((short) data);
         }
+        if (item.identifier() == 387) { // WRITTEN_BOOK
+            CompoundTag tag = item.tag();
+            if (tag != null) {
+                // Prefer saved pages since they are more likely to be accurate
+                ListTag<StringTag> backup = tag.removeUnchecked(nbtTagName("pages"));
+                if (backup != null) {
+                    if (!backup.isEmpty()) {
+                        tag.put("pages", backup);
+                    } else {
+                        tag.remove("pages");
+                        if (tag.isEmpty()) {
+                            item.setTag(null);
+                        }
+                    }
+                } else {
+                    // Fallback to normal pages tag
+                    ListTag<StringTag> pages = tag.getListTag("pages", StringTag.class);
+                    if (pages != null) {
+                        for (int i = 0; i < pages.size(); i++) {
+                            final StringTag page = pages.get(i);
+                            page.setValue(ComponentUtil.convertJsonOrEmpty(page.getValue(), SerializerVersion.V1_9, SerializerVersion.V1_8).toString());
+                        }
+                    }
+                }
+            }
+        }
 
         boolean newItem = item.identifier() >= 198 && item.identifier() <= 212;
         newItem |= item.identifier() == 397 && item.data() == 5;