1 files changed, 66 insertions, 2 deletions
diff --git a/azalea-protocol/src/packets/game/s_container_click.rs b/azalea-protocol/src/packets/game/s_container_click.rs
index ed68de6e..b7b70888 100755
--- a/azalea-protocol/src/packets/game/s_container_click.rs
+++ b/azalea-protocol/src/packets/game/s_container_click.rs
@@ -1,6 +1,6 @@
 use std::collections::HashMap;
 
-use azalea_buf::AzBuf;
+use azalea_buf::{AzBuf, AzaleaWrite};
 use azalea_inventory::{ItemStack, operations::ClickType};
 use azalea_protocol_macros::ServerboundGamePacket;
 
@@ -13,6 +13,70 @@ pub struct ServerboundContainerClick {
     pub slot_num: i16,
     pub button_num: u8,
     pub click_type: ClickType,
-    pub changed_slots: HashMap<u16, ItemStack>,
+    pub changed_slots: HashMap<u16, HashedStack>,
     pub carried_item: ItemStack,
 }
+
+/// Similar to an [`ItemStack`] but only carrying a CRC32 hash of the value of
+/// added data components instead of their entire contents.
+#[derive(Clone, Debug, AzBuf)]
+pub struct HashedStack(pub Option<HashedActualItem>);
+
+#[derive(Clone, Debug, AzBuf)]
+pub struct HashedActualItem {
+    pub kind: azalea_registry::Item,
+    #[var]
+    pub count: i32,
+    pub components: HashedPatchMap,
+}
+
+#[derive(Clone, Debug, AzBuf)]
+pub struct HashedPatchMap {
+    /// The value is a CRC32 hash of the data component's network serialization.
+    /// (kind + data)
+    #[limit(256)]
+    pub added_components: Vec<(azalea_registry::DataComponentKind, u32)>,
+    #[limit(256)]
+    pub removed_components: Vec<azalea_registry::DataComponentKind>,
+}
+
+/// Convert your [`ItemStack`] into a [`HashedStack`] by hashing the data
+/// components.
+///
+/// This will be necessary if you're writing a client or server, but if you're
+/// just making a proxy then you can remove the `crc32` dependency by disabling
+/// the `crc32` feature on `azalea-protocol`.
+#[cfg(feature = "crc32")]
+impl From<&ItemStack> for HashedStack {
+    fn from(item: &ItemStack) -> Self {
+        let ItemStack::Present(item) = item else {
+            return Self(None);
+        };
+
+        let mut added_components = Vec::new();
+        let mut removed_components = Vec::new();
+
+        for (&kind, data) in &item.components.components {
+            if let Some(data) = data {
+                // encodeCap in TypedDataComponent.java
+                let mut buf = Vec::new();
+                kind.azalea_write(&mut buf).unwrap();
+                data.encode(&mut buf).unwrap();
+                added_components.push((kind, crc32fast::hash(&buf)));
+            } else {
+                removed_components.push(kind);
+            }
+        }
+
+        let components = HashedPatchMap {
+            added_components,
+            removed_components,
+        };
+        let item = HashedActualItem {
+            kind: item.kind,
+            count: item.count,
+            components,
+        };
+        Self(Some(item))
+    }
+}