From 17c7360c76c580befd679043075346733c7e717b Mon Sep 17 00:00:00 2001
From: Kyler <kylerolsen17@gmail.com>
Date: Sun, 14 Sep 2025 21:46:57 -0600
Subject: [PATCH] Replaced `PacketArray` trait with `McType` macro

---
 purple_cello_mc_derive/src/lib.rs | 48 +++++++++++++++++++++++++++++++
 src/mc_types.rs                   | 43 ++++++++++++++++++++++++---
 src/mc_types/helpers.rs           | 13 ---------
 src/mc_types/packet.rs            | 23 ---------------
 4 files changed, 87 insertions(+), 40 deletions(-)

diff --git a/purple_cello_mc_derive/src/lib.rs b/purple_cello_mc_derive/src/lib.rs
index b89f595..3867a04 100644
--- a/purple_cello_mc_derive/src/lib.rs
+++ b/purple_cello_mc_derive/src/lib.rs
@@ -107,3 +107,51 @@ pub fn derive_packet(input: TokenStream) -> TokenStream {
 
     expanded.into()
 }
+
+#[proc_macro_derive(McType)]
+pub fn derive_mctype_struct(input: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    let name = &input.ident;
+
+    let Data::Struct(data_struct) = input.data else {
+        return syn::Error::new_spanned(name, "McType can only be derived for structs")
+            .to_compile_error()
+            .into();
+    };
+
+    let Fields::Named(fields) = data_struct.fields else {
+        return syn::Error::new_spanned(name, "McType requires named fields")
+            .to_compile_error()
+            .into();
+    };
+
+    // build field accessors
+    let read_fields = fields.named.iter().map(|f| {
+        let fname = &f.ident;
+        let fty = &f.ty;
+        quote! { #fname: <#fty as McType>::get(data)? }
+    });
+
+    let write_fields = fields.named.iter().map(|f| {
+        let fname = &f.ident;
+        quote! { out.extend(self.#fname.convert()); }
+    });
+
+    let expanded = quote! {
+        impl McType for #name {
+            fn get(data: &mut Vec<u8>) -> Result<Self> {
+                Ok(Self {
+                    #(#read_fields),*
+                })
+            }
+
+            fn convert(&self) -> Vec<u8> {
+                let mut out = Vec::new();
+                #(#write_fields)*
+                out
+            }
+        }
+    };
+
+    expanded.into()
+}
diff --git a/src/mc_types.rs b/src/mc_types.rs
index 3cd4be9..5778e37 100644
--- a/src/mc_types.rs
+++ b/src/mc_types.rs
@@ -10,7 +10,7 @@ use serde::{Serialize, Deserialize};
 
 pub use crate::mc_types::error::PacketError;
 pub use crate::mc_types::protocol::{ProtocolRead, ProtocolConnection};
-pub use crate::mc_types::packet::{Result, Packet, PacketArray};
+pub use crate::mc_types::packet::{Result, Packet};
 use crate::mc_types::helpers::*;
 
 pub const VERSION_NAME: &str = "1.21";
@@ -120,7 +120,42 @@ impl McType for String {
     fn convert(&self) -> Vec<u8> { convert_string(*self) }
 }
 
-impl McType for Vec<u8> {
-    fn get(data: &mut Vec<u8>) -> Result<Self> { Ok(get_byte_array(data)) }
-    fn convert(&self) -> Vec<u8> { convert_byte_array(*self) }
+impl<T: McType> McType for Vec<T> {
+    fn get(data: &mut Vec<u8>) -> Result<Self> {
+        let length = get_var_int(data)?;
+        let mut out = Vec::with_capacity(length as usize);
+        for _ in 0..length {
+            out.push(T::get(data)?);
+        }
+        Ok(out)
+    }
+
+    fn convert(&self) -> Vec<u8> {
+        let mut data = convert_var_int(self.len() as i32);
+        for el in self {
+            data.extend(el.convert());
+        }
+        data
+    }
+}
+
+impl<T: McType> McType for Option<T> {
+    fn get(data: &mut Vec<u8>) -> Result<Self> {
+        if get_bool(data) {
+            Ok(Some(T::get(data)?))
+        } else {
+            Ok(None)
+        }
+    }
+
+    fn convert(&self) -> Vec<u8> {
+        match self {
+            Some(v) => {
+                let mut data = convert_bool(true);
+                data.extend(v.convert());
+                data
+            }
+            None => convert_bool(false),
+        }
+    }
 }
diff --git a/src/mc_types/helpers.rs b/src/mc_types/helpers.rs
index d73e481..30202f4 100644
--- a/src/mc_types/helpers.rs
+++ b/src/mc_types/helpers.rs
@@ -242,16 +242,3 @@ pub fn convert_string(s: &str) -> Vec<u8> {
     data.append(&mut s.as_bytes().to_vec());
     data
 }
-
-pub fn get_byte_array(data: &mut Vec<u8>) -> Result<Vec<u8>> {
-    let length = get_var_int(data)? as usize;
-    let buffer = data[..length].to_vec();
-    for _ in 0..length { data.remove(0); }
-    Ok(buffer)
-}
-pub fn convert_byte_array(mut s: &mut Vec<u8>) -> Vec<u8> {
-    let length = s.len() as i32;
-    let mut data = convert_var_int(length);
-    data.append(&mut s);
-    data
-}
diff --git a/src/mc_types/packet.rs b/src/mc_types/packet.rs
index 70843be..74b825f 100644
--- a/src/mc_types/packet.rs
+++ b/src/mc_types/packet.rs
@@ -30,26 +30,3 @@ pub trait Packet: Sized {
         conn.write_data(&mut self.convert()).await
     }
 }
-
-pub trait PacketArray: Sized {
-    fn get(data: &mut Vec<u8>) -> Result<Self>;
-    fn convert(&self) -> Vec<u8>;
-
-    fn get_array(data: &mut Vec<u8>) -> Result<Vec<Self>> {
-        let length = get_var_int(data)?;
-        let mut out_data: Vec<Self> = vec![];
-        for _ in 0..length {
-            out_data.push(Self::get(data)?);
-        }
-        Ok(out_data)
-    }
-
-    fn convert_array(array: &mut Vec<Self>) -> Vec<u8> {
-        let length = array.len() as i32;
-        let mut data: Vec<u8> = convert_var_int(length);
-        for element in array {
-            data.append(&mut Self::convert(element));
-        }
-        data
-    }
-}