From 1ce9b7c454c15a42313d2bba58caf185520a8bf5 Mon Sep 17 00:00:00 2001
From: Kodi Craft <kodi@kdcf.me>
Date: Mon, 8 Jul 2024 14:57:37 +0200
Subject: [PATCH] Move shared boilerplate in servers to Amethyst.Server

---
 lib/servers/generic.ex | 27 +++++++++++++++++++++++++++
 lib/servers/stage1.ex  | 16 +++++++---------
 lib/servers/status.ex  | 18 ++----------------
 3 files changed, 36 insertions(+), 25 deletions(-)

diff --git a/lib/servers/generic.ex b/lib/servers/generic.ex
index bad4dd9..5731a0a 100644
--- a/lib/servers/generic.ex
+++ b/lib/servers/generic.ex
@@ -37,3 +37,30 @@ defmodule Amethyst.Server.Generic do
     end
   end
 end
+
+defmodule Amethyst.Server do
+  @moduledoc """
+  This module includes shared boilerplate code for all stages of the server.
+  """
+
+  defmacro __using__(_opts) do
+    quote do
+      @spec serve(:gen_tcp.socket()) :: no_return()
+      def serve(client) do
+        {id, data} = Amethyst.Server.Generic.get_packet(client)
+        packet = deserialize(id, data)
+        Logger.debug("Got packet #{inspect(packet)}")
+        handle(packet, client)
+        serve(client)
+      end
+
+
+      def transmit(packet, client) do
+        Logger.debug("Transmitting #{inspect(packet)}")
+        data = serialize(packet)
+        length = byte_size(data) |> Amethyst.Minecraft.Write.varint()
+        :gen_tcp.send(client, length <> data)
+      end
+    end
+  end
+end
diff --git a/lib/servers/stage1.ex b/lib/servers/stage1.ex
index 50c60d4..9e60f0f 100644
--- a/lib/servers/stage1.ex
+++ b/lib/servers/stage1.ex
@@ -19,16 +19,9 @@ defmodule Amethyst.Server.Stage1 do
   This module contains the stage 1 (Handshaking) server logic.
   """
   require Logger
-  alias Amethyst.Minecraft.Read
+  use Amethyst.Server
 
-  @spec serve(:gen_tcp.socket()) :: no_return()
-  def serve(client) do
-    {id, data} = Amethyst.Server.Generic.get_packet(client)
-    packet = deserialize(id, data)
-    Logger.debug("Got packet #{inspect(packet)}")
-    handle(packet, client)
-    serve(client)
-  end
+  alias Amethyst.Minecraft.Read
 
   ## DESERIALIZATION
   # Handshake https://wiki.vg/Protocol#Handshake
@@ -48,6 +41,11 @@ defmodule Amethyst.Server.Stage1 do
     raise RuntimeError, "Got unknown packet type #{type}!"
   end
 
+  ## SERIALIZATION
+  def serialize(_) do
+    raise RuntimeError, "No packets can be transmitted while still in the handshake stage!"
+  end
+
   ## HANDLING
   # Handshake https://wiki.vg/Protocol#Handshake
   @spec handle(any(), any()) :: no_return()
diff --git a/lib/servers/status.ex b/lib/servers/status.ex
index e0e8bb9..5fc2d29 100644
--- a/lib/servers/status.ex
+++ b/lib/servers/status.ex
@@ -20,25 +20,11 @@ defmodule Amethyst.Server.Status do
   is only asking a bit of information.
   """
   require Logger
+  use Amethyst.Server
+
   alias Amethyst.Minecraft.Read
   alias Amethyst.Minecraft.Write
 
-  @spec serve(:gen_tcp.socket()) :: no_return()
-  def serve(client) do
-    {id, data} = Amethyst.Server.Generic.get_packet(client)
-    packet = deserialize(id, data)
-    Logger.debug("Got packet #{inspect(packet)}")
-    handle(packet, client)
-    serve(client)
-  end
-
-  def transmit(packet, client) do
-    Logger.debug("Transmitting #{inspect(packet)}")
-    data = serialize(packet)
-    length = byte_size(data) |> Write.varint()
-    :gen_tcp.send(client, length <> data)
-  end
-
   ## DESERIALIZATION
   # Status Request https://wiki.vg/Protocol#Status_Request
   def deserialize(0x00, _) do