Structure tweaks

lib/servers/configuration.ex

@@ -24,7 +24,13 @@ defmodule Amethyst.Server.Configuration do
   alias Amethyst.Minecraft.Read
   alias Amethyst.Minecraft.Write
 
+  @impl true
+  def init(state) do
+    state
+  end
+
   ## DESERIALIZATION
+  @impl true
   # Client Information https://wiki.vg/Protocol#Client_Information
   def deserialize(0x00, data) do
     {[locale, view_dist, chat_mode, chat_colors, displayed_skin_parts, main_hand, text_filtering, allow_listing], ""} =
@@ -102,6 +108,7 @@ defmodule Amethyst.Server.Configuration do
   end
 
   ## SERIALIZATION
+  @impl true
   # Cookie Request https://wiki.vg/Protocol#Cookie_Request_(configuration)
   def serialize({:cookie_request, id}) do
     Write.varint(0x00) <> Write.string(id)
@@ -227,6 +234,8 @@ defmodule Amethyst.Server.Configuration do
   end
 
   ## HANDLING
+  @impl true
+  # Serverbound Plugin Message https://wiki.vg/Protocol#Serverbound_Plugin_Message_(configuration)
   def handle({:serverbound_plugin_message, channel, data}, client, state) do
     handle_plugin_message(channel, data, client, state)
   end

lib/servers/generic.ex

@@ -46,12 +46,24 @@ defmodule Amethyst.Server do
   @moduledoc """
   This module includes shared boilerplate code for all stages of the server.
   """
-require Logger
+  require Logger
+
+  @callback init(any()) :: any()
+  @callback deserialize(integer(), binary()) :: any()
+  @callback serialize(any()) :: binary()
+  @callback handle(any(), :gen_tcp.socket(), any()) :: {:ok, any()} | {:unhandled, any()}
 
   defmacro __using__(_opts) do
     quote do
-      @spec serve(:gen_tcp.socket()) :: no_return()
+      @behaviour Amethyst.Server
+
+      @spec serve(:gen_tcp.socket(), any()) :: no_return()
       def serve(client, state \\ []) do
+        Logger.debug("#{__MODULE__} serving client #{inspect(client)}")
+        serve_loop(client, init(state))
+      end
+
+      defp serve_loop(client, state) do
         {id, data} = Amethyst.Server.Generic.get_packet(client)
         Logger.debug("State: #{inspect(state)}")
         packet = deserialize(id, data)
@@ -60,10 +72,9 @@ require Logger
         if result != :ok do
           Logger.warning("Handler returned result #{result}")
         end
-        serve(client, state)
+        serve_loop(client, state)
       end
 
-
       def transmit(packet, client) do
         Logger.debug("Transmitting #{inspect(packet)}")
         data = serialize(packet)

lib/servers/handhsake.ex

@@ -23,7 +23,13 @@ defmodule Amethyst.Server.Handshake do
 
   alias Amethyst.Minecraft.Read
 
+  @impl true
+  def init(state) do
+    state
+  end
+
   ## DESERIALIZATION
+  @impl true
   # Handshake https://wiki.vg/Protocol#Handshake
   @spec deserialize(0, binary()) ::
           {:handshake, any(), any(), any(), :login | :status | :transfer}
@@ -42,18 +48,20 @@ defmodule Amethyst.Server.Handshake do
   end
 
   ## SERIALIZATION
+  @impl true
   def serialize(_) do
     raise RuntimeError, "No packets can be transmitted while still in the handshake stage!"
   end
 
   ## HANDLING
+  @impl true
   # Handshake https://wiki.vg/Protocol#Handshake
   @spec handle(any(), any(), any()) :: no_return()
-  def handle({:handshake, 767, addr, port, next}, client, _state) do
+  def handle({:handshake, 767, addr, port, next}, client, state) do
     Logger.info("Got handshake, version 767 on #{addr}:#{port}. Wants to move to #{next}")
     case next do
-      :status -> Amethyst.Server.Status.serve(client)
-      :login -> Amethyst.Server.Login.serve(client)
+      :status -> Amethyst.Server.Status.serve(client, state)
+      :login -> Amethyst.Server.Login.serve(client, state)
       _ -> raise RuntimeError, "Unhandled move to next mode #{next}"
     end
   end

lib/servers/login.ex

@@ -24,7 +24,13 @@ defmodule Amethyst.Server.Login do
   alias Amethyst.Minecraft.Read
   alias Amethyst.Minecraft.Write
 
+  @impl true
+  def init(state) do
+    state
+  end
+
   ## DESERIALIZATION
+  @impl true
   # Login Start https://wiki.vg/Protocol#Login_Start
   def deserialize(0x00, data) do
     {[name, uuid], ""} = Read.start(data) |> Read.string() |> Read.uuid() |> Read.stop()
@@ -66,6 +72,7 @@ defmodule Amethyst.Server.Login do
   end
 
   ## SERIALIZATION
+  @impl true
   # Disconnect (login) https://wiki.vg/Protocol#Disconnect_(login)
   def serialize({:disconnect, reason}) do
     Write.varint(0x00) <> Write.string(reason)
@@ -103,6 +110,7 @@ defmodule Amethyst.Server.Login do
   end
 
   ## HANDLING
+  @impl true
   # Login Start https://wiki.vg/Protocol#Login_Start
   def handle({:login_start, name, uuid}, client, state) do
     Logger.info("Logging in #{name} (#{uuid})")
@@ -118,7 +126,7 @@ defmodule Amethyst.Server.Login do
     {:ok, state}
   end
   def handle({:login_acknowledged}, client, state) do
-    Amethyst.Server.Configuration.serve(client)
+    Amethyst.Server.Configuration.serve(client, state)
     {:ok, state}
   end
   def handle(tuple, _, state) do

lib/servers/status.ex

@@ -24,7 +24,13 @@ defmodule Amethyst.Server.Status do
   alias Amethyst.Minecraft.Read
   alias Amethyst.Minecraft.Write
 
+  @impl true
+  def init(state) do
+    state
+  end
+
   ## DESERIALIZATION
+  @impl true
   # Status Request https://wiki.vg/Protocol#Status_Request
   def deserialize(0x00, _) do
     {:status_request}
@@ -39,6 +45,7 @@ defmodule Amethyst.Server.Status do
   end
 
   ## SERIALIZATION
+  @impl true
   # Status Response https://wiki.vg/Protocol#Status_Response
   def serialize({:status_response, data}) do
     Write.varint(0x00) <> Write.string(data)
@@ -51,6 +58,7 @@ defmodule Amethyst.Server.Status do
   end
 
   ## HANDLING
+  @impl true
   # Status Request https://wiki.vg/Protocol#Status_Request
   def handle({:status_request}, client, state) do
     # We want to make this more dynamic in the future, but this works for now