From 8b09c78f02793578f5a260e50240b7626c970537 Mon Sep 17 00:00:00 2001
From: Kodi Craft <kodi@kdcf.me>
Date: Sun, 6 Oct 2024 15:49:55 +0200
Subject: [PATCH] Actually implement compression

---
 apps/amethyst/lib/apps/connection_handler.ex  | 8 +++++---
 apps/amethyst/lib/apps/connection_receiver.ex | 2 +-
 config/runtime.exs                            | 2 +-
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/apps/amethyst/lib/apps/connection_handler.ex b/apps/amethyst/lib/apps/connection_handler.ex
index 60968d8..569e7ce 100644
--- a/apps/amethyst/lib/apps/connection_handler.ex
+++ b/apps/amethyst/lib/apps/connection_handler.ex
@@ -66,7 +66,7 @@ defmodule Amethyst.ConnectionHandler do
         loop(socket, connstate, version, state)
       {:set_compression, threshold} ->
         Logger.debug("Enabling comrpession with threshold #{threshold}")
-        state = Map.put(state, :compression_threshold, threshold)
+        state = Map.put(state, :compression, threshold)
         loop(socket, connstate, version, state)
       {:set_position, position} ->
         prev_position = Map.get(state, :position)
@@ -118,7 +118,7 @@ defmodule Amethyst.ConnectionHandler do
             send(from, Map.get(state, :decryption_state))
             loop(socket, connstate, version, state)
           {:get_compression, from} ->
-            send(from, Map.get(state, :compression_threshold))
+            send(from, Map.get(state, :compression))
             loop(socket, connstate, version, state)
           {:packet, id, data} ->
             state = handle_packet(id, data, connstate, version, state)
@@ -258,6 +258,7 @@ defmodule Amethyst.ConnectionHandler do
   defp send_packet(socket, connstate, packet, version, state) do
     try do
       data = connstate.serialize(packet, version)
+      Logger.debug("#{inspect(Map.get(state, :compression))}")
       container = if Map.get(state, :compression) == nil do
         # Packet ID is included in data
         Write.varint(byte_size(data)) <> data
@@ -265,13 +266,14 @@ defmodule Amethyst.ConnectionHandler do
         threshold = Map.get(state, :compression, 0)
         data_length = byte_size(data)
         if data_length >= threshold do
-          compressed = Write.varint(data_length) <> :zlib.zip(data)
+          compressed = Write.varint(data_length) <> :zlib.compress(data)
           Write.varint(byte_size(compressed)) <> compressed
         else
           compressed = Write.varint(0) <> data
           Write.varint(byte_size(compressed)) <> compressed
         end
       end
+      Logger.debug(inspect(container))
       encrypted = if Map.get(state, :encryption_state) == nil do
         container
       else
diff --git a/apps/amethyst/lib/apps/connection_receiver.ex b/apps/amethyst/lib/apps/connection_receiver.ex
index 08c591a..3b8e033 100644
--- a/apps/amethyst/lib/apps/connection_receiver.ex
+++ b/apps/amethyst/lib/apps/connection_receiver.ex
@@ -104,7 +104,7 @@ defmodule Amethyst.ConnectionReceiver do
                 rest
               else
                 # Compressed data
-                rest |> :zlib.unzip()
+                rest |> :zlib.uncompress()
               end
             end
 
diff --git a/config/runtime.exs b/config/runtime.exs
index acd79ea..a3c94b6 100644
--- a/config/runtime.exs
+++ b/config/runtime.exs
@@ -4,5 +4,5 @@ config :amethyst,
   port: 25599, # Bogus port for testing, avoids unexpected conflicts
   encryption: true, # Whether or not to request encryption from clients.
   auth: false, # Whether or not users should be authenticated with Mojang.
-  compression: nil, # Packets larger than this amount are sent compressed. Set to nil to disable compression.
+  compression: 256, # Packets larger than this amount are sent compressed. Set to nil to disable compression.
   default_game: Example.Game # Which game new players should be sent to