Begin work on data generator

apps/amethyst/lib/datagen.ex

@@ -0,0 +1,45 @@
+# Amethyst - An experimental Minecraft server written in Elixir.
+# Copyright (C) 2024 KodiCraft
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+defmodule Amethyst.DataGenerator do
+  @moduledoc """
+  This module allows Amethyst to download the vanilla Minecraft server and generate
+  necessary data files.
+  """
+  @spec get_version_meta(String.t() | :latest) :: {:ok, map()} | {:error, term}
+  def get_version_meta(version) do
+    version = if version == :latest, do: get_latest_version(), else: {:ok, version}
+    case version do
+      {:ok, version} ->
+        case Req.get(Application.fetch_env!(:amethyst, :mojang_game_meta)) do
+          {:ok, %{body: %{"versions" => versions}}} ->
+            case Enum.find(versions, fn %{"id" => id} -> id == version end) do
+              nil -> {:error, :version_not_found}
+              version_meta -> {:ok, version_meta}
+            end
+          {:error, err} -> {:error, err}
+        end
+      {:error, err} -> {:error, err}
+    end
+  end
+
+  def get_latest_version() do
+    case Req.get(Application.fetch_env!(:amethyst, :mojang_game_meta)) do
+      {:ok, %{body: %{"latest" => %{"release" => release}}}} -> {:ok, release}
+      {:error, err} -> {:error, err}
+    end
+  end
+end

config/config.exs

@@ -12,3 +12,7 @@ import Config
     level: :debug,
     format: "$date $time [$level] $metadata$message\n",
     metadata: []
+
+  config :amethyst,
+    mojang_game_meta: "https://piston-meta.mojang.com/mc/game/version_manifest_v2.json",
+    session_server: "https://sessionserver.mojang.com"

config/runtime.exs

@@ -4,7 +4,6 @@ config :amethyst,
   port: 25599, # Bogus port for testing, avoids unexpected conflicts
   encryption: true, # Whether or not to request encryption from clients.
   auth: true, # Whether or not users should be authenticated with Mojang.
-  session_server: "https://sessionserver.mojang.com", # Base URL to the Mojang session server
   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
   release: config_env() == :prod # If this is set to false, Amethyst will perform additional checks at runtime and will handle errors more loosely