dotfiles/nixng/modules/minecraft.nix

{ pkgs, config, lib, ... }:
with lib;
let
  cfg = config.services.minecraft.vanilla;
in
{
  options.services.minecraft.vanilla = {
    enable = mkEnableOption "Enable Minecraft server service.";

    serverPackage = mkOption {
      type = types.package;
      readOnly = true;
    };

    eulaAccept = mkOption {
      type = with types; bool;
      description = ''
        By changing the setting below to true you are indicating your agreement to Mojang's EULA (https://account.mojang.com/documents/minecraft_eula).
      '';
      default = false;
    };

    extraJavaArguments = mkOption {
      type = with types; listOf str;
      default = [];
    };
  };

  config = mkIf cfg.enable {

    services.minecraft.vanilla.serverPackage =
      pkgs.stdenv.mkDerivation {
        pname = "minecraft";
        version = "unknown";

        src = pkgs.fetchurl {
          url = "https://piston-data.mojang.com/v1/objects/84194a2f286ef7c14ed7ce0090dba59902951553/server.jar";
          hash = "sha256-RIsU/6VxKZ7Sk59dgG4dudHhRLcD+ki32Ab0wv00Tik=";
          executable = true;
        };

        phases = [ "installPhase" ];

        installPhase = ''
          mkdir -p $out/bin

          ${lib.getExe pkgs.jdk17} -jar $src --initSettings
          mkdir -p $out/share
          cp server.properties $out/share/

          cp ${pkgs.writeShellScript "server.sh" ''
            [ -f server.properties ] || cp @out@/share/server.properties .
            ${lib.getExe pkgs.jdk17} "$@" -jar @src@
          ''} $out/bin/server
          substituteInPlace $out/bin/server --subst-var src --subst-var out
        '';
      };

    init.services.minecraft-vanilla = {
      script = pkgs.writeShellScript "minecraft-run" ''
        set -xe

        mkdir -p /var/lib/minecraft/vanilla
        cd /var/lib/minecraft/vanilla
        echo "eula=true" > eula.txt
        ${cfg.serverPackage}/bin/server ${concatMapStringsSep " " (x: ''"${x}"'') cfg.extraJavaArguments}
      '';
      enabled = true;
      shutdownOnExit = true;
    };

    assertions = [
      { assertion = cfg.eulaAccept;
        message = "You must accept the EULA";
      }
    ];
  };
}