dotfiles/nixng/modules/minecraft-curseforge.nix

{
  pkgs,
  lib,
  config,
  ...
}: let
  inherit
    (lib)
    mkEnableOption
    mkIf
    mkOption
    types
    getExe
    makeBinPath
    ;
  cfg = config.services.minecraft.curseforge;
in {
  options.services.minecraft.curseforge = {
    enable = mkEnableOption "Enable Minecraft server service.";

    modpackZip = mkOption {
      type = types.package;
    };

    modpackName = mkOption {
      type = types.str;
    };

    modpacksChHash = mkOption {
      type = types.str;
    };

    javaPackage = mkOption {
      type = types.package;
      default = pkgs.jdk17;
    };

    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 = [];
    };

    extraFixup = mkOption {
      type = types.lines;
      default = "";
    };
  };

  config = mkIf cfg.enable {
    services.minecraft.curseforge.serverPackage = let
      curseforgeFod = pkgs.stdenv.mkDerivation {
        pname = "minecraft-curseforge-${cfg.modpackName}";
        version = "unknown";

        outputHashMode = "recursive";
        outputHashAlgo = "sha256";
        outputHash = cfg.modpacksChHash;

        buildInputs = with pkgs; [unzip curl which cacert cfg.javaPackage];

        src = cfg.modpackZip;

        phases = ["installPhase" "fixupPhase "];

        installPhase = ''
          mkdir -p $out/
          cp $src/server-setup-config.yaml $out/
          cd $out/
          sh -vx $src/start-server.sh install
          rm installer.jar.log
          rm -r libraries/net/minecraft/server
          # libraries/net/minecraft/server/1.16.5-20210115.111550/server-1.16.5-20210115.111550-srg.jar
        '';

        meta.license = with lib.licenses; unfree;
      };
    in
      pkgs.writeShellScriptBin "minecraft-curseforge-unknown" ''
        export PATH="${makeBinPath (with pkgs; [curl cfg.javaPackage yq])}:$PATH"
        echo minecraft booting

        function cleanup() {
          echo "minecraft cleaning up..."
          kill -TERM $_server
          while kill -0 $_server ; do
            wait "$_server"
          done
          echo "minecraft server exited..."
          ${getExe pkgs.symlink-state} destroy ${curseforgeFod} $PWD
          exit 0
        }
        trap cleanup TERM


        RW_PATHS=config:defaultconfigs ${getExe pkgs.symlink-state} setup ${curseforgeFod} $PWD

        MC_VERSION="$(yq -r '.install.mcVersion' ${curseforgeFod}/server-setup-config.yaml)"
        INSTALLER_URL="$(yq -r '.install.installerUrl' ${curseforgeFod}/server-setup-config.yaml)"
        LOADER_VERSION="$(yq -r '(.minecraft.modLoaders[] | select(.primary) | .).id' ${curseforgeFod}/manifest.json | cut -d '-' -f 2)"
        START_FILE="$(yq -r '.launch.startFile' ${curseforgeFod}/server-setup-config.yaml | sed -e 's/{{@mcversion@}}/'"$MC_VERSION/g" -e 's/{{@loaderversion@}}/'"$LOADER_VERSION/g" -)"
        START_COMMAND="$(yq -r '.launch.startCommand | join(" ")' ${curseforgeFod}/server-setup-config.yaml | sed -e 's/{{@startFile@}}/'"$START_FILE/g" -)"
        JAVA_ARGS="$(yq -r '.launch.javaArgs | join(" ")' ${curseforgeFod}/server-setup-config.yaml)"

        curl -L "$(sed -e 's/{{@loaderversion@}}/'"$LOADER_VERSION/g" -e 's/{{@mcversion@}}/'"$MC_VERSION/g" - <<<"$INSTALLER_URL")" -o forge-installer.jar

        java -jar forge-installer.jar --installServer >/dev/null 2>&1
        java $START_COMMAND $JAVA_ARGS &
        _server="$!"
        wait "$_server"
      '';

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

        mkdir -p /var/lib/minecraft/forge
        cd /var/lib/minecraft/forge
        echo "eula=true" > eula.txt
        exec ${getExe cfg.serverPackage}
      '';
      enabled = true;
    };

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