{ nixpkgs, ... }:

let
  lib = nixpkgs.lib;

  eachSystem =
    fn: lib.genAttrs lib.systems.flakeExposed (system: fn (import nixpkgs { inherit system; }));

  mkModpack =
    builder:
    let
      mkPackages =
        pkgs:
        let
          bootstrap = pkgs.fetchurl {
            url = "https://github.com/packwiz/packwiz-installer-bootstrap/releases/download/v0.0.3/packwiz-installer-bootstrap.jar";
            sha256 = "qPuyTcYEJ46X9GiOgtPZGjGLmO/AjV2/y8vKtkQ9EWw=";
          };

          buildInfo = builder pkgs.system;
        in
        lib.trace buildInfo {
          server = pkgs.writeShellScriptBin "minecraft-server" ''
            ${lib.getExe pkgs.jre} -jar ${bootstrap} -g -s server ${buildInfo.packUrl}
            # ${buildInfo.server}/bin/minecraft-server
          '';
        };

      overlay = final: prev: mkPackages prev;
    in
    {
      inherit overlay;
      packages = eachSystem mkPackages;
      devShells = eachSystem (pkgs: {
        default = pkgs.mkShell {
          buildInputs = with pkgs; [
            packwiz
          ];
        };
      });
    };
in
mkModpack