{ config, lib, pkgs, ... }:

with lib;
let
  cfg = config.fudo.slynk;

  initScript = port: pkgs.writeText "slynk.lisp" ''
    (load (merge-pathnames "quicklisp/setup.lisp" (user-homedir-pathname)))
    (ql:quickload :slynk)
    (slynk:create-server :port ${toString port} :dont-close t)
    (dolist (var '("LD_LIBRARY_PATH"))
      (format t "~S: ~S~%" var (sb-unix::posix-getenv var)))

    (loop (sleep 60))
  '';

in {
  options.fudo.slynk = {
    enable = mkEnableOption "Enable Slynk emacs common lisp server.";

    port = mkOption {
      type = types.int;
      description = "Port on which to open a Slynk server.";
      default = 4005;
    };
  };

  config = mkIf cfg.enable {
    systemd.user.services.slynk = {
      description = "Slynk Common Lisp server.";

      serviceConfig = {
        # Type = "simple";
        ExecStartPre = "${pkgs.lispPackages.quicklisp}/bin/quicklisp init";
        ExecStart = "${pkgs.sbcl-with-libs}/bin/sbcl --load ${initScript cfg.port}";
        Restart = "on-failure";
        PIDFile = "/run/slynk.$USERNAME.pid";
      };

      environment = {
        LD_LIBRARY_PATH = "${pkgs.openssl_1_1.out}/lib:${pkgs.libuv.out}/lib";
      };

      ## Starts on login. But what about ports?
      # wantedBy = [ "default.target" ];
    };
  };
}