emacs.nix

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

with lib;
let
  cfg = config.services.emacs;
  package = config.programs.emacs.finalPackage;
in {
  options.services.emacs.enable = mkEnableOption "Emacs";

  config = mkIf cfg.enable {
    assertions = [
      {
        assertion = config.programs.emacs.enable;
        message = "Must enable programs.emacs.enable.";
      }
    ];

    systemd.user.services.emacs = {
      Unit = {
        Description = "Emacs: the extensible, self-documenting text editor";
        Documentation = "info:emacs man:emacs(1) https://gnu.org/software/emacs/";
      };

      Service = {
        Type = "simple";
        ExecStart = "${pkgs.stdenv.shell} -l -c 'exec ${package}/bin/emacs --fg-daemon'";
        ExecStop = "${package}/bin/emacsclient --eval '(kill-emacs)'";
        Restart = "on-failure";
      };

      Install = {
        WantedBy = [ "default.target" ];
      };
    };
  };
}