nixos-config/modules/services/mpd.nix

{
  username,
  config,
  pkgs,
  ...
}:
{
  environment.systemPackages = with pkgs; [
    mpc
    mpdris2
    ncmpcpp
    rmpc
  ];

  services.mpd = {
    enable = true;
    musicDirectory = "/home/${username}/Music";
    playlistDirectory = "/home/${username}/Music/.playlists";
    extraConfig = ''
      restore_paused "yes"
      auto_update "yes"

      audio_output {
        type "pipewire"
        name "pipewire"
      }
    '';
    user = "${username}"; # PipeWire requires this as it runs as the normal user and mpd normally runs as a system user.

    # Optional:
    # network.listenAddress = "any"; # if you want to allow non-localhost connections
  };
  systemd.services.mpd.environment = {
    # see: https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/609
    XDG_RUNTIME_DIR = "/run/user/1000"; # User-id must match above user. MPD will look inside this directory for the PipeWire socket.
  };
}