{ config, lib, pkgs, ... }:
let cfg = config.my.services.transmission;
in {
  options.my.services.transmission = with lib; {
    enable = mkEnableOption "transmission torrent server";
  };

  config = lib.mkIf cfg.enable {
    services.transmission = {
      enable = true;
      group = "nas";
      performanceNetParameters = true;
      home = "/data/fast/torrents";
      settings = {
        dht-enabled = false;
        cache-size-mb = 128;
        peer-port = 52213;
        peer-port-random-low = 49152;
        peer-port-random-high = 65535;
        message-level = 2;

        rpc-enabled = true;
        rpc-host-whitelist-enabled = false;
        verify-threads = 4;
      };
    };

    networking.firewall = {
      allowedTCPPorts = [ 52213 ];
      allowedUDPPorts = [ 52213 ];
    };
  };
}