{ pkgs, hosts, groups }:

with pkgs.lib;

(mapAttrs (name: hosts: ''
  #!${pkgs.runtimeShell}
  export PATH=
  nix build --no-link ${
    concatMapStringsSep " " (host:
      builtins.unsafeDiscardStringContext
      host.config.system.build.toplevel.drvPath) hosts
  }
  ${concatMapStrings (host: ''
    echo "deploying ${host.config.networking.hostName}..."
    ${host.config.system.build.deployScript} $1 &
    PID_LIST+=" $!"
  '') hosts}
  # FIXME: remove jobs from PIDLIST once they finish
  trap "kill $PID_LIST" SIGINT
  wait $PID_LIST
'') groups)
// (mapAttrs (name: host: host.config.system.build.deployScript) hosts)