{
  symlinkJoin,
  writeShellApplication,
  nvd,
  nix-output-monitor,
}: let
  deploy = writeShellApplication {
    name = "deploy";
    text = ''
                 	set -euo pipefail

                 function die { echo "error: $*" >&2; exit 1;}
                 function show_help() {
                 	echo ' Usage: deploy [OPTIONS] <system[@host],...> [ACTION]'
      echo ' Deploy a system as defined in the current flakes nixosSystem'
      echo ' If host is not given use the system name as host'
      echo ""
                 	echo 'ACTION:'
                 	echo '  switch			[default] build, push and switch to the new configuration'
                 	echo '  boot			switch on next boot'
                 	echo '  test			switch to config but do not make it the boot default'
                 	echo '  dry-activate	just show what an activation would do'
                 	echo ""
                 	echo 'OPTIONS:'
                 	echo '  --help		show this help menu'
                 }

                 	USER_FLAKE_DIR=$(git rev-parse --show-toplevel 2>/dev/null || pwd) \
                 || die "Could not determine current directory"

                 cd "$USER_FLAKE_DIR"

                 [[ $# -gt 0 ]] || {
                 	show_help
                 	exit 1
                 }

                 OPTIONS=()
                 POSITIONAL_ARGS=()
                 while [[ $# -gt 0 ]]; do
                 case "$1" in
                 	"help"|"--help"|"-h")
                 		show_help
                 		exit 1
                 		;;
                 	-*)
                 		OPTIONS+=("$1")
                 		;;
                 	*)
                 		POSITIONAL_ARGS+=("$1")
                 	esac
                 	shift
                 done

                 [[ ! ''${#POSITIONAL_ARGS[@]} -lt 1 ]] \
                 || die "Missing argument: <hosts,...>"
                 [[ ! ''${#POSITIONAL_ARGS[@]} -gt 2 ]] \
                 || die "Too many arguments"

                 shopt -s lastpipe
                 tr , '\n' <<< "''${POSITIONAL_ARGS[0]}" | sort -u | readarray -t HOSTS

                 ACTION="''${POSITIONAL_ARGS[1]-switch}"

                 function main() {
        local system
        local host
        if [[ $1 == *"@"* ]]; then
        	arr=()
        	echo -n "$1" | readarray -d "@" -t arr
        	system="''${arr[0]}"
        	host="root@''${arr[1]}"
        else
        	system=$1
        	host=$system
        fi
                 	local config
                 	config=".#nixosConfigurations.$system.config.system.build.toplevel"
                 	local top_level
        exec > >(trap "" INT TERM; sed "s/^/$system: /")
        exec 2> >(trap "" INT TERM; sed "s/^/$system: /" >&2)
                     top_level=$(nix build --no-link --print-out-paths "''${OPTIONS[@]}" "$config" || die "Failed building derivation for $system"  )

                 	echo -e "Copying toplevel for \033[0;32m$system\033[0m"
                     nix copy --to "ssh://$host" "$top_level" \
                 	|| die "Failed copying closure to $system"

                 	echo -e "Applying toplevel for \033[0;32m$system\033[0m"
             (
          prev_system=$(ssh "$host" -- readlink -e /nix/var/nix/profiles/system)
                 	ssh "$host" -- /run/current-system/sw/bin/nix-env --profile /nix/var/nix/profiles/system --set "$top_level" \
                 	|| die "Error registering toplevel $system"
                 	ssh "$host" -- "$top_level/bin/switch-to-configuration" "$ACTION" \
                 	|| die "Error activating toplevel for $system"
          if [[ -n "$prev_system" ]]; then
                 ssh "$host" -- ${nvd}/bin/nvd --color always diff "$prev_system" "$top_level"
               fi
             )
                 }

                 echo -e "Building toplevels for \033[0;32m''${#HOSTS[*]} hosts\033[0m"

                 for host in "''${HOSTS[@]}"; do
                 	main "$host" &
                 done
                 wait
    '';
  };
  build = writeShellApplication {
    name = "build";
    text = ''
      	set -euo pipefail

      function die { echo "error: $*" >&2; exit 1;}
      function show_help() {
      	echo ' Usage: build [OPTIONS] <host,...>'
      	echo 'Build the toplevel nixos configuration for hosts'
      }

      	USER_FLAKE_DIR=$(git rev-parse --show-toplevel 2>/dev/null || pwd) \
      || die "Could not determine current directory"

      cd "$USER_FLAKE_DIR"

      [[ $# -gt 0 ]] || {
      	show_help
      	exit 1
      }

      OPTIONS=()
      POSITIONAL_ARGS=()
      while [[ $# -gt 0 ]]; do
      case "$1" in
      	"help"|"--help"|"-h")
      		show_help
      		exit 1
      		;;
      	-*)
      		OPTIONS+=("$1")
      		;;
      	*)
      		POSITIONAL_ARGS+=("$1")
      		;;
      	esac
      	shift
      done

      [[ ! ''${#POSITIONAL_ARGS[@]} -lt 1 ]] \
      || die "Missing argument: <hosts,...>"
      [[ ! ''${#POSITIONAL_ARGS[@]} -gt 1 ]] \
      || die "Too many arguments"

      shopt -s lastpipe
      tr , '\n' <<< "''${POSITIONAL_ARGS[0]}" | sort -u | readarray -t HOSTS

      NIXOS_CONFIGS=()
      for host in "''${HOSTS[@]}"; do
      	NIXOS_CONFIGS+=(".#nixosConfigurations.$host.config.system.build.toplevel")
      done


      echo -e "Building toplevels for \033[0;32m''${#HOSTS[*]} hosts\033[0m"
      ${nix-output-monitor}/bin/nom build --print-out-paths --no-link "''${OPTIONS[@]}" "''${NIXOS_CONFIGS[@]}" \
      || die "Failed building derivations"

    '';
  };
in
  symlinkJoin {
    name = "deploy and build";
    paths = [deploy build];
  }