{ lib, pkgs, ... }: {

  users.groups.gandalf = { gid = 1000; };

  users.users.gandalf = {
    isNormalUser = true;
    home = "/home/gandalf";
    createHome = true;
    group = "gandalf";
    extraGroups = [ "wheel" ];
    shell = pkgs.zsh;
  };

  programs.zsh = {
    enable = true;
    ohMyZsh = {
      enable = true;
      theme = "half-life";
    };
    syntaxHighlighting.enable = true;
    enableCompletion = true;
    autosuggestions.enable = true;
    shellAliases = {
      ls = "${pkgs.eza}/bin/eza --group-directories-first --hyperlink --icons";
      la =
        "${pkgs.eza}/bin/eza --group-directories-first --hyperlink --icons -la";
      ll =
        "${pkgs.expect}/bin/unbuffer ${pkgs.eza}/bin/eza --group-directories-first --hyperlink --icons -la | ${pkgs.less}/bin/less -r";
      lt =
        "${pkgs.eza}/bin/eza --group-directories-first --hyperlink --icons -la --tree";
      llt =
        "${pkgs.expect}/bin/unbuffer ${pkgs.eza}/bin/eza --group-directories-first --hyperlink --icons -la --tree | ${pkgs.less}/bin/less -r";
      sa = ''
        if ps -p $SSH_AGENT_PID > /dev/null 2>&1; then ${pkgs.gum}/bin/gum log -l info "ssh-agent is already running: pid: $SSH_AGENT_PID"; else eval $(ssh-agent); ssh-add ~/.ssh/id_ed25519; ${pkgs.gum}/bin/gum log -l info "ssh-agent started"; fi'';
    };
  };

  environment.systemPackages = [
    (pkgs.writeShellScriptBin "n" ''
      set -euo pipefail

      action=$(${pkgs.gum}/bin/gum choose --header "Choose action:" build clean)
      target=$(${pkgs.gum}/bin/gum choose --header "Choose target:" PABU APPA MOMO)

      case "$target" in
        "PABU")
          ;;
        *)
          if ! ps -p $SSH_AGENT_PID > /dev/null; then
            ${pkgs.gum}/bin/gum log -t kitchen -l error "ssh-agent is not running! Please run \"sa\". Exiting ..."
            exit 1
          fi
          ${pkgs.rsync}/bin/rsync -r . $target:/root/nix/
          ;;
      esac

      case "$action" in
        "clean")
          case "$target" in
            "PABU")
              ${pkgs.gum}/bin/gum log -t kitchen -l info "Running: sudo nix-collect-garbage -d && nix store gc && nix-store --optimise"
              sudo nix-collect-garbage -d && nix store gc && nix-store --optimise
              ;;
            *)
              ${pkgs.gum}/bin/gum log -t kitchen -l info "Running: ssh $target \"nix-collect-garbage -d && nix store gc && nix-store --optimise\""
              ssh $target "nix-collect-garbage -d && nix store gc && nix-store --optimise"
              ;;
          esac
          ;;
        "build")
          case "$target" in
            "PABU")
              sudo nixos-rebuild build --option sandbox false --log-format internal-json -v --flake .#PABU |& ${pkgs.nix-output-monitor}/bin/nom --json
              ${pkgs.nvd}/bin/nvd --color=always diff /run/current-system result
              postBuildAction=$(${pkgs.gum}/bin/gum choose --header "Choose post-build-action" skip switch boot test )
              case "$postBuildAction" in
                "skip")
                  ${pkgs.gum}/bin/gum log -t kitchen -l info "Skipping ..."
                  ;;
                *)
                  sudo ./result/bin/switch-to-configuration $postBuildAction
                  ;;
              esac
              ;;
            *)
              ssh $target "cd /root/nix; nixos-rebuild build --log-format internal-json -v --flake .#$target" |& ${pkgs.nix-output-monitor}/bin/nom --json
              ssh $target "cd /root/nix; nix run nixpkgs#nvd -- --color=always diff /run/current-system result"
              postBuildAction=$(${pkgs.gum}/bin/gum choose --header "Choose post-build-action" skip switch boot test )
              case "$postBuildAction" in
                "skip")
                  ${pkgs.gum}/bin/gum log -t kitchen -l info "Skipping ..."
                  ;;
                *)
                  ssh $target "cd /root/nix; ./result/bin/switch-to-configuration $postBuildAction"
                  ;;
              esac
              ;;
          esac
          ;;
        *)
          ${pkgs.gum}/bin/gum log -t kitchen -l error "Unkown action: $action. Exiting ..."
          exit 1
          ;;
      esac
    '')
  ];

}