{
  config,
  lib,
  pkgs,
  ...
}:
let
  cfg = config.feature.cli;
in
{
  options.feature.cli = {
    enable = lib.mkEnableOption "Set up the CLI";
  };

  config = lib.mkIf cfg.enable {
    home.packages = with pkgs; [
      starship
      tree
    ];

    programs.fish = {
      enable = true;
      functions.fish_greeting = "";
      shellInitLast = lib.mkIf (lib.strings.hasSuffix "darwin" pkgs.system) ''
        eval $(/opt/homebrew/bin/brew shellenv)
      '';
    };

    programs.fzf = {
      enable = true;
      enableFishIntegration = true;
    };

    programs.zsh = lib.mkIf (lib.strings.hasSuffix "darwin" pkgs.system) {
      enable = true;

      # zsh is a POSIX compliant shell and a safe default, but if it's an interactive
      # shell and fish is not in the parent processes (i.e. I'm not deliberately starting
      # zsh to use interactively from fish) then just launch fish.
      initContent = ''
        [[ $- == *i* ]] || return

        is_parent_fish() {
          local ppid=$$
          while [[ $ppid -ne 1 ]]; do
            local ppname=$(ps -p $ppid -o comm=)
            if [[ "$ppname" == *fish* ]]; then
              return 1
            fi
            ppid=$(ps -o ppid= -p $ppid)
          done
          return 0
        }

        if is_parent_fish
        then
          exec fish -l
        fi
      '';
    };

    programs.starship = {
      enable = true;
      enableFishIntegration = true;
      enableInteractive = true;
      enableTransience = true;
      settings = builtins.fromTOML (builtins.readFile ./starship.toml);
    };
  };
}