{
  description = "Example Darwin system flake";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    # home-manager.url = "github:nix-community/home-manager/master";
    # home-manager.inputs.nixpkgs.follows = "nixpkgs";
    nix-darwin.url = "github:LnL7/nix-darwin";
    nix-darwin.inputs.nixpkgs.follows = "nixpkgs";
  };

  outputs = inputs@{ self, nix-darwin, nixpkgs }:
    let
      configuration = { pkgs, ... }: {
        # List packages installed in system profile. To search by name, run:
        # $ nix-env -qaP | grep wget
        environment.systemPackages =
          with pkgs; [
            neovim
            bat
            ripgrep
            fd

            fish
            nushellFull

            tmux
            wezterm
            # yabai
            nerdfonts
          ];



        # Auto upgrade nix package and the daemon service.
        services.nix-daemon.enable = true;
        # nix.package = pkgs.nix;

        # Necessary for using flakes on this system.
        nix = {
          settings = {
            experimental-features = "nix-command flakes repl-flake";
            max-jobs = 8;
          };
          extraOptions = ''
            build-users-group = nixbld
            extra-nix-path = nixpkgs=flake:nixpkgs
          '';
          # keep-outputs = true
          # keep-derivations = true
        };


        # Create /etc/zshrc that loads the nix-darwin environment.
        # programs.zsh.enable = true;  # default shell on catalina
        # programs.fish.enable = true;

        # Set Git commit hash for darwin-version.
        system.configurationRevision = self.rev or self.dirtyRev or null;
        system.keyboard.enableKeyMapping = true;
        system.keyboard.remapCapsLockToControl = true;
        system.keyboard.swapLeftCommandAndLeftAlt = true;
        system.keyboard.userKeyMapping = {
            # Right Command to Option
            HIDKeyboardModifierMappingSrc = 30064771303;
            HIDKeyboardModifierMappingDst = 30064771302;
            # Right Option to command
            HIDKeyboardModifierMappingSrc = 30064771302;
            HIDKeyboardModifierMappingDst = 30064771303;
        };
        fonts.fonts = [ (pkgs.nerdfonts.override { fonts = [ "Hasklig" "Hack" ]; }) ];
        system.defaults.finder.AppleShowAllExtensions = true;
        system.defaults.dock.autohide = true;

        # Used for backwards compatibility, please read the changelog before changing.
        # $ darwin-rebuild changelog
        system.stateVersion = 4;

        # The platform the configuration will be used on.
        nixpkgs.hostPlatform = "aarch64-darwin";

        nix.package = pkgs.nix;

      };
    in
    {
      # Build darwin flake using:
      # $ darwin-rebuild build --flake .#simple
      darwinConfigurations.Uttarayans-MacBook-Pro = nix-darwin.lib.darwinSystem {
        # system = "aarch64-darwin";
        pkgs = import nixpkgs { system = "aarch64-darwin"; };
        modules = [ configuration ];
      };

      # Expose the package set, including overlays, for convenience.
      darwinPackages = self.darwinConfigurations.Uttarayans-MacBook-Pro.pkgs;
    };
}