{
  description = "mat's nix configs";

  inputs = {
    # base inputs
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    flake-parts.url = "github:hercules-ci/flake-parts";
    nix-darwin.url = "github:lnl7/nix-darwin/master";
    nix-darwin.inputs.nixpkgs.follows = "nixpkgs";
    home-manager.url = "github:nix-community/home-manager";
    home-manager.inputs.nixpkgs.follows = "nixpkgs";
    nixos-flake.url = "github:srid/nixos-flake";
    pre-commit.url = "github:cachix/pre-commit-hooks.nix";
    pre-commit.inputs.nixpkgs.follows = "nixpkgs";
    disko.url = "github:nix-community/disko";
    disko.inputs.nixpkgs.follows = "nixpkgs";
    ghostty.url = "github:clo4/ghostty-hm-module";
    mac-app-util.url = "github:hraban/mac-app-util";
    mac-app-util.inputs.nixpkgs.follows = "nixpkgs";

    # "flag" for toggling homebrew operations
    # https://www.mat.services/posts/command-line-flake-arguments/
    homebrew-enabled.url = "github:boolean-option/true";

    # command line text editor
    helix.url = "github:helix-editor/helix";
    helix.inputs.nixpkgs.follows = "nixpkgs";

    # nix language servers
    nil.url = "github:oxalica/nil";
    nil.inputs.nixpkgs.follows = "nixpkgs";
    nixd.url = "github:nix-community/nixd";
    nixd.inputs.nixpkgs.follows = "nixpkgs";

    # iA writer fonts
    ia-writer-family-src.url = "github:iaolo/iA-Fonts";
    ia-writer-family-src.flake = false;

    # standard kitty terminal themes
    terminal-themes.url = "github:mbadolato/iTerm2-Color-Schemes";
    terminal-themes.flake = false;

    # shell prompt
    starship-src.url = "github:starship/starship";
    starship-src.flake = false;

    # extra fish shell plugins
    fish-plugin-done.url = "github:franciscolourenco/done";
    fish-plugin-done.flake = false;
    fish-plugin-fish-abbr-tips.url = "github:Gazorby/fish-abbreviation-tips";
    fish-plugin-fish-abbr-tips.flake = false;
    fish-plugin-autopair.url = "github:jorgebucaran/autopair.fish";
    fish-plugin-autopair.flake = false;
    fish-plugin-replay.url = "github:jorgebucaran/replay.fish";
    fish-plugin-replay.flake = false;
    fish-plugin-fish-bang-bang.url = "github:oh-my-fish/plugin-bang-bang";
    fish-plugin-fish-bang-bang.flake = false;
    fish-plugin-colored-man-pages.url =
      "github:PatrickF1/colored_man_pages.fish";
    fish-plugin-colored-man-pages.flake = false;
  };

  outputs = { self, flake-parts, ... }@inputs:
    flake-parts.lib.mkFlake { inherit inputs; } {
      systems = [ "aarch64-darwin" "aarch64-linux" ];
      imports = [
        inputs.nixos-flake.flakeModule
        inputs.pre-commit.flakeModule
        ./darwin
        ./home
        ./nixos
        ./templates
        ./users
      ];
      flake = {
        nixosConfigurations = {
          # pihole = self.nixos-flake.lib.mkLinuxSystem {
          #   nixpkgs.hostPlatform = "aarch64-linux";
          #   imports = [ self.nixosModules.default ./systems/nixos/pihole.nix ];
          # };
        };

        darwinConfigurations = {
          matbook = self.nixos-flake.lib.mkMacosSystem {
            nixpkgs.hostPlatform = "aarch64-darwin";
            imports = [
              self.darwinModules.default
              ./darwin/games.nix
              ./systems/darwin/m1.nix
            ];
          };

          yelpbook-m1 = self.nixos-flake.lib.mkMacosSystem {
            nixpkgs.hostPlatform = "aarch64-darwin";
            imports = [
              self.darwinModules.default
              ./systems/darwin/m1.nix
              ./systems/darwin/work.nix
            ];
          };
        };
      };
      perSystem = { self', pkgs, config, ... }:
        # formatter for this flake
        let formatter = pkgs.nixfmt;
        in {
          # controls which flake inputs are updated by `nix run .#update`
          nixos-flake.primary-inputs = [
            # system inputs
            "nixpkgs"
            "flake-parts"
            "nix-darwin"
            "home-manager"
            "nixos-flake"
            # package inputs
            "helix"
            "nil"
            "nixd"
          ];

          pre-commit.settings.hooks = {
            deadnix.enable = true;
            nil.enable = true;
            nixfmt.enable = true;
            statix.enable = true;
          };

          # TODO: how to set legacy packages with overrides, etc?
          packages.default = self'.packages.activate;
          devShells.default = pkgs.mkShell {
            shellHook = ''
              ${config.pre-commit.installationScript}
              echo 1>&2 "\(^ヮ^)/ welcome to the flake \(^ヮ^)/"
            '';
            buildInputs = [ formatter ];
          };
          inherit formatter;
        };
    };
}