nix-darwin/modules/security/pam.nix

{ config, lib, pkgs, ... }:

let
  cfg = config.security.pam.services.sudo_local;
in
{
  imports = [
    (lib.mkRemovedOptionModule [ "security" "pam" "enableSudoTouchIdAuth" ] ''
      This option has been renamed to `security.pam.services.sudo_local.touchIdAuth` for consistency with NixOS.
    '')
  ];

  options = {
    security.pam.services.sudo_local = {
      enable = lib.mkEnableOption "managing {file}`/etc/pam.d/sudo_local` with nix-darwin" // {
        default = true;
        example = false;
      };

      text = lib.mkOption {
        type = lib.types.lines;
        default = "";
        description = ''
          Contents of {file}`/etc/pam.d/sudo_local`
        '';
      };

      touchIdAuth = lib.mkEnableOption "" // {
        description = ''
          Whether to enable Touch ID with sudo.

          This will also allow your Apple Watch to be used for sudo. If this doesn't work,
          you can go into `System Settings > Touch ID & Password` and toggle the switch for
          your Apple Watch.
        '';
      };
    };
  };

  config = {
    security.pam.services.sudo_local.text = lib.optionalString cfg.touchIdAuth "auth       sufficient     pam_tid.so";

    environment.etc."pam.d/sudo_local" = {
      inherit (cfg) enable text;
    };

    system.activationScripts.pam.text =
    let
      file = "/etc/pam.d/sudo";
      marker = "security.pam.services.sudo_local";
      deprecatedOption = "security.pam.enableSudoTouchIdAuth";
      sed = lib.getExe pkgs.gnused;
    in
    ''
      # PAM settings
      echo >&2 "setting up pam..."

      # REMOVEME when macOS 13 no longer supported as macOS automatically
      # nukes this file on system upgrade
      # Always clear out older implementation if it is present
      if grep '${deprecatedOption}' ${file} > /dev/null; then
        ${sed} -i '/${deprecatedOption}/d' ${file}
      fi

      ${if cfg.enable then ''
        # REMOVEME when macOS 13 no longer supported
        # `sudo_local` is automatically included after macOS 14
        if ! grep 'sudo_local' ${file} > /dev/null; then
          ${sed} -i '2iauth       include        sudo_local # nix-darwin: ${marker}' ${file}
        fi
      '' else ''
        # Remove include line if we added it
        if grep '${marker}' ${file} > /dev/null; then
          ${sed} -i '/${marker}/d' ${file}
        fi
      ''}
    '';
  };
}