{ pkgs, lib, config, ... }:
let cfg = config.openssh;
    inherit (lib) types;
in
{
  options.openssh = {
    enable = lib.mkEnableOption "OpenSSH shell utilities";
    sshConf = lib.mkOption {
      type = types.lines;
      apply = s: pkgs.writeText "ssh_config" s;
      default = ''
      '';
      description = ''
        OpenSSH's ssh_config content.
      '';
    };
  };
  config = lib.mkIf cfg.enable {
    nix-shell.buildInputs =
      let ssh = pkgs.writeShellScriptBin "ssh" ''
          ${pkgs.openssh}/bin/ssh -F ${cfg.sshConf} "$@"
        '';
      in
      [ ssh ];
  };
}