enum GopherType {
  Text,
  Directory,
  Error,
  Search,
  Url,
  Image,
}

class GopherPath {
  String _selector;
  GopherType _type;

  GopherPath(String path) {
    if (path.substring(0,1) != "/")
      throw "Path does not start with /<type>";
    switch (path.substring(1,2)) {
      case "0":
        _type = GopherType.Text;
        break;
      case "1":
        _type = GopherType.Directory;
        break;
      case "3":
        _type = GopherType.Error;
        break;
      case "7":
        _type = GopherType.Search;
        break;
      case "h":
        _type = GopherType.Url;
        break;
      case "g":
      case "G":
      case "i":
      case "I":
      case "p": // this isn't in the RFC, what's going on??
      case "P":
        _type = GopherType.Image;
        break;
      default:
        throw "Unknown type {path.substring(1,2)} encountered";
    }
    if (path.length > 2)
      _selector = path.substring(2);
    else
      _selector = "";
  }

  String get selector => _selector;
  GopherType get type => _type;
}

String generateGopherTitle(Uri uri) {
  var path = GopherPath(uri.path);
  return (path.selector.length != 0 ? "${path.selector} @ " : "") +
    uri.host + (uri.port != 70 && uri.port != 0  ? ":${uri.port}" : "");
}

Uri parseWeakInput(String s) {
  var uri = Uri.parse(s);
  if (!uri.hasScheme) {
    uri = Uri.parse("gopher://" + s);
  }
  if (uri.path.isEmpty) {
    uri = uri.replace(path: "/1");
  }
  if (uri.port == 0)
    uri = uri.replace(port: 70);
  return uri;
}