import 'package:shared_preferences/shared_preferences.dart';

/// Persisted user settings for the Ch∆In hub connection.
///
/// Stored under four SharedPreferences keys matching the Studio
/// convention (`hub.host`, `hub.port`, `hub.secure`, `hub.token`)
/// so a hub once configured stays configured across app launches.
/// Distinct from the SDK's `chain.HubEndpoint`, which is a
/// transport-level value type — [HubSettings.toEndpoint] adapts
/// in that direction.
class HubSettings {
  const HubSettings({
    required this.host,
    required this.port,
    required this.secure,
    this.authToken,
    this.useHub = false,
  });

  final String host;
  final int port;
  final bool secure;

  /// Bearer token; read from `~/.chain/hub-auth-token` by the
  /// hub-status page in Phase 1. Optional in Phase 0 because the
  /// default `chain serve` runs without auth.
  final String? authToken;

  /// User intent: try to connect to the hub on startup. False
  /// keeps the app in MockRepository mode regardless of host/port.
  final bool useHub;

  static const defaultHost = '127.0.0.1';
  static const defaultPort = 50051;

  String get scheme => secure ? 'https' : 'http';
  String get url => '$scheme://$host:$port';

  static const _kHost = 'hub.host';
  static const _kPort = 'hub.port';
  static const _kSecure = 'hub.secure';
  static const _kToken = 'hub.token';
  static const _kUseHub = 'hub.use';

  static Future<HubSettings> load() async {
    final prefs = await SharedPreferences.getInstance();
    return HubSettings(
      host: prefs.getString(_kHost) ?? defaultHost,
      port: prefs.getInt(_kPort) ?? defaultPort,
      secure: prefs.getBool(_kSecure) ?? false,
      authToken: prefs.getString(_kToken),
      useHub: prefs.getBool(_kUseHub) ?? false,
    );
  }

  Future<void> save() async {
    final prefs = await SharedPreferences.getInstance();
    await prefs.setString(_kHost, host);
    await prefs.setInt(_kPort, port);
    await prefs.setBool(_kSecure, secure);
    await prefs.setBool(_kUseHub, useHub);
    if (authToken != null) {
      await prefs.setString(_kToken, authToken!);
    } else {
      await prefs.remove(_kToken);
    }
  }

  HubSettings copyWith({
    String? host,
    int? port,
    bool? secure,
    String? authToken,
    bool? useHub,
  }) =>
      HubSettings(
        host: host ?? this.host,
        port: port ?? this.port,
        secure: secure ?? this.secure,
        authToken: authToken ?? this.authToken,
        useHub: useHub ?? this.useHub,
      );
}