import 'package:flutter/foundation.dart';

import '../models/scooter_state.dart';

/// Result of a local scooter authentication attempt.
///
/// A missing response is deliberately NOT a value here: it surfaces as a
/// [TimeoutException] so callers can tell "wrong PIN" from "no answer".
enum AuthenticationResult {
  success,
  invalidCredential,
}

/// Base class for every supported scooter.
///
/// The current [state] is always available synchronously and the UI rebuilds
/// through [ListenableBuilder]. There is no replay problem because there is
/// no stream to miss.
abstract class Scooter extends ChangeNotifier {
  ScooterState get state;

  Future<void> connect();
  Future<void> disconnect();

  Future<AuthenticationResult> authenticate(String credential);

  Future<void> lock();
  Future<void> unlock();

  Future<void> setHeadlight(bool enabled);

  /// True only when the implementation holds enough fresh scooter state to
  /// build a safe control write AND control writes are enabled for this build.
  bool get canWrite;

  /// Disconnects and releases every resource. The object is unusable after.
  Future<void> disposeScooter();
}

/// Thrown into any pending operation when the BLE link drops underneath it.
class ScooterConnectionLostException implements Exception {
  const ScooterConnectionLostException([this.message = 'Connection to the scooter was lost']);
  final String message;
  @override
  String toString() => message;
}