/// Base exception for all application errors.
sealed class AppException implements Exception {
  const AppException({required this.message, this.cause});

  final String message;
  final Object? cause;

  @override
  String toString() => 'AppException: $message';
}

/// Network-related errors (connection, timeout, etc.)
class NetworkException extends AppException {
  const NetworkException({required super.message, super.cause});
}

/// API errors with HTTP status codes.
class ApiException extends AppException {
  const ApiException({
    required super.message,
    required this.statusCode,
    this.code,
    super.cause,
  });

  final int statusCode;
  final String? code;

  bool get isUnauthorized => statusCode == 401;
  bool get isForbidden => statusCode == 403;
  bool get isNotFound => statusCode == 404;
  bool get isServerError => statusCode >= 500;
}

/// Authentication-related errors.
class AuthException extends AppException {
  const AuthException({required super.message, super.cause});
}

/// Cache/storage errors.
class CacheException extends AppException {
  const CacheException({required super.message, super.cause});
}

/// Validation errors.
class ValidationException extends AppException {
  const ValidationException({
    required super.message,
    this.fieldErrors = const {},
  });

  final Map<String, String> fieldErrors;
}