typedef CacheScopeProvider = String? Function();

class CacheScope {
  CacheScope._();

  static CacheScopeProvider? _provider;

  static void configureProvider(CacheScopeProvider provider) {
    _provider = provider;
  }

  static void resetProvider() {
    _provider = null;
  }

  static String token() {
    final value = maybeToken();
    if (value == null) {
      throw StateError('CacheScope not configured - user must be logged in');
    }
    return value;
  }

  static String? maybeToken() {
    final raw = _provider?.call()?.trim();
    if (raw == null || raw.isEmpty) {
      return null;
    }
    return raw;
  }

  static String scopedKey(String key, {String? scopeToken}) {
    final scope = scopeToken ?? token();
    return 'cache:$scope:$key';
  }
}