export const createApiKeyGuard = (header: string, getValidKeys: () => string[]): Type<CanActivate> => {
  @Injectable()
  class ApiKeyGuardMixin implements CanActivate {
    canActivate(context: ExecutionContext): boolean {
      const request = context.switchToHttp().getRequest();
      const apiKey = request.headers[header];

      if (!apiKey) {
        throw new UnauthorizedException();
      }

      if (getValidKeys().includes(apiKey)) {
        return true;
      }

      throw new UnauthorizedException();
    }
  }

  return mixin(ApiKeyGuardMixin);
};