Complete doWork method for more complex scenario

DoWorkCompleteMoreComplex.kt

fun doWork(): Result<Unit> {
  return input() into
    ::parse elseIf
    {
      return Failure("Cannot parse email")
    } into
    ::validate elseIf
    {
      InvalidEmailAddress { message -> return Failure(message) }
      EmptySubject(::fixEmptySubject)
      EmptyBody { message -> return Failure(message) }
    } into
    ::send elseIf
    {
      IOFailure { error -> return Failure(error.message ?: "") }
      Timeout { error -> return Failure(error.message ?: "") }
      UnAuthorized { validatedEmail, _ ->
        validatedEmail into
          ::authorizeAndSend elseIf
          {
            return Failure(it)
          } into
          { SendSuccess(validatedEmail.email) }
      }
    } into
    { Success(Unit) }
}