public async Task <bool> AddBookToSubscription(int subscriptionId, int bookId)
{
var book = _bookRepository.GetBook(bookId);
var subscription = _subscriptionRepository.GetSubscriptionBySubscriptionId(subscriptionId);
// if book already exists in subscription AND subscription does not exist
if (book != null && subscription == null)
{
return(false);
}
return(await _bookRepository.AddBookToSubscription(subscriptionId, bookId));
}
