public async Task <IActionResult> SetMainPhoto(int bookId, int id) { var book = await _repo.GetBook(bookId); if (!book.Photos.Any(p => p.Id == id)) { return(Unauthorized()); } var photoFromRepo = await _repo.GetPhoto(id); if (photoFromRepo.IsMain) { return(BadRequest("This is already the main photo")); } var currentMainPhoto = await _repo.GetMainPhotoForBook(bookId); currentMainPhoto.IsMain = false; photoFromRepo.IsMain = true; if (await _repo.SaveAll()) { return(NoContent()); } return(BadRequest("Could not set photo to main")); }