public async Task <ActionResult <Cart> > PostCart(CartPostModel NewItem) { //Kiem tra hop le if (!ModelState.IsValid) { return(Ok(new { error_message = "Loi gio hang" })); } //Kiem tra sach co ton tai Book book = await _bookServices.GetBookById(NewItem.BookId); if (book is null) { return(Ok(new { error_message = "Sach khong ton tai" })); } //Kiem tra so luong if (book.Quantity <= 0) { return(Ok(new { error_message = "Sach da het so luong" })); } //Kiem tra so luong ton if (book.Quantity - NewItem.Amount <= 0) { return(Ok(new { error_message = "So luong sach con lai trong kho chi con " + NewItem.Amount })); } Cart CurrentCart = await _cartServices.FindAsync(NewItem); if (CurrentCart is not null) { if (NewItem.Amount <= 0) { List <Cart> carts = await _cartServices.DeleteCartById(CurrentCart); return(Ok(new { data = carts, success = true })); } //Cap nhat lai gio hang CurrentCart.Amount += NewItem.Amount; CurrentCart.SubTotal = CurrentCart.Amount * book.Price; if (await _cartServices.UpdateAsync(CurrentCart)) { return(Ok(new { data = await _cartServices.GetCartFromUser(NewItem.UserId), success = true })); } else { return(Ok(new { error_message = "Co loi khi cap nhat gio hang" })); } } else { if (NewItem.Amount <= 0) { return(Ok(new { error_message = "So luong sach khong hop le" })); } Cart cart = new Cart { UserId = NewItem.UserId, BookId = NewItem.BookId, Amount = NewItem.Amount, SubTotal = NewItem.Amount * book.Price }; if (await _cartServices.AddNewCartAsync(cart)) { return(Ok(new { data = await _cartServices.GetCartFromUser(NewItem.UserId), success = true })); } else { return(Ok(new { error_message = "Loi them gio hang" })); } } //return CreatedAtAction("GetCart", new { id = cart.Id }, cart); }