Tích hợp thanh toán VnPayment AspNet Core

"Payment": {
    "VnPayment": {
        "Version": "2.1.0",
        "Command": "pay",
        "TmnCode": "HBTTB7MH",
        "HashSecret": "3OU76PCUYSQUJ7IUSS2B8STHPABH5C9S",
        "CurrCode": "VND",
        "Locale": "vn",
        "OrderType": "other",
        "ReturnUrl": "http://localhost:5090/cart/vnpaymentResponse",
        "BaseUrl": "https://sandbox.vnpayment.vn/paymentv2/vpcpay.html"
    }
}

public class VnPayment{
    public string Version { get; set; } = null!;
    public string Command { get; set; } = null!;
    public string TmnCode { get; set; } = null!;
    public string HashSecret { get; set; } = null!;
    public string CurrCode { get; set; } = null!;
    public string Locale { get; set; } = null!;
    public string OrderType { get; set; } = null!;
    public string ReturnUrl { get; set; } = null!;
    public decimal Amount { get; set; }
    public DateTime CreateDate { get; set; }
    public string IpAddr { get; set; } = null!;
    public string OrderInfo { get; set; } = null!;
    public string TxnRef { get; set; } = null!;
    public string SecureHash { get; set; } = null!;
    public string BaseUrl { get; set; } = null!;
}

public class VnPaymentService{
    VnPayment payment;
    IHttpContextAccessor accessor;
    public VnPaymentService(IOptions<VnPayment> options, IHttpContextAccessor accessor){
        payment = options.Value;
        this.accessor = accessor;
    }
    public string ToUrl(Invoice obj){
        SortedDictionary<string, string> dict = new SortedDictionary<string, string>{
            {"vnp_Amount", (obj.Amount * 100).ToString()},
            {"vnp_Command", payment.Command},
            {"vnp_CreateDate", obj.CreateDate.ToString("yyyyMMddHHmmss")},
            {"vnp_CurrCode", payment.CurrCode},
            //{"vnp_IpAddr", "127.0.0.1"},
            {"vnp_IpAddr", accessor.HttpContext!.Connection.RemoteIpAddress!.ToString()},
            {"vnp_Locale", payment.Locale},
            {"vnp_OrderInfo", $"Payment for {obj.InvoiceId} with amount {obj.Amount.ToString()}"},
            {"vnp_OrderType", payment.OrderType},
            {"vnp_ReturnUrl", payment.ReturnUrl},
            {"vnp_TmnCode", payment.TmnCode},
            {"vnp_TxnRef", obj.InvoiceId},
            {"vnp_Version", payment.Version},
        };
        string query = string.Join("&", dict.Select(p => $"{p.Key}={WebUtility.UrlEncode(p.Value)}"));
        string secureHash = Helper.HmacSha512(query, payment.HashSecret);
        return $"{payment.BaseUrl}?{query}&vnp_SecureHash={secureHash}";
    }
}

public class Invoice{
    public string InvoiceId { get; set; } = null!;
    public decimal Amount { get; set; }
    public DateTime CreateDate { get; set; }
}
    

[HttpPost]
public IActionResult Checkout(Invoice obj){
    obj.CreateDate = DateTime.Now;
    obj.InvoiceId = Guid.NewGuid().ToString().Replace("-", "");
    string url = vnPayment.ToUrl(obj);
    return Redirect(url);
}
public IActionResult VnPaymentResponse(VnPaymentResponse obj){
    
    return View();
}

public class VnPaymentResponse{
    [BindProperty(Name = "vnp_Amount")] 
    public int Amount { get; set; }
    [BindProperty( Name = "vnp_BankCode")]
    public string BankCode { get; set; } = null!;
    [BindProperty(Name = "vnp_BankTranNo")]
    public string BankTranNo { get; set; } = null!;
    [BindProperty(Name = "vnp_CardType")]
    public string CardType { get; set; } = null!;
    [BindProperty(Name = "vnp_OrderInfo")]
    public string OrderInfo { get; set; } = null!;
    [BindProperty(Name = "vnp_PayDate")]
    public string PayDate { get; set; } = null!;
    [BindProperty(Name = "vnp_ResponseCode")]
    public string ResponseCode { get; set; } = null!;
    [BindProperty(Name = "vnp_TmnCode")]
    public string TmnCode { get; set; } = null!;
    [BindProperty(Name = "vnp_TransactionNo")]
    public string TransactionNo { get; set; } = null!;
    [BindProperty(Name = "vnp_TransactionStatus")]
    public string TransactionStatus { get; set; } = null!;
    [BindProperty(Name = "vnp_TxnRef")]
    public string TxnRef { get; set; } = null!;
    [BindProperty(Name = "vnp_SecureHash")]
    public string SecureHash { get; set; } = null!;
}