public async Task <IActionResult> CreateOnChainTransaction(string storeId, string cryptoCode,
[FromBody] CreateOnChainTransactionRequest request)
{
if (IsInvalidWalletRequest(cryptoCode, out var network,
out var derivationScheme, out var actionResult))
{
return(actionResult);
}
if (network.ReadonlyWallet)
{
return(this.CreateAPIError(503, "not-available",
$"{cryptoCode} sending services are not currently available"));
}
//This API is only meant for hot wallet usage for now. We can expand later when we allow PSBT manipulation.
if (!(await CanUseHotWallet()).HotWallet)
{
return(this.CreateAPIError(503, "not-available", $"You need to allow non-admins to use hotwallets for their stores (in /server/policies)"));
}
if (request.Destinations == null || !request.Destinations.Any())
{
ModelState.AddModelError(
nameof(request.Destinations),
"At least one destination must be specified"
);
return(this.CreateValidationError(ModelState));
}
if (request.SelectedInputs != null && request.ExcludeUnconfirmed == true)
{
ModelState.AddModelError(
nameof(request.ExcludeUnconfirmed),
"Can't automatically exclude unconfirmed UTXOs while selection custom inputs"
);
return(this.CreateValidationError(ModelState));
}
var explorerClient = _explorerClientProvider.GetExplorerClient(cryptoCode);
var wallet = _btcPayWalletProvider.GetWallet(network);
var utxos = await wallet.GetUnspentCoins(derivationScheme.AccountDerivation, request.ExcludeUnconfirmed);
if (request.SelectedInputs != null || !utxos.Any())
{
utxos = utxos.Where(coin => request.SelectedInputs?.Contains(coin.OutPoint) ?? true)
.ToArray();
if (utxos.Any() is false)
{
//no valid utxos selected
request.AddModelError(transactionRequest => transactionRequest.SelectedInputs,
"There are no available utxos based on your request", this);
}
}
var balanceAvailable = utxos.Sum(coin => coin.Value.GetValue(network));
var subtractFeesOutputsCount = new List <int>();
var subtractFees = request.Destinations.Any(o => o.SubtractFromAmount);
int?payjoinOutputIndex = null;
var sum = 0m;
var outputs = new List <WalletSendModel.TransactionOutput>();
for (var index = 0; index < request.Destinations.Count; index++)
{
var destination = request.Destinations[index];
if (destination.SubtractFromAmount)
{
subtractFeesOutputsCount.Add(index);
}
BitcoinUrlBuilder?bip21 = null;
var amount = destination.Amount;
if (amount.GetValueOrDefault(0) <= 0)
{
amount = null;
}
var address = string.Empty;
try
{
bip21 = new BitcoinUrlBuilder(destination.Destination, network.NBitcoinNetwork);
amount ??= bip21.Amount.GetValue(network);
if (bip21.Address is null)
{
request.AddModelError(transactionRequest => transactionRequest.Destinations[index],
"This BIP21 destination is missing a bitcoin address", this);
}
else
{
address = bip21.Address.ToString();
}
if (destination.SubtractFromAmount)
{
request.AddModelError(transactionRequest => transactionRequest.Destinations[index],
"You cannot use a BIP21 destination along with SubtractFromAmount", this);
}
}
catch (FormatException)
{
try
{
address = BitcoinAddress.Create(destination.Destination, network.NBitcoinNetwork).ToString();
}
catch (Exception)
{
request.AddModelError(transactionRequest => transactionRequest.Destinations[index],
"Destination must be a BIP21 payment link or an address", this);
}
}
if (amount is null || amount <= 0)
{
request.AddModelError(transactionRequest => transactionRequest.Destinations[index],
"Amount must be specified or destination must be a BIP21 payment link, and greater than 0", this);
}
if (request.ProceedWithPayjoin && bip21?.UnknownParameters?.ContainsKey(PayjoinClient.BIP21EndpointKey) is true)
{
payjoinOutputIndex = index;
}
outputs.Add(new WalletSendModel.TransactionOutput()
{
DestinationAddress = address,
Amount = amount,
SubtractFeesFromOutput = destination.SubtractFromAmount
});
sum += destination.Amount ?? 0;
}
if (subtractFeesOutputsCount.Count > 1)
{
foreach (var subtractFeesOutput in subtractFeesOutputsCount)
{
request.AddModelError(model => model.Destinations[subtractFeesOutput].SubtractFromAmount,
"You can only subtract fees from one destination", this);
}
}
if (balanceAvailable < sum)
{
request.AddModelError(transactionRequest => transactionRequest.Destinations,
"You are attempting to send more than is available", this);
}
else if (balanceAvailable == sum && !subtractFees)
{
request.AddModelError(transactionRequest => transactionRequest.Destinations,
"You are sending your entire balance, you should subtract the fees from a destination", this);
}
var minRelayFee = _nbXplorerDashboard.Get(network.CryptoCode).Status.BitcoinStatus?.MinRelayTxFee ??
new FeeRate(1.0m);
if (request.FeeRate != null && request.FeeRate < minRelayFee)
{
ModelState.AddModelError(nameof(request.FeeRate),
"The fee rate specified is lower than the current minimum relay fee");
}
if (!ModelState.IsValid)
{
return(this.CreateValidationError(ModelState));
}
CreatePSBTResponse psbt;
try
{
psbt = await _walletsController.CreatePSBT(network, derivationScheme,
new WalletSendModel()
{
SelectedInputs = request.SelectedInputs?.Select(point => point.ToString()),
Outputs = outputs,
AlwaysIncludeNonWitnessUTXO = true,
InputSelection = request.SelectedInputs?.Any() is true,
AllowFeeBump =
!request.RBF.HasValue ? WalletSendModel.ThreeStateBool.Maybe :
request.RBF.Value ? WalletSendModel.ThreeStateBool.Yes :
WalletSendModel.ThreeStateBool.No,
FeeSatoshiPerByte = request.FeeRate?.SatoshiPerByte,
NoChange = request.NoChange
},
CancellationToken.None);
}