/// <exception cref="ArgumentException"></exception>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="ArgumentOutOfRangeException"></exception>
public BuildTransactionResult BuildTransaction(
PaymentIntent payments,
Func <FeeRate> feeRateFetcher,
IEnumerable <OutPoint> allowedInputs = null,
Func <LockTime> lockTimeSelector = null,
IPayjoinClient payjoinClient = null)
{
payments = Guard.NotNull(nameof(payments), payments);
lockTimeSelector ??= () => LockTime.Zero;
long totalAmount = payments.TotalAmount.Satoshi;
if (totalAmount < 0 || totalAmount > Constants.MaximumNumberOfSatoshis)
{
throw new ArgumentOutOfRangeException($"{nameof(payments)}.{nameof(payments.TotalAmount)} sum cannot be smaller than 0 or greater than {Constants.MaximumNumberOfSatoshis}.");
}
// Get allowed coins to spend.
var availableCoinsView = Coins.Available();
List <SmartCoin> allowedSmartCoinInputs = AllowUnconfirmed // Inputs that can be used to build the transaction.
? availableCoinsView.ToList()
: availableCoinsView.Confirmed().ToList();
if (allowedInputs is { }) // If allowedInputs are specified then select the coins from them.
private PSBT TryNegotiatePayjoin(IPayjoinClient payjoinClient, TransactionBuilder builder, PSBT psbt, HdPubKey changeHdPubKey)
{
try
{
Logger.LogInfo($"Negotiating payjoin payment with `{payjoinClient.PaymentUrl}`.");
psbt = payjoinClient.RequestPayjoin(
psbt,
KeyManager.ExtPubKey,
new RootedKeyPath(KeyManager.MasterFingerprint.Value, KeyManager.AccountKeyPath),
changeHdPubKey,
CancellationToken.None).GetAwaiter().GetResult(); // WTF??!
builder.SignPSBT(psbt);
Logger.LogInfo($"Payjoin payment was negotiated successfully.");
}
catch (HttpRequestException ex) when(ex.InnerException is TorConnectCommandFailedException innerEx)
{
if (innerEx.Message.Contains("HostUnreachable"))
{
Logger.LogWarning($"Payjoin server is not reachable. Ignoring...");
}
// Ignore.
}
catch (HttpRequestException e)
{
Logger.LogWarning($"Payjoin server responded with {e.ToTypeMessageString()}. Ignoring...");
}
catch (PayjoinException e)
{
Logger.LogWarning($"Payjoin server responded with {e.Message}. Ignoring...");
}
return(psbt);
}
/// <exception cref="ArgumentException"></exception>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="ArgumentOutOfRangeException"></exception>
public BuildTransactionResult BuildTransaction(
PaymentIntent payments,
FeeRate feeRate,
IEnumerable <OutPoint> allowedInputs = null,
IPayjoinClient payjoinClient = null)
=> BuildTransaction(payments, () => feeRate, allowedInputs, () => LockTime.Zero, payjoinClient);
/// <exception cref="ArgumentException"></exception>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="ArgumentOutOfRangeException"></exception>
public BuildTransactionResult BuildTransaction(
PaymentIntent payments,
Func <FeeRate> feeRateFetcher,
IEnumerable <OutPoint> allowedInputs = null,
Func <LockTime> lockTimeSelector = null,
IPayjoinClient payjoinClient = null)
{
payments = Guard.NotNull(nameof(payments), payments);
lockTimeSelector ??= () => LockTime.Zero;
long totalAmount = payments.TotalAmount.Satoshi;
if (totalAmount < 0 || totalAmount > Constants.MaximumNumberOfSatoshis)
{
throw new ArgumentOutOfRangeException($"{nameof(payments)}.{nameof(payments.TotalAmount)} sum cannot be smaller than 0 or greater than {Constants.MaximumNumberOfSatoshis}.");
}
// Get allowed coins to spend.
var availableCoinsView = Coins.Available();
List <SmartCoin> allowedSmartCoinInputs = AllowUnconfirmed // Inputs that can be used to build the transaction.
? availableCoinsView.ToList()
: availableCoinsView.Confirmed().ToList();
if (allowedInputs != null) // If allowedInputs are specified then select the coins from them.
{
if (!allowedInputs.Any())
{
throw new ArgumentException($"{nameof(allowedInputs)} is not null, but empty.");
}
allowedSmartCoinInputs = allowedSmartCoinInputs
.Where(x => allowedInputs.Any(y => y.Hash == x.TransactionId && y.N == x.Index))
.ToList();
// Add those that have the same script, because common ownership is already exposed.
// But only if the user didn't click the "max" button. In this case he'd send more money than what he'd think.
if (payments.ChangeStrategy != ChangeStrategy.AllRemainingCustom)
{
var allScripts = allowedSmartCoinInputs.Select(x => x.ScriptPubKey).ToHashSet();
foreach (var coin in availableCoinsView.Where(x => !allowedSmartCoinInputs.Any(y => x.TransactionId == y.TransactionId && x.Index == y.Index)))
{
if (!(AllowUnconfirmed || coin.Confirmed))
{
continue;
}
if (allScripts.Contains(coin.ScriptPubKey))
{
allowedSmartCoinInputs.Add(coin);
}
}
}
}
// Get and calculate fee
Logger.LogInfo("Calculating dynamic transaction fee...");
TransactionBuilder builder = Network.CreateTransactionBuilder();
builder.SetCoinSelector(new SmartCoinSelector(allowedSmartCoinInputs));
builder.AddCoins(allowedSmartCoinInputs.Select(c => c.GetCoin()));
builder.SetLockTime(lockTimeSelector());
foreach (var request in payments.Requests.Where(x => x.Amount.Type == MoneyRequestType.Value))
{
var amountRequest = request.Amount;
builder.Send(request.Destination, amountRequest.Amount);
if (amountRequest.SubtractFee)
{
builder.SubtractFees();
}
}
HdPubKey changeHdPubKey = null;
if (payments.TryGetCustomRequest(out DestinationRequest custChange))
{
var changeScript = custChange.Destination.ScriptPubKey;
changeHdPubKey = KeyManager.GetKeyForScriptPubKey(changeScript);
var changeStrategy = payments.ChangeStrategy;
if (changeStrategy == ChangeStrategy.Custom)
{
builder.SetChange(changeScript);
}
else if (changeStrategy == ChangeStrategy.AllRemainingCustom)
{
builder.SendAllRemaining(changeScript);
}
else
{
throw new NotSupportedException(payments.ChangeStrategy.ToString());
}
}
else
{
KeyManager.AssertCleanKeysIndexed(isInternal: true);
KeyManager.AssertLockedInternalKeysIndexed(14);
changeHdPubKey = KeyManager.GetKeys(KeyState.Clean, true).RandomElement();
builder.SetChange(changeHdPubKey.P2wpkhScript);
}
builder.OptInRBF = new Random().NextDouble() < Constants.TransactionRBFSignalRate;
FeeRate feeRate = feeRateFetcher();
builder.SendEstimatedFees(feeRate);
var psbt = builder.BuildPSBT(false);
var spentCoins = psbt.Inputs.Select(txin => allowedSmartCoinInputs.First(y => y.OutPoint == txin.PrevOut)).ToArray();
var realToSend = payments.Requests
.Select(t =>
(label: t.Label,
destination: t.Destination,
amount: psbt.Outputs.FirstOrDefault(o => o.ScriptPubKey == t.Destination.ScriptPubKey)?.Value))
.Where(i => i.amount != null);
if (!psbt.TryGetFee(out var fee))
{
throw new InvalidOperationException("Impossible to get the fees of the PSBT, this should never happen.");
}
Logger.LogInfo($"Fee: {fee.Satoshi} Satoshi.");
var vSize = builder.EstimateSize(psbt.GetOriginalTransaction(), true);
Logger.LogInfo($"Estimated tx size: {vSize} vBytes.");
// Do some checks
Money totalSendAmountNoFee = realToSend.Sum(x => x.amount);
if (totalSendAmountNoFee == Money.Zero)
{
throw new InvalidOperationException("The amount after subtracting the fee is too small to be sent.");
}
Money totalOutgoingAmountNoFee;
if (changeHdPubKey is null)
{
totalOutgoingAmountNoFee = totalSendAmountNoFee;
}
else
{
totalOutgoingAmountNoFee = realToSend.Where(x => !changeHdPubKey.ContainsScript(x.destination.ScriptPubKey)).Sum(x => x.amount);
}
decimal totalOutgoingAmountNoFeeDecimal = totalOutgoingAmountNoFee.ToDecimal(MoneyUnit.BTC);
// Cannot divide by zero, so use the closest number we have to zero.
decimal totalOutgoingAmountNoFeeDecimalDivisor = totalOutgoingAmountNoFeeDecimal == 0 ? decimal.MinValue : totalOutgoingAmountNoFeeDecimal;
decimal feePc = 100 * fee.ToDecimal(MoneyUnit.BTC) / totalOutgoingAmountNoFeeDecimalDivisor;
if (feePc > 1)
{
Logger.LogInfo($"The transaction fee is {feePc:0.#}% of the sent amount.{Environment.NewLine}"
+ $"Sending:\t {totalOutgoingAmountNoFee.ToString(fplus: false, trimExcessZero: true)} BTC.{Environment.NewLine}"
+ $"Fee:\t\t {fee.Satoshi} Satoshi.");
}
if (feePc > 100)
{
throw new InvalidOperationException($"The transaction fee is more than twice the sent amount: {feePc:0.#}%.");
}
if (spentCoins.Any(u => !u.Confirmed))
{
Logger.LogInfo("Unconfirmed transaction is spent.");
}
// Build the transaction
Logger.LogInfo("Signing transaction...");
// It must be watch only, too, because if we have the key and also hardware wallet, we do not care we can sign.
Transaction tx = null;
if (KeyManager.IsWatchOnly)
{
tx = psbt.GetGlobalTransaction();
}
else
{
IEnumerable <ExtKey> signingKeys = KeyManager.GetSecrets(Password, spentCoins.Select(x => x.ScriptPubKey).ToArray());
builder = builder.AddKeys(signingKeys.ToArray());
builder.SignPSBT(psbt);
UpdatePSBTInfo(psbt, spentCoins, changeHdPubKey);
if (!KeyManager.IsWatchOnly)
{
// Try to pay using payjoin
if (payjoinClient is { })
