/// <inheritdoc />
public HdAddress GetOrCreateChangeAddress(HdAccount account)
{
// get address to send the change to
var changeAddress = account.GetFirstUnusedChangeAddress();
// no more change addresses left. create a new one.
if (changeAddress == null)
{
var accountAddress = account.CreateAddresses(this.network, 1, isChange: true).Single();
changeAddress = account.InternalAddresses.First(a => a.Address == accountAddress);
// persists the address to the wallet file
this.SaveToFile();
// adds the address to the list of tracked addresses
this.LoadKeysLookup();
}
return(changeAddress);
}
/// <inheritdoc />
public (string hex, uint256 transactionId, Money fee) BuildTransaction(WalletAccountReference accountReference, string password, Script destinationScript, Money amount, FeeType feeType, int minConfirmations)
{
if (amount == Money.Zero)
{
throw new WalletException($"Cannot send transaction with 0 {this.coinType}");
}
// get the wallet and the account
Wallet wallet = this.GetWalletByName(accountReference.WalletName);
HdAccount account = this.GetAccounts(wallet).GetAccountByName(accountReference.AccountName);
// get a list of transactions outputs that have not been spent
var spendableTransactions = account.GetSpendableTransactions().ToList();
// remove whats under min confirmations
var currentHeight = this.chain.Height;
spendableTransactions = spendableTransactions.Where(s => currentHeight - s.BlockHeight >= minConfirmations).ToList();
// get total spendable balance in the account.
var balance = spendableTransactions.Sum(t => t.Amount);
// make sure we have enough funds
if (balance < amount)
{
throw new WalletException("Not enough funds.");
}
// calculate which addresses needs to be used as well as the fee to be charged
var calculationResult = this.CalculateFees(spendableTransactions, amount, feeType.ToConfirmations());
// get extended private key
var privateKey = Key.Parse(wallet.EncryptedSeed, password, wallet.Network);
var seedExtKey = new ExtKey(privateKey, wallet.ChainCode);
var signingKeys = new HashSet <ISecret>();
var coins = new List <Coin>();
foreach (var transactionToUse in calculationResult.transactionsToUse)
{
var address = account.FindAddressesForTransaction(t => t.Id == transactionToUse.Id && t.Index == transactionToUse.Index && t.Amount > 0).Single();
ExtKey addressExtKey = seedExtKey.Derive(new KeyPath(address.HdPath));
BitcoinExtKey addressPrivateKey = addressExtKey.GetWif(wallet.Network);
signingKeys.Add(addressPrivateKey);
coins.Add(new Coin(transactionToUse.Id, (uint)transactionToUse.Index, transactionToUse.Amount, transactionToUse.ScriptPubKey));
}
// get address to send the change to
var changeAddress = account.GetFirstUnusedChangeAddress();
// build transaction
var builder = new TransactionBuilder();
Transaction tx = builder
.AddCoins(coins)
.AddKeys(signingKeys.ToArray())
.Send(destinationScript, amount)
.SetChange(changeAddress.ScriptPubKey)
.SendFees(calculationResult.fee)
.BuildTransaction(true);
if (!builder.Verify(tx))
{
throw new WalletException("Could not build transaction, please make sure you entered the correct data.");
}
return(tx.ToHex(), tx.GetHash(), calculationResult.fee);
}