/// <summary>
/// Signs the given transaction with the given private key.
/// The result signature will be assigned to all inputs of the transaction.
/// </summary>
private static void signTransation(Transaction tx, EllipticCurve.PrivateKey privateKey)
{
var sig = EllipticCurve.Ecdsa.sign(tx.Id, privateKey);
var sigStr = AddressUtils.TxInSignatureFromSignatureAndPublicKey(sig, privateKey.publicKey());
for (int i = 0, c = tx.Inputs.Count; i < c; ++i)
{
tx.Inputs[i].Signature = sigStr;
}
}
/// <summary>
/// Creates a transaction for sending coins from the given wallet to the given address.
/// </summary>
/// <param name="senderAddress">Address of the sender wallet.</param>
/// <param name="recipientAddress">Address of the recipient wallet.</param>
/// <param name="amountInNekoshi">Amount of nekoshi to send, not including transaction fee.</param>
/// <param name="privateKey">Private key of the sender wallet.</param>
/// <returns>Result of the task.</returns>
/// <remarks>
/// If the task succeeds, a pending transaction will be added to the mempool.
/// The application is responsible for broadcasting the pending transaction
/// to other nodes.
/// </remarks>
public SendResult Send(string senderAddress, string recipientAddress, long amountInNekoshi, EllipticCurve.PrivateKey privateKey)
{
var addrFromPrivateKey = AddressUtils.AddressFromPrivateKey(privateKey);
if (senderAddress != addrFromPrivateKey)
{
return new SendResult {
Error = SendResult.ErrorType.InvalidKey
}
}
;
long amountInNekoshiToSend = amountInNekoshi;
amountInNekoshi += Config.FeeNekoshiPerTx;
List <UnspentTxOut> unspentTxOutputs = new List <UnspentTxOut>();
List <TxOut> pendingTxOutputs = new List <TxOut>();
getUnspentTxOutputs(senderAddress, unspentTxOutputs, pendingTxOutputs);
long accumulatedAmount = 0;
List <UnspentTxOut> ouputsToSpend = new List <UnspentTxOut>();
List <TxOut> changeOutputs = new List <TxOut>();
for (int i = 0, c = unspentTxOutputs.Count; i < c; ++i)
{
var utxo = unspentTxOutputs[i];
ouputsToSpend.Add(utxo);
var refTx = transactionDb.GetTransaction(utxo.TxId);
var txOut = refTx.Outputs[utxo.TxOutIndex];
long neededAmount = amountInNekoshi - accumulatedAmount;
if (txOut.AmountInNekoshi > neededAmount)
{
accumulatedAmount = amountInNekoshi;
changeOutputs.Add(new TxOut
{
Address = senderAddress,
AmountInNekoshi = txOut.AmountInNekoshi - neededAmount,
});
}
else
{
accumulatedAmount += txOut.AmountInNekoshi;
}
if (accumulatedAmount >= amountInNekoshi)
{
break;
}
}
if (accumulatedAmount >= amountInNekoshi)
{
if (ouputsToSpend.Count > Config.MaxTransactionInputs)
{
return new SendResult {
Error = SendResult.ErrorType.TooManyInputs
}
}
;
var tx = new Transaction();
for (int i = 0, c = ouputsToSpend.Count; i < c; ++i)
{
var unspentTxOut = ouputsToSpend[i];
var txIn = new TxIn
{
TxId = unspentTxOut.TxId,
TxOutIndex = unspentTxOut.TxOutIndex,
};
tx.Inputs.Add(txIn);
}
changeOutputs.Add(new TxOut
{
Address = recipientAddress,
AmountInNekoshi = amountInNekoshiToSend,
});
tx.Outputs.AddRange(changeOutputs);
tx.Id = tx.GetId();
signTransation(tx, privateKey);
transactionDb.AddPendingTransaction(tx);
return(new SendResult
{
Error = SendResult.ErrorType.None,
TxId = tx.Id,
});
}
else
{
return(new SendResult {
Error = SendResult.ErrorType.Insufficient
});
}
}
