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const axios = require("axios");
const bitcoin = require("bitcoinjs-lib");
const coinselect = require("coinselect");
const split = require("coinselect/split");
const api = prod ? "https://blockstream.info/api" : "http://localhost:3002";
const SATS = 100000000;
const network = prod
? bitcoin.networks["bitcoin"]
: bitcoin.networks["regtest"];
module.exports = ah(async (req, res) => {
let { address: from, amount, feeRate, target } = req.body;
let utxos;
if (!feeRate) feeRate = (await bc.estimateSmartFee(6)).feerate * SATS;
feeRate = Math.round(feeRate / 1000);
l.info("sweeping", req.user.username, from, amount, feeRate);
let {
data: {
chain_stats: { funded_txo_sum: funded, spent_txo_sum: spent }
}
} = await axios.get(`${api}/address/${from}`);
let balance = funded - spent;
try {
({ data: utxos } = await axios.get(`${api}/address/${from}/utxo`));
} catch (e) {
l.error("problem fetching utxos", e.message);
}
let targets = [
{
address: target,
value: amount
}
];
let { inputs, outputs, fee } = coinselect(utxos, targets, feeRate);
if (balance === amount) {
delete targets[0].value;
({ inputs, outputs, fee } = split(utxos, targets, feeRate));
l.info("split", inputs, outputs, fee);
}
if (!inputs || !outputs)
return res
.status(500)
.send("Unable to construct sweep transaction, try a lower fee rate?");
let psbt = new bitcoin.Psbt({ network });
let total = 0;
outputs.map(({ address, value }) => {
total += value;
psbt = psbt.addOutput({
address: address || from,
value
});
});
for (let i = 0; i < inputs.length; i++) {
let { txid, vout } = inputs[i];
let nonWitnessUtxo = Buffer.from(await bc.getRawTransaction(txid), "hex");
psbt = psbt.addInput({
hash: txid,
index: vout,
nonWitnessUtxo
});
}
feeRate = Math.round(feeRate * 1000);
psbt = psbt.toBase64();
if (balance !== amount) total = 0;
res.send({ feeRate, psbt, total });
});
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