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const axios = require("axios");
const liquid = require("liquidjs-lib");
const coinselect = require("coinselect");
const split = require("coinselect/split");
const api = prod ? "https://blockstream.info/liquid/api" : "http://localhost:3002";
const SATS = 100000000;
const network = prod ? liquid.networks["liquid"] : liquid.networks["regtest"];
module.exports = async ({ address, asset, amount, feeRate, user }) => {
const { btcasset: btc } = config.liquid;
if (!feeRate) {
let { feerate } = await lq.estimateSmartFee(6);
if (!feerate) feerate = 0.00002;
feeRate = feerate * SATS;
}
feeRate = Math.round(feeRate / 100);
if (asset !== btc) feeRate = 0;
const payments = await db.Payment.findAll({
where: {
received: true,
account_id: user.account_id,
},
});
let utxos = [];
for (let i = 0; i < payments.length; i++) {
let url = `${api}/address/${payments[i].address}/utxo`;
try {
utxos.push(...(await axios.get(url)).data);
} catch (e) {
l.error("problem fetching utxos", e.message, url);
}
}
let feeInput = utxos.find((utxo) => utxo.asset === btc && utxo.value > 1000);
if (!feeInput) throw new Error("Couldn't find fee input");
utxos = utxos.filter((utxo) => utxo.asset === asset);
let feeChange = feeInput.value - 1000;
let targets = [
{
address,
value: amount,
},
];
let { inputs, outputs, fee } = coinselect(utxos, targets, feeRate);
if (!inputs || !outputs) {
l.info(
"utxos",
amount,
feeRate,
utxos.map((u) => u.value),
inputs,
outputs,
fee
);
throw new Error(
"Couldn't find inputs for transaction, check your balance/fee"
);
}
let psbt = new liquid.Psbt({ network });
let total = 0;
let { address: changeAddress } = payments[payments.length - 1];
outputs.map(({ address, value }) => {
total += value;
if (!address) {
address = changeAddress;
change.push(address);
}
psbt = psbt.addOutput({
address,
asset,
value,
});
});
for (let i = 0; i < inputs.length; i++) {
let { txid, vout } = inputs[i];
psbt = psbt.addInput({
hash: txid,
index: vout,
nonWitnessUtxo: Buffer.from((await lq.getTransaction(txid)).hex, "hex"),
});
}
if (asset !== btc) {
psbt.addInput({
hash: feeInput.txid,
index: feeInput.vout,
nonWitnessUtxo: Buffer.from(
(await lq.getTransaction(feeInput.txid).hex),
"hex"
),
});
psbt.addOutput({
changeAddress,
asset: btc,
value: feeChange,
});
}
psbt.addOutput({
asset: btc,
script: Buffer.alloc(0),
value: fee,
nonce: Buffer.alloc(1, 0),
});
feeRate = Math.round(feeRate * 1000);
psbt = psbt.toBase64();
return { tx: psbt, feeRate };
};
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