scrypt test 2

const axios = require('axios');
const bsv = require('bsv');
var fs = require('fs');
var path = require('path');
let BN = bsv.crypto.BN

__dirname = path.resolve();
function int2SM(num) {
    let n = BN.fromNumber(num)
    let m = n.toSM({ endian: 'little'} )
    return m.toString('hex')
}

(async() => {

const NETWORK = 'test'
const API_PREFIX = 'https://api.whatsonchain.com/v1/bsv/' + NETWORK
const MIN_FEE = 546
const LOCK_AMOUNT = 100000
const UNLOCK_AMOUNT = LOCK_AMOUNT - 10000
const FLAGS = bsv.Script.Interpreter.SCRIPT_VERIFY_MINIMALDATA | bsv.Script.Interpreter.SCRIPT_ENABLE_SIGHASH_FORKID | bsv.Script.Interpreter.SCRIPT_ENABLE_MAGNETIC_OPCODES | bsv.Script.Interpreter.SCRIPT_ENABLE_MONOLITH_OPCODES
const SIGHASH_TYPE = bsv.crypto.Signature.SIGHASH_ALL | bsv.crypto.Signature.SIGHASH_FORKID

// mainnet
// const key = "L1HBjGiu9W5tsu7axNKRY1cz4xdLuwEnAC7u3b6n2Ex98nNh6UvK"
// testnet
const key = 'cU2eUM62Hkur8sQVv7z1VtkXHHTA1YSGqxjAGYgbDPQaYcg5NXKd'
// const key = 'cPkteUUh4eG1mjkhphV1MZWm7JmYZuK4j8LaDpPwo3mxcZW49ibj'
// const key = 'cTzbQjXykayjM7rkERDeyf9h6V9DjsHqv7twhtU78EkqksQ95LJD'
const privateKey = new bsv.PrivateKey(key);
const ADDR = privateKey.toAddress();
// console.log(address.toString()) //'mpRPo9bMQ1HaZetSL7EfaDuzfdLyJ3PVoy' 'mg1Rwf7NTTbgRUYAFiqJk1ryaKx74Y7zDf' 'myfKHweiqRe4z1KRXBEkud3FteCQn23wEr'
const scriptP2PKH = bsv.Script.buildPublicKeyHashOut(ADDR).toHex();
// console.log(script) // 76a91461abec89cd14603c8c7d45f679e93ac0beea866288ac

const fetchUtxos = async (address) => {
    let { data: utxos } = await axios.get(`${API_PREFIX}/address/${ADDR}/unspent`)
    utxos = utxos.map(utxo => ({
        txId: utxo.tx_hash,
        outputIndex: utxo.tx_pos,
        satoshis: utxo.value,
        script: scriptP2PKH
    }))
    return utxos
}

// lock fund in a script
const buildScriptLockTx = (utxos, scriptPubKey) => {
    let tx = new bsv.Transaction().from(utxos)
    tx.addOutput(new bsv.Transaction.Output({
        script: scriptPubKey,
        satoshis: LOCK_AMOUNT
    }))
    tx.addOutput(new bsv.Transaction.Output({
        script: new bsv.Script().add(bsv.Opcode.OP_FALSE).add(bsv.Script.buildDataOut(['sCrypt: the UTXO above (vout[0]) cannot be spent before CoinGeek London 2020'])),
        satoshis: 546
    }))
    tx.change(ADDR)
    if (tx.getFee() < MIN_FEE) {
        tx.fee(MIN_FEE)
    }
    return tx.sign(privateKey)
}

// unlock fund from a script
const buildScriptUnlockTx = (prevTxId, scriptPubKey) => {
    tx = new bsv.Transaction().addInput(new bsv.Transaction.Input({
        prevTxId: prevTxId,
        outputIndex: 0,
        script: new bsv.Script(),   // placeholder
    }), scriptPubKey, LOCK_AMOUNT)
    tx.addOutput(new bsv.Transaction.Output({
        script: scriptPubKey,
        satoshis: UNLOCK_AMOUNT
    }))
    tx.nLockTime = 1582156800
    // no need to sign since scriptSig is already set
    return tx
}

const sendTx = async (txhex) => {
    const { data: txid } = await axios.post(`${API_PREFIX}/tx/raw`, {
        txhex: txhex
    })
    return txid
}

try {
    const scriptPubKeyStr = fs.readFileSync(path.join(__dirname, 'cltv_asm.json'), { encoding: 'utf8' })
    const scriptPubKey = bsv.Script.fromASM(scriptPubKeyStr)

    // step 1: fetch utxos
    const utxos = await fetchUtxos(ADDR)
    // console.log('utxos: ', utxos)

    // step 2: build the locking tx and sign it
    const lockingTx = buildScriptLockTx(utxos, scriptPubKey)

    // step 3: serialize and broadcast the locking tx
    const lockingTxid = await sendTx(lockingTx.serialize())
    console.log('locking tx id:     ', lockingTxid)

    // step 4: build the unlocking tx
    const unlockingTx = await buildScriptUnlockTx(lockingTxid, scriptPubKey)
    const INPUT_IDX = 0
    const preimage = bsv.Transaction.sighash.sighashPreimage(unlockingTx, SIGHASH_TYPE, INPUT_IDX, scriptPubKey, new bsv.crypto.BN(LOCK_AMOUNT), FLAGS)
    const preimageASM = preimage.toString('hex')
    const scriptSigStr = preimageASM
    const scriptSig = bsv.Script.fromASM(scriptSigStr)
    unlockingTx.inputs[INPUT_IDX].setScript(scriptSig)

    // step 5: serialized and send it
    const unlockingTxid = await sendTx(unlockingTx.serialize())
    console.log('unlocking tx id:   ', unlockingTxid)

} catch (error) {
    // Error
    if (error.response) {
        // The request was made and the server responded with a status code
        // that falls out of the range of 2xx
        console.log('Failed - StatusCodeError: ' + error.response.status + ' - "' + error.response.data + '"')
        // console.log(error.response.headers);
    } else if (error.request) {
        // The request was made but no response was received
        // `error.request` is an instance of XMLHttpRequest in the
        // browser and an instance of
        // http.ClientRequest in node.js
        console.log(error.request);
    } else {
        // Something happened in setting up the request that triggered an Error
        console.log('Error', error.message);
    }
    console.log(error.config);
}


})()