Signet.kt

package ru.disav.signet

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material3.Scaffold
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.ui.tooling.preview.Preview
import org.bitcoinj.base.Address
import org.bitcoinj.base.AddressParser
import org.bitcoinj.base.BitcoinNetwork
import org.bitcoinj.base.Coin
import org.bitcoinj.base.Sha256Hash
import org.bitcoinj.core.Context
import org.bitcoinj.core.Transaction
import org.bitcoinj.core.TransactionConfidence
import org.bitcoinj.core.TransactionOutPoint
import org.bitcoinj.core.UTXO
import org.bitcoinj.crypto.DumpedPrivateKey
import org.bitcoinj.crypto.ECKey
import org.bitcoinj.script.ScriptBuilder
import org.bouncycastle.util.encoders.Hex
import ru.disav.signet.ui.theme.SignetTheme

/**
 *   {
 *     "txid": "7365cc68f64ba5d2b092d2b9a452ba2473641f5fbc2ed35f1726ec2672513718",
 *     "vout": 0,
 *     "status": {
 *       "confirmed": true,
 *       "block_height": 213060,
 *       "block_hash": "0000004df88f08f785ede857dd02e3941abecf82309a5eae5a04a57b9c7b3189",
 *       "block_time": 1726232391
 *     },
 *     "value": 10000
 *   },
 *     {
 *     "txid": "44e95d4e29eb1917ff393c624883b2003c7517334898ccb43e65a6887f288271",
 *     "vout": 0,
 *     "status": {
 *       "confirmed": true,
 *       "block_height": 213060,
 *       "block_hash": "0000004df88f08f785ede857dd02e3941abecf82309a5eae5a04a57b9c7b3189",
 *       "block_time": 1726232391
 *     },
 *     "value": 852
 *   }
 */

object TransactionFactory {
    fun create(
        sendAmount: Coin,
        changeAmount: Coin,
        ecKey: ECKey,
        addressReceiver: Address,
        addressChange: Address,
        utxos: List<UTXO>
    ): Transaction {
        val transaction = Transaction()
        transaction.addOutput(sendAmount, addressReceiver)
        transaction.addOutput(changeAmount, addressChange)

        for (utxoItem in utxos) {
            val outPoint = TransactionOutPoint(utxoItem.index, utxoItem.hash)
            transaction.addSignedInput(
                /* prevOut = */ outPoint,
                /* scriptPubKey = */ ScriptBuilder.createOutputScript(addressChange),
                /* amount = */ utxoItem.value,
                /* sigKey = */ ecKey,
            )
        }

        transaction.purpose = Transaction.Purpose.USER_PAYMENT

        return transaction
    }
}

interface UTXOSource {
    fun load(address: Address): List<UTXO>
}

class DummyUTXOSource : UTXOSource {
    override fun load(address: Address) = listOf(
        UTXO(
            /* hash = */ Sha256Hash.wrap("44e95d4e29eb1917ff393c624883b2003c7517334898ccb43e65a6887f288271"),
            /* index = */ 0,
            /* value = */ Coin.valueOf(852),
            /* height = */ 213060,
            /* coinbase = */ false,
            /* script = */ ScriptBuilder.createOutputScript(address)
        ),
        UTXO(
            /* hash = */ Sha256Hash.wrap("7365cc68f64ba5d2b092d2b9a452ba2473641f5fbc2ed35f1726ec2672513718"),
            /* index = */ 1,
            /* value = */ Coin.valueOf(10000),
            /* height = */ 213060,
            /* coinbase = */ false,
            /* script = */ ScriptBuilder.createOutputScript(address)
        )
    )
}
// curl -X POST -sSLd "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" "https://mempool.space/api/tx"

private const val MINER_FEE = 1000L
private const val RECEIVER_ADDRESS = "tb1qzt6j7slr5h0c8cnmdpu0n2d9yq0am3y69rfu6j"
private const val CHANGE_ADDRESS = "tb1qsdq8xnnkpvrjwwdh8870ueunff7ds8g63y8ep5"
private const val PRIVATE_KEY = "cRfMHmheNWpA9L5dn9SvUbWgzEydiLxz6hDQbboAx2AyaJ5ASpY6"

fun main() {
    val addressReceiver = AddressParser
        .getDefault(BitcoinNetwork.SIGNET)
        .parseAddress(RECEIVER_ADDRESS)

    val addressChange = AddressParser
        .getDefault(BitcoinNetwork.SIGNET)
        .parseAddress(CHANGE_ADDRESS)

    val utxos = DummyUTXOSource().load(addressChange)

    val totalAmount = utxos.sumOf { it.value.value }
    val amountToSend = Coin.valueOf(1000)
    val minerFee = Coin.valueOf(MINER_FEE)
    val change = Coin
        .valueOf(totalAmount)
        .minus(amountToSend)
        .minus(minerFee)

    val ecKey = DumpedPrivateKey
        .fromBase58(BitcoinNetwork.SIGNET, PRIVATE_KEY)
        .key

    val transaction = TransactionFactory.create(amountToSend, change, ecKey, addressReceiver, addressChange, utxos)

    Context.getOrCreate()
    transaction.confidence.setSource(TransactionConfidence.Source.SELF);

    println(transaction)
    println(Hex.toHexString(transaction.bitcoinSerialize()))
}