sbtc-bridge-lib/src/withdraw_utils.ts

Library for sBTC Bridge web client and API apps

import * as btc from '@scure/btc-signer';
import * as secp from '@noble/secp256k1';
import * as P from 'micro-packed';
import { hex } from '@scure/base';
import type { KeySet, BridgeTransactionType, UTXO, WithdrawPayloadUIType } from './types/sbtc_types.js' 
import { buildWithdrawPayloadOpDrop, toStorable } from './payload_utils.js' 
import { buildWithdrawPayload, amountToBigUint64, bigUint64ToAmount } from './payload_utils.js' 
import { addInputs, getNet, getPegWalletAddressFromPublicKey, inputAmt, toXOnly } from './wallet_utils.js';

const concat = P.concatBytes;

const privKey = hex.decode('0101010101010101010101010101010101010101010101010101010101010101');
export const fullfillmentFee = 2000
export const revealPayment = 10001
export const dust = 500

/**
 * 
 * @param network 
 * @param uiPayload 
 * @param utxos:Array<UTXO>
 * @param btcFeeRates 
 * @returns Transaction from @scure/btc-signer
 */
export function buildWithdrawTransaction(network:string, sbtcWalletPublicKey:string, uiPayload:WithdrawPayloadUIType, utxos:Array<UTXO>, btcFeeRates:any) {
	if (!uiPayload.signature) throw new Error('Signature of output 2 scriptPubKey is required');
	const net = getNet(network);
	const sbtcWalletAddress = getPegWalletAddressFromPublicKey(network, sbtcWalletPublicKey)
	const data = buildData(network, uiPayload.amountSats, uiPayload.signature, false)
	const txFees = calculateWithdrawFees(network, false, utxos, uiPayload.amountSats, btcFeeRates, sbtcWalletAddress!, uiPayload.bitcoinAddress, uiPayload.paymentPublicKey, hex.decode(data))
	const tx = new btc.Transaction({ allowUnknowOutput: true, allowUnknownInputs:true, allowUnknownOutputs:true });
	addInputs(network, uiPayload.amountSats, 0, tx, false, utxos, uiPayload.paymentPublicKey);
	tx.addOutput({ script: btc.Script.encode(['RETURN', hex.decode(data)]), amount: BigInt(0) });
	const change = inputAmt(tx) - (fullfillmentFee + dust + txFees[1]);
	tx.addOutputAddress(uiPayload.bitcoinAddress, BigInt(dust), net);
	tx.addOutputAddress(sbtcWalletAddress!, BigInt(fullfillmentFee), net);
	if (change > 0) tx.addOutputAddress(uiPayload.bitcoinAddress, BigInt(change), net);
	return tx;
}

/**
 * 
 * @param network 
 * @param uiPayload 
 * @param utxos:Array<UTXO>
 * @param btcFeeRates 
 * @param originator 
 * @returns 
 */
export function buildWithdrawTransactionOpDrop (network:string, sbtcWalletPublicKey:string, uiPayload:WithdrawPayloadUIType, utxos:Array<UTXO>, btcFeeRates:any, originator:string) {
	if (!uiPayload.signature) throw new Error('Signature of output 2 scriptPubKey is required');
	const net = getNet(network);
	const sbtcWalletAddress = getPegWalletAddressFromPublicKey(network, sbtcWalletPublicKey)
	const txFees = calculateWithdrawFees(network, true, utxos, uiPayload.amountSats, btcFeeRates, sbtcWalletAddress!, uiPayload.bitcoinAddress, uiPayload.paymentPublicKey, undefined)
	const tx = new btc.Transaction({ allowUnknowOutput: true, allowUnknownInputs:true, allowUnknownOutputs:true });
	addInputs(network, uiPayload.amountSats, revealPayment, tx, false, utxos, uiPayload.paymentPublicKey);
	const csvScript = getBridgeWithdrawOpDrop(network, sbtcWalletPublicKey, uiPayload, originator);
	//(network, data, sbtcWalletAddress, uiPayload.bitcoinAddress);
	if (!csvScript ) throw new Error('script required!');
	
	tx.addOutput({ script: csvScript.commitTxScript!.script, amount: BigInt(0) });
	tx.addOutputAddress(uiPayload.bitcoinAddress, BigInt(dust), net);
	tx.addOutputAddress(sbtcWalletAddress!, BigInt(fullfillmentFee), net);
	const change = inputAmt(tx) - (fullfillmentFee + dust + txFees[1]);
	if (change > 0) tx.addOutputAddress(uiPayload.bitcoinAddress, BigInt(change), net);
	return tx;
}

function calculateWithdrawFees(network:string, opDrop:boolean, utxos:Array<UTXO>, amount:number, feeInfo:{ low_fee_per_kb:number, medium_fee_per_kb:number, high_fee_per_kb:number }, sbtcWalletAddress:string, changeAddress:string, paymentPublicKey:string, data:Uint8Array|undefined) {
	try {
		let vsize = 0;
		const net = getNet(network);
		const tx = new btc.Transaction({ allowUnknowOutput: true, allowUnknownInputs:true, allowUnknownOutputs:true });
		addInputs(network, amount, revealPayment, tx, true, utxos, paymentPublicKey);
		if (!opDrop) {
			if (data) tx.addOutput({ script: btc.Script.encode(['RETURN', data]), amount: BigInt(0) });
			tx.addOutputAddress(sbtcWalletAddress, BigInt(dust), net);
		} else {
			tx.addOutput({ script: sbtcWalletAddress, amount: BigInt(dust) });
		}
		const change = inputAmt(tx) - (dust);
		if (change > 0) tx.addOutputAddress(changeAddress, BigInt(change), net);
		//tx.sign(privKey);
		//tx.finalize();
		vsize = tx.vsize;
		const fees = [
			Math.floor(vsize * feeInfo['low_fee_per_kb'] / 1024),
			Math.floor(vsize * feeInfo['medium_fee_per_kb'] / 1024),
			Math.floor(vsize * feeInfo['high_fee_per_kb'] / 1024),
		]
		return fees;
	} catch (err:any) {
		return [ 850, 1000, 1150]
	}
}

/**
export function getWithdrawScript (network:string, data:Uint8Array, sbtcWalletAddress:string, fromBtcAddress:string):{type:string, script:Uint8Array} {
	const net = getNet(network);
	const addrScript = btc.Address(net).decode(sbtcWalletAddress)
	if (addrScript.type === 'wpkh') {
		return {
			type: 'wsh',
			script: btc.Script.encode([data, 'DROP', btc.p2wpkh(addrScript.hash).script])
		}
	} else if (addrScript.type === 'tr') {
		return {
			type: 'tr',
			//script: btc.Script.encode([data, 'DROP', btc.OutScript.encode(btc.Address(net).decode(this.fromBtcAddress)), 'CHECKSIG'])
			//script: btc.Script.encode([data, 'DROP', 'IF', 144, 'CHECKSEQUENCEVERIFY', 'DROP', btc.OutScript.encode(btc.Address(net).decode(this.fromBtcAddress)), 'CHECKSIG', 'ELSE', 'DUP', 'HASH160', sbtcWalletUint8, 'EQUALVERIFY', 'CHECKSIG', 'ENDIF'])
			//script: btc.Script.encode([data, 'DROP', btc.p2tr(hex.decode(pubkey2)).script])
			script: btc.Script.encode([data, 'DROP', btc.p2tr(addrScript.pubkey).script])
		}
	} else {
		const asmScript = btc.Script.encode([data, 'DROP', 
			'IF', 
			btc.OutScript.encode(btc.Address(net).decode(sbtcWalletAddress)),
			'ELSE', 
			144, 'CHECKSEQUENCEVERIFY', 'DROP',
			btc.OutScript.encode(btc.Address(net).decode(fromBtcAddress)),
			'CHECKSIG',
			'ENDIF'
		])
		return {
			type: 'tr',
			//script: btc.Script.encode([data, 'DROP', btc.OutScript.encode(btc.Address(net).decode(this.fromBtcAddress)), 'CHECKSIG'])
			//script: btc.Script.encode([data, 'DROP', 'IF', 144, 'CHECKSEQUENCEVERIFY', 'DROP', btc.OutScript.encode(btc.Address(net).decode(this.fromBtcAddress)), 'CHECKSIG', 'ELSE', 'DUP', 'HASH160', sbtcWalletUint8, 'EQUALVERIFY', 'CHECKSIG', 'ENDIF'])
			//script: btc.Script.encode([data, 'DROP', btc.p2tr(hex.decode(pubkey2)).script])
			script: btc.p2tr(asmScript).script
		}
	}
}
*/

  export function getBridgeWithdrawOpDrop(network:string, sbtcWalletPublicKey:string, uiPayload:WithdrawPayloadUIType, originator:string):BridgeTransactionType {
	const data = buildData(network, uiPayload.amountSats, uiPayload.signature!, true);
	const net = getNet(network);
	
	let pk1U = hex.decode(sbtcWalletPublicKey)
	let pk2U = hex.decode(uiPayload.reclaimPublicKey)
	if (pk1U.length === 33) pk1U = pk1U.subarray(1)
	if (pk2U.length === 33) pk2U = pk2U.subarray(1)

	const scripts =  [
	  { script: btc.Script.encode([hex.decode(data), 'DROP', pk1U, 'CHECKSIG']) },
	  { script: btc.Script.encode(['IF', 144, 'CHECKSEQUENCEVERIFY', 'DROP', pk2U, 'CHECKSIG', 'ENDIF']) }
	]
	const script = btc.p2tr(btc.TAPROOT_UNSPENDABLE_KEY, scripts, net, true);
	// convert unit8 arrays to hex strings for transportation.
	const commitTxScript = toStorable(script)
	const req:BridgeTransactionType = {
		network,
		originator,
		commitTxScript,
		uiPayload,
		status: 1,
		mode: 'op_drop',
		requestType: 'withdrawal',
		created: new Date().getTime(),
		updated: new Date().getTime()
	}
	return req;
  }
  
  export function getBridgeWithdraw(network:string, uiPayload:WithdrawPayloadUIType, originator:string):BridgeTransactionType {
	const req:BridgeTransactionType = {
		network,
		originator,
		uiPayload,
		status: 1,
		mode: 'op_return',
		requestType: 'withdrawal',
		created: new Date().getTime(),
		updated: new Date().getTime()
	}
	return req;
  }
  
  function buildData(network:string, amount:number, signature:string, opDrop:boolean):string {
	if (opDrop) return buildWithdrawPayloadOpDrop(network, amount, signature)
	return buildWithdrawPayload(network, amount, signature)
  }