feat: modify protocol fee calculation (#6)

* v1.0.8

* feat: modify protocol fee calculation

package.json

@@ -1,7 +1,7 @@
 {
   "type": "module",
   "name": "dlc-btc-lib",
-  "version": "1.0.7",
+  "version": "1.0.9",
   "description": "This library provides a comprehensive set of interfaces and functions for minting dlcBTC tokens on supported blockchains.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",

src/functions/bitcoin/bitcoin-functions.ts

@@ -15,6 +15,7 @@ import { taprootTweakPubkey } from '@scure/btc-signer/utils';
 import { BIP32Factory, BIP32Interface } from 'bip32';
 import { Network } from 'bitcoinjs-lib';
 import { bitcoin, regtest, testnet } from 'bitcoinjs-lib/src/networks.js';
+import { Decimal } from 'decimal.js';
 import * as ellipticCurveCryptography from 'tiny-secp256k1';
 
 import {
@@ -33,6 +34,11 @@ const ECDSA_PUBLIC_KEY_LENGTH = 33;
 
 const bip32 = BIP32Factory(ellipticCurveCryptography);
 
+export function getFeeAmount(bitcoinAmount: number, feeBasisPoints: number): number {
+  const feePercentage = new Decimal(feeBasisPoints).dividedBy(100);
+  return new Decimal(bitcoinAmount).times(feePercentage.dividedBy(100)).toNumber();
+}
+
 /**
  * Derives the Public Key at the Unhardened Path (0/0) from a given Extended Public Key.
  * @param extendedPublicKey - The base58-encoded Extended Public Key.

src/functions/bitcoin/psbt-functions.ts

@@ -1,5 +1,5 @@
 import { hexToBytes } from '@noble/hashes/utils';
-import { p2wpkh, selectUTXO } from '@scure/btc-signer';
+import { selectUTXO } from '@scure/btc-signer';
 import { P2Ret, P2TROut } from '@scure/btc-signer/payment';
 import { Network, Psbt } from 'bitcoinjs-lib';
 import { PartialSignature } from 'ledger-bitcoin/build/main/lib/appClient.js';
@@ -8,6 +8,7 @@ import { BitcoinInputSigningConfig, PaymentTypes } from '../../models/bitcoin-mo
 import { reverseBytes } from '../../utilities/index.js';
 import {
   ecdsaPublicKeyToSchnorr,
+  getFeeAmount,
   getFeeRecipientAddressFromPublicKey,
   getUTXOs,
 } from '../bitcoin/bitcoin-functions.js';
@@ -35,15 +36,15 @@ export async function createFundingTransaction(
   bitcoinBlockchainAPIURL: string
 ): Promise<Uint8Array> {
   const feeAddress = getFeeRecipientAddressFromPublicKey(feePublicKey, bitcoinNetwork);
-  const feeRecipientOutputValue = bitcoinAmount / feeBasisPoints;
+  const feeAmount = getFeeAmount(Number(bitcoinAmount), Number(feeBasisPoints));
 
   const userUTXOs = await getUTXOs(bitcoinNativeSegwitTransaction, bitcoinBlockchainAPIURL);
 
   const psbtOutputs = [
     { address: multisigAddress, amount: bitcoinAmount },
     {
       address: feeAddress,
-      amount: feeRecipientOutputValue,
+      amount: BigInt(feeAmount),
     },
   ];
 
@@ -59,6 +60,10 @@ export async function createFundingTransaction(
 
   if (!fundingTX) throw new Error('Could not create Funding Transaction');
 
+  fundingTX.updateInput(0, {
+    sequence: 0xfffffff0,
+  });
+
   const fundingPSBT = fundingTX.toPSBT();
 
   return fundingPSBT;
@@ -89,10 +94,8 @@ export function createClosingTransaction(
   feePublicKey: string,
   feeBasisPoints: bigint
 ): Uint8Array {
-  const feePublicKeyBuffer = Buffer.from(feePublicKey, 'hex');
-  const { address: feeAddress } = p2wpkh(feePublicKeyBuffer, bitcoinNetwork);
-
-  if (!feeAddress) throw new Error('Could not create Fee Address');
+  const feeAddress = getFeeRecipientAddressFromPublicKey(feePublicKey, bitcoinNetwork);
+  const feeAmount = getFeeAmount(Number(bitcoinAmount), Number(feeBasisPoints));
 
   const inputs = [
     {
@@ -109,7 +112,7 @@ export function createClosingTransaction(
   const outputs = [
     {
       address: feeAddress,
-      amount: bitcoinAmount / feeBasisPoints,
+      amount: BigInt(feeAmount),
     },
   ];
 
@@ -121,9 +124,15 @@ export function createClosingTransaction(
     network: bitcoinNetwork,
   });
 
-  if (!selected?.tx) throw new Error('Could not create Closing Transaction');
+  const closingTX = selected?.tx;
+
+  if (!closingTX) throw new Error('Could not create Closing Transaction');
+
+  closingTX.updateInput(0, {
+    sequence: 0xfffffff0,
+  });
 
-  const closingPSBT = selected.tx.toPSBT();
+  const closingPSBT = closingTX.toPSBT();
 
   return closingPSBT;
 }