feat: abstract dlc handler (#46)

* feat: add abstract dlc handler

package.json

@@ -1,7 +1,7 @@
 {
   "type": "module",
   "name": "dlc-btc-lib",
-  "version": "2.4.21",
+  "version": "2.5.0",
   "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/constants/dlc-handler.constants.ts

@@ -0,0 +1,7 @@
+export const DLCHandlers = {
+  KEYPAIR: 'keypair',
+  LEATHER: 'leather',
+  UNISAT_FORDEFI: 'unisat/fordefi',
+  LEDGER: 'ledger',
+  DFNS: 'dfns',
+} as const;

src/dlc-handlers/abstract-dlc-handler.ts

@@ -0,0 +1,252 @@
+import { Transaction } from '@scure/btc-signer';
+import { P2Ret, P2TROut } from '@scure/btc-signer/payment';
+import { Network } from 'bitcoinjs-lib';
+
+import {
+  createNativeSegwitPayment,
+  createTaprootMultisigPayment,
+  createTaprootPayment,
+  deriveUnhardenedPublicKey,
+  ecdsaPublicKeyToSchnorr,
+  finalizeUserInputs,
+  getBalance,
+  getFeeRate,
+  getUnspendableKeyCommittedToUUID,
+} from '../functions/bitcoin/bitcoin-functions.js';
+import {
+  createDepositTransaction,
+  createFundingTransaction,
+  createWithdrawTransaction,
+} from '../functions/bitcoin/psbt-functions.js';
+import { PaymentInformation } from '../models/bitcoin-models.js';
+import {
+  DLCHandlerType,
+  FundingPaymentType,
+  PaymentType,
+  TransactionType,
+} from '../models/dlc-handler.models.js';
+import {
+  AddressNotFoundError,
+  InsufficientFundsError,
+  InvalidPaymentTypeError,
+  PaymentNotSetError,
+} from '../models/errors/dlc-handler.errors.models.js';
+import { RawVault } from '../models/ethereum-models.js';
+
+export abstract class AbstractDLCHandler {
+  abstract readonly dlcHandlerType: DLCHandlerType;
+  protected fundingPaymentType: FundingPaymentType;
+  protected _payment?: PaymentInformation;
+  protected readonly bitcoinNetwork: Network;
+  protected readonly bitcoinBlockchainAPI: string;
+  protected readonly bitcoinBlockchainFeeRecommendationAPI: string;
+
+  constructor(
+    fundingPaymentType: FundingPaymentType,
+    bitcoinNetwork: Network,
+    bitcoinBlockchainAPI: string,
+    bitcoinBlockchainFeeRecommendationAPI: string
+  ) {
+    this.fundingPaymentType = fundingPaymentType;
+    this.bitcoinNetwork = bitcoinNetwork;
+    this.bitcoinBlockchainAPI = bitcoinBlockchainAPI;
+    this.bitcoinBlockchainFeeRecommendationAPI = bitcoinBlockchainFeeRecommendationAPI;
+  }
+
+  protected set payment(payment: PaymentInformation) {
+    this._payment = payment;
+  }
+
+  protected get payment(): PaymentInformation {
+    if (!this._payment) {
+      throw new PaymentNotSetError();
+    }
+    return this._payment;
+  }
+
+  getVaultRelatedAddress(paymentType: PaymentType): string {
+    switch (paymentType) {
+      case 'funding':
+        if (!this.payment.fundingPayment.address) {
+          throw new AddressNotFoundError('funding');
+        }
+        return this.payment.fundingPayment.address;
+      case 'multisig':
+        if (!this.payment.multisigPayment.address) {
+          throw new AddressNotFoundError('multisig');
+        }
+        return this.payment.multisigPayment.address;
+      default:
+        throw new InvalidPaymentTypeError(paymentType);
+    }
+  }
+
+  protected async createPaymentInformation(
+    vaultUUID: string,
+    attestorGroupPublicKey: string
+  ): Promise<PaymentInformation> {
+    let fundingPayment: P2Ret | P2TROut;
+
+    if (this.fundingPaymentType === 'wpkh') {
+      const fundingPublicKeyBuffer = Buffer.from(this.getUserFundingPublicKey(), 'hex');
+      fundingPayment = createNativeSegwitPayment(fundingPublicKeyBuffer, this.bitcoinNetwork);
+    } else {
+      const fundingPublicKeyBuffer = Buffer.from(this.getUserFundingPublicKey(), 'hex');
+      const fundingSchnorrPublicKeyBuffer = ecdsaPublicKeyToSchnorr(fundingPublicKeyBuffer);
+      fundingPayment = createTaprootPayment(fundingSchnorrPublicKeyBuffer, this.bitcoinNetwork);
+    }
+
+    const unspendablePublicKey = getUnspendableKeyCommittedToUUID(vaultUUID, this.bitcoinNetwork);
+    const unspendableDerivedPublicKey = deriveUnhardenedPublicKey(
+      unspendablePublicKey,
+      this.bitcoinNetwork
+    );
+
+    const attestorDerivedPublicKey = deriveUnhardenedPublicKey(
+      attestorGroupPublicKey,
+      this.bitcoinNetwork
+    );
+
+    const taprootPublicKeyBuffer = Buffer.from(this.getUserTaprootPublicKey(), 'hex');
+
+    const multisigPayment = createTaprootMultisigPayment(
+      unspendableDerivedPublicKey,
+      attestorDerivedPublicKey,
+      taprootPublicKeyBuffer,
+      this.bitcoinNetwork
+    );
+
+    const paymentInformation = { fundingPayment, multisigPayment };
+
+    this.payment = paymentInformation;
+    return paymentInformation;
+  }
+
+  private async validateFundsAvailability(
+    fundingPayment: P2Ret | P2TROut,
+    requiredAmount: bigint
+  ): Promise<void> {
+    const currentBalance = BigInt(await getBalance(fundingPayment, this.bitcoinBlockchainAPI));
+
+    if (currentBalance < requiredAmount) {
+      throw new InsufficientFundsError(currentBalance, requiredAmount);
+    }
+  }
+
+  private async getFeeRate(feeRateMultiplier?: number, customFeeRate?: bigint): Promise<bigint> {
+    return (
+      customFeeRate ??
+      BigInt(await getFeeRate(this.bitcoinBlockchainFeeRecommendationAPI, feeRateMultiplier))
+    );
+  }
+
+  async createFundingPSBT(
+    vault: RawVault,
+    depositAmount: bigint,
+    attestorGroupPublicKey: string,
+    feeRateMultiplier?: number,
+    customFeeRate?: bigint
+  ): Promise<Transaction> {
+    const { fundingPayment, multisigPayment } = await this.createPaymentInformation(
+      vault.uuid,
+      attestorGroupPublicKey
+    );
+
+    const feeRate = await this.getFeeRate(feeRateMultiplier, customFeeRate);
+
+    await this.validateFundsAvailability(fundingPayment, vault.valueLocked.toBigInt());
+
+    return await createFundingTransaction(
+      this.bitcoinBlockchainAPI,
+      this.bitcoinNetwork,
+      depositAmount,
+      multisigPayment,
+      fundingPayment,
+      feeRate,
+      vault.btcFeeRecipient,
+      vault.btcMintFeeBasisPoints.toBigInt()
+    );
+  }
+
+  async createWithdrawPSBT(
+    vault: RawVault,
+    withdrawAmount: bigint,
+    attestorGroupPublicKey: string,
+    fundingTransactionID: string,
+    feeRateMultiplier?: number,
+    customFeeRate?: bigint
+  ): Promise<Transaction> {
+    const { fundingPayment, multisigPayment } = await this.createPaymentInformation(
+      vault.uuid,
+      attestorGroupPublicKey
+    );
+
+    const feeRate = await this.getFeeRate(feeRateMultiplier, customFeeRate);
+
+    return await createWithdrawTransaction(
+      this.bitcoinBlockchainAPI,
+      this.bitcoinNetwork,
+      withdrawAmount,
+      fundingTransactionID,
+      multisigPayment,
+      fundingPayment,
+      feeRate,
+      vault.btcFeeRecipient,
+      vault.btcRedeemFeeBasisPoints.toBigInt()
+    );
+  }
+
+  async createDepositPSBT(
+    vault: RawVault,
+    depositAmount: bigint,
+    attestorGroupPublicKey: string,
+    fundingTransactionID: string,
+    feeRateMultiplier?: number,
+    customFeeRate?: bigint
+  ): Promise<Transaction> {
+    const { fundingPayment, multisigPayment } = await this.createPaymentInformation(
+      vault.uuid,
+      attestorGroupPublicKey
+    );
+
+    const feeRate = await this.getFeeRate(feeRateMultiplier, customFeeRate);
+
+    return await createDepositTransaction(
+      this.bitcoinBlockchainAPI,
+      this.bitcoinNetwork,
+      depositAmount,
+      fundingTransactionID,
+      multisigPayment,
+      fundingPayment,
+      feeRate,
+      vault.btcFeeRecipient,
+      vault.btcMintFeeBasisPoints.toBigInt()
+    );
+  }
+
+  private readonly transactionFinalizers: Record<
+    TransactionType,
+    (transaction: Transaction, payment: P2Ret | P2TROut) => void
+  > = {
+    funding: transaction => transaction.finalize(),
+    deposit: (transaction, payment) => finalizeUserInputs(transaction, payment),
+    withdraw: () => {},
+  };
+
+  protected finalizeTransaction(
+    signedTransaction: Transaction,
+    transactionType: TransactionType,
+    fundingPayment: P2Ret | P2TROut
+  ): void {
+    this.transactionFinalizers[transactionType](signedTransaction, fundingPayment);
+  }
+
+  abstract signPSBT(
+    transaction: Transaction,
+    transactionType: TransactionType
+  ): Promise<Transaction>;
+
+  abstract getUserTaprootPublicKey(tweaked?: boolean): string;
+
+  abstract getUserFundingPublicKey(): string;
+}