feat(abstract-utxo): add wasm-utxo impl for explainPsbt

modules/abstract-utxo/src/replayProtection.ts

@@ -1,3 +1,4 @@
+import * as wasmUtxo from '@bitgo/wasm-utxo';
 import * as utxolib from '@bitgo/utxo-lib';
 
 export function getReplayProtectionAddresses(network: utxolib.Network): string[] {
@@ -13,6 +14,12 @@ export function getReplayProtectionAddresses(network: utxolib.Network): string[]
   return [];
 }
 
+export function getReplayProtectionOutputScripts(network: utxolib.Network): Buffer[] {
+  return getReplayProtectionAddresses(network).map((address) =>
+    Buffer.from(wasmUtxo.utxolibCompat.toOutputScript(address, network))
+  );
+}
+
 export function isReplayProtectionUnspent<TNumber extends number | bigint>(
   u: utxolib.bitgo.Unspent<TNumber>,
   network: utxolib.Network

modules/abstract-utxo/src/transaction/explainTransaction.ts

@@ -1,13 +1,16 @@
 import * as utxolib from '@bitgo/utxo-lib';
-import { isTriple, IWallet } from '@bitgo/sdk-core';
+import { fixedScriptWallet } from '@bitgo/wasm-utxo';
+import { isTriple, IWallet, Triple } from '@bitgo/sdk-core';
 
 import { getDescriptorMapFromWallet, isDescriptorWallet } from '../descriptor';
 import { toBip32Triple } from '../keychains';
 import { getPolicyForEnv } from '../descriptor/validatePolicy';
+import { getReplayProtectionOutputScripts } from '../replayProtection';
 
 import type {
   TransactionExplanationUtxolibLegacy,
   TransactionExplanationUtxolibPsbt,
+  TransactionExplanationWasm,
 } from './fixedScript/explainTransaction';
 import * as fixedScript from './fixedScript';
 import * as descriptor from './descriptor';
@@ -17,15 +20,15 @@ import * as descriptor from './descriptor';
  * change amounts, and transaction outputs.
  */
 export function explainTx<TNumber extends number | bigint>(
-  tx: utxolib.bitgo.UtxoTransaction<TNumber> | utxolib.bitgo.UtxoPsbt,
+  tx: utxolib.bitgo.UtxoTransaction<TNumber> | utxolib.bitgo.UtxoPsbt | fixedScriptWallet.BitGoPsbt,
   params: {
     wallet?: IWallet;
     pubs?: string[];
     txInfo?: { unspents?: utxolib.bitgo.Unspent<TNumber>[] };
     changeInfo?: fixedScript.ChangeAddressInfo[];
   },
   network: utxolib.Network
-): TransactionExplanationUtxolibLegacy | TransactionExplanationUtxolibPsbt {
+): TransactionExplanationUtxolibLegacy | TransactionExplanationUtxolibPsbt | TransactionExplanationWasm {
   if (params.wallet && isDescriptorWallet(params.wallet)) {
     if (tx instanceof utxolib.bitgo.UtxoPsbt) {
       if (!params.pubs || !isTriple(params.pubs)) {
@@ -44,6 +47,25 @@ export function explainTx<TNumber extends number | bigint>(
   }
   if (tx instanceof utxolib.bitgo.UtxoPsbt) {
     return fixedScript.explainPsbt(tx, params, network);
+  } else if (tx instanceof fixedScriptWallet.BitGoPsbt) {
+    const pubs = params.pubs;
+    if (!pubs) {
+      throw new Error('pub triple is required');
+    }
+    const walletXpubs: Triple<string> | undefined =
+      pubs instanceof utxolib.bitgo.RootWalletKeys
+        ? (pubs.triple.map((k) => k.neutered().toBase58()) as Triple<string>)
+        : isTriple(pubs)
+        ? (pubs as Triple<string>)
+        : undefined;
+    if (!walletXpubs) {
+      throw new Error('pub triple must be valid triple or RootWalletKeys');
+    }
+    return fixedScript.explainPsbtWasm(tx, walletXpubs, {
+      replayProtection: {
+        outputScripts: getReplayProtectionOutputScripts(network),
+      },
+    });
   } else {
     return fixedScript.explainLegacyTx(tx, params, network);
   }

modules/abstract-utxo/src/transaction/fixedScript/explainPsbtWasm.ts

@@ -0,0 +1,60 @@
+import { fixedScriptWallet } from '@bitgo/wasm-utxo';
+import { Triple } from '@bitgo/sdk-core';
+
+import type { Output, FixedScriptWalletOutput } from '../../abstractUtxoCoin';
+
+import type { TransactionExplanationWasm } from './explainTransaction';
+
+function scriptToAddress(script: Uint8Array): string {
+  return `scriptPubKey:${Buffer.from(script).toString('hex')}`;
+}
+
+export function explainPsbtWasm(
+  psbt: fixedScriptWallet.BitGoPsbt,
+  walletXpubs: Triple<string>,
+  params: {
+    replayProtection: {
+      checkSignature?: boolean;
+      outputScripts: Buffer[];
+    };
+  }
+): TransactionExplanationWasm {
+  const parsed = psbt.parseTransactionWithWalletKeys(walletXpubs, params.replayProtection);
+
+  const changeOutputs: FixedScriptWalletOutput[] = [];
+  const outputs: Output[] = [];
+
+  parsed.outputs.forEach((output) => {
+    const address = output.address ?? scriptToAddress(output.script);
+
+    if (output.scriptId) {
+      // This is a change output
+      changeOutputs.push({
+        address,
+        amount: output.value.toString(),
+        chain: output.scriptId.chain,
+        index: output.scriptId.index,
+        external: false,
+      });
+    } else {
+      // This is an external output
+      outputs.push({
+        address,
+        amount: output.value.toString(),
+        external: true,
+      });
+    }
+  });
+
+  const changeAmount = changeOutputs.reduce((sum, output) => sum + BigInt(output.amount), BigInt(0));
+  const outputAmount = outputs.reduce((sum, output) => sum + BigInt(output.amount), BigInt(0));
+
+  return {
+    id: psbt.unsignedTxid(),
+    outputAmount: outputAmount.toString(),
+    changeAmount: changeAmount.toString(),
+    outputs,
+    changeOutputs,
+    fee: parsed.minerFee.toString(),
+  };
+}

modules/abstract-utxo/src/transaction/fixedScript/explainTransaction.ts

@@ -41,13 +41,19 @@ interface TransactionExplanationWithSignatures<TFee = string> extends AbstractUt
   signatures: number;
 }
 
+/** For our wasm backend, we do not return the deprecated fields. We set TFee to string for backwards compatibility. */
+export type TransactionExplanationWasm = AbstractUtxoTransactionExplanation<string>;
+
 /** When parsing the legacy transaction format, we cannot always infer the fee so we set it to string | undefined */
 export type TransactionExplanationUtxolibLegacy = TransactionExplanationWithSignatures<string | undefined>;
 
 /** When parsing a PSBT, we can infer the fee so we set TFee to string. */
 export type TransactionExplanationUtxolibPsbt = TransactionExplanationWithSignatures<string>;
 
-export type TransactionExplanation = TransactionExplanationUtxolibLegacy | TransactionExplanationUtxolibPsbt;
+export type TransactionExplanation =
+  | TransactionExplanationUtxolibLegacy
+  | TransactionExplanationUtxolibPsbt
+  | TransactionExplanationWasm;
 
 export type ChangeAddressInfo = {
   address: string;

modules/abstract-utxo/src/transaction/fixedScript/index.ts

@@ -1,4 +1,5 @@
 export { explainPsbt, explainLegacyTx, ChangeAddressInfo } from './explainTransaction';
+export { explainPsbtWasm } from './explainPsbtWasm';
 export { parseTransaction } from './parseTransaction';
 export { CustomChangeOptions } from './parseOutput';
 export { verifyTransaction } from './verifyTransaction';

modules/abstract-utxo/test/unit/transaction/fixedScript/explainPsbt.ts

@@ -1,18 +1,31 @@
 import assert from 'node:assert/strict';
 
+import * as utxolib from '@bitgo/utxo-lib';
 import { testutil } from '@bitgo/utxo-lib';
+import { fixedScriptWallet, Triple } from '@bitgo/wasm-utxo';
 
 import type { TransactionExplanation } from '../../../../src/transaction/fixedScript/explainTransaction';
-import { explainPsbt } from '../../../../src/transaction/fixedScript';
+import { explainPsbt, explainPsbtWasm } from '../../../../src/transaction/fixedScript';
+
+function hasWasmUtxoSupport(network: utxolib.Network): boolean {
+  return ![
+    utxolib.networks.bitcoincash,
+    utxolib.networks.bitcoingold,
+    utxolib.networks.ecash,
+    utxolib.networks.zcash,
+  ].includes(utxolib.getMainnet(network));
+}
 
 function describeTransactionWith(acidTest: testutil.AcidTest) {
   describe(`${acidTest.name}`, function () {
+    let psbtBytes: Buffer;
     let refExplanation: TransactionExplanation;
     before('prepare', function () {
       const psbt = acidTest.createPsbt();
       refExplanation = explainPsbt(psbt, { pubs: acidTest.rootWalletKeys }, acidTest.network, {
         strict: true,
       });
+      psbtBytes = psbt.toBuffer();
     });
 
     it('should match the expected values for explainPsbt', function () {
@@ -26,9 +39,41 @@ function describeTransactionWith(acidTest: testutil.AcidTest) {
         assert.strictEqual(typeof change.address, 'string');
       });
     });
+
+    it('should match explainPsbtWasm', function () {
+      if (!hasWasmUtxoSupport(acidTest.network)) {
+        return this.skip();
+      }
+
+      const networkName = utxolib.getNetworkName(acidTest.network);
+      assert(networkName);
+      const wasmPsbt = fixedScriptWallet.BitGoPsbt.fromBytes(psbtBytes, networkName);
+      const walletXpubs = acidTest.rootWalletKeys.triple.map((k) => k.neutered().toBase58()) as Triple<string>;
+      const wasmExplanation = explainPsbtWasm(wasmPsbt, walletXpubs, {
+        replayProtection: {
+          outputScripts: [acidTest.getReplayProtectionOutputScript()],
+        },
+      });
+
+      for (const key of Object.keys(refExplanation)) {
+        const refValue = refExplanation[key];
+        const wasmValue = wasmExplanation[key];
+        switch (key) {
+          case 'displayOrder':
+          case 'inputSignatures':
+          case 'signatures':
+            // these are deprecated fields that we want to get rid of
+            assert.deepStrictEqual(wasmValue, undefined);
+            break;
+          default:
+            assert.deepStrictEqual(wasmValue, refValue, `mismatch for key ${key}`);
+            break;
+        }
+      }
+    });
   });
 }
 
-describe('explainPsbt', function () {
+describe('explainPsbt(Wasm)', function () {
   testutil.AcidTest.suite().forEach((test) => describeTransactionWith(test));
 });