refactor(sdk-coin-flrp): update flrp txn builders to use etna support

Ticket: WIN-8498

Author: mohd-kashif

modules/sdk-coin-flrp/package.json

@@ -47,6 +47,7 @@
     "@bitgo/sdk-test": "^9.1.20"
   },
   "dependencies": {
+    "@bitgo/public-types": "5.59.0",
     "@bitgo/sdk-core": "^36.25.0",
     "@bitgo/secp256k1": "^1.8.0",
     "@bitgo/statics": "^58.19.0",

modules/sdk-coin-flrp/src/lib/ExportInCTxBuilder.ts

@@ -5,47 +5,30 @@ import {
   evmSerial,
   UnsignedTx,
   Credential,
-  BigIntPr,
-  Int,
-  Id,
-  TransferableOutput,
   Address,
   TransferOutput,
-  OutputOwners,
   utils as FlareUtils,
+  evm,
 } from '@flarenetwork/flarejs';
 import utils from './utils';
-import { DecodedUtxoObj, Tx, FlareTransactionType } from './iface';
+import { Tx, FlareTransactionType, ExportEVMOptions } from './iface';
 
 export class ExportInCTxBuilder extends AtomicInCTransactionBuilder {
-  private _amount: bigint;
   private _nonce: bigint;
 
   constructor(_coinConfig: Readonly<CoinConfig>) {
     super(_coinConfig);
   }
 
   /**
-   * Utxos are not required in Export Tx in C-Chain.
-   * Override utxos to prevent used by throwing a error.
+   * UTXOs are not required for Export Tx from C-Chain (uses EVM balance instead).
+   * Override to prevent usage by throwing an error.
    *
-   * @param {DecodedUtxoObj[]} value ignored
+   * @param {string[]} _utxoHexStrings - ignored, UTXOs not used for C-chain exports
+   * @throws {BuildTransactionError} always throws as UTXOs are not applicable
    */
-  utxos(value: DecodedUtxoObj[]): this {
-    throw new BuildTransactionError('utxos are not required in Export Tx in C-Chain');
-  }
-
-  /**
-   * Amount is a bigint that specifies the quantity of the asset that this output owns. Must be positive.
-   * The transaction output amount add a fixed fee that will be paid upon import.
-   *
-   * @param {bigint | string} amount The withdrawal amount
-   */
-  amount(amount: bigint | string): this {
-    const amountBigInt = typeof amount === 'string' ? BigInt(amount) : amount;
-    this.validateAmount(amountBigInt);
-    this._amount = amountBigInt;
-    return this;
+  utxos(_utxoHexStrings: string[]): this {
+    throw new BuildTransactionError('UTXOs are not required for Export Tx from C-Chain');
   }
 
   /**
@@ -81,8 +64,6 @@ export class ExportInCTxBuilder extends AtomicInCTransactionBuilder {
       throw new NotSupported('Transaction cannot be parsed or has an unsupported transaction type');
     }
 
-    // The outputs is a multisign P-Chain address result.
-    // It's expected to have only one output to the destination P-Chain address.
     const outputs = baseTx.exportedOutputs;
     if (outputs.length !== 1) {
       throw new BuildTransactionError('Transaction can have one output');
@@ -93,8 +74,6 @@ export class ExportInCTxBuilder extends AtomicInCTransactionBuilder {
       throw new BuildTransactionError('AssetID mismatch');
     }
 
-    // The inputs is not an utxo.
-    // It's expected to have only one input from C-Chain address.
     const inputs = baseTx.ins;
     if (inputs.length !== 1) {
       throw new BuildTransactionError('Transaction can have one input');
@@ -107,27 +86,17 @@ export class ExportInCTxBuilder extends AtomicInCTransactionBuilder {
     const inputAmount = input.amount.value();
     const outputAmount = transferOutput.amount();
     const fee = inputAmount - outputAmount;
-    this._amount = outputAmount;
-    // Subtract fixedFee from total fee to get the gas-based feeRate
-    // buildFlareTransaction will add fixedFee back when building the transaction
-    this.transaction._fee.feeRate = Number(fee) - Number(this.fixedFee);
+    this.transaction._amount = outputAmount;
     this.transaction._fee.fee = fee.toString();
-    this.transaction._fee.size = 1;
     this.transaction._fromAddresses = [Buffer.from(input.address.toBytes())];
     this.transaction._locktime = transferOutput.getLocktime();
-
     this._nonce = input.nonce.value();
-
-    // Use credentials passed from TransactionBuilderFactory (properly extracted using codec)
     const credentials = parsedCredentials || [];
     const hasCredentials = credentials.length > 0;
-
-    // If it's a signed transaction, store the original raw bytes to preserve exact format
     if (hasCredentials && rawBytes) {
       this.transaction._rawSignedBytes = rawBytes;
     }
 
-    // Create proper UnsignedTx wrapper with credentials
     const fromAddress = new Address(this.transaction._fromAddresses[0]);
     const addressMap = new FlareUtils.AddressMap([
       [fromAddress, 0],
@@ -160,80 +129,52 @@ export class ExportInCTxBuilder extends AtomicInCTransactionBuilder {
    */
   protected buildFlareTransaction(): void {
     if (this.transaction.hasCredentials) return;
-    if (this._amount === undefined) {
-      throw new Error('amount is required');
+    if (this.transaction._amount === undefined) {
+      throw new BuildTransactionError('amount is required');
     }
     if (this.transaction._fromAddresses.length !== 1) {
-      throw new Error('sender is one and required');
+      throw new BuildTransactionError('sender is one and required');
     }
     if (this.transaction._to.length === 0) {
-      throw new Error('to is required');
+      throw new BuildTransactionError('to is required');
     }
-    if (!this.transaction._fee.feeRate) {
-      throw new Error('fee rate is required');
+    if (!this.transaction._fee.fee) {
+      throw new BuildTransactionError('fee rate is required');
     }
     if (this._nonce === undefined) {
-      throw new Error('nonce is required');
+      throw new BuildTransactionError('nonce is required');
+    }
+    if (!this.transaction._context) {
+      throw new BuildTransactionError('context is required');
     }
 
-    // For EVM exports, total fee = feeRate (gas-based fee) + fixedFee (P-chain import fee)
-    // This matches the AVAX implementation where fixedFee covers the import cost
-    const txFee = BigInt(this.fixedFee);
-    const fee = BigInt(this.transaction._fee.feeRate) + txFee;
-    this.transaction._fee.fee = fee.toString();
-    this.transaction._fee.size = 1;
-
+    const fee = BigInt(this.transaction._fee.fee);
     const fromAddressBytes = this.transaction._fromAddresses[0];
-    const fromAddress = new Address(fromAddressBytes);
-    const assetId = utils.flareIdString(this.transaction._assetId);
-    const amount = new BigIntPr(this._amount + fee);
-    const nonce = new BigIntPr(this._nonce);
-    const input = new evmSerial.Input(fromAddress, amount, assetId, nonce);
-    // Map all destination P-chain addresses for multisig support
-    // Sort addresses alphabetically by hex representation (required by Avalanche/Flare protocol)
     const sortedToAddresses = [...this.transaction._to].sort((a, b) => {
       const aHex = Buffer.from(a).toString('hex');
       const bHex = Buffer.from(b).toString('hex');
       return aHex.localeCompare(bHex);
     });
     const toAddresses = sortedToAddresses.map((addr) => new Address(addr));
 
-    const exportTx = new evmSerial.ExportTx(
-      new Int(this.transaction._networkID),
-      utils.flareIdString(this.transaction._blockchainID),
-      new Id(new Uint8Array(this._externalChainId)),
-      [input],
-      [
-        new TransferableOutput(
-          assetId,
-          new TransferOutput(
-            new BigIntPr(this._amount),
-            new OutputOwners(
-              new BigIntPr(this.transaction._locktime),
-              new Int(this.transaction._threshold),
-              toAddresses
-            )
-          )
-        ),
-      ]
-    );
-
-    // Create address maps with proper EVM address format
-    const addressMap = new FlareUtils.AddressMap([
-      [fromAddress, 0],
-      [fromAddress, 1], // Map the same address to both indices since it's used in both places
-    ]);
-    const addressMaps = new FlareUtils.AddressMaps([addressMap]); // Single map is sufficient
-
-    // Create unsigned transaction with proper address mapping
-    const unsignedTx = new UnsignedTx(
-      exportTx,
-      [], // Empty UTXOs array, will be filled during processing
-      addressMaps,
-      [new Credential([utils.createNewSig('')])] // Empty credential for signing
+    const exportEVMOptions: ExportEVMOptions = {
+      threshold: this.transaction._threshold,
+      locktime: this.transaction._locktime,
+    };
+
+    const exportTx = evm.newExportTxFromBaseFee(
+      this.transaction._context,
+      fee / BigInt(1e9),
+      this.transaction._amount,
+      this.transaction._context.pBlockchainID,
+      fromAddressBytes,
+      toAddresses.map((addr) => Buffer.from(addr.toBytes())),
+      BigInt(this._nonce),
+      utils.flareIdString(this.transaction._assetId).toString(),
+      exportEVMOptions
     );
 
-    this.transaction.setTransaction(unsignedTx);
+    this.transaction.setTransaction(exportTx);
   }
 
   /**