Merge pull request #6895 from BitGo/WIN-6321

feat: (skeleton) export tx builder for p chain

Author: yogeshwar-bitgo

modules/sdk-coin-flrp/package.json

@@ -44,13 +44,13 @@
   },
   "devDependencies": {
     "@types/bn.js": "^5.2.0",
-    "@bitgo/sdk-test": "^9.0.5",
-    "@bitgo/sdk-api": "^1.67.0"
+    "@bitgo/sdk-test": "^9.0.9",
+    "@bitgo/sdk-api": "^1.68.3"
   },
   "dependencies": {
-    "@bitgo/sdk-core": "^36.5.0",
+    "@bitgo/sdk-core": "^36.8.0",
     "@bitgo/secp256k1": "^1.5.0",
-    "@bitgo/statics": "^57.5.0",
+    "@bitgo/statics": "^57.8.0",
     "@flarenetwork/flarejs": "4.1.0-rc0",
     "@noble/curves": "1.8.1",
     "create-hash": "^1.2.0",

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

@@ -0,0 +1,67 @@
+import { BaseCoin as CoinConfig } from '@bitgo/statics';
+import { BuildTransactionError, TransactionType } from '@bitgo/sdk-core';
+
+/**
+ * Minimal placeholder for Flare P-chain atomic transaction building.
+ * This will be expanded with proper Flare P-chain logic (inputs/outputs/credentials, UTXO handling, fees, etc.).
+ */
+export abstract class AtomicTransactionBuilder {
+  protected readonly _coinConfig: Readonly<CoinConfig>;
+  // External chain id (destination) for export transactions
+  protected _externalChainId: Buffer | undefined;
+
+  // Simplified internal transaction state (mirrors shape expected by existing builders)
+  // Simplified internal transaction state
+  protected transaction: {
+    _network: Record<string, unknown>;
+    _networkID: number;
+    _blockchainID: Buffer;
+    _assetId: Buffer;
+    _fromAddresses: string[];
+    _locktime: bigint;
+    _threshold: number;
+    fee: { fee: string };
+    hasCredentials: boolean;
+    _tx?: unknown;
+    setTransaction: (tx: unknown) => void;
+  } = {
+    _network: {},
+    _networkID: 0,
+    _blockchainID: Buffer.alloc(0),
+    _assetId: Buffer.alloc(0),
+    _fromAddresses: [],
+    _locktime: 0n,
+    _threshold: 1,
+    fee: { fee: '0' },
+    hasCredentials: false,
+    setTransaction: function (_tx: unknown) {
+      this._tx = _tx;
+    },
+  };
+
+  constructor(coinConfig: Readonly<CoinConfig>) {
+    this._coinConfig = coinConfig;
+  }
+
+  protected abstract get transactionType(): TransactionType;
+
+  validateAmount(amount: bigint): void {
+    if (amount <= 0n) {
+      throw new BuildTransactionError('Amount must be positive');
+    }
+  }
+
+  /**
+   * Placeholder that should assemble inputs/outputs and credentials once UTXO + key logic is implemented.
+   */
+  protected createInputOutput(_total: bigint): { inputs: unknown[]; outputs: unknown[]; credentials: unknown[] } {
+    return { inputs: [], outputs: [], credentials: [] };
+  }
+
+  /**
+   * Base initBuilder used by concrete builders. For now just returns this so fluent API works.
+   */
+  initBuilder(_tx: unknown): this {
+    return this;
+  }
+}

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

@@ -0,0 +1,61 @@
+import { BaseCoin as CoinConfig } from '@bitgo/statics';
+import { TransactionType } from '@bitgo/sdk-core';
+import { AtomicTransactionBuilder } from './atomicTransactionBuilder';
+
+export class ExportTxBuilder extends AtomicTransactionBuilder {
+  private _amount = 0n;
+
+  constructor(_coinConfig: Readonly<CoinConfig>) {
+    super(_coinConfig);
+  }
+
+  protected get transactionType(): TransactionType {
+    return TransactionType.Export;
+  }
+
+  /**
+   * Amount is a long that specifies the quantity of the asset that this output owns. Must be positive.
+   *
+   * @param {BN | string} amount The withdrawal amount
+   */
+  amount(value: bigint | string | number): this {
+    const v = typeof value === 'bigint' ? value : BigInt(value);
+    this.validateAmount(v);
+    this._amount = v;
+    return this;
+  }
+
+  /** @inheritdoc */
+  // Placeholder: parsing existing ExportTx not yet supported on Flare P-chain
+  initBuilder(_tx: unknown): this {
+    super.initBuilder(_tx);
+    return this;
+  }
+
+  // Type verification not yet implemented for Flare P-chain
+  static verifyTxType(_baseTx: unknown): boolean {
+    return false;
+  }
+
+  verifyTxType(_baseTx: unknown): boolean {
+    return ExportTxBuilder.verifyTxType(_baseTx);
+  }
+
+  /**
+   * Create the internal transaction.
+   * @protected
+   */
+  // Build not implemented yet
+  protected buildFlareTransaction(): void {
+    throw new Error('Flare P-chain export transaction build not implemented');
+  }
+
+  /**
+   * Create the ExportedOut where the recipient address are the sender.
+   * Later a importTx should complete the operations signing with the same keys.
+   * @protected
+   */
+  protected exportedOutputs(): unknown[] {
+    return [];
+  }
+}