feat(sdk-coin-flrp): enhance transaction builders and utils with new methods

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

@@ -35,7 +35,7 @@ import {
   FLARE_ATOMIC_PARSED_PREFIX,
   HEX_ENCODING,
 } from './constants';
-import { createFlexibleHexRegex } from './utils';
+import utils, { createFlexibleHexRegex } from './utils';
 
 /**
  * Flare P-chain atomic transaction builder with FlareJS credential support.
@@ -420,4 +420,58 @@ export abstract class AtomicTransactionBuilder {
       );
     }
   }
+
+  /**
+   * Threshold is an int that names the number of unique signatures required to spend the output.
+   * Must be less than or equal to the length of Addresses.
+   * @param {number}
+   */
+  threshold(value: number): this {
+    this.validateThreshold(value);
+    this.transaction._threshold = value;
+    return this;
+  }
+
+  /**
+   * Validates the threshold
+   * @param threshold
+   */
+  validateThreshold(threshold: number): void {
+    if (!threshold || threshold !== 2) {
+      throw new BuildTransactionError('Invalid transaction: threshold must be set to 2');
+    }
+  }
+
+  /**
+   * fromPubKey is a list of unique addresses that correspond to the private keys that can be used to spend this output.
+   * @param {string | string[]} senderPubKey
+   */
+  // TODO: check the format of the public keys
+  fromPubKey(senderPubKey: string | string[]): this {
+    const pubKeys = senderPubKey instanceof Array ? senderPubKey : [senderPubKey];
+    this.transaction._fromAddresses = pubKeys.map(utils.parseAddress);
+    return this;
+  }
+
+  /**
+   * Locktime is a long that contains the unix timestamp that this output can be spent after.
+   * The unix timestamp is specific to the second.
+   * @param value
+   */
+  locktime(value: number): this {
+    const locktime = BigInt(value);
+    this.validateLocktime(locktime);
+    this.transaction._locktime = locktime;
+    return this;
+  }
+
+  /**
+   * Validates locktime
+   * @param locktime
+   */
+  validateLocktime(locktime: bigint): void {
+    if (!locktime || locktime < 0n) {
+      throw new BuildTransactionError('Invalid transaction: locktime must be 0 or higher');
+    }
+  }
 }

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

@@ -15,6 +15,7 @@ import {
   NETWORK_ID_PROP,
   BLOCKCHAIN_ID_PROP,
 } from './constants';
+import utils from './utils';
 
 // Lightweight interface placeholders replacing Avalanche SDK transaction shapes
 interface FlareExportInputShape {
@@ -95,8 +96,12 @@ export class ExportInCTxBuilder extends AtomicInCTransactionBuilder {
    * @param pAddresses
    */
   to(pAddresses: string | string[]): this {
-    const pubKeys = Array.isArray(pAddresses) ? pAddresses : pAddresses.split('~');
-    // For now ensure they are stored as bech32 / string addresses directly
+    const pubKeys = pAddresses instanceof Array ? pAddresses : pAddresses.split('~');
+    if (!utils.isValidAddress(pubKeys)) {
+      throw new BuildTransactionError('Invalid to address');
+    }
+
+    // TODO need to check if address should be string or Buffer
     this.transaction._to = pubKeys.map((a) => a.toString());
     return this;
   }

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

@@ -5,6 +5,7 @@ export { KeyPair } from './keyPair';
 export { Utils };
 export { TransactionBuilderFactory } from './transactionBuilderFactory';
 export { Transaction } from './transaction';
+export { TransactionBuilder } from './transactionBuilder';
 export { AtomicTransactionBuilder } from './atomicTransactionBuilder';
 export { AtomicInCTransactionBuilder } from './atomicInCTransactionBuilder';
 export { ImportInCTxBuilder } from './importInCTxBuilder';

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

@@ -124,7 +124,7 @@ export class KeyPair extends Secp256k1ExtendedKeyPair {
    *
    * @returns {Buffer} The address buffer derived from the public key
    */
-  private getAddressBuffer(): Buffer {
+  getAddressBuffer(): Buffer {
     try {
       // Use the safe buffer method for address derivation
       return this.getAddressSafeBuffer();