feat(sdk-coin-flrp): enhance transaction builders with addressesIndex handling

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

@@ -6,6 +6,7 @@ import {
   UnsignedTx,
   Credential,
   TransferableInput,
+  TransferInput,
   TransferOutput,
   Address,
   utils as FlareUtils,
@@ -186,16 +187,17 @@ export class ImportInCTxBuilder extends AtomicInCTransactionBuilder {
     return importedInputs.map((input) => {
       const txid = input.utxoID.toString();
       const outputidx = input.utxoID.outputIdx.toString();
+      const transferInput = input.input as TransferInput;
+      const addressesIndex = transferInput.sigIndicies();
 
       return {
         outputID: SECP256K1_Transfer_Output,
         amount: input.amount().toString(),
         txid: utils.cb58Encode(Buffer.from(txid, 'hex')),
         outputidx: outputidx,
-        threshold: this.transaction._threshold,
-        addresses: this.transaction._fromAddresses.map((addr) =>
-          utils.addressToString(this.transaction._network.hrp, this.transaction._network.alias, Buffer.from(addr))
-        ),
+        threshold: addressesIndex.length || this.transaction._threshold,
+        addresses: [],
+        addressesIndex,
       };
     });
   }

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

@@ -198,15 +198,16 @@ export class ImportInPTxBuilder extends AtomicTransactionBuilder {
     return importedInputs.map((input) => {
       const utxoId = input.utxoID;
       const transferInput = input.input as TransferInput;
+      const addressesIndex = transferInput.sigIndicies();
+
       const utxo: DecodedUtxoObj = {
         outputID: SECP256K1_Transfer_Output,
         amount: transferInput.amount().toString(),
         txid: utils.cb58Encode(Buffer.from(utxoId.txID.toBytes())),
         outputidx: utxoId.outputIdx.value().toString(),
-        threshold: this.transaction._threshold,
-        addresses: this.transaction._fromAddresses.map((addr) =>
-          utils.addressToString(this.transaction._network.hrp, this.transaction._network.alias, Buffer.from(addr))
-        ),
+        threshold: addressesIndex.length || this.transaction._threshold,
+        addresses: [],
+        addressesIndex,
       };
       return utxo;
     });

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

@@ -113,6 +113,17 @@ export abstract class AtomicTransactionBuilder extends TransactionBuilder {
     const sender = (this.transaction as Transaction)._fromAddresses;
     const hasAddresses = sender && sender.length >= threshold;
 
+    // If we have pre-computed addressesIndex (from parsing a transaction), use it directly
+    // This is the authoritative source for signature ordering from parsed transactions
+    if (utxo.addressesIndex && utxo.addressesIndex.length >= threshold) {
+      // Create credentials matching the sigIndicies order from the parsed transaction
+      const emptySignatures: ReturnType<typeof utils.createNewSig>[] = [];
+      for (let i = 0; i < threshold; i++) {
+        emptySignatures.push(utils.createNewSig(''));
+      }
+      return new Credential(emptySignatures);
+    }
+
     if (!hasAddresses || !utxo.addresses || utxo.addresses.length === 0) {
       // Fallback: use all zeros if no addresses available
       const emptySignatures: ReturnType<typeof utils.createNewSig>[] = [];
@@ -163,6 +174,21 @@ export abstract class AtomicTransactionBuilder extends TransactionBuilder {
     const addressMap = new FlareUtils.AddressMap();
     const sender = (this.transaction as Transaction)._fromAddresses;
 
+    // If we have pre-computed addressesIndex (from parsing a transaction), use it directly
+    // addressesIndex from sigIndicies() tells us: addressesIndex[slotIdx] = utxoAddressIdx
+    // This means slot 'slotIdx' expects signature from UTXO address at index 'utxoAddressIdx'
+    // Assuming sender[i] corresponds to utxoAddress[i], we map sender[addressesIndex[slotIdx]] to slotIdx
+    if (utxo.addressesIndex && utxo.addressesIndex.length >= threshold && sender && sender.length >= threshold) {
+      for (let slotIdx = 0; slotIdx < threshold; slotIdx++) {
+        const utxoAddrIdx = utxo.addressesIndex[slotIdx];
+        // Map the sender that corresponds to this UTXO address index to this slot
+        if (utxoAddrIdx < sender.length) {
+          addressMap.set(new Address(sender[utxoAddrIdx]), slotIdx);
+        }
+      }
+      return addressMap;
+    }
+
     // If UTXO has addresses, compute addressesIndex to determine signature order
     if (utxo && utxo.addresses && utxo.addresses.length > 0 && sender && sender.length >= threshold) {
       const utxoAddresses = utxo.addresses.map((a) => utils.parseAddress(a));