// SPDX-FileCopyrightText: © 2026 LEDGER SAS
// SPDX-License-Identifier: Apache-2.0

import type { xdr } from '@stellar/stellar-sdk'
import { Networks, Transaction as StellarSdkTransaction } from '@stellar/stellar-sdk'

export function combine(
  transaction: string | xdr.TransactionEnvelope,
  signature: string[],
  publicKey: string
): string {
  if (signature.length !== 1) {
    throw new Error(`Stellar combine expects exactly one signature, got ${signature.length}`)
  }
  const unsignedTx = new StellarSdkTransaction(transaction, Networks.PUBLIC)
  unsignedTx.addSignature(publicKey, signature[0])
  return unsignedTx.toXDR()
}