import { type Address, type Hex } from "viem";
import type { Metadata } from "../types";
/**
 * Adds metadata to a transaction object by concatenating additional
 * hex-encoded data to the transaction's `data` field. The additional
 * data may include a timestamp and an origin identifier derived
 * from the metadata.
 *
 * The function ensures that the transaction data is correctly formatted
 * and includes optional metadata elements if provided.
 *
 * @param {Object} tx - The original transaction object.
 * @param {Hex} tx.data - The existing hex-encoded data for the transaction.
 * @param {bigint} tx.value - The value to be sent with the transaction.
 * @param {Address} tx.to - The recipient address of the transaction.
 * @param {Metadata} metadata - An object containing optional metadata fields
 * such as `timestamp` and `origin`.
 *
 * @returns {Object} - A new transaction object with the modified `data` field
 * including the concatenated metadata.
 *
 * If no `data` is present in the original transaction, the function returns
 * the transaction unmodified.
 */
export declare function addTransactionMetadata(tx: {
    data: Hex;
    value: bigint;
    to: Address;
}, metadata: Metadata): {
    data: Hex;
    value: bigint;
    to: Address;
};