/**
 * Consignment Reader Interface
 *
 * Defines the contract for locating and reading the RGB consignment file
 * produced by sendBegin(). The consignment is submitted to the gas-free
 * service for cryptographic verification before it co-signs the mining input.
 *
 * @module IConsignmentReader
 */

export interface IConsignmentReader {
  /**
   * Locate the consignment written by sendBegin() and return its contents as
   * a base64-encoded string.
   *
   * The path is derived deterministically:
   *   {walletDir}/transfers/{txid}/{assetId_without_rgb:_prefix}/consignment_out
   *
   * The TXID is stable for SegWit transactions — it does not change when
   * additional signatures (e.g. the service co-signature) are added — so it
   * can be computed from the *unsigned* PSBT returned by sendBegin().
   *
   * @param assetId    - The RGB asset ID (e.g. `rgb:abc123…`)
   * @param unsignedPsbt - The base64 PSBT string returned by sendBegin()
   * @returns Promise resolving to the base64-encoded consignment bytes
   * @throws {GasFreeError} with code PSBT_BUILD_FAILED if the PSBT cannot be
   *   parsed, if the wallet directory cannot be read, or if the file is absent
   */
  readForAsset(assetId: string, unsignedPsbt: string): Promise<string>;
}