import type { StorefrontAPIClient, CachedType, Log } from '@scayle/storefront-core';
/**
 * Fetches the key of the first active campaign.
 *
 * Retrieves campaigns from the Storefront API, filters for non-ended campaigns,
 * sorts them, and returns the key of the first active one.
 * The retrieved campaigns are cached for a specified duration.
 *
 * @see https://scayle.dev/en/core-documentation/checkout-guide/features/promotions/discounts-and-offers/price-campaigns
 * @see https://scayle.dev/en/api-guides/storefront-api/resources/campaigns/list-campaigns
 *
 * @param sapiClient The Storefront API client.
 * @param cached The caching function.
 * @param log The logging instance.
 *
 * @throws {Error} If fetching or processing campaigns fails.
 *
 * @returns The key of the first active campaign, or undefined if no active campaign is found or an error occurs.
 */
export declare const fetchCampaignKey: (sapiClient: StorefrontAPIClient, cached: CachedType, log: Log) => Promise<string | undefined>;