/**
 * DuckDuckGo search-provider adapter.
 *
 * Used as the keyless default so `clai` works out of the box without
 * any API key (Requirement 3.5). The adapter targets DuckDuckGo's
 * lite-HTML endpoint at `https://html.duckduckgo.com/html/?q=…`,
 * parses the response with `cheerio`, unwraps the in-page redirect
 * shim (`/l/?uddg=<encoded>`) so callers see the destination URL, and
 * applies the same URL filter `web.search` enforces (Requirement 7.3)
 * before forwarding hits to the registry handler.
 *
 * The adapter does not need redirect-chain capture, fine-grained
 * timing, TLS metadata, or DNS-rebinding protection beyond the
 * per-invocation `AbortSignal`, so it deliberately bypasses the full
 * `fetch-core` pipeline. A small `node:https.request`-based helper
 * keeps the implementation simple while still honoring the 15-second
 * `web.search` invocation timeout (Requirement 1.8) via the supplied
 * `AbortSignal`.
 *
 * Per Requirement 6.7 the adapter issues exactly one outbound request
 * per invocation and never retries on transient failure.
 */
import https from "node:https";
import type { SearchProvider } from "./provider.js";
/**
 * Inject point for the underlying HTTPS transport. Mirrors the seam in
 * `./brave.ts` so unit tests can drive the adapter without touching the
 * network. Production code never invokes the setter.
 */
type HttpsRequestFn = typeof https.request;
/**
 * Test-only seam: swap the HTTPS transport used by the adapter. Tests use
 * this to inject a stubbed `request` implementation that emits scripted
 * responses; production callers never invoke it.
 */
export declare function __setDuckduckgoHttpsRequestForTesting(fn: HttpsRequestFn | undefined): void;
/**
 * The DuckDuckGo {@link SearchProvider} adapter.
 *
 * Resolves a search query into a {@link RawProviderResponse} carrying
 * up to `maxResults` `{title, url, snippet}` hits. URL filtering and
 * `maxResults` truncation happen here so the registry handler does not
 * have to re-walk the cheerio tree; the handler still re-applies the
 * filter for defense in depth (Requirement 7.3).
 */
export declare const duckduckgoProvider: SearchProvider;
export {};