import { Client, simpleFetchHandler } from "@atcute/client";
import { resolvePdsEndpoint } from "../identity.ts";

// `com.atproto.repo.listRecords` is a public, unauthenticated query, so the
// backfill crawler talks to each PDS with a bare fetch handler — no OAuth session,
// no app password. `fetchImpl` is an injection seam for tests (a canned fetch).
export function makePdsClient(
	endpoint: string,
	fetchImpl?: typeof fetch,
): Client {
	return new Client({
		handler: simpleFetchHandler({
			service: endpoint,
			...(fetchImpl ? { fetch: fetchImpl } : {}),
		}),
	});
}

export interface ResolvedPdsClient {
	client: Client;
	endpoint: string;
}

// Resolve a DID's PDS endpoint and build an unauthenticated client for it.
// Returns null when the DID document can't be resolved or exposes no PDS.
export async function resolvePdsClient(
	did: string,
): Promise<ResolvedPdsClient | null> {
	const endpoint = await resolvePdsEndpoint(did);
	if (!endpoint) return null;
	return { client: makePdsClient(endpoint), endpoint };
}