/*
 * The puppet scrape backend: history pages over the validated core bridge.
 */

import type { FetchPage, ScrapeBackend } from "./engine.js";
import type { CoreMessage } from "./types.js";

/** The core `message.fetch` call the daemon injects. */
export type CoreFetch = (
    channelId: string,
    limit: number,
    options?: { before?: string; after?: string }
) => Promise<{ messages?: unknown[] }>;

export class PuppetBackend implements ScrapeBackend {
    readonly name = "puppet" as const;

    constructor(private readonly fetchMessages: CoreFetch) {}

    async fetchPage(channelId: string, before: string | null, limit: number): Promise<FetchPage> {
        const result = await this.fetchMessages(channelId, limit, before ? { before } : {});
        const messages = (result?.messages ?? []) as CoreMessage[];
        return { messages };
    }
}