// Shared RSS fetch used by both the "news" (curated) and "feeds" (personal)
// source modules — same fetch/parse/sort/slice over a list of feed URLs.

import Parser from "rss-parser";
import type { NewsConfig, NewsPayload } from "@/lib/schemas/sources/news";

const parser = new Parser();

function hostname(url: string): string {
  try {
    return new URL(url).hostname.replace(/^www\./, "");
  } catch {
    return url;
  }
}

export async function fetchRss(
  config: NewsConfig,
  signal?: AbortSignal,
): Promise<NewsPayload> {
  const results = await Promise.allSettled(
    config.feeds.map(async (url) => {
      // Fetch ourselves so the AbortSignal/timeout is honored, then parse text.
      const res = await fetch(url, {
        signal,
        headers: { "User-Agent": "PersonalDashboard/0.1" },
      });
      if (!res.ok) throw new Error(`${hostname(url)} ${res.status}`);
      const xml = await res.text();
      const feed = await parser.parseString(xml);
      const source = feed.title || hostname(url);
      return (feed.items ?? []).map((it) => ({
        title: (it.title ?? "Untitled").trim(),
        link: it.link ?? "",
        source,
        isoDate: it.isoDate ?? null,
      }));
    }),
  );

  const items = results
    .filter((r): r is PromiseFulfilledResult<NewsPayload["items"]> => r.status === "fulfilled")
    .flatMap((r) => r.value)
    .filter((it) => it.link)
    .sort((a, b) => {
      const ta = a.isoDate ? Date.parse(a.isoDate) : 0;
      const tb = b.isoDate ? Date.parse(b.isoDate) : 0;
      return tb - ta;
    })
    .slice(0, config.limit);

  if (items.length === 0) {
    const firstErr = results.find((r) => r.status === "rejected") as
      | PromiseRejectedResult
      | undefined;
    if (firstErr) throw new Error(String(firstErr.reason?.message ?? firstErr.reason));
  }

  return { items };
}