import { clean, fetchHtml, slugify } from "./http";
import type { ScrapedJob, Scraper } from "./types";

// Optius publishes an official RSS feed with region/field filters, so no HTML scraping is needed.
// Build a feed URL at https://www.optius.com/rss/ (its IDs differ from the search page's IDs).

const tag = (xml: string, name: string) => new RegExp(`<${name}[^>]*>([\\s\\S]*?)</${name}>`).exec(xml)?.[1];
const text = (s: string | undefined) => clean((s ?? "").replace(/^<!\[CDATA\[([\s\S]*)\]\]>$/, "$1"));

export function parseOptiusFeed(xml: string): ScrapedJob[] {
  return [...xml.matchAll(/<item>([\s\S]*?)<\/item>/g)]
    .map((m): ScrapedJob | null => {
      const item = m[1]!;
      const url = text(tag(item, "link") ?? tag(item, "guid"));
      const id = /-(\d+)-\1\/?$/.exec(url)?.[1] ?? /-(\d+)\/?$/.exec(url)?.[1];
      const title = text(tag(item, "title"));
      if (!id || !title) return null;
      const pubDate = tag(item, "pubDate");
      return {
        externalId: id,
        title,
        url,
        company: text(tag(item, "employer")) || undefined,
        tags: [...item.matchAll(/<field(?:\s[^>]*)?>([\s\S]*?)<\/field>/g)].map((f) => text(f[1])).filter(Boolean),
        postedAt: pubDate ? new Date(pubDate).toISOString() : undefined,
      };
    })
    .filter((j): j is ScrapedJob => j !== null);
}

/** Scraper for an optius.com RSS feed, e.g. "https://www.optius.com/rss/?regija=7&podrocje=7". */
export function optius(label: string, feedUrl: string): Scraper {
  return {
    id: `optius-${label.normalize("NFD").replace(/[̀-ͯ]/g, "").replace(/[^A-Za-z0-9]+/g, "-").replace(/^-|-$/g, "").toLowerCase()}`,
    name: `Optius (${label})`,
    async scrape() {
      const xml = await fetchHtml(feedUrl);
      if (!xml.includes("<rss")) throw new Error("response is not an RSS feed (site changed?)");
      return parseOptiusFeed(xml);
    },
  };
}