import { RssParser } from '../rss';
import type { Logger, NormalizedStory } from '../../shared/types';

/**
 * PR-wire RSS poller (FREE-DATA-STACK §1.4 / P1.2 Tier 3) — press releases
 * that the other free feeds miss, mostly small-caps.
 *
 * Ticker extraction relies on the wire convention of exchange tags in the
 * text: "(NYSE: ABC)", "(Nasdaq: XYZ)". Stories without an exchange tag
 * produce no tickers and are dropped by the pipeline's universe filter —
 * that's intentional; untagged wire stories are rarely decision-grade.
 *
 * Feed list is overridable: NEWS_PRWIRE_FEEDS="url1,url2" in .env
 * (wire RSS URLs change occasionally — if a feed 404s, update the env var).
 */
export class PrWirePoller {
  private static readonly DEFAULT_FEEDS = [
    // GlobeNewswire — public-company news
    'https://www.globenewswire.com/RssFeed/orgclass/1/feedTitle/GlobeNewswire%20-%20News%20about%20Public%20Companies',
    // PR Newswire — all news releases
    'https://www.prnewswire.com/rss/news-releases-list.rss',
  ];

  private static readonly EXCHANGE_TAG =
    /\((?:NYSE(?:\s+American)?|NASDAQ|Nasdaq|AMEX|CBOE|OTC(?:QB|QX|MKTS)?)\s*:\s*([A-Za-z][A-Za-z.]{0,5})\)/g;

  private readonly feeds: string[];

  constructor(
    private readonly logger: Logger,
    feeds?: string[],
  ) {
    const env = process.env.NEWS_PRWIRE_FEEDS;
    this.feeds = feeds ?? (env ? env.split(',').map((s) => s.trim()) : PrWirePoller.DEFAULT_FEEDS);
  }

  async poll(): Promise<NormalizedStory[]> {
    const stories: NormalizedStory[] = [];
    for (const feed of this.feeds) {
      try {
        const xml = await this.fetchText(feed);
        stories.push(...PrWirePoller.parseFeed(xml));
      } catch (err) {
        this.logger.warn(`PR-wire feed failed (${feed}):`, (err as Error).message);
      }
    }
    return stories;
  }

  /** Parse one RSS feed. Public static for fixture tests. */
  static parseFeed(xml: string): NormalizedStory[] {
    const stories: NormalizedStory[] = [];
    for (const item of RssParser.blocks(xml, 'item')) {
      const title = RssParser.tag(item, 'title');
      const url = RssParser.link(item);
      const pubDate = RssParser.tag(item, 'pubDate');
      if (!title || !url) continue;

      const description = RssParser.tag(item, 'description') ?? '';
      const tickers = PrWirePoller.extractTickers(`${title} ${description}`);
      if (tickers.length === 0) continue; // no exchange tag → skip early

      stories.push({
        tickers,
        headline: title,
        body: description || null,
        source: 'prwire',
        url,
        publishedAt: pubDate ? new Date(pubDate).toISOString() : new Date().toISOString(),
      });
    }
    return stories;
  }

  /** "(NYSE: ABC)" / "(Nasdaq: XYZ)" → ['ABC', 'XYZ']. Public for tests. */
  static extractTickers(text: string): string[] {
    const out = new Set<string>();
    for (const m of text.matchAll(PrWirePoller.EXCHANGE_TAG)) {
      out.add(m[1].toUpperCase());
    }
    return [...out];
  }

  private async fetchText(url: string): Promise<string> {
    const res = await fetch(url, {
      headers: { 'User-Agent': 'market-screener/1.0 (+rss reader)' },
    });
    if (!res.ok) throw new Error(`HTTP ${res.status}`);
    return res.text();
  }
}