const EventEmitter = require('events');
const axios = require('axios');
const xml2js = require('xml2js');

// 112-nu.nl per-service feeds + combined fallback
const FEED_URLS = [
  'https://112-nu.nl/hulpdiensten/rss',   // all services combined
  'https://112-nu.nl/brandweer/rss',
  'https://112-nu.nl/ambulance/rss',
  'https://112-nu.nl/politie/rss',
];

const COMBINED_FEED = FEED_URLS[0];
const POLL_INTERVAL_MS = 30_000;

// 112-nu.nl category codes → internal type
const CATEGORY_MAP = {
  BRA: 'fire', BRW: 'fire', BRAND: 'fire',
  AMB: 'ambulance', MKA: 'ambulance',
  POL: 'police', POLICE: 'police',
  KNRM: 'rescue', HELI: 'rescue', TRAUMA: 'rescue',
};

// Keyword fallback for when category is missing
const KEYWORD_MAP = [
  { type: 'fire',      words: ['brand', 'brandweer', 'uitslaande', 'bbrand', 'binnenbraand'] },
  { type: 'ambulance', words: ['ambulance', 'ambu', 'medisch', 'reanimatie', 'a1 ', 'a2 '] },
  { type: 'police',    words: ['politie', 'prio 1', 'prio 2', 'prio1', 'prio2'] },
  { type: 'rescue',    words: ['reddingsbrigade', 'knrm', 'grip', 'trauma', 'helikopter'] },
];

function detectType(category, title, description) {
  if (category) {
    const mapped = CATEGORY_MAP[category.toUpperCase().trim()];
    if (mapped) return mapped;
  }
  const lower = `${title} ${description}`.toLowerCase();
  for (const { type, words } of KEYWORD_MAP) {
    if (words.some(w => lower.includes(w))) return type;
  }
  return 'other';
}

function extractId(item) {
  const raw = item.guid?.[0];
  if (typeof raw === 'object') return raw._ ?? JSON.stringify(raw);
  return raw || item.link?.[0] || `${item.title?.[0]}|${item.pubDate?.[0]}`;
}

function extractLocation(link) {
  const m = link?.match(/\/melding\/\d+\/([^\/]+)\//);
  if (!m) return { display: null, slug: null };
  const slug = m[1];
  const display = slug.split('-').map(w => w.charAt(0).toUpperCase() + w.slice(1)).join(' ');
  return { display, slug };
}

function parseItems(rssData) {
  const items = rssData?.rss?.channel?.[0]?.item ?? [];
  return items.map(item => {
    const title       = item.title?.[0] ?? '';
    const description = item.description?.[0] ?? '';
    const category    = item.category?.[0] ?? '';
    const link        = item.link?.[0] ?? '';
    const { display: location, slug: locationSlug } = extractLocation(link);
    return {
      id:           extractId(item),
      title:        title.trim(),
      description:  description.trim(),
      pubDate:      item.pubDate?.[0] ?? new Date().toISOString(),
      link,
      type:         detectType(category, title, description),
      category:     category || null,
      location,
      locationSlug,
      image:        item.image?.[0] ?? null,
    };
  });
}

class P2000 extends EventEmitter {
  constructor() {
    super();
    this._seenIds = new Set();
    this._timer   = null;
    this._running = false;
  }

  async _fetchFeed() {
    try {
      const { data } = await axios.get(COMBINED_FEED, {
        timeout: 12_000,
        headers: { 'User-Agent': 'p2000-monitor/1.0' },
        responseType: 'text',
      });
      const parsed = await xml2js.parseStringPromise(data, { explicitArray: true, trim: true });
      return parseItems(parsed);
    } catch (err) {
      console.warn(`[p2000] Feed error: ${err.message}`);
      return [];
    }
  }

  async poll() {
    const messages = await this._fetchFeed();
    const isFirstRun = this._seenIds.size === 0;

    const fresh = messages.filter(m => !this._seenIds.has(m.id));
    for (const msg of fresh) this._seenIds.add(msg.id);

    if (isFirstRun) {
      this.emit('batch', messages.slice(0, 50));
      console.log(`[p2000] Initial batch: ${messages.length} messages`);
      return;
    }

    if (fresh.length) {
      console.log(`[p2000] ${fresh.length} new message(s)`);
    }

    // Emit oldest first so UI prepends in correct order
    for (const msg of fresh.reverse()) {
      this.emit('message', msg);
    }
  }

  start() {
    if (this._running) return;
    this._running = true;
    this.poll();
    this._timer = setInterval(() => this.poll(), POLL_INTERVAL_MS);
    console.log(`[p2000] Polling ${COMBINED_FEED} every ${POLL_INTERVAL_MS / 1000}s`);
  }

  stop() {
    if (this._timer) clearInterval(this._timer);
    this._running = false;
  }
}

module.exports = P2000;