const http = require('http');
const https = require('https');

const requestJson = (url, { timeoutMs = 2000 } = {}) => {
  return new Promise((resolve, reject) => {
    const u = new URL(url);
    const lib = u.protocol === 'https:' ? https : http;

    const req = lib.request(
      {
        protocol: u.protocol,
        hostname: u.hostname,
        port: u.port,
        path: `${u.pathname}${u.search}`,
        method: 'GET'
      },
      (res) => {
        let raw = '';
        res.setEncoding('utf8');
        res.on('data', (chunk) => (raw += chunk));
        res.on('end', () => {
          if (res.statusCode && (res.statusCode < 200 || res.statusCode >= 300)) {
            return reject(new Error(`SRS HTTP API status ${res.statusCode}`));
          }

          try {
            resolve(JSON.parse(raw || '{}'));
          } catch (e) {
            reject(new Error('Invalid JSON from SRS HTTP API'));
          }
        });
      }
    );

    req.on('error', reject);
    req.setTimeout(timeoutMs, () => {
      req.destroy(new Error('SRS HTTP API request timeout'));
    });
    req.end();
  });
};

const normalizeStreamName = (s) => {
  if (!s) return null;
  if (typeof s === 'string') return s;
  return s.stream || s.name || s.id || null;
};

const isPublishActive = (streamObj) => {
  const publish = streamObj && streamObj.publish;
  if (!publish) return false;
  if (typeof publish.active === 'boolean') return publish.active;
  return Boolean(publish.cid);
};

let warnedOnce = false;

const getActiveStreamKeys = async ({ app = 'live' } = {}) => {
  const host = process.env.SRS_HOST || 'localhost';
  const apiPort = process.env.SRS_API_PORT || 1985;

  const url = `http://${host}:${apiPort}/api/v1/streams/?count=100`;

  try {
    const payload = await requestJson(url, { timeoutMs: 1500 });
    const streams = payload.streams || payload.data?.streams || [];

    const active = new Set();
    for (const s of streams) {
      if (app && s.app && s.app !== app) continue;
      if (!isPublishActive(s)) continue;
      const name = normalizeStreamName(s);
      if (name) active.add(name);
    }

    return active;
  } catch (e) {
    if (!warnedOnce) {
      warnedOnce = true;
      console.warn(`[SRS] HTTP API unavailable at ${url}`);
      console.warn(`[SRS] Error: ${e.message}`);
      console.warn(`[SRS] Will fallback to callbacks/in-memory status.`);
    }
    return new Set();
  }
};

module.exports = {
  getActiveStreamKeys
};