var crypto = require('crypto');

function generateSecurePathHash(expires, client_ip, secret) {
    if (!expires || !client_ip || !secret) throw new Error('Must provide all token components');

    var input = expires + client_ip + ' ' + secret;
    var binaryHash = crypto.createHash('md5').update(input).digest();
    var base64Value = new Buffer(binaryHash).toString('base64');
    return base64Value.replace(/=/g, '').replace(/\+/g, '-').replace(/\//g, '_');
}

function getStreamUrl(ip, secret) {
    const expiresTimestamp = new Date(Date.now() + (1000 * 60 * 30)).getTime();
    const expires = String(Math.round(expiresTimestamp / 1000));
    
    const token = generateSecurePathHash(expires, ip, secret);

    return `https://example.com/video/hls/${token}/${expires}/live.m3u8`;
}

getStreamUrl('127.0.0.1', 'uigfp(@#tfpIUDGPFiouGDF');
// https://example.com/video/hls/LdS-kcC-JGVHGNTFlX-6Sw/1526373776/live.m3u8