/**
 * analytics.js
 * This is a sample function to interact with Google Analytics.
 * 
 * Description: 
 *  Displays active users on a website
 * 
 * Commands:
 *  hubot users - displays the websites active users
 *
 * @license MIT
 * @version 0.14
 * @author  Steffan Brown, https://github.com/skbrown333/hubot-analytics
 * @updated 2018-02-16
*/

const GAPI = require('gapitoken');
const GA = require('googleanalytics');

const serviceEmail = process.env.HUBOT_GOOGLE_SERVICE_EMAIL;
const keyFilePath = process.env.HUBOT_GOOGLE_KEY_PATH;
const HUBOT_SITE_NAME = process.env.HUBOT_SITE_NAME;
const HUBOT_GOOGLE_ANALYTICS_ID = process.env.HUBOT_GOOGLE_ANALYTICS_ID;

module.exports = function(robot) {
    robot.respond(/users/, getAnalytics);
};

function getAnalytics (res) {
    const gapi = new GAPI({
        iss: serviceEmail,
        scope: 'https://www.googleapis.com/auth/analytics.readonly',
        keyFile: keyFilePath,
    }, function(err) {
        
        gapi.getToken(function(err, token) { 
            let util = require('util');
            let config = {
                'token': token,
            };
            let ga = new GA.GA(config);

            
            const metrics = [
                'rt:activeUsers',
            ];

            const options = {
                'ids': `ga:${ HUBOT_GOOGLE_ANALYTICS_ID }`,
                'metrics': metrics.join(','),
            };


            ga.get(options, function(err, entries) {
                if(!entries || !entries[0]) {
                    res.reply(`${ HUBOT_SITE_NAME } currently has 0 active users`);
                    return;
                }
                res.reply(`${ HUBOT_SITE_NAME } currently has ${entries[0].metrics[0]['rt:activeUsers']} active users`);
            });

        });     
    });
}