/**
 * A Series of utility functions
 */
const fs = require('fs'),
    si = require('systeminformation');

function noOp() {}
let sysdataPath = './res/data/sys.json';
let sysData = {};

/**
 * returns the extension of a file for the given filename.
 * @param  {String} filename The name of the file.
 * @return {String}          A string that represents the file-extension.
 */
exports.getExtension = function (filename) {
    if (!filename) return null;
    try {
        let exts = filename.match(/\.[a-z]+/g); // get the extension by using regex
        if (exts) return exts[exts.length - 1]; // return the found extension
        else return null; // return null if no extension could be found
    } catch (error) {
        console.error(error);
        return null;
    }
};

exports.genSystemData = function () {
    si.currentLoad(data => {
        if (!sysData["100perc"]) sysData["100perc"] = [];
        sysData["100perc"].push([sysData["100perc"].length, data.currentload]);
        if (sysData["100perc"].length > 100) {
            sysData["100perc"].shift();
            for (let i = 0; i < sysData["100perc"].length; i++) {
                sysData["100perc"][i][0] -=1;
            }
        }
    });
    fs.writeFile(sysdataPath, JSON.stringify(sysData), err => {
        if (err) console.error(err);
    });
};

/**
 * lets you define a cleanup for your program exit
 * @param       {Function} callback the cleanup function
 * @constructor
 * @author CanyonCasa & Pier-Luc Gendreau on StackOverflow
 */
exports.Cleanup = function Cleanup(callback) {

  // attach user callback to the process event emitter
  // if no callback, it will still exit gracefully on Ctrl-C
  callback = callback || noOp;
  process.on('cleanup',callback);

  // do app specific cleaning before exiting
  process.on('exit', function () {
    process.emit('cleanup');
  });

  // catch ctrl+c event and exit normally
  process.on('SIGINT', function () {
    console.log('Ctrl-C...');
    process.exit(2);
  });

  //catch uncaught exceptions, trace, then exit normally
  process.on('uncaughtException', function(e) {
    console.log('Uncaught Exception...');
    console.log(e.stack);
    process.exit(99);
  });
};