/**
 * Copyright 2013-2017  Zaid Abdulla
 *
 * This file is part of GenieACS.
 *
 * GenieACS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * GenieACS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with GenieACS.  If not, see <http://www.gnu.org/licenses/>.
 */
"use strict";

const childProcess = require("child_process");
const crypto = require ("crypto");

const config = require("./config");

const TIMEOUT = config.get('EXT_TIMEOUT');

const processes = {};
const jobs = {};

function messageHandler(message) {
  let func = jobs[message[0]];
  if (func) {
    delete jobs[message[0]];
    func(null, message[1], message[2]);
  }
}


function run(args, callback) {
  let scriptName = args[0];

  if (!processes[scriptName]) {
    let p = childProcess.fork('lib/extension-wrapper', [scriptName]);

    p.on('error', function() {
      kill(processes[scriptName]);
      delete processes[scriptName];
    });

    p.on('disconnect', function() {
      kill(processes[scriptName]);
      delete processes[scriptName];
    });

    p.on('message', messageHandler);
    processes[scriptName] = p;
  }

  let id = crypto.randomBytes(8).toString('hex');
  jobs[id] = callback;
  setTimeout(function() {
    if (id in jobs) {
      delete jobs[id];
      return callback(null, {code: "timeout", message: "Extension timed out"});
    }
  }, TIMEOUT);

  return processes[scriptName].send([id, args.slice(1)]);
};


function kill(process) {
  if (process.signalCode !== null || process.exitCode !== null)
    return;

  let timeToKill = Date.now() + 5000;

  process.kill();

  let t = setInterval(function() {
    if (process.signalCode !== null || process.exitCode !== null) {
      clearInterval(t);
    }
    else if (Date.now() > timeToKill) {
      process.kill('SIGKILL');
      clearInterval(t);
    }
  }, 100);
}


function killAll() {
  for (let n in processes)
    kill(processes[n]);
}


exports.run = run;
exports.killAll = killAll;