/**
 * @module spawn-posix
 * @author Toru Nagashima
 * @copyright 2015 Toru Nagashima. All rights reserved.
 * See LICENSE file in root directory for full license.
 */
'use strict'

// ------------------------------------------------------------------------------
// Requirements
// ------------------------------------------------------------------------------

const crossSpawn = require('cross-spawn')
const getDescendentProcessInfo = require('pidtree')

// ------------------------------------------------------------------------------
// Helpers
// ------------------------------------------------------------------------------

/**
 * Kills the new process and its sub processes.
 * @this ChildProcess
 * @returns {void}
 */
function kill () {
  getDescendentProcessInfo(this.pid, { root: true }, (err, pids) => {
    if (err) {
      return
    }

    for (const pid of pids) {
      try {
        process.kill(pid)
      } catch (_err) {
        // ignore.
      }
    }
  })
}

// ------------------------------------------------------------------------------
// Public Interface
// ------------------------------------------------------------------------------

/**
 * Launches a new process with the given command.
 * This is almost same as `child_process.spawn`.
 *
 * This returns a `ChildProcess` instance.
 * `kill` method of the instance kills the new process and its sub processes.
 *
 * @param {string} command - The command to run.
 * @param {string[]} args - List of string arguments.
 * @param {object} options - Options.
 * @returns {ChildProcess} A ChildProcess instance of new process.
 * @private
 */
module.exports = function spawn (command, args, options) {
  const child = crossSpawn(command, args, options)
  child.kill = kill

  return child
}
