#!/usr/bin/env node
'use strict';

// Not using ES6 in that file since we want it to "launch" on older nodes.
/* eslint-disable prefer-arrow-callback, prefer-template */
/* eslint-env es6:false */
var sysPath = require('path');
var join = sysPath.join;
var fs = require('fs');
var childProcessFork = require('child_process').fork;

var version = process.versions.node;
if (parseInt(version) < 4) {
  console.error(
    'Error: Brunch 2+ requires Node.js v4 or higher (you have v' + version + ') ' +
    'Upgrade Node.js or use older Brunch (not recommended): npm i -g brunch@1'
  );
  process.exit(1);
}

global[Symbol.for('start-time')] = Date.now();

var files = {old: 'cli.js', new: 'run-cli.js'};
var runSeparateWatchProcess = function(cliPath) {
  process.env.BRUNCH_FORKED_PROCESS = 'true';
  var args = process.env.BRUNCH_DEVTOOLS ? ['--inspect', '--debug-brk'] : process.execArgv;
  var proc = childProcessFork(cliPath, process.argv.slice(2), {execArgv: args});
  proc.on('message', function(message) {
    if (message === 'reload') {
      proc.kill();
      runSeparateWatchProcess(cliPath);
    }
  });

  process.on('SIGTERM', function() {
    proc.kill();
  });
};

var loadBrunch = function(libPath) {
  var cmd = process.argv[2];
  var runCli = join(libPath, files.new);

  // This approach is only needed for watch command.
  if ((cmd === 'w' || cmd === 'watch') && fs.existsSync(runCli)) {
    try {
      runSeparateWatchProcess(runCli);
      return;
    } catch (e) {
      // empty
    }
  }

  // This is needed to support cases when the local Brunch is of an older version
  // and does not have a run-cli.js file.
  require(join(libPath, files.old)).run();
};

var loadGlobalBrunch = function() {
  loadBrunch(join(fs.realpathSync(__dirname), '..', 'lib'));
};

var localPath = join(sysPath.resolve('.'), 'node_modules', 'brunch', 'lib', files.old);
if (fs.existsSync(localPath)) {
  try {
    loadBrunch(sysPath.dirname(localPath));
  } catch (error) {
    console.error(
      'Brunch: Local install exists, but failed to load it. ' +
      'Continuing with global install:', error
    );
    loadGlobalBrunch();
  }
} else {
  loadGlobalBrunch();
}