/**
 * Copyright 2013-2015, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 */

/**
 * Usage note:
 * This module makes a best effort to export the same data we would internally.
 * At Facebook we use a server-generated module that does the parsing and
 * exports the data for the client to use. We can't rely on a server-side
 * implementation in open source so instead we make use of an open source
 * library to do the heavy lifting and then make some adjustments as necessary.
 * It's likely there will be some differences. Some we can smooth over.
 * Others are going to be harder.
 */

'use strict';

var UAParser = require('ua-parser-js');

var UNKNOWN = 'Unknown';

var PLATFORM_MAP = {
  'Mac OS': 'Mac OS X'
};

/**
 * Convert from UAParser platform name to what we expect.
 */
function convertPlatformName(name) {
  return PLATFORM_MAP[name] || name;
}

/**
 * Get the version number in parts. This is very naive. We actually get major
 * version as a part of UAParser already, which is generally good enough, but
 * let's get the minor just in case.
 */
function getBrowserVersion(version) {
  if (!version) {
    return {
      major: '',
      minor: ''
    };
  }
  var parts = version.split('.');
  return {
    major: parts[0],
    minor: parts[1]
  };
}

/**
 * Get the UA data fom UAParser and then convert it to the format we're
 * expecting for our APIS.
 */
var parser = new UAParser();
var results = parser.getResult();

// Do some conversion first.
var browserVersionData = getBrowserVersion(results.browser.version);
var uaData = {
  browserArchitecture: results.cpu.architecture || UNKNOWN,
  browserFullVersion: results.browser.version || UNKNOWN,
  browserMinorVersion: browserVersionData.minor || UNKNOWN,
  browserName: results.browser.name || UNKNOWN,
  browserVersion: results.browser.major || UNKNOWN,
  deviceName: results.device.model || UNKNOWN,
  engineName: results.engine.name || UNKNOWN,
  engineVersion: results.engine.version || UNKNOWN,
  platformArchitecture: results.cpu.architecture || UNKNOWN,
  platformName: convertPlatformName(results.os.name) || UNKNOWN,
  platformVersion: results.os.version || UNKNOWN,
  platformFullVersion: results.os.version || UNKNOWN
};

module.exports = uaData;