// uuid.js // // Copyright © 2010-2012 Robert Kieffer // MIT License - opensource.org/licenses/mit-license.php

/*global window, require, define */ (function(_window) {

'use strict';

// Unique ID creation requires a high quality random # generator.  We feature
// detect to determine the best RNG source, normalizing to a function that
// returns 128-bits of randomness, since that's what's usually required
var _rng, _mathRNG, _nodeRNG, _whatwgRNG, _previousRoot;

function setupBrowser() {
  // Allow for MSIE11 msCrypto
  var _crypto = _window.crypto || _window.msCrypto;

  if (!_rng && _crypto && _crypto.getRandomValues) {
    // WHATWG crypto-based RNG - http://wiki.whatwg.org/wiki/Crypto
    //
    // Moderately fast, high quality
    try {
      var _rnds8 = new Uint8Array(16);
      _whatwgRNG = _rng = function whatwgRNG() {
        _crypto.getRandomValues(_rnds8);
        return _rnds8;
      };
      _rng();
    } catch(e) {}
  }

  if (!_rng) {
    // Math.random()-based (RNG)
    //
    // If all else fails, use Math.random().  It's fast, but is of unspecified
    // quality.
    var  _rnds = new Array(16);
    _mathRNG = _rng = function() {
      for (var i = 0, r; i < 16; i++) {
        if ((i & 0x03) === 0) { r = Math.random() * 0x100000000; }
        _rnds[i] = r >>> ((i & 0x03) << 3) & 0xff;
      }

      return _rnds;
    };
    if ('undefined' !== typeof console && console.warn) {
      console.warn("[SECURITY] node-uuid: crypto not usable, falling back to insecure Math.random()");
    }
  }
}

function setupNode() {
  // Node.js crypto-based RNG - http://nodejs.org/docs/v0.6.2/api/crypto.html
  //
  // Moderately fast, high quality
  if ('function' === typeof require) {
    try {
      var _rb = require('crypto').randomBytes;
      _nodeRNG = _rng = _rb && function() {return _rb(16);};
      _rng();
    } catch(e) {}
  }
}

if (_window) {
  setupBrowser();
} else {
  setupNode();
}

// Buffer class to use
var BufferClass = ('function' === typeof Buffer) ? Buffer : Array;

// Maps for number <-> hex string conversion
var _byteToHex = [];
var _hexToByte = {};
for (var i = 0; i < 256; i++) {
  _byteToHex[i] = (i + 0x100).toString(16).substr(1);
  _hexToByte[_byteToHex[i]] = i;
}

// **`parse()` - Parse a UUID into it's component bytes**
function parse(s, buf, offset) {
  var i = (buf && offset) || 0, ii = 0;

  buf = buf || [];
  s.toLowerCase().replace(/[0-9a-f]{2}/g, function(oct) {
    if (ii < 16) { // Don't overflow!
      buf[i + ii++] = _hexToByte[oct];
    }
  });

  // Zero out remaining bytes if string was short
  while (ii < 16) {
    buf[i + ii++] = 0;
  }

  return buf;
}

// **`unparse()` - Convert UUID byte array (ala parse()) into a string**
function unparse(buf, offset) {
  var i = offset || 0, bth = _byteToHex;
  return  bth[buf[i++]] + bth[buf[i++]] +
          bth[buf[i++]] + bth[buf[i++]] + '-' +
          bth[buf[i++]] + bth[buf[i++]] + '-' +
          bth[buf[i++]] + bth[buf[i++]] + '-' +
          bth[buf[i++]] + bth[buf[i++]] + '-' +
          bth[buf[i++]] + bth[buf[i++]] +
          bth[buf[i++]] + bth[buf[i++]] +
          bth[buf[i++]] + bth[buf[i++]];
}

// **`v1()` - Generate time-based UUID**
//
// Inspired by https://github.com/LiosK/UUID.js
// and http://docs.python.org/library/uuid.html

// random #'s we need to init node and clockseq
var _seedBytes = _rng();

// Per 4.5, create and 48-bit node id, (47 random bits + multicast bit = 1)
var _nodeId = [
  _seedBytes[0] | 0x01,
  _seedBytes[1], _seedBytes[2], _seedBytes[3], _seedBytes[4], _seedBytes[5]
];

// Per 4.2.2, randomize (14 bit) clockseq
var _clockseq = (_seedBytes[6] << 8 | _seedBytes[7]) & 0x3fff;

// Previous uuid creation time
var _lastMSecs = 0, _lastNSecs = 0;

// See https://github.com/broofa/node-uuid for API details
function v1(options, buf, offset) {
  var i = buf && offset || 0;
  var b = buf || [];

  options = options || {};

  var clockseq = (options.clockseq != null) ? options.clockseq : _clockseq;

  // UUID timestamps are 100 nano-second units since the Gregorian epoch,
  // (1582-10-15 00:00).  JSNumbers aren't precise enough for this, so
  // time is handled internally as 'msecs' (integer milliseconds) and 'nsecs'
  // (100-nanoseconds offset from msecs) since unix epoch, 1970-01-01 00:00.
  var msecs = (options.msecs != null) ? options.msecs : new Date().getTime();

  // Per 4.2.1.2, use count of uuid's generated during the current clock
  // cycle to simulate higher resolution clock
  var nsecs = (options.nsecs != null) ? options.nsecs : _lastNSecs + 1;

  // Time since last uuid creation (in msecs)
  var dt = (msecs - _lastMSecs) + (nsecs - _lastNSecs)/10000;

  // Per 4.2.1.2, Bump clockseq on clock regression
  if (dt < 0 && options.clockseq == null) {
    clockseq = clockseq + 1 & 0x3fff;
  }

  // Reset nsecs if clock regresses (new clockseq) or we've moved onto a new
  // time interval
  if ((dt < 0 || msecs > _lastMSecs) && options.nsecs == null) {
    nsecs = 0;
  }

  // Per 4.2.1.2 Throw error if too many uuids are requested
  if (nsecs >= 10000) {
    throw new Error('uuid.v1(): Can\'t create more than 10M uuids/sec');
  }

  _lastMSecs = msecs;
  _lastNSecs = nsecs;
  _clockseq = clockseq;

  // Per 4.1.4 - Convert from unix epoch to Gregorian epoch
  msecs += 12219292800000;

  // `time_low`
  var tl = ((msecs & 0xfffffff) * 10000 + nsecs) % 0x100000000;
  b[i++] = tl >>> 24 & 0xff;
  b[i++] = tl >>> 16 & 0xff;
  b[i++] = tl >>> 8 & 0xff;
  b[i++] = tl & 0xff;

  // `time_mid`
  var tmh = (msecs / 0x100000000 * 10000) & 0xfffffff;
  b[i++] = tmh >>> 8 & 0xff;
  b[i++] = tmh & 0xff;

  // `time_high_and_version`
  b[i++] = tmh >>> 24 & 0xf | 0x10; // include version
  b[i++] = tmh >>> 16 & 0xff;

  // `clock_seq_hi_and_reserved` (Per 4.2.2 - include variant)
  b[i++] = clockseq >>> 8 | 0x80;

  // `clock_seq_low`
  b[i++] = clockseq & 0xff;

  // `node`
  var node = options.node || _nodeId;
  for (var n = 0; n < 6; n++) {
    b[i + n] = node[n];
  }

  return buf ? buf : unparse(b);
}

// **`v4()` - Generate random UUID**

// See https://github.com/broofa/node-uuid for API details
function v4(options, buf, offset) {
  // Deprecated - 'format' argument, as supported in v1.2
  var i = buf && offset || 0;

  if (typeof(options) === 'string') {
    buf = (options === 'binary') ? new BufferClass(16) : null;
    options = null;
  }
  options = options || {};

  var rnds = options.random || (options.rng || _rng)();

  // Per 4.4, set bits for version and `clock_seq_hi_and_reserved`
  rnds[6] = (rnds[6] & 0x0f) | 0x40;
  rnds[8] = (rnds[8] & 0x3f) | 0x80;

  // Copy bytes to buffer, if provided
  if (buf) {
    for (var ii = 0; ii < 16; ii++) {
      buf[i + ii] = rnds[ii];
    }
  }

  return buf || unparse(rnds);
}

// Export public API
var uuid = v4;
uuid.v1 = v1;
uuid.v4 = v4;
uuid.parse = parse;
uuid.unparse = unparse;
uuid.BufferClass = BufferClass;
uuid._rng = _rng;
uuid._mathRNG = _mathRNG;
uuid._nodeRNG = _nodeRNG;
uuid._whatwgRNG = _whatwgRNG;

if (('undefined' !== typeof module) && module.exports) {
  // Publish as node.js module
  module.exports = uuid;
} else if (typeof define === 'function' && define.amd) {
  // Publish as AMD module
  define(function() {return uuid;});

} else {
  // Publish as global (in browsers)
  _previousRoot = _window.uuid;

  // **`noConflict()` - (browser only) to reset global 'uuid' var**
  uuid.noConflict = function() {
    _window.uuid = _previousRoot;
    return uuid;
  };

  _window.uuid = uuid;
}

})('undefined' !== typeof window ? window : null);