/*!
Math.uuid.js (v1.4)
http://www.broofa.com
mailto:robert@broofa.com
Copyright (c) 2010 Robert Kieffer
Dual licensed under the MIT and GPL licenses.
*/

/*
 * Generate a random uuid.
 *
 * USAGE: Math.uuid(length, radix)
 *   length - the desired number of characters
 *   radix  - the number of allowable values for each character.
 *
 * EXAMPLES:
 *   // No arguments  - returns RFC4122, version 4 ID
 *   >>> Math.uuid()
 *   "92329D39-6F5C-4520-ABFC-AAB64544E172"
 *
 *   // One argument - returns ID of the specified length
 *   >>> Math.uuid(15)     // 15 character ID (default base=62)
 *   "VcydxgltxrVZSTV"
 *
 *   // Two arguments - returns ID of the specified length, and radix. (Radix must be <= 62)
 *   >>> Math.uuid(8, 2)  // 8 character ID (base=2)
 *   "01001010"
 *   >>> Math.uuid(8, 10) // 8 character ID (base=10)
 *   "47473046"
 *   >>> Math.uuid(8, 16) // 8 character ID (base=16)
 *   "098F4D35"
 */
(function() {
  // Private array of chars to use
  var CHARS = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'.split('')

  Math.uuid = function(len, radix) {
    var chars = CHARS; var uuid = []; var i
    radix = radix || chars.length

    if (len) {
      // Compact form
      for (i = 0; i < len; i++) uuid[i] = chars[0 | Math.random() * radix]
    } else {
      // rfc4122, version 4 form
      var r

      // rfc4122 requires these characters
      uuid[8] = uuid[13] = uuid[18] = uuid[23] = '-'
      uuid[14] = '4'

      // Fill in random data.  At i==19 set the high bits of clock sequence as
      // per rfc4122, sec. 4.1.5
      for (i = 0; i < 36; i++) {
        if (!uuid[i]) {
          r = 0 | Math.random() * 16
          uuid[i] = chars[(i === 19) ? (r & 0x3) | 0x8 : r]
        }
      }
    }

    return uuid.join('')
  }

  // A more performant, but slightly bulkier, RFC4122v4 solution.  We boost performance
  // by minimizing calls to random()
  Math.uuidFast = function() {
    var chars = CHARS; var uuid = new Array(36); var rnd = 0; var r
    for (var i = 0; i < 36; i++) {
      if (i === 8 || i === 13 || i === 18 || i === 23) {
        uuid[i] = '-'
      } else if (i === 14) {
        uuid[i] = '4'
      } else {
        if (rnd <= 0x02) rnd = 0x2000000 + (Math.random() * 0x1000000) | 0
        r = rnd & 0xf
        rnd = rnd >> 4
        uuid[i] = chars[(i === 19) ? (r & 0x3) | 0x8 : r]
      }
    }
    return uuid.join('')
  }

  // A more compact, but less performant, RFC4122v4 solution:
  Math.uuidCompact = function() {
    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
      var r = Math.random() * 16 | 0; var v = c === 'x' ? r : (r & 0x3 | 0x8)
      return v.toString(16)
    })
  }
})()
