<?php

/**
 * File: uuid.inc
 * Author: Andrew Moore (http://php.net/manual/en/function.uniqid.php#94959)
 * Integrated by: Matt Shuter
 * Purpose: Generates VALID RFC 4211 COMPLIANT Universally Unique IDentifiers (UUID) version 3, 4 and 5.
 * Version 3 and 5 UUIDs are named based. They require a namespace (another valid UUID) and a value (the name).
 * Given the same namespace and name, the output is always the same.
 * Version 4 UUIDs are pseudo-random.
 * UUIDs generated below validates using OSSP UUID Tool, and output for named-based UUIDs are exactly the same.
 * Created: Feb 20, 2017
 *
 * Copyright 2017: Cyber Perspective, LLC, All rights reserved
 * Released under the Apache v2.0 License
 *
 * See license.txt for details
 *
 * Change Log:
 *  - Oct 16, 2017 - File created
 */
/* Usage
 *
 * Named-based UUID.
 * $v3uuid = UUID::v3('1546058f-5a25-4334-85ae-e68f2a44bbaf', 'SomeRandomString');
 * $v5uuid = UUID::v5('1546058f-5a25-4334-85ae-e68f2a44bbaf', 'SomeRandomString');
 *
 * Pseudo-random UUID
 * $v4uuid = UUID::v4();
 */

class UUID {

  public static function v3($namespace, $name) {
    if (!self::is_valid($namespace))
      return false;

    // Get hexadecimal components of namespace
    $nhex = str_replace(array('-', '{', '}'), '', $namespace);

    // Binary Value
    $nstr = '';

    // Convert Namespace UUID to bits
    for ($i = 0; $i < strlen($nhex); $i += 2) {
      $nstr .= chr(hexdec($nhex[$i] . $nhex[$i + 1]));
    }

    // Calculate hash value
    $hash = md5($nstr . $name);

    return sprintf('%08s-%04s-%04x-%04x-%12s',
        // 32 bits for "time_low"
        substr($hash, 0, 8),
        // 16 bits for "time_mid"
        substr($hash, 8, 4),
        // 16 bits for "time_hi_and_version",
        // four most significant bits holds version number 3
        (hexdec(substr($hash, 12, 4)) & 0x0fff) | 0x3000,
        // 16 bits, 8 bits for "clk_seq_hi_res",
        // 8 bits for "clk_seq_low",
        // two most significant bits holds zero and one for variant DCE1.1
        (hexdec(substr($hash, 16, 4)) & 0x3fff) | 0x8000,
        // 48 bits for "node"
        substr($hash, 20, 12)
    );
  }

  public static function v4() {
    return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
        // 32 bits for "time_low"
        mt_rand(0, 0xffff), mt_rand(0, 0xffff),
        // 16 bits for "time_mid"
        mt_rand(0, 0xffff),
        // 16 bits for "time_hi_and_version",
        // four most significant bits holds version number 4
        mt_rand(0, 0x0fff) | 0x4000,
        // 16 bits, 8 bits for "clk_seq_hi_res",
        // 8 bits for "clk_seq_low",
        // two most significant bits holds zero and one for variant DCE1.1
        mt_rand(0, 0x3fff) | 0x8000,
        // 48 bits for "node"
        mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
    );
  }

  public static function v5($namespace, $name) {
    if (!self::is_valid($namespace))
      return false;

    // Get hexadecimal components of namespace
    $nhex = str_replace(array('-', '{', '}'), '', $namespace);

    // Binary Value
    $nstr = '';

    // Convert Namespace UUID to bits
    for ($i = 0; $i < strlen($nhex); $i += 2) {
      $nstr .= chr(hexdec($nhex[$i] . $nhex[$i + 1]));
    }

    // Calculate hash value
    $hash = sha1($nstr . $name);

    return sprintf('%08s-%04s-%04x-%04x-%12s',
        // 32 bits for "time_low"
        substr($hash, 0, 8),
        // 16 bits for "time_mid"
        substr($hash, 8, 4),
        // 16 bits for "time_hi_and_version",
        // four most significant bits holds version number 5
        (hexdec(substr($hash, 12, 4)) & 0x0fff) | 0x5000,
        // 16 bits, 8 bits for "clk_seq_hi_res",
        // 8 bits for "clk_seq_low",
        // two most significant bits holds zero and one for variant DCE1.1
        (hexdec(substr($hash, 16, 4)) & 0x3fff) | 0x8000,
        // 48 bits for "node"
        substr($hash, 20, 12)
    );
  }

  public static function is_valid($uuid) {
    return preg_match('/^\{?[0-9a-f]{8}\-?[0-9a-f]{4}\-?[0-9a-f]{4}\-?' .
            '[0-9a-f]{4}\-?[0-9a-f]{12}\}?$/i', $uuid) === 1;
  }

}
