<?php



/**

 * Class RandomStringGenerator

 * @package Utils

 *

 * Solution taken from here:

 * http://stackoverflow.com/a/13733588/1056679

 */

class RandomStringGenerator

{

	/** @var string */

	protected $alphabet;



	/** @var int */

	protected $alphabetLength;





	/**

	 * @param string $alphabet

	 */

	public function __construct($alphabet = '')

	{

		if ('' !== $alphabet) {

			$this->setAlphabet($alphabet);

		} else {

			$this->setAlphabet(

				implode(range('a', 'z'))

				. implode(range('A', 'Z'))

				. implode(range(0, 9))

			);

		}

	}



	/**

	 * @param string $alphabet

	 */

	public function setAlphabet($alphabet)

	{

		$this->alphabet = $alphabet;

		$this->alphabetLength = strlen($alphabet);

	}



	/**

	 * @param int $length

	 * @return string

	 */

	public function generate($length)

	{

		$token = '';



		for ($i = 0; $i < $length; $i++) {

			$randomKey = $this->getRandomInteger(0, $this->alphabetLength);

			$token .= $this->alphabet[$randomKey];

		}



		return $token;

	}



	/**

	 * @param int $min

	 * @param int $max

	 * @return int

	 */

	protected function getRandomInteger($min, $max)

	{

		$range = ($max - $min);



		if ($range < 0) {

			// Not so random...

			return $min;

		}



		$log = log($range, 2);



		// Length in bytes.

		$bytes = (int) ($log / 8) + 1;



		// Length in bits.

		$bits = (int) $log + 1;



		// Set all lower bits to 1.

		$filter = (int) (1 << $bits) - 1;



		do {

			$rnd = hexdec(bin2hex(openssl_random_pseudo_bytes($bytes)));



			// Discard irrelevant bits.

			$rnd = $rnd & $filter;



		} while ($rnd >= $range);



		return ($min + $rnd);

	}



	function generateSplit4($length) {

		$continuous = $this->generate($length);

		$parts = chunk_split($continuous, 4, '-');

		if ($parts[strlen($parts)-1] == '-') {

			$parts = substr($parts, 0, strlen($parts) - 1);

		}

		return $parts;

	}



	static function likeYouTube() {

		$gen = new self();

		return $gen->generate(10);

	}



	/**

	 * http://www.anyexample.com/programming/php/php__password_generation.xml

	 * @param int $syllables

	 * @return string

	 */

	public function generateReadablePassword($syllables = 3) {

		$use_prefix = false;

		// Define function unless it is already exists

		if (!function_exists('ae_arr')) {

			// This function returns random array element

			function ae_arr(&$arr) {

				return $arr[rand(0, sizeof($arr)-1)];

			}

		}



		// 20 prefixes

		$prefix = array('aero', 'anti', 'auto', 'bi', 'bio',

			'cine', 'deca', 'demo', 'dyna', 'eco',

			'ergo', 'geo', 'gyno', 'hypo', 'kilo',

			'mega', 'tera', 'mini', 'nano', 'duo');



		// 10 random suffixes

		$suffix = array('dom', 'ity', 'ment', 'sion', 'ness',

			'ence', 'er', 'ist', 'tion', 'or');



		// 8 vowel sounds

		$vowels = array('a', 'o', 'e', 'i', 'y', 'u', 'ou', 'oo');



		// 20 random consonants

		$consonants = array('w', 'r', 't', 'p', 's', 'd', 'f', 'g', 'h', 'j',

			'k', 'l', 'z', 'x', 'c', 'v', 'b', 'n', 'm', 'qu');



		$password = $use_prefix?ae_arr($prefix):'';

		$password_suffix = ae_arr($suffix);



		for($i=0; $i<$syllables; $i++)

		{

			// selecting random consonant

			$doubles = array('n', 'm', 't', 's');

			$c = ae_arr($consonants);

			if (in_array($c, $doubles)&&($i!=0)) { // maybe double it

				if (rand(0, 2) == 1) // 33% probability

					$c .= $c;

			}

			$password .= $c;

			//



			// selecting random vowel

			$password .= ae_arr($vowels);



			if ($i == $syllables - 1) // if suffix begin with vovel

				if (in_array($password_suffix[0], $vowels)) // add one more consonant

					$password .= ae_arr($consonants);



		}



		// selecting random suffix

		$password .= $password_suffix;



		return $password;

	}



}