Validation.php

<?php
/**
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the LICENSE.txt
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @since         1.2.0
 * @license       http://www.opensource.org/licenses/mit-license.php MIT License
 */
namespace Cake\Validation;

use Cake\Utility\String;
use LogicException;
use RuntimeException;

/**
 * Validation Class. Used for validation of model data
 *
 * Offers different validation methods.
 *
 */
class Validation
{

    /**
     * Some complex patterns needed in multiple places
     *
     * @var array
     */
    protected static $_pattern = [
        'hostname' => '(?:[_\p{L}0-9][-_\p{L}0-9]*\.)*(?:[\p{L}0-9][-\p{L}0-9]{0,62})\.(?:(?:[a-z]{2}\.)?[a-z]{2,})'
    ];

    /**
     * Holds an array of errors messages set in this class.
     * These are used for debugging purposes
     *
     * @var array
     */
    public static $errors = [];

    /**
     * Checks that a string contains something other than whitespace
     *
     * Returns true if string contains something other than whitespace
     *
     * $check can be passed as an array:
     * array('check' => 'valueToCheck');
     *
     * @param string|array $check Value to check
     * @return bool Success
     */
    public static function notEmpty($check)
    {
        if (is_array($check)) {
            extract(static::_defaults($check));
        }

        if (empty($check) && $check != '0') {
            return false;
        }
        return static::_check($check, '/[^\s]+/m');
    }

    /**
     * Checks that a string contains only integer or letters
     *
     * Returns true if string contains only integer or letters
     *
     * $check can be passed as an array:
     * array('check' => 'valueToCheck');
     *
     * @param string|array $check Value to check
     * @return bool Success
     */
    public static function alphaNumeric($check)
    {
        if (is_array($check)) {
            extract(static::_defaults($check));
        }

        if (empty($check) && $check != '0') {
            return false;
        }
        return self::_check($check, '/^[\p{Ll}\p{Lm}\p{Lo}\p{Lt}\p{Lu}\p{Nd}]+$/Du');
    }

    /**
     * Checks that a string length is within specified range.
     * Spaces are included in the character count.
     * Returns true if string matches value min, max, or between min and max,
     *
     * @param string $check Value to check for length
     * @param int $min Minimum value in range (inclusive)
     * @param int $max Maximum value in range (inclusive)
     * @return bool Success
     */
    public static function lengthBetween($check, $min, $max)
    {
        $length = mb_strlen($check);
        return ($length >= $min && $length <= $max);
    }

    /**
     * Returns true if field is left blank -OR- only whitespace characters are present in its value
     * Whitespace characters include Space, Tab, Carriage Return, Newline
     *
     * $check can be passed as an array:
     * array('check' => 'valueToCheck');
     *
     * @param string|array $check Value to check
     * @return bool Success
     */
    public static function blank($check)
    {
        if (is_array($check)) {
            extract(static::_defaults($check));
        }
        return !static::_check($check, '/[^\\s]/');
    }

    /**
     * Validation of credit card numbers.
     * Returns true if $check is in the proper credit card format.
     *
     * @param string|array $check credit card number to validate
     * @param string|array $type 'all' may be passed as a string, defaults to fast which checks format of most major credit cards
     *    if an array is used only the values of the array are checked.
     *    Example: array('amex', 'bankcard', 'maestro')
     * @param bool $deep set to true this will check the Luhn algorithm of the credit card.
     * @param string|null $regex A custom regex can also be passed, this will be used instead of the defined regex values
     * @return bool Success
     * @see Validation::luhn()
     */
    public static function cc($check, $type = 'fast', $deep = false, $regex = null)
    {
        if (is_array($check)) {
            extract(static::_defaults($check));
        }

        $check = str_replace(['-', ' '], '', $check);
        if (mb_strlen($check) < 13) {
            return false;
        }

        if ($regex !== null) {
            if (static::_check($check, $regex)) {
                return static::luhn($check, $deep);
            }
        }
        $cards = [
            'all' => [
                'amex' => '/^3[4|7]\\d{13}$/',
                'bankcard' => '/^56(10\\d\\d|022[1-5])\\d{10}$/',
                'diners' => '/^(?:3(0[0-5]|[68]\\d)\\d{11})|(?:5[1-5]\\d{14})$/',
                'disc' => '/^(?:6011|650\\d)\\d{12}$/',
                'electron' => '/^(?:417500|4917\\d{2}|4913\\d{2})\\d{10}$/',
                'enroute' => '/^2(?:014|149)\\d{11}$/',
                'jcb' => '/^(3\\d{4}|2100|1800)\\d{11}$/',
                'maestro' => '/^(?:5020|6\\d{3})\\d{12}$/',
                'mc' => '/^5[1-5]\\d{14}$/',
                'solo' => '/^(6334[5-9][0-9]|6767[0-9]{2})\\d{10}(\\d{2,3})?$/',
                'switch' => '/^(?:49(03(0[2-9]|3[5-9])|11(0[1-2]|7[4-9]|8[1-2])|36[0-9]{2})\\d{10}(\\d{2,3})?)|(?:564182\\d{10}(\\d{2,3})?)|(6(3(33[0-4][0-9])|759[0-9]{2})\\d{10}(\\d{2,3})?)$/',
                'visa' => '/^4\\d{12}(\\d{3})?$/',
                'voyager' => '/^8699[0-9]{11}$/'
            ],
            'fast' => '/^(?:4[0-9]{12}(?:[0-9]{3})?|5[1-5][0-9]{14}|6011[0-9]{12}|3(?:0[0-5]|[68][0-9])[0-9]{11}|3[47][0-9]{13})$/'
        ];

        if (is_array($type)) {
            foreach ($type as $value) {
                $regex = $cards['all'][strtolower($value)];

                if (static::_check($check, $regex)) {
                    return static::luhn($check, $deep);
                }
            }
        } elseif ($type === 'all') {
            foreach ($cards['all'] as $value) {
                $regex = $value;

                if (static::_check($check, $regex)) {
                    return static::luhn($check, $deep);
                }
            }
        } else {
            $regex = $cards['fast'];

            if (static::_check($check, $regex)) {
                return static::luhn($check, $deep);
            }
        }
        return false;
    }

    /**
     * Used to compare 2 numeric values.
     *
     * @param string|array $check1 if string is passed for, a string must also be passed for $check2
     *    used as an array it must be passed as array('check1' => value, 'operator' => 'value', 'check2' -> value)
     * @param string $operator Can be either a word or operand
     *    is greater >, is less <, greater or equal >=
     *    less or equal <=, is less <, equal to ==, not equal !=
     * @param int $check2 only needed if $check1 is a string
     * @return bool Success
     */
    public static function comparison($check1, $operator = null, $check2 = null)
    {
        if (is_array($check1)) {
            extract($check1, EXTR_OVERWRITE);
        }
        $operator = str_replace([' ', "\t", "\n", "\r", "\0", "\x0B"], '', strtolower($operator));

        switch ($operator) {
            case 'isgreater':
            case '>':
                if ($check1 > $check2) {
                    return true;
                }
                break;
            case 'isless':
            case '<':
                if ($check1 < $check2) {
                    return true;
                }
                break;
            case 'greaterorequal':
            case '>=':
                if ($check1 >= $check2) {
                    return true;
                }
                break;
            case 'lessorequal':
            case '<=':
                if ($check1 <= $check2) {
                    return true;
                }
                break;
            case 'equalto':
            case '==':
                if ($check1 == $check2) {
                    return true;
                }
                break;
            case 'notequal':
            case '!=':
                if ($check1 != $check2) {
                    return true;
                }
                break;
            default:
                static::$errors[] = 'You must define the $operator parameter for Validation::comparison()';
        }
        return false;
    }

    /**
     * Used when a custom regular expression is needed.
     *
     * @param string|array $check When used as a string, $regex must also be a valid regular expression.
     *    As and array: array('check' => value, 'regex' => 'valid regular expression')
     * @param string|null $regex If $check is passed as a string, $regex must also be set to valid regular expression
     * @return bool Success
     */
    public static function custom($check, $regex = null)
    {
        if (is_array($check)) {
            extract(static::_defaults($check));
        }
        if ($regex === null) {
            static::$errors[] = 'You must define a regular expression for Validation::custom()';
            return false;
        }
        return static::_check($check, $regex);
    }

    /**
     * Date validation, determines if the string passed is a valid date.
     * keys that expect full month, day and year will validate leap years.
     *
     * Years are valid from 1800 to 2999.
     *
     * ### Formats:
     *
     * - `dmy` 27-12-2006 or 27-12-06 separators can be a space, period, dash, forward slash
     * - `mdy` 12-27-2006 or 12-27-06 separators can be a space, period, dash, forward slash
     * - `ymd` 2006-12-27 or 06-12-27 separators can be a space, period, dash, forward slash
     * - `dMy` 27 December 2006 or 27 Dec 2006
     * - `Mdy` December 27, 2006 or Dec 27, 2006 comma is optional
     * - `My` December 2006 or Dec 2006
     * - `my` 12/2006 or 12/06 separators can be a space, period, dash, forward slash
     * - `ym` 2006/12 or 06/12 separators can be a space, period, dash, forward slash
     * - `y` 2006 just the year without any separators
     *
     * @param string|\DateTime $check a valid date string/object
     * @param string|array $format Use a string or an array of the keys above.
     *    Arrays should be passed as array('dmy', 'mdy', etc)
     * @param string|null $regex If a custom regular expression is used this is the only validation that will occur.
     * @return bool Success
     */
    public static function date($check, $format = 'ymd', $regex = null)
    {
        if ($check instanceof \DateTime) {
            return true;
        }
        if ($regex !== null) {
            return static::_check($check, $regex);
        }
        $month = '(0[123456789]|10|11|12)';
        $separator = '([- /.])';
        $fourDigitYear = '(([1][8-9][0-9][0-9])|([2][0-9][0-9][0-9]))';
        $twoDigitYear = '([0-9]{2})';
        $year = '(?:' . $fourDigitYear . '|' . $twoDigitYear . ')';

        $regex['dmy'] = '%^(?:(?:31(\\/|-|\\.|\\x20)(?:0?[13578]|1[02]))\\1|(?:(?:29|30)' .
            $separator . '(?:0?[1,3-9]|1[0-2])\\2))(?:(?:1[6-9]|[2-9]\\d)?\\d{2})$|^(?:29' .
            $separator . '0?2\\3(?:(?:(?:1[6-9]|[2-9]\\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))$|^(?:0?[1-9]|1\\d|2[0-8])' .
            $separator . '(?:(?:0?[1-9])|(?:1[0-2]))\\4(?:(?:1[6-9]|[2-9]\\d)?\\d{2})$%';

        $regex['mdy'] = '%^(?:(?:(?:0?[13578]|1[02])(\\/|-|\\.|\\x20)31)\\1|(?:(?:0?[13-9]|1[0-2])' .
            $separator . '(?:29|30)\\2))(?:(?:1[6-9]|[2-9]\\d)?\\d{2})$|^(?:0?2' . $separator . '29\\3(?:(?:(?:1[6-9]|[2-9]\\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))$|^(?:(?:0?[1-9])|(?:1[0-2]))' .
            $separator . '(?:0?[1-9]|1\\d|2[0-8])\\4(?:(?:1[6-9]|[2-9]\\d)?\\d{2})$%';

        $regex['ymd'] = '%^(?:(?:(?:(?:(?:1[6-9]|[2-9]\\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00)))' .
            $separator . '(?:0?2\\1(?:29)))|(?:(?:(?:1[6-9]|[2-9]\\d)?\\d{2})' .
            $separator . '(?:(?:(?:0?[13578]|1[02])\\2(?:31))|(?:(?:0?[1,3-9]|1[0-2])\\2(29|30))|(?:(?:0?[1-9])|(?:1[0-2]))\\2(?:0?[1-9]|1\\d|2[0-8]))))$%';

        $regex['dMy'] = '/^((31(?!\\ (Feb(ruary)?|Apr(il)?|June?|(Sep(?=\\b|t)t?|Nov)(ember)?)))|((30|29)(?!\\ Feb(ruary)?))|(29(?=\\ Feb(ruary)?\\ (((1[6-9]|[2-9]\\d)(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00)))))|(0?[1-9])|1\\d|2[0-8])\\ (Jan(uary)?|Feb(ruary)?|Ma(r(ch)?|y)|Apr(il)?|Ju((ly?)|(ne?))|Aug(ust)?|Oct(ober)?|(Sep(?=\\b|t)t?|Nov|Dec)(ember)?)\\ ((1[6-9]|[2-9]\\d)\\d{2})$/';

        $regex['Mdy'] = '/^(?:(((Jan(uary)?|Ma(r(ch)?|y)|Jul(y)?|Aug(ust)?|Oct(ober)?|Dec(ember)?)\\ 31)|((Jan(uary)?|Ma(r(ch)?|y)|Apr(il)?|Ju((ly?)|(ne?))|Aug(ust)?|Oct(ober)?|(Sep)(tember)?|(Nov|Dec)(ember)?)\\ (0?[1-9]|([12]\\d)|30))|(Feb(ruary)?\\ (0?[1-9]|1\\d|2[0-8]|(29(?=,?\\ ((1[6-9]|[2-9]\\d)(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00)))))))\\,?\\ ((1[6-9]|[2-9]\\d)\\d{2}))$/';

        $regex['My'] = '%^(Jan(uary)?|Feb(ruary)?|Ma(r(ch)?|y)|Apr(il)?|Ju((ly?)|(ne?))|Aug(ust)?|Oct(ober)?|(Sep(?=\\b|t)t?|Nov|Dec)(ember)?)' .
            $separator . '((1[6-9]|[2-9]\\d)\\d{2})$%';

        $regex['my'] = '%^(' . $month . $separator . $year . ')$%';
        $regex['ym'] = '%^(' . $year . $separator . $month . ')$%';
        $regex['y'] = '%^(' . $fourDigitYear . ')$%';

        $format = (is_array($format)) ? array_values($format) : [$format];
        foreach ($format as $key) {
            if (static::_check($check, $regex[$key]) === true) {
                return true;
            }
        }
        return false;
    }

    /**
     * Validates a datetime value
     *
     * All values matching the "date" core validation rule, and the "time" one will be valid
     *
     * @param string|\DateTime $check Value to check
     * @param string|array $dateFormat Format of the date part. See Validation::date for more information.
     * @param string|null $regex Regex for the date part. If a custom regular expression is used this is the only validation that will occur.
     * @return bool True if the value is valid, false otherwise
     * @see Validation::date
     * @see Validation::time
     */
    public static function datetime($check, $dateFormat = 'ymd', $regex = null)
    {
        if ($check instanceof \DateTime) {
            return true;
        }
        $valid = false;
        $parts = explode(' ', $check);
        if (!empty($parts) && count($parts) > 1) {
            $time = array_pop($parts);
            $date = implode(' ', $parts);
            $valid = static::date($date, $dateFormat, $regex) && static::time($time);
        }
        return $valid;
    }

    /**
     * Time validation, determines if the string passed is a valid time.
     * Validates time as 24hr (HH:MM) or am/pm ([H]H:MM[a|p]m)
     * Does not allow/validate seconds.
     *
     * @param string|\DateTime $check a valid time string/object
     * @return bool Success
     */
    public static function time($check)
    {
        if ($check instanceof \DateTime) {
            return true;
        }
        return static::_check($check, '%^((0?[1-9]|1[012])(:[0-5]\d){0,2} ?([AP]M|[ap]m))$|^([01]\d|2[0-3])(:[0-5]\d){0,2}$%');
    }

    /**
     * Boolean validation, determines if value passed is a boolean integer or true/false.
     *
     * @param string $check a valid boolean
     * @return bool Success
     */
    public static function boolean($check)
    {
        $booleanList = [0, 1, '0', '1', true, false];
        return in_array($check, $booleanList, true);
    }

    /**
     * Checks that a value is a valid decimal. Both the sign and exponent are optional.
     *
     * Valid Places:
     *
     * - null => Any number of decimal places, including none. The '.' is not required.
     * - true => Any number of decimal places greater than 0, or a float|double. The '.' is required.
     * - 1..N => Exactly that many number of decimal places. The '.' is required.
     *
     * @param float $check The value the test for decimal.
     * @param int $places Decimal places.
     * @param string|null $regex If a custom regular expression is used, this is the only validation that will occur.
     * @return bool Success
     */
    public static function decimal($check, $places = null, $regex = null)
    {
        if ($regex === null) {
            $lnum = '[0-9]+';
            $dnum = "[0-9]*[\.]{$lnum}";
            $sign = '[+-]?';
            $exp = "(?:[eE]{$sign}{$lnum})?";

            if ($places === null) {
                $regex = "/^{$sign}(?:{$lnum}|{$dnum}){$exp}$/";

            } elseif ($places === true) {
                if (is_float($check) && floor($check) === $check) {
                    $check = sprintf("%.1f", $check);
                }
                $regex = "/^{$sign}{$dnum}{$exp}$/";

            } elseif (is_numeric($places)) {
                $places = '[0-9]{' . $places . '}';
                $dnum = "(?:[0-9]*[\.]{$places}|{$lnum}[\.]{$places})";
                $regex = "/^{$sign}{$dnum}{$exp}$/";
            }
        }

        // account for localized floats.
        $data = localeconv();
        $check = str_replace($data['thousands_sep'], '', $check);
        $check = str_replace($data['decimal_point'], '.', $check);

        return static::_check($check, $regex);
    }

    /**
     * Validates for an email address.
     *
     * Only uses getmxrr() checking for deep validation, or
     * any PHP version on a non-windows distribution
     *
     * @param string $check Value to check
     * @param bool $deep Perform a deeper validation (if true), by also checking availability of host
     * @param string $regex Regex to use (if none it will use built in regex)
     * @return bool Success
     */
    public static function email($check, $deep = false, $regex = null)
    {
        if (is_array($check)) {
            extract(static::_defaults($check));
        }

        if ($regex === null) {
            $regex = '/^[\p{L}0-9!#$%&\'*+\/=?^_`{|}~-]+(?:\.[\p{L}0-9!#$%&\'*+\/=?^_`{|}~-]+)*@' . self::$_pattern['hostname'] . '$/ui';
        }
        $return = static::_check($check, $regex);
        if ($deep === false || $deep === null) {
            return $return;
        }

        if ($return === true && preg_match('/@(' . static::$_pattern['hostname'] . ')$/i', $check, $regs)) {
            if (function_exists('getmxrr') && getmxrr($regs[1], $mxhosts)) {
                return true;
            }
            if (function_exists('checkdnsrr') && checkdnsrr($regs[1], 'MX')) {
                return true;
            }
            return is_array(gethostbynamel($regs[1]));
        }
        return false;
    }

    /**
     * Checks that value is exactly $comparedTo.
     *
     * @param mixed $check Value to check
     * @param mixed $comparedTo Value to compare
     * @return bool Success
     */
    public static function equalTo($check, $comparedTo)
    {
        return ($check === $comparedTo);
    }

    /**
     * Checks that value has a valid file extension.
     *
     * @param string|array $check Value to check
     * @param array $extensions file extensions to allow. By default extensions are 'gif', 'jpeg', 'png', 'jpg'
     * @return bool Success
     */
    public static function extension($check, $extensions = ['gif', 'jpeg', 'png', 'jpg'])
    {
        if (is_array($check)) {
            return static::extension(array_shift($check), $extensions);
        }
        $extension = strtolower(pathinfo($check, PATHINFO_EXTENSION));
        foreach ($extensions as $value) {
            if ($extension === strtolower($value)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Validation of an IP address.
     *
     * @param string $check The string to test.
     * @param string $type The IP Protocol version to validate against
     * @return bool Success
     */
    public static function ip($check, $type = 'both')
    {
        $type = strtolower($type);
        $flags = 0;
        if ($type === 'ipv4') {
            $flags = FILTER_FLAG_IPV4;
        }
        if ($type === 'ipv6') {
            $flags = FILTER_FLAG_IPV6;
        }
        return (bool)filter_var($check, FILTER_VALIDATE_IP, ['flags' => $flags]);
    }

    /**
     * Checks whether the length of a string is greater or equal to a minimal length.
     *
     * @param string $check The string to test
     * @param int $min The minimal string length
     * @return bool Success
     */
    public static function minLength($check, $min)
    {
        return mb_strlen($check) >= $min;
    }

    /**
     * Checks whether the length of a string is smaller or equal to a maximal length..
     *
     * @param string $check The string to test
     * @param int $max The maximal string length
     * @return bool Success
     */
    public static function maxLength($check, $max)
    {
        return mb_strlen($check) <= $max;
    }

    /**
     * Checks that a value is a monetary amount.
     *
     * @param string $check Value to check
     * @param string $symbolPosition Where symbol is located (left/right)
     * @return bool Success
     */
    public static function money($check, $symbolPosition = 'left')
    {
        $money = '(?!0,?\d)(?:\d{1,3}(?:([, .])\d{3})?(?:\1\d{3})*|(?:\d+))((?!\1)[,.]\d{1,2})?';
        if ($symbolPosition === 'right') {
            $regex = '/^' . $money . '(?<!\x{00a2})\p{Sc}?$/u';
        } else {
            $regex = '/^(?!\x{00a2})\p{Sc}?' . $money . '$/u';
        }
        return static::_check($check, $regex);
    }

    /**
     * Validates a multiple select. Comparison is case sensitive by default.
     *
     * Valid Options
     *
     * - in => provide a list of choices that selections must be made from
     * - max => maximum number of non-zero choices that can be made
     * - min => minimum number of non-zero choices that can be made
     *
     * @param array $check Value to check
     * @param array $options Options for the check.
     * @param bool $caseInsensitive Set to true for case insensitive comparison.
     * @return bool Success
     */
    public static function multiple($check, array $options = [], $caseInsensitive = false)
    {
        $defaults = ['in' => null, 'max' => null, 'min' => null];
        $options += $defaults;

        $check = array_filter((array)$check);
        if (empty($check)) {
            return false;
        }
        if ($options['max'] && count($check) > $options['max']) {
            return false;
        }
        if ($options['min'] && count($check) < $options['min']) {
            return false;
        }
        if ($options['in'] && is_array($options['in'])) {
            if ($caseInsensitive) {
                $options['in'] = array_map('mb_strtolower', $options['in']);
            }
            foreach ($check as $val) {
                $strict = !is_numeric($val);
                if ($caseInsensitive) {
                    $val = mb_strtolower($val);
                }
                if (!in_array((string)$val, $options['in'], $strict)) {
                    return false;
                }
            }
        }
        return true;
    }

    /**
     * Checks if a value is numeric.
     *
     * @param string $check Value to check
     * @return bool Success
     */
    public static function numeric($check)
    {
        return is_numeric($check);
    }

    /**
     * Checks if a value is a natural number.
     *
     * @param string $check Value to check
     * @param bool $allowZero Set true to allow zero, defaults to false
     * @return bool Success
     * @see http://en.wikipedia.org/wiki/Natural_number
     */
    public static function naturalNumber($check, $allowZero = false)
    {
        $regex = $allowZero ? '/^(?:0|[1-9][0-9]*)$/' : '/^[1-9][0-9]*$/';
        return static::_check($check, $regex);
    }

    /**
     * Validates that a number is in specified range.
     *
     * If $lower and $upper are set, the range is inclusive.
     * If they are not set, will return true if $check is a
     * legal finite on this platform.
     *
     * @param string $check Value to check
     * @param int|float|null $lower Lower limit
     * @param int|float|null $upper Upper limit
     * @return bool Success
     */
    public static function range($check, $lower = null, $upper = null)
    {
        if (!is_numeric($check)) {
            return false;
        }
        if (isset($lower) && isset($upper)) {
            return ($check >= $lower && $check <= $upper);
        }
        return is_finite($check);
    }

    /**
     * Checks that a value is a valid URL according to http://www.w3.org/Addressing/URL/url-spec.txt
     *
     * The regex checks for the following component parts:
     *
     * - a valid, optional, scheme
     * - a valid ip address OR
     *   a valid domain name as defined by section 2.3.1 of http://www.ietf.org/rfc/rfc1035.txt
     *   with an optional port number
     * - an optional valid path
     * - an optional query string (get parameters)
     * - an optional fragment (anchor tag)
     *
     * @param string $check Value to check
     * @param bool $strict Require URL to be prefixed by a valid scheme (one of http(s)/ftp(s)/file/news/gopher)
     * @return bool Success
     */
    public static function url($check, $strict = false)
    {
        static::_populateIp();
        $validChars = '([' . preg_quote('!"$&\'()*+,-.@_:;=~[]') . '\/0-9\p{L}\p{N}]|(%[0-9a-f]{2}))';
        $regex = '/^(?:(?:https?|ftps?|sftp|file|news|gopher):\/\/)' . (!empty($strict) ? '' : '?') .
            '(?:' . static::$_pattern['IPv4'] . '|\[' . static::$_pattern['IPv6'] . '\]|' . static::$_pattern['hostname'] . ')(?::[1-9][0-9]{0,4})?' .
            '(?:\/?|\/' . $validChars . '*)?' .
            '(?:\?' . $validChars . '*)?' .
            '(?:#' . $validChars . '*)?$/iu';
        return static::_check($check, $regex);
    }

    /**
     * Checks if a value is in a given list. Comparison is case sensitive by default.
     *
     * @param string $check Value to check.
     * @param array $list List to check against.
     * @param bool $caseInsensitive Set to true for case insensitive comparison.
     * @return bool Success.
     */
    public static function inList($check, array $list, $caseInsensitive = false)
    {
        if ($caseInsensitive) {
            $list = array_map('mb_strtolower', $list);
            $check = mb_strtolower($check);
        } else {
            $list = array_map('strval', $list);
        }
        return in_array((string)$check, $list, true);
    }

    /**
     * Runs an user-defined validation.
     *
     * @param string|array $check value that will be validated in user-defined methods.
     * @param object $object class that holds validation method
     * @param string $method class method name for validation to run
     * @param array|null $args arguments to send to method
     * @return mixed user-defined class class method returns
     */
    public static function userDefined($check, $object, $method, $args = null)
    {
        return call_user_func_array([$object, $method], [$check, $args]);
    }

    /**
     * Checks that a value is a valid UUID - http://tools.ietf.org/html/rfc4122
     *
     * @param string $check Value to check
     * @return bool Success
     */
    public static function uuid($check)
    {
        $regex = '/^[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[0-5][a-fA-F0-9]{3}-[089aAbB][a-fA-F0-9]{3}-[a-fA-F0-9]{12}$/';
        return self::_check($check, $regex);
    }

    /**
     * Runs a regular expression match.
     *
     * @param string $check Value to check against the $regex expression
     * @param string $regex Regular expression
     * @return bool Success of match
     */
    protected static function _check($check, $regex)
    {
        if (is_string($regex) && preg_match($regex, $check)) {
            return true;
        }
        return false;
    }

    /**
     * Get the values to use when value sent to validation method is
     * an array.
     *
     * @param array $params Parameters sent to validation method
     * @return void
     */
    protected static function _defaults($params)
    {
        static::_reset();
        $defaults = [
            'check' => null,
            'regex' => null,
            'country' => null,
            'deep' => false,
            'type' => null
        ];
        $params += $defaults;
        if ($params['country'] !== null) {
            $params['country'] = mb_strtolower($params['country']);
        }
        return $params;
    }

    /**
     * Luhn algorithm
     *
     * @param string|array $check Value to check.
     * @param bool $deep If true performs deep check.
     * @return bool Success
     * @see http://en.wikipedia.org/wiki/Luhn_algorithm
     */
    public static function luhn($check, $deep = false)
    {
        if (is_array($check)) {
            extract(static::_defaults($check));
        }
        if ($deep !== true) {
            return true;
        }
        if ((int)$check === 0) {
            return false;
        }
        $sum = 0;
        $length = strlen($check);

        for ($position = 1 - ($length % 2); $position < $length; $position += 2) {
            $sum += $check[$position];
        }

        for ($position = ($length % 2); $position < $length; $position += 2) {
            $number = $check[$position] * 2;
            $sum += ($number < 10) ? $number : $number - 9;
        }

        return ($sum % 10 === 0);
    }

    /**
     * Checks the mime type of a file.
     *
     * @param string|array $check Value to check.
     * @param array|string $mimeTypes Array of mime types or regex pattern to check.
     * @return bool Success
     * @throws \RuntimeException when mime type can not be determined.
     * @throws \LogicException when ext/fileinfo is missing
     */
    public static function mimeType($check, $mimeTypes = [])
    {
        if (is_array($check) && isset($check['tmp_name'])) {
            $check = $check['tmp_name'];
        }

        if (!function_exists('finfo_open')) {
            throw new LogicException('ext/fileinfo is required for validating file mime types');
        }

        if (!is_file($check)) {
            throw new RuntimeException('Cannot validate mimetype for a missing file');
        }

        $finfo = finfo_open(FILEINFO_MIME);
        $finfo = finfo_file($finfo, $check);

        if (!$finfo) {
            throw new RuntimeException('Can not determine the mimetype.');
        }

        list($mime) = explode(';', $finfo);

        if (is_string($mimeTypes)) {
            return self::_check($mime, $mimeTypes);
        }

        foreach ($mimeTypes as $key => $val) {
            $mimeTypes[$key] = strtolower($val);
        }
        return in_array($mime, $mimeTypes);
    }

    /**
     * Checks the filesize
     *
     * @param string|array $check Value to check.
     * @param string|null $operator See `Validation::comparison()`.
     * @param int|string|null $size Size in bytes or human readable string like '5MB'.
     * @return bool Success
     */
    public static function fileSize($check, $operator = null, $size = null)
    {
        if (is_array($check) && isset($check['tmp_name'])) {
            $check = $check['tmp_name'];
        }

        if (is_string($size)) {
            $size = String::parseFileSize($size);
        }
        $filesize = filesize($check);

        return static::comparison($filesize, $operator, $size);
    }

    /**
     * Checking for upload errors
     *
     * @param string|array $check Value to check.
     * @param bool $allowNoFile Set to true to allow UPLOAD_ERR_NO_FILE as a pass.
     * @return bool
     * @see http://www.php.net/manual/en/features.file-upload.errors.php
     */
    public static function uploadError($check, $allowNoFile = false)
    {
        if (is_array($check) && isset($check['error'])) {
            $check = $check['error'];
        }
        if ($allowNoFile) {
            return in_array((int)$check, [UPLOAD_ERR_OK, UPLOAD_ERR_NO_FILE], true);
        }
        return (int)$check === UPLOAD_ERR_OK;
    }

    /**
     * Validate an uploaded file.
     *
     * Helps join `uploadError`, `fileSize` and `mimeType` into
     * one higher level validation method.
     *
     * ### Options
     *
     * - `types` - An array of valid mime types. If empty all types
     *   will be accepted. The `type` will not be looked at, instead
     *   the file type will be checked with ext/finfo.
     * - `minSize` - The minimum file size in bytes. Defaults to not checking.
     * - `maxSize` - The maximum file size in bytes. Defaults to not checking.
     * - `optional` - Whether or not this file is optional. Defaults to false.
     *   If true a missing file will pass the validator regardless of other constraints.
     *
     * @param array $file The uploaded file data from PHP.
     * @param array $options An array of options for the validation.
     * @return bool
     */
    public static function uploadedFile($file, $options = [])
    {
        $options += [
            'minSize' => null,
            'maxSize' => null,
            'types' => null,
            'optional' => false,
        ];
        if (!is_array($file)) {
            return false;
        }
        $keys = ['error', 'name', 'size', 'tmp_name', 'type'];
        ksort($file);
        if (array_keys($file) != $keys) {
            return false;
        }
        if (!static::uploadError($file, $options['optional'])) {
            return false;
        }
        if ($options['optional'] && (int)$file['error'] === UPLOAD_ERR_NO_FILE) {
            return true;
        }
        if (isset($options['minSize']) && !static::fileSize($file, '>=', $options['minSize'])) {
            return false;
        }
        if (isset($options['maxSize']) && !static::fileSize($file, '<=', $options['maxSize'])) {
            return false;
        }
        if (isset($options['types']) && !static::mimeType($file, $options['types'])) {
            return false;
        }
        return true;
    }

    /**
     * Lazily populate the IP address patterns used for validations
     *
     * @return void
     */
    protected static function _populateIp()
    {
        if (!isset(static::$_pattern['IPv6'])) {
            $pattern = '((([0-9A-Fa-f]{1,4}:){7}(([0-9A-Fa-f]{1,4})|:))|(([0-9A-Fa-f]{1,4}:){6}';
            $pattern .= '(:|((25[0-5]|2[0-4]\d|[01]?\d{1,2})(\.(25[0-5]|2[0-4]\d|[01]?\d{1,2})){3})';
            $pattern .= '|(:[0-9A-Fa-f]{1,4})))|(([0-9A-Fa-f]{1,4}:){5}((:((25[0-5]|2[0-4]\d|[01]?\d{1,2})';
            $pattern .= '(\.(25[0-5]|2[0-4]\d|[01]?\d{1,2})){3})?)|((:[0-9A-Fa-f]{1,4}){1,2})))|(([0-9A-Fa-f]{1,4}:)';
            $pattern .= '{4}(:[0-9A-Fa-f]{1,4}){0,1}((:((25[0-5]|2[0-4]\d|[01]?\d{1,2})(\.(25[0-5]|2[0-4]\d|[01]?\d{1,2}))';
            $pattern .= '{3})?)|((:[0-9A-Fa-f]{1,4}){1,2})))|(([0-9A-Fa-f]{1,4}:){3}(:[0-9A-Fa-f]{1,4}){0,2}';
            $pattern .= '((:((25[0-5]|2[0-4]\d|[01]?\d{1,2})(\.(25[0-5]|2[0-4]\d|[01]?\d{1,2})){3})?)|';
            $pattern .= '((:[0-9A-Fa-f]{1,4}){1,2})))|(([0-9A-Fa-f]{1,4}:){2}(:[0-9A-Fa-f]{1,4}){0,3}';
            $pattern .= '((:((25[0-5]|2[0-4]\d|[01]?\d{1,2})(\.(25[0-5]|2[0-4]\d|[01]?\d{1,2}))';
            $pattern .= '{3})?)|((:[0-9A-Fa-f]{1,4}){1,2})))|(([0-9A-Fa-f]{1,4}:)(:[0-9A-Fa-f]{1,4})';
            $pattern .= '{0,4}((:((25[0-5]|2[0-4]\d|[01]?\d{1,2})(\.(25[0-5]|2[0-4]\d|[01]?\d{1,2})){3})?)';
            $pattern .= '|((:[0-9A-Fa-f]{1,4}){1,2})))|(:(:[0-9A-Fa-f]{1,4}){0,5}((:((25[0-5]|2[0-4]';
            $pattern .= '\d|[01]?\d{1,2})(\.(25[0-5]|2[0-4]\d|[01]?\d{1,2})){3})?)|((:[0-9A-Fa-f]{1,4})';
            $pattern .= '{1,2})))|(((25[0-5]|2[0-4]\d|[01]?\d{1,2})(\.(25[0-5]|2[0-4]\d|[01]?\d{1,2})){3})))(%.+)?';

            static::$_pattern['IPv6'] = $pattern;
        }
        if (!isset(static::$_pattern['IPv4'])) {
            $pattern = '(?:(?:25[0-5]|2[0-4][0-9]|(?:(?:1[0-9])?|[1-9]?)[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|(?:(?:1[0-9])?|[1-9]?)[0-9])';
            static::$_pattern['IPv4'] = $pattern;
        }
    }

    /**
     * Reset internal variables for another validation run.
     *
     * @return void
     */
    protected static function _reset()
    {
        static::$errors = [];
    }
}