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/mvc/helpers/time

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1
<?php
/**
 * Time Helper class file.
 *
 * This is CakePHP 2.0 TimeHelper class updated to PHP5 syntax for Vork
 *
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright 2005-2010, Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright 2005-2010, Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @package       cake.libs.view.helpers
 * @since         CakePHP(tm) v 0.10.0.1076
 * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
 */

/**
 * Time Helper class for easy use of time data.
 *
 * Manipulation of time data.
 *
 * @package       cake.libs.view.helpers
 * @link http://book.cakephp.org/view/1470/Time
 */
class timeHelper{

    /**
     * The format to use when formatting a time using `TimeHelper::nice()`
     *
     * The format should use the locale strings as defined in the PHP docs under
     * `strftime` (http://php.net/manual/en/function.strftime.php)
     *
     * @var string
     * @see TimeHelper::format()
     */
        public $niceFormat = '%a, %b %eS %Y, %H:%M';

    /**
     * Converts a string representing the format for the function strftime and returns a
     * windows safe and i18n aware format.
     *
     * @param string $format Format with specifiers for strftime function.
     *    Accepts the special specifier %S which mimics th modifier S for date()
     * @param string UNIX timestamp
     * @return string windows safe and date() function compatible format for strftime
     */
        public function convertSpecifiers($format, $time = null) {
            if (!$time) {
                $time = time();
            }
            $this->_time = $time;
            return preg_replace_callback('/\%(\w+)/', array($this, '_translateSpecifier'), $format);
        }
    
    /**
     * Auxiliary function to translate a matched specifier element from a regular expresion into
     * a windows safe and i18n aware specifier
     *
     * @param array $specifier match from regular expression
     * @return string converted element
     * @access private
     */
    private function _translateSpecifier($specifier) {
        $basics = get::helper('cakeBasics');
        switch ($specifier[1]) {
            case 'a':
                $abday = $basics->_dc('cake', 'abday', 5);
                if (is_array($abday)) {
                    return $abday[date('w', $this->_time)];
                }
                break;
            case 'A':
                $day = $basics->_dc('cake', 'day', 5);
                if (is_array($day)) {
                    return $day[date('w', $this->_time)];
                }
                break;
            case 'c':
                $format = $basics->_dc('cake', 'd_t_fmt', 5);
                if ($format != 'd_t_fmt') {
                    return $this->convertSpecifiers($format, $this->_time);
                }
                break;
            case 'C':
                return sprintf("%02d", date('Y', $this->_time) / 100);
            case 'D':
                return '%m/%d/%y';
            case 'e':
                if (DS === '/') {
                    return '%e';
                }
                $day = date('j', $this->_time);
                if ($day < 10) {
                    $day = ' ' . $day;
                }
                return $day;
            case 'eS' :
                return date('jS', $this->_time);
            case 'b':
            case 'h':
                $months = $basics->_dc('cake', 'abmon', 5);
                if (is_array($months)) {
                    return $months[date('n', $this->_time) -1];
                }
                return '%b';
            case 'B':
                $months = $basics->_dc('cake', 'mon', 5);
                if (is_array($months)) {
                    return $months[date('n', $this->_time) -1];
                }
                break;
            case 'n':
                return "\n";
            case 'p':
            case 'P':
                $default = array('am' => 0, 'pm' => 1);
                $meridiem = $default[date('a',$this->_time)];
                $format = $basics->_dc('cake', 'am_pm', 5);
                if (is_array($format)) {
                    $meridiem = $format[$meridiem];
                    return ($specifier[1] == 'P') ? strtolower($meridiem) : strtoupper($meridiem);
                }
                break;
            case 'r':
                $complete = $basics->_dc('cake', 't_fmt_ampm', 5);
                if ($complete != 't_fmt_ampm') {
                    return str_replace('%p',$this->_translateSpecifier(array('%p', 'p')),$complete);
                }
                break;
            case 'R':
                return date('H:i', $this->_time);
            case 't':
                return "\t";
            case 'T':
                return '%H:%M:%S';
            case 'u':
                return ($weekDay = date('w', $this->_time)) ? $weekDay : 7;
            case 'x':
                $format = $basics->_dc('cake', 'd_fmt', 5);
                if ($format != 'd_fmt') {
                    return $this->convertSpecifiers($format, $this->_time);
                }
                break;
            case 'X':
                $format = $basics->_dc('cake', 't_fmt', 5);
                if ($format != 't_fmt') {
                    return $this->convertSpecifiers($format, $this->_time);
                }
                break;
        }
        return $specifier[0];
    }

    /**
     * Converts given time (in server's time zone) to user's local time, given his/her offset from GMT.
     *
     * @param string $serverTime UNIX timestamp
     * @param int $userOffset User's offset from GMT (in hours)
     * @return string UNIX timestamp
     */
    public function convert($serverTime, $userOffset) {
        $serverOffset = $this->serverOffset();
        $gmtTime = $serverTime - $serverOffset;
        $userTime = $gmtTime + $userOffset * (60*60);
        return $userTime;
    }

    /**
     * Returns server's offset from GMT in seconds.
     *
     * @return int Offset
     */
    public function serverOffset() {
        return date('Z', time());
    }

    /**
     * Returns a UNIX timestamp, given either a UNIX timestamp or a valid strtotime() date string.
     *
     * @param string $dateString Datetime string
     * @param int $userOffset User's offset from GMT (in hours)
     * @return string Parsed timestamp
     * @access public
     * @link http://book.cakephp.org/view/1471/Formatting
     */
    public function fromString($dateString, $userOffset = null) {
        if (empty($dateString)) {
            return false;
        }
        if (is_integer($dateString) || is_numeric($dateString)) {
            $date = intval($dateString);
        } else {
            $date = strtotime($dateString);
        }
        if ($userOffset !== null) {
            return $this->convert($date, $userOffset);
        }
        if ($date === -1) {
            return false;
        }
        return $date;
    }

    /**
     * Returns a nicely formatted date string for given Datetime string.
     *
     * See http://php.net/manual/en/function.strftime.php for information on formatting
     * using locale strings.
     *
     * @param string $dateString Datetime string or Unix timestamp
     * @param int $userOffset User's offset from GMT (in hours)
     * @param string $format The format to use. If null, `TimeHelper::$niceFormat` is used
     * @return string Formatted date string
     * @access public
     * @link http://book.cakephp.org/view/1471/Formatting
     */
    public function nice($dateString = null, $userOffset = null, $format = null) {
        if ($dateString != null) {
            $date = $this->fromString($dateString, $userOffset);
        } else {
            $date = time();
        }
        if (!$format) {
            $format = $this->niceFormat;
        }
        $format = $this->convertSpecifiers($format, $date);
        return strftime($format, $date);
    }

    /**
     * Returns a formatted descriptive date string for given datetime string.
     *
     * If the given date is today, the returned string could be "Today, 16:54".
     * If the given date was yesterday, the returned string could be "Yesterday, 16:54".
     * If $dateString's year is the current year, the returned string does not
     * include mention of the year.
     *
     * @param string $dateString Datetime string or Unix timestamp
     * @param int $userOffset User's offset from GMT (in hours)
     * @return string Described, relative date string
     * @access public
     * @link http://book.cakephp.org/view/1471/Formatting
     */
    public function niceShort($dateString = null, $userOffset = null) {
        $date = $dateString ? $this->fromString($dateString, $userOffset) : time();

        $y = $this->isThisYear($date) ? '' : ' %Y';
        $basics = get::helper('cakeBasics');
        if ($this->isToday($dateString, $userOffset)) {
            $ret = $basics->_d('cake', 'Today, %s', strftime("%H:%M", $date));
        } elseif ($this->wasYesterday($dateString, $userOffset)) {
            $ret = $basics->_d('cake', 'Yesterday, %s', strftime("%H:%M", $date));
        } else {
            $format = $this->convertSpecifiers("%b %eS{$y}, %H:%M", $date);
            $ret = strftime($format, $date);
        }

        return $ret;
    }

    /**
     * Returns a partial SQL string to search for all records between two dates.
     *
     * @param string $dateString Datetime string or Unix timestamp
     * @param string $end Datetime string or Unix timestamp
     * @param string $fieldName Name of database field to compare with
     * @param int $userOffset User's offset from GMT (in hours)
     * @return string Partial SQL string.
     * @access public
     * @link http://book.cakephp.org/view/1471/Formatting
     */
    public function daysAsSql($begin, $end, $fieldName, $userOffset = null) {
        $begin = $this->fromString($begin, $userOffset);
        $end = $this->fromString($end, $userOffset);
        $begin = date('Y-m-d', $begin) . ' 00:00:00';
        $end = date('Y-m-d', $end) . ' 23:59:59';

        return "($fieldName >= '$begin') AND ($fieldName <= '$end')";
    }

    /**
     * Returns a partial SQL string to search for all records between two times
     * occurring on the same day.
     *
     * @param string $dateString Datetime string or Unix timestamp
     * @param string $fieldName Name of database field to compare with
     * @param int $userOffset User's offset from GMT (in hours)
     * @return string Partial SQL string.
     * @access public
     * @link http://book.cakephp.org/view/1471/Formatting
     */
    public function dayAsSql($dateString, $fieldName, $userOffset = null) {
        $date = $this->fromString($dateString, $userOffset);
        return $this->daysAsSql($dateString, $dateString, $fieldName);
    }

    /**
     * Returns true if given datetime string is today.
     *
     * @param string $dateString Datetime string or Unix timestamp
     * @param int $userOffset User's offset from GMT (in hours)
     * @return boolean True if datetime string is today
     */
    public function isToday($dateString, $userOffset = null) {
        $date = $this->fromString($dateString, $userOffset);
        return date('Y-m-d', $date) == date('Y-m-d', time());
    }

    /**
     * Returns true if given datetime string is within this week.
     *
     * @param string $dateString
     * @param int $userOffset User's offset from GMT (in hours)
     * @return boolean True if datetime string is within current week
     * @access public
     * @link http://book.cakephp.org/view/1472/Testing-Time
     */
    public function isThisWeek($dateString, $userOffset = null) {
        $date = $this->fromString($dateString, $userOffset);
        return date('W o', $date) == date('W o', time());
    }

    /**
     * Returns true if given datetime string is within this month
     * @param string $dateString
     * @param int $userOffset User's offset from GMT (in hours)
     * @return boolean True if datetime string is within current month
     * @access public
     * @link http://book.cakephp.org/view/1472/Testing-Time
     */
    public function isThisMonth($dateString, $userOffset = null) {
        $date = $this->fromString($dateString);
        return date('m Y',$date) == date('m Y', time());
    }

    /**
     * Returns true if given datetime string is within current year.
     *
     * @param string $dateString Datetime string or Unix timestamp
     * @return boolean True if datetime string is within current year
     * @access public
     * @link http://book.cakephp.org/view/1472/Testing-Time
     */
    public function isThisYear($dateString, $userOffset = null) {
        $date = $this->fromString($dateString, $userOffset);
        return  date('Y', $date) == date('Y', time());
    }

    /**
     * Returns true if given datetime string was yesterday.
     *
     * @param string $dateString Datetime string or Unix timestamp
     * @param int $userOffset User's offset from GMT (in hours)
     * @return boolean True if datetime string was yesterday
     * @access public
     * @link http://book.cakephp.org/view/1472/Testing-Time
     *
     */
    public function wasYesterday($dateString, $userOffset = null) {
        $date = $this->fromString($dateString, $userOffset);
        return date('Y-m-d', $date) == date('Y-m-d', strtotime('yesterday'));
    }

    /**
     * Returns true if given datetime string is tomorrow.
     *
     * @param string $dateString Datetime string or Unix timestamp
     * @param int $userOffset User's offset from GMT (in hours)
     * @return boolean True if datetime string was yesterday
     * @access public
     * @link http://book.cakephp.org/view/1472/Testing-Time
     */
    public function isTomorrow($dateString, $userOffset = null) {
        $date = $this->fromString($dateString, $userOffset);
        return date('Y-m-d', $date) == date('Y-m-d', strtotime('tomorrow'));
    }

    /**
     * Returns the quarter
     *
     * @param string $dateString
     * @param boolean $range if true returns a range in Y-m-d format
     * @return boolean True if datetime string is within current week
     * @access public
     * @link http://book.cakephp.org/view/1471/Formatting
     */
    public function toQuarter($dateString, $range = false) {
        $time = $this->fromString($dateString);
        $date = ceil(date('m', $time) / 3);

        if ($range === true) {
            $range = 'Y-m-d';
        }

        if ($range !== false) {
            $year = date('Y', $time);

            switch ($date) {
                case 1:
                    $date = array($year.'-01-01', $year.'-03-31');
                    break;
                case 2:
                    $date = array($year.'-04-01', $year.'-06-30');
                    break;
                case 3:
                    $date = array($year.'-07-01', $year.'-09-30');
                    break;
                case 4:
                    $date = array($year.'-10-01', $year.'-12-31');
                    break;
            }
        }
        return $date;
    }

    /**
     * Returns a UNIX timestamp from a textual datetime description. Wrapper for PHP function strtotime().
     *
     * @param string $dateString Datetime string to be represented as a Unix timestamp
     * @param int $userOffset User's offset from GMT (in hours)
     * @return integer Unix timestamp
     * @access public
     * @link http://book.cakephp.org/view/1471/Formatting
     */
    public function toUnix($dateString, $userOffset = null) {
        return $this->fromString($dateString, $userOffset);
    }

    /**
     * Returns a date formatted for Atom RSS feeds.
     *
     * @param string $dateString Datetime string or Unix timestamp
     * @param int $userOffset User's offset from GMT (in hours)
     * @return string Formatted date string
     * @access public
     * @link http://book.cakephp.org/view/1471/Formatting
     */
    public function toAtom($dateString, $userOffset = null) {
        $date = $this->fromString($dateString, $userOffset);
        return date('Y-m-d\TH:i:s\Z', $date);
    }

    /**
     * Formats date for RSS feeds
     *
     * @param string $dateString Datetime string or Unix timestamp
     * @param int $userOffset User's offset from GMT (in hours)
     * @return string Formatted date string
     * @access public
     * @link http://book.cakephp.org/view/1471/Formatting
     */
    public function toRSS($dateString, $userOffset = null) {
        $date = $this->fromString($dateString, $userOffset);
        return date("r", $date);
    }

    /**
     * Returns either a relative date or a formatted date depending
     * on the difference between the current time and given datetime.
     * $datetime should be in a <i>strtotime</i> - parsable format, like MySQL's datetime datatype.
     *
     * ### Options:
     *
     * - `format` => a fall back format if the relative time is longer than the duration specified by end
     * - `end` => The end of relative time telling
     * - `userOffset` => Users offset from GMT (in hours)
     *
     * Relative dates look something like this:
     *    3 weeks, 4 days ago
     *    15 seconds ago
     *
     * Default date formatting is d/m/yy e.g: on 18/2/09
     *
     * The returned string includes 'ago' or 'on' and assumes you'll properly add a word
     * like 'Posted ' before the function output.
     *
     * @param string $dateString Datetime string or Unix timestamp
     * @param array $options Default format if timestamp is used in $dateString
     * @return string Relative time string.
     * @access public
     * @link http://book.cakephp.org/view/1471/Formatting
     */
    public function timeAgoInWords($dateTime, $options = array()) {
        $userOffset = null;
        if (is_array($options) && isset($options['userOffset'])) {
            $userOffset = $options['userOffset'];
        }
        $now = time();
        if (!is_null($userOffset)) {
            $now = $this->convert(time(), $userOffset);
        }
        $inSeconds = $this->fromString($dateTime, $userOffset);
        $backwards = ($inSeconds > $now);

        $format = 'j/n/y';
        $end = '+1 month';

        if (is_array($options)) {
            if (isset($options['format'])) {
                $format = $options['format'];
                unset($options['format']);
            }
            if (isset($options['end'])) {
                $end = $options['end'];
                unset($options['end']);
            }
        } else {
            $format = $options;
        }

        if ($backwards) {
            $futureTime = $inSeconds;
            $pastTime = $now;
        } else {
            $futureTime = $now;
            $pastTime = $inSeconds;
        }
        $diff = $futureTime - $pastTime;

        // If more than a week, then take into account the length of months
        if ($diff >= 604800) {
            $current = array();
            $date = array();

            list($future['H'], $future['i'], $future['s'], $future['d'], $future['m'], $future['Y']) 
        = explode('/', date('H/i/s/d/m/Y', $futureTime));

            list($past['H'], $past['i'], $past['s'], $past['d'], $past['m'], $past['Y']) 
        = explode('/', date('H/i/s/d/m/Y', $pastTime));
            $years = $months = $weeks = $days = $hours = $minutes = $seconds = 0;

            if ($future['Y'] == $past['Y'] && $future['m'] == $past['m']) {
                $months = 0;
                $years = 0;
            } else {
                if ($future['Y'] == $past['Y']) {
                    $months = $future['m'] - $past['m'];
                } else {
                    $years = $future['Y'] - $past['Y'];
                    $months = $future['m'] + ((12 * $years) - $past['m']);

                    if ($months >= 12) {
                        $years = floor($months / 12);
                        $months = $months - ($years * 12);
                    }

                    if ($future['m'] < $past['m'] && $future['Y'] - $past['Y'] == 1) {
                        $years --;
                    }
                }
            }

            if ($future['d'] >= $past['d']) {
                $days = $future['d'] - $past['d'];
            } else {
                $daysInPastMonth = date('t', $pastTime);
                $daysInFutureMonth = date('t', mktime(0, 0, 0, $future['m'] - 1, 1, $future['Y']));

                if (!$backwards) {
                    $days = ($daysInPastMonth - $past['d']) + $future['d'];
                } else {
                    $days = ($daysInFutureMonth - $past['d']) + $future['d'];
                }

                if ($future['m'] != $past['m']) {
                    $months --;
                }
            }

            if ($months == 0 && $years >= 1 && $diff < ($years * 31536000)) {
                $months = 11;
                $years --;
            }

            if ($months >= 12) {
                $years = $years + 1;
                $months = $months - 12;
            }

            if ($days >= 7) {
                $weeks = floor($days / 7);
                $days = $days - ($weeks * 7);
            }
        } else {
            $years = $months = $weeks = 0;
            $days = floor($diff / 86400);

            $diff = $diff - ($days * 86400);

            $hours = floor($diff / 3600);
            $diff = $diff - ($hours * 3600);

            $minutes = floor($diff / 60);
            $diff = $diff - ($minutes * 60);
            $seconds = $diff;
        }
        $relativeDate = '';
        $diff = $futureTime - $pastTime;
        $basics = get::helper('cakeBasics');
        if ($diff > abs($now - $this->fromString($end))) {
            $relativeDate = $basics->_d('cake', 'on %s', date($format, $inSeconds));
        } else {
            if ($years > 0) {
                // years and months and days
                $relativeDate .= ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d year', '%d years', $years, $years);
                $relativeDate .= $months > 0 ? ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d month', '%d months', $months, $months) : '';
                $relativeDate .= $weeks > 0 ? ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d week', '%d weeks', $weeks, $weeks) : '';
                $relativeDate .= $days > 0 ? ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d day', '%d days', $days, $days) : '';
            } elseif (abs($months) > 0) {
                // months, weeks and days
                $relativeDate .= ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d month', '%d months', $months, $months);
                $relativeDate .= $weeks > 0 ? ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d week', '%d weeks', $weeks, $weeks) : '';
                $relativeDate .= $days > 0 ? ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d day', '%d days', $days, $days) : '';
            } elseif (abs($weeks) > 0) {
                // weeks and days
                $relativeDate .= ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d week', '%d weeks', $weeks, $weeks);
                $relativeDate .= $days > 0 ? ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d day', '%d days', $days, $days) : '';
            } elseif (abs($days) > 0) {
                // days and hours
                $relativeDate .= ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d day', '%d days', $days, $days);
                $relativeDate .= $hours > 0 ? ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d hour', '%d hours', $hours, $hours) : '';
            } elseif (abs($hours) > 0) {
                // hours and minutes
                $relativeDate .= ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d hour', '%d hours', $hours, $hours);
                $relativeDate .= $minutes > 0 ? ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d minute', '%d minutes', $minutes, $minutes) : '';
            } elseif (abs($minutes) > 0) {
                // minutes only
                $relativeDate .= ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d minute', '%d minutes', $minutes, $minutes);
            } else {
                // seconds only
                $relativeDate .= ($relativeDate ? ', ' : '') . 
        $basics->_dn('cake', '%d second', '%d seconds', $seconds, $seconds);
            }

            if (!$backwards) {
                $relativeDate = $basics->_d('cake', '%s ago', $relativeDate);
            }
        }
        return $relativeDate;
    }

    /**
     * Returns true if specified datetime was within the interval specified, else false.
     *
     * @param mixed $timeInterval the numeric value with space then time type.
     *    Example of valid types: 6 hours, 2 days, 1 minute.
     * @param mixed $dateString the datestring or unix timestamp to compare
     * @param int $userOffset User's offset from GMT (in hours)
     * @return bool
     * @access public
     * @link http://book.cakephp.org/view/1472/Testing-Time
     */
    public function wasWithinLast($timeInterval, $dateString, $userOffset = null) {
        $tmp = str_replace(' ', '', $timeInterval);
        if (is_numeric($tmp)) {
            $basics = get::helper('cakeBasics');
            $timeInterval = $tmp . ' ' . $basics->_d('cake', 'days');
        }

        $date = $this->fromString($dateString, $userOffset);
        $interval = $this->fromString('-'.$timeInterval);

        if ($date >= $interval && $date <= time()) {
            return true;
        }

        return false;
    }

    /**
     * Returns gmt, given either a UNIX timestamp or a valid strtotime() date string.
     *
     * @param string $dateString Datetime string
     * @return string Formatted date string
     * @access public
     * @link http://book.cakephp.org/view/1471/Formatting
     */
    public function gmt($string = null) {
        if ($string != null) {
            $string = $this->fromString($string);
        } else {
            $string = time();
        }
        $string = $this->fromString($string);
        $hour = intval(date("G", $string));
        $minute = intval(date("i", $string));
        $second = intval(date("s", $string));
        $month = intval(date("n", $string));
        $day = intval(date("j", $string));
        $year = intval(date("Y", $string));

        return gmmktime($hour, $minute, $second, $month, $day, $year);
    }

    /**
     * Returns a formatted date string, given either a UNIX timestamp or a valid strtotime() date string.
     * This function also accepts a time string and a format string as first and second parameters.
     * In that case this function behaves as a wrapper for TimeHelper::i18nFormat()
     *
     * @param string $format date format string (or a DateTime string)
     * @param string $dateString Datetime string (or a date format string)
     * @param boolean $invalid flag to ignore results of fromString == false
     * @param int $userOffset User's offset from GMT (in hours)
     * @return string Formatted date string
     */
    public function format($format, $date = null, $invalid = false, $userOffset = null) {
        $time = $this->fromString($date, $userOffset);
        $_time = $this->fromString($format, $userOffset);

        if (is_numeric($_time) && $time === false) {
            $format = $date;
            return $this->i18nFormat($_time, $format, $invalid, $userOffset);
        }
        if ($time === false && $invalid !== false) {
            return $invalid;
        }
        return date($format, $time);
    }

    /**
     * Returns a formatted date string, given either a UNIX timestamp or a valid strtotime() date string.
     * It take in account the default date format for the current language if a LC_TIME file is used.
     *
     * @param string $dateString Datetime string
     * @param string $format strftime format string.
     * @param boolean $invalid flag to ignore results of fromString == false
     * @param int $userOffset User's offset from GMT (in hours)
     * @return string Formatted and translated date string @access public
     */
    public function i18nFormat($date, $format = null, $invalid = false, $userOffset = null) {
        $date = $this->fromString($date, $userOffset);
        if ($date === false && $invalid !== false) {
            return $invalid;
        }
        if (empty($format)) {
            $format = '%x';
        }
        $format = $this->convertSpecifiers($format, $date);
        return strftime($format, $date);
    }
}