public static function convertLocalTimeToTimestamp($time)
 {
     // time to convert (just an example)
     // $time = 'Tuesday, April 21, 2009 2:32:46 PM';
     // set this to the time zone provided by the user
     // $tz = get_option('wpla_local_timezone');
     $tz = get_option('timezone_string');
     if (!$tz) {
         $tz = wc_timezone_string();
     }
     // 'Europe/London'
     // create the DateTimeZone object for later
     $dtzone = new DateTimeZone($tz);
     // now create the DateTime object for this time and user time zone
     $dtime = new DateTime($time, $dtzone);
     // print the timestamp
     $timestamp = $dtime->format('U');
     return $timestamp;
 }

 /**
  * Format a unix timestamp or MySQL datetime into an RFC3339 datetime
  *
  * @since 2.1
  * @param int|string $timestamp unix timestamp or MySQL datetime
  * @param bool $convert_to_utc
  * @return string RFC3339 datetime
  */
 public function format_datetime($timestamp, $convert_to_utc = false)
 {
     if ($convert_to_utc) {
         $timezone = new DateTimeZone(wc_timezone_string());
     } else {
         $timezone = new DateTimeZone('UTC');
     }
     try {
         if (is_numeric($timestamp)) {
             $date = new DateTime("@{$timestamp}");
         } else {
             $date = new DateTime($timestamp, $timezone);
         }
         // convert to UTC by adjusting the time based on the offset of the site's timezone
         if ($convert_to_utc) {
             $date->modify(-1 * $date->getOffset() . ' seconds');
         }
     } catch (Exception $e) {
         $date = new DateTime('@0');
     }
     return $date->format('Y-m-d\\TH:i:s\\Z');
 }

/**
 * @deprecated
 */
function woocommerce_timezone_string()
{
    return wc_timezone_string();
}

 /**
  * Test wc_timezone_string().
  *
  * @since 2.2
  */
 public function test_wc_timezone_string()
 {
     // test when timezone string exists
     update_option('timezone_string', 'America/New_York');
     $this->assertEquals('America/New_York', wc_timezone_string());
     // restore default
     update_option('timezone_string', '');
     // test with missing UTC offset
     delete_option('gmt_offset');
     $this->assertEquals('UTC', wc_timezone_string());
     // test with manually set UTC offset
     update_option('gmt_offset', -4);
     $this->assertEquals('America/Halifax', wc_timezone_string());
     // test with invalid offset
     update_option('gmt_offset', 99);
     $this->assertEquals('UTC', wc_timezone_string());
     // restore default
     update_option('gmt_offset', '0');
 }

    /**
     * Formats order note
     *
     * @since  1.0
     * @param string $to number SMS message was sent to
     * @param int $sent_timestamp integer timestamp for when message was sent
     * @param string $message SMS message sent
     * @param string $status order status
     * @param bool $error true if there was an error sending SMS, false otherwise
     * @return string HTML-formatted order note
     */
    private function format_order_note($to, $sent_timestamp, $message, $status, $error)
    {
        try {
            // get datetime object from unix timestamp
            $datetime = new DateTime("@{$sent_timestamp}", new DateTimeZone('UTC'));
            // change timezone to site timezone
            $datetime->setTimezone(new DateTimeZone(wc_timezone_string()));
            // return datetime localized to site date/time settings
            $formatted_datetime = date_i18n(wc_date_format() . ' ' . wc_time_format(), $sent_timestamp + $datetime->getOffset());
        } catch (Exception $e) {
            // log error and set datetime for SMS to 'N/A'
            wc_twilio_sms()->log($e->getMessage());
            $formatted_datetime = __('N/A', WC_Twilio_SMS::TEXT_DOMAIN);
        }
        ob_start();
        ?>
	  	<p><strong><?php 
        _e('SMS Notification', WC_Twilio_SMS::TEXT_DOMAIN);
        ?>
</strong></p>
		<p><strong><?php 
        _e('To', WC_Twilio_SMS::TEXT_DOMAIN);
        ?>
: </strong><?php 
        echo esc_html($to);
        ?>
</p>
		<p><strong><?php 
        _e('Date Sent', WC_Twilio_SMS::TEXT_DOMAIN);
        ?>
: </strong><?php 
        echo esc_html($formatted_datetime);
        ?>
</p>
		<p><strong><?php 
        _e('Message', WC_Twilio_SMS::TEXT_DOMAIN);
        ?>
: </strong><?php 
        echo esc_html($message);
        ?>
</p>
		<p><strong><?php 
        _e('Status', WC_Twilio_SMS::TEXT_DOMAIN);
        ?>
: <span style="<?php 
        echo $error ? 'color: red;' : 'color: green;';
        ?>
"><?php 
        echo esc_html($status);
        ?>
</span></strong></p>
		<?php 
        return ob_get_clean();
    }

 /**
  * Compatibility for the wc_timezone_string() function, which only
  * exists in 2.1+
  *
  * @since 2.0
  * @return string a valid PHP timezone string for the site
  */
 public static function wc_timezone_string()
 {
     if (self::is_wc_version_gte_2_1()) {
         return wc_timezone_string();
     } else {
         // if site timezone string exists, return it
         if ($timezone = get_option('timezone_string')) {
             return $timezone;
         }
         // get UTC offset, if it isn't set then return UTC
         if (0 === ($utc_offset = get_option('gmt_offset', 0))) {
             return 'UTC';
         }
         // adjust UTC offset from hours to seconds
         $utc_offset *= 3600;
         // attempt to guess the timezone string from the UTC offset
         $timezone = timezone_name_from_abbr('', $utc_offset);
         // last try, guess timezone string manually
         if (false === $timezone) {
             $is_dst = date('I');
             foreach (timezone_abbreviations_list() as $abbr) {
                 foreach ($abbr as $city) {
                     if ($city['dst'] == $is_dst && $city['offset'] == $utc_offset) {
                         return $city['timezone_id'];
                     }
                 }
             }
         }
         // fallback to UTC
         return 'UTC';
     }
 }