eventespresso / event-espresso-core

espresso.php

Indentation +192 added lines, -192 removed lines

@@ -38,217 +38,217 @@
  * @since       4.0
  */
 if (function_exists('espresso_version')) {
-    if (! function_exists('espresso_duplicate_plugin_error')) {
-        /**
-         *    espresso_duplicate_plugin_error
-         *    displays if more than one version of EE is activated at the same time
-         */
-        function espresso_duplicate_plugin_error()
-        {
-            ?>
+	if (! function_exists('espresso_duplicate_plugin_error')) {
+		/**
+		 *    espresso_duplicate_plugin_error
+		 *    displays if more than one version of EE is activated at the same time
+		 */
+		function espresso_duplicate_plugin_error()
+		{
+			?>
             <div class="error">
                 <p>
                     <?php
-                    echo esc_html__(
-                        'Can not run multiple versions of Event Espresso! One version has been automatically deactivated. Please verify that you have the correct version you want still active.',
-                        'event_espresso'
-                    ); ?>
+					echo esc_html__(
+						'Can not run multiple versions of Event Espresso! One version has been automatically deactivated. Please verify that you have the correct version you want still active.',
+						'event_espresso'
+					); ?>
                 </p>
             </div>
             <?php
-            espresso_deactivate_plugin(plugin_basename(__FILE__));
-        }
-    }
-    add_action('admin_notices', 'espresso_duplicate_plugin_error', 1);
+			espresso_deactivate_plugin(plugin_basename(__FILE__));
+		}
+	}
+	add_action('admin_notices', 'espresso_duplicate_plugin_error', 1);
 
 } else {
-    define('EE_MIN_PHP_VER_REQUIRED', '5.3.9');
-    if (! version_compare(PHP_VERSION, EE_MIN_PHP_VER_REQUIRED, '>=')) {
-        /**
-         * espresso_minimum_php_version_error
-         *
-         * @return void
-         */
-        function espresso_minimum_php_version_error()
-        {
-            ?>
+	define('EE_MIN_PHP_VER_REQUIRED', '5.3.9');
+	if (! version_compare(PHP_VERSION, EE_MIN_PHP_VER_REQUIRED, '>=')) {
+		/**
+		 * espresso_minimum_php_version_error
+		 *
+		 * @return void
+		 */
+		function espresso_minimum_php_version_error()
+		{
+			?>
             <div class="error">
                 <p>
                     <?php
-                    printf(
-                        esc_html__(
-                            'We\'re sorry, but Event Espresso requires PHP version %1$s or greater in order to operate. You are currently running version %2$s.%3$sIn order to update your version of PHP, you will need to contact your current hosting provider.%3$sFor information on stable PHP versions, please go to %4$s.',
-                            'event_espresso'
-                        ),
-                        EE_MIN_PHP_VER_REQUIRED,
-                        PHP_VERSION,
-                        '<br/>',
-                        '<a href="http://php.net/downloads.php">http://php.net/downloads.php</a>'
-                    );
-                    ?>
+					printf(
+						esc_html__(
+							'We\'re sorry, but Event Espresso requires PHP version %1$s or greater in order to operate. You are currently running version %2$s.%3$sIn order to update your version of PHP, you will need to contact your current hosting provider.%3$sFor information on stable PHP versions, please go to %4$s.',
+							'event_espresso'
+						),
+						EE_MIN_PHP_VER_REQUIRED,
+						PHP_VERSION,
+						'<br/>',
+						'<a href="http://php.net/downloads.php">http://php.net/downloads.php</a>'
+					);
+					?>
                 </p>
             </div>
             <?php
-            espresso_deactivate_plugin(plugin_basename(__FILE__));
-        }
+			espresso_deactivate_plugin(plugin_basename(__FILE__));
+		}
 
-        add_action('admin_notices', 'espresso_minimum_php_version_error', 1);
-    } else {
-        define('EVENT_ESPRESSO_MAIN_FILE', __FILE__);
-        /**
-         * espresso_version
-         * Returns the plugin version
-         *
-         * @return string
-         */
-        function espresso_version()
-        {
-            return apply_filters('FHEE__espresso__espresso_version', '4.9.54.rc.010');
-        }
+		add_action('admin_notices', 'espresso_minimum_php_version_error', 1);
+	} else {
+		define('EVENT_ESPRESSO_MAIN_FILE', __FILE__);
+		/**
+		 * espresso_version
+		 * Returns the plugin version
+		 *
+		 * @return string
+		 */
+		function espresso_version()
+		{
+			return apply_filters('FHEE__espresso__espresso_version', '4.9.54.rc.010');
+		}
 
-        /**
-         * espresso_plugin_activation
-         * adds a wp-option to indicate that EE has been activated via the WP admin plugins page
-         */
-        function espresso_plugin_activation()
-        {
-            update_option('ee_espresso_activation', true);
-        }
+		/**
+		 * espresso_plugin_activation
+		 * adds a wp-option to indicate that EE has been activated via the WP admin plugins page
+		 */
+		function espresso_plugin_activation()
+		{
+			update_option('ee_espresso_activation', true);
+		}
 
-        register_activation_hook(EVENT_ESPRESSO_MAIN_FILE, 'espresso_plugin_activation');
-        /**
-         *    espresso_load_error_handling
-         *    this function loads EE's class for handling exceptions and errors
-         */
-        function espresso_load_error_handling()
-        {
-            static $error_handling_loaded = false;
-            if ($error_handling_loaded) {
-                return;
-            }
-            // load debugging tools
-            if (WP_DEBUG === true && is_readable(EE_HELPERS . 'EEH_Debug_Tools.helper.php')) {
-                require_once   EE_HELPERS . 'EEH_Debug_Tools.helper.php';
-                \EEH_Debug_Tools::instance();
-            }
-            // load error handling
-            if (is_readable(EE_CORE . 'EE_Error.core.php')) {
-                require_once EE_CORE . 'EE_Error.core.php';
-            } else {
-                wp_die(esc_html__('The EE_Error core class could not be loaded.', 'event_espresso'));
-            }
-            $error_handling_loaded = true;
-        }
+		register_activation_hook(EVENT_ESPRESSO_MAIN_FILE, 'espresso_plugin_activation');
+		/**
+		 *    espresso_load_error_handling
+		 *    this function loads EE's class for handling exceptions and errors
+		 */
+		function espresso_load_error_handling()
+		{
+			static $error_handling_loaded = false;
+			if ($error_handling_loaded) {
+				return;
+			}
+			// load debugging tools
+			if (WP_DEBUG === true && is_readable(EE_HELPERS . 'EEH_Debug_Tools.helper.php')) {
+				require_once   EE_HELPERS . 'EEH_Debug_Tools.helper.php';
+				\EEH_Debug_Tools::instance();
+			}
+			// load error handling
+			if (is_readable(EE_CORE . 'EE_Error.core.php')) {
+				require_once EE_CORE . 'EE_Error.core.php';
+			} else {
+				wp_die(esc_html__('The EE_Error core class could not be loaded.', 'event_espresso'));
+			}
+			$error_handling_loaded = true;
+		}
 
-        /**
-         *    espresso_load_required
-         *    given a class name and path, this function will load that file or throw an exception
-         *
-         * @param    string $classname
-         * @param    string $full_path_to_file
-         * @throws    EE_Error
-         */
-        function espresso_load_required($classname, $full_path_to_file)
-        {
-            if (is_readable($full_path_to_file)) {
-                require_once $full_path_to_file;
-            } else {
-                throw new \EE_Error (
-                    sprintf(
-                        esc_html__(
-                            'The %s class file could not be located or is not readable due to file permissions.',
-                            'event_espresso'
-                        ),
-                        $classname
-                    )
-                );
-            }
-        }
+		/**
+		 *    espresso_load_required
+		 *    given a class name and path, this function will load that file or throw an exception
+		 *
+		 * @param    string $classname
+		 * @param    string $full_path_to_file
+		 * @throws    EE_Error
+		 */
+		function espresso_load_required($classname, $full_path_to_file)
+		{
+			if (is_readable($full_path_to_file)) {
+				require_once $full_path_to_file;
+			} else {
+				throw new \EE_Error (
+					sprintf(
+						esc_html__(
+							'The %s class file could not be located or is not readable due to file permissions.',
+							'event_espresso'
+						),
+						$classname
+					)
+				);
+			}
+		}
 
-        /**
-         * @since 4.9.27
-         * @throws \EE_Error
-         * @throws \EventEspresso\core\exceptions\InvalidInterfaceException
-         * @throws \EventEspresso\core\exceptions\InvalidEntityException
-         * @throws \EventEspresso\core\exceptions\InvalidIdentifierException
-         * @throws \EventEspresso\core\exceptions\InvalidClassException
-         * @throws \EventEspresso\core\exceptions\InvalidDataTypeException
-         * @throws \EventEspresso\core\services\container\exceptions\ServiceExistsException
-         * @throws \EventEspresso\core\services\container\exceptions\ServiceNotFoundException
-         * @throws \OutOfBoundsException
-         */
-        function bootstrap_espresso()
-        {
-            require_once __DIR__ . '/core/espresso_definitions.php';
-            try {
-                espresso_load_error_handling();
-                espresso_load_required(
-                    'EEH_Base',
-                    EE_CORE . 'helpers' . DS . 'EEH_Base.helper.php'
-                );
-                espresso_load_required(
-                    'EEH_File',
-                    EE_CORE . 'interfaces' . DS . 'EEHI_File.interface.php'
-                );
-                espresso_load_required(
-                    'EEH_File',
-                    EE_CORE . 'helpers' . DS . 'EEH_File.helper.php'
-                );
-                espresso_load_required(
-                    'EEH_Array',
-                    EE_CORE . 'helpers' . DS . 'EEH_Array.helper.php'
-                );
-                // instantiate and configure PSR4 autoloader
-                espresso_load_required(
-                    'Psr4Autoloader',
-                    EE_CORE . 'Psr4Autoloader.php'
-                );
-                espresso_load_required(
-                    'EE_Psr4AutoloaderInit',
-                    EE_CORE . 'EE_Psr4AutoloaderInit.core.php'
-                );
-                $AutoloaderInit = new EE_Psr4AutoloaderInit();
-                $AutoloaderInit->initializeAutoloader();
-                espresso_load_required(
-                    'EE_Request',
-                    EE_CORE . 'request_stack' . DS . 'EE_Request.core.php'
-                );
-                espresso_load_required(
-                    'EE_Response',
-                    EE_CORE . 'request_stack' . DS . 'EE_Response.core.php'
-                );
-                espresso_load_required(
-                    'EE_Bootstrap',
-                    EE_CORE . 'EE_Bootstrap.core.php'
-                );
-                // bootstrap EE and the request stack
-                new EE_Bootstrap(
-                    new EE_Request($_GET, $_POST, $_COOKIE),
-                    new EE_Response()
-                );
-            } catch (Exception $e) {
-                require_once EE_CORE . 'exceptions' . DS . 'ExceptionStackTraceDisplay.php';
-                new EventEspresso\core\exceptions\ExceptionStackTraceDisplay($e);
-            }
-        }
-        bootstrap_espresso();
-    }
+		/**
+		 * @since 4.9.27
+		 * @throws \EE_Error
+		 * @throws \EventEspresso\core\exceptions\InvalidInterfaceException
+		 * @throws \EventEspresso\core\exceptions\InvalidEntityException
+		 * @throws \EventEspresso\core\exceptions\InvalidIdentifierException
+		 * @throws \EventEspresso\core\exceptions\InvalidClassException
+		 * @throws \EventEspresso\core\exceptions\InvalidDataTypeException
+		 * @throws \EventEspresso\core\services\container\exceptions\ServiceExistsException
+		 * @throws \EventEspresso\core\services\container\exceptions\ServiceNotFoundException
+		 * @throws \OutOfBoundsException
+		 */
+		function bootstrap_espresso()
+		{
+			require_once __DIR__ . '/core/espresso_definitions.php';
+			try {
+				espresso_load_error_handling();
+				espresso_load_required(
+					'EEH_Base',
+					EE_CORE . 'helpers' . DS . 'EEH_Base.helper.php'
+				);
+				espresso_load_required(
+					'EEH_File',
+					EE_CORE . 'interfaces' . DS . 'EEHI_File.interface.php'
+				);
+				espresso_load_required(
+					'EEH_File',
+					EE_CORE . 'helpers' . DS . 'EEH_File.helper.php'
+				);
+				espresso_load_required(
+					'EEH_Array',
+					EE_CORE . 'helpers' . DS . 'EEH_Array.helper.php'
+				);
+				// instantiate and configure PSR4 autoloader
+				espresso_load_required(
+					'Psr4Autoloader',
+					EE_CORE . 'Psr4Autoloader.php'
+				);
+				espresso_load_required(
+					'EE_Psr4AutoloaderInit',
+					EE_CORE . 'EE_Psr4AutoloaderInit.core.php'
+				);
+				$AutoloaderInit = new EE_Psr4AutoloaderInit();
+				$AutoloaderInit->initializeAutoloader();
+				espresso_load_required(
+					'EE_Request',
+					EE_CORE . 'request_stack' . DS . 'EE_Request.core.php'
+				);
+				espresso_load_required(
+					'EE_Response',
+					EE_CORE . 'request_stack' . DS . 'EE_Response.core.php'
+				);
+				espresso_load_required(
+					'EE_Bootstrap',
+					EE_CORE . 'EE_Bootstrap.core.php'
+				);
+				// bootstrap EE and the request stack
+				new EE_Bootstrap(
+					new EE_Request($_GET, $_POST, $_COOKIE),
+					new EE_Response()
+				);
+			} catch (Exception $e) {
+				require_once EE_CORE . 'exceptions' . DS . 'ExceptionStackTraceDisplay.php';
+				new EventEspresso\core\exceptions\ExceptionStackTraceDisplay($e);
+			}
+		}
+		bootstrap_espresso();
+	}
 }
 if (! function_exists('espresso_deactivate_plugin')) {
-    /**
-     *    deactivate_plugin
-     * usage:  espresso_deactivate_plugin( plugin_basename( __FILE__ ));
-     *
-     * @access public
-     * @param string $plugin_basename - the results of plugin_basename( __FILE__ ) for the plugin's main file
-     * @return    void
-     */
-    function espresso_deactivate_plugin($plugin_basename = '')
-    {
-        if (! function_exists('deactivate_plugins')) {
-            require_once ABSPATH . 'wp-admin/includes/plugin.php';
-        }
-        unset($_GET['activate'], $_REQUEST['activate']);
-        deactivate_plugins($plugin_basename);
-    }
+	/**
+	 *    deactivate_plugin
+	 * usage:  espresso_deactivate_plugin( plugin_basename( __FILE__ ));
+	 *
+	 * @access public
+	 * @param string $plugin_basename - the results of plugin_basename( __FILE__ ) for the plugin's main file
+	 * @return    void
+	 */
+	function espresso_deactivate_plugin($plugin_basename = '')
+	{
+		if (! function_exists('deactivate_plugins')) {
+			require_once ABSPATH . 'wp-admin/includes/plugin.php';
+		}
+		unset($_GET['activate'], $_REQUEST['activate']);
+		deactivate_plugins($plugin_basename);
+	}
 }

core/helpers/EEH_DTT_Helper.helper.php

Indentation +1221 added lines, -1221 removed lines

@@ -15,382 +15,382 @@ 
 {
 
 
-    /**
-     * return the timezone set for the WP install
-     *
-     * @return string valid timezone string for PHP DateTimeZone() class
-     * @throws EE_Error
-     */
-    public static function get_timezone()
-    {
-        return EEH_DTT_Helper::get_valid_timezone_string();
-    }
-
-
-    /**
-     * get_valid_timezone_string
-     *    ensures that a valid timezone string is returned
-     *
-     * @param string $timezone_string
-     * @return string
-     * @throws EE_Error
-     */
-    public static function get_valid_timezone_string($timezone_string = '')
-    {
-        // if passed a value, then use that, else get WP option
-        $timezone_string = ! empty($timezone_string) ? $timezone_string : (string) get_option('timezone_string');
-        // value from above exists, use that, else get timezone string from gmt_offset
-        $timezone_string = ! empty($timezone_string)
-            ? $timezone_string
-            : EEH_DTT_Helper::get_timezone_string_from_gmt_offset();
-        EEH_DTT_Helper::validate_timezone($timezone_string);
-        return $timezone_string;
-    }
-
-
-    /**
-     * This only purpose for this static method is to validate that the incoming timezone is a valid php timezone.
-     *
-     * @static
-     * @param  string $timezone_string Timezone string to check
-     * @param bool    $throw_error
-     * @return bool
-     * @throws EE_Error
-     */
-    public static function validate_timezone($timezone_string, $throw_error = true)
-    {
-        // easiest way to test a timezone string is just see if it throws an error when you try to create a DateTimeZone object with it
-        try {
-            new DateTimeZone($timezone_string);
-        } catch (Exception $e) {
-            // sometimes we take exception to exceptions
-            if (! $throw_error) {
-                return false;
-            }
-            throw new EE_Error(
-                sprintf(
-                    esc_html__(
-                        'The timezone given (%1$s), is invalid, please check with %2$sthis list%3$s for what valid timezones can be used',
-                        'event_espresso'
-                    ),
-                    $timezone_string,
-                    '<a href="http://www.php.net/manual/en/timezones.php">',
-                    '</a>'
-                )
-            );
-        }
-        return true;
-    }
-
-
-    /**
-     * _create_timezone_object_from_timezone_name
-     *
-     * @param float|string $gmt_offset
-     * @return string
-     * @throws EE_Error
-     */
-    public static function get_timezone_string_from_gmt_offset($gmt_offset = '')
-    {
-        $timezone_string = 'UTC';
-        //if there is no incoming gmt_offset, then because WP hooks in on timezone_string, we need to see if that is
-        //set because it will override `gmt_offset` via `pre_get_option` filter.  If that's set, then let's just use
-        //that!  Otherwise we'll leave timezone_string at the default of 'UTC' before doing other logic.
-        if ($gmt_offset === '') {
-            //autoloaded so no need to set to a variable.  There will not be multiple hits to the db.
-            if (get_option('timezone_string')) {
-                return (string) get_option('timezone_string');
-            }
-        }
-        $gmt_offset = $gmt_offset !== '' ? $gmt_offset : (string) get_option('gmt_offset');
-        $gmt_offset = (float) $gmt_offset;
-        //if $gmt_offset is 0, then just return UTC
-        if ($gmt_offset === (float) 0) {
-            return $timezone_string;
-        }
-        if ($gmt_offset !== '') {
-            // convert GMT offset to seconds
-            $gmt_offset *= HOUR_IN_SECONDS;
-            // although we don't know the TZ abbreviation, we know the UTC offset
-            $timezone_string = timezone_name_from_abbr(null, $gmt_offset);
-            //only use this timezone_string IF it's current offset matches the given offset
-            if(! empty($timezone_string)) {
-                $offset  = null;
-                try {
-                    $offset = self::get_timezone_offset(new DateTimeZone($timezone_string));
-                    if ($offset !== $gmt_offset) {
-                        $timezone_string = false;
-                    }
-                } catch (Exception $e) {
-                    $timezone_string = false;
-                }
-            }
-        }
-        // better have a valid timezone string by now, but if not, sigh... loop thru  the timezone_abbreviations_list()...
-        $timezone_string = $timezone_string !== false
-            ? $timezone_string
-            : EEH_DTT_Helper::get_timezone_string_from_abbreviations_list($gmt_offset);
-        return $timezone_string;
-    }
-
-
-    /**
-     * Gets the site's GMT offset based on either the timezone string
-     * (in which case teh gmt offset will vary depending on the location's
-     * observance of daylight savings time) or the gmt_offset wp option
-     *
-     * @return int seconds offset
-     */
-    public static function get_site_timezone_gmt_offset()
-    {
-        $timezone_string = (string) get_option('timezone_string');
-        if ($timezone_string) {
-            try {
-                $timezone = new DateTimeZone($timezone_string);
-                return $timezone->getOffset(new DateTime()); //in WordPress DateTime defaults to UTC
-            } catch (Exception $e) {
-            }
-        }
-        $offset = get_option('gmt_offset');
-        return (int) ($offset * HOUR_IN_SECONDS);
-    }
-
-
-    /**
-     * Depending on PHP version,
-     * there might not be valid current timezone strings to match these gmt_offsets in its timezone tables.
-     * To get around that, for these fringe timezones we bump them to a known valid offset.
-     * This method should ONLY be called after first verifying an timezone_string cannot be retrieved for the offset.
-     *
-     * @param int $gmt_offset
-     * @return int
-     */
-    public static function adjust_invalid_gmt_offsets($gmt_offset = 0)
-    {
-        //make sure $gmt_offset is int
-        $gmt_offset = (int) $gmt_offset;
-        switch ($gmt_offset) {
-            //-12
-            case -43200:
-                $gmt_offset = -39600;
-                break;
-            //-11.5
-            case -41400:
-                $gmt_offset = -39600;
-                break;
-            //-10.5
-            case -37800:
-                $gmt_offset = -39600;
-                break;
-            //-9.5
-            case -34200:
-                $gmt_offset = -32400;
-                break;
-            //-8.5
-            case -30600:
-                $gmt_offset = -28800;
-                break;
-            //-7.5
-            case -27000:
-                $gmt_offset = -25200;
-                break;
-            //-6.5
-            case -23400:
-                $gmt_offset = -21600;
-                break;
-            //-5.5
-            case -19800:
-                $gmt_offset = -18000;
-                break;
-            //-4.5
-            case -16200:
-                $gmt_offset = -14400;
-                break;
-            //-3.5
-            case -12600:
-                $gmt_offset = -10800;
-                break;
-            //-2.5
-            case -9000:
-                $gmt_offset = -7200;
-                break;
-            //-1.5
-            case -5400:
-                $gmt_offset = -7200;
-                break;
-            //-1
-            case -3600:
-                $gmt_offset = 0;
-                break;
-            //-0.5
-            case -1800:
-                $gmt_offset = 0;
-                break;
-            //.5
-            case 1800:
-                $gmt_offset = 3600;
-                break;
-            //1.5
-            case 5400:
-                $gmt_offset = 7200;
-                break;
-            //2.5
-            case 9000:
-                $gmt_offset = 10800;
-                break;
-            //3.5
-            case 12600:
-                $gmt_offset = 14400;
-                break;
-            //7.5
-            case 27000:
-                $gmt_offset = 28800;
-                break;
-            //8.5
-            case 30600:
-                $gmt_offset = 31500;
-                break;
-            //10.5
-            case 37800:
-                $gmt_offset = 39600;
-                break;
-            //11.5
-            case 41400:
-                $gmt_offset = 43200;
-                break;
-            //12.75
-            case 45900:
-                $gmt_offset = 46800;
-                break;
-            //13.75
-            case 49500:
-                $gmt_offset = 50400;
-                break;
-        }
-        return $gmt_offset;
-    }
-
-
-    /**
-     * get_timezone_string_from_abbreviations_list
-     *
-     * @param int  $gmt_offset
-     * @param bool $coerce If true, we attempt to coerce with our adjustment table @see self::adjust_invalid_gmt_offset.
-     * @return string
-     * @throws EE_Error
-     */
-    public static function get_timezone_string_from_abbreviations_list($gmt_offset = 0, $coerce = true)
-    {
-        $gmt_offset =  (int) $gmt_offset;
-        /** @var array[] $abbreviations */
-        $abbreviations = DateTimeZone::listAbbreviations();
-        foreach ($abbreviations as $abbreviation) {
-            foreach ($abbreviation as $timezone) {
-                if ((int) $timezone['offset'] === $gmt_offset && (bool) $timezone['dst'] === false) {
-                    try {
-                        $offset = self::get_timezone_offset(new DateTimeZone($timezone['timezone_id']));
-                        if ($offset !== $gmt_offset) {
-                            continue;
-                        }
-                        return $timezone['timezone_id'];
-                    } catch (Exception $e) {
-                        continue;
-                    }
-                }
-            }
-        }
-        //if $coerce is true, let's see if we can get a timezone string after the offset is adjusted
-        if ($coerce === true) {
-            $timezone_string = self::get_timezone_string_from_abbreviations_list(
-                self::adjust_invalid_gmt_offsets($gmt_offset),
-                false
-            );
-            if ($timezone_string) {
-                return $timezone_string;
-            }
-        }
-        throw new EE_Error(
-            sprintf(
-                esc_html__(
-                    'The provided GMT offset (%1$s), is invalid, please check with %2$sthis list%3$s for what valid timezones can be used',
-                    'event_espresso'
-                ),
-                $gmt_offset / HOUR_IN_SECONDS,
-                '<a href="http://www.php.net/manual/en/timezones.php">',
-                '</a>'
-            )
-        );
-    }
-
-
-
-    /**
-     * Get Timezone Transitions
-     *
-     * @param DateTimeZone $date_time_zone
-     * @param int|null     $time
-     * @param bool         $first_only
-     * @return array|mixed
-     */
-    public static function get_timezone_transitions(DateTimeZone $date_time_zone, $time = null, $first_only = true)
-    {
-        $time        = is_int($time) || $time === null ? $time : (int) strtotime($time);
-        $time        = preg_match(EE_Datetime_Field::unix_timestamp_regex, $time) ? $time : time();
-        $transitions = $date_time_zone->getTransitions($time);
-        return $first_only && ! isset($transitions['ts']) ? reset($transitions) : $transitions;
-    }
-
-
-    /**
-     * Get Timezone Offset for given timezone object.
-     *
-     * @param DateTimeZone $date_time_zone
-     * @param null         $time
-     * @return mixed
-     * @throws DomainException
-     */
-    public static function get_timezone_offset(DateTimeZone $date_time_zone, $time = null)
-    {
-        $transition = self::get_timezone_transitions($date_time_zone, $time);
-        if (! isset($transition['offset'])) {
-            throw new DomainException(
-                sprintf(
-                    esc_html__('An invalid timezone transition was received %1$s', 'event_espresso'),
-                    print_r($transition, true)
-                )
-            );
-        }
-        return $transition['offset'];
-    }
-
-
-    /**
-     * @param string $timezone_string
-     * @throws EE_Error
-     */
-    public static function timezone_select_input($timezone_string = '')
-    {
-        // get WP date time format
-        $datetime_format = get_option('date_format') . ' ' . get_option('time_format');
-        // if passed a value, then use that, else get WP option
-        $timezone_string = ! empty($timezone_string) ? $timezone_string : (string) get_option('timezone_string');
-        // check if the timezone is valid but don't throw any errors if it isn't
-        $timezone_string = EEH_DTT_Helper::validate_timezone($timezone_string, false)
-            ? $timezone_string
-            : '';
-        $gmt_offset      = get_option('gmt_offset');
-        $check_zone_info = true;
-        if (empty($timezone_string)) {
-            // Create a UTC+- zone if no timezone string exists
-            $timezone_string = 'UTC';
-            $check_zone_info = false;
-            if ($gmt_offset > 0) {
-                $timezone_string = 'UTC+' . $gmt_offset;
-            } elseif ($gmt_offset < 0) {
-                $timezone_string = 'UTC' . $gmt_offset;
-            }
-        }
-        ?>
+	/**
+	 * return the timezone set for the WP install
+	 *
+	 * @return string valid timezone string for PHP DateTimeZone() class
+	 * @throws EE_Error
+	 */
+	public static function get_timezone()
+	{
+		return EEH_DTT_Helper::get_valid_timezone_string();
+	}
+
+
+	/**
+	 * get_valid_timezone_string
+	 *    ensures that a valid timezone string is returned
+	 *
+	 * @param string $timezone_string
+	 * @return string
+	 * @throws EE_Error
+	 */
+	public static function get_valid_timezone_string($timezone_string = '')
+	{
+		// if passed a value, then use that, else get WP option
+		$timezone_string = ! empty($timezone_string) ? $timezone_string : (string) get_option('timezone_string');
+		// value from above exists, use that, else get timezone string from gmt_offset
+		$timezone_string = ! empty($timezone_string)
+			? $timezone_string
+			: EEH_DTT_Helper::get_timezone_string_from_gmt_offset();
+		EEH_DTT_Helper::validate_timezone($timezone_string);
+		return $timezone_string;
+	}
+
+
+	/**
+	 * This only purpose for this static method is to validate that the incoming timezone is a valid php timezone.
+	 *
+	 * @static
+	 * @param  string $timezone_string Timezone string to check
+	 * @param bool    $throw_error
+	 * @return bool
+	 * @throws EE_Error
+	 */
+	public static function validate_timezone($timezone_string, $throw_error = true)
+	{
+		// easiest way to test a timezone string is just see if it throws an error when you try to create a DateTimeZone object with it
+		try {
+			new DateTimeZone($timezone_string);
+		} catch (Exception $e) {
+			// sometimes we take exception to exceptions
+			if (! $throw_error) {
+				return false;
+			}
+			throw new EE_Error(
+				sprintf(
+					esc_html__(
+						'The timezone given (%1$s), is invalid, please check with %2$sthis list%3$s for what valid timezones can be used',
+						'event_espresso'
+					),
+					$timezone_string,
+					'<a href="http://www.php.net/manual/en/timezones.php">',
+					'</a>'
+				)
+			);
+		}
+		return true;
+	}
+
+
+	/**
+	 * _create_timezone_object_from_timezone_name
+	 *
+	 * @param float|string $gmt_offset
+	 * @return string
+	 * @throws EE_Error
+	 */
+	public static function get_timezone_string_from_gmt_offset($gmt_offset = '')
+	{
+		$timezone_string = 'UTC';
+		//if there is no incoming gmt_offset, then because WP hooks in on timezone_string, we need to see if that is
+		//set because it will override `gmt_offset` via `pre_get_option` filter.  If that's set, then let's just use
+		//that!  Otherwise we'll leave timezone_string at the default of 'UTC' before doing other logic.
+		if ($gmt_offset === '') {
+			//autoloaded so no need to set to a variable.  There will not be multiple hits to the db.
+			if (get_option('timezone_string')) {
+				return (string) get_option('timezone_string');
+			}
+		}
+		$gmt_offset = $gmt_offset !== '' ? $gmt_offset : (string) get_option('gmt_offset');
+		$gmt_offset = (float) $gmt_offset;
+		//if $gmt_offset is 0, then just return UTC
+		if ($gmt_offset === (float) 0) {
+			return $timezone_string;
+		}
+		if ($gmt_offset !== '') {
+			// convert GMT offset to seconds
+			$gmt_offset *= HOUR_IN_SECONDS;
+			// although we don't know the TZ abbreviation, we know the UTC offset
+			$timezone_string = timezone_name_from_abbr(null, $gmt_offset);
+			//only use this timezone_string IF it's current offset matches the given offset
+			if(! empty($timezone_string)) {
+				$offset  = null;
+				try {
+					$offset = self::get_timezone_offset(new DateTimeZone($timezone_string));
+					if ($offset !== $gmt_offset) {
+						$timezone_string = false;
+					}
+				} catch (Exception $e) {
+					$timezone_string = false;
+				}
+			}
+		}
+		// better have a valid timezone string by now, but if not, sigh... loop thru  the timezone_abbreviations_list()...
+		$timezone_string = $timezone_string !== false
+			? $timezone_string
+			: EEH_DTT_Helper::get_timezone_string_from_abbreviations_list($gmt_offset);
+		return $timezone_string;
+	}
+
+
+	/**
+	 * Gets the site's GMT offset based on either the timezone string
+	 * (in which case teh gmt offset will vary depending on the location's
+	 * observance of daylight savings time) or the gmt_offset wp option
+	 *
+	 * @return int seconds offset
+	 */
+	public static function get_site_timezone_gmt_offset()
+	{
+		$timezone_string = (string) get_option('timezone_string');
+		if ($timezone_string) {
+			try {
+				$timezone = new DateTimeZone($timezone_string);
+				return $timezone->getOffset(new DateTime()); //in WordPress DateTime defaults to UTC
+			} catch (Exception $e) {
+			}
+		}
+		$offset = get_option('gmt_offset');
+		return (int) ($offset * HOUR_IN_SECONDS);
+	}
+
+
+	/**
+	 * Depending on PHP version,
+	 * there might not be valid current timezone strings to match these gmt_offsets in its timezone tables.
+	 * To get around that, for these fringe timezones we bump them to a known valid offset.
+	 * This method should ONLY be called after first verifying an timezone_string cannot be retrieved for the offset.
+	 *
+	 * @param int $gmt_offset
+	 * @return int
+	 */
+	public static function adjust_invalid_gmt_offsets($gmt_offset = 0)
+	{
+		//make sure $gmt_offset is int
+		$gmt_offset = (int) $gmt_offset;
+		switch ($gmt_offset) {
+			//-12
+			case -43200:
+				$gmt_offset = -39600;
+				break;
+			//-11.5
+			case -41400:
+				$gmt_offset = -39600;
+				break;
+			//-10.5
+			case -37800:
+				$gmt_offset = -39600;
+				break;
+			//-9.5
+			case -34200:
+				$gmt_offset = -32400;
+				break;
+			//-8.5
+			case -30600:
+				$gmt_offset = -28800;
+				break;
+			//-7.5
+			case -27000:
+				$gmt_offset = -25200;
+				break;
+			//-6.5
+			case -23400:
+				$gmt_offset = -21600;
+				break;
+			//-5.5
+			case -19800:
+				$gmt_offset = -18000;
+				break;
+			//-4.5
+			case -16200:
+				$gmt_offset = -14400;
+				break;
+			//-3.5
+			case -12600:
+				$gmt_offset = -10800;
+				break;
+			//-2.5
+			case -9000:
+				$gmt_offset = -7200;
+				break;
+			//-1.5
+			case -5400:
+				$gmt_offset = -7200;
+				break;
+			//-1
+			case -3600:
+				$gmt_offset = 0;
+				break;
+			//-0.5
+			case -1800:
+				$gmt_offset = 0;
+				break;
+			//.5
+			case 1800:
+				$gmt_offset = 3600;
+				break;
+			//1.5
+			case 5400:
+				$gmt_offset = 7200;
+				break;
+			//2.5
+			case 9000:
+				$gmt_offset = 10800;
+				break;
+			//3.5
+			case 12600:
+				$gmt_offset = 14400;
+				break;
+			//7.5
+			case 27000:
+				$gmt_offset = 28800;
+				break;
+			//8.5
+			case 30600:
+				$gmt_offset = 31500;
+				break;
+			//10.5
+			case 37800:
+				$gmt_offset = 39600;
+				break;
+			//11.5
+			case 41400:
+				$gmt_offset = 43200;
+				break;
+			//12.75
+			case 45900:
+				$gmt_offset = 46800;
+				break;
+			//13.75
+			case 49500:
+				$gmt_offset = 50400;
+				break;
+		}
+		return $gmt_offset;
+	}
+
+
+	/**
+	 * get_timezone_string_from_abbreviations_list
+	 *
+	 * @param int  $gmt_offset
+	 * @param bool $coerce If true, we attempt to coerce with our adjustment table @see self::adjust_invalid_gmt_offset.
+	 * @return string
+	 * @throws EE_Error
+	 */
+	public static function get_timezone_string_from_abbreviations_list($gmt_offset = 0, $coerce = true)
+	{
+		$gmt_offset =  (int) $gmt_offset;
+		/** @var array[] $abbreviations */
+		$abbreviations = DateTimeZone::listAbbreviations();
+		foreach ($abbreviations as $abbreviation) {
+			foreach ($abbreviation as $timezone) {
+				if ((int) $timezone['offset'] === $gmt_offset && (bool) $timezone['dst'] === false) {
+					try {
+						$offset = self::get_timezone_offset(new DateTimeZone($timezone['timezone_id']));
+						if ($offset !== $gmt_offset) {
+							continue;
+						}
+						return $timezone['timezone_id'];
+					} catch (Exception $e) {
+						continue;
+					}
+				}
+			}
+		}
+		//if $coerce is true, let's see if we can get a timezone string after the offset is adjusted
+		if ($coerce === true) {
+			$timezone_string = self::get_timezone_string_from_abbreviations_list(
+				self::adjust_invalid_gmt_offsets($gmt_offset),
+				false
+			);
+			if ($timezone_string) {
+				return $timezone_string;
+			}
+		}
+		throw new EE_Error(
+			sprintf(
+				esc_html__(
+					'The provided GMT offset (%1$s), is invalid, please check with %2$sthis list%3$s for what valid timezones can be used',
+					'event_espresso'
+				),
+				$gmt_offset / HOUR_IN_SECONDS,
+				'<a href="http://www.php.net/manual/en/timezones.php">',
+				'</a>'
+			)
+		);
+	}
+
+
+
+	/**
+	 * Get Timezone Transitions
+	 *
+	 * @param DateTimeZone $date_time_zone
+	 * @param int|null     $time
+	 * @param bool         $first_only
+	 * @return array|mixed
+	 */
+	public static function get_timezone_transitions(DateTimeZone $date_time_zone, $time = null, $first_only = true)
+	{
+		$time        = is_int($time) || $time === null ? $time : (int) strtotime($time);
+		$time        = preg_match(EE_Datetime_Field::unix_timestamp_regex, $time) ? $time : time();
+		$transitions = $date_time_zone->getTransitions($time);
+		return $first_only && ! isset($transitions['ts']) ? reset($transitions) : $transitions;
+	}
+
+
+	/**
+	 * Get Timezone Offset for given timezone object.
+	 *
+	 * @param DateTimeZone $date_time_zone
+	 * @param null         $time
+	 * @return mixed
+	 * @throws DomainException
+	 */
+	public static function get_timezone_offset(DateTimeZone $date_time_zone, $time = null)
+	{
+		$transition = self::get_timezone_transitions($date_time_zone, $time);
+		if (! isset($transition['offset'])) {
+			throw new DomainException(
+				sprintf(
+					esc_html__('An invalid timezone transition was received %1$s', 'event_espresso'),
+					print_r($transition, true)
+				)
+			);
+		}
+		return $transition['offset'];
+	}
+
+
+	/**
+	 * @param string $timezone_string
+	 * @throws EE_Error
+	 */
+	public static function timezone_select_input($timezone_string = '')
+	{
+		// get WP date time format
+		$datetime_format = get_option('date_format') . ' ' . get_option('time_format');
+		// if passed a value, then use that, else get WP option
+		$timezone_string = ! empty($timezone_string) ? $timezone_string : (string) get_option('timezone_string');
+		// check if the timezone is valid but don't throw any errors if it isn't
+		$timezone_string = EEH_DTT_Helper::validate_timezone($timezone_string, false)
+			? $timezone_string
+			: '';
+		$gmt_offset      = get_option('gmt_offset');
+		$check_zone_info = true;
+		if (empty($timezone_string)) {
+			// Create a UTC+- zone if no timezone string exists
+			$timezone_string = 'UTC';
+			$check_zone_info = false;
+			if ($gmt_offset > 0) {
+				$timezone_string = 'UTC+' . $gmt_offset;
+			} elseif ($gmt_offset < 0) {
+				$timezone_string = 'UTC' . $gmt_offset;
+			}
+		}
+		?>
 
         <p>
             <label for="timezone_string"><?php _e('timezone'); ?></label>
@@ -403,13 +403,13 @@ 
 
         <p>
         <span><?php
-            printf(
-                __('%1$sUTC%2$s time is %3$s'),
-                '<abbr title="Coordinated Universal Time">',
-                '</abbr>',
-                '<code>' . date_i18n($datetime_format, false, true) . '</code>'
-            );
-            ?></span>
+			printf(
+				__('%1$sUTC%2$s time is %3$s'),
+				'<abbr title="Coordinated Universal Time">',
+				'</abbr>',
+				'<code>' . date_i18n($datetime_format, false, true) . '</code>'
+			);
+			?></span>
         <?php if (! empty($timezone_string) || ! empty($gmt_offset)) : ?>
         <br/><span><?php printf(__('Local time is %1$s'), '<code>' . date_i18n($datetime_format) . '</code>'); ?></span>
     <?php endif; ?>
@@ -418,847 +418,847 @@ 
         <br/>
         <span>
 					<?php
-                    // Set TZ so localtime works.
-                    date_default_timezone_set($timezone_string);
-                    $now = localtime(time(), true);
-                    if ($now['tm_isdst']) {
-                        _e('This timezone is currently in daylight saving time.');
-                    } else {
-                        _e('This timezone is currently in standard time.');
-                    }
-                    ?>
+					// Set TZ so localtime works.
+					date_default_timezone_set($timezone_string);
+					$now = localtime(time(), true);
+					if ($now['tm_isdst']) {
+						_e('This timezone is currently in daylight saving time.');
+					} else {
+						_e('This timezone is currently in standard time.');
+					}
+					?>
             <br/>
             <?php
-            if (function_exists('timezone_transitions_get')) {
-                $found                   = false;
-                $date_time_zone_selected = new DateTimeZone($timezone_string);
-                $tz_offset               = timezone_offset_get($date_time_zone_selected, date_create());
-                $right_now               = time();
-                $tr['isdst']             = false;
-                foreach (timezone_transitions_get($date_time_zone_selected) as $tr) {
-                    if ($tr['ts'] > $right_now) {
-                        $found = true;
-                        break;
-                    }
-                }
-                if ($found) {
-                    $message = $tr['isdst']
-                        ?
-                        __(' Daylight saving time begins on: %s.')
-                        :
-                        __(' Standard time begins  on: %s.');
-                    // Add the difference between the current offset and the new offset to ts to get the correct transition time from date_i18n().
-                    printf(
-                        $message,
-                        '<code >' . date_i18n($datetime_format, $tr['ts'] + ($tz_offset - $tr['offset'])) . '</code >'
-                    );
-                } else {
-                    _e('This timezone does not observe daylight saving time.');
-                }
-            }
-            // Set back to UTC.
-            date_default_timezone_set('UTC');
-            ?>
+			if (function_exists('timezone_transitions_get')) {
+				$found                   = false;
+				$date_time_zone_selected = new DateTimeZone($timezone_string);
+				$tz_offset               = timezone_offset_get($date_time_zone_selected, date_create());
+				$right_now               = time();
+				$tr['isdst']             = false;
+				foreach (timezone_transitions_get($date_time_zone_selected) as $tr) {
+					if ($tr['ts'] > $right_now) {
+						$found = true;
+						break;
+					}
+				}
+				if ($found) {
+					$message = $tr['isdst']
+						?
+						__(' Daylight saving time begins on: %s.')
+						:
+						__(' Standard time begins  on: %s.');
+					// Add the difference between the current offset and the new offset to ts to get the correct transition time from date_i18n().
+					printf(
+						$message,
+						'<code >' . date_i18n($datetime_format, $tr['ts'] + ($tz_offset - $tr['offset'])) . '</code >'
+					);
+				} else {
+					_e('This timezone does not observe daylight saving time.');
+				}
+			}
+			// Set back to UTC.
+			date_default_timezone_set('UTC');
+			?>
 				</span></p>
         <?php
-    endif;
-    }
-
-
-    /**
-     * This method will take an incoming unix timestamp and add the offset to it for the given timezone_string.
-     * If no unix timestamp is given then time() is used.  If no timezone is given then the set timezone string for
-     * the site is used.
-     * This is used typically when using a Unix timestamp any core WP functions that expect their specially
-     * computed timestamp (i.e. date_i18n() )
-     *
-     * @param int    $unix_timestamp                  if 0, then time() will be used.
-     * @param string $timezone_string                 timezone_string. If empty, then the current set timezone for the
-     *                                                site will be used.
-     * @return int $unix_timestamp with the offset applied for the given timezone.
-     * @throws EE_Error
-     */
-    public static function get_timestamp_with_offset($unix_timestamp = 0, $timezone_string = '')
-    {
-        $unix_timestamp  = $unix_timestamp === 0 ? time() : (int) $unix_timestamp;
-        $timezone_string = self::get_valid_timezone_string($timezone_string);
-        $TimeZone        = new DateTimeZone($timezone_string);
-        $DateTime        = new DateTime('@' . $unix_timestamp, $TimeZone);
-        $offset          = timezone_offset_get($TimeZone, $DateTime);
-        return (int) $DateTime->format('U') + (int) $offset;
-    }
-
-
-    /**
-     *    _set_date_time_field
-     *    modifies EE_Base_Class EE_Datetime_Field objects
-     *
-     * @param  EE_Base_Class $obj                 EE_Base_Class object
-     * @param    DateTime    $DateTime            PHP DateTime object
-     * @param  string        $datetime_field_name the datetime fieldname to be manipulated
-     * @return EE_Base_Class
-     * @throws EE_Error
-     */
-    protected static function _set_date_time_field(EE_Base_Class $obj, DateTime $DateTime, $datetime_field_name)
-    {
-        // grab current datetime format
-        $current_format = $obj->get_format();
-        // set new full timestamp format
-        $obj->set_date_format(EE_Datetime_Field::mysql_date_format);
-        $obj->set_time_format(EE_Datetime_Field::mysql_time_format);
-        // set the new date value using a full timestamp format so that no data is lost
-        $obj->set($datetime_field_name, $DateTime->format(EE_Datetime_Field::mysql_timestamp_format));
-        // reset datetime formats
-        $obj->set_date_format($current_format[0]);
-        $obj->set_time_format($current_format[1]);
-        return $obj;
-    }
-
-
-    /**
-     *    date_time_add
-     *    helper for doing simple datetime calculations on a given datetime from EE_Base_Class
-     *    and modifying it IN the EE_Base_Class so you don't have to do anything else.
-     *
-     * @param  EE_Base_Class $obj                 EE_Base_Class object
-     * @param  string        $datetime_field_name name of the EE_Datetime_Filed datatype db column to be manipulated
-     * @param  string        $period              what you are adding. The options are (years, months, days, hours,
-     *                                            minutes, seconds) defaults to years
-     * @param  integer       $value               what you want to increment the time by
-     * @return EE_Base_Class return the EE_Base_Class object so right away you can do something with it
-     *                                            (chaining)
-     * @throws EE_Error
-     * @throws Exception
-     */
-    public static function date_time_add(EE_Base_Class $obj, $datetime_field_name, $period = 'years', $value = 1)
-    {
-        //get the raw UTC date.
-        $DateTime = $obj->get_DateTime_object($datetime_field_name);
-        $DateTime = EEH_DTT_Helper::calc_date($DateTime, $period, $value);
-        return EEH_DTT_Helper::_set_date_time_field($obj, $DateTime, $datetime_field_name);
-    }
-
-
-    /**
-     *    date_time_subtract
-     *    same as date_time_add except subtracting value instead of adding.
-     *
-     * @param EE_Base_Class $obj
-     * @param  string       $datetime_field_name name of the EE_Datetime_Filed datatype db column to be manipulated
-     * @param string        $period
-     * @param int           $value
-     * @return EE_Base_Class
-     * @throws EE_Error
-     * @throws Exception
-     */
-    public static function date_time_subtract(EE_Base_Class $obj, $datetime_field_name, $period = 'years', $value = 1)
-    {
-        //get the raw UTC date
-        $DateTime = $obj->get_DateTime_object($datetime_field_name);
-        $DateTime = EEH_DTT_Helper::calc_date($DateTime, $period, $value, '-');
-        return EEH_DTT_Helper::_set_date_time_field($obj, $DateTime, $datetime_field_name);
-    }
-
-
-    /**
-     * Simply takes an incoming DateTime object and does calculations on it based on the incoming parameters
-     *
-     * @param  DateTime   $DateTime DateTime object
-     * @param  string     $period   a value to indicate what interval is being used in the calculation. The options are
-     *                              'years', 'months', 'days', 'hours', 'minutes', 'seconds'. Defaults to years.
-     * @param  int|string $value    What you want to increment the date by
-     * @param  string     $operand  What operand you wish to use for the calculation
-     * @return DateTime return whatever type came in.
-     * @throws Exception
-     * @throws EE_Error
-     */
-    protected static function _modify_datetime_object(DateTime $DateTime, $period = 'years', $value = 1, $operand = '+')
-    {
-        if (! $DateTime instanceof DateTime) {
-            throw new EE_Error(
-                sprintf(
-                    esc_html__('Expected a PHP DateTime object, but instead received %1$s', 'event_espresso'),
-                    print_r($DateTime, true)
-                )
-            );
-        }
-        switch ($period) {
-            case 'years' :
-                $value = 'P' . $value . 'Y';
-                break;
-            case 'months' :
-                $value = 'P' . $value . 'M';
-                break;
-            case 'weeks' :
-                $value = 'P' . $value . 'W';
-                break;
-            case 'days' :
-                $value = 'P' . $value . 'D';
-                break;
-            case 'hours' :
-                $value = 'PT' . $value . 'H';
-                break;
-            case 'minutes' :
-                $value = 'PT' . $value . 'M';
-                break;
-            case 'seconds' :
-                $value = 'PT' . $value . 'S';
-                break;
-        }
-        switch ($operand) {
-            case '+':
-                $DateTime->add(new DateInterval($value));
-                break;
-            case '-':
-                $DateTime->sub(new DateInterval($value));
-                break;
-        }
-        return $DateTime;
-    }
-
-
-    /**
-     * Simply takes an incoming Unix timestamp and does calculations on it based on the incoming parameters
-     *
-     * @param  int     $timestamp Unix timestamp
-     * @param  string  $period    a value to indicate what interval is being used in the calculation. The options are
-     *                            'years', 'months', 'days', 'hours', 'minutes', 'seconds'. Defaults to years.
-     * @param  integer $value     What you want to increment the date by
-     * @param  string  $operand   What operand you wish to use for the calculation
-     * @return int
-     * @throws EE_Error
-     */
-    protected static function _modify_timestamp($timestamp, $period = 'years', $value = 1, $operand = '+')
-    {
-        if (! preg_match(EE_Datetime_Field::unix_timestamp_regex, $timestamp)) {
-            throw new EE_Error(
-                sprintf(
-                    esc_html__('Expected a Unix timestamp, but instead received %1$s', 'event_espresso'),
-                    print_r($timestamp, true)
-                )
-            );
-        }
-        switch ($period) {
-            case 'years' :
-                $value = YEAR_IN_SECONDS * $value;
-                break;
-            case 'months' :
-                $value = YEAR_IN_SECONDS / 12 * $value;
-                break;
-            case 'weeks' :
-                $value = WEEK_IN_SECONDS * $value;
-                break;
-            case 'days' :
-                $value = DAY_IN_SECONDS * $value;
-                break;
-            case 'hours' :
-                $value = HOUR_IN_SECONDS * $value;
-                break;
-            case 'minutes' :
-                $value = MINUTE_IN_SECONDS * $value;
-                break;
-        }
-        switch ($operand) {
-            case '+':
-                $timestamp += $value;
-                break;
-            case '-':
-                $timestamp -= $value;
-                break;
-        }
-        return $timestamp;
-    }
-
-
-    /**
-     * Simply takes an incoming UTC timestamp or DateTime object and does calculations on it based on the incoming
-     * parameters and returns the new timestamp or DateTime.
-     *
-     * @param  int | DateTime $DateTime_or_timestamp DateTime object or Unix timestamp
-     * @param  string         $period                a value to indicate what interval is being used in the
-     *                                               calculation. The options are 'years', 'months', 'days', 'hours',
-     *                                               'minutes', 'seconds'. Defaults to years.
-     * @param  integer        $value                 What you want to increment the date by
-     * @param  string         $operand               What operand you wish to use for the calculation
-     * @return mixed string|DateTime          return whatever type came in.
-     * @throws Exception
-     * @throws EE_Error
-     */
-    public static function calc_date($DateTime_or_timestamp, $period = 'years', $value = 1, $operand = '+')
-    {
-        if ($DateTime_or_timestamp instanceof DateTime) {
-            return EEH_DTT_Helper::_modify_datetime_object(
-                $DateTime_or_timestamp,
-                $period,
-                $value,
-                $operand
-            );
-        }
-        if (preg_match(EE_Datetime_Field::unix_timestamp_regex, $DateTime_or_timestamp)) {
-            return EEH_DTT_Helper::_modify_timestamp(
-                $DateTime_or_timestamp,
-                $period,
-                $value,
-                $operand
-            );
-        }
-        //error
-        return $DateTime_or_timestamp;
-    }
-
-
-    /**
-     * The purpose of this helper method is to receive an incoming format string in php date/time format
-     * and spit out the js and moment.js equivalent formats.
-     * Note, if no format string is given, then it is assumed the user wants what is set for WP.
-     * Note, js date and time formats are those used by the jquery-ui datepicker and the jquery-ui date-
-     * time picker.
-     *
-     * @see http://stackoverflow.com/posts/16725290/ for the code inspiration.
-     * @param string $date_format_string
-     * @param string $time_format_string
-     * @return array
-     *              array(
-     *              'js' => array (
-     *              'date' => //date format
-     *              'time' => //time format
-     *              ),
-     *              'moment' => //date and time format.
-     *              )
-     */
-    public static function convert_php_to_js_and_moment_date_formats(
-        $date_format_string = null,
-        $time_format_string = null
-    ) {
-        if ($date_format_string === null) {
-            $date_format_string = (string) get_option('date_format');
-        }
-        if ($time_format_string === null) {
-            $time_format_string = (string) get_option('time_format');
-        }
-        $date_format = self::_php_to_js_moment_converter($date_format_string);
-        $time_format = self::_php_to_js_moment_converter($time_format_string);
-        return array(
-            'js'     => array(
-                'date' => $date_format['js'],
-                'time' => $time_format['js'],
-            ),
-            'moment' => $date_format['moment'] . ' ' . $time_format['moment'],
-        );
-    }
-
-
-    /**
-     * This converts incoming format string into js and moment variations.
-     *
-     * @param string $format_string incoming php format string
-     * @return array js and moment formats.
-     */
-    protected static function _php_to_js_moment_converter($format_string)
-    {
-        /**
-         * This is a map of symbols for formats.
-         * The index is the php symbol, the equivalent values are in the array.
-         *
-         * @var array
-         */
-        $symbols_map          = array(
-            // Day
-            //01
-            'd' => array(
-                'js'     => 'dd',
-                'moment' => 'DD',
-            ),
-            //Mon
-            'D' => array(
-                'js'     => 'D',
-                'moment' => 'ddd',
-            ),
-            //1,2,...31
-            'j' => array(
-                'js'     => 'd',
-                'moment' => 'D',
-            ),
-            //Monday
-            'l' => array(
-                'js'     => 'DD',
-                'moment' => 'dddd',
-            ),
-            //ISO numeric representation of the day of the week (1-6)
-            'N' => array(
-                'js'     => '',
-                'moment' => 'E',
-            ),
-            //st,nd.rd
-            'S' => array(
-                'js'     => '',
-                'moment' => 'o',
-            ),
-            //numeric representation of day of week (0-6)
-            'w' => array(
-                'js'     => '',
-                'moment' => 'd',
-            ),
-            //day of year starting from 0 (0-365)
-            'z' => array(
-                'js'     => 'o',
-                'moment' => 'DDD' //note moment does not start with 0 so will need to modify by subtracting 1
-            ),
-            // Week
-            //ISO-8601 week number of year (weeks starting on monday)
-            'W' => array(
-                'js'     => '',
-                'moment' => 'w',
-            ),
-            // Month
-            // January...December
-            'F' => array(
-                'js'     => 'MM',
-                'moment' => 'MMMM',
-            ),
-            //01...12
-            'm' => array(
-                'js'     => 'mm',
-                'moment' => 'MM',
-            ),
-            //Jan...Dec
-            'M' => array(
-                'js'     => 'M',
-                'moment' => 'MMM',
-            ),
-            //1-12
-            'n' => array(
-                'js'     => 'm',
-                'moment' => 'M',
-            ),
-            //number of days in given month
-            't' => array(
-                'js'     => '',
-                'moment' => '',
-            ),
-            // Year
-            //whether leap year or not 1/0
-            'L' => array(
-                'js'     => '',
-                'moment' => '',
-            ),
-            //ISO-8601 year number
-            'o' => array(
-                'js'     => '',
-                'moment' => 'GGGG',
-            ),
-            //1999...2003
-            'Y' => array(
-                'js'     => 'yy',
-                'moment' => 'YYYY',
-            ),
-            //99...03
-            'y' => array(
-                'js'     => 'y',
-                'moment' => 'YY',
-            ),
-            // Time
-            // am/pm
-            'a' => array(
-                'js'     => 'tt',
-                'moment' => 'a',
-            ),
-            // AM/PM
-            'A' => array(
-                'js'     => 'TT',
-                'moment' => 'A',
-            ),
-            // Swatch Internet Time?!?
-            'B' => array(
-                'js'     => '',
-                'moment' => '',
-            ),
-            //1...12
-            'g' => array(
-                'js'     => 'h',
-                'moment' => 'h',
-            ),
-            //0...23
-            'G' => array(
-                'js'     => 'H',
-                'moment' => 'H',
-            ),
-            //01...12
-            'h' => array(
-                'js'     => 'hh',
-                'moment' => 'hh',
-            ),
-            //00...23
-            'H' => array(
-                'js'     => 'HH',
-                'moment' => 'HH',
-            ),
-            //00..59
-            'i' => array(
-                'js'     => 'mm',
-                'moment' => 'mm',
-            ),
-            //seconds... 00...59
-            's' => array(
-                'js'     => 'ss',
-                'moment' => 'ss',
-            ),
-            //microseconds
-            'u' => array(
-                'js'     => '',
-                'moment' => '',
-            ),
-        );
-        $jquery_ui_format     = '';
-        $moment_format        = '';
-        $escaping             = false;
-        $format_string_length = strlen($format_string);
-        for ($i = 0; $i < $format_string_length; $i++) {
-            $char = $format_string[ $i ];
-            if ($char === '\\') { // PHP date format escaping character
-                $i++;
-                if ($escaping) {
-                    $jquery_ui_format .= $format_string[ $i ];
-                    $moment_format    .= $format_string[ $i ];
-                } else {
-                    $jquery_ui_format .= '\'' . $format_string[ $i ];
-                    $moment_format    .= $format_string[ $i ];
-                }
-                $escaping = true;
-            } else {
-                if ($escaping) {
-                    $jquery_ui_format .= "'";
-                    $moment_format    .= "'";
-                    $escaping         = false;
-                }
-                if (isset($symbols_map[ $char ])) {
-                    $jquery_ui_format .= $symbols_map[ $char ]['js'];
-                    $moment_format    .= $symbols_map[ $char ]['moment'];
-                } else {
-                    $jquery_ui_format .= $char;
-                    $moment_format    .= $char;
-                }
-            }
-        }
-        return array('js' => $jquery_ui_format, 'moment' => $moment_format);
-    }
-
-
-    /**
-     * This takes an incoming format string and validates it to ensure it will work fine with PHP.
-     *
-     * @param string $format_string   Incoming format string for php date().
-     * @return mixed bool|array  If all is okay then TRUE is returned.  Otherwise an array of validation
-     *                                errors is returned.  So for client code calling, check for is_array() to
-     *                                indicate failed validations.
-     */
-    public static function validate_format_string($format_string)
-    {
-        $error_msg = array();
-        //time format checks
-        switch (true) {
-            case   strpos($format_string, 'h') !== false  :
-            case   strpos($format_string, 'g') !== false :
-                /**
-                 * if the time string has a lowercase 'h' which == 12 hour time format and there
-                 * is not any ante meridiem format ('a' or 'A').  Then throw an error because its
-                 * too ambiguous and PHP won't be able to figure out whether 1 = 1pm or 1am.
-                 */
-                if (stripos($format_string, 'A') === false) {
-                    $error_msg[] = esc_html__(
-                        'There is a  time format for 12 hour time but no  "a" or "A" to indicate am/pm.  Without this distinction, PHP is unable to determine if a "1" for the hour value equals "1pm" or "1am".',
-                        'event_espresso'
-                    );
-                }
-                break;
-        }
-        return empty($error_msg) ? true : $error_msg;
-    }
-
-
-    /**
-     *     If the the first date starts at midnight on one day, and the next date ends at midnight on the
-     *     very next day then this method will return true.
-     *    If $date_1 = 2015-12-15 00:00:00 and $date_2 = 2015-12-16 00:00:00 then this function will return true.
-     *    If $date_1 = 2015-12-15 03:00:00 and $date_2 = 2015-12_16 03:00:00 then this function will return false.
-     *    If $date_1 = 2015-12-15 00:00:00 and $date_2 = 2015-12-15 00:00:00 then this function will return true.
-     *
-     * @param mixed $date_1
-     * @param mixed $date_2
-     * @return bool
-     */
-    public static function dates_represent_one_24_hour_date($date_1, $date_2)
-    {
-
-        if (
-            (! $date_1 instanceof DateTime || ! $date_2 instanceof DateTime)
-            || ($date_1->format(EE_Datetime_Field::mysql_time_format) !== '00:00:00'
-                || $date_2->format(
-                    EE_Datetime_Field::mysql_time_format
-                ) !== '00:00:00')
-        ) {
-            return false;
-        }
-        return $date_2->format('U') - $date_1->format('U') === 86400;
-    }
-
-
-    /**
-     * This returns the appropriate query interval string that can be used in sql queries involving mysql Date
-     * Functions.
-     *
-     * @param string $timezone_string    A timezone string in a valid format to instantiate a DateTimeZone object.
-     * @param string $field_for_interval The Database field that is the interval is applied to in the query.
-     * @return string
-     */
-    public static function get_sql_query_interval_for_offset($timezone_string, $field_for_interval)
-    {
-        try {
-            /** need to account for timezone offset on the selects */
-            $DateTimeZone = new DateTimeZone($timezone_string);
-        } catch (Exception $e) {
-            $DateTimeZone = null;
-        }
-        /**
-         * Note get_option( 'gmt_offset') returns a value in hours, whereas DateTimeZone::getOffset returns values in seconds.
-         * Hence we do the calc for DateTimeZone::getOffset.
-         */
-        $offset         = $DateTimeZone instanceof DateTimeZone
-            ? $DateTimeZone->getOffset(new DateTime('now')) / HOUR_IN_SECONDS
-            : (float) get_option('gmt_offset');
-        $query_interval = $offset < 0
-            ? 'DATE_SUB(' . $field_for_interval . ', INTERVAL ' . $offset * -1 . ' HOUR)'
-            : 'DATE_ADD(' . $field_for_interval . ', INTERVAL ' . $offset . ' HOUR)';
-        return $query_interval;
-    }
-
-
-    /**
-     * Retrieves the site's default timezone and returns it formatted so it's ready for display
-     * to users. If you want to customize how its displayed feel free to fetch the 'timezone_string'
-     * and 'gmt_offset' WordPress options directly; or use the filter
-     * FHEE__EEH_DTT_Helper__get_timezone_string_for_display
-     * (although note that we remove any HTML that may be added)
-     *
-     * @return string
-     */
-    public static function get_timezone_string_for_display()
-    {
-        $pretty_timezone = apply_filters('FHEE__EEH_DTT_Helper__get_timezone_string_for_display', '');
-        if (! empty($pretty_timezone)) {
-            return esc_html($pretty_timezone);
-        }
-        $timezone_string = get_option('timezone_string');
-        if ($timezone_string) {
-            static $mo_loaded = false;
-            // Load translations for continents and cities just like wp_timezone_choice does
-            if (! $mo_loaded) {
-                $locale = get_locale();
-                $mofile = WP_LANG_DIR . '/continents-cities-' . $locale . '.mo';
-                load_textdomain('continents-cities', $mofile);
-                $mo_loaded = true;
-            }
-            //well that was easy.
-            $parts = explode('/', $timezone_string);
-            //remove the continent
-            unset($parts[0]);
-            $t_parts = array();
-            foreach ($parts as $part) {
-                $t_parts[] = translate(str_replace('_', ' ', $part), 'continents-cities');
-            }
-            return implode(' - ', $t_parts);
-        }
-        //they haven't set the timezone string, so let's return a string like "UTC+1"
-        $gmt_offset = get_option('gmt_offset');
-        $prefix     = (int) $gmt_offset >= 0 ? '+' : '';
-        $parts      = explode('.', (string) $gmt_offset);
-        if (count($parts) === 1) {
-            $parts[1] = '00';
-        } else {
-            //convert the part after the decimal, eg "5" (from x.5) or "25" (from x.25)
-            //to minutes, eg 30 or 15, respectively
-            $hour_fraction = (float) ('0.' . $parts[1]);
-            $parts[1]      = (string) $hour_fraction * 60;
-        }
-        return sprintf(__('UTC%1$s', 'event_espresso'), $prefix . implode(':', $parts));
-    }
-
-
-
-    /**
-     * So PHP does this awesome thing where if you are trying to get a timestamp
-     * for a month using a string like "February" or "February 2017",
-     * and you don't specify a day as part of your string,
-     * then PHP will use whatever the current day of the month is.
-     * IF the current day of the month happens to be the 30th or 31st,
-     * then PHP gets really confused by a date like February 30,
-     * so instead of saying
-     *      "Hey February only has 28 days (this year)...
-     *      ...you must have meant the last day of the month!"
-     * PHP does the next most logical thing, and bumps the date up to March 2nd,
-     * because someone requesting February 30th obviously meant March 1st!
-     * The way around this is to always set the day to the first,
-     * so that the month will stay on the month you wanted.
-     * this method will add that "1" into your date regardless of the format.
-     *
-     * @param string $month
-     * @return string
-     */
-    public static function first_of_month_timestamp($month = '')
-    {
-        $month = (string) $month;
-        $year  = '';
-        // check if the incoming string has a year in it or not
-        if (preg_match('/\b\d{4}\b/', $month, $matches)) {
-            $year = $matches[0];
-            // ten remove that from the month string as well as any spaces
-            $month = trim(str_replace($year, '', $month));
-            // add a space before the year
-            $year = " {$year}";
-        }
-        // return timestamp for something like "February 1 2017"
-        return strtotime("{$month} 1{$year}");
-    }
-
-
-    /**
-     * This simply returns the timestamp for tomorrow (midnight next day) in this sites timezone.  So it may be midnight
-     * for this sites timezone, but the timestamp could be some other time GMT.
-     */
-    public static function tomorrow()
-    {
-        //The multiplication of -1 ensures that we switch positive offsets to negative and negative offsets to positive
-        //before adding to the timestamp.  Why? Because we want tomorrow to be for midnight the next day in THIS timezone
-        //not an offset from midnight in UTC.  So if we're starting with UTC 00:00:00, then we want to make sure the
-        //final timestamp is equivalent to midnight in this timezone as represented in GMT.
-        return strtotime('tomorrow') + (self::get_site_timezone_gmt_offset() * -1);
-    }
-
-
-    /**
-     * **
-     * Gives a nicely-formatted list of timezone strings.
-     * Copied from the core wp function by the same name so we could customize to remove UTC offsets.
-     *
-     * @since     4.9.40.rc.008
-     * @staticvar bool $mo_loaded
-     * @staticvar string $locale_loaded
-     * @param string $selected_zone Selected timezone.
-     * @param string $locale        Optional. Locale to load the timezones in. Default current site locale.
-     * @return string
-     */
-    public static function wp_timezone_choice($selected_zone, $locale = null)
-    {
-        static $mo_loaded = false, $locale_loaded = null;
-        $continents = array(
-            'Africa',
-            'America',
-            'Antarctica',
-            'Arctic',
-            'Asia',
-            'Atlantic',
-            'Australia',
-            'Europe',
-            'Indian',
-            'Pacific',
-        );
-        // Load translations for continents and cities.
-        if (! $mo_loaded || $locale !== $locale_loaded) {
-            $locale_loaded = $locale ? $locale : get_locale();
-            $mofile        = WP_LANG_DIR . '/continents-cities-' . $locale_loaded . '.mo';
-            unload_textdomain('continents-cities');
-            load_textdomain('continents-cities', $mofile);
-            $mo_loaded = true;
-        }
-        $zone_data = array();
-        foreach (timezone_identifiers_list() as $zone) {
-            $zone = explode('/', $zone);
-            if (! in_array($zone[0], $continents, true)) {
-                continue;
-            }
-            // This determines what gets set and translated - we don't translate Etc/* strings here, they are done later
-            $exists      = array(
-                0 => isset($zone[0]) && $zone[0],
-                1 => isset($zone[1]) && $zone[1],
-                2 => isset($zone[2]) && $zone[2],
-            );
-            $exists[3]   = $exists[0] && $zone[0] !== 'Etc';
-            $exists[4]   = $exists[1] && $exists[3];
-            $exists[5]   = $exists[2] && $exists[3];
-            $zone_data[] = array(
-                'continent'   => $exists[0] ? $zone[0] : '',
-                'city'        => $exists[1] ? $zone[1] : '',
-                'subcity'     => $exists[2] ? $zone[2] : '',
-                't_continent' => $exists[3]
-                    ? translate(str_replace('_', ' ', $zone[0]), 'continents-cities')
-                    : '',
-                't_city'      => $exists[4]
-                    ? translate(str_replace('_', ' ', $zone[1]), 'continents-cities')
-                    : '',
-                't_subcity'   => $exists[5]
-                    ? translate(str_replace('_', ' ', $zone[2]), 'continents-cities')
-                    : '',
-            );
-        }
-        usort($zone_data, '_wp_timezone_choice_usort_callback');
-        $structure = array();
-        if (empty($selected_zone)) {
-            $structure[] = '<option selected="selected" value="">' . __('Select a city') . '</option>';
-        }
-        foreach ($zone_data as $key => $zone) {
-            // Build value in an array to join later
-            $value = array($zone['continent']);
-            if (empty($zone['city'])) {
-                // It's at the continent level (generally won't happen)
-                $display = $zone['t_continent'];
-            } else {
-                // It's inside a continent group
-                // Continent optgroup
-                if (! isset($zone_data[ $key - 1 ]) || $zone_data[ $key - 1 ]['continent'] !== $zone['continent']) {
-                    $label       = $zone['t_continent'];
-                    $structure[] = '<optgroup label="' . esc_attr($label) . '">';
-                }
-                // Add the city to the value
-                $value[] = $zone['city'];
-                $display = $zone['t_city'];
-                if (! empty($zone['subcity'])) {
-                    // Add the subcity to the value
-                    $value[] = $zone['subcity'];
-                    $display .= ' - ' . $zone['t_subcity'];
-                }
-            }
-            // Build the value
-            $value       = implode('/', $value);
-            $selected    = $value === $selected_zone ? ' selected="selected"' : '';
-            $structure[] = '<option value="' . esc_attr($value) . '"' . $selected . '>'
-                           . esc_html($display)
-                           . '</option>';
-            // Close continent optgroup
-            if (! empty($zone['city'])
-                && (
-                    ! isset($zone_data[ $key + 1 ])
-                    || (isset($zone_data[ $key + 1 ]) && $zone_data[ $key + 1 ]['continent'] !== $zone['continent'])
-                )
-            ) {
-                $structure[] = '</optgroup>';
-            }
-        }
-        return implode("\n", $structure);
-    }
-
-
-    /**
-     * Shim for the WP function `get_user_locale` that was added in WordPress 4.7.0
-     *
-     * @param int|WP_User $user_id
-     * @return string
-     */
-    public static function get_user_locale($user_id = 0)
-    {
-        if (function_exists('get_user_locale')) {
-            return get_user_locale($user_id);
-        }
-        return get_locale();
-    }
+	endif;
+	}
+
+
+	/**
+	 * This method will take an incoming unix timestamp and add the offset to it for the given timezone_string.
+	 * If no unix timestamp is given then time() is used.  If no timezone is given then the set timezone string for
+	 * the site is used.
+	 * This is used typically when using a Unix timestamp any core WP functions that expect their specially
+	 * computed timestamp (i.e. date_i18n() )
+	 *
+	 * @param int    $unix_timestamp                  if 0, then time() will be used.
+	 * @param string $timezone_string                 timezone_string. If empty, then the current set timezone for the
+	 *                                                site will be used.
+	 * @return int $unix_timestamp with the offset applied for the given timezone.
+	 * @throws EE_Error
+	 */
+	public static function get_timestamp_with_offset($unix_timestamp = 0, $timezone_string = '')
+	{
+		$unix_timestamp  = $unix_timestamp === 0 ? time() : (int) $unix_timestamp;
+		$timezone_string = self::get_valid_timezone_string($timezone_string);
+		$TimeZone        = new DateTimeZone($timezone_string);
+		$DateTime        = new DateTime('@' . $unix_timestamp, $TimeZone);
+		$offset          = timezone_offset_get($TimeZone, $DateTime);
+		return (int) $DateTime->format('U') + (int) $offset;
+	}
+
+
+	/**
+	 *    _set_date_time_field
+	 *    modifies EE_Base_Class EE_Datetime_Field objects
+	 *
+	 * @param  EE_Base_Class $obj                 EE_Base_Class object
+	 * @param    DateTime    $DateTime            PHP DateTime object
+	 * @param  string        $datetime_field_name the datetime fieldname to be manipulated
+	 * @return EE_Base_Class
+	 * @throws EE_Error
+	 */
+	protected static function _set_date_time_field(EE_Base_Class $obj, DateTime $DateTime, $datetime_field_name)
+	{
+		// grab current datetime format
+		$current_format = $obj->get_format();
+		// set new full timestamp format
+		$obj->set_date_format(EE_Datetime_Field::mysql_date_format);
+		$obj->set_time_format(EE_Datetime_Field::mysql_time_format);
+		// set the new date value using a full timestamp format so that no data is lost
+		$obj->set($datetime_field_name, $DateTime->format(EE_Datetime_Field::mysql_timestamp_format));
+		// reset datetime formats
+		$obj->set_date_format($current_format[0]);
+		$obj->set_time_format($current_format[1]);
+		return $obj;
+	}
+
+
+	/**
+	 *    date_time_add
+	 *    helper for doing simple datetime calculations on a given datetime from EE_Base_Class
+	 *    and modifying it IN the EE_Base_Class so you don't have to do anything else.
+	 *
+	 * @param  EE_Base_Class $obj                 EE_Base_Class object
+	 * @param  string        $datetime_field_name name of the EE_Datetime_Filed datatype db column to be manipulated
+	 * @param  string        $period              what you are adding. The options are (years, months, days, hours,
+	 *                                            minutes, seconds) defaults to years
+	 * @param  integer       $value               what you want to increment the time by
+	 * @return EE_Base_Class return the EE_Base_Class object so right away you can do something with it
+	 *                                            (chaining)
+	 * @throws EE_Error
+	 * @throws Exception
+	 */
+	public static function date_time_add(EE_Base_Class $obj, $datetime_field_name, $period = 'years', $value = 1)
+	{
+		//get the raw UTC date.
+		$DateTime = $obj->get_DateTime_object($datetime_field_name);
+		$DateTime = EEH_DTT_Helper::calc_date($DateTime, $period, $value);
+		return EEH_DTT_Helper::_set_date_time_field($obj, $DateTime, $datetime_field_name);
+	}
+
+
+	/**
+	 *    date_time_subtract
+	 *    same as date_time_add except subtracting value instead of adding.
+	 *
+	 * @param EE_Base_Class $obj
+	 * @param  string       $datetime_field_name name of the EE_Datetime_Filed datatype db column to be manipulated
+	 * @param string        $period
+	 * @param int           $value
+	 * @return EE_Base_Class
+	 * @throws EE_Error
+	 * @throws Exception
+	 */
+	public static function date_time_subtract(EE_Base_Class $obj, $datetime_field_name, $period = 'years', $value = 1)
+	{
+		//get the raw UTC date
+		$DateTime = $obj->get_DateTime_object($datetime_field_name);
+		$DateTime = EEH_DTT_Helper::calc_date($DateTime, $period, $value, '-');
+		return EEH_DTT_Helper::_set_date_time_field($obj, $DateTime, $datetime_field_name);
+	}
+
+
+	/**
+	 * Simply takes an incoming DateTime object and does calculations on it based on the incoming parameters
+	 *
+	 * @param  DateTime   $DateTime DateTime object
+	 * @param  string     $period   a value to indicate what interval is being used in the calculation. The options are
+	 *                              'years', 'months', 'days', 'hours', 'minutes', 'seconds'. Defaults to years.
+	 * @param  int|string $value    What you want to increment the date by
+	 * @param  string     $operand  What operand you wish to use for the calculation
+	 * @return DateTime return whatever type came in.
+	 * @throws Exception
+	 * @throws EE_Error
+	 */
+	protected static function _modify_datetime_object(DateTime $DateTime, $period = 'years', $value = 1, $operand = '+')
+	{
+		if (! $DateTime instanceof DateTime) {
+			throw new EE_Error(
+				sprintf(
+					esc_html__('Expected a PHP DateTime object, but instead received %1$s', 'event_espresso'),
+					print_r($DateTime, true)
+				)
+			);
+		}
+		switch ($period) {
+			case 'years' :
+				$value = 'P' . $value . 'Y';
+				break;
+			case 'months' :
+				$value = 'P' . $value . 'M';
+				break;
+			case 'weeks' :
+				$value = 'P' . $value . 'W';
+				break;
+			case 'days' :
+				$value = 'P' . $value . 'D';
+				break;
+			case 'hours' :
+				$value = 'PT' . $value . 'H';
+				break;
+			case 'minutes' :
+				$value = 'PT' . $value . 'M';
+				break;
+			case 'seconds' :
+				$value = 'PT' . $value . 'S';
+				break;
+		}
+		switch ($operand) {
+			case '+':
+				$DateTime->add(new DateInterval($value));
+				break;
+			case '-':
+				$DateTime->sub(new DateInterval($value));
+				break;
+		}
+		return $DateTime;
+	}
+
+
+	/**
+	 * Simply takes an incoming Unix timestamp and does calculations on it based on the incoming parameters
+	 *
+	 * @param  int     $timestamp Unix timestamp
+	 * @param  string  $period    a value to indicate what interval is being used in the calculation. The options are
+	 *                            'years', 'months', 'days', 'hours', 'minutes', 'seconds'. Defaults to years.
+	 * @param  integer $value     What you want to increment the date by
+	 * @param  string  $operand   What operand you wish to use for the calculation
+	 * @return int
+	 * @throws EE_Error
+	 */
+	protected static function _modify_timestamp($timestamp, $period = 'years', $value = 1, $operand = '+')
+	{
+		if (! preg_match(EE_Datetime_Field::unix_timestamp_regex, $timestamp)) {
+			throw new EE_Error(
+				sprintf(
+					esc_html__('Expected a Unix timestamp, but instead received %1$s', 'event_espresso'),
+					print_r($timestamp, true)
+				)
+			);
+		}
+		switch ($period) {
+			case 'years' :
+				$value = YEAR_IN_SECONDS * $value;
+				break;
+			case 'months' :
+				$value = YEAR_IN_SECONDS / 12 * $value;
+				break;
+			case 'weeks' :
+				$value = WEEK_IN_SECONDS * $value;
+				break;
+			case 'days' :
+				$value = DAY_IN_SECONDS * $value;
+				break;
+			case 'hours' :
+				$value = HOUR_IN_SECONDS * $value;
+				break;
+			case 'minutes' :
+				$value = MINUTE_IN_SECONDS * $value;
+				break;
+		}
+		switch ($operand) {
+			case '+':
+				$timestamp += $value;
+				break;
+			case '-':
+				$timestamp -= $value;
+				break;
+		}
+		return $timestamp;
+	}
+
+
+	/**
+	 * Simply takes an incoming UTC timestamp or DateTime object and does calculations on it based on the incoming
+	 * parameters and returns the new timestamp or DateTime.
+	 *
+	 * @param  int | DateTime $DateTime_or_timestamp DateTime object or Unix timestamp
+	 * @param  string         $period                a value to indicate what interval is being used in the
+	 *                                               calculation. The options are 'years', 'months', 'days', 'hours',
+	 *                                               'minutes', 'seconds'. Defaults to years.
+	 * @param  integer        $value                 What you want to increment the date by
+	 * @param  string         $operand               What operand you wish to use for the calculation
+	 * @return mixed string|DateTime          return whatever type came in.
+	 * @throws Exception
+	 * @throws EE_Error
+	 */
+	public static function calc_date($DateTime_or_timestamp, $period = 'years', $value = 1, $operand = '+')
+	{
+		if ($DateTime_or_timestamp instanceof DateTime) {
+			return EEH_DTT_Helper::_modify_datetime_object(
+				$DateTime_or_timestamp,
+				$period,
+				$value,
+				$operand
+			);
+		}
+		if (preg_match(EE_Datetime_Field::unix_timestamp_regex, $DateTime_or_timestamp)) {
+			return EEH_DTT_Helper::_modify_timestamp(
+				$DateTime_or_timestamp,
+				$period,
+				$value,
+				$operand
+			);
+		}
+		//error
+		return $DateTime_or_timestamp;
+	}
+
+
+	/**
+	 * The purpose of this helper method is to receive an incoming format string in php date/time format
+	 * and spit out the js and moment.js equivalent formats.
+	 * Note, if no format string is given, then it is assumed the user wants what is set for WP.
+	 * Note, js date and time formats are those used by the jquery-ui datepicker and the jquery-ui date-
+	 * time picker.
+	 *
+	 * @see http://stackoverflow.com/posts/16725290/ for the code inspiration.
+	 * @param string $date_format_string
+	 * @param string $time_format_string
+	 * @return array
+	 *              array(
+	 *              'js' => array (
+	 *              'date' => //date format
+	 *              'time' => //time format
+	 *              ),
+	 *              'moment' => //date and time format.
+	 *              )
+	 */
+	public static function convert_php_to_js_and_moment_date_formats(
+		$date_format_string = null,
+		$time_format_string = null
+	) {
+		if ($date_format_string === null) {
+			$date_format_string = (string) get_option('date_format');
+		}
+		if ($time_format_string === null) {
+			$time_format_string = (string) get_option('time_format');
+		}
+		$date_format = self::_php_to_js_moment_converter($date_format_string);
+		$time_format = self::_php_to_js_moment_converter($time_format_string);
+		return array(
+			'js'     => array(
+				'date' => $date_format['js'],
+				'time' => $time_format['js'],
+			),
+			'moment' => $date_format['moment'] . ' ' . $time_format['moment'],
+		);
+	}
+
+
+	/**
+	 * This converts incoming format string into js and moment variations.
+	 *
+	 * @param string $format_string incoming php format string
+	 * @return array js and moment formats.
+	 */
+	protected static function _php_to_js_moment_converter($format_string)
+	{
+		/**
+		 * This is a map of symbols for formats.
+		 * The index is the php symbol, the equivalent values are in the array.
+		 *
+		 * @var array
+		 */
+		$symbols_map          = array(
+			// Day
+			//01
+			'd' => array(
+				'js'     => 'dd',
+				'moment' => 'DD',
+			),
+			//Mon
+			'D' => array(
+				'js'     => 'D',
+				'moment' => 'ddd',
+			),
+			//1,2,...31
+			'j' => array(
+				'js'     => 'd',
+				'moment' => 'D',
+			),
+			//Monday
+			'l' => array(
+				'js'     => 'DD',
+				'moment' => 'dddd',
+			),
+			//ISO numeric representation of the day of the week (1-6)
+			'N' => array(
+				'js'     => '',
+				'moment' => 'E',
+			),
+			//st,nd.rd
+			'S' => array(
+				'js'     => '',
+				'moment' => 'o',
+			),
+			//numeric representation of day of week (0-6)
+			'w' => array(
+				'js'     => '',
+				'moment' => 'd',
+			),
+			//day of year starting from 0 (0-365)
+			'z' => array(
+				'js'     => 'o',
+				'moment' => 'DDD' //note moment does not start with 0 so will need to modify by subtracting 1
+			),
+			// Week
+			//ISO-8601 week number of year (weeks starting on monday)
+			'W' => array(
+				'js'     => '',
+				'moment' => 'w',
+			),
+			// Month
+			// January...December
+			'F' => array(
+				'js'     => 'MM',
+				'moment' => 'MMMM',
+			),
+			//01...12
+			'm' => array(
+				'js'     => 'mm',
+				'moment' => 'MM',
+			),
+			//Jan...Dec
+			'M' => array(
+				'js'     => 'M',
+				'moment' => 'MMM',
+			),
+			//1-12
+			'n' => array(
+				'js'     => 'm',
+				'moment' => 'M',
+			),
+			//number of days in given month
+			't' => array(
+				'js'     => '',
+				'moment' => '',
+			),
+			// Year
+			//whether leap year or not 1/0
+			'L' => array(
+				'js'     => '',
+				'moment' => '',
+			),
+			//ISO-8601 year number
+			'o' => array(
+				'js'     => '',
+				'moment' => 'GGGG',
+			),
+			//1999...2003
+			'Y' => array(
+				'js'     => 'yy',
+				'moment' => 'YYYY',
+			),
+			//99...03
+			'y' => array(
+				'js'     => 'y',
+				'moment' => 'YY',
+			),
+			// Time
+			// am/pm
+			'a' => array(
+				'js'     => 'tt',
+				'moment' => 'a',
+			),
+			// AM/PM
+			'A' => array(
+				'js'     => 'TT',
+				'moment' => 'A',
+			),
+			// Swatch Internet Time?!?
+			'B' => array(
+				'js'     => '',
+				'moment' => '',
+			),
+			//1...12
+			'g' => array(
+				'js'     => 'h',
+				'moment' => 'h',
+			),
+			//0...23
+			'G' => array(
+				'js'     => 'H',
+				'moment' => 'H',
+			),
+			//01...12
+			'h' => array(
+				'js'     => 'hh',
+				'moment' => 'hh',
+			),
+			//00...23
+			'H' => array(
+				'js'     => 'HH',
+				'moment' => 'HH',
+			),
+			//00..59
+			'i' => array(
+				'js'     => 'mm',
+				'moment' => 'mm',
+			),
+			//seconds... 00...59
+			's' => array(
+				'js'     => 'ss',
+				'moment' => 'ss',
+			),
+			//microseconds
+			'u' => array(
+				'js'     => '',
+				'moment' => '',
+			),
+		);
+		$jquery_ui_format     = '';
+		$moment_format        = '';
+		$escaping             = false;
+		$format_string_length = strlen($format_string);
+		for ($i = 0; $i < $format_string_length; $i++) {
+			$char = $format_string[ $i ];
+			if ($char === '\\') { // PHP date format escaping character
+				$i++;
+				if ($escaping) {
+					$jquery_ui_format .= $format_string[ $i ];
+					$moment_format    .= $format_string[ $i ];
+				} else {
+					$jquery_ui_format .= '\'' . $format_string[ $i ];
+					$moment_format    .= $format_string[ $i ];
+				}
+				$escaping = true;
+			} else {
+				if ($escaping) {
+					$jquery_ui_format .= "'";
+					$moment_format    .= "'";
+					$escaping         = false;
+				}
+				if (isset($symbols_map[ $char ])) {
+					$jquery_ui_format .= $symbols_map[ $char ]['js'];
+					$moment_format    .= $symbols_map[ $char ]['moment'];
+				} else {
+					$jquery_ui_format .= $char;
+					$moment_format    .= $char;
+				}
+			}
+		}
+		return array('js' => $jquery_ui_format, 'moment' => $moment_format);
+	}
+
+
+	/**
+	 * This takes an incoming format string and validates it to ensure it will work fine with PHP.
+	 *
+	 * @param string $format_string   Incoming format string for php date().
+	 * @return mixed bool|array  If all is okay then TRUE is returned.  Otherwise an array of validation
+	 *                                errors is returned.  So for client code calling, check for is_array() to
+	 *                                indicate failed validations.
+	 */
+	public static function validate_format_string($format_string)
+	{
+		$error_msg = array();
+		//time format checks
+		switch (true) {
+			case   strpos($format_string, 'h') !== false  :
+			case   strpos($format_string, 'g') !== false :
+				/**
+				 * if the time string has a lowercase 'h' which == 12 hour time format and there
+				 * is not any ante meridiem format ('a' or 'A').  Then throw an error because its
+				 * too ambiguous and PHP won't be able to figure out whether 1 = 1pm or 1am.
+				 */
+				if (stripos($format_string, 'A') === false) {
+					$error_msg[] = esc_html__(
+						'There is a  time format for 12 hour time but no  "a" or "A" to indicate am/pm.  Without this distinction, PHP is unable to determine if a "1" for the hour value equals "1pm" or "1am".',
+						'event_espresso'
+					);
+				}
+				break;
+		}
+		return empty($error_msg) ? true : $error_msg;
+	}
+
+
+	/**
+	 *     If the the first date starts at midnight on one day, and the next date ends at midnight on the
+	 *     very next day then this method will return true.
+	 *    If $date_1 = 2015-12-15 00:00:00 and $date_2 = 2015-12-16 00:00:00 then this function will return true.
+	 *    If $date_1 = 2015-12-15 03:00:00 and $date_2 = 2015-12_16 03:00:00 then this function will return false.
+	 *    If $date_1 = 2015-12-15 00:00:00 and $date_2 = 2015-12-15 00:00:00 then this function will return true.
+	 *
+	 * @param mixed $date_1
+	 * @param mixed $date_2
+	 * @return bool
+	 */
+	public static function dates_represent_one_24_hour_date($date_1, $date_2)
+	{
+
+		if (
+			(! $date_1 instanceof DateTime || ! $date_2 instanceof DateTime)
+			|| ($date_1->format(EE_Datetime_Field::mysql_time_format) !== '00:00:00'
+				|| $date_2->format(
+					EE_Datetime_Field::mysql_time_format
+				) !== '00:00:00')
+		) {
+			return false;
+		}
+		return $date_2->format('U') - $date_1->format('U') === 86400;
+	}
+
+
+	/**
+	 * This returns the appropriate query interval string that can be used in sql queries involving mysql Date
+	 * Functions.
+	 *
+	 * @param string $timezone_string    A timezone string in a valid format to instantiate a DateTimeZone object.
+	 * @param string $field_for_interval The Database field that is the interval is applied to in the query.
+	 * @return string
+	 */
+	public static function get_sql_query_interval_for_offset($timezone_string, $field_for_interval)
+	{
+		try {
+			/** need to account for timezone offset on the selects */
+			$DateTimeZone = new DateTimeZone($timezone_string);
+		} catch (Exception $e) {
+			$DateTimeZone = null;
+		}
+		/**
+		 * Note get_option( 'gmt_offset') returns a value in hours, whereas DateTimeZone::getOffset returns values in seconds.
+		 * Hence we do the calc for DateTimeZone::getOffset.
+		 */
+		$offset         = $DateTimeZone instanceof DateTimeZone
+			? $DateTimeZone->getOffset(new DateTime('now')) / HOUR_IN_SECONDS
+			: (float) get_option('gmt_offset');
+		$query_interval = $offset < 0
+			? 'DATE_SUB(' . $field_for_interval . ', INTERVAL ' . $offset * -1 . ' HOUR)'
+			: 'DATE_ADD(' . $field_for_interval . ', INTERVAL ' . $offset . ' HOUR)';
+		return $query_interval;
+	}
+
+
+	/**
+	 * Retrieves the site's default timezone and returns it formatted so it's ready for display
+	 * to users. If you want to customize how its displayed feel free to fetch the 'timezone_string'
+	 * and 'gmt_offset' WordPress options directly; or use the filter
+	 * FHEE__EEH_DTT_Helper__get_timezone_string_for_display
+	 * (although note that we remove any HTML that may be added)
+	 *
+	 * @return string
+	 */
+	public static function get_timezone_string_for_display()
+	{
+		$pretty_timezone = apply_filters('FHEE__EEH_DTT_Helper__get_timezone_string_for_display', '');
+		if (! empty($pretty_timezone)) {
+			return esc_html($pretty_timezone);
+		}
+		$timezone_string = get_option('timezone_string');
+		if ($timezone_string) {
+			static $mo_loaded = false;
+			// Load translations for continents and cities just like wp_timezone_choice does
+			if (! $mo_loaded) {
+				$locale = get_locale();
+				$mofile = WP_LANG_DIR . '/continents-cities-' . $locale . '.mo';
+				load_textdomain('continents-cities', $mofile);
+				$mo_loaded = true;
+			}
+			//well that was easy.
+			$parts = explode('/', $timezone_string);
+			//remove the continent
+			unset($parts[0]);
+			$t_parts = array();
+			foreach ($parts as $part) {
+				$t_parts[] = translate(str_replace('_', ' ', $part), 'continents-cities');
+			}
+			return implode(' - ', $t_parts);
+		}
+		//they haven't set the timezone string, so let's return a string like "UTC+1"
+		$gmt_offset = get_option('gmt_offset');
+		$prefix     = (int) $gmt_offset >= 0 ? '+' : '';
+		$parts      = explode('.', (string) $gmt_offset);
+		if (count($parts) === 1) {
+			$parts[1] = '00';
+		} else {
+			//convert the part after the decimal, eg "5" (from x.5) or "25" (from x.25)
+			//to minutes, eg 30 or 15, respectively
+			$hour_fraction = (float) ('0.' . $parts[1]);
+			$parts[1]      = (string) $hour_fraction * 60;
+		}
+		return sprintf(__('UTC%1$s', 'event_espresso'), $prefix . implode(':', $parts));
+	}
+
+
+
+	/**
+	 * So PHP does this awesome thing where if you are trying to get a timestamp
+	 * for a month using a string like "February" or "February 2017",
+	 * and you don't specify a day as part of your string,
+	 * then PHP will use whatever the current day of the month is.
+	 * IF the current day of the month happens to be the 30th or 31st,
+	 * then PHP gets really confused by a date like February 30,
+	 * so instead of saying
+	 *      "Hey February only has 28 days (this year)...
+	 *      ...you must have meant the last day of the month!"
+	 * PHP does the next most logical thing, and bumps the date up to March 2nd,
+	 * because someone requesting February 30th obviously meant March 1st!
+	 * The way around this is to always set the day to the first,
+	 * so that the month will stay on the month you wanted.
+	 * this method will add that "1" into your date regardless of the format.
+	 *
+	 * @param string $month
+	 * @return string
+	 */
+	public static function first_of_month_timestamp($month = '')
+	{
+		$month = (string) $month;
+		$year  = '';
+		// check if the incoming string has a year in it or not
+		if (preg_match('/\b\d{4}\b/', $month, $matches)) {
+			$year = $matches[0];
+			// ten remove that from the month string as well as any spaces
+			$month = trim(str_replace($year, '', $month));
+			// add a space before the year
+			$year = " {$year}";
+		}
+		// return timestamp for something like "February 1 2017"
+		return strtotime("{$month} 1{$year}");
+	}
+
+
+	/**
+	 * This simply returns the timestamp for tomorrow (midnight next day) in this sites timezone.  So it may be midnight
+	 * for this sites timezone, but the timestamp could be some other time GMT.
+	 */
+	public static function tomorrow()
+	{
+		//The multiplication of -1 ensures that we switch positive offsets to negative and negative offsets to positive
+		//before adding to the timestamp.  Why? Because we want tomorrow to be for midnight the next day in THIS timezone
+		//not an offset from midnight in UTC.  So if we're starting with UTC 00:00:00, then we want to make sure the
+		//final timestamp is equivalent to midnight in this timezone as represented in GMT.
+		return strtotime('tomorrow') + (self::get_site_timezone_gmt_offset() * -1);
+	}
+
+
+	/**
+	 * **
+	 * Gives a nicely-formatted list of timezone strings.
+	 * Copied from the core wp function by the same name so we could customize to remove UTC offsets.
+	 *
+	 * @since     4.9.40.rc.008
+	 * @staticvar bool $mo_loaded
+	 * @staticvar string $locale_loaded
+	 * @param string $selected_zone Selected timezone.
+	 * @param string $locale        Optional. Locale to load the timezones in. Default current site locale.
+	 * @return string
+	 */
+	public static function wp_timezone_choice($selected_zone, $locale = null)
+	{
+		static $mo_loaded = false, $locale_loaded = null;
+		$continents = array(
+			'Africa',
+			'America',
+			'Antarctica',
+			'Arctic',
+			'Asia',
+			'Atlantic',
+			'Australia',
+			'Europe',
+			'Indian',
+			'Pacific',
+		);
+		// Load translations for continents and cities.
+		if (! $mo_loaded || $locale !== $locale_loaded) {
+			$locale_loaded = $locale ? $locale : get_locale();
+			$mofile        = WP_LANG_DIR . '/continents-cities-' . $locale_loaded . '.mo';
+			unload_textdomain('continents-cities');
+			load_textdomain('continents-cities', $mofile);
+			$mo_loaded = true;
+		}
+		$zone_data = array();
+		foreach (timezone_identifiers_list() as $zone) {
+			$zone = explode('/', $zone);
+			if (! in_array($zone[0], $continents, true)) {
+				continue;
+			}
+			// This determines what gets set and translated - we don't translate Etc/* strings here, they are done later
+			$exists      = array(
+				0 => isset($zone[0]) && $zone[0],
+				1 => isset($zone[1]) && $zone[1],
+				2 => isset($zone[2]) && $zone[2],
+			);
+			$exists[3]   = $exists[0] && $zone[0] !== 'Etc';
+			$exists[4]   = $exists[1] && $exists[3];
+			$exists[5]   = $exists[2] && $exists[3];
+			$zone_data[] = array(
+				'continent'   => $exists[0] ? $zone[0] : '',
+				'city'        => $exists[1] ? $zone[1] : '',
+				'subcity'     => $exists[2] ? $zone[2] : '',
+				't_continent' => $exists[3]
+					? translate(str_replace('_', ' ', $zone[0]), 'continents-cities')
+					: '',
+				't_city'      => $exists[4]
+					? translate(str_replace('_', ' ', $zone[1]), 'continents-cities')
+					: '',
+				't_subcity'   => $exists[5]
+					? translate(str_replace('_', ' ', $zone[2]), 'continents-cities')
+					: '',
+			);
+		}
+		usort($zone_data, '_wp_timezone_choice_usort_callback');
+		$structure = array();
+		if (empty($selected_zone)) {
+			$structure[] = '<option selected="selected" value="">' . __('Select a city') . '</option>';
+		}
+		foreach ($zone_data as $key => $zone) {
+			// Build value in an array to join later
+			$value = array($zone['continent']);
+			if (empty($zone['city'])) {
+				// It's at the continent level (generally won't happen)
+				$display = $zone['t_continent'];
+			} else {
+				// It's inside a continent group
+				// Continent optgroup
+				if (! isset($zone_data[ $key - 1 ]) || $zone_data[ $key - 1 ]['continent'] !== $zone['continent']) {
+					$label       = $zone['t_continent'];
+					$structure[] = '<optgroup label="' . esc_attr($label) . '">';
+				}
+				// Add the city to the value
+				$value[] = $zone['city'];
+				$display = $zone['t_city'];
+				if (! empty($zone['subcity'])) {
+					// Add the subcity to the value
+					$value[] = $zone['subcity'];
+					$display .= ' - ' . $zone['t_subcity'];
+				}
+			}
+			// Build the value
+			$value       = implode('/', $value);
+			$selected    = $value === $selected_zone ? ' selected="selected"' : '';
+			$structure[] = '<option value="' . esc_attr($value) . '"' . $selected . '>'
+						   . esc_html($display)
+						   . '</option>';
+			// Close continent optgroup
+			if (! empty($zone['city'])
+				&& (
+					! isset($zone_data[ $key + 1 ])
+					|| (isset($zone_data[ $key + 1 ]) && $zone_data[ $key + 1 ]['continent'] !== $zone['continent'])
+				)
+			) {
+				$structure[] = '</optgroup>';
+			}
+		}
+		return implode("\n", $structure);
+	}
+
+
+	/**
+	 * Shim for the WP function `get_user_locale` that was added in WordPress 4.7.0
+	 *
+	 * @param int|WP_User $user_id
+	 * @return string
+	 */
+	public static function get_user_locale($user_id = 0)
+	{
+		if (function_exists('get_user_locale')) {
+			return get_user_locale($user_id);
+		}
+		return get_locale();
+	}
 
 }