<?php
/**
 * System Status Page
 *
 * @package SimpleCalendar/Admin
 */
namespace SimpleCalendar\Admin\Pages;

use SimpleCalendar\Abstracts\Admin_Page;

if (!defined('ABSPATH')) {
	exit();
}

/**
 * System status.
 *
 * Generates reports on current installation, with information for debugging or support purposes.
 *
 * @since 3.0.0
 */
class System_Status extends Admin_Page
{
	/**
	 * Constructor.
	 *
	 * @since 3.0.0
	 */
	public function __construct()
	{
		$this->id = $tab = 'system-status';
		$this->option_group = $page = 'tools';
		$this->label = __('System Report', 'google-calendar-events');
		$this->description = '';
		$this->sections = $this->add_sections();
		$this->fields = $this->add_fields();

		// Disable the submit button for this page.
		add_filter('simcal_admin_page_' . $page . '_' . $tab . '_submit', function () {
			return false;
		});

		// Add html.
		add_action('simcal_admin_page_' . $page . '_' . $tab . '_end', [$this, 'html']);
	}

	/**
	 * Output page markup.
	 *
	 * @since 3.0.0
	 */
	public function html()
	{
		?>
		<div id="simcal-system-status-report">
			<p><?php _e('Please copy and paste this information when contacting support:', 'google-calendar-events'); ?> </p>
			<textarea readonly="readonly" onclick="this.select();"></textarea>
			<p><?php _e(
   	'You can also download your information as a text file to attach, or simply view it below.',
   	'google-calendar-events',
   ); ?></p>
			<p><a href="#" id="simcal-system-status-report-download" class="button button-primary"><?php _e(
   	'Download System Report',
   	'google-calendar-events',
   ); ?></a></p>
		</div>
		<hr>
		<?php
  global $wpdb;
  $wp_version = get_bloginfo('version');

  $sections = [];
  $panels = [
  	'wordpress' => [
  		'label' => __('WordPress Installation', 'google-calendar-events'),
  		'export' => 'WordPress Installation',
  	],
  	'theme' => [
  		'label' => __('Active Theme', 'google-calendar-events'),
  		'export' => 'Active Theme',
  	],
  	'plugins' => [
  		'label' => __('Active Plugins', 'google-calendar-events'),
  		'export' => 'Active Plugins',
  	],
  	'server' => [
  		'label' => __('Server Environment', 'google-calendar-events'),
  		'export' => 'Server Environment',
  	],
  	'client' => [
  		'label' => __('Client Information', 'google-calendar-events'),
  		'export' => 'Client Information',
  	],
  ];

  /**
   * Plugin Information
   * ==================
   */

  // @todo add report information section for current plugin

  /**
   * WordPress Installation
   * ======================
   */

  $debug_mode = $script_debug = __('No', 'google-calendar-events');
  if (defined('WP_DEBUG')) {
  	$debug_mode = true === WP_DEBUG ? __('Yes', 'google-calendar-events') : $debug_mode;
  }
  if (defined('SCRIPT_DEBUG')) {
  	$script_debug = true === SCRIPT_DEBUG ? __('Yes', 'google-calendar-events') : $script_debug;
  }

  $memory = $this->let_to_num(WP_MEMORY_LIMIT);
  $memory_export = size_format($memory);
  if ($memory < 67108864) {
  	$memory =
  		'<mark class="error">' .
  		sprintf(
  			__(
  				'%1$s - It is recomendend to set memory to at least 64MB. See: <a href="%2$s" target="_blank">Increasing memory allocated to PHP</a>',
  				'google-calendar-events',
  			),
  			$memory_export,
  			'http://codex.wordpress.org/Editing_wp-config.php#Increasing_memory_allocated_to_PHP',
  		) .
  		'</mark>';
  } else {
  	$memory = '<mark class="ok">' . $memory_export . '</mark>';
  }

  $permalinks = get_option('permalink_structure');
  $permalinks = empty($permalinks) ? '/?' : $permalinks;

  $is_multisite = is_multisite();

  $sections['wordpress'] = [
  	'name' => [
  		'label' => __('Site Name', 'google-calendar-events'),
  		'label_export' => 'Site Name',
  		'result' => get_bloginfo('name'),
  	],
  	'home_url' => [
  		'label' => __('Home URL', 'google-calendar-events'),
  		'label_export' => 'Home URL',
  		'result' => home_url(),
  	],
  	'site_url' => [
  		'label' => __('Site URL', 'google-calendar-events'),
  		'label_export' => 'Site URL',
  		'result' => site_url(),
  	],
  	'version' => [
  		'label' => __('Version', 'google-calendar-events'),
  		'label_export' => 'Version',
  		'result' => $wp_version,
  	],
  	'locale' => [
  		'label' => __('Locale', 'google-calendar-events'),
  		'label_export' => 'Locale',
  		'result' => get_locale(),
  	],
  	'wp_timezone' => [
  		'label' => __('Timezone', 'google-calendar-events'),
  		'label_export' => 'Timezone',
  		'result' => simcal_get_wp_timezone(),
  	],
  	'multisite' => [
  		'label' => __('Multisite', 'google-calendar-events'),
  		'label_export' => 'Multisite',
  		'result' => $is_multisite ? __('Yes', 'google-calendar-events') : __('No', 'google-calendar-events'),
  		'result_export' => $is_multisite ? 'Yes' : 'No',
  	],
  	'permalink' => [
  		'label' => __('Permalinks', 'google-calendar-events'),
  		'label_export' => 'Permalinks',
  		'result' => '<code>' . $permalinks . '</code>',
  		'result_export' => $permalinks,
  	],
  	'memory_limit' => [
  		'label' => 'WP Memory Limit',
  		'result' => $memory,
  		'result_export' => $memory_export,
  	],
  	'debug_mode' => [
  		'label' => 'WP Debug Mode',
  		'result' => $debug_mode,
  	],
  	'script_debug' => [
  		'label' => 'Script Debug',
  		'result' => $script_debug,
  	],
  ];

  /**
   * Active Theme
   * ============
   */

  include_once ABSPATH . 'wp-admin/includes/theme-install.php';

  if (version_compare($wp_version, '3.4', '<')) {
  	$active_theme = get_theme_data(get_stylesheet_directory() . '/style.css');
  	$theme_name = '<a href="' . $active_theme['URI'] . '" target="_blank">' . $active_theme['Name'] . '</a>';
  	$theme_version = $active_theme['Version'];
  	$theme_author = '<a href="' . $active_theme['AuthorURI'] . '" target="_blank">' . $active_theme['Author'] . '</a>';
  	$theme_export = $active_theme['Name'] . ' - ' . $theme_version;
  } else {
  	$active_theme = wp_get_theme();
  	$theme_name = '<a href="' . $active_theme->ThemeURI . '" target="_blank">' . $active_theme->Name . '</a>';
  	$theme_version = $active_theme->Version;
  	$theme_author = $active_theme->Author;
  	$theme_export = $active_theme->Name . ' - ' . $theme_version;
  }

  $theme_update_version = $theme_version;

  $api = themes_api('theme_information', [
  	'slug' => get_template(),
  	'fields' => ['sections' => false, 'tags' => false],
  ]);
  if ($api && !is_wp_error($api)) {
  	$theme_update_version = $api->version;
  }

  if (version_compare($theme_version, $theme_update_version, '<')) {
  	$theme_version =
  		'<mark class="error">' .
  		$theme_version .
  		' (' .
  		sprintf(__('%s is available', 'google-calendar-events'), esc_html($theme_update_version)) .
  		')</mark>';
  } else {
  	$theme_version = '<mark class="ok">' . $theme_version . '</mark>';
  }

  $theme = '<dl>';
  $theme .= '<dt>' . __('Name', 'google-calendar-events') . '</dt>';
  $theme .= '<dd>' . $theme_name . '</dd>';
  $theme .= '<dt>' . __('Author', 'google-calendar-events') . '</dt>';
  $theme .= '<dd>' . $theme_author . '</dd>';
  $theme .= '<dt>' . __('Version', 'google-calendar-events') . '</dt>';
  $theme .= '<dd>' . $theme_version . '</dd>';
  $theme .= '</dl>';

  $is_child_theme = is_child_theme();
  $parent_theme = $parent_theme_export = '-';

  if ($is_child_theme) {
  	if (version_compare($wp_version, '3.4', '<')) {
  		$parent_theme = $parent_theme_export = $active_theme['Template'];
  	} else {
  		$parent = wp_get_theme($active_theme->Template);
  		$parent_theme = '<dl>';
  		$parent_theme .= '<dt>' . __('Name', 'google-calendar-events') . '</dt>';
  		$parent_theme .= '<dd>' . $parent->Name . '</dd>';
  		$parent_theme .= '<dt>' . __('Author', 'google-calendar-events') . '</dt>';
  		$parent_theme .= '<dd>' . $parent->Author . '</dd>';
  		$parent_theme .= '<dt>' . __('Version', 'google-calendar-events') . '</dt>';
  		$parent_theme .= '<dd>' . $parent->Version . '</dd>';
  		$parent_theme .= '</dl>';

  		$parent_theme_export = strip_tags($parent->Name) . ' - ' . $parent->Version;
  	}
  }

  $sections['theme'] = [
  	'theme' => [
  		'label' => __('Theme Information', 'google-calendar-events'),
  		'label_export' => 'Theme',
  		'result' => $theme,
  		'result_export' => $theme_export,
  	],
  	'theme_child' => [
  		'label' => __('Child Theme', 'google-calendar-events'),
  		'label_export' => 'Child Theme',
  		'result' => $is_child_theme ? __('Yes', 'google-calendar-events') : __('No', 'google-calendar-events'),
  		'result_export' => $is_child_theme ? 'Yes' : 'No',
  	],
  	'theme_parent' => [
  		'label' => __('Parent Theme', 'google-calendar-events'),
  		'label_export' => 'Parent Theme',
  		'result' => $parent_theme,
  		'result_export' => $parent_theme_export,
  	],
  ];

  /**
   * Active Plugins
   * ==============
   */

  include_once ABSPATH . 'wp-admin/includes/plugin-install.php';

  $active_plugins = (array) get_option('active_plugins', []);
  if (is_multisite()) {
  	$active_plugins = array_merge($active_plugins, get_site_option('active_sitewide_plugins', []));
  }

  foreach ($active_plugins as $plugin) {
  	$plugin_data = @get_plugin_data(WP_PLUGIN_DIR . '/' . $plugin);

  	if (!empty($plugin_data['Name'])) {
  		$plugin_name = $plugin_data['Title'];
  		$plugin_author = $plugin_data['Author'];
  		$plugin_version = $plugin_update_version = $plugin_data['Version'];

  		// Afraid that querying many plugins may risk a timeout.
  		if (count($active_plugins) <= 10) {
  			$api = plugins_api('plugin_information', [
  				'slug' => $plugin_data['Name'],
  				'fields' => [
  					'version' => true,
  				],
  			]);
  			if ($api && !is_wp_error($api)) {
  				if (!empty($api->version)) {
  					$plugin_update_version = $api->version;
  					if (version_compare($plugin_version, $plugin_update_version, '<')) {
  						$plugin_version =
  							'<mark class="error">' .
  							$plugin_version .
  							' (' .
  							sprintf(__('%s is available', 'google-calendar-events'), esc_html($plugin_update_version)) .
  							')</mark>';
  					} else {
  						$plugin_version = '<mark class="ok">' . $plugin_version . '</mark>';
  					}
  				}
  			}
  		}

  		$plugin = '<dl>';
  		$plugin .= '<dt>' . __('Author', 'google-calendar-events') . '</dt>';
  		$plugin .= '<dd>' . $plugin_author . '</dd>';
  		$plugin .= '<dt>' . __('Version', 'google-calendar-events') . '</dt>';
  		$plugin .= '<dd>' . $plugin_version . '</dd>';
  		$plugin .= '</dl>';

  		$sections['plugins'][sanitize_key(strip_tags($plugin_name))] = [
  			'label' => $plugin_name,
  			'label_export' => strip_tags($plugin_data['Title']),
  			'result' => $plugin,
  			'result_export' => $plugin_data['Version'],
  		];
  	}
  }

  if (isset($sections['plugins'])) {
  	rsort($sections['plugins']);
  }

  /**
   * Server Environment
   * ==================
   */

  if (version_compare(PHP_VERSION, '7.0', '<')) {
  	$php =
  		'<mark>' .
  		PHP_VERSION .
  		' - ' .
  		__('WordPress.org recommends upgrading to PHP 7 or higher for better security.', 'google-calendar-events') .
  		' <a href="https://wordpress.org/about/requirements/" target="_blank">' .
  		__('Read more.', 'google-calendar-events') .
  		'</a>' .
  		'</mark>';
  } else {
  	$php = '<mark class="ok">' . PHP_VERSION . '</mark>';
  }

  if ($wpdb->use_mysqli) {
  	$mysql = @mysqli_get_server_info($wpdb->dbh);
  } else {
  	$mysql = '<mark class="error">' . __('Cannot connect to MySQL database.', 'google-calendar-events') . '</mark>';
  }

  $host = $_SERVER['SERVER_SOFTWARE'];
  if (defined('WPE_APIKEY')) {
  	$host .= ' (WP Engine)';
  } elseif (defined('PAGELYBIN')) {
  	$host .= ' (Pagely)';
  }

  $default_timezone = $server_timezone_export = date_default_timezone_get();
  if ('UTC' !== $default_timezone) {
  	$server_timezone =
  		'<mark class="error">' .
  		sprintf(__('Server default timezone is %s - it should be UTC', 'google-calendar-events'), $default_timezone) .
  		'</mark>';
  } else {
  	$server_timezone = '<mark class="ok">UTC</mark>';
  }

  // WP Remote POST test.
  $response = wp_safe_remote_post('https://www.paypal.com/cgi-bin/webscr', [
  	'timeout' => 60,
  	'body' => [
  		'cmd' => '_notify-validate',
  	],
  ]);
  if (!is_wp_error($response) && $response['response']['code'] >= 200 && $response['response']['code'] < 300) {
  	$wp_post_export = 'Yes';
  	$wp_post = '<mark class="ok">' . __('Yes', 'google-calendar-events') . '</mark>';
  } else {
  	$wp_post_export = 'No';
  	$wp_post = '<mark class="error">' . __('No', 'google-calendar-events');
  	if (is_wp_error($response)) {
  		$error = ' (' . $response->get_error_message() . ')';
  		$wp_post .= $error;
  		$wp_post_export .= $error;
  	} else {
  		$error = ' (' . $response['response']['code'] . ')';
  		$wp_post .= $error;
  		$wp_post_export .= $error;
  	}
  	$wp_post .= '</mark>';
  }

  // WP Remote GET test.
  $response = wp_safe_remote_get(get_home_url('/?p=1'));
  if (!is_wp_error($response) && $response['response']['code'] >= 200 && $response['response']['code'] < 300) {
  	$wp_get_export = 'Yes';
  	$wp_get = '<mark class="ok">' . __('Yes', 'google-calendar-events') . '</mark>';
  } else {
  	$wp_get_export = 'No';
  	$wp_get = '<mark class="error">' . __('No', 'google-calendar-events');
  	if (is_wp_error($response)) {
  		$error = ' (' . $response->get_error_message() . ')';
  		$wp_get .= $error;
  		$wp_get_export .= $error;
  	} else {
  		$error = ' (' . $response['response']['code'] . ')';
  		$wp_get .= $error;
  		$wp_get_export .= $error;
  	}
  	$wp_get .= '</mark>';
  }

  $php_memory_limit = ini_get('memory_limit');
  $php_max_upload_filesize = ini_get('upload_max_filesize');
  $php_post_max_size = ini_get('post_max_size');
  $php_max_execution_time = ini_get('max_execution_time');
  $php_max_input_vars = ini_get('max_input_vars');

  $curl_info = '';

  if (function_exists('curl_version')) {
  	$curl_info = curl_version();
  }

  $sections['server'] = [
  	'host' => [
  		'label' => __('Web Server', 'google-calendar-events'),
  		'label_export' => 'Web Server',
  		'result' => $host,
  	],
  	'php_version' => [
  		'label' => __('PHP Version', 'google-calendar-events'),
  		'label_export' => 'PHP Version',
  		'result' => $php,
  		'result_export' => PHP_VERSION,
  	],
  	'mysql_version' => [
  		'label' => __('MySQL Version', 'google-calendar-events'),
  		'label_export' => 'MySQL Version',
  		'result' => version_compare($mysql, '5.5', '>') ? '<mark class="ok">' . $mysql . '</mark>' : $mysql,
  		'result_export' => $mysql,
  	],
  	'server_timezone' => [
  		'label' => __('Server Timezone', 'google-calendar-events'),
  		'label_export' => 'Server Timezone',
  		'result' => $server_timezone,
  		'result_export' => $server_timezone_export,
  	],
  	'display_errors' => [
  		'label' => 'Display Errors',
  		'result' => ini_get('display_errors')
  			? __('Yes', 'google-calendar-events') . ' (' . ini_get('display_errors') . ')'
  			: '-',
  		'result_export' => ini_get('display_errors') ? 'Yes' : 'No',
  	],
  	'php_memory_limit' => [
  		'label' => 'Memory Limit',
  		'result' => $php_memory_limit ? $php_memory_limit : '-',
  	],
  	'upload_max_filesize' => [
  		'label' => 'Upload Max Filesize',
  		'result' => $php_max_upload_filesize ? $php_max_upload_filesize : '-',
  	],
  	'post_max_size' => [
  		'label' => 'Post Max Size',
  		'result' => $php_post_max_size ? $php_post_max_size : '-',
  	],
  	'max_execution_time' => [
  		'label' => 'Max Execution Time',
  		'result' => $php_max_execution_time ? $php_max_execution_time : '-',
  	],
  	'max_input_vars' => [
  		'label' => 'Max Input Vars',
  		'result' => $php_max_input_vars ? $php_max_input_vars : '-',
  	],
  	'fsockopen' => [
  		'label' => 'fsockopen',
  		'result' => function_exists('fsockopen')
  			? __('Yes', 'google-calendar-events')
  			: __('No', 'google-calendar-events'),
  		'result_export' => function_exists('fsockopen') ? 'Yes' : 'No',
  	],
  	'curl_init' => [
  		'label' => 'cURL',
  		'result' => !empty($curl_info)
  			? $curl_info['version'] . ', ' . $curl_info['ssl_version']
  			: __('No version found.', 'google-calendar-events'),
  		'result_export' => !empty($curl_info)
  			? $curl_info['version'] . ', ' . $curl_info['ssl_version']
  			: 'No version found.',
  	],
  	'soap' => [
  		'label' => 'SOAP',
  		'result' => class_exists('SoapClient') ? __('Yes', 'google-calendar-events') : __('No', 'google-calendar-events'),
  		'result_export' => class_exists('SoapClient') ? 'Yes' : 'No',
  	],
  	'suhosin' => [
  		'label' => 'SUHOSIN',
  		'result' => extension_loaded('suhosin')
  			? __('Yes', 'google-calendar-events')
  			: __('No', 'google-calendar-events'),
  		'result_export' => extension_loaded('suhosin') ? 'Yes' : 'No',
  	],
  	'wp_remote_post' => [
  		'label' => 'WP Remote POST',
  		'result' => $wp_post,
  		'result_export' => $wp_post_export,
  	],
  	'wp_remote_get' => [
  		'label' => 'WP Remote GET',
  		'result' => $wp_get,
  		'result_export' => $wp_get_export,
  	],
  ];

  /**
   * Client Information
   * ==================
   */

  $user_client = new \SimpleCalendar\Browser();

  $browser = '<dl>';
  $browser .= '<dt>' . __('Name:', 'google-calendar-events') . '</dt>';
  $browser .= '<dd>' . $user_client->getBrowser() . '</dd>';
  $browser .= '<dt>' . __('Version:', 'google-calendar-events') . '</dt>';
  $browser .= '<dd>' . $user_client->getVersion() . '</dd>';
  $browser .= '<dt>' . __('User Agent:', 'google-calendar-events') . '</dt>';
  $browser .= '<dd>' . $user_client->getUserAgent() . '</dd>';
  $browser .= '<dt>' . __('Platform:', 'google-calendar-events') . '</dt>';
  $browser .= '<dd>' . $user_client->getPlatform() . '</dd>';
  $browser .= '</dl>';

  $browser_export =
  	$user_client->getBrowser() . ' ' . $user_client->getVersion() . ' (' . $user_client->getPlatform() . ')';

  $sections['client'] = [
  	'user_ip' => [
  		'label' => __('IP Address', 'google-calendar-events'),
  		'label_export' => 'IP Address',
  		'result' => $_SERVER['SERVER_ADDR'],
  	],
  	'browser' => [
  		'label' => __('Browser', 'google-calendar-events'),
  		'result' => $browser,
  		'result_export' => $browser_export,
  	],
  ];

  /**
   * Final Output
   * ============
   */

  $panels = apply_filters('simcal_system_status_report_panels', $panels);
  $sections = apply_filters('simcal_system_status_report_sections', $sections);

  foreach ($panels as $panel => $v):
  	if (isset($sections[$panel])): ?>
				<table class="widefat simcal-system-status-report-panel">
					<thead class="<?php echo $panel; ?>">
						<tr>
							<th colspan="3" data-export="<?php echo $v['export']; ?>"><?php echo $v['label']; ?></th>
						</tr>
					</thead>
					<tbody>
						<?php foreach ($sections[$panel] as $row => $cell): ?>
							<tr>
								<?php
        $label_export = isset($cell['label_export']) ? $cell['label_export'] : $cell['label'];
        $result_export = isset($cell['result_export']) ? $cell['result_export'] : $cell['result'];
        ?>
								<td class="tooltip"><?php echo isset($cell['tooltip'])
        	? ' <i class="simcal-icon-help simcal-help-tip" data-tip="' . $cell['tooltip'] . '"></i> '
        	: ''; ?></td>
								<td class="label" data-export="<?php echo trim($label_export); ?>"><?php echo $cell['label']; ?></td>
								<td class="result" data-export="<?php echo trim($result_export); ?>"><?php echo $cell['result']; ?></td>
							</tr>
						<?php endforeach; ?>
					</tbody>
				</table>
				<?php endif;
  endforeach;

  $this->inline_scripts();
	}

	/**
	 * Print inline scripts.
	 *
	 * @since  3.0.0
	 * @access private
	 *
	 * @return void
	 */
	private function inline_scripts()
	{
		?>
		<script type="text/javascript">

			var report = '';

			jQuery( '.simcal-system-status-report-panel thead, .simcal-system-status-report-panel tbody' ).each( function() {

				if ( jQuery( this ).is( 'thead' ) ) {

					var label = jQuery( this ).find( 'th' ).data( 'export' );
					report = report + '\n### ' + jQuery.trim( label ) + ' ###\n\n';

				} else {

					jQuery( 'tr', jQuery( this ) ).each( function() {

						var label       = jQuery( this ).find( 'td:eq(1)' ).data( 'export' );
						var the_name    = jQuery.trim( label ).replace( /(<([^>]+)>)/ig, '' ); // Remove HTML
						var image       = jQuery( this ).find( 'td:eq(2)' ).find( 'img' ); // Get WP 4.2 emojis
						var prefix      = ( undefined === image.attr( 'alt' ) ) ? '' : image.attr( 'alt' ) + ' '; // Remove WP 4.2 emojis
						var the_value   = jQuery.trim( prefix + jQuery( this ).find( 'td:eq(2)' ).data( 'export' ) );
						var value_array = the_value.split( ', ' );
						if ( value_array.length > 1 ) {
							var temp_line ='';
							jQuery.each( value_array, function( key, line ) {
								temp_line = temp_line + line + '\n';
							});
							the_value = temp_line;
						}

						report = report + '' + the_name.trim() + ': ' + the_value.trim() + '\n';
					});

				}

			});

			try {
				jQuery( '#simcal-system-status-report textarea' ).val( report ).focus().select();
			} catch( e ){
				console.log( e );
			}

			function downloadReport( text, name, type ) {
				var a = document.getElementById( 'simcal-system-status-report-download' );
				var file = new Blob( [text], { type: type } );
				a.href = URL.createObjectURL(file);
				a.download = name;
			}

			jQuery( '#simcal-system-status-report-download' ).on( 'click', function() {
				var file = new Blob( [ report ], { type: 'text/plain' } );
				jQuery( this ).attr( 'href', URL.createObjectURL( file ) );
				jQuery( this ).attr( 'download', '<?php echo sanitize_title(
    	str_replace(['http://', 'https://'], '', get_bloginfo('url')) . '-system-report-' . date('Y-m-d', time()),
    ); ?>' );
			} );

		</script>
		<?php
	}

	/**
	 * PHP sizes conversions.
	 *
	 * This function transforms the php.ini notation for numbers (like '2M') to an integer.
	 *
	 * @since  3.0.0
	 * @access private
	 *
	 * @param  string $size
	 *
	 * @return int|double|string
	 */
	private function let_to_num($size)
	{
		$l = substr($size, -1);
		$ret = substr($size, 0, -1);

		// Note: do not insert break or default in this switch loop.
		switch (strtoupper($l)) {
			case 'P':
				$ret *= 1024;
			// no break
			case 'T':
				$ret *= 1024;
			// no break
			case 'G':
				$ret *= 1024;
			// no break
			case 'M':
				$ret *= 1024;
			// no break
			case 'K':
				$ret *= 1024;
			// no break
		}

		return $ret;
	}

	/**
	 * Add sections.
	 *
	 * @since  3.0.0
	 *
	 * @return array
	 */
	public function add_sections()
	{
		return [];
	}

	/**
	 * Add fields.
	 *
	 * @since  3.0.0
	 *
	 * @return array
	 */
	public function add_fields()
	{
		return [];
	}
}
