<?php

namespace Box\Spout\Reader\ODS\Helper;

use Box\Spout\Reader\Exception\XMLProcessingException;
use Box\Spout\Reader\Wrapper\XMLReader;

/**
 * Class SettingsHelper
 * This class provides helper functions to extract data from the "settings.xml" file.
 *
 * @package Box\Spout\Reader\ODS\Helper
 */
class SettingsHelper {

	const SETTINGS_XML_FILE_PATH = 'settings.xml';

	/** Definition of XML nodes name and attribute used to parse settings data */
	const XML_NODE_CONFIG_ITEM             = 'config:config-item';
	const XML_ATTRIBUTE_CONFIG_NAME        = 'config:name';
	const XML_ATTRIBUTE_VALUE_ACTIVE_TABLE = 'ActiveTable';

	/**
	 * @param string $filePath Path of the file to be read
	 * @return string|null Name of the sheet that was defined as active or NULL if none found
	 */
	public function getActiveSheetName( $filePath ) {
		$xmlReader = new XMLReader();
		if ( $xmlReader->openFileInZip( $filePath, self::SETTINGS_XML_FILE_PATH ) === false ) {
			return null;
		}

		$activeSheetName = null;

		try {
			while ( $xmlReader->readUntilNodeFound( self::XML_NODE_CONFIG_ITEM ) ) {
				if ( $xmlReader->getAttribute( self::XML_ATTRIBUTE_CONFIG_NAME ) === self::XML_ATTRIBUTE_VALUE_ACTIVE_TABLE ) {
					$activeSheetName = $xmlReader->readString();
					break;
				}
			}
		} catch ( XMLProcessingException $exception ) {
			// do nothing
		}

		$xmlReader->close();

		return $activeSheetName;
	}
}