<?php

namespace Box\Spout\Common\Escaper;

use Box\Spout\Common\Singleton;

/**
 * Class ODS
 * Provides functions to escape and unescape data for ODS files
 *
 * @package Box\Spout\Common\Escaper
 */
class ODS implements EscaperInterface {

	use Singleton;

	/**
	 * Escapes the given string to make it compatible with XLSX
	 *
	 * @param string $string The string to escape
	 * @return string The escaped string
	 */
	public function escape( $string ) {
		if ( defined( 'ENT_DISALLOWED' ) ) {
			// 'ENT_DISALLOWED' ensures that invalid characters in the given document type are replaced.
			// Otherwise control characters like a vertical tab "\v" will make the XML document unreadable by the XML processor
			// @link https://github.com/box/spout/issues/329
			$replacedString = htmlspecialchars( $string, ENT_NOQUOTES | ENT_DISALLOWED );
		} else {
			// We are on hhvm or any other engine that does not support ENT_DISALLOWED.
			//
			// @NOTE: Using ENT_NOQUOTES as only XML entities ('<', '>', '&') need to be encoded.
			//        Single and double quotes can be left as is.
			$escapedString = htmlspecialchars( $string, ENT_NOQUOTES );

			// control characters values are from 0 to 1F (hex values) in the ASCII table
			// some characters should not be escaped though: "\t", "\r" and "\n".
			$regexPattern = '[\x00-\x08' .
						// skipping "\t" (0x9) and "\n" (0xA)
						'\x0B-\x0C' .
						// skipping "\r" (0xD)
						'\x0E-\x1F]';
			$replacedString = preg_replace( "/$regexPattern/", '�', $escapedString );
		}

		return $replacedString;
	}

	/**
	 * Unescapes the given string to make it compatible with XLSX
	 *
	 * @param string $string The string to unescape
	 * @return string The unescaped string
	 */
	public function unescape( $string ) {
		// ==============
		// =   WARNING  =
		// ==============
		// It is assumed that the given string has already had its XML entities decoded.
		// This is true if the string is coming from a DOMNode (as DOMNode already decode XML entities on creation).
		// Therefore there is no need to call "htmlspecialchars_decode()".
		return $string;
	}
}