<?php
/**
 * @package     Joomla.Platform
 * @subpackage  Mail
 *
 * @copyright   Copyright (C) 2005 - 2011 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE
 */

defined('JPATH_PLATFORM') or die;

/**
 * Email helper class, provides static methods to perform various tasks relevant
 * to the Joomla email routines.
 *
 * TODO: Test these methods as the regex work is first run and not tested thoroughly
 *
 * @static
 * @package     Joomla.Platform
 * @subpackage  Mail
 * @since       11.1
 */
abstract class JMailHelper
{
    /**
     * Cleans single line inputs.
     *
     * @static
     * @param   string  $value  String to be cleaned.
     * @return  string  Cleaned string.
     */
    public static function cleanLine($value)
    {
        return trim(preg_replace('/(%0A|%0D|\n+|\r+)/i', '', $value));
    }

    /**
     * Cleans multi-line inputs.
     *
     * @static
     * @param   string  $value  Multi-line string to be cleaned.
     * @return  string  Cleaned multi-line string.
     */
    public static function cleanText($value)
    {
        return trim(preg_replace('/(%0A|%0D|\n+|\r+)(content-type:|to:|cc:|bcc:)/i', '', $value));
    }

    /**
     * Cleans any injected headers from the email body.
     *
     * @static
     * @param   string  $body   email body string.
     * @return  string  Cleaned email body string.
     * @since   11.1
     */
    public static function cleanBody($body)
    {
        // Strip all email headers from a string
        return preg_replace("/((From:|To:|Cc:|Bcc:|Subject:|Content-type:) ([\S]+))/", "", $body);
    }

    /**
     * Cleans any injected headers from the subject string.
     *
     * @static
     * @param   string  $subject    email subject string.
     * @return  string  Cleaned email subject string.
     * @since   11.1
     */
    public static function cleanSubject($subject)
    {
        return preg_replace("/((From:|To:|Cc:|Bcc:|Content-type:) ([\S]+))/", "", $subject);
    }

    /**
     * Verifies that an email address does not have any extra headers injected into it.
     *
     * @static
     * @param   string  $address    email address.
     * @return  string|false    email address string or boolean false if injected headers are present.
     * @since   11.1
     */
    public static function cleanAddress($address)
    {
        if (preg_match("[\s;,]", $address)) {
            return false;
        }
        return $address;
    }

    /**
     * Verifies that the string is in a proper email address format.
     *
     * @static
     * @param   string  $email  String to be verified.
     * @return  boolean True if string has the correct format; false otherwise.
     * @since   11.1
     */
    public static function isEmailAddress($email)
    {
        // Split the email into a local and domain
        $atIndex    = strrpos($email, "@");
        $domain     = substr($email, $atIndex+1);
        $local      = substr($email, 0, $atIndex);

        // Check Length of domain
        $domainLen  = strlen($domain);
        if ($domainLen < 1 || $domainLen > 255) {
            return false;
        }

        // Check the local address
        // We're a bit more conservative about what constitutes a "legal" address, that is, A-Za-z0-9!#$%&\'*+/=?^_`{|}~-
        // Also, the last character in local cannot be a period ('.')
        $allowed    = 'A-Za-z0-9!#&*+=?_-';
        $regex      = "/^[$allowed][\.$allowed]{0,63}$/";
        if (!preg_match($regex, $local) || substr($local, -1) == '.') {
            return false;
        }

        // No problem if the domain looks like an IP address, ish
        $regex      = '/^[0-9\.]+$/';
        if (preg_match($regex, $domain)) {
            return true;
        }

        // Check Lengths
        $localLen   = strlen($local);
        if ($localLen < 1 || $localLen > 64) {
            return false;
        }

        // Check the domain
        $domain_array   = explode(".", rtrim($domain, '.'));
        $regex      = '/^[A-Za-z0-9-]{0,63}$/';
        foreach ($domain_array as $domain) {

            // Must be something
            if (!$domain) {
                return false;
            }

            // Check for invalid characters
            if (!preg_match($regex, $domain)) {
                return false;
            }

            // Check for a dash at the beginning of the domain
            if (strpos($domain, '-') === 0) {
                return false;
            }

            // Check for a dash at the end of the domain
            $length = strlen($domain) -1;
            if (strpos($domain, '-', $length) === $length) {
                return false;
            }
        }

        return true;
    }
}