<?php
/**
 * PEAR's Mail:: interface.
 *
 * PHP version 5
 *
 * LICENSE:
 *
 * Copyright (c) 1997-2017, Chuck Hagenbuch & Richard Heyes
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @category    Mail
 * @package     Mail
 * @author      Chuck Hagenbuch <chuck@horde.org>
 * @copyright   1997-2017 Chuck Hagenbuch
 * @license     http://opensource.org/licenses/BSD-3-Clause New BSD License
 * @version     CVS: $Id$
 * @link        http://pear.php.net/package/Mail/
 */

require_once 'PEAR.php';

/**
 * PEAR's Mail:: interface. Defines the interface for implementing
 * mailers under the PEAR hierarchy, and provides supporting functions
 * useful in multiple mailer backends.
 *
 * @version $Revision$
 * @package Mail
 */
class Mail
{
    /**
     * Line terminator used for separating header lines.
     * @var string
     */
    public $sep = "\r\n";

    /**
     * Provides an interface for generating Mail:: objects of various
     * types
     *
     * @param string $driver The kind of Mail:: object to instantiate.
     * @param array  $params The parameters to pass to the Mail:: object.
     *
     * @return object Mail a instance of the driver class or if fails a PEAR Error
     */
    public static function factory($driver, $params = array())
    {
        $driver = strtolower($driver);
        @include_once 'Mail/' . $driver . '.php';
        $class = 'Mail_' . $driver;
        if (class_exists($class)) {
            $mailer = new $class($params);
            return $mailer;
        } else {
            return PEAR::raiseError('Unable to find class for driver ' . $driver);
        }
    }

    /**
     * Implements Mail::send() function using php's built-in mail()
     * command.
     *
     * @param mixed $recipients Either a comma-seperated list of recipients
     *              (RFC822 compliant), or an array of recipients,
     *              each RFC822 valid. This may contain recipients not
     *              specified in the headers, for Bcc:, resending
     *              messages, etc.
     *
     * @param array $headers The array of headers to send with the mail, in an
     *              associative array, where the array key is the
     *              header name (ie, 'Subject'), and the array value
     *              is the header value (ie, 'test'). The header
     *              produced from those values would be 'Subject:
     *              test'.
     *
     * @param string $body The full text of the message body, including any
     *               Mime parts, etc.
     *
     * @return mixed Returns true on success, or a PEAR_Error
     *               containing a descriptive error message on
     *               failure.
     *
     * @deprecated use Mail_mail::send instead
     */
    public function send($recipients, $headers, $body)
    {
        if (!is_array($headers)) {
            return PEAR::raiseError('$headers must be an array');
        }

        $result = $this->_sanitizeHeaders($headers);
        if (is_a($result, 'PEAR_Error')) {
            return $result;
        }

        // if we're passed an array of recipients, implode it.
        if (is_array($recipients)) {
            $recipients = implode(', ', $recipients);
        }

        // get the Subject out of the headers array so that we can
        // pass it as a seperate argument to mail().
        $subject = '';
        if (isset($headers['Subject'])) {
            $subject = $headers['Subject'];
            unset($headers['Subject']);
        }

        // flatten the headers out.
        list(, $text_headers) = Mail::prepareHeaders($headers);

        return mail($recipients, $subject, $body, $text_headers);
    }

    /**
     * Sanitize an array of mail headers by removing any additional header
     * strings present in a legitimate header's value.  The goal of this
     * filter is to prevent mail injection attacks.
     *
     * @param array $headers The associative array of headers to sanitize.
     */
    protected function _sanitizeHeaders(&$headers)
    {
        foreach ($headers as $key => $value) {
            $headers[$key] =
                preg_replace('=((<CR>|<LF>|0x0A/%0A|0x0D/%0D|\\n|\\r)\S).*=i',
                             '', $value);
        }
    }

    /**
     * Take an array of mail headers and return a string containing
     * text usable in sending a message.
     *
     * @param array $headers The array of headers to prepare, in an associative
     *              array, where the array key is the header name (ie,
     *              'Subject'), and the array value is the header
     *              value (ie, 'test'). The header produced from those
     *              values would be 'Subject: test'.
     *
     * @return mixed Returns false if it encounters a bad address,
     *               otherwise returns an array containing two
     *               elements: Any From: address found in the headers,
     *               and the plain text version of the headers.
     */
    protected function prepareHeaders($headers)
    {
        $lines = array();
        $from = null;

        foreach ($headers as $key => $value) {
            if (strcasecmp($key, 'From') === 0) {
                include_once 'Mail/RFC822.php';
                $parser = new Mail_RFC822();
                $addresses = $parser->parseAddressList($value, 'localhost', false);
                if (is_a($addresses, 'PEAR_Error')) {
                    return $addresses;
                }

                $from = $addresses[0]->mailbox . '@' . $addresses[0]->host;

                // Reject envelope From: addresses with spaces.
                if (strstr($from, ' ')) {
                    return false;
                }

                $lines[] = $key . ': ' . $value;
            } elseif (strcasecmp($key, 'Received') === 0) {
                $received = array();
                if (is_array($value)) {
                    foreach ($value as $line) {
                        $received[] = $key . ': ' . $line;
                    }
                }
                else {
                    $received[] = $key . ': ' . $value;
                }
                // Put Received: headers at the top.  Spam detectors often
                // flag messages with Received: headers after the Subject:
                // as spam.
                $lines = array_merge($received, $lines);
            } else {
                // If $value is an array (i.e., a list of addresses), convert
                // it to a comma-delimited string of its elements (addresses).
                if (is_array($value)) {
                    $value = implode(', ', $value);
                }
                $lines[] = $key . ': ' . $value;
            }
        }

        return array($from, join($this->sep, $lines));
    }

    /**
     * Take a set of recipients and parse them, returning an array of
     * bare addresses (forward paths) that can be passed to sendmail
     * or an smtp server with the rcpt to: command.
     *
     * @param mixed Either a comma-seperated list of recipients
     *              (RFC822 compliant), or an array of recipients,
     *              each RFC822 valid.
     *
     * @return mixed An array of forward paths (bare addresses) or a PEAR_Error
     *               object if the address list could not be parsed.
     */
    protected function parseRecipients($recipients)
    {
        include_once 'Mail/RFC822.php';

        // if we're passed an array, assume addresses are valid and
        // implode them before parsing.
        if (is_array($recipients)) {
            $recipients = implode(', ', $recipients);
        }

        // Parse recipients, leaving out all personal info. This is
        // for smtp recipients, etc. All relevant personal information
        // should already be in the headers.
        $Mail_RFC822 = new Mail_RFC822();
        $addresses = $Mail_RFC822->parseAddressList($recipients, 'localhost', false);

        // If parseAddressList() returned a PEAR_Error object, just return it.
        if (is_a($addresses, 'PEAR_Error')) {
            return $addresses;
        }

        $recipients = array();
        if (is_array($addresses)) {
            foreach ($addresses as $ob) {
                $recipients[] = $ob->mailbox . '@' . $ob->host;
            }
        }

        return $recipients;
    }

}
