<?php

/*
 +-----------------------------------------------------------------------+
 | program/include/rcube_smtp.php                                        |
 |                                                                       |
 | This file is part of the Roundcube Webmail client                     |
 | Copyright (C) 2005-2010, The Roundcube Dev Team                       |
 |                                                                       |
 | Licensed under the GNU General Public License version 3 or            |
 | any later version with exceptions for skins & plugins.                |
 | See the README file for a full license statement.                     |
 |                                                                       |
 | PURPOSE:                                                              |
 |   Provide SMTP functionality using socket connections                 |
 |                                                                       |
 +-----------------------------------------------------------------------+
 | Author: Thomas Bruederli <roundcube@gmail.com>                        |
 +-----------------------------------------------------------------------+

 $Id$

*/

// define headers delimiter
define('SMTP_MIME_CRLF', "\r\n");

/**
 * Class to provide SMTP functionality using PEAR Net_SMTP
 *
 * @package    Mail
 * @author     Thomas Bruederli <roundcube@gmail.com>
 * @author     Aleksander Machniak <alec@alec.pl>
 */
class rcube_smtp
{

  private $conn = null;
  private $response;
  private $error;


  /**
   * SMTP Connection and authentication
   *
   * @param string Server host
   * @param string Server port
   * @param string User name
   * @param string Password
   *
   * @return bool  Returns true on success, or false on error
   */
  public function connect($host=null, $port=null, $user=null, $pass=null)
  {
    $RCMAIL = rcmail::get_instance();

    // disconnect/destroy $this->conn
    $this->disconnect();

    // reset error/response var
    $this->error = $this->response = null;

    // let plugins alter smtp connection config
    $CONFIG = $RCMAIL->plugins->exec_hook('smtp_connect', array(
      'smtp_server'    => $host ? $host : $RCMAIL->config->get('smtp_server'),
      'smtp_port'      => $port ? $port : $RCMAIL->config->get('smtp_port', 25),
      'smtp_user'      => $user ? $user : $RCMAIL->config->get('smtp_user'),
      'smtp_pass'      => $pass ? $pass : $RCMAIL->config->get('smtp_pass'),
      'smtp_auth_cid'  => $RCMAIL->config->get('smtp_auth_cid'),
      'smtp_auth_pw'   => $RCMAIL->config->get('smtp_auth_pw'),
      'smtp_auth_type' => $RCMAIL->config->get('smtp_auth_type'),
      'smtp_helo_host' => $RCMAIL->config->get('smtp_helo_host'),
      'smtp_timeout'   => $RCMAIL->config->get('smtp_timeout'),
      'smtp_auth_callbacks' => array(),
    ));

    $smtp_host = rcube_parse_host($CONFIG['smtp_server']);
    // when called from Installer it's possible to have empty $smtp_host here
    if (!$smtp_host) $smtp_host = 'localhost';
    $smtp_port = is_numeric($CONFIG['smtp_port']) ? $CONFIG['smtp_port'] : 25;
    $smtp_host_url = parse_url($smtp_host);

    // overwrite port
    if (isset($smtp_host_url['host']) && isset($smtp_host_url['port']))
    {
      $smtp_host = $smtp_host_url['host'];
      $smtp_port = $smtp_host_url['port'];
    }

    // re-write smtp host
    if (isset($smtp_host_url['host']) && isset($smtp_host_url['scheme']))
      $smtp_host = sprintf('%s://%s', $smtp_host_url['scheme'], $smtp_host_url['host']);

    // remove TLS prefix and set flag for use in Net_SMTP::auth()
    if (preg_match('#^tls://#i', $smtp_host)) {
      $smtp_host = preg_replace('#^tls://#i', '', $smtp_host);
      $use_tls = true;
    }

    if (!empty($CONFIG['smtp_helo_host']))
      $helo_host = $CONFIG['smtp_helo_host'];
    else if (!empty($_SERVER['SERVER_NAME']))
      $helo_host = preg_replace('/:\d+$/', '', $_SERVER['SERVER_NAME']);
    else
      $helo_host = 'localhost';

    // IDNA Support
    $smtp_host = rcube_idn_to_ascii($smtp_host);

    $options = [
        'ssl' => [
	    'verify_peer_name' => false,
	    'verify_peer' => false,
	    'allow_self_signed' => true,
	],
    ];

    $this->conn = new Net_SMTP($smtp_host, $smtp_port, $helo_host, false, 10, $options);

    if ($RCMAIL->config->get('smtp_debug'))
      $this->conn->setDebug(true, array($this, 'debug_handler'));

    // register authentication methods
    if (!empty($CONFIG['smtp_auth_callbacks']) && method_exists($this->conn, 'setAuthMethod')) {
      foreach ($CONFIG['smtp_auth_callbacks'] as $callback) {
        $this->conn->setAuthMethod($callback['name'], $callback['function'],
          isset($callback['prepend']) ? $callback['prepend'] : true);
      }
    }

    // try to connect to server and exit on failure
    $result = $this->conn->connect($smtp_timeout);

    if (PEAR::isError($result)) {
      $this->response[] = "Connection failed: ".$result->getMessage();
      $this->error = array('label' => 'smtpconnerror', 'vars' => array('code' => $this->conn->_code));
      $this->conn = null;
      return false;
    }

    // workaround for timeout bug in Net_SMTP 1.5.[0-1] (#1487843)
    if (method_exists($this->conn, 'setTimeout')
      && ($timeout = ini_get('default_socket_timeout'))
    ) {
      $this->conn->setTimeout($timeout);
    }

    $smtp_user = str_replace('%u', $_SESSION['username'], $CONFIG['smtp_user']);
    $smtp_pass = str_replace('%p', $RCMAIL->decrypt($_SESSION['password']), $CONFIG['smtp_pass']);
    $smtp_auth_type = empty($CONFIG['smtp_auth_type']) ? NULL : $CONFIG['smtp_auth_type'];

    if (!empty($CONFIG['smtp_auth_cid'])) {
      $smtp_authz = $smtp_user;
      $smtp_user  = $CONFIG['smtp_auth_cid'];
      $smtp_pass  = $CONFIG['smtp_auth_pw'];
    }

    // attempt to authenticate to the SMTP server
    if ($smtp_user && $smtp_pass)
    {
      // IDNA Support
      if (strpos($smtp_user, '@')) {
        $smtp_user = rcube_idn_to_ascii($smtp_user);
      }

      $result = $this->conn->auth($smtp_user, $smtp_pass, $smtp_auth_type, $use_tls, $smtp_authz);

      if (PEAR::isError($result))
      {
        $this->error = array('label' => 'smtpautherror', 'vars' => array('code' => $this->conn->_code));
        $this->response[] .= 'Authentication failure: ' . $result->getMessage() . ' (Code: ' . $result->getCode() . ')';
        $this->reset();
        $this->disconnect();
        return false;
      }
    }

    return true;
  }


  /**
   * Function for sending mail
   *
   * @param string Sender e-Mail address
   *
   * @param mixed  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 mixed  The message headers to send with the mail
   *               Either as an associative array or a finally
   *               formatted string
   * @param mixed  The full text of the message body, including any Mime parts
   *               or file handle
   * @param array  Delivery options (e.g. DSN request)
   *
   * @return bool  Returns true on success, or false on error
   */
  public function send_mail($from, $recipients, &$headers, &$body, $opts=null)
  {
    if (!is_object($this->conn))
      return false;

    // prepare message headers as string
    if (is_array($headers))
    {
      if (!($headerElements = $this->_prepare_headers($headers))) {
        $this->reset();
        return false;
      }

      list($from, $text_headers) = $headerElements;
    }
    else if (is_string($headers))
      $text_headers = $headers;
    else
    {
      $this->reset();
      $this->response[] = "Invalid message headers";
      return false;
    }

    // exit if no from address is given
    if (!isset($from))
    {
      $this->reset();
      $this->response[] = "No From address has been provided";
      return false;
    }

    // RFC3461: Delivery Status Notification
    if ($opts['dsn']) {
      $exts = $this->conn->getServiceExtensions();

      if (isset($exts['DSN'])) {
        $from_params      = 'RET=HDRS';
        $recipient_params = 'NOTIFY=SUCCESS,FAILURE';
      }
    }

    // RFC2298.3: remove envelope sender address
    if (preg_match('/Content-Type: multipart\/report/', $text_headers)
      && preg_match('/report-type=disposition-notification/', $text_headers)
    ) {
      $from = '';
    }

    // set From: address
    if (PEAR::isError($this->conn->mailFrom($from, $from_params)))
    {
      $err = $this->conn->getResponse();
      $this->error = array('label' => 'smtpfromerror', 'vars' => array(
        'from' => $from, 'code' => $this->conn->_code, 'msg' => $err[1]));
      $this->response[] = "Failed to set sender '$from'";
      $this->reset();
      return false;
    }

    // prepare list of recipients
    $recipients = $this->_parse_rfc822($recipients);
    if (PEAR::isError($recipients))
    {
      $this->error = array('label' => 'smtprecipientserror');
      $this->reset();
      return false;
    }

    // set mail recipients
    foreach ($recipients as $recipient)
    {
      if (PEAR::isError($this->conn->rcptTo($recipient, $recipient_params))) {
        $err = $this->conn->getResponse();
        $this->error = array('label' => 'smtptoerror', 'vars' => array(
          'to' => $recipient, 'code' => $this->conn->_code, 'msg' => $err[1]));
        $this->response[] = "Failed to add recipient '$recipient'";
        $this->reset();
        return false;
      }
    }

    if (is_resource($body))
    {
      // file handle
      $data = $body;
      $text_headers = preg_replace('/[\r\n]+$/', '', $text_headers);
    } else {
      // Concatenate headers and body so it can be passed by reference to SMTP_CONN->data
      // so preg_replace in SMTP_CONN->quotedata will store a reference instead of a copy. 
      // We are still forced to make another copy here for a couple ticks so we don't really 
      // get to save a copy in the method call.
      $data = $text_headers . "\r\n" . $body;

      // unset old vars to save data and so we can pass into SMTP_CONN->data by reference.
      unset($text_headers, $body);
    }

    // Send the message's headers and the body as SMTP data.
    if (PEAR::isError($result = $this->conn->data($data, $text_headers)))
    {
      $err = $this->conn->getResponse();
      if (!in_array($err[0], array(354, 250, 221)))
        $msg = sprintf('[%d] %s', $err[0], $err[1]);
      else
        $msg = $result->getMessage();

      $this->error = array('label' => 'smtperror', 'vars' => array('msg' => $msg));
      $this->response[] = "Failed to send data";
      $this->reset();
      return false;
    }

    $this->response[] = join(': ', $this->conn->getResponse());
    return true;
  }


  /**
   * Reset the global SMTP connection
   * @access public
   */
  public function reset()
  {
    if (is_object($this->conn))
      $this->conn->rset();
  }


  /**
   * Disconnect the global SMTP connection
   * @access public
   */
  public function disconnect()
  {
    if (is_object($this->conn)) {
      $this->conn->disconnect();
      $this->conn = null;
    }
  }


  /**
   * This is our own debug handler for the SMTP connection
   * @access public
   */
  public function debug_handler(&$smtp, $message)
  {
    write_log('smtp', preg_replace('/\r\n$/', '', $message));
  }


  /**
   * Get error message
   * @access public
   */
  public function get_error()
  {
    return $this->error;
  }


  /**
   * Get server response messages array
   * @access public
   */
  public function get_response()
  {
    return $this->response;
  }


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

    foreach ($headers as $key => $value)
    {
      if (strcasecmp($key, 'From') === 0)
      {
        $addresses = $this->_parse_rfc822($value);

        if (is_array($addresses))
          $from = $addresses[0];

        // Reject envelope From: addresses with spaces.
        if (strpos($from, ' ') !== false)
          return false;

        $lines[] = $key . ': ' . $value;
      }
      else if (strcasecmp($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(SMTP_MIME_CRLF, $lines) . SMTP_MIME_CRLF);
  }

  /**
   * 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 array An array of forward paths (bare addresses).
   * @access private
   */
  private function _parse_rfc822($recipients)
  {
    // if we're passed an array, assume addresses are valid and implode them before parsing.
    if (is_array($recipients))
      $recipients = implode(', ', $recipients);

    $addresses = array();
    $recipients = str_replace(array("\n", "\r"), "", $recipients); 
    $recipients = rcube_explode_quoted_string(',', $recipients);

    reset($recipients);
    while (list($k, $recipient) = each($recipients))
    {
      $a = rcube_explode_quoted_string(' ', $recipient);
      while (list($k2, $word) = each($a))
      {
        if (strpos($word, "@") > 0 && $word[strlen($word)-1] != '"')
        {
          $word = preg_replace('/^<|>$/', '', trim($word));
          if (in_array($word, $addresses)===false)
            array_push($addresses, $word);
        }
      }
    }

    return $addresses;
  }

}
