<?php
/** DomFramework
    @package domframework
    @author Dominique Fournier <dominique@fournier38.fr> */

/** Allow to send mails by smtp */
class smtp
{
  /** Debug mode
    */
  public $debug = 0;
  /** The debug file used to store all the communication between the client and
    * the server. The file contains the passwords if used !
    */
  public $debugFile = "/tmp/debugSMTP";
  /** The authentication user allow to send SMTP mails
    */
  public $user = null;
  /** The authentication password allow to send SMTP mails
    */
  public $password = null;
  /** The SMTP server name or IP
    */
  public $server = "127.0.0.1";
  /** The SMTP port to use (if false, use 25 if no SSL or 465 if SSL,
    * if user defined, use the user value)
    */
  public $port = false;
  /** The SMTPS support by tunnelling the session in SSL transport
    */
  public $ssl = false;
  /** Check the certification chain in SSL mode
    */
  public $sslCheck = true;
  /** The Timeout between the answer of the SMTP server. If the server don't
    * answer in this time, an exception is raised
    */
  public $timeout = 10;
  /** Activate STARTTLS if needed. Allowed values : none, may, encrypt
    */
  public $starttls = "may";
  /** Check the certificate in STARTTLS
    */
  public $starttlsCheck = false;
  /** The authentication methods in an array. Allowed : plain, login
    */
  public $authmethods = array ("plain", "login");
  /** The socket of the connection
    */
  private $smtpStream = null;

  /** Connect to the SMTP server */
  public function connect ()
  {
    $context = array ();
    if ($this->ssl)
    {
      $this->server = "tls://$this->server";
      $context["ssl"]["verify_peer_name"] = $this->sslCheck;
      $context["ssl"]["verify_peer"] = $this->sslCheck;
      if ($this->port === false)
        $this->port = 465;
    }
    else
    {
      if ($this->port === false)
        $this->port = 25;
    }
    $mainContext = stream_context_create ($context);
    $this->debug ("####SMTP Connection to $this->server:$this->port (".
                  date ("Y/m/d H:i:s").")\n");
    ini_set('track_errors', 1);
    $this->smtpStream = @stream_socket_client ("$this->server:$this->port",
                                    $errno, $errstr,
                                    $this->timeout, STREAM_CLIENT_CONNECT,
                                    $mainContext);
    ini_set('track_errors', 0);
    if ($this->smtpStream === false)
    {
      if ($errstr === "" && $php_errormsg !== "")
        $errstr = $php_errormsg;
      throw new \Exception (sprintf (_("Can't connect to SMTP server : %s"),
                                     $errstr), 500);
    }
    stream_set_timeout ($this->smtpStream, $this->timeout);
    // Wait for banner
    $banner = $this->getLine ("SMTP Banner");
    // Send EHLO
    $features = $this->putLine ("EHLO ".gethostname ()."\r\n");
    $features = explode ("\r\n", $features);
    if (in_array ("250-STARTTLS", $features))
    {
      // Server supports STARTTLS
      if ($this->starttls === "may" || $this->starttls === "encrypt")
      {
        $this->putLine ("STARTTLS\r\n");
        $context["ssl"]["verify_peer_name"] = $this->starttlsCheck;
        $context["ssl"]["verify_peer"] = $this->starttlsCheck;
        stream_context_set_option ($this->smtpStream, $context);
        // The track_errors permit to create the $php_errormsg in case of
        // warning
        ini_set('track_errors', 1);
        if (@stream_socket_enable_crypto ($this->smtpStream, true,
                                         STREAM_CRYPTO_METHOD_TLS_CLIENT) ===
            false)
          throw new \Exception (sprintf (_("Can't activate STARTTLS %s"),
                                strstr ($php_errormsg, ": ")), 500);
        ini_set('track_errors', 0);
        $this->debug ("STARTTLS ACTIVATED\n");
      }
    }
    elseif ($this->starttls === "encrypt")
      throw new \Exception (_("Server doesn't supports STARTTLS"), 500);

    if ($this->user !== null && $this->password !== null)
    {
      $auths = preg_grep ("#^250-AUTH #", $features);
      $auths = reset ($auths);
      if (strpos ($auths, "PLAIN") && in_array ("plain", $this->authmethods))
      {
        // Send User and password AUTH PLAIN
        $this->putLine ("AUTH PLAIN ".
                        base64_encode ($this->user.chr(0).$this->user.chr(0).
                                       $this->password)."\r\n");
      }
      elseif (strpos ($auths, "LOGIN") &&
              in_array ("login", $this->authmethods))
      {
        // Send User and password AUTH LOGIN
        $this->putLine ("AUTH LOGIN ".base64_encode ($this->user)."\r\n");
        $this->putLine (base64_encode ($this->password)."\r\n");
      }
      else
        throw new \Exception (
                         _("No authentication method available for the server"),
                              500);
    }
  }

  /** Send the mail to the users
    * @param string $from The email address used for the from enveloppe
    * @param string|array $to the recipient of the email. Not displayed in the
    *        email content
    * @param string $completeMail The content of the email
    * @return the message from the server (where is stored the message queue
    * identifier
    */
  public function send ($from, $to, $completeMail)
  {
    if ($this->smtpStream === null)
      throw new \Exception (
                           _("Can't send email : not connected to SMTP server"),
                           500);
    if (is_string ($to))
      $to = array ($to);
    $this->putLine ("MAIL FROM: $from\r\n");
    foreach ($to as $t)
      $this->putLine ("RCPT TO: $t\r\n");
    $this->putLine ("DATA\r\n");
    if (substr ($completeMail, -2) !== "\r\n")
      $completeMail .= "\r\n";
    return $this->putLine ("$completeMail.\r\n");
  }

  /** Disconnect from the SMTP server
    */
  public function disconnect ()
  {
    if ($this->smtpStream === null)
      throw new \Exception (
                           _("Can't send email : not connected to SMTP server"),
                           500);
    $this->putLine ("QUIT\r\n");
    fclose ($this->smtpStream);
  }

  /** Reset the session to start a new mail in the same SMTP connection
    */
  public function reset ()
  {
    if ($this->smtpStream === null)
      throw new \Exception (
                           _("Can't send email : not connected to SMTP server"),
                           500);
    $this->putLine ("RSET\r\n");
  }

  /** Send something to the SMTP server. Wait the acknoledgement line
    */
  private function putLine ($data)
  {
    $this->debug ("> $data");
    fwrite ($this->smtpStream, $data);
    return $this->getLine ($data);
  }

  /** Wait something from the server
    */
  private function getLine ($message = "")
  {
    $this->debug ("Waiting for ".rtrim ($message)." answer\n", 2);
    $content = "";
    while (1)
    {
      $line = stream_get_line ($this->smtpStream, 1024, "\r\n");
      if ($line === false)
        break;
      $meta = stream_get_meta_data ($this->smtpStream);
      if ($meta["timed_out"] !== FALSE)
      {
        $this->debug ("Timeout when waiting $message\n");
        throw new  \Exception ("Timeout when waiting $message", 500);
      }
      $content .= $line."\r\n";
      if (substr ($line, 3, 1) === " ")
        break;
    }
    $this->debug ("< $content");
    if (substr ($line, 0, 1) !== "2" && substr ($line, 0, 1) !== "3")
    {
      $this->debug ("Can't send mail : server answer : $line\n");
      throw new \Exception ("Can't send mail : server answer : $line", 500);
    }
    return $content;
  }

  /** Save the connection debug in file
    */
  private function debug ($message, $priority = 1)
  {
    if ($this->debug == false)
      return;
    if ($priority > $this->debug)
      return;
    file_put_contents ($this->debugFile, $message, FILE_APPEND);
  }
}