<?php


function mailhandler_admin_retrieve($mid) {

  // Retrieve mailbox details for specified mailbox number
  $mailbox = mailhandler_get_mailbox($mid);

  // Check to see if there are new messages requiring retrieval
  $messages = mailhandler_get_unread_messages($mailbox);

  // If messages available, set batch and begin processing
  if ($messages) {
    foreach ($messages as $message_number) {
      $operations[] = array(
        'mailhandler_retrieve_message',
        array($mailbox, $message_number),
      );
    }

    // Create an array of batch operations
    $batch = array(
      'title' => 'Mailhandler retrieve',
      'operations' => $operations,
      'finished' => 'mailhandler_batch_finished',
      'init_message' => format_plural(count($messages), 'Preparing to retrieve 1 message...', 'Preparing to retrieve @count messages...'),
      'progress_message' => t('Retrieving message @current of @total.'),
      'file' => drupal_get_path('module', 'mailhandler') .'/mailhandler.retrieve.inc',
    );

    // Set the batch
    batch_set($batch);

    // Begin batch processing
    batch_process('admin/content/mailhandler');
  }
  else {
    // If there are no new messages, set a message
    drupal_set_message(t('There are no messages to retrieve for %mail.', array('%mail' => $mailbox['mail'])));
  }

  // Redirect to mailhandler overview form upon completion
  drupal_goto('admin/content/mailhandler');

}


/**
 * Returns the first part with the specified mime_type
 *
 * USAGE EXAMPLES - from php manual: imap_fetch_structure() comments
 * $data = get_part($stream, $msg_number, "TEXT/PLAIN"); // get plain text
 * $data = get_part($stream, $msg_number, "TEXT/HTML"); // get HTML text
 */
function mailhandler_get_part($stream, $msg_number, $mime_type, $structure = false, $part_number = false) {

  if (!$structure) {
    $structure = imap_fetchstructure($stream, $msg_number);
  }
  if ($structure) {
    foreach ($structure->parameters as $parameter) {
      if (strtoupper($parameter->attribute) == 'CHARSET') {
        $encoding = $parameter->value;
        //watchdog('mailhandler', 'Encoding is ' . $encoding);
      }
    }
    if ($mime_type == mailhandler_get_mime_type($structure)) {
      if (!$part_number) {
        $part_number = '1';
      }
      $text = imap_fetchbody($stream, $msg_number, $part_number);
      if ($structure->encoding == ENCBASE64) {
        return drupal_convert_to_utf8(imap_base64($text), $encoding);
      }
      else if ($structure->encoding == ENCQUOTEDPRINTABLE) {
        return drupal_convert_to_utf8(quoted_printable_decode($text), $encoding);
      }
      else {
        return drupal_convert_to_utf8($text, $encoding);
      }
    }
    if ($structure->type == TYPEMULTIPART) { /* multipart */
      while (list($index, $sub_structure) = each ($structure->parts)) {
        if ($part_number) {
          $prefix = $part_number .'.';
        }
        $data = mailhandler_get_part($stream, $msg_number, $mime_type, $sub_structure, $prefix . ($index + 1));
        if ($data) {
          return $data;
        }
      }
    }
  }

  return false;
}


/**
 * Returns an array of parts as file objects
 *
 * @param
 * @param $structure
 *   A message structure, usually used to recurse into specific parts
 * @param $max_depth
 *   Maximum Depth to recurse into parts.
 * @param $depth
 *   The current recursion depth.
 * @param $part_number
 *   A message part number to track position in a message during recursion.
 * @return
 *   An array of file objects.
 */
function mailhandler_get_parts($stream, $msg_number, $max_depth = 10, $depth = 0, $structure = FALSE, $part_number = FALSE) {
  $parts = array();

  // Load Structure.
  if (!$structure && !$structure = imap_fetchstructure($stream, $msg_number)) {
    watchdog('mailhandler', 'Could not fetch structure for message number %msg_number', array('%msg_number' => $msg_number), WATCHDOG_NOTICE);
    return $parts;
  }

  // Recurse into multipart messages.
  if ($structure->type == TYPEMULTIPART) {
    // Restrict recursion depth.
    if ($depth >= $max_depth) {
      watchdog('mailhandler', 'Maximum recursion depths met in mailhander_get_structure_part for message number %msg_number.',  array('%msg_number' => $msg_number), WATCHDOG_NOTICE);
      return $parts;
    }
    foreach($structure->parts as $index => $sub_structure) {
      // If a part number was passed in and we are a multitype message, prefix the
      // the part number for the recursive call to match the imap4 dot seperated part indexing.
      if ($part_number) {
        $prefix = $part_number .'.';
      }
      $sub_parts =  mailhandler_get_parts($stream, $msg_number, $max_depth, $depth + 1,
        $sub_structure, $prefix . ($index + 1));
      $parts = array_merge($parts, $sub_parts);
    }
    return $parts;
  }

  // Per Part Parsing.

  // Initalize file object like part structure.
  $part = new StdClass();
  $part->attributes = array();
  $part->filename = 'unnamed_attachment';
  if (!$part->filemime = mailhandler_get_mime_type($structure)) {
    watchdog('mailhandler', 'Could not fetch mime type for message part. Defaulting to application/octet-stream.', array(), WATCHDOG_NOTICE);
    $part->filemime = 'application/octet-stream';
  }

  if ($structure->ifparameters) {
    foreach ($structure->parameters as $parameter) {
      switch (strtoupper($parameter->attribute)) {
        case 'NAME':
        case 'FILENAME':
          $part->filename = $parameter->value;
          break;
        default:
          // put every thing else in the attributes array;
          $part->attributes[$parameter->attribute] = $parameter->value;
      }
    }
  }

  // Handle Content-Disposition parameters for non-text types.
  if ($structure->type != TYPETEXT && $structure->ifdparameters) {
    foreach ($structure->dparameters as $parameter) {
      switch (strtoupper($parameter->attribute)) {
        case 'NAME':
        case 'FILENAME':
          $part->filename = $parameter->value;
          break;
        // put every thing else in the attributes array;
        default:
          $part->attributes[$parameter->attribute] = $parameter->value;
      }
    }
  }

  // Retrieve part and convert MIME encoding to UTF-8
  if(!$part->data = imap_fetchbody($stream, $msg_number, $part_number)) {
    drupal_set_message("imap_fetchbody($stream, $msg_number, $part_number)");
    watchdog('mailhandler', 'No Data!!', array(), WATCHDOG_ERROR);
    return $parts;
  }

  // convert text attachment to UTF-8.
  if ($structure->type == TYPETEXT) {
    $part->data = imap_utf8($part->data);
  }
  else {
    // If not text then decode as necessary
    if ($structure->encoding == ENCBASE64) {
      $part->data = imap_base64($part->data);
    }
    else if ($structure->encoding == ENCQUOTEDPRINTABLE) {
      $part->data = quoted_printable_decode($part->data);
    }
  }

  //always return an array to satisfy array_merge in recursion catch, and array return value.
  $parts[] = $part;
  return $parts;
}


/**
 * Retrieve MIME type of the message structure.
 */
function mailhandler_get_mime_type(&$structure) {
  static $primary_mime_type = array('TEXT', 'MULTIPART', 'MESSAGE', 'APPLICATION', 'AUDIO', 'IMAGE', 'VIDEO', 'OTHER');
  $type_id = (int)$structure->type;
  if (isset($primary_mime_type[$type_id]) && !empty($structure->subtype)) {
    return $primary_mime_type[$type_id] .'/'. $structure->subtype;
  }
  return 'TEXT/PLAIN';
}


/**
 * Append default commands. Separate commands from body. Strip signature.
 * Return a node object.
 */
function mailhandler_process_message($header, $body, $mailbox) {

  // Initialise a node object
  $node = new stdClass();

  // Initialize parameters
  $sep = $mailbox['sigseparator'];

  // Copy any name/value pairs from In-Reply-To or References e-mail headers to $node. Useful for maintaining threading info.
  if ($header->references) {
    // we want the final element in references header, watching out for white space
    $threading = substr(strrchr($header->references, '<'), 0);
  }
  else if ($header->in_reply_to) {
    $threading = str_replace(strstr($header->in_reply_to, '>'), '>', $header->in_reply_to); // Some MUAs send more info in that header.
  }
  if ($threading = rtrim(ltrim($threading, '<'), '>')) { //strip angle brackets
    if ($threading) $node->threading = $threading;
    parse_str($threading, $tmp);
    if ($tmp['host']) {
      $tmp['host'] = ltrim($tmp['host'], '@'); // strip unnecessary @ from 'host' element
    }
    foreach ($tmp as $key => $value) {
      $node->$key = $value;
    }
  }

  // Prepend the default commands for this mailbox
  if ($mailbox['commands']) {
    $body = trim($mailbox['commands']) ."\n". $body;
  }

  // Process the commands and the body
  $lines = explode("\n", $body);
  for ($i = 0; $i < count($lines); $i++) {
    $line = trim($lines[$i]);
    $words = explode(' ', $line);

    // Look for a command line. if not present, note which line number is the boundary
    if (substr($words[0], -1) == ':' && is_null($endcommands)) {

      // Looks like a name: value pair
      $data = explode(': ', $line, 2);

      // TODO: allow for nested arrays in commands ... Possibly trim() values after explode().
      // If needed, turn this command value into an array
      if (substr($data[1], 0, 1) == '[' && substr($data[1], -1, 1) == ']') {
        $data[1] = rtrim(ltrim($data[1], '['), ']'); //strip brackets
        $data[1] = explode(",", $data[1]);
      }
      $data[0] = strtolower(str_replace(' ', '_', $data[0]));
      // if needed, map term names into IDs. this should move to taxonomy_mailhandler()
      if ($data[0] == 'taxonomy' && !is_numeric($data[1][0])) {
        array_walk($data[1], 'mailhandler_term_map');
      }
      $node->$data[0] = $data[1];
    }
    else {
      if (is_null($endcommands)) $endcommands = $i;
    }

    // Stop when we encounter the sig. we'll discard all remaining text.
    $start = substr($line, 0, strlen($sep)+3);
    if ($sep && strstr($start, $sep)) { // mail clients sometimes prefix replies with ' >'
      break;
    }
  }

  // Isolate the body from the commands and the sig
  $tmp = array_slice($lines, $endcommands, $i - $endcommands);
  // flatten and assign the body to node object. note that filter() is called within node_save() [tested with blog post]
  $node->body = implode("\n", $tmp);

  if (!$node->teaser) $node->teaser = node_teaser($node->body);

  // Set a default type if none provided
  if (!$node->type) $node->type = mailhandler_default_type();
  // decode encoded subject line
  $subjectarr = imap_mime_header_decode($header->subject);
  for ($i = 0; $i < count($subjectarr); $i++) {
    if ($subjectarr[$i]->charset != 'default')
      $node->title .= drupal_convert_to_utf8($subjectarr[$i]->text, $subjectarr[$i]->charset);
    else
      $node->title .= $subjectarr[$i]->text;
  }

  $node->created = $header->udate;
  $node->changed = $header->udate;
  $node->format = $mailbox['format'];

  return $node;
}


/**
 * Determine who is the author of the upcoming node.
 */
function mailhandler_authenticate($node, $header, $origbody, $mailbox) {

  // $fromaddress really refers to the mail header which is authoritative for authentication
  list($fromaddress, $fromname) = mailhandler_get_fromaddress($header, $mailbox);
  if ($from_user = mailhandler_user_load($fromaddress, $node->pass, $mailbox)) {
    $node->uid = $from_user->uid; // success!
    $node->name = $from_user->name;
  }
  else if (function_exists('mailalias_user')) { // since $fromaddress failed, try e-mail aliases
    $result = db_query("SELECT mail FROM {users} WHERE data LIKE '%%". $fromaddress ."%%'");
    while ($alias = db_result($result)) {
      if ($from_user = mailhandler_user_load($alias, $node->pass, $mailbox)) {
        $node->uid = $from_user->uid; // success!
        $node->name = $from_user->name;
        break;
      }
    }
  }
  if (!$from_user) {
    // failed authentication. we will still try to submit anonymously.
    $node->uid = 0;
    $node->name = $fromname; // use the name supplied in email headers
  }
  return $node;
}


/**
 * Create the comment.
 */
function mailhandler_comment_submit($node, $header, $mailbox, $origbody) {
  if (!$node->subject) $node->subject = $node->title;
  if (!$node->comment) $node->comment = $node->body;
  // We want the comment to have the email time, not the current time
  $node->timestamp = $node->created;
  // comment_save gets an array
  $edit = (array)$node;

  // post the comment. if unable, send a failure email when so configured
  if (!comment_save($edit) && $mailbox['replies']) {
    // $fromaddress really refers to the mail header which is authoritative for authentication
    list($fromaddress, $fromname) = mailhandler_get_fromaddress($header, $mailbox);
    $error_txt = t("Sorry, your comment experienced an error and was not posted. Possible reasons are\n- you have insufficient permission to post comments\n- The node is no longer open for comments.\n\n");
    $error = $error_txt. t("\n\nYou sent:\n\nFrom: %f\nSubject: %t\nBody:\n%b", array('%f' => $fromaddress, '%t' => $header->subject, '%b' => $origbody));
    $sitemail = variable_get('site_mail', ini_get('sendmail_from'));
    $headers = "From: $sitemail\nReply-to: $sitemail\nX-Mailer: Drupal\nReturn-path: $sitemail\nErrors-to: $sitemail";
    drupal_mail($fromaddress, t('Email submission to %sn failed - %subj', array('%sn' => variable_get('site_name', 'Drupal'), '%subj' => $header->subject)), $error, $headers);
    watchdog('mailhandler', 'Comment submission failure: %subject.', array('%subject' => $edit['subject']), WATCHDOG_ERROR);
  }
}


/**
 * Create the node.
 */
  // handle defaults for node creation (e.g. comment | promote | moderate | sticky fields)
  $node_blog_default = variable_get('node_options_blog', array('status', 'promote'));
  $node->status = in_array('status', $node_blog_default);
  $node->promote = in_array('promote', $node_blog_default);
  $node->moderate = in_array('moderate', $node_blog_default);
  $node->revision = in_array('revision', $node_blog_default);
  $node->comment = variable_get('comment_blog', 2);
function mailhandler_node_submit($node, $header, $mailbox, $origbody) {

  list($fromaddress, $fromname) = mailhandler_get_fromaddress($header, $mailbox);

  //dprint_r($node); //DEBUG

  node_validate($node);
  $error = form_get_errors();
  if (!$error) {
    // Prepare the node for save and allow modules make changes
    $node = node_submit($node);
    // Save the node
    if ($node->nid) {
      if (node_access('update', $node)) {
        node_save($node);
        watchdog('mailhandler', "Updated '%t' by %f", array('%t' => $node->title, '%f' => $fromaddress), WATCHDOG_INFO);
      }
      else {
        $errortxt = t("The e-mail address '%f' may not update %t items.", array('%f' => $fromaddress, '%t' => $node->type));
      }
    }
    else {
      if (node_access('create', $node)) {
        node_save($node);
        watchdog('mailhandler', "Added '%t' by %f", array('%t' => $node->title, '%f' => $fromaddress), WATCHDOG_INFO);
      }
      else {
        $errortxt = t("The e-mail address '%f' may not create %t items.", array('%f' => $fromaddress, '%t' => $node->type));
      }
    }
  }
  else {
    $errortxt = t("Your submission is invalid: \n\n");
    foreach ($error as $key => $value) {
      $errortxt .= "$key: $value\n";
    }
  }

  if ($errortxt) {
    watchdog('mailhandler', "$errortxt", array(), WATCHDOG_WARNING);
    if ($mailbox['replies']) {
      $errortxt .= t("\n\nYou sent:\n\nFrom: %f\nSubject: %t\nBody:\n%b", array('%f' => $fromaddress, '%t' => $header->subject, '%b' => $origbody));
      $sitemail = variable_get('site_mail', ini_get('sendmail_from'));
      $headers = "From: $sitemail\nReply-to: $sitemail\nX-Mailer: Drupal\nReturn-path: $sitemail\nErrors-to: $sitemail";
      drupal_mail($fromaddress, t('Email submission to %sn failed - %subj', array('%sn' => variable_get('site_name', 'Drupal'), '%subj' => $node->title)), $errortxt, $headers);
    }
  }
}


/**
 * Accept a taxonomy term name and replace with a tid. this belongs in taxonomy.module.
 */
function mailhandler_term_map(&$term) {
  // provide case insensitive and trimmed map so as to maximize likelihood of successful mapping
  $term = db_result(db_query("SELECT tid FROM {term_data} WHERE LOWER('". trim($term) ."') LIKE LOWER(name)"));
}


/**
 * Retrieve user information from his email address.
 */
function mailhandler_user_load($mail, $pass, $mailbox) {
  if ($mailbox['security'] == 1) {
    return user_load(array('mail' => $mail, 'pass' => $pass));
  }
  else {
    return user_load(array('mail' => $mail));
  }
}


/**
 * If available, use the mail header specified in mailbox config. otherwise use From: header
 */
function mailhandler_get_fromaddress($header, $mailbox) {
  if ($fromheader = strtolower($mailbox['fromheader']) && isset($header->$fromheader)) {
    $from = $header->$fromheader;
  }
  else {
    $from = $header->from;
  }
  return array($from[0]->mailbox .'@'. $from[0]->host, $from[0]->personal);
}


/**
 * Switch from original user to mail submision user and back.
 *
 * Note: You first need to run mailhandler_switch_user without
 * argument to store the current user. Call mailhandler_switch_user
 * without argument to set the user back to the original user.
 *
 * @param $uid The user ID to switch to
 *
 */
function mailhandler_switch_user($uid = NULL) {
  global $user;
  static $orig_user = array();

  if (isset($uid)) {
    $user = user_load(array('uid' => $uid));
  }
  // retrieve the initial user, can be called multiple times
  else if (count($orig_user)) {
    $user = array_shift($orig_user);
    array_unshift($orig_user, $user);
  }
  // store the initial user
  else {
    $orig_user[] = $user;
  }
}


function mailhandler_batch_finished($success, $results, $operations) {
  if ($success) {
    $message = format_plural(count($results), '1 message retrieved for %mailbox.', '@count messages retrieved for %mailbox.', array('%mailbox' => $results[0]));
    drupal_set_message($message);
  }
}


function mailhandler_get_unread_messages($mailbox) {

  $unread_messages = array();
  $result = mailhandler_open_mailbox($mailbox);

  if ($result) {

    $number_of_messages = imap_num_msg($result);
    for ($i = 1; $i <= $number_of_messages; $i++) {
      $header = imap_header($result, $i);

      // only process new messages
      if (!$mailbox['delete_after_read'] && $header->Unseen != 'U' && $header->Recent != 'N') {
        continue;
      }

      $unread_messages[] = $i;
    }
  }

  imap_close($result);
  return $unread_messages;
}


function mailhandler_retrieve_message($mailbox, $i, &$context) {

  mailhandler_switch_user();

  $result = mailhandler_open_mailbox($mailbox);

  if ($result) {

      $header = imap_header($result, $i);

      $mime = explode(',', variable_get('mime', 'TEXT/HTML,TEXT/PLAIN'));

      // Get the first text part - this will be the node body
      $origbody = mailhandler_get_part($result, $i, $mime[0]);

      // If we didn't get a body from our first attempt, try the alternate format (HTML or PLAIN)
      if (!$origbody) {
        $origbody = mailhandler_get_part($result, $i, $mime[1]);
      }

      // Parse MIME parts, so all mailhandler modules have access to
      // the full array of mime parts without having to process the email.
      $mimeparts = mailhandler_get_parts($result, $i);

      // Is this an empty message with no body and no mimeparts?
      if (!$origbody && !$mimeparts) {
        // @TODO: Log that we got an empty email?
        imap_close($result);
        return;
      }

      // we must process before authenticating because the password may be in Commands
      $node = mailhandler_process_message($header, $origbody, $mailbox);

      // check if mail originates from an authenticated user
      $node = mailhandler_authenticate($node, $header, $origbody, $mailbox);

      // Put $mimeparts on the node
      $node->mimeparts = $mimeparts;

      // we need to change the current user
      // this has to be done here to allow modules
      // to create users
      mailhandler_switch_user($node->uid);

      // modules may override node elements before submitting. they do so by returning the node.
      foreach (module_list() as $name) {
        if (module_hook($name, 'mailhandler')) {
          $function = $name .'_mailhandler';
          if (!($node = $function($node, $result, $i, $header, $mailbox))) {
            // Exit if a module has handled the submitted data.
            break;
          }
        }
      }

      if ($node) {
        if ($node->type == 'comment') {
          mailhandler_comment_submit($node, $header, $mailbox, $origbody);
        }
        else {
          mailhandler_node_submit($node, $header, $mailbox, $origbody);
        }
      }
      // don't delete while we're only getting new messages
      if ($mailbox['delete_after_read']) {
        imap_delete($result, $i);
      }

      // switch back to original user
      mailhandler_switch_user();

      // Put something in the results array for the counter in the batch finished callback
      $context['results'][] = $mailbox['mail'];
    }

    imap_close($result, CL_EXPUNGE);

    mailhandler_switch_user();

}


/**
 * Retrieve messages when triggered by cron
 *
 * To prevent timeouts when handling large messages we can limit the number of messages processed on each
 * cron run, using a setting on the configuration page. A setting of zero means no limit is applied.
 *
 * Flagging messages as unseen only works for IMAP so for POP mail to use limited downloads messages must
 * be deleted after retrieval to prevent repeated downloading of the same messages on each run
 */
function mailhandler_cron_retrieve($mailbox) {

  // Find out how many messages need retrieval
  $new_messages = mailhandler_get_unread_messages($mailbox);

  // Initialise counters for maximum message retrieval
  $max_messages = variable_get('mailhandler_max_retrieval', 0);
  $retrieved_messages = 0;

  // Begin retrieval of messages
  while ($new_messages && (!$max_messages || $retrieved_messages < $max_messages)) {
    mailhandler_retrieve_message($mailbox, array_shift($new_messages), &$context);
    $retrieved_messages++;
  }

}