<?php
// $Id$

/**
 * @file
 * Allows users to send private messages to other users.
 */

define('THREADED', 0);

function privatemsg_init() {
  require_once(drupal_get_path('module', 'privatemsg') .'/privatemsgapi/privatemsgapi.inc');
}

/**
 * Implementation of hook_perm().
 */
function privatemsg_perm() {
  return array(
    'read privatemsg',
    'read all private messages',
    'administer privatemsg settings',
    'create new folder',
    'write privatemsg'
  );
}

/**
 * Implementation of hook_menu().
 */
function privatemsg_menu() {
  $items['messages'] = array(
    'title'            => 'Private messages',
    'page callback'    => 'privatemsg_list',
    'access arguments' => array('read privatemsg'),
    'type'             => MENU_NORMAL_ITEM,
  );
  $items['messages/inbox'] = array(
    'title'            => 'Inbox',
    'page callback'    => 'privatemsg_list',
    'access arguments' => array('read privatemsg'),
    'type'             => MENU_DEFAULT_LOCAL_TASK,
    'weight'           => -10,
  );
  $items['messages/mark-read'] = array(
    'title' => 'Mark all as read',
    'page callback'    => 'privatemsg_set_new_status',
    'page arguments'   => array(NULL, NULL, 0, TRUE),
    'access callback'  => 'privatemsg_unread_count',
    'type'             => MENU_NORMAL_ITEM,
    'weight'           => -9,
  );
  $items['messages/sent'] = array(
    'title'            => 'Sent messages',
    'page callback'    => 'privatemsg_list',
    'access arguments' => array('read privatemsg'),
    'type'             => MENU_LOCAL_TASK,
    'weight'           => -5,
  );
  $items['messages/view/%'] = array(
    'title'            => 'Read private message',
    'page callback'    => 'privatemsg_view',
    'page arguments'   => array(2),
    'access arguments' => array('read privatemsg'),
    'type'             => MENU_CALLBACK,
    'weight'           => -10,
  );
  $items['messages/new'] = array(
    'title' => 'Create',
    'page callback'    => 'drupal_get_form',
    'page arguments'   => array('privatemsg_new'),
    'access arguments' => array('write privatemsg'),
    'type'             => MENU_LOCAL_TASK,
    'weight'           => -7,
  );
  $items['messages/new/%message_recipient'] = array(
    'page callback'    => 'drupal_get_form',
    'page arguments'   => array('privatemsg_new', 2),
    'access arguments' => array('write privatemsg'),
    'type'             => MENU_CALLBACK,
    'weight'           => -10,
  );
  // Auto-completes available user names & removes duplicates.
  $items['messages/user-name-autocomplete'] = array(
    'page callback'    => 'privatemsg_user_name_autocomplete',
    'access arguments' => array('write privatemsg'),
    'type'             => MENU_CALLBACK,
    'weight'           => -10,
  );
  $items['admin/settings/messages'] = array(
    'title'            => 'Private messages',
    'description'      => 'Configure private messaging settings.',
    'page callback'    => 'drupal_get_form',
    'page arguments'   => array('private_message_settings'),
    'access arguments' => array('administer privatemsg settings'),
    'type'             => MENU_NORMAL_ITEM,
  );
  return $items;
}

function message_recipient_load($uid) {
  $user = NULL;
  if (is_numeric($uid)) {
    $user = user_load(array('uid' => $uid));
  }
  return $user;
}

function private_message_view_options() {
  $options = module_invoke_all('privatemsg_view_template');
  return $options;
}

/**
 * Implementation of hook_privatemsg_view_template().
 *
 * Allows modules to define different message view template.
 *
 * This hook returns information about available themes for privatemsg viewing.
 *
 * array(
 *  'machine_template_name' => 'Human readable template name',
 *  'machine_template_name_2' => 'Human readable template name 2'
 * };
 */
function privatemsg_privatemsg_view_template() {
  return array(
    'privatemsg-view' => 'Default view',
  );
}

function private_message_settings() {
  $form = array();

  $form['theming_settings'] = array(
    '#type'        => 'fieldset',
    '#collapsible' => TRUE,
    '#collapsed'   => TRUE,
    '#title'       => t('Theming settings'),
  );
  $form['theming_settings']['private_message_view_template'] = array(
    '#type'          => 'radios',
    '#title'         => t('Private message display template'),
    '#default_value' => variable_get('private_message_view_template', 'privatemsg-view'),
    '#options'       => private_message_view_options(),
  );
  $form['#submit'][] = 'private_message_settings_submit';
  return system_settings_form($form);
}

function private_message_settings_submit() {
  drupal_rebuild_theme_registry();
}

function privatemsg_theme() {
  return array(
    'privatemsg_view'    => array(
      'arguments'        => array('message' => NULL),
      'template'         => variable_get('private_message_view_template', 'privatemsg-view'),//'privatemsg',
    ),
    'privatemsg_from'    => array(
      'arguments'        => array('author' => NULL),
      'template'         => 'privatemsg-from',
    ),
    'privatemsg_to'      => array(
      'arguments'        => array('message' => NULL),
      'template'         => 'privatemsg-recipients',
    ),
    'privatemsg_between' => array(
      'arguments'        => array('recipients' => NULL),
      'template'         => 'privatemsg-between',
    ),
  );
}

function privatemsg_preprocess_privatemsg_view(&$vars) {
  $message = $vars['message'];
  $vars['author_picture'] = theme('user_picture', $message['author']);
  $vars['author_name_link'] = theme('username', $message['author']);
  $vars['message_timestamp'] = date("M j \a\\t g:ia", $message['timestamp']);
  $vars['message_body'] = check_markup($message['body']);
//  drupal_set_message('<pre>'. print_r('what', 1) .'</pre>');
//  drupal_set_message('<pre>'. print_r(func_get_args(), 1) .'</pre>');
//  drupal_set_message('<pre>'. print_r($vars, 1) .'</pre>');
}

function privatemsg_preprocess_privatemsg_to(&$vars) {
  global $user;
  $to = array();
  if (isset($vars['message']['participants'])) {
    foreach ($vars['message']['participants'] as $uid => $account) {
      if ($account->uid == $user->uid) {
        $last = theme('username', $account);
      }
      else{
        $to[]= theme('username', $account);
      }
    }
  }
  if (!($last) && count($to) > 0) {
    $last = array_pop($to);
  }

  $participants = implode(', ', $to);
  if (drupal_strlen($participants)) {
    $participants .= " and ";
  }

  $vars['participants'] = 'Between '. $participants . $last;
}

/**
 * List messages.
 *
 * @param $uid - user id for whom to load messages.
 */
function privatemsg_list($uid = NULL) {
  global $user;
  disallow_anon_access();

  if (!$uid) {
    // Default behavior: we are trying to view our own private messages if no uid is passed...
    $account = $user;
  }
  else { // ...or we are viewing either our own or someone else's messages.
    if ($uid && $uid == $user->uid) { // Viewing our own messages.
      $account = $user;
    }
    else if ($uid && $uid != $user->uid && user_access('read all private messages')) {
      $account = user_load(array('uid' => $uid));
    }
    else { // We tried viewing someone else's messages but didn't have sufficient rights.
      drupal_set_message("You do not have sufficient rights to view someone else's messages", WATCHDOG_WARNING);
      $account = $user;
    }
  }
  // By this point we have figured out for which user we are listing messages and now it is safe to use $account->uid in the listing query.

//  drupal_set_message('<pre>'. print_r($uid, 1) .'</pre>');
  switch (arg(1)) {
    case 'sent':
      $query = _privatemsg_assemble_query('privatemsg_list_sent', $account);
      break;
    case 'inbox':
    default:
      $query = _privatemsg_assemble_query('privatemsg_list', $account);
  }
  $result = db_query($query);

//  drupal_set_message('<pre>'. print_r($query, 1) .'</pre>');

  $messages = array();
  while ($row = db_fetch_array($result)) {
    $row['subject'] = l($row['subject'], 'messages/view/'. $row['id']);
    $messages[] = $row;
  }

  $head = array();
  if (count($messages)) {
    $row = $messages[0];
    foreach ($row as $index => $value) {
      switch ($index) {
        case 'id':
          continue 2;
        case 'author':
      	  $col = 'from';
      	  break;
        case 'recipient':
          $col = 'to';
          break;
        case 'timestamp':
          $col = arg(1) == 'sent' ? 'sent' : 'received';
          break;
        default:
          $col = $index;
      }
      $head[$index] =  array('data' => t($col), 'field' => $index, 'sort'=> 'desc');
    }
    if (arg(1) == 'inbox') {
      $query = _privatemsg_assemble_query('privatemsg_list', $account);
    }
    else if (arg(1) == 'sent') {
      $query = _privatemsg_assemble_query('privatemsg_list_sent', $account);
    }

    $result = db_query($query);
    if (arg(1) != 'sent') {
      unset($head['new']);
    }
    unset($head['thread_id']);

    $messages = array();
    while ($row = db_fetch_array($result)) {
      $unread = '';
      if (isset($row['new']) && $row['new'] ) {
        $unread = ' privatemsg-unread';
      }
      $row['subject'] = '<span class="privatemsg-list-subject'. $unread.'">' . l($row['subject'], 'messages/view/'. $row['thread_id']) . '</span>';
      if (isset($row['author']) && $row['author']) {
        $row['author'] = '<span class="privatemsg-list-from' .  $unread.'">' . theme('username', user_load($row['author'])) . '</span>';
      }
      if (isset($row['recipient']) && $row['recipient']) {
        $row['recipient'] = '<span class="privatemsg-list-to' .  $unread.'">' . theme('username', user_load($row['recipient'])) . '</span>';
      }
      if ($row['timestamp']) {
        $row['timestamp'] = '<span class="privatemsg-list-date' .  $unread.'">' . format_date($row['timestamp'],'small') . '</span>';
      }
      if (arg(1) != 'sent') {
        unset($row['new']);
      }
      unset($row['id']);
      unset($row['thread_id']);
      $messages[] = $row;
    }
    $content = theme('table', $head, $messages);
    drupal_add_css(drupal_get_path('module', 'privatemsg').'/styles/privatemsg-list.css');
  }
  else {
    $content = '';
    drupal_set_message('No messages to display.');
  }

//  drupal_set_message('<pre>'. print_r(count($messages), 1) .'</pre>');

  // Begin theming process.
  // 1) Expose each message to table header and table row alteration.
  // 2) Something else.
  return $content;
}

/**
 * API function
 *
 * Sets a single message as read for a user.
 */
function privatemsg_mark_as_read($pmid, $account) {
  $query = "UPDATE {pm_index} SET new = 0 WHERE mid = %d AND recipient = %d";
  db_query($query, $pmid, $account->uid);
}

/**
 * API function
 *
 * Return number of unread messages for an account.
 */
function privatemsg_unread_count($account = NULL) {
  if (!$account || $account->uid == 0) {
    global $user;
    $account = $user;
  }
  $query = _privatemsg_assemble_query('privatemsg_unread_count', $account);
  return db_result(db_query($query));
}

/**
 * API function
 *
 * Change status of one or ALL messages to read / unread.
 */
function privatemsg_set_new_status($account = NULL, $mid = NULL, $new = 0, $verbose = FALSE) {
  if (!$account || 0 == $account->uid) {
    global $user;
    $account = $user;
  }
  $query = "UPDATE {pm_index} pmi SET new = %d WHERE recipient = %d AND new = %d";
  $arg[] = $new;
  $arg[] = $account->uid;
  $arg[] = ($new == 0) ? 1 : 0;
  if ($mid) {
    $query .= " AND mid = %d";
    $arg[] = $mid;
  }

  $result = db_query($query, $arg) ;

  if ($verbose) {
    if ($result) {
      if ($new == 1) {
        $status = 'Unread';
      }
      else {
        $status = 'Read';
      }
      $total_marked = db_affected_rows();
      $msg =  format_plural($total_marked, "1 message marked as <em>!status</em>", '@count messages marked as <em>!status</em>', array('!status' => $status));
      drupal_set_message($msg);
    }
    else {
      drupal_set_message('An error has occured, please contact the site administrator.', 'error');
    }
    return '';
  }
}

function privatemsg_view($thread_id) {
  global $user;
  $output = '';
  // Load the message object.
  $query = _privatemsg_assemble_query('privatemsg_messages', $thread_id, $user->uid);
  $conversation = db_query($query);
  $message_count = 0;
  while ($result = db_fetch_array($conversation)) {
    $pmid = $result['mid'];
    $message = _privatemsg_load($pmid, $user->uid);
    privatemsg_set_new_status($user, $pmid);
    $message['author'] = user_load($message['author']);
    // Some tasks only need to be done once - on the first message of a thread.
    if ($message_count == 0) {
      $subject = $message['subject'];
      drupal_set_title($subject);
      // Load the list of participants.
      $query = _privatemsg_assemble_query('privatemsg_participants', $thread_id);
      $participants = db_query($query);
      while ($result = db_fetch_object($participants)) {
        $message['participants'][] = user_load($result->uid);
      }
      $output = theme('privatemsg_to', $message);
    }
    $output .= theme('privatemsg_view', $message);
    $message_count++;
  }

  if (user_access('write privatemsg')) {
    $output .= drupal_get_form('privatemsg_new');
  }
  return $output;
}

function privatemsg_new(&$form_state, $user = NULL) {
  $recipient = '';
  $subject   = '';
  $body      = '';

  if (isset($user)) {
    $recipient  = $user->name .', ';
  }
  if (isset($form_state['values'])) {
    $form_values = $form_state['values'];
    $recipient = $form_values['recipient'];
    $subject   = $form_values['subject'];
    $body      = $form_values['body'];
  }

  $form = array();
  if (isset($form_state['privatemsg_preview'])) {
    $form['message_header'] = array(
      '#type' => 'fieldset',
      '#attributes' => array('class' => 'preview'),
    );
    $form['message_header']['message_preview'] = array(
      '#value'  => $form_state['privatemsg_preview'],
    );
  }
  $form['header']               = array(
    '#type'               => 'fieldset'
  );
  $form['header']['recipient']  = array(
    '#type'               => 'textfield',
    '#title'              => t('To'),
    '#description'        => t('Separate multiple names with commas.'),
    '#default_value'      => $recipient,//populate this later
    '#size'               => 50,
    '#autocomplete_path'  => 'messages/user-name-autocomplete',
    // Do not hardcode #maxlength, make it configurable by number of recipients, not their name length.
  );
  $form['header']['subject']    = array(
    '#type'               => 'textfield',
    '#title'              => t('Subject'),
    '#size'               => 50,
    '#maxlength'          => 255,
    '#default_value'      => $subject,
  );
  $form['content'] = array(
    '#type'               => 'fieldset',
  );
  $form['content']['body']       = array(
    '#type'               => 'textarea',
    '#title'              => t('Message'),
    '#cols'               => 10,
    '#rows'               => 6,
    '#default_value'      => $body,
  );
  $form['controls'] = array(
    '#type'               => 'fieldset',
  );
  $form['controls']['preview'] = array(
    '#type'               => 'submit',
    '#value'              => 'Preview',
    '#submit'             => array('pm_preview'),
  );
  $form['controls']['submit'] = array(
    '#type'               => 'submit',
    '#value'              => 'Send',
    '#submit'             => array('pm_send'),
  );
  $form['controls']['cancel'] = array(
    '#type'               => 'submit',
    '#value'              => t('Cancel'),
    '#submit'             => array('pm_cancel'),
  );
  $form['#validate'][]    = 'pm_send_validate';

  return $form;
}

function pm_cancel($form, &$form_state) {
  $form_state['redirect'] = 'messages/new';
}

function pm_send_validate($form, &$form_state) {
  global $user;
  $form_values = $form_state['values'];
//  if ($form_state['clicked_button']['#value'] == t('Cancel')) {
//    return ;
//  }
  if (empty($form_values['recipient'])) {
    form_set_error('recipient', t("You must fill out the <em>!to</em> field.", array('!to' => $form['header']['recipient']['#title'])));
  }
  if (empty($form_values['subject'])) {
    form_set_error('subject', t("You must fill out the <em>!subject</em> field.", array('!subject' => $form['header']['subject']['#title'])));
  }
  if (empty($form_values['body'])) {
    form_set_error('body', t("You must fill out the <em>!body</em> field.", array('!body' => $form['content']['body']['#title'])));
  }
//  drupal_set_message('<pre>'. print_r($form, 1). '</pre>');
//  drupal_set_message('<pre>'. print_r($form_state, 1). '</pre>');
  // The actual message that is being sent, we create this during validation and pass to submit to send out.
  $message = array();
  $message['body']      = $form_values['body'];
  $message['subject']   = $form_values['subject'];
  $message['author']    = $user;
  $message['timestamp'] = time();
  if (isset($form_values['thread_id']) && $form_values['thread_id']) {
    $message['thread_id'] = $form_values['thread_id'];
  }

//  drupal_set_message('<pre>'. print_r('one', 1) .' </pre>');

//  drupal_set_message('<pre>'. print_r($form_state, 1) .' </pre>');

  // Verify that recipient's name syntax is correct.
  $fragments = explode(',', $form_values['recipient']);
  $invalid = array();
  $valid   = array();
  foreach ($fragments as $index => $name) {
    $name = trim($name);
    if (!empty($name)) { // We don't care about white space names.
      if (empty($name) || $error = module_invoke('user', 'validate_name', $name)) {
        // These names are invalid due to incorrect user name syntax.
        $invalid[$name] = $name;
      }
      else {
        $valid[$name] = $name;  // These are valid only due to user name syntax. We still need to check if the user exists and accepts messages.
      }
    }
  }

  // Verify users exist and load their accounts.
  foreach ($valid as $index => $name) {
    if ($account = user_load(array('name' => $name))) {
      // Helps avoid duplicates.
      $message['recipients'][$account->uid] = $account;
    }
    else {
      // Here we add more invalid names due to the fact that they don't exist.
      $invalid[$name] = $name;
    }
  }
  // When user sends a message he also sends a message to himself.
//  if ($user->uid) {
//    $message['recipients'][$user->uid] = $user;
//  }

  /**
   * @TODO: Add banned and blocked users check later.
   */

  // Verify that our recipients are valid.
  /**
   * VALIDATE NAMES
   * 1) Make sure the name exists.
   * 2) Make sure he accepts private messages.
   * 3) Make sure the sender is not on block list of the recipient.
   */
  /**
   * BUILD VALID RECIPIENT LIST
   * 1) Names that were not valid from previous step will be stripped out.
   * 2) Names that remain will be put into a recipients array.
   */

  $form_state['validate_built_message'] = $message;
  if (!empty($invalid)) {
    drupal_set_message('The following users will not receive this private message: '. check_plain(implode(", ", $invalid)), 'error');
  }
}

function pm_send($form, &$form_state) {
//  drupal_set_message('<pre>'. print_r('two', 1) .' </pre>');
//  drupal_set_message('<pre>'. print_r($form_state, 1) .' </pre>');;
  $message = $form_state['validate_built_message'];
//  drupal_set_message('<pre>'. print_r($message, 1) .' </pre>');;
  // 1) Save the message body first.
  $args = array();
  $args[] = $message['subject'];
  $args[] = $message['author']->uid;
  $args[] = $message['body'];
  $query = "INSERT INTO {pm_message} (mid, subject, author, body) VALUES (null, '%s', %d, '%s')";
  $resuld = db_query($query, $args);
  $mid = db_last_insert_id('pm_message', 'mid');
  $message['mid'] = $mid;

  // Thread ID is the same as the mid if it's the first message in the thread.
  if (!isset($message['thread_id'])) {
    $message['thread_id'] = $mid;
  }
  // 2) Save message to recipients.
  // Each recipient gets a record in the pm_index table.
  $query = "INSERT INTO {pm_index} (mid, thread_id, recipient, author, timestamp, new) VALUES (%d, %d, %d, %d, %d, 1)";
  foreach ($message['recipients'] as $recipient) {
    $mid = $message['mid'];
    $thread_id  = $message['thread_id'];
    $timestamp = $message['timestamp'];
    db_query($query, $mid, $thread_id, $recipient->uid, $message['author']->uid , $timestamp);
  }

  drupal_set_message('A private message has been sent to '. $form_state['values']['recipient']);
}

function privatemsg_render_preview($message) {
  global $user;
  $from = '';
  $to   = array();
  $subject = $message['subject'];
  $timestamp = $message['timestamp'];
  $body = $message['body'];
  if (isset($message['recipients'])) {
    foreach ($message['recipients'] as $uid => $account) {
      $to[]= theme('username', $account);
    }
  }
  if (empty($to)) {
    $to[] = theme('username', $user);
  }
  $to = implode(', ', $to);
  $from = theme('username', $user);
  return theme('privatemsg_view', $message);
}

function pm_preview($form, &$form_state) {
//  drupal_set_message('<pre>two </pre>');
//  drupal_set_message('<pre>'. print_r($form_state, 1) .' </pre>');

  $form_values = $form_state['values'];
  $op = isset($form_values['op']) ? $form_values['op'] : '';
  if ($op == t('Preview')) {
    drupal_validate_form($form['form_id']['#value'], $form, $form_state);
    if (!form_get_errors()) {
//  drupal_set_message('<pre>'. print_r($form, 1) .' </pre>');;
      //TODO: Generate message preview here.
      $form_state['privatemsg_preview'] = privatemsg_render_preview($form_state['validate_built_message']);
    }
  }
  $form_state['rebuild'] = TRUE; //this forces our form to be rebuilt instead of being submitted.
}

function privatemsg_privatemsg_list_sent_alter(&$fragments, $account) {
  $fragments['primary_table'] = '{pm_message} pm';

  $fragments['select'][]      = 'MAX(pm.mid) as id';
  $fragments['select'][]      = 'pmi.thread_id';
  $fragments['select'][]      = 'pm.subject';
  if ($account->uid != $GLOBALS['user']->uid) {
    $fragments['select'][] = 'pmi.author';
  }
  $fragments['select'][] = 'pmi.recipient';
  $fragments['select'][] = 'pmi.timestamp';
  $fragments['inner_join'][]  = 'INNER JOIN {pm_index} pmi ON pm.mid = pmi.mid';
  $fragments['where'][]       = 'pmi.author = %d';
  $fragments['group_by'][]  = 'pmi.thread_id';
  $order = 'MAX(pmi.timestamp)';
  $sort = 'desc';
  if (isset($_GET['order'])) {
    switch ($_GET['order']) {
      case ('subject'):
        $order = 'pm.subject';
        break;
      case ('from'):
        $order = 'pmi.author';
        break;
      case ('to'):
        $order = 'pmi.recipient';
        break;
      case ('sent'):
      default:
        $order = 'pmi.timestamp';
    }
    $sort = isset($_GET['sort']) && ($_GET['sort'] == 'asc' || $_GET['sort'] == 'desc') ? $_GET['sort'] : 'desc';
  }
  $fragments['order_by'][]  = $order . ' ' . $sort;
  $fragments['query_args'][]  = $account->uid;
}

function privatemsg_privatemsg_list_alter(&$fragments, $account) {
  $fragments['primary_table'] = '{pm_message} pm';

  $fragments['select'][]      = 'MAX(pmi.mid) as id';
  $fragments['select'][]      = 'pmi.thread_id';
  $fragments['select'][]      = 'pm.subject';
  $fragments['select'][]      = 'pmi.author';
  if ($account->uid != $GLOBALS['user']->uid) {
    $fragments['select'][] = 'pmi.recipient';
  }
  $fragments['select'][] = 'pmi.timestamp';
  $fragments['select'][] = 'MAX(pmi.new) as new';
  $fragments['inner_join'][]  = 'INNER JOIN {pm_index} pmi ON pm.mid = pmi.mid';
  $fragments['where'][]       = 'pmi.recipient = %d';
  $fragments['group_by'][]  = 'pmi.thread_id';
  $order = 'pmi.new';
  $sort = 'desc';
  if (isset($_GET['order'])) {
    switch ($_GET['order']) {
      case ('subject'):
        $order = 'pm.subject';
        break;
      case ('from'):
        $order = 'pmi.author';
        break;
      case ('to'):
        $order = 'pmi.recipient';
        break;
      case ('received'):
      default:
        $order = 'MAX(pmi.timestamp)';
    }
    $sort = isset($_GET['sort']) && ($_GET['sort'] == 'asc' || $_GET['sort'] == 'desc') ? $_GET['sort'] : 'desc';
  }
  $fragments['order_by'][]  = $order . ' ' . $sort . ', MAX(pmi.mid) DESC';
  $fragments['query_args'][]  = $account->uid;

}

function privatemsg_privatemsg_load_alter(&$fragments, $pmid, $uid) {
//  drupal_set_message('<pre>'. print_r(func_get_args(), 1) . '</pre>');
  $fragments['primary_table'] = '{pm_message} pm'; // Our primary table

  $fragments['select'][]      = "pm.*"; // Gets all data from primary table.
  $fragments['select'][]      = "pmi.*";

  $fragments['inner_join'][]  = 'INNER JOIN {pm_index} pmi ON pm.mid = pmi.mid';
  $fragments['where'][]       = 'pmi.mid = %d';
  $fragments['query_args'][]  = $pmid;
  $fragments['where'][]       = 'pmi.recipient = %d or pmi.author = %d';
  $fragments['query_args'][]  = $uid;
  $fragments['query_args'][]  = $uid;
}

function privatemsg_privatemsg_messages_alter(&$fragments, $thread_id, $uid) {
  $fragments['primary_table'] = '{pm_index} pmi';

  $fragments['select'][]      = 'DISTINCT(pmi.mid) as mid';
  $fragments['where'][]       = 'pmi.thread_id = %d';
  $fragments['query_args'][]  = $thread_id;
  if (!(user_access('read all private messages'))) {
    $fragments['where'][]       = 'pmi.author = %d';
    $fragments['query_args'][]  = $uid;
    $fragments['union_select'][]      = 'DISTINCT(pmi.mid) as mid';
    $fragments['union_where'][]       = 'pmi.thread_id = %d';
    $fragments['union_where'][]       = 'pmi.recipient = %d';
    $fragments['query_args'][]  = $thread_id;
    $fragments['query_args'][]  = $uid;
  }
  $fragments['order_by'][]  = 'mid ASC';
}

function privatemsg_privatemsg_participants_alter(&$fragments, $thread_id) {
  $fragments['primary_table'] = '{pm_index} pmi';

  $fragments['select'][]      = 'pmi.recipient as uid';
  $fragments['where'][]       = 'pmi.thread_id = %d';
  $fragments['union_select'][] = 'pmi.author as uid';
  $fragments['union_where'][] = 'pmi.thread_id = %d';
  $fragments['query_args'][]  = $thread_id;
  $fragments['query_args'][]  = $thread_id;
}


function privatemsg_privatemsg_unread_count_alter(&$fragments, $account) {
  $fragments['primary_table'] = '{pm_index} pmi';

  $fragments['select'][]      = 'count(*) as unread_count';
  $fragments['where'][]       = 'pmi.new = 1';
  $fragments['where'][]       = 'pmi.recipient = %d';
  $fragments['query_args'][]  = $account->uid;
}

/**
 * Return autocomplete results for usernames.
 * Prevents usernames from being used and/or suggested twice.
 */
function privatemsg_user_name_autocomplete($string) {
  $names = array();
  // 1: Parse $string and build list of valid user names.
  $fragments = explode(',', $string);
  foreach ($fragments as $index => $name) {
    $name = trim($name);
    if ($error = module_invoke('user', 'validate_name', $name)) {
      // Do nothing if this name does not validate.
    }
    else {
      $names[$name] = $name;
    }
  }

  // By using user_validate_user we can ensure that names included in $names are at least logisticaly possible.
  // 2: Find the next user name suggestion.
  $fragment = array_pop($names);
  if (!empty($fragment)) {
    $query = "SELECT name FROM {users} u WHERE name like '%s%%'";
    $query .= " AND name NOT IN ('". implode("', '", $names) ."')"; // This will prevent suggesting a name that is already in our list.
    $query .= " AND status <> 0 ORDER BY name ASC";
    $result = db_query_range($query, $fragment, 0, 10);
    $prefix = count($names) ? implode(", ", $names) .", " : '';
    // 3: Build proper suggestions and print.
    $matches = array();
    while ($user = db_fetch_object($result)) {
      $matches[$prefix . $user->name .", "] = $user->name;
    }
    print drupal_to_js($matches);
    exit();
  }
}

/**
 * Use this function at the top of your own function to block anon user access.
 */
function disallow_anon_access() {
  global $user;
  if (!$user->uid) {
    // Even though admin/user/permissions may allow anonymous users
    // to access privatemsg, it still doesn't make sense for that to
    // happen. Therefore, we disallow this here so there's no way to bypass it.
    drupal_access_denied();
    exit;
  }
}

function privatemsg_user($op, &$edit, &$account, $category = NULL) {
  global $user;


  switch ($op) {
    case 'view':
      if (user_access('write privatemsg') && $user->uid <> $account->uid) {
        $account->content['privatemsg_send_new_message'] = array(
          '#type'   => 'markup',
          '#value'  => l('Send this user a private message', 'messages/new/'. $account->uid, array('query' => 'destination='. $_GET['q'])),
          '#weight' => 10,
        );
      }
      break;
    case 'login':
      $count = privatemsg_unread_count();
      if ($count) {
        $login_msg = 'You have ';
        $login_msg .= $count > 1 ? l($count .' unread messages', 'messages/inbox') : l($count .' unread message', 'messages/inbox');
        $login_msg .= '.';
        drupal_set_message($login_msg);
      }
      break;
  }
}

function privatemsg_block($op = 'list', $delta = 0, $edit = array()) {
  if ('list' == $op) {
    $blocks = array();
    $blocks['privatemsg-menu'] = array(
      'info' => t('Privatemsg links'),
    );

    return $blocks;
  }
  else if ('view' == $op) {
    $block = array();
    switch ($delta) {
      case 'privatemsg-menu':
        $block = _privatemsg_block_menu();
        break;
    }
    return $block;
  }
}

function _privatemsg_block_menu() {
  $block = array();

  $count = privatemsg_unread_count();
  $new = '';
  if ($count) {
    $new = " ({$count})";
  }
  $links = array();
  if (user_access('write privatemsg')) {
    $links[] = l('Create private message', 'messages/new');
  }
  if (user_access('read privatemsg') || user_access('read all private messages') ) {
    $links[] = l('Inbox'. $new, 'messages/inbox');
  }
  if (user_access('read privatemsg') || user_access('read all private messages') ) {
    $links[] = l('Sent', 'messages/sent');
  }
  if ( count( $links ) ) {
    $block = array(
      'subject' => 'Private messages',
      'content' => theme('item_list', $links),
    );
  }
  return $block;
}
function privatemsg_form_alter(&$form, $form_state, $form_id) {
  switch ($form_id) {
    case 'privatemsg_new':
      if (arg(1) == 'view') {
        global $user;
        $subject = db_result(db_query('SELECT subject FROM {pm_message} WHERE mid = %d', arg(2)));
        $thread = db_result(db_query('SELECT thread_id FROM {pm_index} WHERE mid = %d', arg(2)));
        $query = _privatemsg_assemble_query('privatemsg_participants', $thread);
        $participants = db_query($query);
        $usercount = 0;
        while ($result = db_fetch_object($participants)) {
          if ($result->uid == $user->uid) {
            $usercount++;
            // Skip putting author in the recipients list for now.
            continue;
          }
          $to[] = db_result(db_query('SELECT name FROM {users} WHERE uid = %d', $result->uid));
        }

        if (empty($to) && $usercount >= 1) {
          // Assume the user sent message to own account as if the usercount is one or less, then the user sent a message but not to self.
          $to[] = db_result(db_query('SELECT name FROM {users} WHERE uid = %d', $user->uid));
        }
        if ($to) {
          $recipient = implode(', ', $to);
        }

        $form['thread_id'] = array(
          '#type' => 'hidden',
          '#value' => $thread,
        );
        $form['subject'] = array(
          '#type' => 'hidden',
          '#default_value' => $subject,
        );
        $form['recipient']  = array(
          '#type' => 'hidden',
          '#default_value' => $recipient,
        );
        $form['content']['body'] = array(
          '#type' => 'textarea',
          '#title' => t('Send reply to ' . $recipient),
          '#cols' => 10,
          '#rows' => 6,
          '#default_value' => isset($form_state['values']['body'])? $form_state['values']['body']: '',
        );
        // Remove the header set in privatemsg_new and also unset the cancel button.
        unset($form['header']);
        unset($form['controls']['cancel']);
      }
    break;
  }
}