<?php
// $Id: simplenews.module,v 1.76.2.24 2008-05-04 13:31:04 sutharsan Exp $

/**
 * @defgroup simplenews
 * Enable nodes to be used as newsletter, manage subscriptions and sent
 * email newsletter to subscribers.
 */
 
/**
 * @file
 * Simplnews node handling, sent email, newsletter block and general hooks
 *
 * @ingroup simplenews
 */

/**
 * NEWSLETTER MAIL PRIORITY
 */
define('SIMPLENEWS_PRIORITY_NONE', '0');
define('SIMPLENEWS_PRIORITY_HIGHEST', '1');
define('SIMPLENEWS_PRIORITY_HIGH', '2');
define('SIMPLENEWS_PRIORITY_NORMAL', '3');
define('SIMPLENEWS_PRIORITY_LOW', '4');
define('SIMPLENEWS_PRIORITY_LOWEST', '5');

/**
 * NEWSLETTER SEND COMMAND
 */
define('SIMPLENEWS_COMMAND_SEND_NONE', 0);
define('SIMPLENEWS_COMMAND_SEND_NOW', 1);
define('SIMPLENEWS_COMMAND_SEND_TEST', 2);

/**
 * NEWSLETTER SEND STATUS
 */
define('SIMPLENEWS_STATUS_SEND_NOT', 0);
define('SIMPLENEWS_STATUS_SEND_PENDING', 1);
define('SIMPLENEWS_STATUS_SEND_READY', 2);

define('SIMPLENEWS_CACHE_HOLD', 0);
define('SIMPLENEWS_CACHE_PENDING', 1);
define('SIMPLENEWS_CACHE_SEND', 2);

/**
 * Implementation of hook_node_info().
 */
function simplenews_node_info() {
  return array(
    'simplenews' => array(
      'name' => t('Newsletter issue'),
      'module' => 'simplenews',
      'description' => t('A newsletter issue to be sent to subscribed e-mail addresses.'),
    )
  );
}

/**
 * Implementation of hook_perm().
 */
function simplenews_perm() {
  return array('view links in block', 'create newsletter', 'edit own newsletter', 'edit any newsletter', 'delete own newsletter', 'delete any newsletter', 'administer newsletters', 'send newsletter', 'subscribe to newsletters');
}

/**
 * Implementation of hook_access().
 */
function simplenews_access($op, $node) {
  global $user;
  if ($op == 'create') {
    if (user_access('create newsletter')) {
      return TRUE;
    }
  }
  if ($op == 'update') {
    if (user_access('edit any newsletters')) {
      return TRUE;
    }
    elseif (user_access('edit own newsletter') && $user->uid == $node->uid) {
      return TRUE;
    }
  }
  if ($op == 'delete') {
    if (user_access('delete any newsletters')) {
      return TRUE;
    }
    elseif (user_access('delete own newsletter') && $user->uid == $node->uid) {
      return TRUE;
    }
  }
}

/**
 * Implementation of hook_init().
 */
function simplenews_init() {
  drupal_add_css(drupal_get_path('module', 'simplenews') .'/simplenews.css', 'module', 'all', TRUE);

  if (module_exists('views')) {
    include_once(drupal_get_path('module', 'simplenews') .'/simplenews_views.inc');
  }
}

/**
 * Implementation of hook_menu().
 */
function simplenews_menu() {
  $items['admin/content/newsletters'] = array(
    'title' => 'Newsletters',
    'description' => 'Manage newsletters, subscriptions, and configuration options.',
    'type' => MENU_NORMAL_ITEM,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('simplenews_admin_news'),
    'access arguments' => array('administer newsletters'),
    'file' => 'simplenews.admin.inc',
  );
  $items['admin/content/newsletters/sent'] = array(
    'title' => 'Sent issues',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'page arguments' => array('simplenews_admin_news'),
    'access arguments' => array('administer newsletters'),
    'file' => 'simplenews.admin.inc',
    'weight' => -10,
  );
  $items['admin/content/newsletters/notsent'] = array(
    'title' => 'Drafts',
    'type' => MENU_LOCAL_TASK,
    'page arguments' => array('simplenews_admin_news', 'notsent'),
    'access arguments' => array('administer newsletters'),
    'weight' => -9,
  );

  $items['admin/content/newsletters/types'] = array(
    'title' => 'Newsletters',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'simplenews_types_overview',
    'access arguments' => array('administer newsletters'),
    'file' => 'simplenews.admin.inc',
    'weight' => -8,
  );
  $items['admin/content/newsletters/types/edit/%'] = array(
    'title' => 'Newsletters',
    'type' => MENU_CALLBACK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('simplenews_admin_types_form', 5),
    'access arguments' => array('administer newsletters'),
    'file' => 'simplenews.admin.inc',
  );
  $items['admin/content/newsletters/types/delete/%'] = array(
    'title' => 'Newsletters',
    'type' => MENU_CALLBACK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('simplenews_admin_types_delete', 5),
    'access arguments' => array('administer newsletters'),
    'file' => 'simplenews.admin.inc',
  );
  $items['admin/content/newsletters/types/list'] = array(
    'title' => 'List newsletters',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'file' => 'simplenews.admin.inc',
    'weight' => -10,
  );
  $items['admin/content/newsletters/types/add'] = array(
    'title' => 'Add newsletter',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('simplenews_admin_types_form'),
    'access arguments' => array('administer newsletters'),
    'file' => 'simplenews.admin.inc',
    'weight' => -9,
  );
  $items['admin/content/newsletters/subscriptions/delete'] = array(
    'title' => 'Delete',
    'type' => MENU_CALLBACK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('simplenews_subscription_multiple_delete_confirm'),
    'access arguments' => array('administer newsletters'),
    'file' => 'simplenews.admin.inc',
  );
  $items['admin/content/newsletters/users'] = array(
    'title' => 'Subscriptions',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('simplenews_subscription_admin'),
    'access arguments' => array('administer newsletters'),
    'file' => 'simplenews.admin.inc',
    'weight' => -7,
  );
  $items['admin/content/newsletters/users/edit/%'] = array(
    'title' => 'Subscriptions',
    'type' => MENU_CALLBACK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('simplenews_admin_users_form', 5),
    'access arguments' => array('administer newsletters'),
    'file' => 'simplenews.subscription.inc',
    );
  $items['admin/content/newsletters/users/list'] = array(
    'title' => 'List subscriptions',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10,
  );
  $items['admin/content/newsletters/users/import'] = array(
    'title' => 'Import subscriptions',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('simplenews_subscription_list_add'),
    'access arguments' => array('administer newsletters'),
    'file' => 'simplenews.admin.inc',
    'weight' => -9,
  );
  $items['admin/content/newsletters/users/export'] = array(
    'title' => 'Export subscriptions',
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('simplenews_subscription_list_export'),
    'access arguments' => array('administer newsletters'),
    'file' => 'simplenews.admin.inc',
    'weight' => -8,
  );

  $items['admin/content/newsletters/settings'] = array(
    'title' => 'Settings',
    'type' => MENU_LOCAL_TASK,
    'page arguments' => array('simplenews_admin_settings'),
    'access arguments' => array('administer newsletters'),
    'weight' => -6,
  );
  $items['admin/content/newsletters/settings/general'] = array(
    'title' => 'General',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10,
  );
  $items['newsletter/confirm'] = array(
    'title' => 'Confirm newsletter subscriptions',
    'type' => MENU_CALLBACK,
    'page callback' => 'simplenews_confirm_subscription',
    'access arguments' => array('subscribe to newsletters'),
    'file' => 'simplenews.subscription.inc',
  );

  $items['newsletter/subscriptions'] = array(
    'title' => 'Manage newsletter subscriptions',
    'type' => MENU_CALLBACK,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('simplenews_subscription_manager_form'),
    'access arguments' => array('subscribe to newsletters'),
    'file' => 'simplenews.subscription.inc',
  );

  return $items;
}

/**
 * Implementation of hook_nodeapi().
 */
function simplenews_nodeapi(&$node, $op, $teaser, $page) {
  // We are going to return if $node->type is not one of the node
  // types assigned to the newsletter vocabulary. If simplenews_vid
  // is undefined or the vocabulary does not exist, it clearly cannot
  // be assigned to $node->type, so return to avoid E_ALL warnings.
  $vid = variable_get('simplenews_vid', '');
  $vocabulary = taxonomy_vocabulary_load($vid);
  if (empty($vocabulary)) {
    return;
  }

  // Operate only on node types assigned to the newsletter vocabulary.
  if (!in_array($node->type, $vocabulary->nodes)) {
    return;
  }

  switch ($op) {
    case 'view':
      $node = simplenews_replace_vars($node, TRUE);
      break;
    case 'validate':
      global $_simplenews_valid_mails;
      if ($node->simplenews['send'] == SIMPLENEWS_COMMAND_SEND_NOW) {
        if (!isset($node->taxonomy)) {
          form_set_error('', t('You should assign content type %content_type to the !newsletter_vocabulary before you can send this newsletter.', array('%content_type' => $node->type, '!newsletter_vocabulary' => l(t('Newsletter vocabulary'), 'admin/content/taxonomy'))));
        }
        elseif (!simplenews_validate_taxonomy($node->taxonomy)) {
          form_set_error('taxonomy', t('You should select a newsletter before you can send this newsletter issue.'));
        }
      }
      elseif ($node->simplenews['send'] == SIMPLENEWS_COMMAND_SEND_TEST) {
        $mails = explode(',', $node->simplenews['test_address']);
        foreach ($mails as $mail) {
          $mail = trim($mail);
          if ($mail == '') {
            form_set_error('simplenews][test_address', t('Cannot send test newsletter: no test e-mail address specified.'));
          }
          elseif (!valid_email_address($mail)) {
            form_set_error('simplenews][test_address', t('Cannot send test newsletter to %mail: e-mail address invalid.', array('%mail' => $mail)));
          }
        }
      }
      break;
    case 'presave':
      $term = simplenews_validate_taxonomy($node->taxonomy);
      $tid = is_array($term) ? array_values($term) : FALSE;
      $node->simplenews['tid'] = $tid ? $tid[0] : 0;
      break;
    case 'insert':
    case 'update':
      $send_with_permission = $node->simplenews['send'] == SIMPLENEWS_COMMAND_SEND_NOW && user_access('send newsletter');
      if ($op == 'insert') {
        // Insert node
        $s_status = $send_with_permission ? SIMPLENEWS_STATUS_SEND_PENDING : SIMPLENEWS_STATUS_SEND_NOT;
        db_query("INSERT INTO {simplenews_newsletters} (nid, vid, tid, s_status, s_format, priority, receipt)
                  VALUES (%d, %d, %d, %d, '%s', '%s', %d)", $node->nid, $node->vid, $node->simplenews['tid'], $s_status, $node->simplenews['s_format'], $node->simplenews['priority'], $node->simplenews['receipt']);
        }
      else {
        // Update node
        if ($send_with_permission) {
          db_query("UPDATE {simplenews_newsletters} SET vid = %d, tid = %d, s_status = %d, s_format = '%s', priority = '%s', receipt = %d
          WHERE nid = %d", $node->vid, $node->simplenews['tid'], SIMPLENEWS_STATUS_SEND_PENDING, $node->simplenews['s_format'], $node->simplenews['priority'], $node->simplenews['receipt'], $node->nid);
        }
        else {
          db_query("UPDATE {simplenews_newsletters} SET tid = %d, s_format = '%s', priority = '%s', receipt = %d
          WHERE nid = %d", $node->simplenews['tid'], $node->simplenews['s_format'], $node->simplenews['priority'], $node->simplenews['receipt'], $node->nid);
        }
      }

      // When translation module is activated all translated modules share the send status
      //TODO Share all states, not only send state
      if (module_exists('translation') && $send_with_permission) {
        if ($translations = translation_node_get_translations($node->tnid))  {
          foreach ($translations as $translation) {
            db_query("UPDATE {simplenews_newsletters} SET s_status = %d WHERE nid = %d", SIMPLENEWS_STATUS_SEND_PENDING, $translation->nid);
          }
        }
      }

      // Send newsletter or test newsletter
      if ($send_with_permission) {
        // Send newsletter to all subscribers
        simplenews_send_node($node);
      }
      elseif ($node->simplenews['send'] == SIMPLENEWS_COMMAND_SEND_TEST) {
        // Send test newsletter to test address(es)
        simplenews_send_test($node);
      }
      break;
    case 'delete':
      $result = db_query('DELETE FROM {simplenews_newsletters} WHERE nid = %d', $node->nid);
      if ($result) {
        drupal_set_message(t('Newsletter %title was successfully deleted.', array('%title' => $node->title)));
      }
      break;
    case 'load':
      $node->simplenews = db_fetch_array(db_query('SELECT * FROM {simplenews_newsletters} WHERE nid = %d', $node->nid));
      break;
  }
}

/**
 * Implementation of hook_form().
 */
function simplenews_form(&$node) {
  $type = node_get_types('type', $node);

  if ($type->has_title) {
    $form['title'] = array(
      '#type' => 'textfield',
      '#title' => check_plain($type->title_label),
      '#required' => TRUE,
      '#default_value' => $node->title,
      '#maxlength' => 255,
      '#weight' => -5,
    );
  }

  if ($type->has_body) {
    $form['body_field'] = node_body_field($node, $type->body_label, $type->min_word_count);
    // Available variables are based on user_mail_tokens().
    // But uses only those which can be used with uid = 0 since simplenews also sends to anonymous users.
    $form['body_field']['body']['#description'] = t('This will be the body of your newsletter. Available variables are:') . ' !site ' . t('(the name of your website),') . ' !uri ' . t('(a link to your homepage),') . ' !uri_brief ' . t('(homepage link without the http://),') . ' !date ' . t("(today's date),") . ' !login_uri ' . t('(link to login page).');
  }

  return $form;
}

/**
 * Validate if term is Newsletter taxonomy term.
 *
 * @return
 *   Array of selected Newsletter terms. Example: array(4, 12)
 *   FALSE: no Newsletter term is selected
 */
function simplenews_validate_taxonomy($taxonomy) {
  $vid = variable_get('simplenews_vid', '');
  $result = db_query('SELECT tid FROM {term_data} WHERE vid = %d', $vid);
  while ($tid = db_fetch_object($result)) {
    $tids[] = $tid->tid;
  }
  if (isset($tids) && !empty($taxonomy)) {
    $taxes = array();
    foreach ($taxonomy as $tax) {
      $taxes[] = $tax;
    }
    $selected_terms = array_intersect($tids, $taxes);
    return empty($selected_terms) ? FALSE : $selected_terms;
  }
  return FALSE;
}

/**
 * Implementation of hook_form_alter().
 */
function simplenews_form_alter(&$form, $form_state, $form_id) {
  $vid = variable_get('simplenews_vid', '');

  // Newsletter vocabulary form
  if ($form_id == 'taxonomy_form_vocabulary' && isset($form['vid']) && $form['vid']['#value'] == $vid) {
    // Hide critical options from newsletter vocabulary.
    $form['help_forum_vocab'] = array(
      '#value' => t('This is the designated simplenews vocabulary. This vocabulary can not be deleted.'),
      '#weight' => -1,
    );
    $form['content_types']['nodes']['#required'] = TRUE;
    $form['content_types']['nodes']['#description'] = t('Select content type(s) to be used as newsletter');
    $form['settings']['multiple'] = array('#type' => 'value', '#value' => FALSE);

    // Prevent the vocabulary gets deleted
    unset($form['delete']);
  }

  // Simplenews newsletter node form
  elseif (strpos($form_id, '_node_form') && isset($form['taxonomy'][$vid])) {
    if (isset($form['#node']->simplenews)) {
      $simplenews_values = $form['#node']->simplenews;
    }
    $form['simplenews'] = array(
      '#type' => 'fieldset',
      '#title' => t('Newsletter sending options'),
      '#collapsible' => TRUE,
      '#collapsed' => FALSE,
      '#tree' => TRUE,
    );
    // Hide format selection if there is nothing to choose
    if (count(_simplenews_format_options()) > 1) {
      $form['simplenews']['s_format'] = array(
        '#type' => 'select',
        '#title' => t('Format'),
        '#default_value' => $simplenews_values['s_format'],
        '#options' => _simplenews_format_options(),
      );
    }
    else {
      $form['simplenews']['s_format'] = array(
        '#type' => 'hidden',
        '#value' => variable_get('simplenews_format', 'plain'),
      );
    }

    $form['simplenews']['priority'] = array(
      '#type' => 'select',
      '#title' => t('Priority'),
      '#default_value' => isset($simplenews_values['priority']) ? $simplenews_values['priority'] : variable_get('simplenews_priority', SIMPLENEWS_PRIORITY_NONE),
      '#options' => array(
        SIMPLENEWS_PRIORITY_NONE => t('none'),
        SIMPLENEWS_PRIORITY_HIGHEST => t('highest'),
        SIMPLENEWS_PRIORITY_HIGH => t('high'),
        SIMPLENEWS_PRIORITY_NORMAL => t('normal'),
        SIMPLENEWS_PRIORITY_LOW => t('low'),
        SIMPLENEWS_PRIORITY_LOWEST => t('lowest'),
      ),
    );
    $form['simplenews']['receipt'] = array(
      '#type' => 'checkbox',
      '#title' => t('Request receipt'),
      '#return_value' => 1,
      '#default_value' => isset($simplenews_values['receipt']) ? $simplenews_values['receipt'] : variable_get('simplenews_receipt', 0),
    );
    if (!isset($simplenews_values['s_status']) || (isset($simplenews_values['s_status']) && $simplenews_values['s_status'] == SIMPLENEWS_STATUS_SEND_NOT)) {
      if (user_access('send newsletter')) {
        $options[SIMPLENEWS_COMMAND_SEND_NONE] = t("Don't send now");
        $options[SIMPLENEWS_COMMAND_SEND_TEST] = t('Send one test newsletter to the test address');
        $options[SIMPLENEWS_COMMAND_SEND_NOW] = t('Send newsletter');
        $form['simplenews']['send'] = array(
          '#type' => 'radios',
          '#title' => t('Sending'),
          '#default_value' => isset($simplenews_values['send']) ? $simplenews_values['send'] : variable_get('simplenews_send', SIMPLENEWS_COMMAND_SEND_NONE),
          '#options' => $options,
        );
      }
      else {
        $options[SIMPLENEWS_COMMAND_SEND_NONE] = t("Don't send now");
        $options[SIMPLENEWS_COMMAND_SEND_TEST] = t('Send one test newsletter to the test address');
        $form['simplenews']['send'] = array(
          '#type' => 'radios',
          '#title' => t('Sending'),
          '#default_value' => isset($simplenews_values['send']) ? $simplenews_values['send'] : SIMPLENEWS_COMMAND_SEND_NONE,
          '#options' => $options,
          '#description' => t('You have no privileges to send this newsletter'),
        );
      }
      $address_default = variable_get('site_mail', ini_get('sendmail_from'));
      if (variable_get('simplenews_test_address_override', 0)) {
        $form['simplenews']['test_address'] = array(
          '#type' => 'textfield',
          '#title' => t('Test e-mail addresses'),
          '#description' => t('Supply a comma-separated list of e-mail addresses to be used as test addresses.'),
          '#default_value' => isset($simplenews_values['test_address']) ? $simplenews_values['test_address'] : variable_get('simplenews_test_address', $address_default),
          '#size' => 60,
          '#maxlength' => 128,
        );
      }
      else {
        $form['simplenews']['test_address'] = array(
          '#type' => 'hidden',
          '#value' => variable_get('simplenews_test_address', $address_default),
        );
      }
    }
    else {
      $form['simplenews']['none'] = array(
        '#type' => 'checkbox',
        '#title' => t('This newsletter has been sent'),
        '#return_value' => 0,
        '#attributes' => array('checked' => 'checked', 'disabled' => 'disabled'),
      );
    }
    $form['simplenews']['s_status'] = array(
      '#type' => 'hidden',
      '#value' => isset($simplenews_values['s_status']) ? $simplenews_values['s_status'] : SIMPLENEWS_STATUS_SEND_NOT,
    );
  }
}

/**
 * Implementation of hook_cron().
 */
function simplenews_cron() {
  simplenews_mail_send();
}

/**
 * Implementation of hook_taxonomy().
 *
 * Deletes subscriptions to term when term is deleted, and cleans the blocks
 * table.
 */
function simplenews_taxonomy($op, $type, $term = NULL) {
  if ($op == 'delete' && $term['vid'] == variable_get('simplenews_vid', '')) {
    switch ($term) {
      case 'term':
        db_query('DELETE FROM {simplenews_snid_tid} WHERE tid = %d', $array['tid']);
        db_query("DELETE FROM {blocks} WHERE module = '%s' AND delta = '%s'", 'simplenews', $term['tid']);
        drupal_set_message(t('Deleted all subscriptions to newsletter %newsletter.', array('%newsletter' => $term['name'])));
        break;
    }
  }
}

/**
 * Implementation of hook_user().
 *
 * Checks whether an email address is subscribed to the newsletter when a new
 * user signs up. If so, changes uid from 0 to the new uid in
 * simplenews_subscriptions so that the user's subscription status is known when
 * he logs in.
 */
function simplenews_user($op, &$edit, &$account, $category = NULL) {
  switch ($op) {
    case 'insert':
      if ($edit['mail']) {
        $query = "SELECT snid FROM {simplenews_subscriptions} WHERE mail = '%s'";
        if ($result = db_fetch_object(db_query($query, $edit['mail']))) {
          db_query("UPDATE {simplenews_subscriptions} SET uid = %d WHERE snid = %d", $edit['uid'], $result->snid);
        }
      }
      break;
    case 'update':
      if ($category == 'account' && $edit['mail']) {
        $query = "SELECT snid FROM {simplenews_subscriptions} WHERE uid = %d";
        if ($result = db_fetch_object(db_query($query, $account->uid))) {
          db_query("DELETE FROM {simplenews_subscriptions} WHERE mail = '%s' AND uid = %d", $edit['mail'], 0);
          db_query("UPDATE {simplenews_subscriptions} SET mail = '%s' WHERE snid = %d", $edit['mail'], $result->snid);
        }
        else {
          $query = "SELECT snid FROM {simplenews_subscriptions} WHERE mail = '%s'";
          if ($result = db_fetch_object(db_query($query, $edit['mail']))) {
            db_query("UPDATE {simplenews_subscriptions} SET uid = %d WHERE snid = %d", $account->uid, $result->snid);
          }
        }
      }

       // Activate/deactivate subscription when account is blocked/unblocked
       if ($category == 'account' && isset($edit['status'])) {
         if (variable_get('simplenews_sync_account', TRUE)) {
           db_query("UPDATE {simplenews_subscriptions} SET activated = %d WHERE uid = %d", $edit['status'], $account->uid);
         }
       }

       if ($category == 'newsletter' && user_access('subscribe to newsletters')) {
        foreach ($edit['newsletters'] as $tid => $checked) {
          if ($checked) {
            simplenews_subscribe_user($account->mail, $tid, FALSE);
          }
          else {
            simplenews_unsubscribe_user($account->mail, $tid, FALSE);
          }
        }
      }
      break;
    case 'delete':     
      if (variable_get('simplenews_sync_account', TRUE)) {
        // Delete subscription and all newsletter subscriptions when account is removed
        $subscription = simplenews_get_user_subscription($account->mail);
        db_query('DELETE FROM {simplenews_snid_tid} WHERE snid = %d', $subscription->snid);
        db_query('DELETE FROM {simplenews_subscriptions} WHERE snid = %d', $subscription->snid);        
      }
      else {
        // Only remove uid from subscription data when account is removed
        db_query("UPDATE {simplenews_subscriptions} SET uid = 0 WHERE uid = %d", $account->uid);
      }
      break;
    case 'form':
      if ($category == 'newsletter' && user_access('subscribe to newsletters')) {
        $subscription = simplenews_get_subscription($account);
        $form = _simplenews_subscription_manager_form($subscription);
        $form['subscriptions']['#title'] =  t('Current newsletter subscriptions');
        unset($form['update'], $form['subscriptions']['mail']);
        return $form;
      }
      break;
    case 'categories':
      if (user_access('subscribe to newsletters')) {
        $output[] = array('name' => 'newsletter', 'title' => t('My newsletters'), 'weight' => 10);
      }
      return $output;
    case 'view':
      global $user;
      if ($user->uid == $account->uid || user_access('administer users')) {
        $account->content['simplenews'] = array(
          '#type' => 'user_profile_category',
          '#title' => t('Newsletters'),
        );
        $tree = taxonomy_get_tree(variable_get('simplenews_vid', ''));
        foreach ($tree as $newsletter) {
          if (db_result(db_query('SELECT COUNT(s.uid) FROM {simplenews_subscriptions} s INNER JOIN {simplenews_snid_tid} t ON s.snid = t.snid WHERE s.uid = %d AND t.tid = %d', $account->uid, $newsletter->tid))) {
            $subscriptions[] = l($newsletter->name, 'taxonomy/term/'. $newsletter->tid);
          }
        }
        if (isset($subscriptions)) {
          $subscriptions = implode(', ', $subscriptions);
        }
        else {
          $subscriptions = t('None');
        }
        $account->content['simplenews']['subscriptions'] = array(
          '#type' => 'user_profile_item',
          '#title' => t('Current subscriptions'),
          '#value' => $subscriptions,
        );
        if (user_access('subscribe to newsletters')) {
          $account->content['simplenews']['my_newsletters'] = array(
            '#type' => 'user_profile_item',
            '#value' => t('Manage !my_subscriptions', array('!my_subscriptions' => l(t('my subscriptions'), 'user/'. $account->uid .'/edit/newsletter'))),
            '#weight' => -1,
          );
        }
        return array(t('Newsletters') => $items);
      }
      break;
  }
}

/**
 * Implementation of hook_block().
 */
function simplenews_block($op = 'list', $delta = 0, $edit = array()) {
  switch ($op) {
    case 'list':
      $blocks = array();
      foreach (taxonomy_get_tree(variable_get('simplenews_vid', '')) as $newsletter) {
        //TODO: 1. without form -> by role; 2. with form -> user caching with refresh on subscribe/unsubscribe (option as setting) or no caching
        $blocks[$newsletter->tid] = array(
          'info' => t('Newsletter: @title', array('@title' => $newsletter->name)),
          'cache' => variable_get('simplenews_block_f_'. $newsletter->tid, 1) ? BLOCK_NO_CACHE : BLOCK_CACHE_PER_ROLE,
        );
      }
      return $blocks;
    case 'configure':
      $form['simplenews_block_'. $delta]['simplenews_block_m_status_'. $delta] = array(
        '#type' => 'checkbox',
        '#title' => t('Display block message'),
        '#return_value' => 1,
        '#default_value' => variable_get('simplenews_block_m_status_'. $delta, 1),
      );
      $form['simplenews_block_'. $delta]['simplenews_block_m_'. $delta] = array(
        '#type' => 'textfield',
        '#title' => t('Block message'),
        '#size' => 60,
        '#maxlength' => 128,
        '#default_value' => variable_get('simplenews_block_m_'. $delta, t('Stay informed on our latest news!')),
      );
      $form['simplenews_block_'. $delta]['simplenews_block_f_'. $delta] = array(
        '#type' => 'checkbox',
        '#title' => t('Display subscription form'),
        '#return_value' => 1,
        '#description' => t('If selected a subscription form is displayed, if not selected a link to the subscription page is displayed.'),
        '#default_value' => variable_get('simplenews_block_f_'. $delta, 1),
      );
      $form['simplenews_block_'. $delta]['simplenews_block_l_'. $delta] = array(
        '#type' => 'checkbox',
        '#title' => t('Display link to previous issues'),
        '#return_value' => 1,
        '#default_value' => variable_get('simplenews_block_l_'. $delta, 1),
        '#description' => t('Links (to previous issues, previous issues and RSS-feed) are only displayed to users who have "view links in block" privileges.'),
      );
      $form['simplenews_block_'. $delta]['simplenews_block_i_status_'. $delta] = array(
        '#type' => 'checkbox',
        '#title' => t('Display previous issues'),
        '#return_value' => 1,
        '#default_value' => variable_get('simplenews_block_i_status_'. $delta, 0),
      );
      $form['simplenews_block_'. $delta]['simplenews_block_i_'. $delta] = array(
        '#type' => 'select',
        '#title' => t('Number of issues to display'),
        '#options' => drupal_map_assoc(array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)),
        '#default_value' => variable_get('simplenews_block_i_'. $delta, 5),
      );
      $form['simplenews_block_'. $delta]['simplenews_block_r_'. $delta] = array(
        '#type' => 'checkbox',
        '#title' => t('Display RSS-feed icon'),
        '#return_value' => 1,
        '#default_value' => variable_get('simplenews_block_r_'. $delta, 1),
      );
      return $form;
    case 'save':
        variable_set('simplenews_block_m_status_'. $delta, $edit['simplenews_block_m_status_'. $delta]);
        variable_set('simplenews_block_m_'. $delta, $edit['simplenews_block_m_'. $delta]);
        variable_set('simplenews_block_f_'. $delta, $edit['simplenews_block_f_'. $delta]);
        variable_set('simplenews_block_l_'. $delta, $edit['simplenews_block_l_'. $delta]);
        variable_set('simplenews_block_i_status_'. $delta, $edit['simplenews_block_i_status_'. $delta]);
        variable_set('simplenews_block_i_'. $delta, $edit['simplenews_block_i_'. $delta]);
        variable_set('simplenews_block_r_'. $delta, $edit['simplenews_block_r_'. $delta]);
        break;
    case 'view':
      if ($newsletter = (array) taxonomy_get_term($delta)) {
        $block = array(
          'subject' => check_plain($newsletter['name']),
          'content' => theme('simplenews_block', $newsletter['tid']),
        );
      }
      return $block;
  }
}

/**
 * Load a user or creates a dummy anonymous user.
 *
 * @return account
 *   object (
 *     mail,   e-mail address
 *     uid,    uid or 0 for anonymous
 *   )
 */
function _simplenews_user_load($mail) {
  $account = user_load(array('mail' => $mail));
  if ($account === FALSE) {
    // Construct anonymous user since we don't have a user that matches that e-amil.
    $account = new stdClass();
    $account->uid = 0;
    $account->mail = $mail;
  }
  return $account;
}

/**
 * Subscribe a user to a newsletter or send a confirmation mail.
 *
 * The $confirm parameter determines the action:
 *   FALSE = The user is subscribed
 *   TRUE  = User receives an email to verify the address and complete the subscription
 * A new subscription account is created when the user is subscribed to the first newsletter
 *
 * @param string $mail The e-mail address to subscribe to the newsletter.
 * @param integer $tid The term ID of the newsletter.
 * @param boolean $confirm TRUE = send confirmation mail; FALSE = subscribe immediate to the newsletter
 */
function simplenews_subscribe_user($mail, $tid, $confirm = TRUE) {
  //Prevent mismatches from accidental capitals in mail address
  $mail = strtolower($mail);

  $account = (object) array('mail' => $mail);
  $subscription = simplenews_get_subscription($account);

  // If user is not subscribed to ANY newsletter, create a subscription account
  if ($subscription->snid == 0) {
    // To subscribe a user:
    //   1. Fetch the users uid.
    //   2. Add the user to the database.
    //   3. Get the full subscription object based on the mail address.
    // Note that step 3 gets subscription data based on mail address because the uid can be 0 (for anonymous users)
    $account = _simplenews_user_load($mail);
    db_query("INSERT INTO {simplenews_subscriptions} (mail, uid, activated) VALUES ('%s', %d, %d)", $mail, $account->uid, 1);
    $subscription = simplenews_get_subscription($account);
  }

  if ($confirm) {
    // Send confirmation e-mail to user to complete subscription or to tell
    // them that he or she is already subscribed.
    // Confirmation mail is in the user preferred language which is by default the language_default().
    $params['from'] = _simplenews_set_from();
    $params['newsletter'] = taxonomy_get_term($tid);
    $params['context']['account'] = $subscription;
    drupal_mail('simplenews', 'subscribe', $mail, $subscription->language, $params);
  }
  elseif (!isset($subscription->tids[$tid])) {
    // OR add user to newsletter relationship if not already subscribed.
    db_query("INSERT INTO {simplenews_snid_tid} (snid, tid) VALUES (%d, %d)", $subscription->snid, $tid);
  }
  return TRUE;
}

/**
 * Unsubscribe a user from a newsletter or send a confirmation mail.
 *
 * The $confirm parameter determines the action:
 *   FALSE = The user is unsubscribed
 *   TRUE  = User receives an email to verify the address and complete the unsubscription
 * The subscription account is deleted when the user is unsubscribed to the last newsletter
 *
 * @param string $mail The e-mail address to unsubscribe from the newsletter.
 * @param integer $tid The term ID of the newsletter.
 * @param boolean $confirm TRUE = send confirmation mail; FALSE = unsubscribe immediate from the newsletter
 */
function simplenews_unsubscribe_user($mail, $tid, $confirm = TRUE) {
  //Prevent mismatches from accidental capitals in mail address
  $mail = strtolower($mail);

  $account = (object) array('mail' => $mail);
  $subscription = simplenews_get_subscription($account);

  // The unlikely case that a user is subscribed from a non existing newsletter is logged
  if (!$newsletter = taxonomy_get_term($tid)) {
    watchdog('simplenews', 'Attempt to unsubscribe from non existing newsletter term ID %id', array('%id' => $tid), WATCHDOG_ERROR);
    return FALSE;
  }

  if ($confirm) {
    // Send confirmation e-mail to user to complete unsubscription
    // or to tell them that he or she is not subscribed
    // Confirmation mail is in the user preferred language.
    $params['from'] = _simplenews_set_from();
    $params['newsletter'] = $newsletter;
    $params['context']['account'] = $subscription;
    drupal_mail('simplenews', 'unsubscribe', $mail, $subscription->language, $params);
  }
  elseif (isset($subscription->tids[$tid])) {
    // OR remove the user from the newsletter.
    db_query('DELETE FROM {simplenews_snid_tid} WHERE snid = %d AND tid = %d', $subscription->snid, $tid);

    // Clean up subscription account if user is not subscribed to any newsletter anymore
    if (!db_result(db_query("SELECT COUNT(*) FROM {simplenews_snid_tid} t WHERE t.snid = %d", $subscription->snid))) {
      db_query('DELETE FROM {simplenews_subscriptions} WHERE snid = %d', $subscription->snid);
    }
  }

  return TRUE;
}

/**
 * Check if the e-mail address is subscribed to the given newsletter.
 *
 * @param string $mail email address
 * @param integer $tid newsletter term id
 *
 * @return boolean TRUE = email address is subscribed to given newsletter term id
 */
function simplenews_user_is_subscribed($mail, $tid) {
  return db_result(db_query("SELECT COUNT(*) FROM {simplenews_subscriptions} s INNER JOIN {simplenews_snid_tid} t ON s.snid = t.snid WHERE s.mail = '%s' AND t.tid = %d", $mail, $tid)) ? TRUE : FALSE;
}

/**
 * Get the subscription object for the given account.
 *
 * Account is defined by (in order of preference) snid, e-mail address or uid.
 * If the account is not subscribed a default subscription object is returned
 * containing all available account info.
 *
 * @param object $account account details. Containing one or none of these items:
 *  object(
 *    snid :  subscription id
 *    mail :  e-mail address
 *    uid  :  user id
 *  )
 *
 * @return subscription object
 *   object(
 *     snid :  subscription id. 0 if account is not subscribed
 *     tids :  array of newsletter tid's
 *     uid  :  user id. 0 if account is anonymous user
 *     mail :  user e-mail address. empty if e-mail is unknown
 *     name :  always empty. Added for compatebility with user account object
 *     language : language object. User preferred or default language
 *   )
 */
function simplenews_get_subscription($account) {
  // Load subscription data based on available account informatioin
  // NOTE that the order of checking for snid, mail and uid is critical. mail must be checked *before* uid. See simplenews_subscribe_user()
  if (isset($account->snid)) {
    $subscription = db_fetch_object(db_query("SELECT s.*, u.language FROM {simplenews_subscriptions} s INNER JOIN {users} u ON u.uid = s.uid WHERE s.snid = %d", $account->snid));
  }
  elseif (isset($account->mail)) {
    $subscription = db_fetch_object(db_query("SELECT s.*, u.language FROM {simplenews_subscriptions} s INNER JOIN {users} u ON u.uid = s.uid WHERE s.mail = '%s'", $account->mail));
  }
  elseif (isset($account->uid)) {
    $subscription = db_fetch_object(db_query("SELECT s.*, u.language FROM {simplenews_subscriptions} s INNER JOIN {users} u ON u.uid = s.uid WHERE s.uid = %d", $account->uid));
  }

  if ($subscription) {
    $result = db_query("SELECT tid FROM {simplenews_snid_tid} t WHERE t.snid = %d", $subscription->snid);
    $subscription->tids = array();
    while ($newsletter = db_fetch_object($result)) {
      $subscription->tids[$newsletter->tid] = $newsletter->tid;
    }
    $subscription->name = '';
    $subscription->language = user_preferred_language($subscription, language_default());
  }
  else {
    // Account is unknown in subscription table. Create default subscription object
    $subscription = new stdClass();
    $subscription->name = '';
    $subscription->uid = isset($account->uid) ? $account->uid : 0;
    $subscription->mail = isset($account->mail) ? $account->mail : '';
    $subscription->language = language_default();
    $subscription->snid = 0;
    $subscription->tids = array();
  }
  return $subscription;
}

/**
 * Delete every subscription for the given subscription ID.
 *
 * @param integer $snid subscription id
 */
function simplenews_delete_subscription($snid) {
  $account = db_fetch_object(db_query('SELECT mail FROM {simplenews_subscriptions} WHERE snid = %d', $snid));
  db_query('DELETE FROM {simplenews_subscriptions} WHERE snid = %d', $snid);
  db_query('DELETE FROM {simplenews_snid_tid} WHERE snid = %d', $snid);
  watchdog('simplenews', 'User %email deleted from the mailing list.', array('%email' => $account->mail), WATCHDOG_NOTICE);
}

/**
 * Build subscription manager form.
 *
 * @param object $subscription subscription object
 */
function _simplenews_subscription_manager_form($subscription) {
  $form = array();
  $options = array();
  foreach (taxonomy_get_tree(variable_get('simplenews_vid', '')) as $newsletter) {
    $options[$newsletter->tid] = $newsletter->name;
    $default_value[$newsletter->tid] = FALSE;
  }

  $form['subscriptions'] = array(
    '#type' => 'fieldset',
    '#description' => t('Select the newsletter(s) to which you want to subscribe or unsubscribe.'),
  );
  $form['subscriptions']['newsletters'] = array(
    '#type' => 'checkboxes',
    '#options' => $options,
    '#default_value' => array_merge($default_value, (array)$subscription->tids),
  );

  // If current user is logged in, just display e-mail.
  // Anonymous users see an e-mail box and will receive confirmations
  if ($subscription->mail) {
    $form['subscriptions']['#title'] = t('Subscriptions for %mail', array('%mail' => $subscription->mail));
    $form['subscriptions']['mail'] = array('#type' => 'value', '#value' => $subscription->mail);
    $form['update'] = array(
      '#type' => 'submit',
      '#value' => t('Update'),
      '#weight' => 20,
    );
  }
  else {
    $form['subscriptions']['#title'] = t('Manage your newsletter subscriptions');
    $form['subscriptions']['mail'] = array(
      '#type' => 'textfield',
      '#title' => t('E-mail'),
      '#size' => 20,
      '#maxlength' => 128,
      '#weight' => 10,
      '#required' => TRUE,
    );
    $form['subscribe'] = array(
      '#type' => 'submit',
      '#value' => t('Subscribe'),
      '#weight' => 20,
    );
    $form['unsubscribe'] = array(
      '#type' => 'submit',
      '#value' => t('Unsubscribe'),
      '#weight' => 30,
    );
  }
  return $form;
}

/**
 * Create a list of recent newsletters.
 *
 * @param integer $tid term id of selected newsletter
 * @param integer $count number of newsletters in the list
 */
function simplenews_recent_newsletters($tid, $count = 5) {
  $result = db_query_range(db_rewrite_sql('SELECT n.nid, n.title, sn.s_status FROM {node} n INNER JOIN {term_node} t ON n.vid = t.vid INNER JOIN {simplenews_newsletters} sn ON n.nid = sn.nid WHERE (t.tid = %d AND n.status = %d) ORDER BY n.created DESC'), $tid, 1, 0, $count);
  $titles = array();
  while ($item = db_fetch_object($result)) {
    $titles[$item->nid]['data'] = l($item->title, 'node/'. $item->nid);
    $titles[$item->nid]['class'] = ($item->s_status == SIMPLENEWS_STATUS_SEND_NOT) ? 'newsletter-created' : 'newsletter-send';
  }
  return $titles;
}

/**
 * Newsletter (un)subscription form for authenticated and anonymous users.
 *
 * @param $tid term id of selected newsletter.
 *
 * @see simplenews_block_form_validate()
 * @see simplenews_block_form_submit()
 */
function simplenews_block_form(&$form_state, $tid) {
  global $user;
  $form = array();

  if ($user->uid) {
    if (simplenews_user_is_subscribed($user->mail, $tid)) {
      $submit_text = t('Unsubscribe');
      $form['action'] = array('#type' => 'value', '#value' => 'unsubscribe');
    }
    else {
      $submit_text = t('Subscribe');
      $form['action'] = array('#type' => 'value', '#value' => 'subscribe');
    }
    $form['display_mail'] = array(
      '#type' => 'item',
      '#title' => t('User'),
      '#value' => check_plain($user->name),
    );
    $form['mail'] = array('#type' => 'value', '#value' => $user->mail);
  }
  else {
    $form['mail'] = array(
      '#type' => 'textfield',
      '#title' => t('E-mail'),
      '#size' => 20,
      '#maxlength' => 128,
      '#required' => TRUE,
    );
    $form['action'] = array(
      '#type' => 'radios',
      '#default_value' => 'subscribe',
      '#options' => array('subscribe' => t('Subscribe'), 'unsubscribe' => t('Unsubscribe')),
    );
  }
  $form['#tid'] = $tid;
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => isset($submit_text) ? $submit_text : t('Save')
  );
  return $form;
}

function simplenews_block_form_validate($form, &$form_state) {
  if (!valid_email_address($form_state['values']['mail'])) {
    form_set_error('mail', t("The e-mail address you supplied is not valid."));
  }
}

function simplenews_block_form_submit($form, &$form_state) {
  global $user;
  $tid = $form['#tid'];
  $account = _simplenews_user_load($form_state['values']['mail']);

  // If e-mail belongs to the current registered user, don't send confirmation.
  $confirm = $account->uid && $account->uid == $user->uid ? FALSE : TRUE;

  switch ($form_state['values']['action']) {
    case 'subscribe':
      simplenews_subscribe_user($form_state['values']['mail'], $tid, $confirm);
      if ($confirm) {
        drupal_set_message(t('You will receive a confirmation e-mail shortly containing further instructions on how to complete your subscription.'));
      }
      else {
        drupal_set_message(t('You have been successfully subscribed.'));
      }
      break;
    case 'unsubscribe':
      simplenews_unsubscribe_user($form_state['values']['mail'], $tid, $confirm);
      if ($confirm) {
        drupal_set_message(t('You will receive a confirmation e-mail shortly containing further instructions on how to complete the unsubscription process.'));
      }
      else {
        drupal_set_message(t('You have been successfully unsubscribed.'));
      }
      break;
  }
}

/**
 * Send newsletter node to subcribers.
 *
 * @param integer or object $node Newsletter node to be send. integer = nid; object = node object
 * @param array $accounts  account objects to send the newsletter to.
 *   account = object (
 *     snid     = subscription id. 0 if no subscription record exists
 *     tids     = array(tid) array of newsletter tid's
 *     uid      = user id. 0 if subscriber is anonymous user.
 *     mail     = user e-mail address.
 *     name     = <empty>. Added for compatebility with user account object
 *     language = language object. User preferred of default language
 *   )
 *   NOTE: either snid, mail or uid is required.
 */
function simplenews_send_node($node, $accounts = array()) {
  if (is_numeric($node)) {
    $node = node_load($node);
  }
  if (is_object($node)) {
    $from = _simplenews_set_from($node);
    $params['context']['node'] = $node;
    $params['from'] = $from;

    if (empty($accounts)) {
      // No accounts specified. Send message to all accounts subscribed to this newsletter.
      // Account data is taken directly from simplenews_subscriptions table. simplenews_get_subscription() is not used because it is not (yet) optimized for multiple subscribers.
      // Name and language are added because this data is not (yet) in the table.
      $tid = $node->simplenews['tid'];
      $result = db_query('SELECT s.mail, s.snid, u.language FROM {simplenews_subscriptions} s INNER JOIN {simplenews_snid_tid} t ON s.snid = t.snid INNER JOIN {users} u ON s.uid = u.uid WHERE s.activated = %d AND t.tid = %d ORDER BY s.snid ASC', 1, $tid);
      while ($account = db_fetch_object($result)) {
        // Add values to account which currently do not exist in the simplenews_subscription table to match the $user account object
        $account->name = '';
        $account->language = user_preferred_language($account);
        $accounts[] = $account;
      }
    }
    else {
      // Send newsletter to specified accounts.
      // Account data is gathered based on the supplied uid or email address.
      foreach ($accounts as $account) {
        $subscriptions[] = simplenews_get_subscription($account);
      }
      $accounts = $subscriptions;
    }

    // Mail is send directly (simplenews_use_cron = FALSE) or stored in a mail cache (simplenews_use_cron = TRUE)
    // Cached emails are send by simplenews_mail_send() on each cron run
    foreach ($accounts as $account) {
      $params['context']['account'] = $account;
      $message = drupal_mail('simplenews', 'node', $account->mail, $account->language, $params, $from['formatted'], !variable_get('simplenews_use_cron', TRUE));
      if (variable_get('simplenews_use_cron', TRUE)) {
        // Chache newsletter mail messages
        simplenews_mail_cache_set($message);
      }
      else {
        if (variable_get('simplenews_debug', FALSE)) {
          watchdog('simplenews', 'Outgoing email. Message type: %type<br />Subject: %subject<br />Recipient: %to', array('%type' => $key, '%to' => $message['to'], '%subject' => $message['subject']), WATCHDOG_DEBUG);
        }
      }
    }
  }
}

/**
 * Send test version of newsletter.
 *
 * @param integer or object $node Newsletter node to be send. Integer = nid; Object = node object
 * @param array $accounts account objects to send the test newsletter to.
 *                  account = object(
 *                    mail : e-mail address of recipient
 *                  )
 */
function simplenews_send_test($node, $accounts = array()) {
  if (is_numeric($node)) {
    $node = node_load($node);
  }
  if (is_object($node)) {
    $from = _simplenews_set_from($node);
    $params['context']['node'] = $node;
    $params['from'] = $from;

    // If no account is specified the test newsletter is send to the test address(es) specified in the node.
    if (empty($accounts)) {
      // Build array of test e-mail addresses
      $mails = explode(',', $node->simplenews['test_address']);
      foreach ($mails as $mail) {
        $account['mail'] = trim($mail);
        $accounts[] = (object)$account;
      }
    }

    // Test emails are send directly by drupal_mail(). This in contrast to simplenews_send_node() which send via a buffer.
    foreach ($accounts as $account) {
      $subscription = simplenews_get_subscription($account);
      $params['context']['account'] = $subscription;
      $result = drupal_mail('simplenews', 'test', $account->mail, $subscription->language, $params, $from['formatted']);
      if ($result['result']) {
        drupal_set_message(t('Test newsletter sent to %recipient.', array('%recipient' => $account->mail)));
      }
    }
  }
}

/**
 * Implementation of hook_mail.
 * 
 * Send simplenews mails using drupal mail API
 * @see drupal_mail()
 *
 * @param $key: node | test | subscribe | unsubscribe
 * @param array $message message array
 *          [from]
 *          [headers][From]
 * @param array $params parameter array
 *          [context][node]       : node object of message to be send
 *          [context][snid]       : used for $key = subscribe or unsubscribe
 *          [context][from_name]  : name of mail sender or site name (optional)
 *          [context][account]    : account details of recipient
 *          [from]                : array('address' => 'noreply@example.org', 'formatted' =>  'site name <noreply@example.org>')
 *          [newsletter]          : newsletter object (tid, name)
 *          [tokens]              : tokens for variable replacement. Defaults to: user_mail_tokens()
 */
function simplenews_mail($key, &$message, $params) {
  $context = $params['context'];

  switch ($key) {
    case 'node':
    case 'test':

      // Message header, body and mail headers are buffered to increase
      // perfomance when sending multiple mails. Buffered data only contains
      // general data, no recipient specific content. Placeholders are used
      // for recipient data and will later be replaced.
      // When mailing multiple newsletters in one page call or cron run,
      // data is once stored and subsequently retreived from the
      // static $messages variable.
      // $message buffer is node and language specific.
      static $messages = array();

      $nid = $context['node']->nid;
      $langcode = $message['language']->language;
      if (module_exists('translation')) {

        // If the node has translations and a translation is required
        // the equivalent of the node in the required langugage is used
        // or the base node (tnid) is used
        if ($tnid = $context['node']->tnid) {
          if ($langcode != $context['node']->language) {
            $translations = translation_node_get_translations($tnid);
            if ($translation = $translations[$langcode]) {
              $nid = $translation->nid;
              $langcode = $translation->language;
            }
            else {
              // No translation found which matches the required language
              // Base node ($tnid) is used. The matching language replaces
              // the required language.
              foreach ($translations as $translation) {
                if ($translation->nid == $tnid) {
                  $nid = $tnid;
                  $langcode = $translation->language;
                  break;
                }
              }
            }
          }
        }

        // If a different node is selected and this node is not available in
        // the message buffer, the selected node load will replace the original.
        if ($nid != $context['node']->nid && !isset($messages[$nid][$langcode])) {
          $context['node'] = node_load($nid);
        }
      }

      if (!isset($messages[$nid][$langcode])) {
        $node = $context['node'];

        // Add simplenews specific header data
        $headers = array_merge($message['headers'], _simplenews_headers($node, $params['from']['address']));
        $message['headers'] = $messages[$nid][$langcode]['headers'] = $headers;

        // Build message subject
        if ($tid = $node->simplenews['tid']) {
          $term = taxonomy_get_term($tid);
          $name = check_plain($term->name);
        }
        else {
          $name = t('Unassigned newsletter');
        }
        $subject = theme('simplenews_newsletter_subject', $name, check_plain($node->title), $langcode);
        $subject = str_replace(array("\r", "\n"), '', $subject);
        $message['subject'] = $messages[$nid][$langcode]['subject'] = $subject;

        // Build message body
        // Processing node body mimics node_view() with full node view
        $node = node_build_content($node, FALSE, TRUE);
        $content = drupal_render($node->content);
        $node->body = $content;
        unset($node->teaser);
        node_invoke_nodeapi($node, 'alter', FALSE, TRUE);
        $node = node_prepare($node);
        $body = theme('simplenews_newsletter_body', $node->body, check_plain($node->title), $langcode);

        // Buffer body text node and language specific
        $messages[$nid][$langcode]['body'] = $body;

      }
      else {
        // Retreived headers, subject and raw body from the buffer
        $message['headers'] = $messages[$nid][$langcode]['headers'];
        $message['subject'] = $messages[$nid][$langcode]['subject'];
        $body = $messages[$nid][$langcode]['body'];
      }

      $variables =  user_mail_tokens($context['account'], $context['account']->language);
      $body = strtr($body, $variables);
      $body = simplenews_html_to_text($body);
      $message['body']['body'] = $body;

      // Build message footer
      if ($key == 'node' && isset($context['account']->snid)) {
        $hash = _simplenews_generate_hash($context['account']->mail, $context['account']->snid, $node->newsletter['tid']);
      }
      else {
        $hash = '';
      }
      $message['headers']['List-Unsubscribe'] = '<'. url('newsletter/confirm/remove/'. $hash, array('absolute' => TRUE)) .'>';
      $message['body']['footer'] = theme('simplenews_newsletter_footer', $node->simplenews['s_format'], $hash, $key == 'test', $langcode);
      break;
    case 'subscribe':
    case 'unsubscribe':
      if (isset($context['account']->snid) && isset($params['newsletter']->tid)) {
        $hash = _simplenews_generate_hash($context['account']->mail, $context['account']->snid, $params['newsletter']->tid);
      }
      else {
        $hash = NULL;
      }

      // Replace default site address with formatted simplenews from address
      $message['headers']['From'] = $message['headers']['Reply-To'] = $params['from']['formatted'];

      //TODO: Too much logic in this theme function! Split it or move the text here without theming. Additional variable replacement needed.
      $langcode = $context['account']->language->language;
      $subject = theme('simplenews_newsletter_confirmation_subject', $params['newsletter'], variable_get('simplenews_from_name', $name_default), $langcode);
      $message['subject'] = str_replace(array("\r", "\n"), '', $subject);

      $message['body'] = theme('simplenews_newsletter_confirmation_body', $context['account']->mail, $params['newsletter'], $key, $hash, $langcode);
      break;
  }

  // Debug message to check for outgoing emails messages.
  // Newsletters ($key = 'node') are not send now. Debugging will take place in simplenews_mail_send() when the newsletters are send
  if (variable_get('simplenews_debug', FALSE) && $key != 'node') {
    watchdog('simplenews', 'Outgoing email. Message type: %type<br />Subject: %subject<br />Recipient: %to', array('%type' => $key, '%to' => $message['to'], '%subject' => $message['subject']), WATCHDOG_DEBUG);
  }

}

/**
 * Mailing 'backend' for simplenews newsletters.
 *
 * Newsletters are formatted and buffered per recipient in database cache.
 * Sending is initiated by cron
 * Messages are retreived from the database cache and send one by one
 * If sending is succesful the message is removed from the database cache.
 */
function simplenews_mail_send() {

  // Send pending messages from database cache
  // A limited number of mails is send each time simplenews_mail_send() called
  if ($messages = simplenews_mail_cache_get(SIMPLENEWS_CACHE_PENDING, variable_get('simplenews_throttle', 20))) {

    // The id of succesfully sent messages are stored.
    // At completion these messages are removed from the mail cache table.
    $mail_sent = array();

    foreach($messages as $key => $message) {
      $counter++;
      if (variable_get('simplenews_debug', FALSE)) {
        watchdog('simplenews', 'Outgoing email. Message type: %type<br />Subject: %subject<br />Recipient: %to', array('%type' => $key, '%to' => $message['to'], '%subject' => $message['subject']), WATCHDOG_DEBUG);
      }

      if (drupal_mail_send($message)) {
        $mail_sent[] = $key;
      }
      else {
        watchdog('error', 'Error sending newsletter to %recipient.', array('%recipient' => $message['to']), WATCHDOG_ERROR);
      }
    }

    // All succesfully sent messages are removed from the mail cache.
    simplenews_mail_cache_clear($mail_sent);
  }
}

/**
 * Store mail message in mail cache table.
 *
 * @param array $message Mail message array
 */
function simplenews_mail_cache_set($message) {
  $tid = $message['params']['context']['node']->simplenews['tid'];
  $nid = $message['params']['context']['node']->nid;
  unset($message['params']);
  db_query("INSERT INTO {simplenews_mail_cache} (nid, tid, subject, mail, status, timestamp, message)
            VALUES (%d, %d, '%s', '%s', %d, %d, %b)", $nid, $tid, $message['subject'], $message['to'], SIMPLENEWS_CACHE_PENDING, time(), serialize($message));
}

/**
 * Retreive data from mail cache table
 *
 * @param string $status Status of data to be retreived (0 = hold, 1 = pending, 2 = send)
 * @param integer $limit the maximum number of mails loaded from the cache
 *
 * @return array Mail message array
 */
function simplenews_mail_cache_get($status, $limit = 999999) {
  $result = db_query("SELECT c.mcid, c.message FROM {simplenews_mail_cache} c WHERE c.status = %d ORDER BY c.timestamp ASC LIMIT 0, %d", $status, $limit);
  while ($data = db_fetch_object($result)) {
    $messages[$data->mcid] = unserialize($data->message);
  }
  return $messages;
}

/**
 * Count data in mail cache table.
 *
 * @param integer $nid newsletter node id
 * @param string $status email send status
 *
 * @return array Mail message array
 */
function simplenews_mail_cache_count($nid, $status = SIMPLENEWS_CACHE_PENDING) {
  return db_result(db_query("SELECT COUNT(*) FROM {simplenews_mail_cache} c WHERE c.nid = %d AND c.status = %d", $nid, $status));
}

/**
 * Update status of mail data in cache table.
 *
 * Time stamp is set to current time.
 *
 * @param array $array Mail cache id of record to be updated
 * @param string $status New status (0 = hold, 1 = pending, 2 = send)
 */
function simplenews_mail_cache_update($array, $status) {
  db_query("UPDATE {simplenews_mail_cache} SET status = %d, timestamp = %d WHERE mcid IN (%s)", $status, time(), $implode(',', $array));
}

/**
 * Remove records from mail cache table.
 *
 * @param array $array Mail cache ids of records to be deleted
 */
function simplenews_mail_cache_clear($array) {
  $result = db_query("DELETE FROM {simplenews_mail_cache} WHERE mcid IN (%s)", implode(',', $array));
}

/**
 * Build formatted from-name and e-mail for a mail object.
 *
 * Each newsletter (serie; tid) can have a different from address.
 * The from name and address depend on the newsletter term tid which is included in the $node object
 *
 * @param object $node Node object of a simplenews newsletter
 *
 * @return array [address] = from address; [formatted] = formatted from name and address
 */
function _simplenews_set_from($node = NULL) {
  $address_default = variable_get('site_mail', ini_get('sendmail_from'));
  $name_default = variable_get('site_name', 'Drupal');

  if (isset($node->simplenews['tid'])) {
    $address = variable_get('simplenews_from_address_'. $node->simplenews['tid'], $address_default);
    $name = variable_get('simplenews_from_name_'. $node->simplenews['tid'], $name_default);
  }
  else {
    $address = variable_get('simplenews_from_address', $address_default);
    $name = variable_get('simplenews_from_name', $name_default);
  }

  return array(
    'address' => $address,
    'formatted' => '"'. mime_header_encode(addslashes(check_plain($name))) .'" <'. $address .'>',
  );
}

/**
 * Build header array with priority and receipt confirmation settings.
 *
 * @param $node: node object
 * @param $from: from e-mail address
 *
 * @return Header array with priority and receipt confirmation info
 */
function _simplenews_headers($node, $from) {
  $headers = array();

  // If receipt is requested, add headers.
  if ($node->simplenews['receipt']) {
    $headers['Disposition-Notification-To'] = $from;
    $headers['X-Confirm-Reading-To'] = $from;
  }

  // Add priority if set.
  switch ($node->simplenews['priority']) {
    case SIMPLENEWS_PRIORITY_HIGHEST:
      $headers['Priority'] = 'High';
      $headers['X-Priority'] = '1';
      $headers['X-MSMail-Priority'] = 'Highest';
      break;
    case SIMPLENEWS_PRIORITY_HIGH:
      $headers['Priority'] = 'urgent';
      $headers['X-Priority'] = '2';
      $headers['X-MSMail-Priority'] = 'High';
      break;
    case SIMPLENEWS_PRIORITY_NORMAL:
      $headers['Priority'] = 'normal';
      $headers['X-Priority'] = '3';
      $headers['X-MSMail-Priority'] = 'Normal';
      break;
    case SIMPLENEWS_PRIORITY_LOW:
      $headers['Priority'] = 'non-urgent';
      $headers['X-Priority'] = '4';
      $headers['X-MSMail-Priority'] = 'Low';
      break;
    case SIMPLENEWS_PRIORITY_LOWEST:
      $headers['Priority'] = 'non-urgent';
      $headers['X-Priority'] = '5';
      $headers['X-MSMail-Priority'] = 'Lowest';
      break;
  }

  // Add general headers
  $headers['Precedence'] = 'bulk';

  return $headers;
}

/**
 * HTML to text conversion for HTML and special characters.
 * 
 * Converts some special HTMLcharacters in addition to drupal_html_to_text()
 *
 * @param string $text Source text with HTML and special characters
 *
 * @return string Target text with HTML and special characters replaced
 */
function simplenews_html_to_text($text) {
  // Remove in-page links
  $pattern = '@<a[^>]+?href="#[^"]*"[^>]*?>(.+?)</a>@i';
  $text = preg_replace($pattern, '$1', $text);

  // Replace some special characters before performing the drupal standard conversion
  $preg = _simplenews_html_replace();
  $text = preg_replace(array_keys($preg), array_values($preg), $text); 
  
  // Perform standard drupal html to text conversion
  return drupal_html_to_text($text);
}

/**
 *  List of preg* regular expression patterns to search for and replace with
 */
function _simplenews_html_replace() {
    return array(
        '/&quot;/i'  => '"',
        '/&gt;/i'    => '>',
        '/&lt;/i'    => '<',
        '/&amp;/i'   => '&',
        '/&copy;/i'  => '(c)',
        '/&trade;/i' => '(tm)',
        '/&#8220;/'  => '"',
        '/&#8221;/'  => '"',
        '/&#8211;/'  => '-',
        '/&#8217;/'  => "'",
        '/&#38;/'    => '&',
        '/&#169;/'   => '(c)',
        '/&#8482;/'  => '(tm)',
        '/&#151;/'   => '--',
        '/&#147;/'   => '"',
        '/&#148;/'   => '"',
        '/&#149;/'   => '*',
        '/&reg;/i'   => '(R)',
        '/&bull;/i'  => '*',
        '/&euro;/i'  => 'Euro ',
    );
}

/**
 * Replace tokens in node body/teaser with user specific variables.
 */
function simplenews_replace_vars($node, $teaser = TRUE) {
  global $user;
  $variables = user_mail_tokens($user, $user->language);
  $node->body = strtr($node->body, $variables);
  if ($teaser) {
    $node->teaser = strtr($node->teaser, $variables);
  }
  return $node;
}

/**
 * Create a 32 character identifier.
 */
function simplenews_private_key() {
  $key = variable_get('simplenews_private_key', FALSE);
  if (!$key) {
    //  This will create a 32 character identifier (a 128 bit hex number) that is extremely difficult to predict
    $key = md5(uniqid(rand()));
    variable_set('simplenews_private_key', $key);
  }
  return $key;
}

/**
 * Implementation of hook_help.
 */
function simplenews_help($path, $arg) {
  switch ($path) {
    case 'admin/help#simplenews':
      $help  = "<p>". t('Simplenews sends html or plain text newsletters to the mailing list. Subscription and unsubscription are managed through a block, a form or by the newsletter administrator.') ."<br />\n";
      $help .=        t('Individual newsletters are grouped by a newsletter taxonomy term. Newsletters can have a block with the ability of (un)subscription, listing of recent newsletters and an associated rss-feed.') ."<br />\n";
      $help .=        t('Sending of large mailings can be managed by cron.') ."</p>\n";
      $help .= "<p>". t('For more information please read the configuration and customization handbook <a href="@handbook">Simplenews page</a>.', array('@handbook','http://drupal.org/node/197057')) ."</p>\n";
      return $help;
    case 'node/add/simplenews':
      $help = "<p>". t('Add this newsletter issue to a newsletter by selecting a newsletter from the select list.') ."</p>\n";
      $help .= "<p>". t('Send a newsletter or a test newsletter by selecting the appropriate radio button and submitting the node.') ."</p>\n";
      if (!module_exists('mimemail')) {
        $help .= "<p>". t('Install Mime Mail module to send HTML emails. Mime Mail is also used to send emails with attachments, both plain text and HTML emails.') ."</p>\n";
      }
      return $help;
    case 'admin/content/newsletters/settings':
      $help = '<p>'. t('Newsletter specific settings can be found at the <a href="@page">Newsletters settings page</a>.', array('@page' => url('admin/content/newsletters/types'))) ."</p>\n";
      return $help;
  }
}

/**
 * Generate the hash key used for subscribe/unsubscribe link.
 */
function _simplenews_generate_hash($mail, $snid, $tid) {
  return drupal_substr(md5($mail . simplenews_private_key()), 0, 10) . $snid .'t'. $tid;
}

/**
 * Determine possible mail format options.
 *
 * The mime_mail module must be installed to send HTML mails.
 */
function _simplenews_format_options() {
  $options = array('plain' => t('plain'));
  if (module_exists('mimemail')) {
    $options['html'] = t('html');
  }
  return $options;
}

/**
 * Implementation of hook_theme.
 */
function simplenews_theme() {
  return array(
    'simplenews_block' => array(
      'template' => 'simplenews-block',
      'arguments' => array('tid' => NULL),
    ),
    'simplenews_status' => array(
      'template' => 'simplenews-status',
      'file' => 'simplenews.admin.inc',
      'arguments' => array('status' => NULL, 'source' => NULL),
    ),
    'simplenews_newsletter' => array(
      'arguments' => array('node' => NULL, 'tid' => NULL),
    ),
    'simplenews_newsletter_subject' => array(
      'arguments' => array('name' => NULL, 'title' => NULL, 'langcode' => NULL),
    ),
    'simplenews_newsletter_body' => array(
      'arguments' => array('body' => NULL, 'title' => NULL, 'langcode' => NULL),
    ),
    'simplenews_newsletter_footer' => array(
      'arguments' => array('format' => NULL, 'hash' => NULL, 'test' => NULL, 'langcode' => NULL),
    ),
    'simplenews_newsletter_confirmation_subject' => array(
      'arguments' => array('newsletter' => NULL, 'site_name' => NULL, 'langcode' => NULL),
    ),
    'simplenews_newsletter_confirmation_body' => array(
      'arguments' => array('email' => NULL, 'newsletter' => NULL, 'op' => NULL, 'hash' => NULL, 'langcode' => NULL)
    ),
    'simplenews_newsletter_confirmation' => array(
      'arguments' => array('email' => NULL, 'newsletter' => NULL, 'snid' => NULL, 'op' => NULL, 'hash' => NULL),
    ),
    'simplenews_subscription_list' => array(
      'file' => 'simplenews.admin.inc',
      'arguments' => array('form' => NULL),
    ),
  );
}

/**
 * Process variables to format the simplenews block.
 * 
 * Collect data and apply access restrictions.
 *
 * $variables contains:
 * - $tid
 *
 * @see simplenews-block.tpl.php
 * @see theme_simplenews-block()
 */
function template_preprocess_simplenews_block(&$variables) {
  global $user;
  $tid = $variables['tid'];

  // Block content variables
  $variables['message'] = check_plain(variable_get('simplenews_block_m_'. $tid, t('Stay informed on our latest news!')));
  if (user_access('subscribe to newsletters')) {
    $variables['form'] = drupal_get_form('simplenews_block_form', $tid);
    $variables['subscription_link'] = l(t('Manage my subscriptions'), 'newsletter/subscriptions');
  }
  if (user_access('view links in block') || user_access('administer newsletters')) {
    $variables['newsletter_link'] = l(t('Previous issues'), 'taxonomy/term/'. $tid);
    $recent = simplenews_recent_newsletters($tid, variable_get('simplenews_block_i_'. $tid, 5));
    $variables['issue_list'] = theme('item_list', $recent, t('Previous issues'), 'ul');
    $term = taxonomy_get_term($tid);
    $variables['rssfeed'] = theme('feed_icon', url('taxonomy/term/'. $tid .'/0/feed'), t('@newsletter feed', array('@newsletter' => $term->name)));
  }

  // Block content control variables
  $variables['use_message'] = variable_get('simplenews_block_m_status_'. $tid, 1);
  $variables['use_form'] = variable_get('simplenews_block_f_'. $tid, 1);
  $variables['use_issue_link'] = variable_get('simplenews_block_l_'. $tid, 1);
  $variables['use_issue_list'] = variable_get('simplenews_block_i_status_'. $tid, 0);
  $variables['use_rss'] = variable_get('simplenews_block_r_'. $tid, 1);

  // Additional variables
  $variables['subscribed'] = (simplenews_user_is_subscribed($user->mail, $tid) == TRUE);
  $variables['user'] = !empty($user->uid);
}

/**
 * Theme the newsletter message subject and body.
 */
function theme_simplenews_newsletter($node, $tid) {
  $term = taxonomy_get_term($tid);
  $name = $term->name ? $term->name : t('Unassigned newsletter');
  $node->subject = '['. $name .'] '. $node->title;
  $node->body = '<h2>'. $node->title ."</h2>\n". $node->body;
  return $node;
}

/**
 * Theme the newsletter e-mail subject.
 */
function theme_simplenews_newsletter_subject($name, $title, $langcode) {
  return  '['. $name .'] '. $title;
}

/**
 * Theme the newsletter message body.
 */
function theme_simplenews_newsletter_body($body, $title, $langcode) {
  $output = '<h2>'. $title ."</h2>\n";
  $output .= $body;
  return $output;
}

/**
 * Theme the newsletter message footer.
 */
function theme_simplenews_newsletter_footer($format, $hash, $test = FALSE, $langcode) {
  if ($format == 'html') {
    $output = '<p>-- <br />'. l(t('Click here to unsubscribe from this newsletter'), 'newsletter/confirm/remove/'. $hash, array('html' => TRUE), $langcode) .'</p>';
  }
  else {
    $output = "\n\n-- \n". t('Unsubscribe from this newsletter: !url', array('!url' => url('newsletter/confirm/remove/'. $hash, array('absolute' => TRUE))), $langcode);
  }

  if ($test) {
    $output .= "\n- - - ". t('This is a test version of the newsletter. The above unsubscribe link does not work!', array(), $langcode) .' - - -';
  }
  return $output;
}

function theme_simplenews_newsletter_confirmation_subject($newsletter, $site_name, $langcode) {
  return t('Confirmation for @newsletter from @site', array('@newsletter' => $newsletter->name, '@site' => $site_name), $langcode);
}

/**
 * Construct the themable newsletter confirmation email.
 */
function theme_simplenews_newsletter_confirmation_body($email, $newsletter, $op, $hash, $langcode) {
  $body[] = t('This is a subscription status confirmation notice for the @newsletter.', array('@newsletter' => $newsletter->name), $langcode);
  $body[] = "\n\n";

  $user_is_subscribed = simplenews_user_is_subscribed($email, $newsletter->tid);
  switch ($op) {
    case 'subscribe':
      if ($user_is_subscribed) {
        $body[] = t('We have received a request for subscription of your e-mail address, @mail, to the @newsletter from @site (!url). However, you are already subscribed to this newsletter. If you want to unsubscribe, you can visit our website by using the link at the bottom of this e-mail.', array('@mail' => $email, '@newsletter' => $newsletter->name, '@site' => $mail->from_name, '!url' => url('', array('absolute' => TRUE))), $langcode);
        $body[] = "\n\n-- \n". t('Visit our site: !url', array('!url' => url('', array('absolute' => TRUE))), $langcode);
      }
      else {
        $body[] = t('We have received a request for subscription of your e-mail address, @mail, to the @newsletter from @site (!url). To confirm that you want to be added to this mailing list, simply visit the confirmation link at the bottom of this e-mail.', array('@mail' => $email, '@newsletter' => $newsletter->name, '@site' => $mail->from_name, '!url' => url('', array('absolute' => TRUE))), $langcode);
        $body[] = "\n\n". t('If you do not wish to be subscribed to this list, please disregard this message.', array(), $langcode);
        $body[]  = "\n\n-- \n". t('Subscribe link: !url', array('!url' => url('newsletter/confirm/add/'. $hash, array('absolute' => TRUE))), $langcode);
      }
      break;
    case 'unsubscribe':
      if ($user_is_subscribed) {
        $body[] = t('We have received a request for the removal of your e-mail address, @mail, from the @newsletter from @site (!url). If you want to unsubscribe, simply visit the confirmation link at the bottom of this e-mail.', array('@mail' => $email, '@newsletter' => $newsletter->name, '@site' => $mail->from_name, '!url' => url('', array('absolute' => TRUE))), $langcode);
        $body[] = "\n\n". t('If you did not make this request, please disregard this message.', array(), $langcode);
        $body[]  = "\n\n-- \n". t('Unsubscribe link: !url', array('!url' => url('newsletter/confirm/remove/'. $hash, array('absolute' => TRUE))), $langcode);
      }
      else {
        $body[] = t('We have received a request for the removal of your e-mail address, @mail, from the @newsletter from @site (!url). However, you were not subscribed to this newsletter. If you want to subscribe, you can visit our website by using the link at the bottom of this e-mail.', array('@mail' => $email, '@newsletter' => $newsletter->name, '@site' => $mail->from_name, '!url' => url('', array('absolute' => TRUE))), $langcode);
        $body[] = "\n\n". t('If you do not wish to be subscribed to this list, please disregard this message.', array(), $langcode);
        $body[] = "\n\n-- \n". t('Visit our site: !url', array('!url' => url('', array('absolute' => TRUE))), $langcode);
      }
      break;
  }

   return $body;
}

/**
 * Construct the themable newsletter confirmation email.
 */
function theme_simplenews_newsletter_confirmation($email, $newsletter, $snid, $op, $hash) {
  $mail = new stdClass();

  $mail->simplenews['s_format'] = 'plain';
  $mail->simplenews['priority'] = 'none';

  $mail->simplenews['to'] = $email;
  $mail->simplenews['subject'] = t('Confirmation for @newsletter from @site', array('@newsletter' => $newsletter->name, '@site' => $mail->from_name));
  $mail->body = t('This is a subscription status confirmation notice for the @newsletter.', array('@newsletter' => $newsletter->name));
  $mail->body .= "\n\n";

  $user_is_subscribed = simplenews_user_is_subscribed($email, $newsletter->tid);
  switch ($op) {
    case 'subscribe':
      if ($user_is_subscribed) {
        $mail->body .= t('We have received a request for subscription of your e-mail address, @mail, to the @newsletter from @site (!url). However, you are already subscribed to this newsletter. If you want to unsubscribe, you can visit our website by using the link at the bottom of this e-mail.', array('@mail' => $email, '@newsletter' => $newsletter->name, '@site' => $mail->from_name, '!url' => url('', array('absolute' => TRUE))));
      }
      else {
        $mail->body .= t('We have received a request for subscription of your e-mail address, @mail, to the @newsletter from @site (!url). To confirm that you want to be added to this mailing list, simply visit the confirmation link at the bottom of this e-mail.', array('@mail' => $email, '@newsletter' => $newsletter->name, '@site' => $mail->from_name, '!url' => url('', array('absolute' => TRUE))));
        $mail->body .= "\n\n". t('If you do not wish to be subscribed to this list, please disregard this message.');
        $footer = "\n\n-- \n". t('Subscribe link: !url', array('!url' => url('newsletter/confirm/add/'. $hash, array('absolute' => TRUE))));
      }
      break;
    case 'unsubscribe':
      if ($user_is_subscribed) {
        $mail->body .= t('We have received a request for the removal of your e-mail address, @mail, from the @newsletter from @site (!url). If you want to unsubscribe, simply visit the confirmation link at the bottom of this e-mail.', array('@mail' => $email, '@newsletter' => $newsletter->name, '@site' => $mail->from_name, '!url' => url('', array('absolute' => TRUE))));
        $mail->body .= "\n\n". t('If you did not make this request, please disregard this message.');
        $footer = "\n\n-- \n". t('Unsubscribe link: !url', array('!url' => url('newsletter/confirm/remove/'. $hash, array('absolute' => TRUE))));
      }
      else {
        $mail->body .= t('We have received a request for the removal of your e-mail address, @mail, from the @newsletter from @site (!url). However, you were not subscribed to this newsletter. If you want to subscribe, you can visit our website by using the link at the bottom of this e-mail.', array('@mail' => $email, '@newsletter' => $newsletter->name, '@site' => $mail->from_name, '!url' => url('', array('absolute' => TRUE))));
        $mail->body .= "\n\n". t('If you do not wish to be subscribed to this list, please disregard this message.');
      }
      break;
  }

  if (!isset($footer)) {
    $footer = "\n\n-- \n". t('Visit our site: !url', array('!url' => url('', array('absolute' => TRUE))));
  }

  $mail->body .= $footer;
  return $mail;
}