<?php
// $Id: og_forum.module,v 1.11.2.16 2007-06-30 00:32:26 rconstantine Exp $

/**
 * @file
 * Creates a forum per organic group and restricts viewing forum nodes by group membership.
 * 
 * TODO: either remove og_forums from site-wide forum admin page (so they aren't screwed up)
 * or add og_forum functionality to that form. Ideas: if admin wants to create a container or
 * forum for an OG, check the parent drop down box, and if that tid is associated with an OG,
 * call the og_forum functions instead of the forum functions. This would require(?) a patch
 * to the core forum module. Or can I manipulate #submit and use other similar tricks?
 * 
 * TODO: fix breadcrumbs 
 * 
 */

/**
 * Implementation of hook_help().
 */
function og_forum_help($section) {
  switch ($section) {
    case 'admin/modules#description':
      return t('Ties forums to organic groups.');
  }
}

/**
 * Implementation of hook_menu().
 */
function og_forum_menu($may_cache) {
  $items = array();
  $items[] = array(
    'path' => 'og_forum',
    'callback' => 'og_forum_page',
    'type' => MENU_CALLBACK,
    'access' => user_access('access content'),
  );
  $items[] = array(
    'path' => 'forum',
    'callback' => 'og_forum_page',
    'type' => MENU_CALLBACK,
    'access' => user_access('access content'),
  );
  $items[] = array(
    'path' => 'admin/og/og_forum',
    'title' => t('Organic Groups Forums'),
    'description' => t('Configure Organic Groups Forums'),
    'callback' => 'drupal_get_form',
    'callback arguments' => array('og_forum_admin_settings'),
    'access' => user_access('administer site configuration'),
  );
  
  // we expect the group nid as 1st argument
  if (is_numeric(arg(2))) {
    // load forum's group
    $group = node_load(arg(2));
    if ($group) {
      if (og_forum_is_admin($group)) {
        $items[] = array(
          'title' => t('Manage group\'s forum'),
          'path' => 'og_forum/manage',
          'callback' => 'og_forum_manage',
          'callback arguments' => array($group),
          'type' => MENU_CALLBACK,
          'access' => user_access('access content'),
        );
      }
    }
  }
  elseif (is_numeric(arg(3)) && is_numeric(arg(4))) {
    if (arg(2) == 'add') {
      $items[] = array(
      'path' => 'og_forum/manage/add',
        'title' => t('Add forum'),
        'callback' => 'og_forum_form_main',
        'callback arguments' => array('add', array('group_id' => arg(3), 'parent' => arg(4))),
        'access' => user_access('access content'),
        'type' => MENU_CALLBACK
      );
    }
    elseif (arg(2) == 'edit') {
      $term = taxonomy_get_term(arg(4));
      $parents = taxonomy_get_parents($term->tid);
      $parent = array_pop($parents);
      $term->parent = $parent->tid;
      $term->group_id = arg(3);
      $items[] = array(
      'path' => 'og_forum/manage/edit',
        'title' => t('Edit forum'),
        'callback' => 'og_forum_form_main',
        'callback arguments' => array('edit', (array)$term),
        'access' => user_access('access content'),
        'type' => MENU_CALLBACK
      );
    }
  }
  return $items;
}

/**
 * Menu callback; allows us to set group context prior to
 * loading a forum
 */
function og_forum_page($tid = 0) {
  global $user;
  if ($tid != 0) {
    og_forum_set_og_group_context_from_tid($tid);
    $gid = og_forum_gid_from_tid($tid);
    if ($gid) {
      if (!array_key_exists($gid, $user->og_groups) && ($user->uid != 1)) {
        return drupal_access_denied();
      }
    }
  }
  elseif (is_numeric(og_get_group_context())) {
    $tid = og_get_group_context();
  }
  //The rest is copied from forum_page with a modified theme call
  if (module_exists('taxonomy') && module_exists('comment')) {
    $forum_per_page = variable_get('forum_per_page', 25);
    $sortby = variable_get('forum_order', 1);
    $forums = forum_get_forums($tid);
    $parents = taxonomy_get_parents_all($tid);
    if ($tid && !in_array($tid, variable_get('forum_containers', array()))) {
      $topics = forum_get_topics($tid, $sortby, $forum_per_page);
    }
    return theme('og_forum_display', $forums, $topics, $parents, $tid, $sortby, $forum_per_page);
  }
  else {
    drupal_set_message(t('The forum module requires both the taxonomy module and the comment module to be enabled and configured.'), 'error');
    return ' ';
  }  
}

/**
 * Format the forum body.
 * 
 * Copied from forum module. Slightly modified to produce correct links and eliminate 'add new topic' links in containers.
 *
 * @ingroup themeable
 */
function theme_og_forum_display($forums, $topics, $parents, $tid, $sortby, $forum_per_page) {
  global $user;
  // forum list, topics list, topic browser and 'add new topic' link
  $vocabulary = taxonomy_get_vocabulary(variable_get('forum_nav_vocabulary', ''));
  $title = $vocabulary->name;
  // Breadcrumb navigation:
  $breadcrumb = array();
  if ($parents) {
    $parents = array_reverse($parents);
    foreach ($parents as $p) {
      if ($p->tid == $tid) {
        $title = $p->name;
      }
      else {
        $breadcrumb[] = array('path' => 'og_forum/'. $p->tid, 'title' => $p->name);
      }
    }
  }
  drupal_set_title(check_plain($title));
  $breadcrumb[] = array('path' => $_GET['q']);
  menu_set_location($breadcrumb);
  if (count($forums) || count($parents)) {
    $output  = '<div id="forum">';
    $output .= '<ul>';
    if (user_access('create forum topics') && !in_array($tid, variable_get('forum_containers', array())) && ($tid != 0)) {
      og_forum_set_og_group_context_from_tid($tid);
      /*$gid = og_forum_gid_from_tid($tid);
      //group forum link with group selected
      if(!empty($gid)){
        $output .= '<li>'. l(t('Post new forum topic.'), "node/add/forum/$tid", array() , "gids[]=$gid") .'</li>';
      }
      else {//normal forum*/
        $output .= '<li>'. l(t('Post new forum topic.'), "node/add/forum/$tid") .'</li>';
      //}
    }
    else if (user_access('create forum topics')) {
      $output .= '<li>'. t('Select a forum below.') .'</li>';
    }
    else if ($user->uid) {
      $output .= '<li>'. t('You are not allowed to post a new forum topic.') .'</li>';
    }
    else {
      $output .= '<li>'. t('<a href="@login">Login</a> to post a new forum topic.', array('@login' => url('user/login', drupal_get_destination()))) .'</li>';
    }
    $output .= '</ul>';
//drupal_set_message('<pre>Forums: ' .print_r($forums, TRUE). '</pre>');
    $output .= theme('og_forum_list', $forums, $parents, $tid);
    if ($tid && !in_array($tid, variable_get('forum_containers', array()))) {
      $output .= theme('og_forum_topic_list', $tid, $topics, $sortby, $forum_per_page);
      drupal_add_feed(url('taxonomy/term/'. $tid .'/0/feed'), 'RSS - '. $title);
    }
    $output .= '</div>';
  }
  else {
    drupal_set_title(t('No forums defined'));
    $output = '';
  }
  return $output;
}

/**
 * Format the forum listing.
 * 
 * Copied from forum module. Slightly modified to produce correct links.
 *
 * @ingroup themeable
 */
function theme_og_forum_list($forums, $parents, $tid) {
  global $user;
  if ($forums) {
    $header = array(t('Forum'), t('Topics'), t('Posts'), t('Last post'));
    foreach ($forums as $forum) {
      if ($forum->container) {
        $description  = '<div style="margin-left: '. ($forum->depth * 30) ."px;\">\n";
        $description .= ' <div class="name">'. l($forum->name, "og_forum/$forum->tid") ."</div>\n";
        if ($forum->description) {
          $description .= ' <div class="description">'. filter_xss_admin($forum->description) ."</div>\n";
        }
        $description .= "</div>\n";
        $rows[] = array(array('data' => $description, 'class' => 'container', 'colspan' => '4'));
      }
      else {
        $new_topics = _forum_topics_unread($forum->tid, $user->uid);
        $forum->old_topics = $forum->num_topics - $new_topics;
        if (!$user->uid) {
          $new_topics = 0;
        }
        $description  = '<div style="margin-left: '. ($forum->depth * 30) ."px;\">\n";
        $description .= ' <div class="name">'. l($forum->name, "og_forum/$forum->tid") ."</div>\n";
        if ($forum->description) {
          $description .= ' <div class="description">'. filter_xss_admin($forum->description) ."</div>\n";
        }
        $description .= "</div>\n";
        $rows[] = array(
          array('data' => $description, 'class' => 'forum'),
          array('data' => $forum->num_topics . ($new_topics ? '<br />'. l(format_plural($new_topics, '1 new', '@count new'), "og_forum/$forum->tid", NULL, NULL, 'new') : ''), 'class' => 'topics'),
          array('data' => $forum->num_posts, 'class' => 'posts'),
          array('data' => _forum_format($forum->last_post), 'class' => 'last-reply'));
      }
    }
    return theme('table', $header, $rows);
  }
}

/**
 * Format the topic listing.
 * 
 * Copied from forum module. Slightly modified to produce correct links.
 *
 * @ingroup themeable
 */
function theme_og_forum_topic_list($tid, $topics, $sortby, $forum_per_page) {
  global $forum_topic_list_header;
  if ($topics) {
    foreach ($topics as $topic) {
      // folder is new if topic is new or there are new comments since last visit
      if ($topic->tid != $tid) {
        $rows[] = array(
          array('data' => theme('forum_icon', $topic->new, $topic->num_comments, $topic->comment_mode, $topic->sticky), 'class' => 'icon'),
          array('data' => check_plain($topic->title), 'class' => 'title'),
          array('data' => l(t('This topic has been moved'), "og_forum/$topic->tid"), 'colspan' => '3')
        );
      }
      else {
        $rows[] = array(
          array('data' => theme('forum_icon', $topic->new, $topic->num_comments, $topic->comment_mode, $topic->sticky), 'class' => 'icon'),
          array('data' => l($topic->title, "node/$topic->nid"), 'class' => 'topic'),
          array('data' => $topic->num_comments . ($topic->new_replies ? '<br />'. l(format_plural($topic->new_replies, '1 new', '@count new'), "node/$topic->nid", NULL, NULL, 'new') : ''), 'class' => 'replies'),
          array('data' => _forum_format($topic), 'class' => 'created'),
          array('data' => _forum_format(isset($topic->last_reply) ? $topic->last_reply : NULL), 'class' => 'last-reply')
        );
      }
    }
  }
  $output = theme('table', $forum_topic_list_header, $rows);
  $output .= theme('pager', NULL, $forum_per_page, 0);
  return $output;
}

/**
 * Implementation of hook_settings().
 */
function og_forum_admin_settings() {
  $form['#submit']['og_forum_settings_submit'] = array(); // custom submit handler
  $form['#submit']['system_settings_form_submit'] = array(); // form.inc never calls the $callback if a submit handler is defined
  $form['update'] = array(
    '#type' => 'fieldset',
    '#title' => t('Retroactively update old groups'),
    '#description' => t('Pressing this button will create forums for any groups that do not already have them.'),
    '#collapsible' => TRUE,
  );
  $form['update']['button'] = array(
    '#type' => 'submit',
    '#value' => t('Update old groups'),
  );
  return system_settings_form($form);
}

/**
 * Custom submit handler for group update
 */
function og_forum_settings_submit($form_id, $form_values) {
  if ($form_values['op'] == t('Update old groups')) {
    og_forum_retroactively_apply();
  }
}

/**
 * using the tid, set the group context
 */
function og_forum_set_og_group_context_from_tid($tid=0) {
  $sql = "SELECT nid FROM {og_term} WHERE tid = %d";
  if ($gid = db_result(db_query($sql, $tid))) {
  $group_node = node_load($gid);
  og_set_group_context($group_node);
  }
}

/**
 * using the tid, get the group id
 */
function og_forum_gid_from_tid($tid=0) {
  $sql = "SELECT nid FROM {og_term} WHERE tid = %d";
  $gid = db_result(db_query($sql, $tid));
  return $gid;
}

/**
 * Implementation of hook_db_rewrite_sql().
 *
 * Restricts forum viewing by organic group.
 * 
 * How this works:
 * First, each small part-
 * The forums in groups OTHER users belong to: SELECT ogt.tid FROM og_term ogt INNER JOIN og_uid ogu ON ogt.nid = ogu.nid AND ogu.uid != $user->uid;
 * The forums in groups USER belongs to: SELECT ogt.tid FROM og_term ogt INNER JOIN og_uid ogu ON ogt.nid = ogu.nid AND ogu.uid = $user->uid;
 * The forums in groups user belongs to, but is INACTIVE: SELECT ogt.tid FROM og_term ogt INNER JOIN og_uid ogu ON ogt.nid = ogu.nid AND ogu.uid = $user->uid WHERE ogu.is_active = 0;
 * 
 * Put the first two together-
 * The forums in groups the user DOES NOT belong to.
 * SELECT x.tid FROM (SELECT ogt.tid FROM og_term ogt INNER JOIN og_uid ogu ON ogt.nid = ogu.nid AND ogu.uid != $user->uid) x 
 * WHERE x.tid NOT IN (SELECT ogt.tid FROM og_term ogt INNER JOIN og_uid ogu ON ogt.nid = ogu.nid AND ogu.uid = $user->uid));
 * 
 * Put it all together and you can read it like this: WHERE t.tid NOT IN (The forums in groups the user DOES NOT belong to) 
 * AND t.tid NOT IN (The forums in groups user belongs to, but is INACTIVE)
 * 
 * This should show all forums for which the user is a group member as well as those forums in the site-wide forums.
 * TODO optionally allow users to view ALL forums in and out of subscribed groups unless marked PRIVATE by the group admin
 */
function og_forum_db_rewrite_sql($query, $primary_table = 'n', $primary_field = 'nid') {
  global $user;
  $restrict = FALSE;
  $restrict2 = FALSE;
  if ($primary_field == 'tid') {
    // Only do this on forum nodes
    if (((arg(0) == 'forum') || (arg(0) == 'og_forum') || (db_result(db_query('SELECT type FROM {node} WHERE nid = %d', arg(1))) == 'forum')) && ($user->uid != 1)) {
      $restrict = TRUE;
    }
    elseif ((arg(0) == 'node' && arg(1) == 'add' && arg(2) == 'forum' && arg(3)) && ($user->uid != 1)) {   
      $restrict = TRUE;
      $restrict2 = TRUE;
    }
    elseif ((arg(0) == 'node' && arg(1) == 'add' && arg(2) == 'forum') && ($user->uid != 1)) {
      $restrict = TRUE;
    }
    // If on a forum node, prevent display of all forums; only the ones for this organic group
    // The forum vocab should have a lower weight than any other vocabulary assigned to forum nodes.
    static $og_vocab = FALSE;
    if ($restrict) {
	//This query and the one below are what makes regular forums work side by side with og forums.
	//Esentially, instead of sequentially restricting our selection based on whether the forum is in an organic group,
	//we find which organic group forums we don't want to show and remove them from the site-wide forum list.
	//What remains are all regular forums, plus those the user is subscribed to in each group and which is_active is set to 1.  
      $return['where'] = 't.tid NOT IN (SELECT x.tid FROM (SELECT ogt.tid FROM {og_term} ogt INNER JOIN {og_uid} ogu ON ogt.nid = ogu.nid AND ogu.uid != ' .$user->uid. ') x
      WHERE x.tid NOT IN (SELECT ogt.tid FROM {og_term} ogt INNER JOIN {og_uid} ogu ON ogt.nid = ogu.nid AND ogu.uid = ' .$user->uid. ')) 
      AND t.tid NOT IN (SELECT ogt.tid FROM {og_term} ogt INNER JOIN {og_uid} ogu ON ogt.nid = ogu.nid AND ogu.uid = ' .$user->uid. ' WHERE ogu.is_active = 0)';
      if ($restrict2) {
      	$og_nid = og_forum_gid_from_tid(arg(3));
        if ($og_nid && !$og_vocab) {
          $og_vocab = TRUE;
          //Same as above, except without removing is_active == 0 forums since we are looking for a particular node.
	  //Need to put the join in here since we need to match ogt.nid
          $return['join'] = "LEFT JOIN {og_term} ogt ON $primary_table.tid = ogt.tid";
          $return['where'] = "t.tid NOT IN (SELECT x.tid FROM
	    (SELECT ogt.tid FROM {og_term} ogt INNER JOIN {og_uid} ogu ON ogt.nid = ogu.nid AND ogu.uid != ' .$user->uid. ') x
	    WHERE x.tid NOT IN (SELECT ogt.tid FROM {og_term} ogt INNER JOIN {og_uid} ogu ON ogt.nid = ogu.nid AND ogu.uid = ' .$user->uid. ')) 
	    AND ogt.nid = $og_nid";
        }
      }
      $return['distinct'] = TRUE;
      return $return;
    }
    else {
      $og_vocab = FALSE;
      return NULL;
    }
  }
}

/**
 * Implementation of hook_nodeapi().
 *
 * Automatically creates a forum container and forum each time an organic group is added.
 */
function og_forum_nodeapi($node, $op, $teaser = NULL, $page = NULL) {
  switch ($op) {
    case 'load':
      if ($node->type == 'forum' && $og_forum_nid = db_result(db_query('SELECT nid FROM {og_term} WHERE tid = %d', $node->tid))) {
        $node->og_forum_nid = $og_forum_nid;
      }
      break;
    case 'prepare':
      if (arg(0) == 'node' && arg(1) == 'add' && arg(2) == 'forum' && arg(3)) {
        if (!og_get_group_context()) {
          og_forum_set_og_group_context_from_tid(arg(3));
          //return FALSE;
        }
      }
      break;
    case 'insert':
      if (og_is_group_type($node->type)) {
        $edit = array('name' => $node->title, 'vid' => _forum_get_vid());
        $status = taxonomy_save_term($edit);
        $containers = variable_get('forum_containers', array());
        $containers[] = $edit['tid'];
        variable_set('forum_containers', $containers);
        db_query('INSERT INTO {og_term} (tid, nid) VALUES (%d, %d)', $edit['tid'], $node->nid);

        $edit['name'] = t('General discussion');
        $edit['parent'] = array($edit['tid']);
        unset($edit['tid']);
        $status = taxonomy_save_term($edit);
        //db_query('INSERT INTO {og_term} (tid, nid) VALUES (%d, %d)', $edit['tid'], $node->nid);
      }
      break;
    case 'delete':
      // Delete existing terms for this og
      if (og_is_group_type($node->type)) {
        $result = db_query('SELECT tid FROM {og_term} WHERE nid = %d', $node->nid);
        while ($term = db_fetch_object($result)) {
          taxonomy_del_term($term->tid);
        }
        db_query('DELETE FROM {og_term} WHERE nid = %d', $node->nid);
      }
      break;
    case 'view':
      // If we're viewing a forum post in a group forum, set that
      // group as the context.
      if ($page && $node->og_forum_nid) {
        og_set_group_context(node_load($node->og_forum_nid));
      }
      break;
  }
}

/**
 * Retrieve container for given group
 *
 * @param $group_id
 *   Organic group ID
 * @return
 *   Forum container's term ID
 */
function og_forum_get_forum_container($group_id) {
  // Grab most first term created for group; this will be the forum container
  return db_result(db_query_range('SELECT tid FROM {og_term} WHERE nid = %d ORDER BY tid ASC', $group_id, 0, 1));
}

/**
 * Check if a user is a group manager of the given group
 */
function og_forum_is_admin($group) {
  global $user;
  $result = db_query(og_list_users_sql(0), $group->nid);
  $cntall = db_num_rows($result);
  $cntpending = 0;
  while ($row = db_fetch_object($result)) {
    if ($user->uid == 1) return TRUE;
    if ($row->uid == $user->uid) {
      if ($row->is_admin > 0) return TRUE;
    }
  }
  return FALSE;
}

/**
 * Implementation of hook_og_create_links().
 */
function og_forum_og_create_links($group) {
  global $user;
  $links = array();
  // Get group's forum
  $forum  = og_forum_get_forum_container($group->nid);
  if ($forum) {
    $links[] = l(t('Group forums'), "og_forum/$forum", array('title' => t('View group forum discussions.')));
  // Add forum creation link for the group managers
    if (og_forum_is_admin($group)) {
      $links[] = l(t('Manage group forums'), 'og_forum/manage/' . $group->nid, array('title' => t('Let you create, edit, delete group\'s forums.')));
    }
  }
  return $links;
}

/**
 * Creates forums for all groups that don't have any yet.
 */
function og_forum_retroactively_apply() {
  $counter = 0;
  // Obtain list of all groups
  $result = db_query('SELECT og.nid, n.title, n.type FROM {og} og INNER JOIN {node} n on og.nid = n.nid');
  while ($group = db_fetch_object($result)) {
    // See if terms are found for this group
    if (!db_result(db_query('SELECT * FROM {og_term} ogt WHERE ogt.nid = %d', $group->nid))) {
      // If not, fake a nodeapi insert
      og_forum_nodeapi($group, 'insert');
      $counter++;
    }
  }
  drupal_set_message(t('%num groups had forums created', array('%num' => $counter)));
}

/**
 * Implementation of hook_form_alter().
 * 
 * TODO make this behavior optional - i.e. let the admin select whether to lock a user out of selecting a different forum and also cross-posting
 */
function og_forum_form_alter($form_id, &$form) {
  // Auto-select group's forum when adding/editing a forum topic
  if ($form_id == 'forum_node_form') {
    $group = og_get_group_context();
    if ($group->nid) {
      $vid =  _forum_get_vid();
      $term = arg(3);
      $form['taxonomy'][$vid]['#default_value'] = array($term);
      if (!user_access('administer forums')) {
        unset ($form['taxonomy'][$vid]['#default_value']);
        //unset ($form['taxonomy'][$vid]['#type']);
        $form['taxonomy']['#type'] = 'fieldset';
        $form['taxonomy']['#title'] = 'Forum context';//comment this line out to hide the drop down; i couldn't get [#type] = 'hidden' to work
        $form['taxonomy']['#collapsible'] = TRUE;
        $form['taxonomy']['#collapsed'] = TRUE;
        $form['taxonomy'][$vid]['#value'] = $term;
        $form['taxonomy'][$vid]['#description'] = 'When inside a group forum, changing this value has no effect.';
      }
    }
  }
}

/**
 * Let group managers manage their forums
 */
function og_forum_manage($group) {
  global $user;
  og_set_theme($group->nid);
  og_set_group_context($group);
  // set a nice breadcrumb
  _og_forum_manage_breadcrumb($group);
  $content = '<p>'. t('This page shows the forums associated with the %group group.', array('%group' => $group->title)) .'</p>';
  $og_terms = _og_forum_ogterms($group);
  $header = array(t('Name'), t('Operations'));
  $tree = taxonomy_get_tree(_forum_get_vid());
  if ($tree) {
    foreach ($tree as $term) {
      if (in_array($term->tid, $og_terms)) {
        if (in_array($term->tid, variable_get('forum_containers', array()))) {
          $rows[] = array(str_repeat('-', $term->depth). ' ' .check_plain($term->name), l(t('add forum'), "og_forum/manage/add/$group->nid/$term->tid"));
        }
        else {
          $rows[] = array(str_repeat('-', $term->depth). ' ' .check_plain($term->name), l(t('edit forum'), "og_forum/manage/edit/$group->nid/$term->tid"));
        }
      }
    }
  }
  return $content . theme('table', $header, $rows);
}

/**
 * Select the right form to display
 */
function og_forum_form_main($type, $edit = array()) {
  if ($_POST['op'] == t('Delete') || $_POST['confirm']) {
    return drupal_get_form('og_forum_confirm_delete', $edit['tid'], $group_id);
  }
  switch ($type) {
    case 'add':
      $group_id = $edit['group_id'];
      return drupal_get_form('og_forum_form_forum', $edit, $group_id, $edit['tid']);
      break;
    case 'edit':
      $group_id = $edit['group_id'];
      return drupal_get_form('og_forum_form_forum', $edit, $group_id);
      break;
  }
}

/**
 * Render forum creation form
 */
function og_forum_form_forum($edit, $group_id = 0, $tid = 0) {
  og_set_theme($gid);
  if (!$edit['tid']) {
    $tid = $edit['parent'];
  }
  _og_forum_manage_breadcrumb(node_load($group_id));
  $form['name'] = array('#type' => 'textfield',
    '#title' => t('Forum name'),
    '#default_value' => $edit['name'],
    '#maxlength' =>  64,
    '#description' => t('The forum name is used to identify related discussions.'),
    '#required' => TRUE,
  );
  $form['description'] = array('#type' => 'textarea',
    '#title' => t('Description'),
    '#default_value' => $edit['description'],
    '#description' => t('The forum description can give users more information about the discussion topics it contains.'),
  );
  if (arg(2) == 'add') {
    $form['parent'] = array(
      '#type' => 'hidden',
      '#value' => $tid,
    );
  }
  else {
    $form['parent'] = array(
      '#type' => 'hidden',
      '#value' => $edit['parent'],
    );
  }
  $form['group_id'] = array(
    '#type' => 'hidden',
    '#value' => $group_id,
  );
  $form['weight'] = array('#type' => 'weight',
    '#title' => t('Weight'),
    '#default_value' => $edit['weight'],
    '#description' => t('When listing forums, those with lighter (smaller) weights get listed before containers with heavier (larger) weights. Forums with equal weights are sorted alphabetically.'),
  );
  $form['vid'] = array('#type' => 'hidden', '#value' => _forum_get_vid());
  $form['submit' ] = array('#type' => 'submit', '#value' => t('Submit'));
  if ($edit['tid']) {
    $form['delete'] = array('#type' => 'submit', '#value' => t('Delete'));
    $form['tid'] = array('#type' => 'hidden', '#value' => $edit['tid']);
  }
  $form['#base'] = 'og_forum_form';
  return $form;
}

/**
  * Validate group id and term id values
  */
function og_forum_form_validate($form_id, $form_values) {
  global $user;
  $error = true;
  if (is_numeric($form_values['group_id'])) {
    $group = node_load($form_values['group_id']);
    // check that the user is the manager
    if ($group && og_forum_is_admin($group) && (in_array($form_values['parent'], _og_forum_ogterms($group)) || $form_values['tid'])) {
      $error = false;
    }
  }
  // stop insertion if we found invalid values
  if ($error) {
    form_set_error('name', t('Internal error processing your data. Please contact website administrators.'));
  }
}

/**
 * Store created/updated forum on the db
 */
function og_forum_form_submit($form_id, $form_values) {
  $container = false;
  $type = t('forum');
  $status = taxonomy_save_term($form_values);
  switch ($status) {
    case SAVED_NEW:
      if ($container) {
        $containers = variable_get('forum_containers', array());
        $containers[] = $form_values['tid'];
        variable_set('forum_containers', $containers);
      }
      drupal_set_message(t('Created new !type %term.', array('%term' => $form_values['name'], '!type' => $type)));
      break;
    case SAVED_UPDATED:
      drupal_set_message(t('The !type %term has been updated.', array('%term' => $form_values['name'], '!type' => $type)));
      break;
  }
  return 'og_forum/manage/' .$form_values['group_id'];
}

/**
 * hook_taxonomy implementation
 * 
 * This should replace og_forum's own management of terms which bypasses regular taxonomy. Using this function allows group
 * forums to be managed both from within the group and at the site-wide forum admin pages.
 *
 * @param string $op
 * @param string $type
 * @param array $obj
 */
function og_forum_taxonomy($op, $type, $obj) {
  switch ($op) {
    case 'insert':
    case 'update':
      if (isset($obj['parent'])) {
        $parent = (is_array ($obj['parent'])) ? $obj['parent'][0] : $obj['parent'];
        $result = db_result(db_query("SELECT nid FROM {og_term} WHERE tid = %d", $parent));
        if ($result) {
          if (!db_result(db_query('SELECT tid FROM {og_term} WHERE tid = %d', $obj['tid']))) {
            db_query('INSERT INTO {og_term} (tid, nid) VALUES (%d, %d)', $obj['tid'], $result);
          }
        }
      }
      break;
    case 'delete':
      if (isset($obj['tid'])) {
        db_query("DELETE FROM {og_term} WHERE tid = %d", $obj['tid']);		
      }
      break;
  }	
}

/**
 * Returns a confirmation page for deleting a forum taxonomy term.
 *
 * @param $tid ID of the term to be deleted
 */
function og_forum_confirm_delete($tid, $group_id) {
  $term = taxonomy_get_term($tid);
  $form['tid'] = array('#type' => 'value', '#value' => $tid);
  $form['name'] = array('#type' => 'value', '#value' => $term->name);
  $form['group_id'] = array('#type' => 'value', '#value' => $group_id);
  $return_address = 'og_forum/manage/' .arg(3);
  $form = confirm_form($form, t('Are you sure you want to delete the forum %name?', array('%name' => $term->name)), $return_address, t('Deleting a forum or container will delete all sub-forums and associated posts as well. This action cannot be undone.'), t('Delete'), t('Cancel'));
  return $form;
}

/**
 * Implementation of forms api _submit call. Deletes a forum after confirmation.
 */
function og_forum_confirm_delete_submit($form_id, $form_values) {
  taxonomy_del_term($form_values['tid']);
  $group_id = og_forum_gid_from_tid($form_values['tid']);
  drupal_set_message(t('The forum %term and all sub-forums and associated posts have been deleted.', array('%term' => $form_values['name'])));
  watchdog('content', t('forum: deleted %term and all its sub-forums and associated posts.', array('%term' => $form_values['name'])));
  db_query('DELETE FROM {og_term} WHERE tid = %d', $form_values['tid']);
  $return_address = 'og_forum/manage/' .$group_id;
  return $return_address;
}

/**
 * Set a nice breadcrumb for the manage pages
 * TODO I think this isn't quite right.
 */
function _og_forum_manage_breadcrumb($group) {
  $breadcrumb = array();
  $breadcrumb[] = array(
    'path' => 'og_forum',
    'title' => $vocabulary->name
  );
  $breadcrumb[] = array(
    'path' => 'node/' .$group->nid,
    'title' => $group->title
  );
  $breadcrumb[] = array(
  'path' => 'og_forum/manage/' .$group->nid,
    'title' => t('Manage'). ' ' .$group->title. ' ' .t('forums')
  );
  menu_set_location($breadcrumb);
}

/**
 * get an array containing terms associated to this og
 */
function _og_forum_ogterms($group) {
  $result = db_query('SELECT * FROM {og_term} WHERE nid = %d', $group->nid);
  $og_terms = array();
  while ($term = db_fetch_object($result)) {
    $og_terms[] = $term->tid;
  }
  return $og_terms;
}