<?php
// $Id: og.module,v 1.629.2.15 2010-12-26 08:55:59 amitaibu Exp $

/**
 * @file
 * Enable users to create and manage groups with roles and permissions.
 */

define('OG_REQUIRED_CTOOLS_API', '2.0-alpha');

// Load all Field module hooks for Group.
require(drupal_get_path('module', 'og') . '/og.field.inc');

/**
 * Define active group content states.
 */
define('OG_STATE_ACTIVE', 1);

/**
 * Define pending group content states. The user is subscribed to the group but
 * isn't an active member yet.
 */
define('OG_STATE_PENDING', 2);

/**
 * Define blocked group content states. The user is rejected from the group.
 */
define('OG_STATE_BLOCKED', 3);

/**
 * Group audience field.
 */
define('OG_AUDIENCE_FIELD', 'group_audience');

/**
 * Group audience widget.
 */
define('OG_AUDIENCE_WIDGET', 'group_audience');

/**
 * Group audience widget.
 */
define('OG_AUDIENCE_AUTOCOMPLETE_WIDGET', 'group_audience_autocomplete');

/**
 * Group field.
 */
define('OG_GROUP_FIELD', 'group_group');

/**
 * Group default roles and permissions field.
 */
define('OG_DEFAULT_ACCESS_FIELD', 'og_roles_permissions');

/**
 * The role name of group non-members.
 */
define('OG_ANONYMOUS_ROLE', 'non-member');

/**
 * The role name of group member.
 */
define('OG_AUTHENTICATED_ROLE', 'member');

/**
 * The role name of group administrator.
 */
define('OG_ADMINISTRATOR_ROLE', 'administrator member');

/*******************************************************************************
 * Hook implementations
 ******************************************************************************/

/**
 * Implements hook_entity_info().
 */
function og_entity_info() {
  $return['group'] = array(
    'label' => t('Group'),
    'entity class' => 'EntityOg',
    'controller class' => 'EntityAPIController',
    'base table' => 'og',
    'entity keys' => array(
      'id' => 'gid',
    ),
  );
  return $return;
}

/**
 * Implements hook_menu().
 */
function og_menu() {
  $items = array();
  $items['group/autocomplete'] = array(
    'title' => 'group autocomplete',
    'page callback' => 'og_field_audience_autocomplete',
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK
  );
  return $items;
}

/**
 * Implements hook_entity_property_info().
 *
 * Entity metadata hook.
 */
function og_entity_property_info() {
  $info = array();
  $properties = &$info['group']['properties'];

  $properties['gid'] = array(
    'label' => t("Group ID"),
    'type' => 'integer',
    'description' => t("The unique ID of the group."),
    'required' => TRUE,
  );

  $properties['etid'] = array(
    'label' => t("Object ID"),
    'type' => 'integer',
    'description' => t("The ID of the entity."),
    'required' => TRUE,
  );

  $properties['entity_type'] = array(
    'label' => t("Object type"),
    'type' => 'text',
    'description' => t("The entity type."),
    'required' => TRUE,
  );

  $properties['state'] = array(
    'label' => t("State"),
    'type' => 'text',
    'description' => t("The state of the group."),
    'setter callback' => 'entity_metadata_verbatim_set',
    'options list' => 'og_group_states',
  );

  $properties['label'] = array(
    'label' => t("Label"),
    'type' => 'text',
    'description' => t("The label of the entity."),
    'required' => TRUE,
  );

  $properties['created'] = array(
    'label' => t("Date created"),
    'type' => 'date',
    'description' => t("The date the group was created."),
    'setter callback' => 'entity_metadata_verbatim_set',
  );

  return $info;
}

/**
 * Implement hook_modules_enabled().
 */
function og_modules_enabled($modules) {
  foreach ($modules as $module) {
    // Make sure we already have the Drupal 7
    // tables. Otherwise, we skip this, and wait to be called from
    // og_update_7000().
    $access = module_exists('og') && db_table_exists('og') && db_field_exists('og', 'gid');
    if ($access) {
      // Add default roles and permissions, if existing and not set yet.
      og_set_global_access_module($module);
    }
  }
}

/**
 * Implements hook_modules_uninstalled().
 */
function og_modules_uninstalled($modules) {
  // Delete module's permissions.
  og_permissions_delete_by_module($modules);
}

/**
 * Implementation of hook_ctools_plugin_directory().
 */
function og_ctools_plugin_directory($module, $plugin) {
  // Safety: go away if CTools is not at an appropriate version.
  if (!module_invoke('ctools', 'api_version', OG_REQUIRED_CTOOLS_API)) {
    return;
  }

  if ($module == 'ctools') {
    return 'plugins/' . $plugin;
  }
}

/**
 * Implements hook_og_views_relationship().
 *
 * Add relationship information for all core's enteties.
 */
function og_og_views_relationship() {
  $items = array();

  $items['node'] = array(
    'entity' => 'node',
    'views table' => 'node',
    'join field' => 'nid',
  );

  $items['comment'] = array(
    'entity' => 'comment',
    'views table' => 'comment',
    'join field' => 'cid',
  );

  $items['user'] = array(
    'entity' => 'user',
    'views table' => 'users',
    'join field' => 'uid',
  );

  //TODO: Add all enteties.

  return $items;
}

/**
 * Implements hook_permission().
 */
function og_permission() {
  return array(
    'administer group' =>  array(
      'title' => t('Administer Group permissions'),
      'description' => t('Administer all groups and permissions.'),
    ),
  );
}

/**
 * Implement hook_og_permission().
 */
function og_og_permission() {
  // Generate standard node permissions for all applicable node types.
  $perms = array();

  $perms['update group'] = array(
    'title' => t('Edit group'),
    'description' => t('Edit the group. Note: This permission controls only node entity type groups.'),
    'default role' => array(OG_ADMINISTRATOR_ROLE),
  );
  $perms['administer group'] = array(
    'title' => t('Administer group'),
    'description' => t('Manage or block users, and manage their role assignments in the group.'),
    'default role' => array(OG_ADMINISTRATOR_ROLE),
  );

  foreach (node_permissions_get_configured_types() as $type) {
    $perms = array_merge($perms, og_list_permissions($type));
  }

  return $perms;
}


/**
 * Implement hook_og_default_roles()
 */
function og_og_default_roles() {
  return array(OG_ADMINISTRATOR_ROLE);
}

/**
 * Implement hook_node_access()
 */
function og_node_access($node, $op, $account) {
  // If not a group type or the operation is node creation which still has no
  // groups so we can't check it yet, we ignore the access.
  $return = NODE_ACCESS_IGNORE;

  $type = is_string($node) ? $node : (is_array($node) ? $node['type'] : $node->type);
  if (in_array($op, array('update', 'delete'))) {
    if (og_is_group_type('node', $type) && $group = og_get_group('node', $node->nid)) {
      $return = NODE_ACCESS_DENY;
      // The node is a group.
      if (og_user_access($group->gid, $op . ' group', $account)) {
        $return = NODE_ACCESS_ALLOW;
      }
    }
    // A single content type can act as a group and as group content, so make
    // sure that even if the user doesn't have access on the group itself,
    // further access checks are performed.
    // However if we already have access, then skip the following access checks.
    if ($return != NODE_ACCESS_ALLOW && og_is_group_content_type('node', $type) && $gids = og_get_entity_groups('node', $node)) {
      $return = NODE_ACCESS_DENY;
      // We don't have a context, so we need to get all the permissions
      // of all the groups. We don't intersect with the user's group, as
      // groups might allow anonymous members access.
      foreach ($gids as $gid) {
        if (og_user_access($gid, "administer group", $account) ||
          // Any content.
          og_user_access($gid, "$op any $type content", $account) ||
          // Users own content.
          (og_user_access($gid, "$op own $type content", $account) && $node->uid == $account->uid)) {
          $return =  NODE_ACCESS_ALLOW;
          break;
        }
      }
    }
  }

  return $return;
}

/**
 * Implementation of hook_views_api().
 */
function og_views_api() {
  return array(
    'api' => 2,
    'path' => drupal_get_path('module', 'og') . '/includes',
  );
}

/**
 * Implements hook_og_fields_info().
 */
function og_og_fields_info() {
  $items[OG_GROUP_FIELD] = array(
    'type' => array('group'),
    'description' => t('Determine if this should be a group.'),
    'field' => array(
      'field_name' => OG_GROUP_FIELD,
      'no_ui' => TRUE,
      'type' => 'list_boolean',
      'cardinality' => 1,
      'settings' => array(
        'allowed_values' => array(0 => 'Not a group type', 1 => 'Group type'),
        'allowed_values_function' => '',
      ),
    ),
    'instance' => array(
      'label' => t('Group type'),
      'widget_type' => 'options_select',
      'required' => TRUE,
      // Make the group type default.
      'default_value' => array(0 => array('value' => 1)),
      'view modes' => array(
        'full' => array(
          'label' => t('Full'),
          'type' => 'og_group_subscribe',
          'custom settings' => FALSE,
        ),
        'teaser' => array(
          'label' => t('Teaser'),
          'type' => 'og_group_subscribe',
          'custom settings' => FALSE,
        ),
      ),
    ),
  );


  $items[OG_DEFAULT_ACCESS_FIELD] = array(
    'type' => array('group'),
    'description' => t('Determine if group should use default roles and permissions.'),
    'field' => array(
      'field_name' => OG_DEFAULT_ACCESS_FIELD,
      'no_ui' => TRUE,
      'type' => 'list_boolean',
      'cardinality' => 1,
      'settings' => array('allowed_values' => array(0 => 'Use default roles and permissions', 1 => 'Override default roles and permissions'), 'allowed_values_function' => ''),
    ),
    'instance' => array(
      'label' => t('Group roles and permissions'),
      'widget_type' => 'options_select',
      'required' => TRUE,
      // Use default role and permissions as default value.
      'default_value' => array(0 => array('value' => 0)),
      'view modes' => array(
        'full' => array(
          'label' => t('Full'),
          'type' => 'list_default',
          'custom settings' => FALSE,
        ),
        'teaser' => array(
          'label' => t('Teaser'),
          'type' => 'list_default',
          'custom settings' => FALSE,
        ),
      ),
    ),
  );

  $items[OG_AUDIENCE_FIELD] = array(
    'type' => array('group content'),
    'description' => t('Determine to which groups this group content is assigned to.'),
    'field' => array(
      'field_name' => OG_AUDIENCE_FIELD,
      'no_ui' => TRUE,
      'type' => 'group',
      'cardinality' => FIELD_CARDINALITY_UNLIMITED,
    ),
    'instance' => array(
      'label' => t('Groups audience'),
      'widget_type' => OG_AUDIENCE_FIELD,
      'view modes' => array(
        'full' => array(
          'label' => t('Full'),
          'type' => 'og_list_default',
          'custom settings' => FALSE,
        ),
        'teaser' => array(
          'label' => t('Teaser'),
          'type' => 'og_list_default',
          'custom settings' => FALSE,
        ),
      ),
    ),
  );

  return $items;
}


/**
* Implement hook_node_type_delete().
*
* We immediately delete those variables as they are only used to indicate a
* content type should be a group or a group content. However, the actual
* indication for it is in the field API. This is just a workaround, specifically
* for the node entity, to allow users to define groups via the "content type"
* page.
*/
function og_node_type_delete($info) {
  variable_del('og_group_type_' . $info->type);
  variable_del('og_group_content_type_' . $info->type);
}

/**
* Implement hook_node_type_insert().
*/
function og_node_type_insert($info) {
  og_node_type_save($info->type);
}

/**
* Implement hook_node_type_update().
*/
function og_node_type_update($info) {
  og_node_type_save($info->type);
}


/**
 * Return a loaded group entity if exists or create a new one.
 *
 * This is a wrapper function around og_load() that allows passing the group's
 * entity type and entity ID, and the correct group will be loaded according.
 * If no group exists and $create option is set to TRUE a new group entity will
 * be created.
 *
 * @param $etid
 *   The group content ID.
 * @param $entity_type
 *   The group entity type. "node" is the default value. Pass "group" if
 *   content ID is equal to the group unique ID.
 * @param $create
 *   Optional; If no existing group is found, create a new one. Defaults to
 *   FALSE.
 * @param $reset
 *   A boolean indicating that the internal cache should be reset.
 *
 * @return
 *   The group entity if found, or an empty array.
 */
function og_get_group($entity_type, $etid, $create = FALSE, $states = array(OG_STATE_ACTIVE), $reset = FALSE) {
  $group = FALSE;
  if ($gids = og_get_group_ids($entity_type, array($etid), $states, $reset)) {
    // We don't use the entity ID directly, as it might change. For example, if
    // a node is a translation of another node that is a group, we need to load
    // the other node. og_get_group_ids() returns the correct entity ID as the
    // key, so we will use that.
    $correct_etid = key($gids);
    $group = og_load($gids[$correct_etid], $reset);
  }
  elseif ($create) {
    $group = og_create_group(array('entity_type' => $entity_type, 'etid' => $etid));
  }
  return $group;
}


/**
 * Callback to create a new group.
 */
function og_create_group($values = array()) {
  if ($entity = entity_load($values['entity_type'], array($values['etid']))) {
    $entity = current($entity);
    // Add default values.
    $values += array(
      'state' => OG_STATE_ACTIVE,
      'created' => time(),
      'label' => og_entity_label($values['entity_type'], $entity),
    );

    return entity_create('group', $values);
  }
  // Entity couldn't be loaded.
  return FALSE;
}

/**
 * Main class for Group entities provided by Entity API.
 */
class EntityOg extends Entity {
  public function __construct(array $values = array(), $entityType = NULL) {
    parent::__construct($values, 'group');
  }

  public function save() {
    parent::save();
    og_invalidate_cache();
  }

  public function delete() {
    $gid = $this->gid;
    parent::delete();
    og_invalidate_cache(array($gid));

    // Delete roles and permissions.
    og_delete_user_roles_by_group($gid, NULL, TRUE);
  }
}


/**
 * Load multiple Group entities based on certain conditions.
 *
 * @param $gids
 *   An array of group entity IDs.
 * @param $conditions
 *   An array of conditions to match against the {entity} table.
 * @param $reset
 *   A boolean indicating that the internal cache should be reset.
 *
 * @return
 *   An array of group entities, indexed by group ID.
 */
function og_load_multiple($gids = array(), $conditions = array(), $reset = FALSE) {
  return entity_load('group', $gids, $conditions, $reset);
}

/**
 * Load an Group entity from the database.
 *
 * @param $gid
 *   The group ID.
 * @param $reset
 *   Whether to reset the node_load_multiple cache.
 *
 * @return
 *   A fully-populated group entity, or FALSE if none found.
 */
function og_load($gid, $reset = FALSE) {
  $group = og_load_multiple(array($gid), array(), $reset);
  return $group? reset($group) : FALSE;
}

/**
 * Invalidate cache.
 *
 * @param $gids
 *   Array with group IDs that their cache should be invalidated.
 */
function og_invalidate_cache($gids = array()) {
  // Reset static cache.
  $caches = array(
    'og_user_access',
    'og_get_group_ids',
    'og_get_entity_groups',
    'og_field_audience_options',
    'og_user_role_permissions',
  );

  foreach ($caches as $cache) {
    drupal_static_reset($cache);
  }

  // Let other Group modules know we invalidate cache.
  module_invoke_all('og_invalidate_cache', $gids);
}

/**
 * Get group IDs by the entity type and entity IDs.
 *
 * @param $entity_type
 *   The group entity type. Defaults to "group", that will return the group ID.
 * @param $etids
 *   Array with the entity IDs that should be loaded. If FALSE, all groups IDs
 *   that belong to the entity will be returned.
 * @param $states
 *   Array of states the group must be in. Values can be OG_STATE_ACTIVE or
 *   OG_STATE_PENDING. Defaults to OG_STATE_ACTIVE.
 * @param $soft_reset
 *   A boolean indicating that the internal cache should be "soft" reset (i.e.
 *   only the cached values of the specific entity type). For a "hard" reset use
 *   @code
 *     drupal_static_reset('og_get_group_ids');
 *   @endcode
 *
 * @return
 *   Array keyed with the entity ID and the group ID as the value.
 */
function og_get_group_ids($entity_type = 'group', $etids = FALSE, $states = array(OG_STATE_ACTIVE), $soft_reset = FALSE) {
  $gids = &drupal_static(__FUNCTION__, array());

  if ($soft_reset || empty($gids[$entity_type]) || (!empty($gids['__info'][$entity_type]['states'])) && array_diff($gids['__info'][$entity_type]['states'], $states)) {
    $gids[$entity_type] = array();
    // Make sure the cached values are according to the states we are looking
    // for.
    $gids['__info'][$entity_type]['states'] = $states;
    $gids['__info'][$entity_type]['query all'] = FALSE;
  }

  $query_etids = $etids;

  // Check we don't already have the group IDs, and if we have them, return them
  // for the cache.
  if (!empty($gids[$entity_type])) {
    if ($query_etids !== FALSE) {
      $query_etids = array_diff($query_etids, $gids[$entity_type]);

      if (!$query_etids) {
        return array_intersect_key($gids[$entity_type], drupal_map_assoc($etids));
      }
    }
  }

  // Check if we need to query all group, and if this was already cached.
  if ($query_etids === FALSE && $gids['__info'][$entity_type]['query all']) {
    return $gids[$entity_type];
  }

  // Don't query if we already have already queried all.
  if (empty($gids['__info'][$entity_type]['query all'])) {

    if (!empty($query_etids) && $entity_type == 'node' && module_exists('translation')) {
      // If a node is a translation of another node that is a group, we should
      // mark it as a group as-well.
      $query = db_select('node', 'node');
      $query->fields('node', array('tnid', 'tnid'))
      ->condition('nid', $query_etids, 'IN');

      // Add the real group node IDs to the entity IDs that will be queried
      // against the {og} table.
      if ($result = $query->execute()->fetchAllKeyed()) {
        $query_etids = array_merge($query_etids, $result);
        // Add it to the original IDs, as they are needed to later on intersect
        // with the results from the cache.
        $etids = array_merge($etids, $result);
      }
    }

    // We can't use EntityFieldQuery as it return only the group ID, but in
    // order to cache the results we need to maintain a relation between the
    // entity ID and the group ID.
    $query = db_select('og', 'og');

    if ($entity_type == 'group') {
      $query->fields('og', array('gid', 'gid'));
      if (!empty($query_etids)) {
        $query->condition('gid', $query_etids, 'IN');
      }
    }
    else {
      $query->fields('og', array('etid', 'gid'));
      $query->condition('entity_type', $entity_type);

      if (!empty($query_etids)) {
        $query->condition('etid', $query_etids, 'IN');
      }
    }

    if (!empty($states)) {
      $query->condition('state', $states, 'IN');
    }

    $gids[$entity_type] += $query->execute()->fetchAllKeyed();
  }

  // Make sure we return only the ids we were asked for, or if no specific IDs
  // were asked, then return all of them.
  if ($query_etids !== FALSE) {
    $return = array_intersect_key($gids[$entity_type], drupal_map_assoc($etids));
  }
  else {
    $return = $gids[$entity_type];
    // Let the cache know we queried all IDs of this entity type.
    $gids['__info'][$entity_type]['query all'] = TRUE;
  }

  return $return;
}

/**
 * Return all existing groups with a certain state.
 *
 * @param $states
 *   Array of states the group must be in.
 * @param $options
 *   - return query: If TRUE the return value will be the $query object.
 *     Defaults to FALSE.
 *   - count: If TRUE the function will return the total numer of groups in the desired
 *     states. Defaults to FALSE.
 */
function og_get_all_group($states = array(OG_STATE_ACTIVE), $options = array()) {
  // Initialize values.
  $options += array('count' => FALSE, 'return query' => FALSE);
  $return = array();
  $query = db_select('og', 'og');
  $query->addMetaData('id', 'og_get_all_group');
  $query->fields('og', array('gid'));
  if (!empty($states)) {
    // Get only the groups with the correct state.
    $query->condition('state', $states, 'IN');
  }

  if ($options['return query']) {
    // Return the query itself.
    $return = $query;
  }
  elseif ($options['count']) {
    // Return the total number of groups found.
    $return = $query->countQuery()->execute()->fetchField();
  }
  else {
    // Return the group IDs.
    $result = $query->execute()->fetchAll();

    foreach ($result as $value) {
      $return[$value->gid] = $value->gid;
    }
  }

  return $return;
}

/**
 * Set an association (e.g. subscribe) an entity to a group.
 *
 * @param $entity_type
 *   The entity type (e.g. "node" or "user").
 * @param $entity
 *   The entity to set the association.
 * @param $state
 *   The state of the association. Can be:
 *   - OG_STATE_ACTIVE
 *   - OG_STATE_PENDING
 *   - OG_STATE_BLOCKED
 * @param $save
 *   Optional; TRUE if fields value should be saved. Defaults to TRUE.
 *
 * @return
 *   The entity with the fields updated.
 */
function og_group($gid, $entity_type, $entity, $state = OG_STATE_ACTIVE, $save = TRUE) {
  $entity = og_load_entity($entity_type, $entity);
  $property = OG_AUDIENCE_FIELD;
  // Check the audience field exists in the entity.
  if (isset($entity->{$property})) {
    $wrapper = &$entity->{$property}[LANGUAGE_NONE];

    $op = !empty($wrapper[0]['gid']) ? 'update' : 'insert';


    list($id) = entity_extract_ids($entity_type, $entity);
    // Check if the entity is new or an existing one.
    // TODO: make sure is_new is on all entity types.
    $op = empty($entity->is_new) ? 'update' : 'insert';

    if ($op == 'insert') {
      $values = array(
        'gid' => $gid,
        'state' => $state,
        'created' => time(),
      );
      $wrapper[] = $values;
    }
    else {
      $existing_key = FALSE;
      if (!empty($wrapper)) {
        foreach ($wrapper as $key => $value) {
          if ($gid == $value['gid']) {
            $existing_key = $key;
            break;
          }
        }
      }

      if ($existing_key === FALSE) {
        $values = array(
          'gid' => $gid,
          'state' => $state,
          'created' => time(),
        );
        $entity->{$property}[LANGUAGE_NONE][] = $values;

      }
      else {
        if ($wrapper[$existing_key]['state'] != $state) {
          $wrapper[$existing_key]['state'] = $state;
        }
        else {
          // Nothing changed, so don't try to save.
          $save = FALSE;
        }
      }
    }

    if ($save) {
      // Make sure a group isn't created for this entity. This is used for cases
      // that a user object can be a group, however we don't want
      // og_field_crud_group() to actually make it a group when the field
      // attachers are invoked.
      $entity->og_skip_group_create = TRUE;

      entity_save($entity_type, $entity);
      // Unset our temporary property.
      unset($entity->og_skip_group_create);
    }
  }
  return $entity;
}

/**
 * Delete an an association (e.g. unsubscribe) of an entity to a group.
 *
 * @param $entity_type
 *   The entity type (e.g. "node" or "user").
 * @param $entity
 *   The entity to set the association.
 * @param $save
 *   Optioanl; TRUE if fields value shoudl be saved. Defaults to TRUE.
 *
 * @return
 *   The entity with the fields updated.
 */
function og_ungroup($gid, $entity_type, $entity, $save = TRUE) {
  $entity = og_load_entity($entity_type, $entity);
  $property = OG_AUDIENCE_FIELD;

  if (!empty($entity->{$property})) {
    $wrapper = &$entity->{$property}[LANGUAGE_NONE];

    $existing_key = FALSE;
    if (!empty($wrapper)) {
      foreach ($wrapper as $key => $value) {
        if ($gid == $value['gid']) {
          $existing_key = $key;
          break;
        }
      }
    }
    if ($existing_key !== FALSE) {
      unset($wrapper[$existing_key]);

      if ($save) {
        entity_save($entity_type, $entity);

        if ($entity_type == 'user') {
          foreach (og_get_user_roles($gid, $entity->uid) as $rid) {
            og_users_roles_revoke($gid, $entity->uid, $rid);
          }
        }
      }
    }
  }
  return $entity;
}

/**
 * Determine whether a user has a given privilege.
 *
 * @param $gid
 *   The group ID.
 * @param $string
 *   The permission, such as "administer nodes", being checked for.
 * @param $account
 *   (optional) The account to check, if not given use currently lgroupged in user.
 *
 * @return
 *   Boolean TRUE if the current user has the requested permission.
 *
 * All permission checks in OG should go through this function. This
 * way, we guarantee consistent behavior, and ensure that the superuser
 * can perform all actions.
 */
function og_user_access($gid, $string, $account = NULL) {
  if (variable_get('og_skip_access', FALSE)) {
    // User access should always return TRUE, as Group is requested to
    // skip any access check.
    return TRUE;
  }

  global $user;
  $perm = &drupal_static(__FUNCTION__, array());

  if (empty($account)) {
    $account = clone $user;
  }

  // User #1 has all privileges.
  if ($account->uid == 1) {
    return TRUE;
  }

  // Administer Group permission.
  if (user_access('administer group', $account)) {
    return TRUE;
  }

  if (!($group = og_load($gid))) {
    // Not a group.
    return FALSE;
  }

  // Group manager has all privileges (if variable is TRUE).
  if (variable_get('og_group_manager_full_access', TRUE)) {
    $entity = current(entity_load($group->entity_type, array($group->etid)));
    if (!empty($entity->uid) && $entity->uid == $account->uid) {
      return TRUE;
    }
  }

  // To reduce the number of SQL queries, we cache the user's permissions
  // in a static variable.
  if (!isset($perm[$gid][$account->uid])) {
    $roles = og_get_user_roles($gid, $account->uid);
    $role_permissions = og_user_role_permissions($roles);

    $perms = array();
    foreach ($role_permissions as $one_role) {
      $perms += $one_role;

      $perm[$gid][$account->uid] = $perms;
    }
  }

  return isset($perm[$gid][$account->uid][$string]);
}


/**
 * Add group and group content fields to new content types.
 *
 * @param $bundle_name
 *   The content type name.
 */
function og_node_type_save($bundle_name) {
  if (variable_get('og_group_type_' . $bundle_name, 'omitted') == 'group') {
    og_create_field(OG_GROUP_FIELD,'node', $bundle_name);
    // Delete the variable, as we will rely on the presence of th field.
    variable_del('og_group_type_' . $bundle_name);
  }
  if (variable_get('og_group_content_type_' . $bundle_name, 'omitted') == 'og_content') {
    og_create_field(OG_AUDIENCE_FIELD,'node', $bundle_name);
    // Delete the variable, as we will rely on the presence of th field.
    variable_del('og_group_content_type_' . $bundle_name);
  }
}


/*******************************************************************************
 * API functions
 ******************************************************************************/

/**
 * Get the groups a content is associated with.
 *
 * @param $entity_type
 *   The entity type (e.g. "node" or "user").
 * @param $entity
 *   The entity can be a user, node or any fieldable entity.
 * @param $states
 *   Optional; Array with the state to return. If empty groups of all state will
 *   return.
 * @return
 *  An array with the group IDs, or an empty array.
 */
function og_get_entity_groups($entity_type, $entity, $states = array(OG_STATE_ACTIVE)) {
  $groups = &drupal_static(__FUNCTION__, array());

  // Get the entity ID.
  list($id) = entity_extract_ids($entity_type, $entity);

  if (!empty($groups[$entity_type][$id])) {
    return $groups[$entity_type][$id];
  }

  $entity = og_load_entity($entity_type, $entity);
  $property = OG_AUDIENCE_FIELD;

  $wrapper = &$entity->{$property}[LANGUAGE_NONE];

  $gids = array();
  if (!empty($wrapper)) {
    foreach ($wrapper as $group) {
      if (!empty($states) && !in_array($group['state'], $states)) {
        // Don't register the group if it's state isn't the one we look for.
        continue;
      }
      $gids += drupal_map_assoc(array($group['gid']));
    }
  }

  $groups[$entity_type][$id] = $gids;
  return $groups[$entity_type][$id];
}

/**
 * Return the group type (i.e. "group" or "group_content") of an entity.
 *
 * @param $bundle_name
 *   The bundle name to be checked.
 * @param $entity_type
 *   The entity type.
 * @param $type
 *   The group usage type. Must be "group" or "group content".
 *
 * @return
 *   The group type or an "omitted" if node type doesn't participate in
 *   Group.
 */
function og_get_group_type($entity_type, $bundle_name, $type = 'group') {
  if ($type == 'group') {
    return (bool)field_info_instance($entity_type, OG_GROUP_FIELD, $bundle_name);
  }
  elseif ($type == 'group content') {
    return (bool)field_info_instance($entity_type, OG_AUDIENCE_FIELD, $bundle_name);
  }
}

/**
 * Return TRUE if the entity type is a "group" type.
 *
 * This is a wrapper function around og_get_group_type().
 *
 * @param $node_type
 *   The node type to be checked.
 */
function og_is_group_type($entity_type, $bundle_name) {
  return og_get_group_type($entity_type, $bundle_name);
}

/**
 * Return TRUE if the entity type is a "group content" type.
 *
 * This is a wrapper function around og_get_group_type().
 *
 * @param $node_type
 *   The node type to be checked.
 */
function og_is_group_content_type($entity_type, $bundle_name) {
  return og_get_group_type($entity_type, $bundle_name, 'group content');
}

/**
 * Return all the enteties that are a group.
 *
 * @return
 *   Array keyed with the entity type machine name and the entity human readable
 *   name as the value, or an empty array if no enteties are defined as group.
 */
function og_get_all_group_entity() {
  $return = array();

  foreach (entity_get_info() as $entity_type => $entity_value) {
    if (!empty($entity_value['fieldable'])) {
      foreach ($entity_value['bundles'] as $bundle => $bundle_value) {
        if (og_is_group_type($entity_type, $bundle)) {
          $return[$entity_type] = check_plain($entity_value['label']);
          // At least one bundle of the entity can be a group, so break.
          break;
        }
      }
    }
  }
  return $return;
}

/**
 * Return TRUE if entity belongs to a group.
 *
 * @param $gid
 *   The group ID.
 * @param $entity_type
 *   The entity type.
 * @param $entity
 *   The entity object. If empty the current user will be used.
 *
 * @return
 *   TRUE if the entity (e.g. the user) belongs to a group and is not pending or
 *   blocked.
 */
function og_is_member($gid, $entity_type = 'user', $entity = NULL, $states = array(OG_STATE_ACTIVE)) {
  if ($entity_type == 'user' && empty($entity)) {
    global $user;
    $entity = clone $user;
  }
  $entity = og_load_entity($entity_type, $entity);
  $groups = og_get_entity_groups($entity_type, $entity, $states);
  return in_array($gid, $groups);
}

/**
 * Wrapper of og_user_access(); Gets entity ID instead of group ID.
 *
 * Can be used as a menu callback.
 *
 * @param $perm
 *   The permissions name.
 * @param $entity_type
 *   The entity type.
 * @param $entity
 *   The entity object.
 * @param $account
 *   Optioanl; The user related to the action. For example if the operation is
 *   "subscribe" then the account will be the subscribing user.
 *
 * @return
 *   TRUE if access is allowed, otherise FALSE.
 */
function og_user_access_by_entity($perm, $entity_type = NULL, $etid = NULL, $account = NULL) {
  if (empty($account)) {
    global $user;
    $account = clone($user);
  }

  if ($group = og_get_group($entity_type, $etid)) {
    return og_user_access($group->gid, $perm, $account);
  }
  return FALSE;
}

/**
 * Get the state of an entity in a group.
 *
 * @param $entity_type
 *   The entity type.
 * @param $entity
 *   The entity object.
 * @param $gid
 *   The group ID.
 * @return
 *   The state value, or FALSE is entity is not associated with group.
 */
function og_get_entity_state($gid, $entity_type, $entity) {
  $state = FALSE;

  $entity = og_load_entity($entity_type, $entity);
  $property = OG_AUDIENCE_FIELD;

  $wrapper = &$entity->{$property}[LANGUAGE_NONE];

  if (!empty($wrapper)) {
    foreach ($wrapper as $key => $value) {
      if ($value['gid'] == $gid) {
        $state = $value['state'];
        break;
      }
    }
  }
  return $state;
}

/**
 * Check if group should use default roles and permissions.
 *
 * @param $gid
 *   The group ID.
 * @return
 *   TRUE if group should use default roles and permissions.
 */
function og_is_group_default_access($gid) {
  $return = TRUE;
  if ($entity = og_load_entity_from_group($gid)) {

    $property = OG_DEFAULT_ACCESS_FIELD;

    if (!empty($entity->{$property}[LANGUAGE_NONE]) && $wrapper = $entity->{$property}[LANGUAGE_NONE]) {
      $return = empty($wrapper[0]['value']);
    }
  }

  return $return;
}


/**
 * Select groups if they were passed in the URL.
 *
 * You can pass a URL in in the form of
 * node/add/post?gids_group[]=1,2,3&gids_node[]=4,5,6
 * Note that gids_ is the prefix followed by the entity type (e.g. "node",
 * "user") or "group" to indicate the passed values are group ID.
 */
function og_get_context_by_url() {
  $return = array();
  foreach (array_keys(entity_get_info()) as $entity_type) {
    $etids =  !empty($_GET['gids_' . $entity_type][0]) ? explode(',', $_GET['gids_' . $entity_type][0]) : array();
    if ($etids) {
      $return = array_merge($return, og_get_group_ids($entity_type, $etids));
    }
  }
  return $return;
}

/**
 * Get labels out of a list of group IDs.
 *
 * @param $gids
 *   The group IDs.
 *
 * @return
 *   Array keyed with the group ID, and the entity label as the value, or else
 *   the group ID with the entity type and entity ID, sanitized.
 */
function og_label_multiple($gids = array()) {
  $labels = array();
  $groups = og_load_multiple($gids);
  foreach ($groups as $group) {
    if (!empty($group->label)) {
      $labels[$group->gid] = check_plain($group->label);
    }
    else {
      $entity = entity_get_info($group->entity_type);
      $param = array(
        '@gid' => $group->gid,
        '@entity' => $entity['label'],
        '@etid' => $group->etid,
      );
      $labels[$group->gid] = t('Group @gid - @entity ID @etid', $param);
    }
  }
  return $labels;
}

/**
 * Wrapper function; Get the label of a single group.
 *
 * @param $gid
 *   The group ID.
 *
 * @return
 *   The label of the group if found, or else the group ID with the entity type
 *   and entity ID, sanitized.
 */
function og_label($gid) {
  $labels = og_label_multiple(array($gid));
  return $labels[$gid];
}


/**
 * Determine the permissions for one or more roles.
 *
 * @param $roles
 *   An array whose keys are the role IDs of interest.
 *
 * @return
 *   An array indexed by role ID. Each value is an array whose keys are the
 *   permission strings for the given role ID.
 */
function og_user_role_permissions($roles = array()) {
  $cache = &drupal_static(__FUNCTION__, array());

  $role_permissions = $fetch = array();

  if ($roles) {
    foreach ($roles as $rid => $name) {
      if (isset($cache[$rid])) {
        $role_permissions[$rid] = $cache[$rid];
      }
      else {
        // Add this rid to the list of those needing to be fetched.
        $fetch[] = $rid;
        // Prepare in case no permissions are returned.
        $cache[$rid] = array();
      }
    }

    if ($fetch) {
      // Get from the database permissions that were not in the static variable.
      // Only role IDs with at least one permission assigned will return rows.
      $result = db_query("SELECT rid, permission FROM {og_role_permission} WHERE rid IN (:fetch)", array(':fetch' => $fetch));

      foreach ($result as $row) {
        $cache[$row->rid][$row->permission] = TRUE;
      }
      foreach ($fetch as $rid) {
        // For every rid, we know we at least assigned an empty array.
        $role_permissions[$rid] = $cache[$rid];
      }
    }
  }

  return $role_permissions;
}

/**
 * Retrieve an array of roles matching specified conditions.
 *
 * @param $gid
 *   The group node ID.
 * @param $permission
 *   Optional; A string containing a permission. If set, only roles containing
 *   that permission are returned.
 * @param $force_group
 *   Optioanl; If TRUE then the roles of the group will be retrieved by the
 *   group ID, even if the group is set to have default roles and permissions.
 *   The group might be set to "Default access" but infact there are inactive
 *   group roles. Thus, we are forcing the function to return the overriden
 *   roles. see og_delete_user_roles_by_group().
 *
 * @return
 *   An associative array with the role id as the key and the role name as
 *   value. The anonymous and authenticated deault roles are on the top of the
 *   array.
 */
function og_user_roles($gid = 0, $permission = NULL, $force_group = FALSE) {
  $roles = array();

  // Check if overriden access exists.
  if (!$force_group) {
    $gid = og_is_group_default_access($gid) ? 0 : $gid;
  }

  if (!empty($permission)) {
    $roles = db_query("SELECT r.rid, r.name FROM {og_role} r INNER JOIN {og_role_permission} p ON r.rid = p.rid WHERE p.permission = :permission AND r.gid = :gid ORDER BY r.name", array(':permission' => $permission, ':gid' => $gid))->fetchAllKeyed();
  }
  else {
    $roles = db_query("SELECT rid, name FROM {og_role} WHERE gid = :gid ORDER BY rid", array(':gid' => $gid))->fetchAllKeyed();
  }

  return  $roles;
}

/**
 * Get global roles - roles that belong to non-existent group ID 0.
 *
 * @return
 *   A keyed array with role Id as key and role name as value.
 */
function og_get_global_roles() {
  return og_user_roles();
}

/**
 * Get default roles.
 */
function og_get_default_roles($include = TRUE) {
  $roles = array();
  foreach (module_implements('og_default_roles') as $module) {
    $roles[$module] = module_invoke($module, 'og_default_roles');
  }

  // Allow other modules to alter the defult roles, excpet of the anonymous and
  // authenticated.
  drupal_alter('og_default_roles', $roles);

  if ($include) {
    $roles += array('og' => array());
    array_unshift($roles['og'], OG_ANONYMOUS_ROLE, OG_AUTHENTICATED_ROLE);
  }

  return $roles;
}

/**
 * Add default roles and permissions of a module to the global permissions.
 *
 * This function is called whenever a module is enabled. Calling this function
 * directly will re-assign permissions to thier default roles.
 *
 * @param $module
 *   The module name.
 * @return
 *   Array with the global roles, as new records might have been added.
 */
function og_set_global_access_module($module) {
  $default_roles = og_get_default_roles();
  $global_roles = og_get_global_roles();
  $permissions = og_get_permissions();

  // The roles that should be added.
  $roles_to_add = array();

  if (empty($global_roles)) {
    // Add all the roles, there are no roles defined yet. This is probably
    // becuase OG is only being installed.
    $roles_to_add = reset($default_roles);
  }
  elseif (!empty($default_roles[$module])) {
    // Diff the roles that should be added with the ones already defined as
    // global roles.
    $roles_to_add = array_diff($default_roles[$module], $global_roles);
  }

  // Add a new global role.
  if (!empty($roles_to_add)) {
    foreach ($roles_to_add as $name) {
      $role = og_create_global_role($name);
      $global_roles[$role->rid] = $name;
    }
  }

  // If there are permissions defined, make sure they were not applied already,
  // as it might happen if a module was disabled and re-enabled.
  $perms_to_add = array();
  $perms_to_add_by_rid = array();

  foreach ($permissions as $key => $value) {
    if ($value['module'] == $module) {
      $perms_to_add[$key] = $value;
    }
  }

  if ($perms_to_add) {
    // Get the assigned permissions of the global roles.
    $global_roles_perms = og_user_role_permissions($global_roles);

    // Get the roles keyed by thier name.
    $global_roles_flip = array_flip($global_roles);
    foreach ($perms_to_add as $key => $value) {
      if (!empty($value['default role'])) {
        // Don't try to assign permissions that are already assigned.
        foreach ($value['default role'] as $role) {
          $rid = $global_roles_flip[$role];
          if (empty($global_roles_perms[$rid][$key])) {
            // Get the  permissions to be added in the form:
            // array(
            //   '1' => array( // '1' is the role ID.
            //     'perm_foo' => 'perm_foo',
            //     'perm_bar' => 'perm_bar',
            //    ),
            // );
            $perms_to_add_by_rid[$rid][$key] = $key;
          }
        }
      }
    }
  }

  if ($perms_to_add_by_rid) {
    foreach ($perms_to_add_by_rid as $rid => $perms) {
      // Assign the permissions to the roles.
      og_user_role_change_permissions($rid, $perms);
    }
  }

  return $global_roles;
}

/**
 * Add a new global role - a role associated to group ID 0.
 *
 * @param $name
 *   The role name.
 * @return
 *   The role object populated iwth the role ID.
 */
function og_create_global_role($name) {
  $role = new stdClass;
  $role->name = $name;
  $role->gid = 0;

  og_user_role_save($role);
  return $role;
}

/**
 * Get all roles of a user in a certain group.
 *
 * @param $gid
 *   The group ID.
 * @param $uid
 *   The user ID.
 * @param $include
 *   Optional; If TRUE also anonymous or authenticated role ID will be returned.
 *   Defaults to TRUE.
 * @return
 *   Array with the role IDs of the user.
 */
function og_get_user_roles($gid, $uid = NULL, $include = TRUE) {
  $roles = array();

  if (empty($uid)) {
    global $user;
    $uid = $user->uid;
  }

  if ($include) {
    // Check if overriden access exists.
    $query_gid = og_is_group_default_access($gid) ? 0 : $gid;

    $group_roles = og_user_roles($query_gid);
    $account = user_load($uid);

    $name = og_is_member($gid, 'user', $account) ? OG_AUTHENTICATED_ROLE : OG_ANONYMOUS_ROLE;
    $rid = array_search($name, $group_roles);
    $roles[$rid] = $rid;
  }

  $roles = $roles + db_query("SELECT rid, rid FROM {og_users_roles} WHERE uid = :uid AND gid = :gid", array(':uid' => $uid, ':gid' => $gid))->fetchAllKeyed();

  return $roles;
}

/**
 * Get all the users with certain roles in a group.
 *
 * @param $gid
 *   The group unique ID.
 * @param $roles
 *   Array with the role IDs to query.
 */
function og_get_users_by_roles($gid, $rids = array()) {
  $query = db_select('og_users_roles', 'og_users_roles');
  return $query->fields('og_users_roles', array('uid'))
    ->condition('gid', $gid)
    ->condition('rid', $rids, 'IN')
    ->execute()
    ->fetchAll();
}


/**
 * Fetch a user role from database.
 *
 * @param $role
 *   An integer with the role ID.
 * @return
 *   A fully-loaded role object if a role with the given name or ID
 *   exists, FALSE otherwise.
 */
function og_user_role_load($rid) {
  return db_select('og_role', 'r')
    ->fields('r')
    ->condition('rid', $rid)
    ->execute()
    ->fetchObject();
}
/**
 * Save a user role to the database.
 *
 * @param $role
 *   A role object to modify or add. If $role->rid is not specified, a new
 *   role will be created.
 * @return
 *   Status constant indicating if role was created or updated.
 *   Failure to write the user role record will return FALSE. Otherwise.
 *   SAVED_NEW or SAVED_UPDATED is returned depending on the operation
 *   performed.
 */
function og_user_role_save($role) {
  if ($role->name) {
    // Prevent leading and trailing spaces in role names.
    $role->name = trim($role->name);
  }
  if (!empty($role->rid) && $role->name) {
    $status = drupal_write_record('og_role', $role, 'rid');
    module_invoke_all('og_user_role_update', $role);
  }
  else {
    $status = drupal_write_record('og_role', $role);
    module_invoke_all('og_user_role_insert', $role);
  }

  og_invalidate_cache();

  return $status;
}

/**
 * Delete a user role from database.
 *
 * @param $role
 *   An integer with the role ID.
 */
function og_user_role_delete($rid) {
  $role = og_user_role_load($rid);

  db_delete('og_role')
    ->condition('rid', $rid)
    ->execute();
  db_delete('og_role_permission')
    ->condition('rid', $rid)
    ->execute();
  // Update the users who have this role set.
  db_delete('og_users_roles')
    ->condition('rid', $rid)
    ->execute();

  module_invoke_all('og_user_role_delete', $role);

  og_invalidate_cache();
}

/**
 * Delete all roles belonging to a group.
 *
 * @param $gid
 *   The group ID.
 */
function og_delete_user_roles_by_group($gid) {
  // Check if group has overriden roles defined.
  if ($roles = og_user_roles($gid, NULL, TRUE)) {
    foreach ($roles as $rid => $name) {
      og_user_role_delete($rid);
    }
  }
}

/**
 * Get the role names of role IDs.
 *
 * @param $rids
 *   Array with role IDs.
 * @return
 *  Array keyed by the role ID, and the role name as the value.
 */
function og_get_user_roles_name($rids = array()) {
  return db_query("SELECT rid, name FROM {og_role} WHERE rid IN (:rids)", array(':rids' => $rids))->fetchAllKeyed();
}


/**
 * Delete all permissions defined by a module.
 *
 * @see og_modules_uninstalled()
 *
 * @param $module
 *   Array with the modules name.
 */
function og_permissions_delete_by_module($modules = array()) {
   db_delete('og_role_permission')
     ->condition('module', $modules, 'IN')
     ->execute();
}

/**
 * Create new roles, based on the default roles and permissions.
 *
 * @param $gid
 *   The group ID.
 * @return
 *   The newly created roles keyed by role ID and role name as the value. Or
 *   FALSE if no roles were created.
 */
function og_user_roles_override($gid) {
  // Check if roles aren't already overriden. We can't use
  // og_is_group_default_access() as the field is already set, so we
  // check to see if there are new roles in the database and compare
  // them with the default roles.
  // TODO: We can add a key to the $group object that will indicate this
  // if performance will be poor.

  if ($roles = og_user_roles($gid, NULL, TRUE)) {
    return;
  }

  $rids = array();
  // Make sure roles doesn't exist already by looking for a row with the group
  // ID in {og_role} table.
  $perms = og_get_global_permissions();

  foreach (og_get_global_roles() as $rid => $name) {
    $role = new stdClass;
    $role->name = $name;
    $role->gid = $gid;

    og_user_role_save($role);
    $rids[$role->rid] = $role->name;
    og_user_role_change_permissions($role->rid, $perms[$rid]);
  }

  return $rids;
}

/**
 * Grant a group role to a user.
 *
 * @param $uid
 *   The user ID.
 * @param $rid
 *   The role ID.
 */
function og_users_roles_grant($gid, $uid, $rid) {
  // Get the existiong user roles.
  $user_roles = og_get_user_roles($gid, $uid);
  if (!in_array($rid, $user_roles)) {
    $role = new stdClass();
    $role->uid = $uid;
    $role->rid = $rid;
    $role->gid = $gid;

    drupal_write_record('og_users_roles', $role);
    module_invoke_all('og_users_roles_grant', $gid, $uid, $rid);
  }
}

/**
 * Revoke a group role from a user.
 *
 * @param $uid
 *   The user ID.
 * @param $rid
 *   The role ID.
 */
function og_users_roles_revoke($gid, $uid, $rid) {
  // Get the existiong user roles.
  $user_roles = og_get_user_roles($gid, $uid);
  if (in_array($rid, $user_roles)) {

    db_delete('og_users_roles')
      ->condition('uid', $uid)
      ->condition('rid', $rid)
      ->execute();
    module_invoke_all('og_users_roles_revoke', $gid, $uid, $rid);
  }
}

/**
 * Change permissions for a user role.
 *
 * This function may be used to grant and revoke multiple permissions at once.
 * For example, when a form exposes checkboxes to configure permissions for a
 * role, the submitted values may be directly passed on in a form submit
 * handler.
 *
 * @param $rid
 *   The ID of a group user role to alter.
 * @param $permissions
 *   An array of permissions, where the key holds the permission name and the
 *   value is an integer or boolean that determines whether to grant or revoke
 *   the permission:
 *   @code
 *     array(
 *       'edit group' => 0,
 *       'administer group' => 1,
 *     )
 *   @endcode
 *   Existing permissions are not changed, unless specified in $permissions.
 *
 * @see og_user_role_grant_permissions()
 * @see og_user_role_revoke_permissions()
 */
function og_user_role_change_permissions($rid, array $permissions = array()) {
  // Grant new permissions for the role.
  $grant = array_filter($permissions);
  if (!empty($grant)) {
    og_user_role_grant_permissions($rid, array_keys($grant));
  }
  // Revoke permissions for the role.
  $revoke = array_diff_assoc($permissions, $grant);
  if (!empty($revoke)) {
    og_user_role_revoke_permissions($rid, array_keys($revoke));
  }
}

/**
 * Grant permissions to a user role.
 *
 * @param $rid
 *   The ID of a user role to alter.
 * @param $permissions
 *   A list of permission names to grant.
 *
 * @see user_role_change_permissions()
 * @see user_role_revoke_permissions()
 */
function og_user_role_grant_permissions($rid, array $permissions = array()) {
  $modules = array();
  foreach (og_get_permissions() as $name => $value) {
    $modules[$name] = $value['module'];
  }
  // Grant new permissions for the role.
  foreach ($permissions as $name) {
    // Prevent WSOD, if the permission name is wrong, and we can't find its
    // module.
    if (!empty($modules[$name])) {
      db_merge('og_role_permission')
        ->key(array(
          'rid' => $rid,
          'permission' => $name,
          'module' => $modules[$name],
        ))
        ->execute();
    }
  }
  og_invalidate_cache();
}

/**
 * Revoke permissions from a user role.
 *
 * @param $rid
 *   The ID of a user role to alter.
 * @param $permissions
 *   A list of permission names to revoke.
 *
 * @see user_role_change_permissions()
 * @see user_role_grant_permissions()
 */
function og_user_role_revoke_permissions($rid, array $permissions = array()) {
  // Revoke permissions for the role.
  db_delete('og_role_permission')
    ->condition('rid', $rid)
    ->condition('permission', $permissions, 'IN')
    ->execute();

  og_invalidate_cache();
}


/**
 * Get all permissions defined for Group.
 *
 * @return
 *  Array keyed with the permissions name and the value of the permissions.
 *  TODO: Write the values.
 */
function og_get_permissions() {
  $perms = &drupal_static(__FUNCTION__, array());
  if (!empty($perms)) {
    return $perms;
  }

  foreach (module_implements('og_permission') as $module) {
    if ($permissions = module_invoke($module, 'og_permission')) {
      foreach ($permissions as $key => $perm) {
        $permissions[$key] += array(
          // Initialize the roles key, if other modules haven't set it
          // explicetly. This means the permissions can apply to anonymous and
          // authenticated members as-well.
          'roles' => array(OG_ANONYMOUS_ROLE, OG_AUTHENTICATED_ROLE),
          'default role' => array(),
          'module' => $module,
        );
      }
      $perms = array_merge($perms, $permissions);
    }
  }

  // Allow other modules to alter the permissions.
  drupal_alter('og_permission', $perms);

  return $perms;
}

/**
 * Get global permissions.
 *
 * @return
 *   Array keyed with the anonymous, authenticated and administror and the
 *   permissions that should be enabled by default.
 */
function og_get_global_permissions() {
  $roles = og_get_global_roles();

  $perms = og_user_role_permissions($roles);
  return $perms;
}

/**
 * Get all the modules fields that can be assigned to fieldable enteties.
 */
function og_fields_info($field_name = NULL) {
  $return = &drupal_static(__FUNCTION__, array());

  if (empty($return)) {
    foreach (module_implements('og_fields_info') as $module) {
      if ($fields = module_invoke($module, 'og_fields_info')) {
        foreach ($fields as $key => $field) {
          // Add default values.
          $field += array(
            'entity type' => array(),
          );

          // Add the module information.
          $return[$key] = array_merge($field, array('module' => $module));
        }
      }
    }

    // Allow other modules to alter the field info.
    drupal_alter('og_fields_info', $return);
  }

  return empty($field_name) ? $return : $return[$field_name];
}

/**
 * Check to see if a token value matches the specified node.
 */
function og_check_token($token, $seed) {
  return drupal_get_token($seed) == $token;
}

/**
 * Set breadcrumbs according to a given group.
 *
 * @param $entity_type
 *   The entity type.
 * @param $etid
 *   The entity ID.
 * @param $path
 *   Optional; The path to append to the breadcrumb.
 */
function og_set_breadcrumb($entity_type, $etid, $path = array()) {
  if ($entity = entity_load($entity_type, array($etid))) {
    $entity = reset($entity);
    $label = og_entity_label($entity_type, $entity);
    drupal_set_breadcrumb(array_merge(array(l(t('Home'), '<front>')), array(l($label, "$entity_type/$etid")), $path)) ;
  }
}

/**
 * Create an organic groups field in a bundle.
 *
 * @param $field_name
 *   The field name
 * @param $entity_type
 *   The entity type
 * @param $bundle
 *   The bundle name.
 */
function og_create_field($field_name, $entity_type, $bundle) {
  if ($group_field = og_fields_info($field_name)) {

    $field = field_info_field($field_name);
    if (empty($field)) {
      $field = field_create_field($group_field['field']);
    }

    $instance = field_info_instance($entity_type, $field_name, $bundle);
    if (empty($instance)) {
      $instance = $group_field['instance'];
      $instance += array(
        'field_name' => $field_name,
        'bundle' => $bundle,
        'entity_type' => $entity_type,
      );

      field_create_instance($instance);
    }
  }
}

/**
 * Return a re-loaded entity with its fields.
 *
 * This is needed only if a user account is passed, as global $user is only a
 * partial user entity.
 *
 * @param $entity_type
 *   The entity type.
 * @param $entity
 *   The entity.
 */
function og_load_entity($entity_type, $entity) {
  if ($entity_type == 'user') {
    $entity = user_load($entity->uid);
  }
  return $entity;
}

/**
 * Return a loaded entity from group.
 *
 * @param $gid
 *   The group ID.
 */
function og_load_entity_from_group($gid) {
  $entity = FALSE;
  if ($group = og_load($gid)) {
    $entity = entity_load($group->entity_type, array($group->etid));
    $entity = reset($entity);
  }

  return $entity;
}


/**
 * Return the states a group can be in.
 */
function og_group_states() {
  return array(
    OG_STATE_ACTIVE => t('Active'),
    OG_STATE_PENDING => t('Pending'),
  );
}

/**
 * Return the states a group can be in.
 */
function og_group_content_states() {
  return array(
    OG_STATE_ACTIVE => t('Active'),
    OG_STATE_PENDING => t('Pending'),
    OG_STATE_BLOCKED => t('Blocked'),
  );
}

/**
 * Wrapper function for entity_label() to return some text if label isn't found.
 *
 * @param $entity_type
 *   The entity type.
 * @param $entity
 *   The entity object.
 */
function og_entity_label($entity_type, $entity) {
  $label = '';
  if (!empty($entity)) {
    $label = entity_label($entity_type, $entity);
    if (!$label) {
      list($id) = entity_extract_ids($entity_type, $entity);
      $label = t('Entity @entity_type ID @id', array('@entity_type' => $entity_type, '@id' => $id));
    }
  }
  return $label;
}

/**
 * Helper function to generate standard node permission list for a given type.
 *
 * @param $type
 *   The machine-readable name of the node type.
 * @return array
 *   An array of permission names and descriptions.
 */
function og_list_permissions($type) {
  $perms = array();

  // Check type is of group content.
  if (og_is_group_content_type('node', $type)) {
    $info = node_type_get_type($type);
    $type = check_plain($info->type);

    // Build standard list of node permissions for this type.
    $perms = array(
      "update own $type content" => array(
        'title' => t('Edit own %type_name content', array('%type_name' => $info->name)),
      ),
      "update any $type content" => array(
        'title' => t('Edit any %type_name content', array('%type_name' => $info->name)),
      ),
      "delete own $type content" => array(
        'title' => t('Delete own %type_name content', array('%type_name' => $info->name)),
      ),
      "delete any $type content" => array(
        'title' => t('Delete any %type_name content', array('%type_name' => $info->name)),
      ),
    );

    // Add default permissions.
    foreach ($perms as $key => $value) {
      $perms[$key]['default role'] = array(OG_AUTHENTICATED_ROLE);
    }
  }
  return $perms;
}