og.module

<?php

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

// Add field widget related code.
require DRUPAL_ROOT . '/' . drupal_get_path('module', 'og') . '/includes/og.field.inc';

/**
 * Define active group content states.
 *
 * When a user has this membership state they are considered to be of
 * "member" role.
 */
define('OG_STATE_ACTIVE', 1);

/**
 * Define pending group content states. The user is subscribed to the group
 * but isn't an active member yet.
 *
 * When a user has this membership state they are considered to be of
 * "non-member" role.
 */
define('OG_STATE_PENDING', 2);

/**
 * Define blocked group content states. The user is rejected from the group.
 *
 * When a user has this membership state they are denided access to any
 * group related action. This state, however, does not prevent user to
 * access a group or group content node.
 */
define('OG_STATE_BLOCKED', 3);

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

/**
 * 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');

/**
 * The default group membership type that is the bundle of group membership.
 */
define('OG_MEMBERSHIP_TYPE_DEFAULT', 'og_membership_type_default');

/**
 * The name of the user's request field in the default group membership type.
 */
define('OG_MEMBERSHIP_REQUEST_FIELD', 'og_membership_request');

/**
 * Implements hook_help().
 */
function og_help($path, $arg) {
  switch ($path) {
    case 'admin/help#og':
      $path = drupal_get_path('module', 'og');
      $output  = '<p>' . t("Read the <a href='@url'>README.txt</a> file in the Organic groups module directory.", array('@url' => "/$path/README.txt")) . '</p>';
      $output .= '<p>' . t("Information about Organic Groups can also be found on the module's<a href='@og'>documentation page</a>.", array('@og' => 'http://drupal.org/documentation/modules/og')) . '</p>';
      return $output;
  }
}

/**
 * Implements hook_menu().
 */
function og_menu() {
  $items = array();

  // Add our own autocomplete callback to pass also the group and
  // vocabulary info.
  $items['og/autocomplete/single/%/%/%/%'] = array(
    'title' => 'Entity Reference Autocomplete',
    'page callback' => 'og_entityreference_autocomplete_callback',
    'page arguments' => array(2, 3, 4, 5, 6),
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
  );
  $items['og/autocomplete/tags/%/%/%/%'] = array(
    'title' => 'Entity Reference Autocomplete',
    'page callback' => 'og_entityreference_autocomplete_callback',
    'page arguments' => array(2, 3, 4, 5, 6),
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
  );

  return $items;
}

/**
 * Implements hook_entity_info().
 */
function og_entity_info() {
  $items['og_membership_type'] = array(
    'label' => t('OG membership type'),
    'controller class' => 'EntityAPIControllerExportable',
    'entity class' => 'OgMembershipType',
    'base table' => 'og_membership_type',
    'fieldable' => TRUE,
    'entity keys' => array(
      'id' => 'id',
      'label' => 'description',
      'name' => 'name',
    ),
    'exportable' => TRUE,
    'export' => array(
      'default hook' => 'default_og_membership_type',
    ),
    'bundle of' => 'og_membership',
    'module' => 'og',
    'metadata controller class' => 'EntityDefaultMetadataController',
    'views controller class' => 'EntityDefaultViewsController',
    'access callback' => 'og_membership_type_access',
    'entity cache' => module_exists('entitycache'),
  );

  if (class_exists('OgMembershipTypeUIController')) {
    $items['og_membership_type'] += array(
      // Enable the entity API's admin UI.
      'admin ui' => array(
        // TODO: This path doesn't exist before OG-ui.
        'path' => 'admin/config/group/group-membership',
        'file' => 'includes/og.admin.inc',
        'controller class' => 'OgMembershipTypeUIController',
      ),
    );
  }

  $items['og_membership'] = array(
    'label' => t('OG membership'),
    'entity class' => 'OgMembership',
    'controller class' => 'EntityAPIController',
    'base table' => 'og_membership',
    'fieldable' => TRUE,
    'entity keys' => array(
      'id' => 'id',
      // The message has no label.
      'label' => FALSE,
      'bundle' => 'type',
    ),
    'label callback' => 'og_membership_label',
    'bundles' => array(),
    'bundle keys' => array(
      'bundle' => 'name',
    ),
    'module' => 'og',
    'metadata controller class' => 'OgMembershipMetadataController',
    'views controller class' => 'OgMembershipViewsController',
    'access callback' => 'og_membership_access',
    'entity cache' => module_exists('entitycache'),
  );

  // Add bundle info but bypass entity_load() as we cannot use it here.
  if (db_table_exists('og_membership_type')) {
    $memberships = db_select('og_membership_type', 'g')
      ->fields('g')
      ->execute()
      ->fetchAllAssoc('name');

    foreach ($memberships as $type_name => $type) {
      $items['og_membership']['bundles'][$type_name] = array(
        'label' => $type->name,
        'admin' => array(
          'path' => 'admin/config/group/group-membership/manage/%og_membership_type',
          'real path' => 'admin/config/group/group-membership/manage/' . $type->name,
          'bundle argument' => 5,
          'access arguments' => array('administer group'),
        ),
      );
    }
  }

  return $items;
}

/**
 * Implements hook_entity_property_info().
 */
function og_entity_property_info() {
  $info = array();

  // Add OG membership metadata for every bundle that is a group content.
  foreach (og_get_all_group_content_bundle() as $entity_type => $bundles) {
    foreach ($bundles as $bundle => $bundle_value) {
      $info[$entity_type]['bundles'][$bundle]['properties']['og_membership'] = array(
        'label' => t("OG memberships"),
        'type' => 'list<og_membership>',
        'description' => t("A list of all OG memberships of the @name entity.", array('@name' => $entity_type)),
        'getter callback' => 'og_get_og_membership_properties',
      );

      // Add per-state properties.
      $general = $info[$entity_type]['bundles'][$bundle]['properties']['og_membership'];
      foreach (og_group_content_states() as $state => $state_label) {
        $params = array('@state' => $state_label, '@name' => $entity_type);
        $info[$entity_type]['bundles'][$bundle]['properties']['og_membership__' . $state] = $general;
        $info[$entity_type]['bundles'][$bundle]['properties']['og_membership__' . $state]['label'] = t('@state OG membership', $params);
        $info[$entity_type]['bundles'][$bundle]['properties']['og_membership__' . $state]['description'] = t("A list of all OG memberships of the @name entity with @state state.", $params);
      }

      // Add OG membership per field in a bundle.
      foreach (og_get_group_audience_fields($entity_type, $bundle) as $field_name => $label) {
        $params = array('@label' => $label);
        $field_info = field_info_field($field_name);
        $group_type = $field_info['settings']['target_type'];
        $info[$entity_type]['bundles'][$bundle]['properties'][$field_name . '__og_membership'] = array(
          'label' => t('OG membership from field @label', $params),
          'type' => 'list<og_membership>',
          // The bundle in this context means the OG membership type.
          'bundle' => $field_info['settings']['handler_settings']['membership_type'],
          'description' => t('A list of all OG memberships registered in field @label.', $params),
          'getter callback' => 'og_get_field_og_membership_properties',
        );


        // Add per-state properties.
        $general = $info[$entity_type]['bundles'][$bundle]['properties'][$field_name . '__og_membership'];
        foreach (og_group_content_states() as $state => $state_label) {
          $params = array(
            '@label' => $label,
            '@label' => $label,
            '@state' => $state_label,
          );
          $info[$entity_type]['bundles'][$bundle]['properties'][$field_name . '__og_membership__' . $state] = $general;
          $info[$entity_type]['bundles'][$bundle]['properties'][$field_name . '__og_membership__' . $state]['label'] = t('@state OG memberships from field @label', $params);
          $info[$entity_type]['bundles'][$bundle]['properties'][$field_name . '__og_membership__' . $state]['description'] = t('A list of all OG memberships with @state registered in field @label.', $params);
        }
      }
    }
  }

  foreach (og_get_all_group_bundle() as $entity_type => $bundles) {
    foreach ($bundles as $bundle => $bundle_value) {
      $info[$entity_type]['bundles'][$bundle]['properties']['members'] = array(
          'label' => t("Group members"),
          'type' => 'list<user>',
          'description' => t("A list group members of the @name entity.", array('@name' => $entity_type)),
          'getter callback' => 'og_get_group_members_properties',
        );

        // Add per-state properties.
        $general = $info[$entity_type]['bundles'][$bundle]['properties']['members'];
        foreach (og_group_content_states() as $state => $state_label) {
          $params = array('@state' => $state_label, '@name' => $entity_type);
          $info[$entity_type]['bundles'][$bundle]['properties']['members__' . $state] = $general;
          $info[$entity_type]['bundles'][$bundle]['properties']['members__' . $state]['label'] = t('@state group members', $params);
          $info[$entity_type]['bundles'][$bundle]['properties']['members__' . $state]['description'] = t("A list of all users of the @name entity with @state state.", $params);
        }
    }
  }

  return $info;
}

/**
 * Property getter callback for group members.
 *
 * @see og_entity_property_info()
 */
function og_get_group_members_properties($entity, array $options, $name, $type) {
  $args = explode('__', $name);
  $state = !empty($args[1]) ? $args[1] : FALSE;
  list($id) = entity_extract_ids($type, $entity);

  $cache = &drupal_static(__FUNCTION__, array());
  if (isset($cache[$type][$id][$state])) {
    // Return the cached result.
    return $cache[$type][$id][$state];
  }
  $cache[$type][$id][$state] = array();

  $query = new EntityFieldQuery();
  $query
    ->entityCondition('entity_type', 'og_membership')
    ->propertyCondition('group_type', $type, '=')
    ->propertyCondition('gid', $id, '=')
    ->propertyCondition('entity_type', 'user', '=');

  if ($state) {
    $query->propertyCondition('state', $state, '=');
  }

  $result = $query->execute();
  if (!empty($result['og_membership'])) {
    $og_memberships = og_membership_load_multiple(array_keys($result['og_membership']));
    foreach ($og_memberships as $og_membership) {
      $cache[$type][$id][$state][] = $og_membership->etid;

    }
  }
  return $cache[$type][$id][$state];
}

/**
 * Property getter callback for OG membership.
 *
 * @see og_entity_property_info()
 */
function og_get_og_membership_properties($entity, array $options, $name, $type) {
  // Get the state from name, if exists.
  if ($name == 'og_membership') {
    $state = array();
  }
  else {
    $args = explode('__', $name);
    $state = array($args[1]);
  }

  $ids = array();

  if ($gids = og_get_entity_groups($type, $entity, $state)) {
    $ids = array();
    foreach ($gids as $group_type => $values) {
      $ids = array_merge($ids, array_keys($values));
    }
  }

  return $ids;
}

/**
 * Property getter callback for OG membership per field.
 *
 * @see og_entity_property_info()
 */
function og_get_field_og_membership_properties($entity, array $options, $name, $type) {
  $args = explode('__', $name);
  // Field name might have double underscore as-well, so we need to make
  // sure we get it right.
  $last_char = substr($name, -1);
  $state = is_numeric($last_char) ? $last_char : FALSE;

  // The number of characters to ignore in the name (i.e. remove the
  // "__og_membership" or "__og_membership__0").
  $remove_char = $state ? -18 : -15;
  $field_name = substr($name, 0, $remove_char);

  $field_name = $args[0];
  $field = field_info_field($field_name);
  $states = count($args) == 2 ? FALSE : array($args[2]);

  $result = og_get_entity_groups($type, $entity, $states, $field_name);
  $target_type = $field['settings']['target_type'];

  return !empty($result[$target_type]) ? array_keys($result[$target_type]) : array();
}

/**
 * Getter callback to load the 'entity' or 'group' property from OG membership.
 *
 * We have to return the entity wrapped.
 */
function og_entity_getter($object, array $options, $property_name) {
  switch ($property_name) {
    case 'entity':
      return entity_metadata_wrapper($object->entity_type, $object->etid);
    case 'group':
      return entity_metadata_wrapper($object->group_type, $object->gid);
  }
}

/**
 * Entity property info setter callback to set the "entity" property for groups
 * and memberships.
 *
 * As the property is of type entity, the value will be passed as a wrapped
 * entity.
 */
function og_entity_setter($object, $property_name, $wrapper) {
  switch ($property_name) {
    case 'entity':
      $object->entity_type = $wrapper->type();
      $object->etid = $wrapper->getIdentifier();
      break;
    case 'group':
      $object->group_type = $wrapper->type();
      $object->gid = $wrapper->getIdentifier();
      break;
  }
}

/**
 * Implements hook_default_og_membership_type().
 */
function og_default_og_membership_type() {
  $items = array();
  $items['og_membership_type_default'] = entity_import('og_membership_type', '{
    "name" : "og_membership_type_default",
    "description" : "Default",
    "rdf_mapping" : []
  }');
  return $items;
}

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

/**
 * Implements hook_ctools_plugin_directory().
 */
function og_ctools_plugin_directory($module, $plugin) {
  if ($module == 'ctools') {
    return 'plugins/' . $plugin;
  }
  elseif ($module == 'entityreference') {
    return "plugins/entityreference/$plugin";
  }
}

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

/**
 * Implements 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 group members and content in the group.'),
    'default role' => array(OG_ADMINISTRATOR_ROLE),
    'restrict access' => TRUE,
  );

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

  return $perms;
}


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

/**
 * Implements hook_node_access().
 */
function og_node_access($node, $op, $account) {
  $type = is_string($node) ? $node : (is_array($node) ? $node['type'] : $node->type);

  if ($op == 'create' && og_is_group_content_type('node', $type)) {
    // Save some legwork if the user has the core permission and strict node
    // access is not set.
    if (!variable_get('og_node_access_strict', TRUE) && user_access("create $type content", $account)) {
      // We just ignore: core access will take care of it.
      return NODE_ACCESS_IGNORE;
    }

    if (user_access('administer group', $account)) {
      return NODE_ACCESS_ALLOW;
    }
    // We can't check if user has create permissions using og_user_access(), as
    // there is no group context. However, we can check if there are any groups
    // the user will be able to select, and if not, we don't allow access.
    // @see OgSelectionHandler::getReferencableEntities()
    $required = FALSE;
    foreach (og_get_group_audience_fields('node', $type) as $field_name => $label) {
      $field = field_info_field($field_name);
      $instance = field_info_instance('node', $field_name, $type);
      // Set the "field mode" to default, before passing it to the
      // selection handler.
      $instance['field_mode'] = 'default';
      if (entityreference_get_selection_handler($field, $instance)->countReferencableEntities()) {
        return NODE_ACCESS_ALLOW;
      }

      // Allow users to create content outside of groups, if none of the
      // audience fields is required.
      if ($instance['required']) {
        $required = TRUE;
      }
    }
    // If no group audience field is required, we ignore.
    if (!$required) {
      return NODE_ACCESS_IGNORE;
    }

    // Otherwise, ignore or deny based on whether strict node access is set.
    return variable_get('og_node_access_strict', TRUE) ? NODE_ACCESS_DENY : NODE_ACCESS_IGNORE;
  }
  elseif (in_array($op, array('update', 'delete'))) {
    $access = og_user_access_entity('administer group', 'node', $node, $account);

    if (is_null($access)) {
      // The node isn't in an OG context, so no need to keep testing.
      return NODE_ACCESS_IGNORE;
    }
    else {
      $access = $access ||
        // Any content.
        og_user_access_entity("$op any $type content", 'node', $node, $account) ||
        // Own content.
        ($account->uid == $node->uid && og_user_access_entity("$op own $type content", 'node', $node, $account));
    }

    if (!$access && $op == 'update' && og_is_group('node', $node)) {
      // The node is a group, so check "update group" permission.
      $access = og_user_access_entity('update group', 'node', $node, $account);
    }

    if ($access) {
      return NODE_ACCESS_ALLOW;
    }

    // Check if OG should explicitly deny access or not.
    return variable_get('og_node_access_strict', TRUE) ? NODE_ACCESS_DENY : NODE_ACCESS_IGNORE;
  }

  return NODE_ACCESS_IGNORE;
}

/**
 * Implements hook_field_access().
 *
 * Hide group-audience fields from user's edit profile for non-privileged users.
 */
function og_field_access($op, $field, $entity_type, $entity, $account) {
  global $user;

  if (empty($entity)) {
    // We are in field settings page.
    return;
  }


  if (!$user->uid) {
    // User is anonymous, and user register might try to add the
    // group-audience field.
    return;
  }

  if ($op != 'edit') {
    return;
  }

  $field_name = $field['field_name'];
  list($id, $vid, $bundle_name) = entity_extract_ids($entity_type, $entity);
  $instance = field_info_instance($entity_type, $field_name, $bundle_name);
  if ($field_name == OG_GROUP_FIELD) {
    $wrapper = entity_metadata_wrapper($entity_type, $entity);
    if ($wrapper->getIdentifier() && !$wrapper->{OG_GROUP_FIELD}->value()) {
      // Entity isn't an active group.
      return;
    }
    if (!empty($instance['widget']['settings']['og_hide'])) {
      return FALSE;
    }
    return;
  }

  if (!og_is_group_audience_field($field_name)) {
    return;
  }

  $field = field_info_field($field_name);
  $settings = $field['settings']['handler_settings'];

  // Check if we are editing the user entity.
  if ($entity_type == 'user') {
    if (!empty($instance['settings']['behaviors']['og_widget']['access_override'])) {
      return;
    }

    return user_access('administer group', $account);
  }
}


/**
 * Implements hook_views_api().
 */
function og_views_api() {
  return array(
    'api' => 3,
    'path' => drupal_get_path('module', 'og') . '/includes/views',
  );
}


/**
 * Implements hook_field_create_instance().
 *
 * - Create default OG roles per entity-type and bundle.
 * - Create a group audience field on the user's entity, referencing the first
 *   group defined.
 */
function og_field_create_instance($instance) {
  if ($instance['field_name'] != OG_GROUP_FIELD) {
    return;
  }

  // Create default roles per entity-type per bundle.
  og_roles_override($instance['entity_type'], $instance['bundle'], 0);

  // Check if we need to add a group audience on the user's entity.
  // We add a different field, so each field can be set differently.
  $entity_type = $instance['entity_type'];
  $bundle = $instance['bundle'];
  foreach (array_keys(og_get_group_audience_fields()) as $field_name) {
    $field = field_info_field($field_name);

    if ($field['settings']['target_type'] == $entity_type  && empty($field['settings']['handler_settings']['target_bundles'])) {
      return;
    }

    if ($field['settings']['target_type'] == $entity_type && in_array($bundle, $field['settings']['handler_settings']['target_bundles'])) {
      return;
    }
  }

  // If we reached here, it means we need to create a field.
  // Pick an unused name.
  $field_name = substr("og_user_$entity_type", 0, 32);
  $i = 1;
  while (field_info_field($field_name)) {
    $field_name = substr("og_user_$entity_type", 0, 32 - strlen($i)) . $i;
    ++$i;
  }

  $og_field = og_fields_info(OG_AUDIENCE_FIELD);
  $og_field['field']['settings']['target_type'] = $entity_type;
  $og_field['instance']['label'] = t('Group membership');

  // If the user entity type has multiple bundles, make sure to attach a field
  // instance to all of them.
  $entity_info = entity_get_info('user');
  foreach (array_keys($entity_info['bundles']) as $user_bundle) {
    og_create_field($field_name, 'user', $user_bundle, $og_field);
  }
}

/**
 * Implements field_delete_instance().
 *
 * - Invalidate OG's static cache if a group-audience field is deleted.
 * - Delete the default OG roles per entity-type and bundle.
 */
function og_field_delete_instance($instance) {
  if (og_is_group_audience_field($instance['field_name'])) {
    og_invalidate_cache();
  }

  if ($instance['field_name'] != OG_GROUP_FIELD) {
    return;
  }

  // Get the per-bundle roles.
  $roles = og_roles($instance['entity_type'], $instance['bundle']);
  foreach ($roles as $rid => $name) {
    og_role_delete($rid);
  }
}

/**
 * Implements hook_field_attach_form().
 */
function og_field_attach_form($entity_type, $entity, &$form, &$form_state, $langcode) {
  list(,, $bundle) = entity_extract_ids($entity_type, $entity);

  if (og_get_group_audience_fields($entity_type, $bundle)) {
    $form['#validate'][] = 'og_form_group_reference_validate';
  }

  if ($entity_type == 'user' || !og_is_group_type($entity_type, $bundle)) {
    return;
  }
  $form['#validate'][] = 'og_form_group_manager_validate';
}

/**
 * Validate handler; Make sure group-only content permissions are honored.
 *
 * If a user does not have site-wide node permissions, throw an error if they
 * try to post site-wide instead of within a group.
 *
 * Note: This function does not check group -access- just if a group has been
 * Selected.
 */
function og_form_group_reference_validate($form, &$form_state) {
  global $user;
  $entity_type = $form['#entity_type'];
  if (empty($form_state[$entity_type])) {
    // We are inside field settings page.
    return;
  }

  $account = user_load($user->uid);
  $bundle = $form['#bundle'];
  $entity = $form['#entity'];
  list($id) = entity_extract_ids($entity_type, $entity);

  $op = empty($id) ? 'create' : 'update';

  if ($entity_type == 'node') {
    $node = empty($id) ? $bundle : $entity;
    // We call node_node_access() directly as we just want to check the
    // permissions using user_acces().
    if (node_node_access($node, $op, $account)) {
      // User has site-wide permissions to create or edit the node.
      return;
    }
  }
  elseif (entity_access($op, $entity_type, $entity, $account)) {
    // User has site-wide permissions to create or edit the entity.
    return;
  }

  foreach (array_keys(og_get_group_audience_fields($entity_type, $bundle)) as $field_name) {
    // If there is at least one group selected, return.
    if (!empty($form_state['values'][$field_name][LANGUAGE_NONE])) {
      return;
    }
  }

  // No group selected, throw an error.
  form_set_error('og', t('You must select one or more groups for this content.'));
}

/**
 * Validate handler; Make sure a group can be created.
 *
 * We check if the group manager has a matching group-audience field for the
 * OG membership to be created in.
 */
function og_form_group_manager_validate($form, &$form_state) {
  $entity_type = $form['#entity_type'];
  $bundle = $form['#bundle'];
  if (empty($form_state[$entity_type])) {
    // We are inside field settings page.
    return;
  }
  $entity = $form_state[$entity_type];
  $langcode = $form_state['values']['language'];

  if (!isset($form_state['values']['uid']) || !isset($entity->uid)) {
    // There is no user ID property on the entity.
    return;
  }

  if (isset($form_state['values'][OG_GROUP_FIELD]) && empty($form_state['values'][OG_GROUP_FIELD][$langcode][0]['value'])) {
    // Not a group.
    return;
  }

  if (!isset($form_state['values'][OG_GROUP_FIELD])) {
    // Field doesn't appear in the form, so it is probably hidden by
    // hook_field_access(). So check the default value of the field.
    $field = field_info_field(OG_GROUP_FIELD);
    $instance = field_info_instance($entity_type, OG_GROUP_FIELD, $bundle);

    $items = field_get_default_value($entity_type, $entity, $field, $instance, $langcode);
    if (empty($items[0]['value'])) {
      // Default value is not a group.
      return;
    }
  }

  if ($entity_type == 'node') {
    // A user might assign the node author by entering a user name in the
    // node form, which we then need to translate to a user ID.
    // However, this happens later on, in node_submit(), so we do a special
    // check for the node entity.
    if (!$account = user_load_by_name($form_state['values']['name'])) {
      // Invalid username.
      return;
    }
  }
  else {
    $account = user_load($form_state['values']['uid']);
  }

  list($id) = entity_extract_ids($entity_type, $entity);

  if ($id && $entity->uid == $account->uid) {
    // The entity's user ID hasn't changed.
    return;
  }

  if ($access = og_get_best_group_audience_field('user', $account, $entity_type, $bundle)) {
    // Matching group audience field found.
    return;
  }

  form_error($form, t("Can't save entity as group, because user @name can't be subscribed to group and become a manager.", array('@name' => format_username($account))));
}

/**
 * Implements hook_entity_insert().
 */
function og_entity_insert($entity, $entity_type) {
  if (!og_is_group($entity_type, $entity)) {
    return;
  }
  list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);
  if (!empty($entity->uid)) {
    // Subscribe the group manager.
    og_group($entity_type, $id, array('entity' => $entity->uid));
    // Assign roles to group manager.
    $name = 'og_group_manager_default_rids_' . $entity_type . '_' . $bundle;
    if ($rids = variable_get($name)) {
      foreach ($rids as $rid) {
        og_role_grant($entity_type, $id, $entity->uid, $rid);
      }
    }
  }
  if (!og_is_group_default_access($entity_type, $entity)) {
    // Override default roles.
    og_roles_override($entity_type, $bundle, $id);
  }
}

/**
 * Implements hook_entity_update().
 */
function og_entity_update($entity, $entity_type) {
  if (!og_is_group($entity_type, $entity)) {
    return;
  }

  list($id, , $bundle) = entity_extract_ids($entity_type, $entity);
  if (!empty($entity->uid) && !og_is_member($entity_type, $entity, 'user', $entity->uid)) {
    // Subscribe the group manager, in case the owner changed.
    og_group($entity_type, $id, array('entity' => $entity->uid));
    // Assign roles to group manager.
    $name = 'og_group_manager_default_rids_' . $entity_type . '_' . $bundle;
    if ($rids = variable_get($name)) {
      foreach ($rids as $rid) {
        og_role_grant($entity_type, $id, $entity->uid, $rid);
      }
    }
  }
  $original_entity = $entity->original;
  $property = OG_DEFAULT_ACCESS_FIELD;

  if (!empty($entity->{$property}) && $entity->{$property} != $original_entity->{$property}) {
    if (!og_is_group_default_access($entity_type, $entity)) {
      // Override default roles.
      og_roles_override($entity_type, $bundle, $id);
    }
    else {
      // Delete overridden roles.
      og_delete_user_roles_by_group($entity_type, $entity);
    }
  }
}

/**
 * Implements hook_field_attach_insert().
 */
function og_field_attach_insert($entity_type, $entity) {
  _og_update_entity_fields($entity_type, $entity);
}

/**
 * Implements hook_field_attach_update().
 */
function og_field_attach_update($entity_type, $entity) {
  _og_update_entity_fields($entity_type, $entity);
}

/**
 * Update the field values in the entity, to reflect the membership.
 *
 * This is used to allow other modules that save a new/ existing entity
 * to act on the field values, even before hook_field_load() is called.
 */
function _og_update_entity_fields($entity_type, $entity) {
  list($id, $vid, $bundle) = entity_extract_ids($entity_type, $entity);
  if (!og_is_group_content_type($entity_type, $bundle)) {
    return;
  }

  $wrapper = entity_metadata_wrapper($entity_type, $entity);
  foreach (og_get_group_audience_fields($entity_type, $bundle) as $field_name => $label) {
    $field = field_info_field($field_name);
    $gids = array();
    if ($field['cardinality'] == 1) {
      if ($og_membership = $wrapper->{$field_name . '__og_membership'}->value()) {
        // Wrapper return an array.
        $gids = $og_membership[0]->gid;
      }
    }
    else {
      $target_type = $field['settings']['target_type'];
      $gids = og_get_entity_groups($entity_type, $entity, array(), $field_name);
      $gids = !empty($gids[$target_type]) ? array_values($gids[$target_type]) : array();
    }
    if ($gids) {
      $wrapper->{$field_name}->set($gids);
    }
  }
}


/**
 * Implements hook_entity_delete().
 */
function og_entity_delete($entity, $entity_type) {
  list($id, , $bundle) = entity_extract_ids($entity_type, $entity);
  if (og_is_group($entity_type, $entity)) {
    og_delete_user_roles_by_group($entity_type, $entity);
    og_membership_delete_by_group($entity_type, $entity);
  }
  if (og_is_group_content_type($entity_type, $bundle)) {
    // As the field attachers are called after hook_entity_presave() we
    // can't delete the OG memberships here. So we just mark the entity
    // as being deleted, and we will do the actual delete in
    // OgBehaviorHandler::delete().
    $entity->delete_og_membership = TRUE;
  }
}

/**
 * Implements hook_og_membership_insert().
 */
function og_og_membership_insert($og_membership) {
  if ($og_membership->entity_type == 'user' && module_exists('rules')) {
    rules_invoke_event('og_user_insert', $og_membership, entity_metadata_wrapper('user', $og_membership->etid));
  }
}

/**
 * Implements hook_og_membership_update().
 */
function og_og_membership_update($og_membership) {
  if ($og_membership->entity_type == 'user' && module_exists('rules')) {
    if ($og_membership->original->state != OG_STATE_ACTIVE && $og_membership->state == OG_STATE_ACTIVE) {
      rules_invoke_event('og_user_approved', $og_membership, entity_metadata_wrapper('user', $og_membership->etid));
    }
    if ($og_membership->original->state != OG_STATE_BLOCKED && $og_membership->state == OG_STATE_BLOCKED) {
      rules_invoke_event('og_user_blocked', $og_membership, entity_metadata_wrapper('user', $og_membership->etid));
    }
  }
}

/**
 * Implements hook_og_membership_delete().
 */
function og_og_membership_delete($og_membership) {
  if ($og_membership->entity_type != 'user')  {
    return;
  }

  // Remove possible records in the {og_users_roles} table.
  db_delete('og_users_roles')
    ->condition('uid', $og_membership->etid)
    ->condition('gid', $og_membership->gid)
    ->condition('group_type', $og_membership->group_type)
    ->execute();

  if (module_exists('rules'))  {
    rules_invoke_event('og_user_delete', $og_membership, entity_metadata_wrapper('user', $og_membership->etid));
  }
}

/**
 * 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,
      'type' => 'list_boolean',
      'cardinality' => 1,
      'settings' => array(
        'allowed_values' => array(0 => 'Not a group', 1 => 'Group'),
        'allowed_values_function' => '',
      ),
    ),
    'instance' => array(
      'label' => t('Group'),
      'description' => t('Determine if this is an OG group.'),
      'display_label' => 1,
      'widget' => array(
        'module' => 'options',
        'settings' => array(
          'og_hide' => TRUE,
        ),
        'type' => 'options_onoff',
        'weight' => 0,
      ),
      '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,
      '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' => array(
        'module' => 'options',
        'settings' => array(),
        '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(
    'multiple' => TRUE,
    'type' => array('group content'),
    'description' => t('Determine to which groups this group content is assigned to.'),
    'field' => array(
      'field_name' => OG_AUDIENCE_FIELD,
      'type' => 'entityreference',
      'cardinality' => FIELD_CARDINALITY_UNLIMITED,
      'settings' => array(
        'handler' => 'og',
        'handler_submit' => 'Change handler',
        'handler_settings' => array(
          'behaviors' => array(
            'og_behavior' => array(
              'status' => TRUE,
            ),
          ),
          'target_bundles' => array(),
          'membership_type' => OG_MEMBERSHIP_TYPE_DEFAULT,
        ),
        'target_type' => 'node',
      ),
    ),
    'instance' => array(
      'label' => t('Groups audience'),
      'widget' => array(
        'type' => 'og_complex',
        'module' => 'og',
        'settings' => array(),
      ),
      'settings' => array(
        'behaviors' => array(
          'og_widget' => array(
            'status' => TRUE,
            'default' => array(
              'widget_type' => 'options_select',
            ),
            'admin' => array(
              'widget_type' => 'entityreference_autocomplete',
            ),
          ),
        ),
      ),
      '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;
}

/**
 * Creates a new membership type.
 *
 * If a message type already exists, an exception will be thrown.
 *
 * @return OgMembershipType
 *   Returns a new OG membership type object.
 */
function og_membership_type_create($name, $values = array()) {
  global $language;
  // Make sure the message type doesn't already exist, to prevent duplicate key
  // error.
  if (og_membership_type_load($name)) {
    throw new OgException('Group membership type ' . check_plain($name) . ' already exists.');
  }
  $values['name'] = $name;
  $values += array(
    'language' => $language->language,
  );
  $wrapper = entity_property_values_create_entity('og_membership_type', $values);
  return $wrapper->value();
}

/**
 * OG membership type loader.
 *
 * @param $type_name
 *   (optional) The name for this message type. If no type is given all existing
 *   types are returned.
 *
 * @return MessageType
 *   Returns a fully-loaded message type definition if a type name is passed.
 *   Else an array containing all types is returned.
 */
function og_membership_type_load($name = NULL) {
  // Replace dashes with underscores so this can be used as menu argument
  // loader too.
  $types = entity_load_multiple_by_name('og_membership_type', isset($name) ? array(strtr($name, array('-' => '_'))) : FALSE);
  if (isset($name)) {
    return isset($types[$name]) ? $types[$name] : FALSE;
  }
  return $types;
}

/**
 * Inserts or updates an OG membership type entity into the database.
 *
 * @param $og_membership
 *   The OG membership type entiyt to be saved.
 *
 * @return
 *   Failure to write a record will return FALSE. Otherwise SAVED_NEW or
 *   SAVED_UPDATED is returned depending on the operation performed.
 */
function og_membership_type_save($og_membership) {
  return entity_save('og_membership_type', $og_membership);
}

/**
 * Deletes an existing OG membership type.
 *
 * @param $og_membership
 *   The OG membership type entity to be deleted.
 */
function og_membership_type_delete($og_membership) {
  return entity_delete('og_membership_type', $og_membership);
}

/**
 * Access callback for the OG membership type entity.
 */
function og_membership_type_access($op, $entity, $account = NULL, $entity_type = 'og_membership') {
  // No-end user needs access to this entity, so restrict it to admins.
  return user_access('administer group');
}

/**
 * Reset static cache related to group membership.
 *
 * @deprecated
 *   Use og_invalidate_cache() instead.
 */
function og_membership_invalidate_cache() {
  og_invalidate_cache();
}

/**
 * Creates a new OG membership.
 *
 * If a group membership already exists, an exception will be thrown.
 *
 * @param $group_type
 *   The entity type of the group.
 * @param $gid
 *   The group ID.
 * @param $entity_type
 *   The entity type of the group content.
 * @param $etid
 *   The entity ID of the group content.
 * @param $field_name
 *   The group audience field name.
 * @param $values
 *   (optional) Array of fields values to be attached to the OG membership, that
 *   will be processed using entity-metadata wrapper.
 *
 * @return OgMembership
 *   Returns a new OG membership object.
 *
 * @see entity_property_values_create_entity()
 */
function og_membership_create($group_type, $gid, $entity_type, $etid, $field_name, $values = array()) {
  global $language;

  $values += array(
    'group_type' => $group_type,
    'gid' => $gid,
    'entity_type' => $entity_type,
    'etid' => $etid,
    'state' => OG_STATE_ACTIVE,
    'created' => time(),
    'field_name' => $field_name,
    'language' => $language->language,
  );

  if (!og_is_group_audience_field($field_name)) {
    throw new OgException(format_string('%field-name is not a valid group-audience field.', array('%field-name' => $field_name)));
  }

  // Get the type from the field.
  $field = field_info_field($field_name);
  $values['type'] = $field['settings']['handler_settings']['membership_type'];

  $wrapper = entity_property_values_create_entity('og_membership', $values);
  return $wrapper->value();
}

/**
 * OG membership loader.
 *
 * @param $name
 *   (optional) The name for this group membership. If no type is given all existing
 *   types are returned.
 *
 * @return OgMembership
 *   Returns a fully-loaded group membership definition if a type name is passed.
 *   Else an array containing all types is returned.
 */
function og_membership_load($id) {
  return entity_load_single('og_membership', $id);
}

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

/**
 * Get the group membership entity by user and group.
 *
 * @return
 *   The OgMembership object if found, or FALSE.
 */
function og_get_membership($group_type, $gid, $entity_type, $etid) {
  $return = &drupal_static(__FUNCTION__, array());
  $identifier = $group_type . ':' . $gid . ':' . $entity_type . ':' . $etid;
  if (!isset($return[$identifier])) {
    $return[$identifier] = FALSE;

    $query = new EntityFieldQuery();
    $result = $query
      ->entityCondition('entity_type', 'og_membership')
      ->propertyCondition('gid', $gid, '=')
      ->propertyCondition('group_type', $group_type, '=')
      ->propertyCondition('etid', $etid, '=')
      ->propertyCondition('entity_type', $entity_type, '=')
      ->execute();

    if (!empty($result['og_membership'])) {
      $key = key($result['og_membership']);
      $return[$identifier] = $key;
    }
  }

  if (!empty($return[$identifier])) {
    $og_membership = og_membership_load($return[$identifier]);
    return $og_membership;
  }
  return FALSE;
}

/**
 * Implements hook_entity_query_alter().
 *
 * Add "og_membership" tag if there's a group audience field in the query.
 *
 * @see og_query_og_membership_alter().
 */
function og_entity_query_alter(EntityFieldQuery $query) {
  foreach ($query->fieldConditions as $values) {
    if (og_is_group_audience_field($values['field']['field_name'])) {
      $query->addTag('og_membership');
      return;
    }
  }
}

/**
 * Implements hook_query_TAG_alter().
 *
 * Join the {og_membership} table and alter the query.
 */
function og_query_og_membership_alter(QueryAlterableInterface $query) {
  $tables = &$query->getTables();
  $fields = &$query->getFields();
  $conditions = &$query->conditions();

  // Find the group-audience fields.
  $field_names = array();
  foreach ($query->alterMetaData['entity_field_query']->fieldConditions as $values) {
    $field_name = $values['field']['field_name'];
    if (og_is_group_audience_field($field_name)) {
      $field_names[] = $field_name;
    }
  }

  $aliases = array();
  $base_table = FALSE;
  $base_table_alias = '';

  foreach ($tables as $alias => $values) {
    if (!$base_table_alias && empty($values['join type'])) {
      $base_table_alias = $alias;
    }

    if (strpos($alias, 'field_data') !== 0) {
      continue;
    }
    $field_name = substr($values['table'], 11);
    if (!in_array($field_name, $field_names)) {
      continue;
    }

    if (empty($values['join type'])) {
      // This is the base table, so remove it in favor of OG membership.
      $base_table = TRUE;
    }

    unset($tables[$alias]);
    $aliases[$alias] = $field_name;
  }

  foreach ($aliases as $alias => $field_name) {
    foreach ($tables as $key => $values) {
      $condition = str_replace("$alias.entity_type", 'ogm.entity_type', $values['condition']);
      $condition = str_replace("$alias.entity_id", 'ogm.etid', $condition);
      $tables[$key]['condition'] = $condition;
    }
  }

  $entity_type = $query->alterMetaData['entity_field_query']->entityConditions['entity_type']['value'];
  $entity_type = is_array($entity_type) ? $entity_type[0] : $entity_type;
  $entity_info = entity_get_info($entity_type);
  $id = $entity_info['entity keys']['id'];

  if ($base_table) {
    // If the table of the base entity does not exist (e.g. there is no
    // property condition), we need to add it, as we don't have the
    // revision ID and bundle in {og_membership} table.
    $base_table = $entity_info['base table'];
    if (strpos($base_table_alias, 'field_data') === 0) {
      // Check if the entity base table already exists.
      $base_table_alias = FALSE;
      foreach ($tables as $table) {
        if ($table['table'] == $base_table) {
          $base_table_alias = $table['alias'];
          break;
        }
      }
      if (!$base_table_alias) {
        $base_table_alias = $query->innerJoin($base_table, NULL, "$base_table.$id = ogm.etid");
      }
    }

    // Point the revision ID and bundle to the base entity.
    $fields['revision_id']['table'] = $base_table;
    // If there is no revision table, use the bundle.
    if (!empty($entity_info['entity keys']['revision'])) {
      // Entity doesn't support revisions.
      $fields['revision_id']['field'] = $entity_info['entity keys']['revision'];

    }
    elseif (!empty($entity_info['entity keys']['bundle'])) {
      $fields['revision_id']['field'] = $entity_info['entity keys']['bundle'];

    }
    else {
      // Entity doesn't have bundles (e.g. user).
      $fields['revision_id']['field'] = $id;
    }

    $fields['bundle']['table'] = $base_table;
    $fields['bundle']['field'] = !empty($entity_info['entity keys']['bundle']) ? $entity_info['entity keys']['bundle'] : $id;
    $fields['entity_type']['table'] = 'ogm';
    $fields['entity_type']['field'] = 'entity_type';
    $fields['entity_id']['table'] = 'ogm';
    $fields['entity_id']['field'] = 'etid';

    // Populate the alias key, as it might be empty on COUNT queries.
    foreach (array_keys($fields) as $key) {
      if (empty($fields[$key]['alias'])) {
        $fields[$key]['alias'] = $key;
      }
    }

    $ogm = array(
      'join type' => NULL,
      'table' => 'og_membership',
      'alias' => 'ogm',
      'condition' => '',
      'arguments' => array(),
    );

    $tables = array_merge(array('ogm' => $ogm), $tables);
  }
  else {
    // If the original EntityFieldQuery has an entity type entityCondition,
    // restrict the join by this. Otherwise, we would bring in the IDs of
    // entities of other types if they happen to match on the base table entity
    // ID.
    $query_base_entity_type = $query->alterMetaData['entity_field_query']->entityConditions['entity_type']['value'];
    if (empty($query_base_entity_type)) {
      // It's possible to have no entity type specified: join without it.
      $query->join('og_membership', 'ogm', "ogm.etid = $base_table_alias.entity_id");
    }
    else {
      if (is_array($query_base_entity_type)) {
        // It's also possible for the entity type to be multiple.
        $query->join('og_membership', 'ogm', "ogm.etid = $base_table_alias.entity_id AND ogm.entity_type IN (:entity_type)", array(
          ':entity_type' => $query_base_entity_type,
        ));
      }
      else {
        $query->join('og_membership', 'ogm', "ogm.etid = $base_table_alias.entity_id AND ogm.entity_type = :entity_type", array(
          ':entity_type' => $query_base_entity_type,
        ));
      }
    }
  }

  _og_query_og_membership_alter_conditions($conditions, $aliases, $base_table_alias, $entity_info);
}

/**
 * Recursively replace the fields to their aliases in the query's conditions.
 *
 * See og_query_og_membership_alter().
 */
function _og_query_og_membership_alter_conditions(&$conditions, $aliases, $base_table_alias, $entity_info) {
  foreach ($conditions as $delta => $values) {
    if (!is_array($values)) {
      continue;
    }

    // Handle conditions in a sub-query.
    if (is_object($values['value'])) {
      _og_query_og_membership_alter_conditions($values['value']->conditions(), $aliases, $base_table_alias, $entity_info);
    }

    // Handle sub-conditions.
    if (is_object($values['field'])) {
      _og_query_og_membership_alter_conditions($values['field']->conditions(), $aliases, $base_table_alias, $entity_info);
      continue;
    }

    if (strpos($values['field'], 'field_data_') !== 0) {
      continue;
    }

    // Explode spaces on the fiels, for handling only the first part in values
    // such as "foo.nid = bar.nid".
    $field_parts = explode(' ', $values['field'], 2);
    list($table, $column) = explode('.', $field_parts[0]);

    if (empty($aliases[$table])) {
      continue;
    }
    $table = 'ogm';

    // Replace entity_id or any other primary id (e.g. nid for the node
    // entity).
    $id_columns = array('entity_id', $entity_info['entity keys']['id']);
    if (in_array($column, $id_columns)) {
      $column = 'etid';
    }

    if ($column == 'deleted') {
      unset($conditions[$delta]);
      continue;
    }
    elseif (strpos($column, 'target_id')) {
       $column = 'gid';
    }
    elseif ($column == 'bundle') {
      // Add the bundle of the base entity type.
      $table = $base_table_alias;
      $column = $entity_info['entity keys']['bundle'];
    }

    $conditions[$delta]['field'] = "$table.$column";
    // Add the second part if it exists.
    if (!empty($field_parts[1])) {
      $conditions[$delta]['field'] .= ' ' . $field_parts[1];
    }
  }
}


/**
 * Inserts or updates an OG membership entity into the database.
 *
 * @param $og_membership
 *   The OG membership entity to be inserted.
 *
 * @return
 *   Failure to write a record will return FALSE. Otherwise SAVED_NEW or
 *   SAVED_UPDATED is returned depending on the operation performed.
 */
function og_membership_save($og_membership) {
  return entity_save('og_membership', $og_membership);
}

/**
 * Delete an existing OG membership.
 *
 * @param $id
 *   The OG membership entity ID to be deleted.
 */
function og_membership_delete($id) {
  return og_membership_delete_multiple(array($id));
}

/**
 * Delete multiple existing OG memberships.
 *
 * We can't use entity_delete_multiple(), as we need to make sure the field
 * cache is invalidated.
 *
 * @param $ids
 *   Array with OG membership entity IDs to be deleted.
 */
function og_membership_delete_multiple($ids = array()) {
  entity_delete_multiple('og_membership', $ids);
  og_invalidate_cache();
}

/**
 * Implements hook_cron_queue_info().
 */
function og_cron_queue_info() {
  $items['og_membership_orphans'] = array(
    'title' => t('OG orphans'),
    'worker callback' => 'og_membership_orphans_worker',
    'time' => 60,
  );
  return $items;
}

/**
 * Queue worker; Process a queue item.
 *
 * Delete memberships, and if needed all related group-content.
 */
function og_membership_orphans_worker($data) {
  $group_type = $data['group_type'];
  $gid = $data['gid'];

  $query = new EntityFieldQuery();
  $result = $query
    ->entityCondition('entity_type', 'og_membership')
    ->propertyCondition('group_type', $group_type, '=')
    ->propertyCondition('gid', $gid, '=')
    ->propertyOrderBy('id')
    ->range(0, 50)
    ->execute();

  if (empty($result['og_membership'])) {
    return;
  }

  $ids = array_keys($result['og_membership']);
  if ($data['orphans']['move']) {
    _og_orphans_move($ids, $data['orphans']['move']['group_type'], $data['orphans']['move']['gid']);
    $queue = DrupalQueue::get('og_membership_orphans');
    return $queue->createItem($data);
  }
  elseif ($data['orphans']['delete']) {
    _og_orphans_delete($ids);
    // Create a new item.
    $queue = DrupalQueue::get('og_membership_orphans');
    return $queue->createItem($data);
  }
}

/**
 * Helper function to delete orphan group-content.
 *
 * @param $ids
 *   Array of OG membership IDs.
 *
 * @see og_membership_delete_by_group_worker()
 */
function _og_orphans_delete($ids) {
  // Get all the group-content that is now orphan.
  $orphans = array();
  $og_memberships = og_membership_load_multiple($ids);

  foreach ($og_memberships as $og_membership) {
    $entity_type = $og_membership->entity_type;
    $id = $og_membership->etid;
    // Don't delete users.
    if ($entity_type == 'user') {
      continue;
    }
    $entity_groups = og_get_entity_groups($entity_type, $id);
    // Orphan node can be relate to only one type of entity group.
    if (count($entity_groups) == 1) {
      $gids = reset($entity_groups);
      // Orphan node can be relate to only one node.
      if (count($gids) > 1) {
        continue;
      }
    }
    $orphans[$entity_type][] = $id;
  }

  if ($orphans) {
    foreach ($orphans as $entity_type => $orphan_ids) {
      entity_delete_multiple($entity_type, $orphan_ids);
    }
  }

  // Delete the OG memberships.
  og_membership_delete_multiple($ids);
}

/**
 * Helper function to move orphan group-content to another group.
 *
 * @param $ids
 *   Array of OG membership IDs.
 *
 * @see og_membership_delete_by_group_worker()
 */
function _og_orphans_move($ids, $group_type, $gid) {
  if (!og_is_group($group_type, $gid)) {
    $params = array(
      '@group-type' => $group_type,
      '@gid' => $gid,
    );
    throw new OgException(format_string('Cannot move orphan group-content to @group-type - @gid, as it is not a valid group.', $params));
  }

  $og_memberships = og_membership_load_multiple($ids);
  foreach ($og_memberships as $og_membership) {
    $entity_type = $og_membership->entity_type;
    $id = $og_membership->etid;
    if (count(og_get_entity_groups($entity_type, $id)) > 1) {
      continue;
    }
    $og_membership->group_type = $group_type;
    $og_membership->gid = $gid;
    $og_membership->save();
  }
}

/**
 * Register memberships for deletion.
 *
 * if the property "skip_og_membership_delete_by_group" exists on the
 * entity, this function will return early, and allow other implementing
 * modules to deal with the deletion logic.
 *
 * @param $entity_type
 *   The group type.
 * @param $entity
 *   The group entity object.
 */
function og_membership_delete_by_group($entity_type, $entity) {
  if (!empty($entity->skip_og_membership_delete_by_group)) {
    return;
  }

  list($gid) = entity_extract_ids($entity_type, $entity);
  $query = new EntityFieldQuery();
  $result = $query
    ->entityCondition('entity_type', 'og_membership')
    ->propertyCondition('group_type', $entity_type, '=')
    ->propertyCondition('gid', $gid, '=')
    ->execute();

  if (empty($result['og_membership'])) {
    return;
  }

  if (variable_get('og_use_queue', FALSE)) {
    $queue = DrupalQueue::get('og_membership_orphans');
    // Add item to the queue.
    $data = array(
      'group_type' => $entity_type,
      'gid' => $gid,
      // Allow implementing modules to determine the disposition (e.g. delete
      // orphan group content).
      'orphans' => array(
        'delete' => isset($entity->og_orphans['delete']) ? $entity->og_orphans['delete'] : variable_get('og_orphans_delete', FALSE),
        'move' => isset($entity->og_orphans['move']) ? $entity->og_orphans['move'] : array(),
      ),
    );

    // Exit now, as the task will be processed via queue.
    return $queue->createItem($data);
  }

  // No scalable solution was chosen, so just delete OG memberships.
  og_membership_delete_multiple(array_keys($result['og_membership']));
}

/**
 * Label callback; Return the label of OG membership entity.
 */
function og_membership_label($og_membership) {
  $wrapper = entity_metadata_wrapper('og_membership', $og_membership);
  $params = array(
    '@entity' => $wrapper->entity->label(),
    '@group' => $wrapper->group->label(),
  );
  return t('@entity in group @group', $params);
}

/**
 * Access callback for the group membership entity.
 */
function og_membership_access($op, $entity, $account = NULL, $entity_type = 'og_membership') {
  // No-end user needs access to this entity, so restrict it to admins.
  return user_access('administer group');
}


/**
 * Return TRUE if the entity is acting as a group.
 *
 * @param $entity_type
 *   The entity type.
 * @param $entity
 *   The entity object, or the entity ID.
 */
function og_is_group($entity_type, $entity) {
  $wrapper = entity_metadata_wrapper($entity_type, $entity);
  $bundle = $wrapper->getBundle();

  if (!field_info_instance($entity_type, OG_GROUP_FIELD, $bundle)) {
    return variable_get("og_is_group__{$entity_type}__{$bundle}", FALSE);
  }
  return !empty($wrapper->{OG_GROUP_FIELD}) && $wrapper->{OG_GROUP_FIELD}->value();
}


/**
 * 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_user_access_alter',
    'og_role_permissions',
    'og_get_user_roles',
    'og_get_permissions',
    'og_get_group_audience_fields',
    'og_get_entity_groups',
    'og_get_membership',
    'og_get_field_og_membership_properties',
    'og_get_user_roles',
  );

  foreach ($caches as $cache) {
    drupal_static_reset($cache);
  }
  // Let other OG modules know we invalidate cache.
  module_invoke_all('og_invalidate_cache', $gids);
}


/**
 * Return all existing groups of an entity type.
 */
function og_get_all_group($group_type = 'node') {
  if (!field_info_field(OG_GROUP_FIELD)) {
    return array();
  }

  $query = new EntityFieldQuery();
  $return = $query
    ->entityCondition('entity_type', $group_type)
    ->fieldCondition(OG_GROUP_FIELD, 'value', 1, '=')
    ->execute();

  return !empty($return[$group_type]) ? array_keys($return[$group_type]) : array();
}

/**
 * Get the first best matching group-audience field.
 *
 * @param $entity_type
 *   The entity type.
 * @param $entity
 *   The entity object.
 * @param $group_type
 *   The group type.
 * @param $group_bundle
 *   The group bundle.
 * @param $skip_access
 *   TRUE, if current user access to the field, should be skipped.
 *   Defaults to FALSE.
 */
function og_get_best_group_audience_field($entity_type, $entity, $group_type, $group_bundle, $skip_access = FALSE) {
  list(,, $bundle) = entity_extract_ids($entity_type, $entity);

  $field_names = og_get_group_audience_fields($entity_type, $bundle);
  if (!$field_names) {
    return;
  }
  foreach ($field_names as $field_name => $label) {
    $field = field_info_field($field_name);
    $settings = $field['settings'];
    if ($settings['target_type'] != $group_type) {
      // Group type doesn't match.
      continue;
    }
    if (!empty($settings['handler_settings']['target_bundles']) && !in_array($group_bundle, $settings['handler_settings']['target_bundles'])) {
      // Bundles don't match.
      continue;
    }


    if (!og_check_field_cardinality($entity_type, $entity, $field_name)) {
      // Field reached maximum.
      continue;
    }

    if (!$skip_access && !field_access('view', $field, $entity_type, $entity)) {
      // User can't access field.
      continue;
    }

    return $field_name;
  }
}

/**
 * Return TRUE if a field can be used and has not reached maximum values.
 *
 * @param $entity_type
 *   The entity type.
 * @param $entity
 *   The entity object or entity ID.
 * @param $field_name
 *   The group audience field name.
 */
function og_check_field_cardinality($entity_type, $entity, $field_name) {
  $field = field_info_field($field_name);
  if ($field['cardinality'] == FIELD_CARDINALITY_UNLIMITED) {
    return TRUE;
  }

  $wrapper = entity_metadata_wrapper($entity_type, $entity);
  return count($wrapper->{$field_name . '__og_membership'}->value(array('identifier' => TRUE))) < $field['cardinality'];
}

/**
 * Set an association (e.g. subscribe) an entity to a group.
 *
 * @param $group_type
 *   The entity type of the group.
 * @param $gid
 *   The group entity or ID.
 * @param $values
 *   Array with the information to pass along, until it is processed in the
 *   field handlers.
 *   - "entity_type": (optional) The entity type (e.g. "node" or "user").
 *     Defaults to 'user'
 *   - "entity": (optional) The entity object or entity Id to set the
 *     association. Defaults to the current user if the $entity_type property is
 *     set to 'user'.
 *   - "field_name": The name of the field, the membership should be registered
 *     in. If no value given, a first field with the correct membership type
 *     will be used. If no field found, an execpetion will be thrown.
 * @param $save_created
 *    (optional) If the OG membership is new, it determines whether the
 *    membership will be saved. Defaults to TRUE.
 *
 * @return
 *   The OG membership entity.
 */
function og_group($group_type, $gid, $values = array(), $save_created = TRUE) {
  global $user;
  // Set default values.
  $values += array(
    'entity_type' => 'user',
    'entity' => FALSE,
    'field_name' => FALSE,
    'state' => OG_STATE_ACTIVE,
  );

  $entity_type = $values['entity_type'];
  $entity = $values['entity'];
  $field_name = $values['field_name'];
  $state = $values['state'];

  if ($entity_type == 'user' && empty($entity)) {
    // We don't pass the object, as we want entity_metadata_wrapper() to reload
    // the user object.
    $entity = $user->uid;
  }

  $wrapper = entity_metadata_wrapper($entity_type, $entity);
  // If entity was an ID, get the object.
  $entity = $wrapper->value();
  $bundle = $wrapper->getBundle();
  $id = $wrapper->getIdentifier();

  if (is_object($gid)) {
    $group = $gid;

  }
  else {
    $group = entity_load_single($group_type, $gid);
  }

  // the group ID might be the entity, so re-popualte it.
  list($gid,, $group_bundle) = entity_extract_ids($group_type, $group);

  // Get membership if exists.
  $og_membership = og_get_membership($group_type, $gid, $entity_type, $id);

  if (!$og_membership && empty($field_name)) {
    $params = array(
      '%entity-type' => $entity_type,
      '%bundle' => $bundle,
      '%group-type' => $group_type,
      '%group-bundle' => $group_bundle,
    );

    // Allow getting fields not accessible by the user.
    $field_name = og_get_best_group_audience_field($entity_type, $entity, $group_type, $group_bundle, TRUE);
    if (!$field_name) {
      throw new OgException(format_string('There are no OG fields in entity %entity-type and bundle %bundle referencing %group-type - %group-bundle.', $params));
    }
  }

  if ($og_membership) {
    if (empty($og_membership->is_new) && $og_membership->field_name == $field_name && $og_membership->state == $state) {
      // Entity is already associated with group.
      return $og_membership;
    }
    elseif (!empty($field_name) && $og_membership->field_name != $field_name) {
      // Ungroup the current association, as it needs to change field.
      og_ungroup($group_type, $gid, $entity_type, $id);
      $og_membership = FALSE;
    }
    elseif ($og_membership->state != $state){
      // Change the state.
      $og_membership->state = $state;
    }
    else {
      // Nothing changed.
      return $og_membership;
    }
  }

  if (!$og_membership) {
    // Unset the values, so we don't try to process them.
    unset($values['entity_type'], $values['entity'], $values['field_name']);
    // Create a new OG membership.
    $og_membership = og_membership_create($group_type, $gid, $entity_type, $id, $field_name, $values);
  }

  if (empty($og_membership->is_new) || $save_created) {
    // Pass the entity object along to OgMembership::save() so we don't have
    // to reload it.
    $og_membership->entity = $entity;
    // Save the membership for update, or if the OG membership is new when
    // "save-created" is TRUE.
    $og_membership->save();
  }

  return $og_membership;
}

/**
 * Delete an association (e.g. unsubscribe) of an entity to a group.
 *
 * @param $group_type
 *   The entity type (e.g. "node").
 * @param $gid
 *   The group entity object or ID, to ungroup.
 * @param $entity_type
 *   (optional) The entity type (e.g. "node" or "user").
 * @param $etid
 *   (optional) The entity object or ID, to ungroup.
 *
 * @return
 *   The entity with the fields updated.
 */
function og_ungroup($group_type, $gid, $entity_type = 'user', $etid = NULL) {
  if (is_object($gid)) {
    list($gid) = entity_extract_ids($group_type, $gid);
  }

  if ($entity_type == 'user' && empty($etid)) {
    global $user;
    $etid = $user->uid;
  }
  elseif (is_object($etid)) {
    list($etid) = entity_extract_ids($entity_type, $etid);
  }

  if ($og_membership = og_get_membership($group_type, $gid, $entity_type, $etid)) {
    $og_membership->delete();
  }
}

/**
 * Determine whether a user has a given privilege.
 *
 * All permission checks in OG should go through this function. This
 * way, we guarantee consistent behavior, and ensure that the superuser
 * and group administrators can perform all actions.
 *
 * @param $group_type
 *   The entity type of the group.
 * @param $gid
 *   The entity ID of the group.
 * @param $string
 *   The permission, such as "administer group", being checked for.
 * @param $account
 *   (optional) The account to check. Defaults to the current user.
 * @param $skip_alter
 *   (optional) If TRUE then user access will not be sent to other modules
 *   using drupal_alter(). This can be used by modules implementing
 *   hook_og_user_access_alter() that still want to use og_user_access(), but
 *   without causing a recursion. Defaults to FALSE.
 * @param $ignore_admin
 *   (optional) When TRUE the specific permission is checked, ignoring the
 *   "administer group" permission if the user has it. When FALSE, a user
 *   with "administer group" will be granted all permissions.
 *   Defaults to FALSE.
 *
 * @return
 *   TRUE or FALSE if the current user has the requested permission.
 *   NULL, if the given group isn't a valid group.
 */
function og_user_access($group_type, $gid, $string, $account = NULL, $skip_alter = FALSE, $ignore_admin = FALSE) {
  global $user;
  $perm = &drupal_static(__FUNCTION__, array());
  // Mark the group ID and permissions that invoked an alter.
  $perm_alter = &drupal_static(__FUNCTION__ . '_alter', array());

  if (!og_is_group($group_type, $gid)) {
    // Not a group.
    return NULL;
  }


  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', $account) && !$ignore_admin) {
    return TRUE;
  }

  // Group manager has all privileges (if variable is TRUE).
  if (!empty($account->uid) && variable_get('og_group_manager_full_access', TRUE)) {
    $group = entity_load_single($group_type, $gid);
    if (!empty($group->uid) && $group->uid == $account->uid) {
      return TRUE;
    }
  }

  $identifier = $group_type . ':' . $gid;

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

    if ($roles = og_get_user_roles($group_type, $gid, $account->uid)) {
      // Member might not have roles if they are blocked.
      // A pending member is treated as a non-member.
      $role_permissions = og_role_permissions($roles);

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

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

  if (!$skip_alter && empty($perm_alter[$identifier][$account->uid][$string])) {
    // Let modules alter the permissions. since $perm is static we create
    // a clone of it.
    $group = !empty($group) ? $group : entity_load_single($group_type, $gid);
    $temp_perm = $perm[$identifier][$account->uid];
    $context = array(
      'string' => $string,
      'group_type' => $group_type,
      'group' => $group,
      'account' => $account,
    );
    drupal_alter('og_user_access', $temp_perm, $context);

    // Re-assing the altered permissions.
    $perm[$identifier][$account->uid] = $temp_perm;

    // Make sure alter isn't called for the same permissions.
    $perm_alter[$identifier][$account->uid][$string] = TRUE;
  }

  return !empty($perm[$identifier][$account->uid][$string]) || (!empty($perm[$identifier][$account->uid]['administer group']) && !$ignore_admin);
}

/**
 * Check if a user has access to a permission on a certain entity context.
 *
 * @param $perm
 *   The organic groups permission.
 * @param $entity_type
 *   The entity type.
 * @param $entity
 *   The entity object, or the entity ID.
 * @param $account
 *   (optional) The user object. If empty the current user will be used.
 *
 * @return
 *   Returns TRUE if the user has access to the permission, otherwise FALSE, or
 *   if the entity is not in OG context, function will return NULL. This allows
 *   a distinction between FALSE - no access, and NULL - no access as no OG
 *   context found.
 */
function og_user_access_entity($perm, $entity_type, $entity, $account = NULL) {
  if (empty($account)) {
    global $user;
    $account = clone $user;
  }

  // Set the default for the case there is not a group or a group content.
  $result = NULL;

  if (empty($entity)) {
    // $entity might be NULL, so return early.
    // @see field_access().
    return $result;
  }
  elseif (is_numeric($entity)) {
    $entity = entity_load_single($entity_type, $entity);
  }

  list($id, $vid, $bundle_name) = entity_extract_ids($entity_type, $entity);

  if (empty($id)) {
    // Entity isn't saved yet.
    return $result;
  }

  $is_group = og_is_group($entity_type, $entity);
  $is_group_content = og_is_group_content_type($entity_type, $bundle_name);

  if ($is_group) {
    if (og_user_access($entity_type, $id, $perm, $account)) {
      return TRUE;
    }
    else {
      // An entity can be a group and group content in the same time. The group
      // didn't return TRUE, but the user still might have access to the
      // permission in group content context.
      $result = FALSE;
    }
  }

  if ($is_group_content && $groups = og_get_entity_groups($entity_type, $entity)) {
    foreach ($groups as $group_type => $gids) {
      foreach ($gids as $gid) {
        if (og_user_access($group_type, $gid, $perm, $account)) {
          return TRUE;
        }
      }
    }
    return FALSE;
  }

  // Either the user didn't have permission, or the entity might be a
  // disabled group or an orphaned group content.
  return $result;
}

/**
 * Get the groups an entity is associated with.
 *
 * @param $entity_type
 *   The entity type. Defaults to 'user'
 * @param $entity
 *   (optional) The entity object or entity ID. If empty, and $entity_type is
 *   "user", the current user will be used.
 * @param $states
 *   (optional) Array with the state to return. Defaults to active.
 * @param $field_name
 *   (optional) The field name associated with the group.
 *
 * @return
 *  An array with the group's entity type as the key, and array - keyed by
 *  the OG membership ID and the group ID as the value. If nothing found,
 *  then an empty array.
 */
function og_get_entity_groups($entity_type = 'user', $entity = NULL, $states = array(OG_STATE_ACTIVE), $field_name = NULL) {
  $cache = &drupal_static(__FUNCTION__, array());

  if ($entity_type == 'user' && empty($entity)) {
    global $user;
    $entity = clone $user;
  }
  if (is_object($entity)) {
    // Get the entity ID.
    list($id) = entity_extract_ids($entity_type, $entity);
  }
  else {
    $id = $entity;
  }

  // Get a string identifier of the states, so we can retrieve it from cache.
  if ($states) {
    sort($states);
    $state_identifier = implode(':', $states);
  }
  else {
    $state_identifier = FALSE;
  }

  $identifier = array(
    $entity_type,
    $id,
    $state_identifier,
    $field_name,
  );

  $identifier = implode(':', $identifier);

  if (isset($cache[$identifier])) {
    // Return cached values.
    return $cache[$identifier];
  }

  $cache[$identifier] = array();

  $query = db_select('og_membership', 'ogm')
    ->fields('ogm', array('id', 'gid', 'group_type'))
    ->condition('entity_type', $entity_type)
    ->condition('etid', $id);

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

  if ($field_name) {
    $query->condition('field_name', $field_name);
  }

  $result = $query
    ->execute()
    ->fetchAll();

  foreach ($result as $row) {
    $cache[$identifier][$row->group_type][$row->id] = $row->gid;
  }

  return $cache[$identifier];
}

/**
 * Return TRUE if field is a group audience type.
 *
 * @param $field_name
 *   The field name.
 */
function og_is_group_audience_field($field_name) {
  $field = field_info_field($field_name);
  return $field['type'] == 'entityreference' && ($field['settings']['handler'] == 'og' || strpos($field['settings']['handler'], 'og_') === 0);
}

/**
 * Get the name of the group-audience type field.
 *
 * @param $entity_type
 *   The entity type.
 * @param $bundle_name
 *   The bundle name to be checked.
 * @param $group_type
 *   Filter list to only include fields referencing a specific group type.
 * @param $group_bundle
 *   Filter list to only include fields referencing a specific group bundle.
 *   Fields that do not specify any bundle restrictions at all are also
 *   included.
 *
 * @return
 *   Array keyed with the field name and the field label as the value.
 */
function og_get_group_audience_fields($entity_type = 'user', $bundle_name = 'user', $group_type = NULL, $group_bundle = NULL) {
  $return = &drupal_static(__FUNCTION__, array());
  $identifier = $entity_type . ':' . $bundle_name . ':' . $group_type . ':' . $group_bundle;
  if (isset($return[$identifier])) {
    return $return[$identifier];
  }
  $return[$identifier] = array();

  foreach (field_info_instances($entity_type, $bundle_name) as $field_name => $instance) {
    if (!og_is_group_audience_field($field_name)) {
      continue;
    }
    $field_info = field_info_field($instance['field_name']);
    if (isset($group_type) && $field_info['settings']['target_type'] != $group_type) {
      continue;
    }
    if ($group_bundle && !empty($field_info['settings']['handler_settings']['target_bundles']) && !in_array($group_bundle, $field_info['settings']['handler_settings']['target_bundles'])) {
      continue;
    }
    $return[$identifier][$field_name] = $instance['label'];
  }
  return $return[$identifier];
}

/**
 * Return the group type (i.e. "group" or "group_content") of an entity.
 *
 * @param $entity_type
 *   The entity type.
 * @param $bundle_name
 *   The bundle name to be checked.
 * @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)og_get_group_audience_fields($entity_type, $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 $entity_type
 *   The entity type to be checked.
 */
function og_is_group_content_type($entity_type, $bundle_name) {
  return og_get_group_type($entity_type, $bundle_name, 'group content');
}

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

  foreach (entity_get_info() as $entity_type => $entity_value) {
    foreach ($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 all bundles that are a group type.
 *
 * @return
 *  An associative array whose keys are entity types, and whose values are
 *  arrays of bundles for that entity type. The array of bundles is keyed by
 *  bundle machine name, and the values are bundle labels.
 */
function og_get_all_group_bundle() {
  $return = array();

  foreach (entity_get_info() as $entity_type => $entity_value) {
    foreach ($entity_value['bundles'] as $bundle => $bundle_value) {
      if (og_is_group_type($entity_type, $bundle)) {
        $return[$entity_type][$bundle] = check_plain($bundle_value['label']);
      }
    }
  }
  return $return;

}

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

  foreach (entity_get_info() as $entity_type => $entity_value) {
    foreach ($entity_value['bundles'] as $bundle => $bundle_value) {
      if (og_is_group_content_type($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 all the entities that are a group content.
 *
 * @return
 *   Array keyed with the entity type machine name and the entity human readable
 *   name as the value, or an empty array if no entities are defined as group
 *   content.
 */
function og_get_all_group_content_bundle() {
  $return = array();

  foreach (entity_get_info() as $entity_type => $entity_value) {
    foreach ($entity_value['bundles'] as $bundle => $bundle_value) {
      if (og_is_group_content_type($entity_type, $bundle)) {
        $return[$entity_type][$bundle] = check_plain($bundle_value['label']);
      }
    }
  }
  return $return;
}

/**
 * Return TRUE if entity belongs to a group.
 *
 * @param $group_type
 *   The entity type of the 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.
 * @param $states
 *   (optional) Array with the state to return. If empty groups of all state will
 *   return.
 *
 * @return
 *   TRUE if the entity (e.g. the user) belongs to a group and is not pending or
 *   blocked.
 */
function og_is_member($group_type, $gid, $entity_type = 'user', $entity = NULL, $states = array(OG_STATE_ACTIVE)) {
  $groups = og_get_entity_groups($entity_type, $entity, $states);
  return !empty($groups[$group_type]) && in_array($gid, $groups[$group_type]);
}

/**
 * Check if group should use default roles and permissions.
 *
 * @param $group_type
 *   The entity type of the group.
 * @param $gid
 *   The group ID or the group entity.
 *
 * @return
 *   TRUE if group should use default roles and permissions.
 */
function og_is_group_default_access($group_type, $gid) {
  $wrapper = entity_metadata_wrapper($group_type, $gid);
  $bundle = $wrapper->getBundle();

  if (!field_info_instance($group_type, OG_DEFAULT_ACCESS_FIELD, $bundle)) {
    return variable_get("og_is_group_default_access__{$group_type}__{$bundle}", TRUE);
  }

  if (empty($wrapper->{OG_DEFAULT_ACCESS_FIELD})) {
    return TRUE;
  }

  return !$wrapper->{OG_DEFAULT_ACCESS_FIELD}->value();
}

/**
 * Determine the permissions for one or more roles.
 *
 * @param $roles
 *   An array whose keys are the role IDs of interest.
 *
 * @return
 *   An array indexed by role ID. Each value is an array whose keys are the
 *   permission strings for the given role ID.
 */
function og_role_permissions($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 $group_type
 *   The group type.
 * @param $bundle
 *   The bundle type.
 * @param $gid
 *   The group ID.
 * @param $force_group
 *   (optional) 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().
 * @param $include_all
 *   (optional) If TRUE then the anonymous and authenticated default roles will
 *   be included.
 *
 * @return
 *   An associative array with the role id as the key and the role name as
 *   value. The anonymous and authenticated default roles are on the top of the
 *   array.
 */
function og_roles($group_type, $bundle, $gid = 0, $force_group = FALSE, $include_all = TRUE) {
  if ($gid && !$bundle) {
    $wrapper = entity_metadata_wrapper($group_type, $gid);
    $bundle = $wrapper->getBundle();
  }

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

  $query = db_select('og_role', 'ogr')
    ->fields('ogr', array('rid', 'name'))
    ->condition('group_type', $group_type, '=')
    ->condition('group_bundle', $bundle, '=')
    ->condition('gid', $query_gid, '=')
    ->orderBy('rid', 'ASC');

  if (!$include_all) {
    $query->condition('name', array(OG_ANONYMOUS_ROLE, OG_AUTHENTICATED_ROLE), 'NOT IN');
  }
  $rids = $query
    ->execute()
    ->fetchAllkeyed();

  return $rids;
}

/**
 * Get array of default roles, keyed by their declaring module.
 *
 * @param $include
 *   (optional) If TRUE also anonymous and authenticated roles will be returned.
 *   Defaults to TRUE.
 *
 * @return
 *   Array of default roles, grouped by module name.
 */
function og_get_default_roles($include = TRUE) {
  $roles = array();
  foreach (module_implements('og_default_roles') as $module) {
    $roles = array_merge($roles, 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 ($include) {
    array_unshift($roles, OG_AUTHENTICATED_ROLE);
    array_unshift($roles, OG_ANONYMOUS_ROLE);
  }

  return $roles;
}

/**
 * Get all roles of a user in a certain group.
 *
 * @param $group_type
 *   The entity type of the group.
 * @param $gid
 *   The group ID.
 * @param $uid
 *   (optional) Integer specifying the user ID. By default an ID of current
 *   logged in user will be used.
 * @param $include
 *   (optional) If TRUE also anonymous or authenticated role ID will be
 *   returned. Defaults to TRUE.
 * @param $check_active
 *   (optional) If TRUE, and the user is pending, only anonymous role will be
 *   returned. If blocked, no role will be returned.
 *
 * @return
 *   Array with the role IDs of the user as the key, and the role name as
 *   the value.
 */
function og_get_user_roles($group_type, $gid, $uid = NULL, $include = TRUE, $check_active = TRUE) {
  $roles = &drupal_static(__FUNCTION__, array());
  if (empty($uid)) {
    global $user;
    $uid = $user->uid;
  }

  $account = user_load($uid);

  $identifier = implode(':', array($group_type, $gid, $uid, $include));
  if (isset($roles[$identifier])) {
    return $roles[$identifier];
  }

  $is_blocked = og_is_member($group_type, $gid, 'user', $account, array(OG_STATE_BLOCKED));

  if ($check_active && $is_blocked) {
    $roles[$identifier] = array();
    return $roles[$identifier];
  }

  $is_member = og_is_member($group_type, $gid, 'user', $account);


  $rids = array();
  $group = entity_load_single($group_type, $gid);
  // Get the bundle of the group.
  list(,, $bundle) = entity_extract_ids($group_type, $group);

  // Check if roles are overriden for the group.
  $query_gid = og_is_group_default_access($group_type, $gid) ? 0 : $gid;

  if (!$check_active || $is_member) {
    $query = db_select('og_users_roles', 'ogur');
    $query->innerJoin('og_role', 'ogr', 'ogur.rid = ogr.rid');

    $rids = $query
      ->fields('ogur', array('rid'))
      ->fields('ogr', array('name'))
      ->condition('ogr.group_type', $group_type, '=')
      ->condition('ogr.group_bundle', $bundle, '=')
      ->condition('ogr.gid', $query_gid, '=')
      ->condition('ogur.uid', $uid, '=')
      ->condition('ogur.gid', $gid, '=')
      ->orderBy('rid')
      ->execute()
      ->fetchAllkeyed();
  }


  if ($include && !$is_blocked) {
    $role_name = $is_member ? OG_AUTHENTICATED_ROLE : OG_ANONYMOUS_ROLE;

    $rids = db_select('og_role', 'ogr')
      ->fields('ogr', array('rid', 'name'))
      ->condition('group_type', $group_type, '=')
      ->condition('group_bundle', $bundle, '=')
      ->condition('gid', $query_gid, '=')
      ->condition('name', $role_name, '=')
      ->execute()
      ->fetchAllkeyed() + $rids;
  }

  $roles[$identifier] = $rids;
  return $rids;
}

/**
 * Create a stub OG role object.
 *
 * @param $name
 *   A name of the role.
 * @param $group_type
 *   (optional) The entity type of the group.
 * @param $gid
 *   (optional) The group ID.
 * @param $group_bundle
 *   (optional) The bundle of the group.
 *
 * @return
 *   A stub OG role object.
 */
function og_role_create($name, $group_type = '', $gid = 0, $group_bundle = '') {
  $role = new stdClass;
  $role->name = $name;
  $role->gid = $gid;
  $role->group_type = $group_type;
  $role->group_bundle = $group_bundle;
  return $role;
}

/**
 * Fetch a user role from database.
 *
 * @param $rid
 *   An integer with the role ID.
 *
 * @return
 *   A fully-loaded role object if a role with the given ID exists,
 *   FALSE otherwise.
 */
function og_role_load($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 $role->rid is not specified, a new
 *   role will be created.
 *
 * @return
 *   Status constant indicating if role was created or updated.
 *   Failure to write the user role record will return FALSE. Otherwise.
 *   SAVED_NEW or SAVED_UPDATED is returned depending on the operation
 *   performed.
 */
function og_role_save($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_role_update', $role);
  }
  else {
    $status = drupal_write_record('og_role', $role);
    module_invoke_all('og_role_insert', $role);
  }

  og_invalidate_cache();
  return $status;
}

/**
 * Delete a user role from database.
 *
 * @param $rid
 *   An integer with the role ID.
 */
function og_role_delete($rid) {
  $role = og_role_load($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_role_delete', $role);

  og_invalidate_cache();
}

/**
 * Delete all roles belonging to a group.
 *
 * This will also maintain user roles when revertting an ovverriden group.
 * For example, if in the overridden group users were assigned to the role
 * "administrator", upon reverting back to default roles and
 * permissions, OG will search for existing roles with that name, and re-assign
 * the correct role ID, and the users that had "administrator" will still have
 * it.
 *
 * @param $group_type
 *   The group type.
 * @param $gid
 *   The group ID.
 */
function og_delete_user_roles_by_group($group_type, $group) {
  // Check if group has overriden roles defined.
  list($gid, $vid,$bundle) = entity_extract_ids($group_type, $group);
  $global_roles = array_flip(og_roles($group_type, $bundle));
  if ($roles = og_roles($group_type, $bundle, $gid, TRUE)) {
    foreach ($roles as $rid => $name) {

      if (variable_get('og_maintain_overridden_roles', TRUE) && !empty($global_roles[$name])) {
        // Role name exists in the global roles, update the role ID to the
        // global one.
        db_update('og_users_roles')
          ->fields(array('rid' => $global_roles[$name]))
          ->condition('rid', $rid)
          ->condition('group_type', $group_type)
          ->condition('gid', $gid)
          ->execute();
      }

      og_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()) {
  if ($rids) {
    $query = db_query("SELECT rid, name FROM {og_role} WHERE rid IN (:rids)", array(':rids' => $rids));
  }
  else {
    $query = db_query("SELECT rid, name FROM {og_role}");
  }
  return $query->fetchAllKeyed();
}


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

/**
 * Create new roles, based on the default roles and permissions.
 *
 * @param $group_type
 *   The group type.
 * @param $bundle
 *   The bundle type.
 * @param $gid
 *   The group ID.
 *
 * @return
 *   The newly created roles keyed by role ID and role name as the value. Or
 *   FALSE if no roles were created.
 */
function og_roles_override($group_type, $bundle, $gid) {
  // Check if roles aren't already overridden. We can't use
  // og_is_group_default_access() as the field is already set, so we
  // check to see if there are new roles in the database by setting
  // "force group" parameter to TRUE.
  if (og_roles($group_type, $bundle, $gid, TRUE)) {
    return;
  }

  $rids = array();
  if ($gid) {
    // Copy roles from a specific group
    $og_roles = og_roles($group_type, $bundle);
    $perms = og_role_permissions($og_roles);
  }
  else {
    // Copy the global default roles
    $og_roles = og_get_default_roles();
    $perms = og_get_default_permissions();
  }

  foreach ($og_roles as $rid => $name) {
    $role = og_role_create($name, $group_type, $gid, $bundle);
    og_role_save($role);

    $rids[$role->rid] = $role->name;
    og_role_change_permissions($role->rid, $perms[$rid]);

    // Remap the default roles, to the newely created ones.
    db_update('og_users_roles')
      ->fields(array('rid' => $role->rid))
      ->condition('rid', $rid)
      ->condition('group_type', $group_type)
      ->condition('gid', $gid)
      ->execute();
  }

  return $rids;
}

/**
 * Grant a group role to a user.
 *
 * @param $group_type
 *   The entity type of the group.
 * @param $gid
 *   The group ID.
 * @param $uid
 *   The user ID.
 * @param $rid
 *   The role ID.
 */
function og_role_grant($group_type, $gid, $uid, $rid) {
  // Make sure the role is valid.
  $group = entity_load_single($group_type, $gid);
  list(,, $bundle) = entity_extract_ids($group_type, $group);
  $og_roles = og_roles($group_type, $bundle, $gid, FALSE, FALSE);
  if (empty($og_roles[$rid])) {
    // Role isn't valid.
    return;
  }

  // Get the existing user roles.
  $user_roles = og_get_user_roles($group_type, $gid, $uid);
  if (empty($user_roles[$rid])) {
    $role = new stdClass();
    $role->uid = $uid;
    $role->rid = $rid;
    $role->group_type = $group_type;
    $role->gid = $gid;

    drupal_write_record('og_users_roles', $role);
    og_invalidate_cache();
    module_invoke_all('og_role_grant', $group_type, $gid, $uid, $rid);

    if (module_exists('rules'))  {
      rules_invoke_event('og_role_grant', og_get_membership($group_type, $gid, 'user', $uid), entity_metadata_wrapper('user', $uid), $rid);
    }
  }
}

/**
 * Revoke a group role from a user.
 *
 * @param $group_type
 *   The entity type of the group.
 * @param $gid
 *   The group ID.
 * @param $uid
 *   The user ID.
 * @param $rid
 *   The role ID.
 */
function og_role_revoke($group_type, $gid, $uid, $rid) {
  $og_roles = og_get_user_roles($group_type, $gid, $uid);
  if (!empty($og_roles[$rid])) {
    db_delete('og_users_roles')
      ->condition('uid', $uid)
      ->condition('rid', $rid)
      ->condition('group_type', $group_type)
      ->condition('gid', $gid)
      ->execute();
    og_invalidate_cache();
    module_invoke_all('og_role_revoke', $group_type, $gid, $uid, $rid);

    if (module_exists('rules'))  {
      rules_invoke_event('og_role_revoke', og_get_membership($group_type, $gid, 'user', $uid), entity_metadata_wrapper('user', $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 $permissions.
 *
 * @see og_role_grant_permissions()
 * @see og_role_revoke_permissions()
 */
function og_role_change_permissions($rid, array $permissions = array()) {
  // Grant new permissions for the role.
  $grant = array_filter($permissions);
  if (!empty($grant)) {
    og_role_grant_permissions($rid, array_keys($grant));
  }
  // Revoke permissions for the role.
  $revoke = array_diff_assoc($permissions, $grant);
  if (!empty($revoke)) {
    og_role_revoke_permissions($rid, array_keys($revoke));
  }

  if (!empty($grant) || !empty($revoke)) {
    // Allow modules to be notified on permission changes.
    $role = og_role_load($rid);
    module_invoke_all('og_role_change_permissions', $role, $grant, $revoke);
  }
}

/**
 * Grant permissions to a user role.
 *
 * @param $rid
 *   The ID of a user role to alter.
 * @param $permissions
 *   A list of permission names to grant.
 *
 * @see user_role_change_permissions()
 * @see user_role_revoke_permissions()
 */
function og_role_grant_permissions($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 $permissions
 *   A list of permission names to revoke.
 *
 * @see user_role_change_permissions()
 * @see user_role_grant_permissions()
 */
function og_role_revoke_permissions($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 by implementing modules.
 *
 * @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 default permissions.
 *
 * @return
 *   Array keyed with the anonymous, authenticated and administror and the
 *   permissions that should be enabled by default.
 */
function og_get_default_permissions() {
  $roles = og_get_default_roles();
  $default_perms = og_get_permissions();
  $perms = array();

  foreach ($roles as $rid => $role_name) {
    $perms[$rid] = array();
    // For each default role, iterate default permissions and mark the
    // permissions that set the role as default.
    foreach ($default_perms as $perm_name => $perm) {
      if (in_array($role_name, $perm['default role'])) {
        $perms[$rid][$perm_name] = TRUE;
      }
    }
  }

  return $perms;
}

/**
 * Get all the modules fields that can be assigned to fieldable entities.
 *
 * @param $field_name
 *   The field name that was registered for the definition.
 *
 * @return
 *   An array with the field and instance definitions, or FALSE if not
 *   found.
 */
function og_fields_info($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(),
            'multiple' => FALSE,
            'description' => '',
          );

          // 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);
  }

  if (!empty($field_name)) {
    return !empty($return[$field_name]) ?  $return[$field_name] : FALSE;
  }

  return $return;
}

/**
 * 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()) {
  $entity = entity_load_single($entity_type, $etid);
  $label = entity_label($entity_type, $entity);
  $uri = entity_uri($entity_type, $entity);
  drupal_set_breadcrumb(array_merge(array(l(t('Home'), '<front>')), array(l($label, $uri['path'])), $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.
 * @param $og_field
 *   (optional) Array with field definitions, to allow easier overriding by the
 *   caller. If empty, function will get the field info by calling
 *   og_fields_info() with the field name.
 */
function og_create_field($field_name, $entity_type, $bundle, $og_field = array()) {
  if (empty($og_field)) {
    $og_field = og_fields_info($field_name);
  }

  $field = field_info_field($field_name);
  // Allow overriding the field name.
  $og_field['field']['field_name'] = $field_name;
  if (empty($field)) {
    $field = field_create_field($og_field['field']);
  }

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

    field_create_instance($instance);
    // Clear the entity property info cache, as OG fields might add different
    // entity property info.
    og_invalidate_cache();
    entity_property_info_cache_clear();
  }
}

/**
 * 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 content 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'),
  );
}

/**
 * Return a list of fieldable entities.
 *
 * @return
 *  Array keyed with the entity machine name and the saniztized human name as
 *  the value.
 */
function og_get_fieldable_entity_list() {
  $return = array();
  foreach (entity_get_info() as $name => $info) {
    if (!empty($info['fieldable'])) {
      $return[$name] = check_plain($info['label']);
    }
  }
  return $return;
}

/**
 * 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) {
  $info = node_type_get_type($type);
  $type = check_plain($info->type);
  $perms = array();

  // Check type is of group content.
  if (og_is_group_content_type('node', $type)) {
    // Build standard list of node permissions for this type.
    $perms += array(
      "create $type content" => array(
        'title' => t('Create %type_name content', array('%type_name' => $info->name)),

      ),
      "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)),
      ),
    );

    if (!module_exists('entityreference_prepopulate')) {
      // We allow the create permission only on members, as otherwise we would
      // have to iterate over every single group to decide if the user has
      // permissions for it.
      $perms["create $type content"]['roles'] = array(OG_AUTHENTICATED_ROLE);
    }

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

/**
 * Return a form element with crafted links to create nodes for a group.
 *
 * @param $group_type
 *   The entity type of the group.
 * @param $gid
 *   The group ID.
 * @param $field_name
 *   The group audience field name.
 * @param $destination
 *   (optional) The destiantion after a node is created. Defaults to the
 *   destination passed in the URL if exists, otherwise back to the current
 *   page. FALSE to not append any destination to node create links.
 * @param $types
 *   (optional) An array of type names. Restrict the created links to the given
 *   types.
 */
function og_node_create_links($group_type, $gid, $field_name, $destination = NULL, $types = NULL) {
  if (!og_is_group($group_type, $gid)) {
    return;
  }

  $types = isset($types) ? $types : array_keys(node_type_get_types());
  foreach ($types as $type_name) {
    if (!og_is_group_content_type('node', $type_name) || !og_user_access($group_type, $gid, "create $type_name content")) {
      continue;
    }

    $instance = field_info_instance('node', $field_name, $type_name);
    if (empty($instance['settings']['behaviors']['prepopulate']['status'])) {
      // Instance doesn't allow prepopulating.
      continue;
    }
    $names[$type_name] = node_type_get_name($type_name);
  }

  if (empty($names)) {
    return;
  }

  // Sort names.
  asort($names);

  // Build links.
  $options  = array(
    'query' => array($field_name => $gid),
  );

  if ($destination) {
    $options['query']['destination'] = $destination;
  }
  elseif ($destination !== FALSE) {
    $options['query'] += drupal_get_destination();
  }

  $items = array();
  foreach ($names as $type => $name) {
    // theme_item_list's 'data' items isn't a render element, so use l().
    // http://drupal.org/node/891112
    $items[] = array('data' => l($name, 'node/add/' . str_replace('_', '-', $type), $options));
  }

  $element = array();
  $element['og_node_create_links'] = array(
    '#theme' => 'item_list',
    '#items' => $items,
  );

  return $element;
}

/**
 * Get the group IDs of all the groups a user is an approved member of.
 *
 * @param $account
 *   (optional) The user object to fetch group memberships for. Defaults to the
 *   acting user.
 * @param $group_type
 *   (optional) The entity type of the groups to fetch. By default all group
 *   types will be fetched.
 *
 * @return
 *   An array with the group IDs or an empty array.
 */
function og_get_groups_by_user($account = NULL, $group_type = NULL) {
  if (empty($account)) {
    global $user;
    $account = $user;
  }

  if (!og_get_group_audience_fields()) {
    // User entity doesn't have group audience fields.
    return;
  }

  $gids = array();

  // Get all active OG membership that belong to the user.
  $wrapper = entity_metadata_wrapper('user', $account->uid);
  $og_memberships = $wrapper->{'og_membership__' . OG_STATE_ACTIVE}->value();
  if (!$og_memberships) {
    return;
  }

  foreach ($og_memberships as $og_membership) {
    if (!empty($og_membership)) {
      $gids[$og_membership->group_type][$og_membership->gid] = $og_membership->gid;
    }
  }

  if (empty($group_type)) {
    return $gids;
  }
  elseif (!empty($gids[$group_type])) {
    return $gids[$group_type];
  }
}

/**
 * Implements hook_action_info().
 *
 * @see views_bulk_operations_action_info()
 */
function og_action_info() {
  $actions = array();
  $files = og_operations_load_action_includes();
  foreach ($files as $filename) {
    $action_info_fn = 'og_'. str_replace('.', '_', basename($filename, '.inc')).'_info';
    $action_info = call_user_func($action_info_fn);
    if (is_array($action_info)) {
      $actions += $action_info;
    }
  }

  return $actions;
}

/**
 * Loads the VBO actions placed in their own include files.
 *
 * @return
 *   An array of containing filenames of the included actions.
 *
 * @see views_bulk_operations_load_action_includes()
 */
function og_operations_load_action_includes() {
 static $loaded = FALSE;

  $path = drupal_get_path('module', 'og') . '/includes/actions/';
  $files = array(
    'user_roles.action.inc',
    'set_state.action.inc',
    'membership_delete.action.inc',
  );

  if (!$loaded) {
    foreach ($files as $file) {
      include_once $path . $file;
    }
    $loaded = TRUE;
  }

  return $files;
}


/**
 * Implements hook_features_api().
 */
function og_features_api() {
  return array(
    'og_features_role' => array(
      'name' => t('OG Role'),
      'feature source' => TRUE,
      'default_hook' => 'og_features_default_roles',
      'default_file' => FEATURES_DEFAULTS_INCLUDED,
      'file' => drupal_get_path('module', 'og') . '/includes/og_features_role.features.inc',
    ),
    'og_features_permission' => array(
      'name' => t('OG Permissions'),
      'feature_source' => TRUE,
      'default_hook' => 'og_features_default_permissions',
      'default_file' => FEATURES_DEFAULTS_INCLUDED,
      'file' => drupal_get_path('module', 'og') . '/includes/og_features_permission.features.inc',
    ),
  );
}

/**
 * Implements hook_features_pipe_alter().
 *
 * Prevent OG related fields from being piped in features, when a content
 * type that has them is selected.
 *
 * This if compatible with Features 1.x and 2.x
 */
function og_features_pipe_alter(&$pipe, $data, $export) {
  if (!variable_get('og_features_ignore_og_fields', FALSE)) {
    return;
  }

  if (empty($pipe['field']) && empty($pipe['field_base']) && empty($pipe['field_instance'])) {
    // The exported item is not a field.
    return;
  }

  if (!empty($pipe['field_instance'])) {
    $key = 'field_instance';
    $explode = TRUE;
  }
  elseif (!empty($pipe['field_base'])) {
    $key = 'field_base';
    $explode = FALSE;
  }
  else {
    $key = 'field';
    $explode = TRUE;
  }

  foreach ($pipe[$key] as $delta => $value) {
    if ($explode) {
      // Get the field name from the [entity-type]-[bundle]-[field-name].
      $args = explode('-', $value);
      $field_name = $args[2];
    }
    else {
      $field_name = $value;
    }

    if (og_fields_info($field_name) || og_is_group_audience_field($field_name)) {
      unset($pipe[$key][$delta]);
    }
  }
}

/**
 * Implements hook_migrate_api().
 */
function og_migrate_api() {
  $migrations = array();
  if (db_table_exists('d6_og')) {
    $migrations['OgMigrateAddFields'] = array('class_name' => 'OgMigrateAddFields');
    $migrations['OgMigrateContent'] = array('class_name' => 'OgMigrateContent');
    $migrations['OgMigrateUser'] = array('class_name' => 'OgMigrateUser');

    foreach (node_type_get_names() as $bundle => $value) {
      $machine_name = 'OgMigrateGroup' . ucfirst($bundle);
      $migrations[$machine_name] = array(
        'class_name' => 'OgMigrateGroup',
        'bundle' => $bundle,
      );
    }

    if (db_table_exists('d6_og_users_roles')) {
      // OG user roles (OGUR) related migrations.
      $migrations['OgMigrateOgurRoles'] = array('class_name' => 'OgMigrateOgurRoles');
      $migrations['OgMigrateOgur'] = array('class_name' => 'OgMigrateOgur');
    }
  }
  elseif (db_field_exists('og_membership', 'group_type') && db_table_exists('og') && !db_table_exists('d6_og')) {
    $migrations['OgMigrateMembership'] = array('class_name' => 'OgMigrateMembership');
    $migrations['OgMigrateRoles'] = array('class_name' => 'OgMigrateRoles');
    $migrations['OgMigrateUserRoles'] = array('class_name' => 'OgMigrateUserRoles');
  }

  $api = array(
    'api' => 2,
    'migrations' => $migrations,
  );
  return $api;
}

/**
 * Implements hook_flush_caches().
 */
function og_flush_caches() {
  $bins = array(
    'cache_entity_og_membership',
    'cache_entity_og_membership_type',
  );
  return $bins;
}