bp_groups_filter_folder_scope( $retval = array(),  $filter = array() )

function bp_groups_filter_folder_scope( $retval = array(), $filter = array() ) {

	if ( ! bp_is_group_document_support_enabled() ) {
		return $retval;
	}

	// Determine the user_id.
	if ( ! empty( $filter['user_id'] ) ) {
		$user_id = $filter['user_id'];
	} else {
		$user_id = bp_displayed_user_id()
			? bp_displayed_user_id()
			: bp_loggedin_user_id();
	}

	$folder_id = 0;
	$folders = array();

	if ( ! empty( $filter['folder_id'] ) ) {
		$folder_id = (int) $filter['folder_id'];
	}

	if ( 'groups' !== $filter['scope'] ) {
		// Fetch public groups.
		$public_groups = groups_get_groups( array(
			'fields'   => 'ids',
			'status'   => 'public',
			'per_page' => - 1,
		) );
	}

	if ( ! empty( $public_groups['groups'] ) ) {
		$public_groups = $public_groups['groups'];
	} else {
		$public_groups = array();
	}

	// Determine groups of user.
	$groups = groups_get_user_groups( $user_id );
	if ( ! empty( $groups['groups'] ) ) {
		$groups = $groups['groups'];
	} else {
		$groups = array();
	}

	$group_ids = false;
	if ( ! empty( $groups ) && ! empty( $public_groups ) ) {
		$group_ids = array( 'groups' => array_unique( array_merge( $groups, $public_groups ) ) );
	} elseif ( empty( $groups ) && ! empty( $public_groups ) ) {
		$group_ids = array( 'groups' => $public_groups );
	} elseif ( ! empty( $groups ) && empty( $public_groups ) ) {
		$group_ids = array( 'groups' => $groups );
	}

	if ( empty( $group_ids ) ) {
		$group_ids = array( 'groups' => array() );
	}

	if ( bp_is_group() ) {
		$group_ids = array( 'groups' => array( bp_get_current_group_id() ) );
	}

	if ( ! empty( $filter['search_terms'] ) ) {
		if ( ! empty( $folder_id ) ) {
			$folder_ids = array();
			$fetch_folder_ids = bp_document_get_folder_children( (int) $folder_id );
			if ( $fetch_folder_ids ) {
				foreach ( $fetch_folder_ids as $single_folder ) {
					$single_folder_ids = bp_document_get_folder_children( (int) $single_folder );
					if ( $single_folder_ids ) {
						array_merge( $folder_ids, $single_folder_ids );
					}
					array_push( $folder_ids, $single_folder );
				}
			}

			$folder_ids[] = $folder_id;
			$folders      = array(
				'column'  => 'parent',
				'compare' => 'IN',
				'value'   => $folder_ids,
			);
		}
	} else {
		if ( ! empty( $folder_id ) ) {
			$folders = array(
				'column'  => 'parent',
				'compare' => '=',
				'value'   => $folder_id,
			);
		} else {
			$folders = array(
				'column' => 'parent',
				'value'  => 0,
			);
		}
	}

	$args = array(
		'relation' => 'AND',
		array(
			'column'  => 'group_id',
			'compare' => 'IN',
			'value'   => (array) $group_ids['groups'],
		),
		array(
			'column' => 'privacy',
			'value'  => 'grouponly',
		),
		$folders,
	);

	return $args;
}