bp_document_add( array|string $args = '' )

function bp_document_add( $args = '' ) {

	$r = bp_parse_args(
		$args,
		array(
			'id'            => false,                   // Pass an existing document ID to update an existing entry.
			'blog_id'       => get_current_blog_id(),   // Blog ID.
			'attachment_id' => false,                   // attachment id.
			'user_id'       => bp_loggedin_user_id(),   // user_id of the uploader.
			'title'         => '',                      // title of document being added.
			'folder_id'     => false,                   // Optional: ID of the folder.
			'group_id'      => false,                   // Optional: ID of the group.
			'activity_id'   => false,                   // The ID of activity.
			'privacy'       => 'public',                // Optional: privacy of the document e.g. public.
			'menu_order'    => 0,                       // Optional:  Menu order.
			'date_created'  => bp_core_current_time(),  // The GMT time that this document was recorded.
			'date_modified' => bp_core_current_time(),  // The GMT time that this document was modified.
			'error_type'    => 'bool',
		),
		'document_add'
	);

	// Setup document to be added.
	$document                = new BP_Document( $r['id'] );
	$document->blog_id       = $r['blog_id'];
	$document->attachment_id = $r['attachment_id'];
	$document->user_id       = (int) $r['user_id'];
	$document->title         = $r['title'];
	$document->folder_id     = (int) $r['folder_id'];
	$document->group_id      = (int) $r['group_id'];
	$document->activity_id   = (int) $r['activity_id'];
	$document->privacy       = $r['privacy'];
	$document->menu_order    = $r['menu_order'];
	$document->date_created  = $r['date_created'];
	$document->date_modified = $r['date_modified'];
	$document->error_type    = $r['error_type'];

	// groups document always have privacy to `grouponly`.
	if ( ! empty( $document->privacy ) && ( in_array( $document->privacy, array( 'forums', 'message' ), true ) ) ) {
		$document->privacy = $r['privacy'];
	} elseif ( ! empty( $document->group_id ) ) {
		$document->privacy = 'grouponly';
	} elseif ( ! empty( $document->folder_id ) ) {
		$folder = new BP_Document_Folder( $document->folder_id );
		if ( ! empty( $folder ) ) {
			$document->privacy = $folder->privacy;
		}
	}

	if ( isset( $_POST ) && isset( $_POST['action'] ) && 'groups_get_group_members_send_message' === $_POST['action'] ) {
		$document->privacy = 'message';
	}

	// save document.
	$save = $document->save();

	if ( 'wp_error' === $r['error_type'] && is_wp_error( $save ) ) {
		return $save;
	} elseif ( 'bool' === $r['error_type'] && false === $save ) {
		return false;
	}

	// document is saved for attachment.
	update_post_meta( $document->attachment_id, 'bp_document_saved', true );

	/**
	 * Fires at the end of the execution of adding a new document item, before returning the new document item ID.
	 *
	 * @param object $document document object.
	 *
	 * @since BuddyBoss 1.4.0
	 */
	do_action( 'bp_document_add', $document );

	return $document->id;
}