Admin Bar Notification Dropdown Menu

`function bp_messages_notifications_menu() {
	global $wp_admin_bar;

if ( ! is_user_logged_in() ) {
		return false;
	}
	$messages = bp_get_total_unread_messages_count( bp_loggedin_user_id(), 'object' );
	$count         = ! empty( $messages ) ? count( $messages ) : 0;
	$alert_class   = (int) $count > 0 ? 'pending-count alert' : 'count no-alert';
	$menu_title    = '<span class="ab-icon"></span><span id="ab-pending-notifications" class="' . $alert_class . '">' . number_format_i18n( $count ) . '</span>';
	$menu_link     = trailingslashit( bp_loggedin_user_domain() . bp_get_messages_slug() );

/** Add the top-level Notifications button **/
$wp_admin_bar->add_menu( array(
		'parent'    => 'top-secondary',
		'id'        => 'messages-personal-li',
		'title'     => $menu_title,
		'href'      => $menu_link,
) );

$sender_name = bp_core_get_user_displayname( $sender_id );
$message   = new BP_Messages_Message( $item_id );
$thread_id = $message->thread_id;
$title     = sprintf( __( '%s sent you a new private message', 'buddypress' ), $sender_name );

if ( bp_message_thread_has_unread() ) {
foreach ( (array) $messages as $message ) {
$wp_admin_bar->add_menu( array(
'parent' => 'messages-personal-li',
'id'     => 'message-threads',
'title'  => $title,
'href'   => $menu_link,
) );
}
} else {
$wp_admin_bar->add_menu( array(
'parent' => 'messages-personal-li',
'id' => 'no-notifications',
'title' => __( 'No new messages', 'buddypress' ),
) );
}

return;
}
add_action( 'admin_bar_menu', 'bp_messages_notifications_menu', 90 );`