<?php
declare(strict_types=1);

namespace Unsupervised\Schedular\Auth;

/**
 * Resolves a person's public-facing name for display. Prefers their real name
 * (first + last), then their nickname — deliberately avoiding the account's
 * login/username, which `display_name` can otherwise expose.
 */
class UserName {

	/**
	 * The display name for a user: "First Last" when a real name is set,
	 * otherwise the WordPress nickname. Falls back to the numeric id (or an empty
	 * string when none is given) when the user cannot be loaded or has no name.
	 */
	public static function format( ?\WP_User $user, int $fallbackId = 0 ): string {
		if ( ! $user instanceof \WP_User ) {
			return $fallbackId > 0 ? (string) $fallbackId : '';
		}

		$full = trim( $user->first_name . ' ' . $user->last_name );
		if ( '' !== $full ) {
			return $full;
		}

		$nickname = trim( $user->nickname );
		if ( '' !== $nickname ) {
			return $nickname;
		}

		return $fallbackId > 0 ? (string) $fallbackId : '';
	}
}