<?php
/**
 * Names for database dumps that sit under the uploads directory.
 *
 * @package Shiftora\Support
 */

declare(strict_types=1);

namespace Shiftora\Support;

// Prevent direct file access.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Backups and exports live in uploads, which the web server serves. Apache
 * obeys the folder's deny rule; nginx ignores .htaccess entirely, so on nginx a
 * dump is public to anyone who can name it. A timestamp plus a few random
 * characters is nameable by brute force, so every dump gets 128 random bits on
 * disk. People still see the readable part: the suffix is stripped for display
 * and for the downloaded file's name.
 */
final class PrivateFileName {

	/** Matches the suffix make() appends, so display() never strips anything else. */
	private const SUFFIX = '/-[0-9a-f]{32}(?=\.sql(\.gz)?$)/';

	/**
	 * A dump name nobody can guess, e.g. "shiftora-export-20261016-101500-<32 hex>.sql".
	 *
	 * @param string $stem Readable part, without extension.
	 * @param string $ext  Extension including the dot, ".sql" or ".sql.gz".
	 */
	public static function make( string $stem, string $ext ): string {
		return $stem . '-' . bin2hex( random_bytes( 16 ) ) . $ext;
	}

	/** The name to show or download as: the same file, minus its random suffix. */
	public static function display( string $basename ): string {
		return (string) preg_replace( self::SUFFIX, '', $basename );
	}
}