<?php
/**
 * Wires the storage classes to WordPress: options, constants, salts.
 *
 * @package Fitzaro
 */

namespace Fitzaro\Storage;

defined( 'ABSPATH' ) || exit;

/**
 * The chosen folder is remembered in an option, so it never moves between requests
 * (a cron run has no DOCUMENT_ROOT and would otherwise pick a different place).
 */
final class Storage {

	public const OPTION_LOCATION = 'fitzaro_storage';
	public const OPTION_SUFFIX   = 'fitzaro_storage_suffix';

	/**
	 * Where photos are stored. FITZARO_STORAGE_DIR always wins; otherwise the remembered folder,
	 * otherwise a fresh choice that is then remembered.
	 */
	public static function location(): Location {
		$override = defined( 'FITZARO_STORAGE_DIR' ) ? (string) constant( 'FITZARO_STORAGE_DIR' ) : null;

		if ( null === $override ) {
			$saved = get_option( self::OPTION_LOCATION );
			if ( is_array( $saved ) && isset( $saved['path'], $saved['mode'] ) && self::is_writable_dir( (string) $saved['path'] ) ) {
				return Location::remembered( (string) $saved['path'], (string) $saved['mode'] );
			}
		}

		$document_root = isset( $_SERVER['DOCUMENT_ROOT'] ) ? (string) wp_unslash( $_SERVER['DOCUMENT_ROOT'] ) : ''; // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- A filesystem path set by the web server, only compared against other paths.

		$location = Location::choose(
			$override,
			ABSPATH,
			$document_root,
			(string) wp_upload_dir( null, false )['basedir'],
			self::suffix(),
			array( self::class, 'is_writable_dir' )
		);

		// Remember only a choice made in a web request: without DOCUMENT_ROOT (WP-CLI, system cron) the
		// outside folder cannot be proven safe, and an uploads choice saved now would stick for good.
		// Files are first written by a web upload, so a later job always finds the remembered folder.
		if ( $location->is_usable() && null === $override && '' !== $document_root ) {
			update_option(
				self::OPTION_LOCATION,
				array(
					'path' => $location->path(),
					'mode' => $location->mode(),
				),
				true
			);
		}

		return $location;
	}

	/**
	 * The file store, or null when no folder is usable.
	 */
	public static function store(): ?FileStore {
		$location = self::location();

		return $location->is_usable() ? new FileStore( $location->path() ) : null;
	}

	/**
	 * Signer for file links. The key is derived from the site's auth salt, so it differs per site
	 * and changes when the salts are rotated (which invalidates all outstanding links).
	 */
	public static function signer(): UrlSigner {
		return new UrlSigner( hash_hmac( 'sha256', 'fitzaro-file-links', wp_salt( 'auth' ) ) );
	}

	/**
	 * Whether a path is an existing, writable directory.
	 *
	 * @param string $path Absolute path.
	 */
	public static function is_writable_dir( string $path ): bool {
		return is_dir( $path ) && wp_is_writable( $path );
	}

	/**
	 * Random lowercase suffix for the uploads fallback folder, created once per site.
	 */
	private static function suffix(): string {
		$suffix = (string) get_option( self::OPTION_SUFFIX, '' );

		if ( 1 !== preg_match( '/^[a-z0-9]{6,32}$/', $suffix ) ) {
			$suffix = strtolower( wp_generate_password( 16, false, false ) );
			update_option( self::OPTION_SUFFIX, $suffix, false );
		}

		return $suffix;
	}
}