<?php
/**
 * Site scanner. Inspects the local WP install for migratable assets.
 *
 * @package Shiftora\Migration
 */

declare(strict_types=1);

namespace Shiftora\Migration;

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

/**
 * Sizes the local site's file stages for the wizard's scope step and the progress estimate.
 */
final class SiteScanner {

	/**
	 * @return array<string, mixed> `uploads_size_bytes`, plus whatever a registered file stage reports under its own id.
	 */
	public function scan(): array {
		$scan = [ 'uploads_size_bytes' => $this->uploads_size() ];

		/**
		 * Filters the scan, so a file stage added through `shiftora_file_stages` can
		 * report its items. Each item carries a `size_bytes`.
		 *
		 * @param array<string, mixed> $scan The uploads size, keyed `uploads_size_bytes`.
		 */
		$filtered = apply_filters( 'shiftora_site_scan', $scan );

		return is_array( $filtered ) ? array_merge( $filtered, $scan ) : $scan;
	}

	private function uploads_size(): int {
		$upload_dir = wp_upload_dir();
		$base       = $upload_dir['basedir'] ?? '';

		if ( ! $base || ! is_dir( $base ) ) {
			return 0;
		}

		return $this->dir_size( $base );
	}

		/**
		 * Directory size in bytes. Bounded to 10 levels and 200,000 files (a partial sum
		 * past that), cached in a transient for 60 seconds per path, symlinks not followed.
		 *
		 * @param string $path Absolute directory path.
		 */
	private function dir_size( string $path ): int {
		if ( ! is_dir( $path ) ) {
			return 0;
		}

		$cache_key = 'shiftora_dir_size_' . md5( $path );
		$cached    = get_transient( $cache_key );
		if ( false !== $cached ) {
			return (int) $cached;
		}

		$size       = 0;
		$file_count = 0;
		$max_files  = 200000;
		$max_depth  = 10;

		$inner_it = new \RecursiveDirectoryIterator(
			$path,
			\FilesystemIterator::SKIP_DOTS | \FilesystemIterator::UNIX_PATHS
		);
		$it = new \RecursiveIteratorIterator( $inner_it );
		$it->setMaxDepth( $max_depth );

		foreach ( $it as $file ) {
			if ( $file_count >= $max_files ) {
				break;
			}
			if ( $file->isFile() && ! $file->isLink() ) {
				$size += $file->getSize();
				$file_count++;
			}
		}

		set_transient( $cache_key, $size, 300 );

		return $size;
	}
}