<?php
/**
 * Resolve and remove every artifact that belongs to a page-cache entry.
 *
 * @package NBHPerformance
 */

namespace NBH\Performance\Modules\CacheEngine;

/**
 * Resolve and remove every artifact that belongs to a page-cache entry.
 */
final class CacheEntryFiles {
	/**
	 * Check that a path belongs to the plugin's cache page directory.
	 *
	 * Database rows and filesystem entries are not trusted deletion targets.
	 * Reject traversal and symlink escapes, including intermediate directories.
	 *
	 * @param string $path Absolute artifact path.
	 * @return bool
	 */
	public static function is_owned_cache_path( $path ) {
		if ( ! is_string( $path ) || '' === $path || false !== strpos( $path, "\0" ) || false !== strpos( $path, '://' ) ) {
			return false;
		}

		$path = wp_normalize_path( $path );
		$root = untrailingslashit( wp_normalize_path( WP_CONTENT_DIR . '/cache/nbh-performance/pages' ) );
		if ( 0 !== strpos( $path, $root . '/' ) || preg_match( '#(?:^|/)\.\.(?:/|$)#', $path ) || is_link( $path ) || is_link( $root ) ) {
			return false;
		}

		// Check every cache subdirectory and the cache-root ancestors: a missing
		// root could otherwise mask a symlink pointing outside wp-content.
		$directory = dirname( $path );
		$ancestor  = $directory;
		while ( 0 === strpos( $ancestor, wp_normalize_path( WP_CONTENT_DIR ) . '/' ) && $ancestor !== dirname( $ancestor ) ) {
			if ( is_link( $ancestor ) ) {
				return false;
			}
			$ancestor = dirname( $ancestor );
		}
		$existing  = $directory;
		while ( ! file_exists( $existing ) && ! is_link( $existing ) && $existing !== dirname( $existing ) ) {
			$existing = dirname( $existing );
		}
		if ( is_link( $existing ) ) {
			return false;
		}
		if ( is_dir( $root ) ) {
			$real_root = realpath( $root );
			$real_path = realpath( $existing );
			if ( false === $real_root || false === $real_path || ( $real_path !== $real_root && 0 !== strpos( $real_path, $real_root . DIRECTORY_SEPARATOR ) ) ) {
				return false;
			}
		} elseif ( is_link( $root ) ) {
			return false;
		}

		return true;
	}

	/**
	 * Check for a cache-entry HTML path under the owned root.
	 *
	 * @param string $path Cache HTML file.
	 * @return bool
	 */
	public static function is_owned_html_path( $path ) {
		return is_string( $path ) && 'index.html' === basename( $path ) && self::is_owned_cache_path( $path );
	}
	/**
	 * Return canonical artifact paths for a cache HTML file.
	 *
	 * @param string $html_file Canonical index.html path.
	 * @return array
	 */
	public static function paths( $html_file ) {
		$html_file = wp_normalize_path( (string) $html_file );
		$directory = dirname( $html_file );

		return array(
			'html'     => $html_file,
			'gzip'     => $html_file . '.gz',
			'brotli'   => $html_file . '.br',
			'metadata' => wp_normalize_path( $directory . '/metadata.json' ),
			'error'    => wp_normalize_path( $directory . '/error.json' ),
			'refresh'  => wp_normalize_path( $directory . '/refresh.lock' ),
			'lock'     => $html_file . '.lock',
		);
	}

	/**
	 * Delete all artifacts for one cache entry.
	 *
	 * @param string $html_file Canonical index.html path.
	 * @return bool
	 */
	public static function delete( $html_file ) {
		if ( ! self::is_owned_html_path( $html_file ) ) {
			return false;
		}

		$success = true;
		$paths   = self::paths( $html_file );

		foreach ( $paths as $path ) {
			if ( is_link( $path ) ) {
				$success = false;
				continue;
			}
			if ( is_file( $path ) && self::is_owned_cache_path( $path ) ) {
				wp_delete_file( $path );
				clearstatcache( true, $path );
				if ( is_file( $path ) ) {
					$success = false;
				}
			}
		}

		$directory = dirname( $paths['html'] );
		if ( is_dir( $directory ) ) {
			$contents = scandir( $directory );
			if ( is_array( $contents ) && 2 === count( $contents ) ) {
				// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
				\NBH\Performance\Modules\Core\Filesystem::rmdir( $directory );
			}
		}

		return $success;
	}
}