<?php
/**
 * WordPress.org directory access: listing metadata and, with the administrator's consent, a bounded,
 * read-only package scan.
 *
 * @package shouldcheck
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Looks up directory plugins. Never executes or extracts a package.
 */
final class ShouldCheck_Directory {

	const MAX_BYTES = 26214400; // 25 MB.

	/**
	 * Why the last inspection of a package failed, by cache key. Empty when it succeeded.
	 *
	 * @var array<string,string>
	 */
	private static $why = array();

	/**
	 * Cache key for a package scan. It includes the plugin version, so an upgrade of ShouldCheck
	 * never shows a scan made by an older scanner.
	 *
	 * @param string $slug    Plugin slug.
	 * @param string $version Package version.
	 * @return string
	 */
	public static function cache_key( $slug, $version ) {
		return 'shouldcheck_dirscan_' . md5( $slug . '|' . $version . '|' . ( defined( 'SHOULDCHECK_VERSION' ) ? SHOULDCHECK_VERSION : 'dev' ) );
	}

	/**
	 * Forget every cached package scan.
	 */
	public static function clear_cache() {
		global $wpdb;
		$wpdb->query( "DELETE FROM {$wpdb->options} WHERE option_name LIKE '\_transient\_shouldcheck\_dirscan\_%' OR option_name LIKE '\_transient\_timeout\_shouldcheck\_dirscan\_%'" ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery
	}

	/**
	 * Why a package could not be read, in one sentence. Empty when it was read or has not been tried.
	 *
	 * @param object $info Directory metadata.
	 * @return string
	 */
	public static function failure_reason( $info ) {
		$key = self::cache_key( (string) ( $info->slug ?? '' ), (string) ( $info->version ?? '' ) );
		return (string) ( self::$why[ $key ] ?? '' );
	}

	/**
	 * Directory listing metadata for a slug.
	 *
	 * @param string $slug Plugin slug.
	 * @return object|WP_Error
	 */
	public static function metadata( $slug ) {
		if ( ! ShouldCheck_Requirements::valid_slug( $slug ) ) {
			return new WP_Error( 'invalid_slug', 'Invalid WordPress.org plugin slug.' );
		}
		if ( ! function_exists( 'plugins_api' ) ) {
			require_once ABSPATH . 'wp-admin/includes/plugin-install.php';
		}
		$info = plugins_api(
			'plugin_information',
			array(
				'slug'   => $slug,
				'fields' => array(
					'sections'    => false,
					'description' => false,
					'reviews'     => false,
					'banners'     => false,
					'icons'       => false,
				),
			)
		);
		if ( is_wp_error( $info ) ) {
			return $info;
		}
		if ( ! is_object( $info ) || empty( $info->slug ) || $info->slug !== $slug ) {
			return new WP_Error( 'metadata_mismatch', 'WordPress.org returned unexpected plugin metadata.' );
		}
		return $info;
	}

	/**
	 * Read the published package and scan it, without installing or running anything.
	 *
	 * The download URL is built from the validated slug and version, never taken from the API
	 * response. Results are cached; failures are cached briefly so a slow network does not stall
	 * every page load.
	 *
	 * @param object $info Directory metadata.
	 * @return array{profile:array,header:array,php_minimum:?array}|null Null when the package could not be read.
	 */
	public static function inspect( $info ) {
		$slug    = (string) ( $info->slug ?? '' );
		$version = (string) ( $info->version ?? '' );
		if ( ! ShouldCheck_Requirements::valid_slug( $slug ) || ! preg_match( '/^[0-9][0-9A-Za-z._-]{0,39}$/D', $version ) ) {
			return null;
		}
		$key = self::cache_key( $slug, $version );
		// Downloading the package needs the administrator's consent. Without it, only the listing is read.
		if ( 'yes' !== ShouldCheck_Settings::get( 'package_lookup' ) ) {
			self::$why[ $key ] = 'Reading packages from WordPress.org is switched off.';
			return null;
		}
		$cached = get_transient( $key );
		if ( is_array( $cached ) ) {
			self::$why[ $key ] = (string) ( $cached['why'] ?? '' );
			return $cached['scan'] ?? null;
		}
		if ( ! function_exists( 'download_url' ) ) {
			require_once ABSPATH . 'wp-admin/includes/file.php';
		}
		$url   = 'https://downloads.wordpress.org/plugin/' . rawurlencode( $slug ) . '.' . rawurlencode( $version ) . '.zip';
		$limit = function ( $args, $request_url ) use ( $url ) {
			if ( $request_url === $url ) {
				$args['limit_response_size'] = self::MAX_BYTES;
				$args['redirection']         = 2;    // At most two redirects.
				$args['reject_unsafe_urls']  = true; // Refuse redirects to private or local addresses.
				$args['sslverify']           = true;
			}
			return $args;
		};
		add_filter( 'http_request_args', $limit, 10, 2 );
		$tmp = download_url( $url, 25 );
		remove_filter( 'http_request_args', $limit, 10 );

		$scan = null;
		$why  = '';
		if ( is_wp_error( $tmp ) ) {
			$msg = ShouldCheck_Views::plain( $tmp->get_error_message() );
			if ( false !== stripos( $msg, 'valid URL' ) ) {
				// WordPress says this when it will not use an address, usually because this server cannot look up the host name.
				$why = 'The download failed. WordPress refused the download address, usually because this server cannot look up downloads.wordpress.org.';
			} else {
				$why = 'The download failed: ' . sanitize_text_field( substr( $msg, 0, 160 ) );
			}
		} else {
			if ( (int) filesize( $tmp ) > self::MAX_BYTES ) {
				$why = 'The package is larger than the 25 MB limit.';
			} else {
				$got = ShouldCheck_Update_Diff::scan_zip( $tmp );
				if ( isset( $got['error'] ) ) {
					$why = 'The package could not be read as a plugin ZIP.';
				} else {
					$scan = $got;
				}
			}
			wp_delete_file( $tmp );
		}
		self::$why[ $key ] = $why;
		set_transient(
			$key,
			array(
				'scan' => $scan,
				'why'  => $why,
			),
			$scan ? 12 * HOUR_IN_SECONDS : 10 * MINUTE_IN_SECONDS
		);
		return $scan;
	}
}