<?php
/**
 * Current local plugin candidates for one explicitly selected checksum request.
 *
 * @package Px320\SiteAudit
 */

declare(strict_types=1);

namespace Px320\SiteAudit\External;

use Px320\SiteAudit\Checks\Components\ComponentEvidenceSanitizer;
use Px320\SiteAudit\Filesystem\WordPressPathProvider;
use Px320\SiteAudit\Security\LocalHashKey;

final class PluginChecksumInventory {
	private const MAX_PLUGINS = 500;
	private string $hash_key;
	private ComponentEvidenceSanitizer $sanitizer;
	private WordPressPathProvider $paths;

	public function __construct( ?string $hash_key = null, ?WordPressPathProvider $paths = null ) {
		$this->hash_key  = $hash_key ?? ( new LocalHashKey() )->derive();
		$this->sanitizer = new ComponentEvidenceSanitizer( $this->hash_key );
		$this->paths     = $paths ?? new WordPressPathProvider();
	}

	/**
	 * @return list<array{id:string,name:string,version:string,state:string}>
	 */
	public function candidates(): array {
		return array_map(
			static function ( array $plugin ): array {
				return array(
					'id'      => $plugin['id'],
					'name'    => $plugin['name'],
					'version' => $plugin['version'],
					'state'   => $plugin['state'],
				);
			},
			$this->inventory()
		);
	}

	/**
	 * Resolve exactly one opaque current selection; no slug, version or path is
	 * accepted from REST input.
	 *
	 * @return array{id:string,slug:string,name:string,version:string,state:string,root:string}
	 */
	public function selected( string $opaque_id ): array {
		if ( 1 !== preg_match( '/^plugin_[a-f0-9]{24}$/D', $opaque_id ) ) {
			throw new \InvalidArgumentException( 'plugin_checksum_selection_invalid' );
		}
		foreach ( $this->inventory() as $plugin ) {
			if ( hash_equals( $plugin['id'], $opaque_id ) ) {
				return $plugin;
			}
		}

		throw new \InvalidArgumentException( 'plugin_checksum_selection_unavailable' );
	}

	/**
	 * @return list<array{id:string,slug:string,name:string,version:string,state:string,root:string}>
	 */
	private function inventory(): array {
		if ( ! function_exists( 'get_plugins' ) ) {
			require_once $this->paths->core_file( 'wp-admin/includes/plugin.php' );
		}
		$active         = array_map( 'strval', (array) get_option( 'active_plugins', array() ) );
		$network_active = is_multisite() ? array_keys( (array) get_site_option( 'active_sitewide_plugins', array() ) ) : array();
		$self           = defined( 'PX320_SITE_AUDIT_FILE' ) ? plugin_basename( PX320_SITE_AUDIT_FILE ) : '';
		$plugins        = array();
		foreach ( array_slice( get_plugins(), 0, self::MAX_PLUGINS, true ) as $file => $headers ) {
			$file = (string) $file;
			if ( '' !== $self && $file === $self ) {
				continue;
			}
			$directory = dirname( $file );
			if ( '.' === $directory ) {
				continue;
			}
			$slug        = '.' === $directory ? basename( $file, '.php' ) : basename( $directory );
			$plugin_path = $this->paths->plugin_path( $directory );
			$root        = realpath( $plugin_path );
			$version     = isset( $headers['Version'] ) && is_string( $headers['Version'] ) ? $this->sanitizer->version( $headers['Version'] ) : 'unknown';
			if ( false === $root || is_link( $plugin_path ) || 1 !== preg_match( '/^[a-z0-9][a-z0-9-]{0,99}$/D', $slug ) || 'unknown' === $version ) {
				continue;
			}
			$root = wp_normalize_path( $root );
			if ( 0 !== strpos( $root . '/', rtrim( wp_normalize_path( $this->paths->plugins_root() ), '/' ) . '/' ) ) {
				continue;
			}
			$state     = in_array( $file, $network_active, true ) ? 'network_active' : ( in_array( $file, $active, true ) ? 'active' : 'inactive' );
			$identity  = $slug . '|' . $version . '|' . $file;
			$plugins[] = array(
				'id'      => 'plugin_' . substr( hash_hmac( 'sha256', $identity, $this->hash_key ), 0, 24 ),
				'slug'    => $slug,
				'name'    => $this->sanitizer->text( isset( $headers['Name'] ) && is_string( $headers['Name'] ) ? $headers['Name'] : $slug ),
				'version' => $version,
				'state'   => $state,
				'root'    => $root,
			);
		}
		usort(
			$plugins,
			static function ( array $left, array $right ): int {
				return array( $left['name'], $left['version'], $left['id'] ) <=> array( $right['name'], $right['version'], $right['id'] );
			}
		);

		return $plugins;
	}
}