<?php
/**
 * WordPress Version check.
 *
 * @package advanced-analytics
 *
 * @since 4.9.0
 */

declare(strict_types=1);

namespace ADVAN\Checks\Security;

use ADVAN\Checks\Abstract_Check;

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

if ( ! class_exists( 'ADVAN\Checks\Security\WordPress_Version_Check' ) ) {

	/**
	 * WordPress Version check class.
	 *
	 * @since 4.9.0
	 */
	class WordPress_Version_Check extends Abstract_Check {

		/**
		 * Check identifier (slug).
		 *
		 * @var string Check identifier (slug).
		 *
		 * @since 4.9.0
		 */
		protected static string $id = 'wordpress-version';

		/**
		 * Check category.
		 *
		 * @var string Check category.
		 *
		 * @since 4.9.0
		 */
		protected static string $category = 'security';

		/**
		 * Check weight (1-10).
		 *
		 * @var int Check weight (1-10).
		 *
		 * @since 4.9.0
		 */
		protected static int $weight = 9;

		/**
		 * Check title (translatable).
		 *
		 * @return string Check title.
		 *
		 * @since 4.9.0
		 */
		public static function get_title(): string {
			return __( 'WordPress Version', '0-day-analytics' );
		}

		/**
		 * Check description (translatable).
		 *
		 * @return string Check description.
		 *
		 * @since 4.9.0
		 */
		public static function get_description(): string {
			return __( 'Checks if WordPress core is up to date.', '0-day-analytics' );
		}

		/**
		 * Run the check.
		 *
		 * @return array Check result.
		 *
		 * @since 4.9.0
		 */
		public static function run(): array {
			global $wp_version;

			$current_version = $wp_version;

			// Get the latest version from transient (populated by WordPress core).
			// This transient is set by WordPress when checking for updates.
			// In admin context, WordPress automatically checks for updates regularly.
			$latest_version = self::get_latest_version();

			$details = array(
				'current_version' => $current_version,
				'latest_version'  => $latest_version,
			);

			if ( ! $latest_version ) {
				return static::info(
					sprintf(
					/* translators: %s: WordPress version */
						__( 'Your site is running WordPress %s. We couldn\'t check for the latest version right now.', '0-day-analytics' ),
						$current_version
					),
					$details
				);
			}

			// Compare versions.
			$comparison = version_compare( $current_version, $latest_version );

			if ( $comparison >= 0 ) {
				return static::pass(
					sprintf(
					/* translators: %s: WordPress version */
						__( 'Your WordPress installation is up to date (version %s).', '0-day-analytics' ),
						$current_version
					),
					$details
				);
			}

			// Check how far behind we are.
			$current_parts = explode( '.', $current_version );
			$latest_parts  = explode( '.', $latest_version );

			$major_behind = ( $current_parts[0] ?? 0 ) < ( $latest_parts[0] ?? 0 );
			$minor_behind = ! $major_behind && ( ( $current_parts[1] ?? 0 ) < ( $latest_parts[1] ?? 0 ) );

			if ( $major_behind ) {
				return static::fail(
					'critical',
					sprintf(
					/* translators: 1: current version, 2: latest version */
						__( 'Your WordPress installation (version %1$s) is significantly outdated. The latest version is %2$s. Outdated WordPress versions are a common target for hackers.', '0-day-analytics' ),
						$current_version,
						$latest_version
					),
					__( 'Go to Dashboard → Updates and click "Update Now" to get the latest WordPress version. Always backup your site before updating.', '0-day-analytics' ),
					$details
				);
			}

			if ( $minor_behind ) {
				return static::fail(
					'high',
					sprintf(
					/* translators: 1: current version, 2: latest version */
						__( 'Your WordPress version (%1$s) is behind the latest release (%2$s). Minor updates often include important security fixes.', '0-day-analytics' ),
						$current_version,
						$latest_version
					),
					__( 'Go to Dashboard → Updates and update to the latest WordPress version. Minor updates are generally safe and include security fixes.', '0-day-analytics' ),
					$details
				);
			}

			// Just a patch version behind.
			return static::warning(
				sprintf(
				/* translators: 1: current version, 2: latest version */
					__( 'A newer version of WordPress (%2$s) is available. You\'re running %1$s.', '0-day-analytics' ),
					$current_version,
					$latest_version
				),
				__( 'Go to Dashboard → Updates to update WordPress. Keep your site updated for the best security.', '0-day-analytics' ),
				$details
			);
		}

		/**
		 * Get the latest WordPress version.
		 *
		 * Uses the update_core transient that WordPress core populates
		 * during its regular update checks. This transient is automatically
		 * refreshed by WordPress in admin context.
		 *
		 * @return string|false Latest version or false on failure.
		 *
		 * @since 4.9.0
		 */
		private static function get_latest_version() {
			// Get cached version info from WordPress core's update check.
			// This transient is populated by WordPress when checking for updates.
			$update_core = get_site_transient( 'update_core' );

			// If transient exists and has version info, return it.
			if ( isset( $update_core->updates[0]->version ) ) {
				return $update_core->updates[0]->version;
			}

			// If no transient exists yet and wp_version_check() is available,
			// trigger an update check. This function is loaded in admin context.
			if ( function_exists( 'wp_version_check' ) ) {
				wp_version_check();
				$update_core = get_site_transient( 'update_core' );

				if ( isset( $update_core->updates[0]->version ) ) {
					return $update_core->updates[0]->version;
				}
			}

			return false;
		}
	}
}