<?php
/**
 * Main Plugin class.
 *
 * @package SpeedNest
 */

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

/**
 * Class WPSCO_Plugin
 *
 * Main plugin orchestrator. Initializes all modules.
 */
class WPSCO_Plugin {

    /**
     * Singleton instance.
     *
     * @var WPSCO_Plugin|null
     */
    private static $instance = null;

    /**
     * Module instances.
     *
     * @var array
     */
    private $modules = array();

    /**
     * Get singleton instance.
     *
     * @return WPSCO_Plugin
     */
    public static function get_instance() {
        if ( null === self::$instance ) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    /**
     * Constructor.
     */
    private function __construct() {
        $this->init_modules();
        $this->init_hooks();
    }

    /**
     * Initialize modules.
     */
    private function init_modules() {
        // Core modules (always loaded).
        $this->modules['conflict_detector'] = new WPSCO_Conflict_Detector();
        $this->modules['cache_manager']     = new WPSCO_Cache_Manager();
        $this->modules['cache_purger']      = new WPSCO_Cache_Purger();
        $this->modules['security']          = new WPSCO_Security();
        $this->modules['settings']          = new WPSCO_Settings();

        // Frontend optimization modules (loaded conditionally).
        if ( ! is_admin() && ! wpsco_get_setting( 'emergency_disable', false ) ) {
            if ( wpsco_get_setting( 'page_cache_enabled', false ) ) {
                $this->modules['page_cache'] = new WPSCO_Page_Cache();
            }
            if ( wpsco_get_setting( 'css_minify', false ) || wpsco_get_setting( 'css_combine', false ) || wpsco_get_setting( 'css_critical', false ) || wpsco_get_setting( 'css_async', false ) ) {
                $this->modules['css_optimizer'] = new WPSCO_CSS_Optimizer();
            }
            if ( wpsco_get_setting( 'js_minify', false ) || wpsco_get_setting( 'js_defer', false ) || wpsco_get_setting( 'js_delay', false ) ) {
                $this->modules['js_optimizer'] = new WPSCO_JS_Optimizer();
            }
            $this->modules['html_optimizer'] = new WPSCO_HTML_Optimizer();
            if ( wpsco_get_setting( 'lazy_load_images', false ) || wpsco_get_setting( 'add_missing_dimensions', false ) || wpsco_get_setting( 'lcp_image_preload', false ) ) {
                $this->modules['image_optimizer'] = new WPSCO_Image_Optimizer();
            }
            if ( wpsco_get_setting( 'font_display_swap', false ) || wpsco_get_setting( 'google_fonts_local', false ) || wpsco_get_setting( 'preload_fonts', false ) ) {
                $this->modules['font_optimizer'] = new WPSCO_Font_Optimizer();
            }
        }

        // WordPress optimizations (always check even on admin).
        $this->modules['wordpress_optimizer'] = new WPSCO_WordPress_Optimizer();

        // Integrations.
        if ( wpsco_is_woocommerce_active() ) {
            $this->modules['woocommerce'] = new WPSCO_WooCommerce();
        }
        if ( wpsco_is_elementor_active() ) {
            $this->modules['elementor'] = new WPSCO_Elementor();
        }
        if ( wpsco_get_setting( 'cloudflare_enabled', false ) ) {
            $this->modules['cloudflare'] = new WPSCO_Cloudflare();
        }
        if ( wpsco_get_setting( 'cdn_enabled', false ) ) {
            $this->modules['cdn'] = new WPSCO_CDN();
        }

        // Admin.
        if ( is_admin() ) {
            $this->modules['admin'] = new WPSCO_Admin();
        }

        // Diagnostics (loaded on demand via admin).
        // Database cleaner (loaded on demand via admin).
    }

    /**
     * Initialize hooks.
     */
    private function init_hooks() {
        // Admin bar.
        add_action( 'admin_bar_menu', array( $this, 'admin_bar_menu' ), 100 );

        // Auto cache purge hooks.
        add_action( 'save_post', array( $this, 'on_content_change' ), 10, 2 );
        add_action( 'delete_post', array( $this, 'on_content_change' ), 10 );
        add_action( 'wp_update_nav_menu', array( $this, 'on_menu_update' ) );
        add_action( 'update_option_sidebars_widgets', array( $this, 'on_widget_update' ) );
        add_action( 'switch_theme', array( $this, 'on_theme_change' ) );
        add_action( 'customize_save_after', array( $this, 'on_theme_change' ) );
        add_action( 'activated_plugin', array( $this, 'on_plugin_change' ) );
        add_action( 'deactivated_plugin', array( $this, 'on_plugin_change' ) );

        // Cron handlers.
        add_action( 'wpsco_cache_cleanup', array( $this, 'cron_cache_cleanup' ) );
        add_action( 'wpsco_expired_transients_cleanup', array( $this, 'cron_expired_transients' ) );
        add_action( 'wpsco_cache_warming', array( $this, 'cron_cache_warming' ) );

        // Plugin action links.
        add_filter( 'plugin_action_links_' . WPSCO_PLUGIN_BASENAME, array( $this, 'plugin_action_links' ) );
    }

    /**
     * Get a module instance.
     *
     * @param string $name Module name.
     * @return object|null
     */
    public function get_module( $name ) {
        return isset( $this->modules[ $name ] ) ? $this->modules[ $name ] : null;
    }

    /**
     * Admin bar menu.
     *
     * @param WP_Admin_Bar $admin_bar Admin bar instance.
     */
    public function admin_bar_menu( $admin_bar ) {
        if ( ! wpsco_current_user_can() ) {
            return;
        }

        $admin_bar->add_node( array(
            'id'    => 'wpsco',
            'title' => '<span class="ab-icon dashicons dashicons-performance" style="top:2px;"></span> ' . esc_html__( 'WP Speed', 'speednest' ),
            'href'  => admin_url( 'admin.php?page=wpsco-dashboard' ),
        ) );

        $items = array(
            'clear-cache'      => array(
                'title' => __( 'Clear Cache', 'speednest' ),
                'href'  => wp_nonce_url( admin_url( 'admin.php?page=wpsco-cache&action=clear_all' ), 'wpsco_cache_action' ),
            ),
            'clear-all'        => array(
                'title' => __( 'Purge Everything Possible', 'speednest' ),
                'href'  => wp_nonce_url( admin_url( 'admin.php?page=wpsco-cache&action=purge_everything' ), 'wpsco_cache_action' ),
            ),
            'clear-css'        => array(
                'title' => __( 'Clear CSS Cache', 'speednest' ),
                'href'  => wp_nonce_url( admin_url( 'admin.php?page=wpsco-cache&action=clear_css' ), 'wpsco_cache_action' ),
            ),
            'clear-js'         => array(
                'title' => __( 'Clear JS Cache', 'speednest' ),
                'href'  => wp_nonce_url( admin_url( 'admin.php?page=wpsco-cache&action=clear_js' ), 'wpsco_cache_action' ),
            ),
            'clear-html'       => array(
                'title' => __( 'Clear HTML Cache', 'speednest' ),
                'href'  => wp_nonce_url( admin_url( 'admin.php?page=wpsco-cache&action=clear_html' ), 'wpsco_cache_action' ),
            ),
            'clear-object'     => array(
                'title' => __( 'Clear Object Cache', 'speednest' ),
                'href'  => wp_nonce_url( admin_url( 'admin.php?page=wpsco-cache&action=clear_object' ), 'wpsco_cache_action' ),
            ),
            'reset-opcache'    => array(
                'title' => __( 'Reset OPcache', 'speednest' ),
                'href'  => wp_nonce_url( admin_url( 'admin.php?page=wpsco-cache&action=reset_opcache' ), 'wpsco_cache_action' ),
            ),
            'diagnostics'      => array(
                'title' => __( 'Run Diagnostics', 'speednest' ),
                'href'  => admin_url( 'admin.php?page=wpsco-diagnostics' ),
            ),
        );

        foreach ( $items as $id => $item ) {
            $admin_bar->add_node( array(
                'parent' => 'wpsco',
                'id'     => 'wpsco-' . $id,
                'title'  => esc_html( $item['title'] ),
                'href'   => esc_url( $item['href'] ),
            ) );
        }
    }

    /**
     * Handle content changes — targeted cache purge.
     *
     * @param int      $post_id Post ID.
     * @param WP_Post  $post    Post object (optional).
     */
    public function on_content_change( $post_id, $post = null ) {
        if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
            return;
        }

        if ( wp_is_post_revision( $post_id ) ) {
            return;
        }

        $purger = $this->get_module( 'cache_purger' );
        if ( ! $purger ) {
            return;
        }

        $post_obj  = $post ? $post : get_post( $post_id );
        $post_type = $post_obj ? $post_obj->post_type : '';

        // If a template/header/footer is updated, clear all page HTML & CSS caches.
        $is_template = in_array( $post_type, array(
            'elementor_library',
            'elementor-hf',
            'shopengine-template',
            'wp_template',
            'wp_template_part',
            'custom_css',
        ), true );

        if ( $is_template ) {
            $purger->purge_html_cache();
            $purger->purge_css_cache();
            wpsco_increment_cache_version();
            wpsco_log( sprintf( 'Global template updated (ID %d, type %s) — purged all HTML & CSS cache.', $post_id, $post_type ) );
            return;
        }

        // Purge specific post URL.
        $url = get_permalink( $post_id );
        if ( $url ) {
            $purger->purge_url( $url );
        }

        // Purge homepage.
        $purger->purge_url( home_url( '/' ) );

        // Purge category/archive pages.
        if ( $post_obj ) {
            $taxonomies = get_object_taxonomies( $post_obj->post_type );
            foreach ( $taxonomies as $taxonomy ) {
                $terms = get_the_terms( $post_id, $taxonomy );
                if ( $terms && ! is_wp_error( $terms ) ) {
                    foreach ( $terms as $term ) {
                        $term_link = get_term_link( $term );
                        if ( ! is_wp_error( $term_link ) ) {
                            $purger->purge_url( $term_link );
                        }
                    }
                }
            }
        }

        // Purge CSS/JS cache if settings changed.
        wpsco_log( sprintf( 'Cache purged for post ID %d', $post_id ) );
    }

    /**
     * Handle menu updates.
     */
    public function on_menu_update() {
        $purger = $this->get_module( 'cache_purger' );
        if ( $purger ) {
            $purger->purge_all_html();
        }
        wpsco_log( 'Cache purged: menu update' );
    }

    /**
     * Handle widget updates.
     */
    public function on_widget_update() {
        $purger = $this->get_module( 'cache_purger' );
        if ( $purger ) {
            $purger->purge_all_html();
        }
        wpsco_log( 'Cache purged: widget update' );
    }

    /**
     * Handle theme changes.
     */
    public function on_theme_change() {
        $purger = $this->get_module( 'cache_purger' );
        if ( $purger ) {
            $purger->purge_all();
        }
        wpsco_increment_cache_version();
        wpsco_log( 'Full cache purge: theme change' );
    }

    /**
     * Handle plugin changes.
     */
    public function on_plugin_change() {
        $purger = $this->get_module( 'cache_purger' );
        if ( $purger ) {
            $purger->purge_all();
        }
        // Re-detect conflicts.
        $detector = $this->get_module( 'conflict_detector' );
        if ( $detector ) {
            $detector->detect_all();
        }
        wpsco_log( 'Full cache purge: plugin change' );
    }

    /**
     * Cron: cache cleanup.
     */
    public function cron_cache_cleanup() {
        $purger = $this->get_module( 'cache_purger' );
        if ( $purger ) {
            $purger->cleanup_expired_html_cache();
        }
    }

    /**
     * Cron: expired transients.
     */
    public function cron_expired_transients() {
        if ( function_exists( 'delete_expired_transients' ) ) {
            delete_expired_transients( true );
            return;
        }

        global $wpdb;
        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Fallback direct query required for bulk deletion of expired transients.
        $wpdb->query(
            $wpdb->prepare(
                "DELETE a, b FROM {$wpdb->options} a
                INNER JOIN {$wpdb->options} b ON b.option_name = CONCAT('_transient_timeout_', SUBSTRING(a.option_name, 12))
                WHERE a.option_name LIKE %s AND b.option_value < %d",
                $wpdb->esc_like( '_transient_' ) . '%',
                time()
            )
        );
    }

    /**
     * Cron: cache warming.
     */
    public function cron_cache_warming() {
        if ( ! wpsco_get_setting( 'cache_warming_enabled', false ) ) {
            return;
        }

        $urls        = $this->get_cache_warming_urls();
        $concurrency = (int) wpsco_get_setting( 'cache_warming_concurrency', 2 );
        $concurrency = max( 1, min( 5, $concurrency ) );
        $batch_size  = $concurrency;
        $batches     = array_chunk( $urls, $batch_size );

        foreach ( $batches as $batch ) {
            foreach ( $batch as $url ) {
                wp_remote_get( $url, array(
                    'timeout'    => 10,
                    'blocking'   => false,
                    'user-agent' => 'WPSpeedCacheOptimizer/CacheWarmer',
                ) );
            }
            // Small delay between batches.
            usleep( 500000 );
        }
    }

    /**
     * Get URLs for cache warming.
     *
     * @return array
     */
    private function get_cache_warming_urls() {
        $urls = array( home_url( '/' ) );

        // Get recent pages.
        $pages = get_posts( array(
            'post_type'      => 'page',
            'post_status'    => 'publish',
            'posts_per_page' => 20,
            'fields'         => 'ids',
        ) );
        foreach ( $pages as $page_id ) {
            $urls[] = get_permalink( $page_id );
        }

        // Get recent posts.
        $posts = get_posts( array(
            'post_type'      => 'post',
            'post_status'    => 'publish',
            'posts_per_page' => 20,
            'fields'         => 'ids',
        ) );
        foreach ( $posts as $post_id ) {
            $urls[] = get_permalink( $post_id );
        }

        // WooCommerce products.
        if ( wpsco_is_woocommerce_active() ) {
            $products = get_posts( array(
                'post_type'      => 'product',
                'post_status'    => 'publish',
                'posts_per_page' => 30,
                'fields'         => 'ids',
            ) );
            foreach ( $products as $product_id ) {
                $urls[] = get_permalink( $product_id );
            }
        }

        return array_unique( $urls );
    }

    /**
     * Plugin action links.
     *
     * @param array $links Existing links.
     * @return array
     */
    public function plugin_action_links( $links ) {
        $custom = array(
            '<a href="' . esc_url( admin_url( 'admin.php?page=wpsco-dashboard' ) ) . '">' . esc_html__( 'Dashboard', 'speednest' ) . '</a>',
            '<a href="' . esc_url( admin_url( 'admin.php?page=wpsco-settings' ) ) . '">' . esc_html__( 'Settings', 'speednest' ) . '</a>',
        );
        return array_merge( $custom, $links );
    }
}