opticore/includes/class-cache-manager.php

<?php
/**
 * Cache Manager Class
 * 
 * Handles page caching and cache management
 */

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

class OptiCore_Cache_Manager {
    
    private static $instance = null;
    private $cache_dir;
    private $cache_duration = 3600; // 1 hour
    
    public static function get_instance() {
        if (null === self::$instance) {
            self::$instance = new self();
        }
        return self::$instance;
    }
    
    private function __construct() {
        $this->cache_dir = WP_CONTENT_DIR . '/cache/opticore';
    }
    
    public function init() {
        // Create cache directory if not exists
        if (!file_exists($this->cache_dir)) {
            wp_mkdir_p($this->cache_dir);
        }
        
        // Only cache for non-logged-in users
        if (!is_user_logged_in() && !is_admin()) {
            add_action('template_redirect', array($this, 'serve_cached_page'), 1);
            add_action('shutdown', array($this, 'cache_page'), 999);
            add_action('wp_footer', array($this, 'add_cache_comment'), 999);
        }
        
        // Clear cache on post update
        add_action('save_post', array($this, 'clear_page_cache'));
        add_action('comment_post', array($this, 'clear_page_cache'));
    }
    
    /**
     * Add cache comment to footer
     */
    public function add_cache_comment() {
        if ($this->should_skip_cache()) {
            return;
        }
        
        echo "\n" . '<!-- OptiCore Cache Active: Page will be cached on first visit -->' . "\n";
    }
    
    /**
     * Get cache key for current request
     */
    private function get_cache_key() {
        $url = $_SERVER['REQUEST_URI'];
        $device = wp_is_mobile() ? 'mobile' : 'desktop';
        return md5($url . $device);
    }
    
    /**
     * Get cache file path
     */
    private function get_cache_file() {
        $key = $this->get_cache_key();
        return $this->cache_dir . '/' . $key . '.html';
    }
    
    /**
     * Serve cached page if available
     */
    public function serve_cached_page() {
        // Skip cache for certain conditions
        if ($this->should_skip_cache()) {
            return;
        }
        
        $cache_file = $this->get_cache_file();
        
        if (file_exists($cache_file)) {
            $cache_time = filemtime($cache_file);
            
            // Check if cache is still valid
            if ((time() - $cache_time) < $this->cache_duration) {
                $content = file_get_contents($cache_file);
                echo $content;
                echo '<!-- Cached by OptiCore at ' . date('Y-m-d H:i:s', $cache_time) . ' -->';
                exit;
            }
        }
    }
    
    /**
     * Cache the current page
     */
    public function cache_page() {
        if ($this->should_skip_cache()) {
            return;
        }
        
        // Get buffer content
        $content = '';
        $levels = ob_get_level();
        
        for ($i = 0; $i < $levels; $i++) {
            $content = ob_get_contents();
            if (!empty($content)) {
                break;
            }
        }
        
        if (empty($content) || strlen($content) < 255) {
            return;
        }
        
        $cache_file = $this->get_cache_file();
        
        // Create directory if it doesn't exist
        if (!file_exists($this->cache_dir)) {
            wp_mkdir_p($this->cache_dir);
        }
        
        // Add cache comment
        $content .= "\n" . '<!-- Cached by OptiCore at ' . date('Y-m-d H:i:s') . ' -->';
        
        // Save cache file
        file_put_contents($cache_file, $content);
        
        // Also output the comment
        echo "\n" . '<!-- Cached by OptiCore at ' . date('Y-m-d H:i:s') . ' -->';
    }
    
    /**
     * Check if we should skip caching
     */
    private function should_skip_cache() {
        // Skip for logged-in users
        if (is_user_logged_in()) {
            return true;
        }
        
        // Skip for admin area
        if (is_admin()) {
            return true;
        }
        
        // Skip for POST requests
        if ($_SERVER['REQUEST_METHOD'] === 'POST') {
            return true;
        }
        
        // Skip for AJAX requests
        if (defined('DOING_AJAX') && DOING_AJAX) {
            return true;
        }
        
        // Skip for certain query strings
        if (!empty($_GET) && !isset($_GET['utm_source'])) {
            return true;
        }
        
        return false;
    }
    
    /**
     * Clear page cache
     */
    public function clear_page_cache($post_id = null) {
        if (!file_exists($this->cache_dir)) {
            return;
        }
        
        $files = glob($this->cache_dir . '/*.html');
        foreach ($files as $file) {
            if (is_file($file)) {
                unlink($file);
            }
        }
    }
    
    /**
     * Get cache statistics
     */
    public function get_cache_stats() {
        $stats = array(
            'total_files' => 0,
            'total_size' => 0,
        );
        
        if (!file_exists($this->cache_dir)) {
            return $stats;
        }
        
        $files = glob($this->cache_dir . '/*.html');
        $stats['total_files'] = count($files);
        
        foreach ($files as $file) {
            if (is_file($file)) {
                $stats['total_size'] += filesize($file);
            }
        }
        
        return $stats;
    }
}