<?php

declare(strict_types=1);

namespace AdsDestroyer\Admin;

use AdsDestroyer\Domain\XPathEngine;
use AdsDestroyer\Settings\OptionsRepository;
use AdsDestroyer\Logging\Logger;

/**
 * Output Buffer Service for AdsDestroyer plugin.
 * 
 * This class handles the output buffering functionality
 * to process and modify the HTML output before it's sent to the browser.
 * 
 * @since 1.0.0
 */
final class OutputBufferService {
    
    private XPathEngine $xpath_engine;
    private OptionsRepository $options_repository;
    private Logger $logger;
    
    public function __construct(XPathEngine $xpath_engine, OptionsRepository $options_repository, Logger $logger) {
        $this->xpath_engine = $xpath_engine;
        $this->options_repository = $options_repository;
        $this->logger = $logger;
    }
    
    /**
     * Initialize output buffering.
     */
    public function init(): void {
        // Start output buffering for frontend
        add_action('template_redirect', [$this, 'start_output_buffering']);
        
        // Start output buffering for admin pages
        add_action('admin_init', [$this, 'start_output_buffering']);
    }
    
    /**
     * Start output buffering.
     */
    public function start_output_buffering(): void {
        if (!$this->should_process_output()) {
            return;
        }
        
        // Start output buffering for processing HTML
        // Note: WordPress and other plugins may already have buffers active,
        // but we can still add our own buffer to the stack
        ob_start([$this, 'process_output']);
    }
    
    /**
     * Process the output buffer content.
     * 
     * @param string $content
     * @return string
     */
    public function process_output(string $content): string {
        if (empty($content) || $this->is_xml_content($content)) {
            return $content;
        }
        
        
        try {
            $rules = $this->options_repository->get_active_rules();
            
            // Check if selection mode is active (from sessionStorage via JavaScript)
            $is_selection_mode = $this->is_selection_mode_active();
            
            // Debug: log HTML size and check for WBCR
            $has_wbcr = strpos($content, 'id="WBCR"') !== false;
            $this->logger->debug('Output buffer received HTML', [
                'size' => strlen($content),
                'has_wbcr' => $has_wbcr,
                'has_wpbody' => strpos($content, 'id="wpbody-content"') !== false
            ]);
            
            return $this->xpath_engine->process_html($content, $rules, $is_selection_mode);
        } catch (\Exception $e) {
            // Log error but don't break the page
            if ($this->logger) {
                $this->logger->error('Error processing output', ['message' => $e->getMessage()]);
            } else {
                error_log('AdsDestroyer: Error processing output - ' . $e->getMessage());
            }
            return $content;
        }
    }
    
    /**
     * Check if output processing should be enabled.
     * 
     * @return bool
     */
    private function should_process_output(): bool {
        // Allow processing admin pages for block hiding
        // This enables hiding blocks on admin pages when rules are created there
        
        // Don't process AJAX requests
        if (wp_doing_ajax()) {
            return false;
        }
        
        // Don't process REST API requests
        if (defined('REST_REQUEST') && REST_REQUEST) {
            return false;
        }
        
        // Don't process if no rules are configured
        $rules = $this->options_repository->get_active_rules();
        if (empty($rules)) {
            return false;
        }
        
        return true;
    }
    
    /**
     * Check if content is XML (not HTML).
     * 
     * @param string $content
     * @return bool
     */
    private function is_xml_content(string $content): bool {
        $trimmed = trim($content);
        return str_starts_with($trimmed, '<?xml') || str_starts_with($trimmed, '<rss');
    }

    /**
     * Check if selection mode is active.
     * 
     * @return bool
     */
    private function is_selection_mode_active(): bool {
        // Don't process AJAX requests
        if (isset($_SERVER['HTTP_X_REQUESTED_WITH']) && $_SERVER['HTTP_X_REQUESTED_WITH'] === 'XMLHttpRequest') {
            return false;
        }
        
        // Check URL parameter for selection mode
        return isset($_GET['adsd_selection_mode_active']) && $_GET['adsd_selection_mode_active'] === '1';
    }
}