<?php
/**
 * SEO Integrator class
 *
 * @package     AIContentGuide
 * @subpackage  AIContentGuide/includes
 */

// If this file is called directly, abort.
if (!defined('ABSPATH')) {
    exit;
}

/**
 * Class for integrating with popular SEO plugins.
 */
class FULGID_AICOGU_SEO_Integrator {

    /**
     * Detect installed SEO plugins.
     *
     * @return array Array of detected SEO plugins.
     */
    public function detect_seo_plugins() {
        $detected_plugins = array();
        
        // Check for Yoast SEO
        if (defined('WPSEO_VERSION')) {
            $detected_plugins['yoast_seo'] = 'Yoast SEO';
        }
        
        // Check for Rank Math
        if (class_exists('RankMath')) {
            $detected_plugins['rank_math'] = 'Rank Math SEO';
        }
        
        // Check for All in One SEO
        if (defined('AIOSEO_VERSION')) {
            $detected_plugins['all_in_one_seo'] = 'All in One SEO';
        }
        
        // Check for SEOPress
        if (defined('SEOPRESS_VERSION')) {
            $detected_plugins['seopress'] = 'SEOPress';
        }
        
        return $detected_plugins;
    }

    /**
     * Check if a post has noindex directive from SEO plugins.
     *
     * @param int $post_id The post ID.
     * @return bool True if post has noindex, false otherwise.
     */
    public function is_post_noindex($post_id) {
        // Check Yoast SEO
        if (defined('WPSEO_VERSION')) {
            $robots = get_post_meta($post_id, '_yoast_wpseo_meta-robots-noindex', true);
            if ('1' === $robots) {
                return true;
            }
        }
        
        // Check Rank Math
        if (class_exists('RankMath')) {
            $robots = get_post_meta($post_id, 'rank_math_robots', true);
            if (is_array($robots) && in_array('noindex', $robots)) {
                return true;
            }
        }
        
        // Check All in One SEO
        if (defined('AIOSEO_VERSION')) {
            $robots = get_post_meta($post_id, '_aioseo_robots_noindex', true);
            if ('1' === $robots || 'on' === $robots) {
                return true;
            }
        }
        
        // Check SEOPress
        if (defined('SEOPRESS_VERSION')) {
            $robots = get_post_meta($post_id, '_seopress_robots_index', true);
            if ('yes' === $robots) {
                return true;
            }
        }
        
        return false;
    }

    /**
     * Get meta description from SEO plugins.
     *
     * @param int $post_id The post ID.
     * @return string The meta description or empty string.
     */
    public function get_meta_description($post_id) {
        // Check Yoast SEO
        if (defined('WPSEO_VERSION')) {
            $desc = get_post_meta($post_id, '_yoast_wpseo_metadesc', true);
            if (!empty($desc)) {
                return $desc;
            }
        }
        
        // Check Rank Math
        if (class_exists('RankMath')) {
            $desc = get_post_meta($post_id, 'rank_math_description', true);
            if (!empty($desc)) {
                return $desc;
            }
        }
        
        // Check All in One SEO
        if (defined('AIOSEO_VERSION')) {
            $desc = get_post_meta($post_id, '_aioseo_description', true);
            if (!empty($desc)) {
                return $desc;
            }
        }
        
        // Check SEOPress
        if (defined('SEOPRESS_VERSION')) {
            $desc = get_post_meta($post_id, '_seopress_titles_desc', true);
            if (!empty($desc)) {
                return $desc;
            }
        }
        
        return '';
    }

    /**
     * Filter WP_Query arguments to exclude noindex posts.
     *
     * @param array $args WP_Query arguments.
     * @return array Modified arguments.
     */
    public function filter_query_args($args) {
        // For the specific purpose of llms.txt generation, we'll simply limit to posts with
        // a 'publish' status, which is a basic filter that won't trigger query warnings
        $args['post_status'] = 'publish';
        
        // Instead of doing complex queries, we'll filter posts after fetching
        add_filter('the_posts', array($this, 'filter_noindex_posts'), 10, 2);
        
        return $args;
    }

    /**
     * Filter out noindex posts after they've been fetched.
     *
     * @param array    $posts The array of retrieved posts.
     * @param WP_Query $query The WP_Query instance.
     * @return array Filtered array of posts.
     */
    public function filter_noindex_posts($posts, $query) {
        // Only apply this filter to our specific queries
        if (!isset($query->query_vars['fulgid_aicogu_query'])) {
            return $posts;
        }
        
        // Remove this filter to avoid infinite loops
        remove_filter('the_posts', array($this, 'filter_noindex_posts'), 10);
        
        if (empty($posts)) {
            return $posts;
        }
        
        $filtered_posts = array();
        
        foreach ($posts as $post) {
            // Skip posts with noindex directive
            if ($this->is_post_noindex($post->ID)) {
                continue;
            }
            
            $filtered_posts[] = $post;
        }
        
        return $filtered_posts;
    }

    /**
     * Get posts for a specific post type, with noindex filtering.
     *
     * @param string $post_type The post type.
     * @param int    $limit     Maximum number of posts to return.
     * @return array Array of post objects.
     */
    public function get_posts_for_llms_txt($post_type, $limit = 20) {
        $args = array(
            'post_type' => $post_type,
            'post_status' => 'publish',
            'posts_per_page' => $limit,
            'orderby' => 'date',
            'order' => 'DESC',
            'fulgid_aicogu_query' => true, // Custom flag to identify our queries
        );
        
        $posts = get_posts($args);
        
        return $posts;
    }
    
    /**
     * Get focus keywords from SEO plugins.
     *
     * @param int $post_id The post ID.
     * @return array Array of focus keywords.
     */
    public function get_focus_keywords($post_id) {
        $keywords = array();
        
        // Check Yoast SEO
        if (defined('WPSEO_VERSION')) {
            $focus_kw = get_post_meta($post_id, '_yoast_wpseo_focuskw', true);
            if (!empty($focus_kw)) {
                $keywords[] = $focus_kw;
            }
            
            // Check for Yoast SEO Premium additional keywords
            $focus_kw_additional = get_post_meta($post_id, '_yoast_wpseo_focuskeywords', true);
            if (!empty($focus_kw_additional) && is_array(json_decode($focus_kw_additional, true))) {
                $additional_kws = json_decode($focus_kw_additional, true);
                foreach ($additional_kws as $kw_data) {
                    if (isset($kw_data['keyword'])) {
                        $keywords[] = $kw_data['keyword'];
                    }
                }
            }
        }
        
        // Check Rank Math
        if (class_exists('RankMath')) {
            $focus_kw = get_post_meta($post_id, 'rank_math_focus_keyword', true);
            if (!empty($focus_kw)) {
                $kw_array = explode(',', $focus_kw);
                $keywords = array_merge($keywords, array_map('trim', $kw_array));
            }
        }
        
        // Return unique keywords
        return array_unique(array_filter($keywords));
    }
    
    /**
     * Add SEO keywords to the llms.txt file content.
     *
     * @param string $content Current content.
     * @param int $post_id Post ID.
     * @return string Modified content with keywords.
     */
    public function add_keywords_to_content($content, $post_id) {
        $keywords = $this->get_focus_keywords($post_id);
        
        if (!empty($keywords)) {
            $content .= " Keywords: " . implode(', ', $keywords);
        }
        
        return $content;
    }
}