<?php
namespace ActiveTwist\SEO\Features;

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

use ActiveTwist\SEO\Settings\Options;

class LlmsController
{
    const OPTION_KEY_LLMS = 'llms_txt_content';

    public function init()
    {
        add_action('init', [$this, 'add_rewrites']);
        add_filter('query_vars', [$this, 'add_query_vars']);
        add_action('template_redirect', [$this, 'render_llms_txt'], 1);
        add_action('admin_post_at_seo_save_llms', [$this, 'handle_save']);
        add_action('admin_post_at_seo_reset_llms', [$this, 'handle_reset']);
    }

    public function add_rewrites()
    {
        add_rewrite_rule('^llms\.txt$', 'index.php?at_llms=1', 'top');
    }

    public function add_query_vars($vars)
    {
        $vars[] = 'at_llms';
        return $vars;
    }

    public function render_llms_txt()
    {
        $show = get_query_var('at_llms');

        // Fallback: Check REQUEST_URI
        if (!$show) {
            $request_uri = isset($_SERVER['REQUEST_URI']) ? sanitize_text_field(wp_unslash($_SERVER['REQUEST_URI'])) : '';
            $path = trim((string) wp_parse_url($request_uri, PHP_URL_PATH), '/');
            $home_path = trim((string) wp_parse_url(home_url(), PHP_URL_PATH), '/');
            if (!empty($home_path) && strpos($path, $home_path) === 0) {
                $path = trim(substr($path, strlen($home_path)), '/');
            }
            if ($path === 'llms.txt') {
                $show = true;
            }
        }

        if (!$show) {
            return;
        }

        $content = Options::get(self::OPTION_KEY_LLMS);

        if (empty($content)) {
            $content = self::get_default_content();
        }

        status_header(200);
        header('Content-Type: text/plain; charset=utf-8');
        header('X-Robots-Tag: noindex, follow'); // Should LLMs.txt be indexed? Usually yes, but depends on strategy. Let's allow simple indexing.
        // Actually, let's stick to standard practice. LLMs.txt is for bots.

        // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- llms.txt is plain text output.
        echo $content;
        exit;
    }

    public function handle_save()
    {
        if (!current_user_can('manage_options')) {
            wp_die('Unauthorized');
        }

        check_admin_referer('at_seo_save_files', 'at_seo_files_nonce');

        $content = isset($_POST['at_seo_llms_content']) ? sanitize_textarea_field(wp_unslash($_POST['at_seo_llms_content'])) : '';

        $options = Options::get_all();
        $options[self::OPTION_KEY_LLMS] = $content;
        update_option(Options::OPTION_NAME, $options);

        wp_safe_redirect(add_query_arg(['page' => 'active-twist-seo-files', 'tab' => 'llms', 'updated' => '1'], admin_url('admin.php')));
        exit;
    }

    public function handle_reset()
    {
        if (!current_user_can('manage_options')) {
            wp_die('Unauthorized');
        }

        check_admin_referer('at_seo_reset_llms', 'at_seo_min_nonce');

        $options = Options::get_all();
        unset($options[self::OPTION_KEY_LLMS]);
        update_option(Options::OPTION_NAME, $options);

        wp_safe_redirect(add_query_arg(['page' => 'active-twist-seo-files', 'tab' => 'llms', 'reset' => '1'], admin_url('admin.php')));
        exit;
    }

    public static function get_default_content()
    {
        $site_name = get_bloginfo('name');
        $site_desc = get_bloginfo('description');
        $sitemap_url = home_url('/sitemap.xml');

        return "# {$site_name}\n\n> {$site_desc}\n\n## Sitemaps\n\n- {$sitemap_url}\n\n## Documentation\n\n- [Optional: Add link to documentation index]\n";
    }
}