<?php
namespace BavarianRankEngine\Features;

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

class RobotsTxt {
	private const OPTION_KEY = 'bre_robots_settings';

	public const KNOWN_BOTS = array(
		'GPTBot'            => 'OpenAI GPTBot',
		'ClaudeBot'         => 'Anthropic ClaudeBot',
		'Google-Extended'   => 'Google Extended (Bard/Gemini Training)',
		'PerplexityBot'     => 'Perplexity AI',
		'CCBot'             => 'Common Crawl (CCBot)',
		'Applebot-Extended' => 'Apple AI (Applebot-Extended)',
		'Bytespider'        => 'ByteDance Bytespider',
		'DataForSeoBot'     => 'DataForSEO Bot',
		'ImagesiftBot'      => 'Imagesift Bot',
		'omgili'            => 'Omgili Bot',
		'Diffbot'           => 'Diffbot',
		'FacebookBot'       => 'Meta FacebookBot',
		'Amazonbot'         => 'Amazon Amazonbot',
	);

	public function register(): void {
		add_filter( 'robots_txt', array( $this, 'append_rules' ), 20, 2 );
	}

	public function append_rules( string $output, bool $public ): string {
		$settings = self::getSettings();
		$blocked  = $settings['blocked_bots'] ?? array();

		foreach ( $blocked as $bot ) {
			if ( isset( self::KNOWN_BOTS[ $bot ] ) ) {
				$output .= "\nUser-agent: {$bot}\nDisallow: /\n";
			}
		}

		return $output;
	}

	public static function getSettings(): array {
		$saved = get_option( self::OPTION_KEY, array() );
		return array_merge(
			array( 'blocked_bots' => array() ),
			is_array( $saved ) ? $saved : array()
		);
	}
}