<?php
/**
 * Robots control: per-post robots meta, archive/global rules and a full
 * robots.txt editor.
 *
 * @package AiRankSuite
 */

declare(strict_types=1);

namespace AiRankSuite\Modules\Robots;

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

use AiRankSuite\Container;
use AiRankSuite\Contracts\ModuleInterface;
use AiRankSuite\Rest\RestController;
use AiRankSuite\Support\Options;
use WP_REST_Request;
use WP_REST_Response;
use AiRankSuite\Support\Guard;

final class RobotsModule extends RestController implements ModuleInterface {

	/**
	 * Directives a user can set per post.
	 *
	 * @var array<int, string>
	 */
	public const DIRECTIVES = array( 'noindex', 'nofollow', 'noarchive', 'nosnippet', 'noimageindex' );

	public function id(): string {
		return 'robots';
	}

	/** @return array<string, mixed> */
	public static function defaults(): array {
		return array(
			'noindex_author'     => false,
			'noindex_date'       => true,
			'noindex_search'     => true,
			'noindex_paginated'  => false,
			'noindex_attachment' => true,
			'noindex_password'   => true,
			'attachment_parent'  => true, // Redirect attachment pages to their parent post.
			'max_snippet'        => -1,
			'max_image_preview'  => 'large',
			'max_video_preview'  => -1,
			'robots_txt_custom'  => '',
			'robots_txt_enabled' => false,
		);
	}

	public function register( Container $container ): void {}

	public function boot( Container $container ): void {
		add_action( 'rest_api_init', array( $this, 'routes' ) );
		Guard::filter( 'wp_robots', array( $this, 'robots' ), 20 );
		Guard::action( 'template_redirect', array( $this, 'attachment_redirect' ), 2 );
		Guard::filter( 'robots_txt', array( $this, 'robots_txt' ), 30 );
	}

	/**
	 * Merge our directives into WordPress' robots meta tag.
	 *
	 * @param array<string, mixed> $robots Existing directives.
	 * @return array<string, mixed>
	 */
	public function robots( array $robots ): array {
		$settings = $this->settings();

		if ( is_singular() ) {
			$post = get_queried_object();
			if ( $post instanceof \WP_Post ) {
				$stored = get_post_meta( $post->ID, '_airanksuite_robots', true );
				$stored = is_array( $stored ) ? $stored : array();
				foreach ( self::DIRECTIVES as $directive ) {
					if ( in_array( $directive, $stored, true ) ) {
						$robots[ $directive ] = true;
						if ( 'noindex' === $directive ) {
							unset( $robots['index'] );
						}
					}
				}
			}
		}

		// Password-protected content must not appear in search results or
		// AI training sets — the content behind it is not public.
		if ( is_singular() && ! empty( $settings['noindex_password'] ) && post_password_required() ) {
			$robots['noindex'] = true;
			unset( $robots['index'] );
		}

		$archive_rules = array(
			'noindex_author'     => is_author(),
			'noindex_date'       => is_date(),
			'noindex_search'     => is_search(),
			'noindex_attachment' => is_attachment(),
			'noindex_paginated'  => is_paged(),
		);
		foreach ( $archive_rules as $key => $matches ) {
			if ( $matches && ! empty( $settings[ $key ] ) ) {
				$robots['noindex'] = true;
				unset( $robots['index'] );
			}
		}

		// Rich-result hints that help both search engines and AI crawlers.
		// The values must be strings: wp_robots() only renders `directive:value`
		// for strings and collapses anything else to a bare directive, which
		// Google then ignores.
		if ( empty( $robots['noindex'] ) ) {
			$robots['max-snippet']       = (string) (int) $settings['max_snippet'];
			$robots['max-image-preview'] = (string) $settings['max_image_preview'];
			if ( isset( $settings['max_video_preview'] ) && '' !== (string) $settings['max_video_preview'] ) {
				$robots['max-video-preview'] = (string) (int) $settings['max_video_preview'];
			}

			// A per-post override always wins over the global default.
			if ( is_singular() ) {
				$post = get_queried_object();
				if ( $post instanceof \WP_Post ) {
					$previews = \AiRankSuite\Support\PostSeo::previews( $post->ID );
					if ( isset( $previews['max_snippet'] ) ) {
						$robots['max-snippet'] = (string) (int) $previews['max_snippet'];
					}
					if ( isset( $previews['max_image_preview'] ) ) {
						$robots['max-image-preview'] = $previews['max_image_preview'];
					}
					if ( isset( $previews['max_video_preview'] ) ) {
						$robots['max-video-preview'] = (string) (int) $previews['max_video_preview'];
					}
				}
			}
		}

		return $robots;
	}

	/**
	 * Attachment pages are thin duplicates — send visitors to the real content.
	 */
	public function attachment_redirect(): void {
		if ( ! is_attachment() || empty( $this->settings()['attachment_parent'] ) ) {
			return;
		}
		$post   = get_queried_object();
		$parent = $post instanceof \WP_Post ? (int) $post->post_parent : 0;
		$target = $parent > 0 && 'publish' === get_post_status( $parent )
			? (string) get_permalink( $parent )
			: (string) wp_get_attachment_url( $post->ID ?? 0 );
		if ( '' !== $target ) {
			wp_safe_redirect( $target, 301 );
			exit;
		}
	}

	/**
	 * Append fully custom robots.txt lines (after the AI crawler block).
	 */
	public function robots_txt( string $output ): string {
		$settings = $this->settings();
		if ( empty( $settings['robots_txt_enabled'] ) ) {
			return $output;
		}
		$custom = trim( (string) $settings['robots_txt_custom'] );
		if ( '' === $custom ) {
			return $output;
		}
		return $output . "\n# Custom rules (AI Rank Suite)\n" . $custom . "\n";
	}

	public function routes(): void {

		register_rest_route(
			self::NAMESPACE,
			'/settings/robots',
			array(
				array(
					'methods'             => 'GET',
					'callback'            => array( $this, 'get_settings' ),
					'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
				),
				array(
					'methods'             => 'PUT',
					'callback'            => array( $this, 'update_settings' ),
					'permission_callback' => static fn(): bool => current_user_can( 'manage_options' ),
					'args'                => array(
						'noindex_author'     => array( 'type' => 'boolean' ),
						'noindex_date'       => array( 'type' => 'boolean' ),
						'noindex_search'     => array( 'type' => 'boolean' ),
						'noindex_paginated'  => array( 'type' => 'boolean' ),
						'noindex_attachment' => array( 'type' => 'boolean' ),
						'noindex_password'   => array( 'type' => 'boolean' ),
						'attachment_parent'  => array( 'type' => 'boolean' ),
						'max_snippet'        => array( 'type' => 'integer' ),
						'max_image_preview'  => array(
							'type' => 'string',
							'enum' => array( 'none', 'standard', 'large' ),
						),
						'max_video_preview'  => array( 'type' => 'integer' ),
						'robots_txt_enabled' => array( 'type' => 'boolean' ),
						'robots_txt_custom'  => array(
							'type'              => 'string',
							'sanitize_callback' => 'sanitize_textarea_field',
						),
					),
				),
			)
		);
	}

	public function get_settings(): WP_REST_Response {
		$physical = file_exists( trailingslashit( ABSPATH ) . 'robots.txt' );
		return new WP_REST_Response(
			array(
				'settings'            => $this->settings(),
				'robots_url'          => home_url( '/robots.txt' ),
				'physical_robots_txt' => $physical,
				'directives'          => self::DIRECTIVES,
			)
		);
	}

	public function update_settings( WP_REST_Request $request ): WP_REST_Response {
		$defaults = self::defaults();
		$values   = array();
		foreach ( array_keys( $defaults ) as $key ) {
			if ( $request->has_param( $key ) ) {
				$values[ $key ] = $request->get_param( $key );
			}
		}
		\AiRankSuite\Kernel::service( Options::class )->set( 'robots', $values, $defaults );
		return $this->get_settings();
	}

	/** @return array<string, mixed> */
	private function settings(): array {
		return \AiRankSuite\Kernel::service( Options::class )->get( 'robots', self::defaults() );
	}
}