<?php
/**
 * Permalinks with the language prefix: /uk/pro-nas/. The front page and its
 * translations link to their language home (/, /uk/) without a slug.
 */

declare( strict_types = 1 );

namespace AddBlack\Lang\Routing;

defined( 'ABSPATH' ) || exit;

use AddBlack\Lang\Hookable;
use AddBlack\Lang\Hooks;
use AddBlack\Lang\Settings\SettingsRepository;
use AddBlack\Lang\Translation\PostTranslations;

final class Permalinks implements Hookable {

	public function __construct(
		private readonly Urls $urls,
		private readonly SettingsRepository $settings,
		private readonly PostTranslations $posts
	) {}

	public function register(): void {
		Hooks::filter( 'page_link', array( $this, 'page_link' ), 20, 2 );
		Hooks::filter( 'post_link', array( $this, 'post_link' ), 20, 2 );
		Hooks::filter( 'post_type_link', array( $this, 'post_link' ), 20, 2 );
	}

	/** Filters may hand us anything; non-strings pass through untouched. */
	public function page_link( mixed $link, mixed $post_id ): mixed {
		if ( ! is_string( $link ) || ! $this->urls->pretty() || ! $this->settings->get()->is_translatable_type( 'page' ) ) {
			return $link;
		}
		$post_id = (int) $post_id;
		$lang    = $this->posts->language_of( $post_id );
		if ( $this->is_front_group( $post_id ) && 'publish' === get_post_status( $post_id ) ) {
			return $this->urls->lang_home( $lang );
		}
		return $this->urls->add_prefix( $link, $lang );
	}

	public function post_link( mixed $link, mixed $post ): mixed {
		$post = get_post( $post );
		if ( ! is_string( $link ) || ! $post || ! $this->urls->pretty() || ! $this->settings->get()->is_translatable_type( $post->post_type ) ) {
			return $link;
		}
		return $this->urls->add_prefix( $link, $this->posts->language_of( $post->ID ) );
	}

	/** Is the page the static front page in any language? */
	public function is_front_group( int $post_id ): bool {
		if ( 'page' !== get_option( 'show_on_front' ) ) {
			return false;
		}
		$front = $this->urls->raw_option( 'page_on_front' );
		return $front && in_array( $post_id, $this->posts->group( $front ), true );
	}
}