<?php
/**
 * The same link in another language: the home -> that language's home, a page
 * or post -> its published translation. Anything else (other sites, files,
 * wp-admin, archives, posts without a translation) comes back unchanged.
 */

declare( strict_types = 1 );

namespace AddBlack\Lang\Routing;

defined( 'ABSPATH' ) || exit;

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

final class UrlLocalizer {

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

	public function localize( string $url, string $lang ): string {
		if ( '' === $url || ! $this->urls->pretty() || ! $this->settings->get()->is_language( $lang ) || preg_match( '#^(\#|mailto:|tel:|javascript:|data:)#i', $url ) ) {
			return $url;
		}
		$home  = $this->urls->raw_home();
		$parts = wp_parse_url( $url );
		if ( false === $parts ) {
			return $url;
		}
		if ( isset( $parts['host'] ) && strtolower( $parts['host'] ) !== strtolower( (string) wp_parse_url( $home, PHP_URL_HOST ) ) ) {
			return $url; // Another site.
		}
		$path     = $parts['path'] ?? '';
		$suffix   = ( isset( $parts['query'] ) ? '?' . $parts['query'] : '' ) . ( isset( $parts['fragment'] ) ? '#' . $parts['fragment'] : '' );
		$home_dir = '/' . trim( (string) wp_parse_url( $home, PHP_URL_PATH ), '/' );
		$rel      = '/' . ltrim( '/' === $home_dir ? $path : ( str_starts_with( $path, $home_dir ) ? substr( $path, strlen( $home_dir ) ) : $path ), '/' );

		if ( preg_match( '#^/(wp-admin|wp-json|wp-content|wp-includes|wp-login\.php|feed)(/|$)#', $rel ) || preg_match( '#\.[a-z0-9]{2,5}$#i', $rel ) ) {
			return $url;
		}
		$first = explode( '/', trim( $rel, '/' ) )[0];
		if ( '' !== $first && $this->urls->lang_by_slug( $first ) ) {
			return $url; // Already has a language prefix.
		}
		if ( '/' === $rel ) {
			return $this->urls->lang_home( $lang ) . ltrim( $suffix, '/' );
		}
		$post_id = (int) $this->raw->run( static fn() => url_to_postid( $home . $rel ) );
		if ( ! $post_id ) {
			return $url;
		}
		$target = $this->posts->published_in( $post_id, $lang );
		return $target ? (string) get_permalink( $target ) . $suffix : $url;
	}
}