<?php
/**
 * The current page in every language it is published in (for hreflang and
 * the language switcher): lang => URL.
 */

declare( strict_types = 1 );

namespace AddBlack\Lang\Routing;

defined( 'ABSPATH' ) || exit;

use AddBlack\Lang\Settings\SettingsRepository;
use AddBlack\Lang\Terms\TermTranslations;
use AddBlack\Lang\Translation\PostTranslations;
use WP_Post;
use WP_Term;

final class Alternates {

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

	/** @return array<string, string> lang => URL, published versions only. */
	public function current_page(): array {
		$out = array();
		if ( is_front_page() && 'page' === get_option( 'show_on_front' ) ) {
			foreach ( $this->posts->group( $this->urls->raw_option( 'page_on_front' ) ) as $lang => $id ) {
				if ( 'publish' === get_post_status( $id ) ) {
					$out[ $lang ] = $this->urls->lang_home( $lang );
				}
			}
			return $out;
		}
		if ( is_search() ) {
			// Same search in every language: /?s=x, /uk/?s=x.
			foreach ( array_keys( $this->settings->get()->languages() ) as $lang ) {
				$out[ (string) $lang ] = add_query_arg( 's', rawurlencode( get_search_query( false ) ), $this->urls->lang_home( (string) $lang ) );
			}
			return $out;
		}
		if ( is_home() && is_front_page() ) {
			// Latest posts on the front page: every language home is the same page.
			foreach ( array_keys( $this->settings->get()->languages() ) as $lang ) {
				$out[ (string) $lang ] = $this->urls->lang_home( (string) $lang );
			}
			return $out;
		}
		if ( is_category() || is_tag() || is_tax() ) {
			$term = get_queried_object();
			if ( $term instanceof WP_Term && $this->terms->is_translatable( $term->taxonomy ) ) {
				foreach ( $this->terms->group( $term->term_id ) as $lang => $id ) {
					$link = get_term_link( $id );
					if ( is_string( $link ) ) {
						$out[ $lang ] = $link;
					}
				}
			}
			return $out;
		}
		if ( is_singular() ) {
			$post = get_queried_object();
			if ( $post instanceof WP_Post && $this->settings->get()->is_translatable_type( $post->post_type ) ) {
				foreach ( $this->posts->group( $post->ID ) as $lang => $id ) {
					if ( 'publish' === get_post_status( $id ) ) {
						$out[ $lang ] = (string) get_permalink( $id );
					}
				}
			}
		}
		return $out;
	}
}