<?php

declare( strict_types=1 );

namespace AcezSeo\Meta;

use AcezSeo\Location\LocationRuleEvaluator;
use AcezSeo\Support\CurrentBlogIndex;

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

/**
 * Resolves the SEO values of the blog index (see CurrentBlogIndex) — shared
 * by BlogIndexMetaTagsProvider and BlogIndexSchemaOutput so the meta tags and
 * the JSON-LD graph never disagree.
 *
 * On a separate "Posts page" every value comes from that page through
 * MetaResolver (meta box fields, then the page post type's templates), so the
 * fields the user filled in the editor take effect. A "latest posts" front
 * page has no post: the description falls back to the site tagline and the
 * title stays the one WordPress builds ("Site name – Tagline").
 */
final class BlogIndexResolver
{
	private MetaResolver $resolver;
	private LocationRuleEvaluator $location_evaluator;

	public function __construct( MetaResolver $resolver, LocationRuleEvaluator $location_evaluator )
	{
		$this->resolver           = $resolver;
		$this->location_evaluator = $location_evaluator;
	}

	/**
	 * Whether the plugin outputs anything for the current request: a blog
	 * index that is either the front page, or a supported "Posts page"
	 * matched by the location rules of its post type.
	 */
	public function applies(): bool
	{
		if ( ! CurrentBlogIndex::is_active() )
		{
			return false;
		}

		if ( is_front_page() )
		{
			return true;
		}

		$page = CurrentBlogIndex::posts_page();

		return null !== $page && $this->location_evaluator->applies( $page );
	}

	/**
	 * applies(), plus — on a "Posts page" — the page post type's schema
	 * toggle, the same gate SchemaOutput uses for singular pages.
	 */
	public function applies_to_schema(): bool
	{
		if ( ! $this->applies() )
		{
			return false;
		}

		$page = $this->posts_page();

		return null === $page || $this->location_evaluator->applies_to_schema( $page );
	}

	public function posts_page(): ?\WP_Post
	{
		return CurrentBlogIndex::posts_page();
	}

	/**
	 * Full document title, or '' to keep the one WordPress builds. Listing
	 * pages 2+ get a page suffix, otherwise they would all share one title.
	 */
	public function title(): string
	{
		$page = $this->posts_page();

		if ( null === $page )
		{
			return '';
		}

		$title = $this->resolver->title( $page );

		if ( '' === $title || CurrentBlogIndex::page_number() < 2 )
		{
			return $title;
		}

		/* translators: %d: page number of a paginated post listing. */
		return $title . ' - ' . sprintf( __( 'Page %d', 'acez-seo' ), CurrentBlogIndex::page_number() );
	}

	/**
	 * Name of the listing itself — the page title, or the site name on a
	 * "latest posts" front page (og:title fallback, CollectionPage name).
	 */
	public function name(): string
	{
		$page = $this->posts_page();

		return null !== $page ? get_the_title( $page ) : (string) get_bloginfo( 'name' );
	}

	public function description(): string
	{
		$page        = $this->posts_page();
		$description = null !== $page ? $this->resolver->description( $page ) : '';

		return '' !== $description ? $description : wp_strip_all_tags( (string) get_bloginfo( 'description' ) );
	}

	/**
	 * Raw (unescaped) canonical URL. Page 1 of a "Posts page" honours the
	 * custom canonical from its meta box; listing pages 2+ are canonical to
	 * themselves (Google's guidance for paginated series).
	 */
	public function canonical(): string
	{
		$page = $this->posts_page();

		if ( null !== $page && CurrentBlogIndex::page_number() < 2 )
		{
			return $this->resolver->canonical( $page );
		}

		return CurrentBlogIndex::url();
	}

	/**
	 * @return array{index: bool, follow: bool}|null Null on a "latest posts" front page.
	 */
	public function robots(): ?array
	{
		$page = $this->posts_page();

		return null !== $page ? $this->resolver->robots( $page ) : null;
	}

	public function og_image_url(): string
	{
		$page = $this->posts_page();

		return null !== $page ? $this->resolver->og_image_url( $page ) : '';
	}

	public function twitter_card(): string
	{
		$page = $this->posts_page();
		$card = null !== $page ? $this->resolver->twitter_card( $page ) : '';

		if ( '' !== $card )
		{
			return $card;
		}

		return '' !== $this->og_image_url() ? 'summary_large_image' : 'summary';
	}
}