<?php

declare( strict_types=1 );

namespace AcezSeo\Support;

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

/**
 * Describes the blog index request — the posts listing WordPress serves when
 * is_home() is true. It comes in two shapes:
 *
 * - "Your homepage displays: Your latest posts" — the index IS the front
 *   page and has no WP_Post behind it;
 * - a static front page plus a separate "Posts page" (`page_for_posts`) —
 *   the index lives at that page's URL and the page carries the SEO fields
 *   the user filled in the editor.
 *
 * Neither shape is singular, so CurrentSingularPost (and everything built on
 * it) never sees these requests — this class is their counterpart, the way
 * CurrentArchiveTerm is for taxonomy archives.
 */
final class CurrentBlogIndex
{
	public static function is_active(): bool
	{
		return is_home();
	}

	/**
	 * The page assigned as "Posts page", when the index is served from one —
	 * null on a "latest posts" front page, or when that page's post type is
	 * not handled by the plugin.
	 */
	public static function posts_page(): ?\WP_Post
	{
		if ( ! self::is_active() || is_front_page() )
		{
			return null;
		}

		$page = get_post( (int) get_option( 'page_for_posts' ) );

		if ( ! ( $page instanceof \WP_Post ) || ! in_array( $page->post_type, PostTypes::supported(), true ) )
		{
			return null;
		}

		return $page;
	}

	public static function page_number(): int
	{
		return max( 1, (int) get_query_var( 'paged' ) );
	}

	/**
	 * Raw (unescaped) URL of the current listing page — escape on output.
	 */
	public static function url(): string
	{
		if ( self::page_number() > 1 )
		{
			return get_pagenum_link( self::page_number(), false );
		}

		$page = self::posts_page();

		if ( null !== $page )
		{
			$permalink = get_permalink( $page );

			return is_string( $permalink ) ? $permalink : '';
		}

		return home_url( '/' );
	}
}