<?php
/**
 * What depends on a post: links, menus, redirects, children, sitemap.
 *
 * @package OrbitstemSEO
 */

namespace Orbitstem\SEO\Guardian;

use Orbitstem\SEO\Core\Settings;
use Orbitstem\SEO\Diagnostics\Tables;
use Orbitstem\SEO\Frontend\Resolver;
use Orbitstem\SEO\Links\Url;
use WP_Post;

defined( 'ABSPATH' ) || exit;

/**
 * Known dependencies only: links in post content (from the link index, as
 * of the last save or scan), navigation menu items, Orbitstem redirects and
 * child pages. Links in widgets, page-builder data, other sites, bookmarks
 * and search results cannot be seen here; the result says so.
 */
class Impact {

	/**
	 * Settings service.
	 *
	 * @var Settings
	 */
	private $settings;

	/**
	 * SEO value resolver.
	 *
	 * @var Resolver
	 */
	private $resolver;

	/**
	 * Constructor.
	 *
	 * @param Settings $settings Settings.
	 * @param Resolver $resolver Resolver.
	 */
	public function __construct( Settings $settings, Resolver $resolver ) {
		$this->settings = $settings;
		$this->resolver = $resolver;
	}

	/**
	 * Dependencies of one post.
	 *
	 * @param WP_Post $post Post.
	 * @return array
	 */
	public function for_post( WP_Post $post ) {
		global $wpdb;
		$url                  = Url::normalize( (string) get_permalink( $post ), home_url( '/' ) );
		$indexing             = $this->resolver->indexing_for_post( $post );
		$result               = array(
			'post_id'             => $post->ID,
			'title'               => get_the_title( $post ),
			'url'                 => $url,
			'published'           => 'publish' === $post->post_status,
			'inbound'             => 0,
			'sources'             => array(),
			'menus'               => array(),
			'menu_items'          => 0,
			'redirects_to'        => 0,
			'children'            => 0,
			'noindex'             => $indexing ? (bool) $indexing['noindex'] : false,
			'canonical_elsewhere' => $indexing ? Url::normalize( $indexing['canonical'], home_url( '/' ) ) !== $url : false,
			'in_sitemap'          => false,
			'limits'              => __( 'Links in widgets, page-builder layouts, other websites and bookmarks are not included.', 'orbitstem-seo' ),
		);
		$result['in_sitemap'] = $result['published'] && ! $result['noindex'] && ! $result['canonical_elsewhere'] && '' === $post->post_password
			&& $this->settings->get( 'sitemap_enabled' ) && $this->settings->post_type( $post->post_type, 'sitemap' )
			&& ! ( new \Orbitstem\SEO\Content\MetaRepository() )->get_post( $post->ID, 'sitemap_exclude' );

		if ( Tables::exist_cached() ) {
			// phpcs:disable WordPress.DB.DirectDatabaseQuery
			$sources = $wpdb->get_results(
				$wpdb->prepare(
					"SELECT DISTINCT l.source_id, p.post_title FROM %i l INNER JOIN %i p ON p.ID = l.source_id WHERE l.target_id = %d AND l.kind = 'link' AND l.source_id <> %d ORDER BY l.source_id DESC",
					Tables::links(),
					$wpdb->posts,
					$post->ID,
					$post->ID
				),
				ARRAY_A
			);
			// phpcs:enable
			$result['inbound'] = count( $sources );
			foreach ( array_slice( $sources, 0, 10 ) as $s ) {
				$result['sources'][] = array(
					'id'    => (int) $s['source_id'],
					'title' => $s['post_title'],
				);
			}
		}

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- menu items reference posts through meta; no core lookup by target.
		$items = array_map( 'intval', $wpdb->get_col( $wpdb->prepare( "SELECT m.post_id FROM {$wpdb->postmeta} m INNER JOIN {$wpdb->postmeta} t ON t.post_id = m.post_id AND t.meta_key = '_menu_item_type' AND t.meta_value = 'post_type' WHERE m.meta_key = '_menu_item_object_id' AND m.meta_value = %s", (string) $post->ID ) ) );
		if ( $items ) {
			$result['menu_items'] = count( $items );
			$menus                = wp_get_object_terms( $items, 'nav_menu', array( 'fields' => 'names' ) );
			$result['menus']      = is_array( $menus ) ? array_values( array_unique( $menus ) ) : array();
		}

		if ( Tables::v3_ready() ) {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery
			$result['redirects_to'] = (int) $wpdb->get_var( $wpdb->prepare( 'SELECT COUNT(*) FROM %i WHERE target IN (%s, %s)', Tables::redirects(), $url, untrailingslashit( $url ) ) );
		}

		if ( is_post_type_hierarchical( $post->post_type ) ) {
			$result['children'] = count(
				get_children(
					array(
						'post_parent' => $post->ID,
						'post_type'   => $post->post_type,
						'post_status' => 'publish',
						'fields'      => 'ids',
					)
				)
			);
		}
		return $result;
	}

	/**
	 * Plain-language consequences of removing a post, one per line.
	 *
	 * @param array $impact Result of for_post().
	 * @return string[]
	 */
	public static function removal_consequences( array $impact ) {
		$lines = array();
		if ( $impact['inbound'] ) {
			/* translators: %d: number of posts */
			$lines[] = sprintf( _n( '%d post links to this page; those links will lead to a "page not found" unless you add a redirect.', '%d posts link to this page; those links will lead to a "page not found" unless you add a redirect.', $impact['inbound'], 'orbitstem-seo' ), $impact['inbound'] );
		}
		if ( $impact['menu_items'] ) {
			/* translators: %s: menu names */
			$lines[] = sprintf( __( 'It appears in navigation menus (%s); WordPress removes those menu items.', 'orbitstem-seo' ), implode( ', ', $impact['menus'] ) );
		}
		if ( $impact['redirects_to'] ) {
			/* translators: %d: number of redirects */
			$lines[] = sprintf( _n( '%d redirect points here and will then lead to a missing page.', '%d redirects point here and will then lead to a missing page.', $impact['redirects_to'], 'orbitstem-seo' ), $impact['redirects_to'] );
		}
		if ( $impact['children'] ) {
			/* translators: %d: number of child pages */
			$lines[] = sprintf( _n( '%d child page sits under it. Its address contains this page\'s slug, which WordPress renames in the trash, so links to the child page break too.', '%d child pages sit under it. Their addresses contain this page\'s slug, which WordPress renames in the trash, so links to them break too.', $impact['children'], 'orbitstem-seo' ), $impact['children'] );
		}
		if ( $impact['in_sitemap'] ) {
			$lines[] = __( 'It leaves the sitemap; search engines will drop it from results over the next weeks.', 'orbitstem-seo' );
		}
		return $lines;
	}
}