<?php
/**
 * Keeps imported focus keywords current as posts are saved and deleted.
 *
 * @package Postlinkly
 * @since   1.18.1
 */

declare(strict_types=1);

namespace Postlinkly\Keywords;

use Postlinkly\Hooks\ServiceProvider;
use Postlinkly\Post\PostModel;
use WP_Post;

/**
 * Re-imports a post's focus keywords from the active SEO plugin each time the
 * post is saved, and removes them when the post is deleted.
 *
 * The indexing job's {@see \Postlinkly\Indexing\Stage\TargetKeywordsStage}
 * imports every existing post once; this keeps the stored copy in step
 * afterwards, so a keyword changed in the SEO plugin affects suggestions on
 * the next save rather than the next full reindex.
 *
 * @since 1.18.1
 */
final class TargetKeywordSyncer implements ServiceProvider {

	/**
	 * @var TargetKeywordManager
	 */
	private TargetKeywordManager $manager;

	/**
	 * @var array<int, string>
	 */
	private array $post_types;

	/**
	 * @var array<int, string>
	 */
	private array $post_statuses;

	/**
	 * @since 1.18.1
	 *
	 * @param TargetKeywordManager $manager       Imports and stores keywords.
	 * @param array<int, string>   $post_types    Post types that can be link targets.
	 * @param array<int, string>   $post_statuses Post statuses that can be link targets.
	 */
	public function __construct( TargetKeywordManager $manager, array $post_types, array $post_statuses ) {
		$this->manager       = $manager;
		$this->post_types    = array() !== $post_types ? $post_types : array( 'post' );
		$this->post_statuses = array() !== $post_statuses ? $post_statuses : array( 'publish' );
	}

	/**
	 * @since 1.18.1
	 *
	 * @return array<int, array<int, mixed>>
	 */
	public function get_hooks(): array {
		return array(
			// Not save_post: SEO plugins store their fields during or after
			// save_post, and when saving from the block editor those fields
			// arrive in the REST request only after the post itself is
			// written. wp_after_insert_post fires once both are saved.
			array( 'wp_after_insert_post', array( $this, 'on_post_saved' ), 20, 2 ),
			// Permanent deletion; trashing is a status change handled above.
			array( 'delete_post', array( $this, 'on_post_deleted' ), 10, 1 ),
		);
	}

	/**
	 * Imports the saved post's focus keywords, or removes them if the post can
	 * no longer be a link target.
	 *
	 * A draft, a trashed post, a revision, or a post type that isn't scanned is
	 * never offered as a link target, so its keywords are removed rather than
	 * kept around to go stale.
	 *
	 * @since 1.18.1
	 * @hook  wp_after_insert_post
	 *
	 * @param int   $post_id Post id.
	 * @param mixed $post    Post object.
	 *
	 * @return void
	 */
	public function on_post_saved( int $post_id, $post ): void {
		if ( ! $post instanceof WP_Post ) {
			return;
		}

		$is_link_target = in_array( $post->post_type, $this->post_types, true )
			&& in_array( $post->post_status, $this->post_statuses, true );

		if ( $is_link_target ) {
			$this->manager->sync( $post_id, PostModel::TYPE_POST );
			return;
		}

		$this->manager->forget( $post_id, PostModel::TYPE_POST );
	}

	/**
	 * Removes a permanently deleted post's keywords.
	 *
	 * @since 1.18.1
	 * @hook  delete_post
	 *
	 * @param int $post_id Post id.
	 *
	 * @return void
	 */
	public function on_post_deleted( int $post_id ): void {
		$this->manager->forget( $post_id, PostModel::TYPE_POST );
	}
}