<?php
/**
 * Finds posts and pages by title for the excluded-pages picker.
 *
 * @package AdPix\Analytics
 */

declare( strict_types = 1 );

namespace AdPix\Analytics\Service;

defined( 'ABSPATH' ) || exit;

/**
 * Turns a title search into a short list of content the tag could be shown on, and stored IDs back
 * into names a person recognises.
 *
 * Only public post types are offered: the tag is never printed on anything else, so excluding it
 * would do nothing while still looking like a setting that had been made.
 */
final class PageFinder {

	/**
	 * Most results one search returns. Enough to scan, few enough that the list stays a list.
	 */
	private const LIMIT = 20;

	/**
	 * Statuses worth offering: what is live now, what is about to be, and what only logged-in users see.
	 *
	 * @var string[]
	 */
	private const STATUSES = array( 'publish', 'future', 'private' );

	/**
	 * Content whose title matches the search. A search that is a number also matches that ID, so
	 * someone who knows the ID from the editor's URL can still type it.
	 *
	 * @param string $search What was typed.
	 * @return array<int,array{id:int,title:string,type:string}>
	 */
	public function search( string $search ): array {
		$search = trim( $search );

		if ( '' === $search ) {
			return array();
		}

		$ids = get_posts(
			array(
				'post_type'              => $this->post_types(),
				'post_status'            => self::STATUSES,
				's'                      => $search,
				'search_columns'         => array( 'post_title' ),
				'posts_per_page'         => self::LIMIT,
				'orderby'                => 'relevance',
				'fields'                 => 'ids',
				'no_found_rows'          => true,
				'suppress_filters'       => false,
				'update_post_meta_cache' => false,
				'update_post_term_cache' => false,
			)
		);

		if ( ctype_digit( $search ) ) {
			array_unshift( $ids, (int) $search );
		}

		return $this->describe( $ids );
	}

	/**
	 * Name each ID, in the order given, dropping any that no longer point at offerable content.
	 *
	 * @param int[] $ids Post IDs.
	 * @return array<int,array{id:int,title:string,type:string}>
	 */
	public function describe( array $ids ): array {
		$types  = $this->post_types();
		$result = array();

		foreach ( array_unique( array_map( 'absint', $ids ) ) as $id ) {
			$post = $id > 0 ? get_post( $id ) : null;

			if ( ! $post || ! in_array( $post->post_type, $types, true ) ) {
				continue;
			}

			$type  = get_post_type_object( $post->post_type );
			$title = trim( wp_strip_all_tags( get_the_title( $post ) ) );

			$result[] = array(
				'id'    => (int) $post->ID,
				/* translators: %d: post ID. */
				'title' => '' !== $title ? $title : sprintf( __( '(no title) #%d', 'adpix-analytics' ), $post->ID ),
				'type'  => $type ? (string) $type->labels->singular_name : $post->post_type,
			);
		}

		return $result;
	}

	/**
	 * Post types a visitor can land on.
	 *
	 * @return string[]
	 */
	private function post_types(): array {
		$types = get_post_types( array( 'public' => true ) );

		// Attachments are public but have no page of their own on most sites worth measuring.
		unset( $types['attachment'] );

		return array_values( $types );
	}
}