<?php
/**
 * Show in preview: the post preview outlines one failing element with its number. Only a logged-in user who may edit
 * the post and see results, with a valid nonce for that post, gets the highlight script; everyone else gets the
 * normal page and nothing from Waysill.
 *
 * @package Waysill
 */

defined( 'ABSPATH' ) || exit;

/**
 * The issue to highlight on the current front-end request, or null.
 *
 * @return array{selector: string, number: int, title: string}|null
 */
function waysill_highlight_target(): ?array {
	if ( ! isset( $_GET['waysill_highlight'], $_GET['waysill_nonce'] ) || ! is_user_logged_in() || ! is_singular() ) {
		return null;
	}
	$post_id = (int) get_queried_object_id();
	if ( ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_GET['waysill_nonce'] ) ), 'waysill_highlight_' . $post_id )
		|| ! current_user_can( 'edit_post', $post_id ) || ! waysill_user_can_see_results() ) {
		return null;
	}
	$key    = sanitize_key( wp_unslash( $_GET['waysill_highlight'] ) );
	$result = waysill_get_result( $post_id );
	foreach ( $result['issues'] ?? array() as $index => $issue ) {
		if ( is_array( $issue ) && ( $issue['key'] ?? '' ) === $key ) {
			return array(
				'selector' => (string) $issue['selector'],
				'number'   => $index + 1,
				'title'    => (string) ( $issue['text']['title'] ?? '' ),
			);
		}
	}
	return null;
}

/** Enqueues the highlight script when the request asks for it and is allowed to. */
function waysill_enqueue_highlight(): void {
	$target = waysill_highlight_target();
	if ( null !== $target ) {
		waysill_enqueue_entry( 'highlight', array( 'highlight' => $target ) );
	}
}
add_action( 'wp_enqueue_scripts', 'waysill_enqueue_highlight' );