<?php
/**
 * Videos that are gone (F-CONTENT-06).
 *
 * @package ForensixDigital
 */

declare(strict_types=1);

namespace ForensixDigital\Apps\Content;

defined( 'ABSPATH' ) || exit;

use ForensixDigital\Services\Findings\Observation;
use ForensixDigital\Services\Findings\Priority;
use ForensixDigital\Services\Scan\Check;
use ForensixDigital\Services\Scan\ParsedPage;
use ForensixDigital\Services\Scan\Reference;
use ForensixDigital\Services\Scan\TargetResult;

/**
 * An embedded YouTube or Vimeo player still loads when its video was deleted, so the page looks
 * fine to a link checker. The check asks the video site's public oEmbed address instead, which
 * answers "not found" for a deleted video. Only the video address is sent, nothing about visitors.
 * Maps cannot be checked this way and are not tested.
 */
final class EmbedCheck implements Check {

	public const ID = 'content.broken_embed';

	/**
	 * Creates the check.
	 *
	 * @param bool $enabled Whether pages on other sites may be asked (the scan setting).
	 */
	public function __construct( private bool $enabled = true ) {}

	/**
	 * Check id.
	 */
	public function id(): string {
		return self::ID;
	}

	/**
	 * The oEmbed address for the video behind an embed URL, or null for other embeds.
	 *
	 * @param string $url Absolute URL of the frame.
	 */
	public static function oembed_url( string $url ): ?string {
		if ( 1 === preg_match( '~^https?://(?:www\.)?youtube(?:-nocookie)?\.com/embed/([A-Za-z0-9_-]{11})(?:[/?#]|$)~i', $url, $m ) ) {
			return 'https://www.youtube.com/oembed?format=json&url=' . rawurlencode( 'https://www.youtube.com/watch?v=' . $m[1] );
		}
		if ( 1 === preg_match( '~^https?://player\.vimeo\.com/video/(\d{3,})(?:[/?#]|$)~i', $url, $m ) ) {
			return 'https://vimeo.com/api/oembed.json?url=' . rawurlencode( 'https://vimeo.com/' . $m[1] );
		}
		return null;
	}

	/**
	 * The oEmbed addresses this page needs answers for.
	 *
	 * @param ParsedPage $page Parsed page.
	 * @return string[]
	 */
	public function targets( ParsedPage $page ): array {
		if ( ! $this->enabled ) {
			return array();
		}
		$urls = array();
		foreach ( $page->references as $ref ) {
			$oembed = Reference::FRAME === $ref->kind ? self::oembed_url( $ref->url ) : null;
			if ( null !== $oembed ) {
				$urls[ $oembed ] = true;
			}
		}
		return array_keys( $urls );
	}

	/**
	 * Videos that are gone or not available for embedding.
	 *
	 * @param ParsedPage $page    Parsed page.
	 * @param array      $results Results by URL.
	 * @phpstan-param array<string, \ForensixDigital\Services\Scan\TargetResult> $results
	 * @return array<int, array{observation: Observation, context: string}>
	 */
	public function inspect( ParsedPage $page, array $results ): array {
		$hits = array();
		foreach ( $page->references as $ref ) {
			$oembed = Reference::FRAME === $ref->kind ? self::oembed_url( $ref->url ) : null;
			$result = null === $oembed ? null : ( $results[ $oembed ] ?? null );
			if ( null === $result ) {
				continue;
			}
			if ( TargetResult::BROKEN === $result->verdict ) {
				$title = __( 'An embedded video no longer exists', 'forensix-digital' );
				$type  = Priority::ERROR;
			} elseif ( in_array( $result->status, array( 401, 403 ), true ) ) {
				$title = __( 'An embedded video is private or cannot be embedded', 'forensix-digital' );
				$type  = Priority::INCONCLUSIVE;
			} else {
				continue;
			}
			$hits[] = array(
				'observation' => new Observation( self::ID, Priority::MEDIUM, $type, $title, $ref->url, $ref->source->type, $ref->source->ref, '', array( 'http_status' => $result->status ) ),
				'context'     => $ref->url,
			);
		}
		return $hits;
	}
}