<?php

declare(strict_types=1);

namespace LinkCheckup\Features\LinkLists;

use LinkCheckup\Shared\Links\ClosestPageFinder;
use LinkCheckup\Shared\Links\Link;
use LinkCheckup\Shared\Links\Verdict;

final class SuggestionFinder {

	public function __construct(
		private ClosestPageFinder $closest_page_finder,
		private SiteHomeProbe $site_home_probe,
		private ArchiveAddress $archive_address
	) {
	}

	/** @return list<array{kind: string, url: string}> */
	public function suggestions_for( Link $link ): array {
		if ( Verdict::Broken !== $link->verdict ) {
			return array();
		}

		if ( $link->internal ) {
			return $this->internal_suggestions( $link );
		}

		return $this->external_suggestions( $link );
	}

	/** @return list<array{kind: string, url: string}> */
	private function internal_suggestions( Link $link ): array {
		$closest_page = $this->closest_page_finder->closest_to( $link->url );

		if ( null === $closest_page ) {
			return array();
		}

		return array(
			$this->suggestion( SuggestionKind::ClosestPage, $closest_page ),
		);
	}

	/** @return list<array{kind: string, url: string}> */
	private function external_suggestions( Link $link ): array {
		$suggestions = array();
		$site_home   = $this->site_home_probe->answering_home_of( $link->url );

		if ( null !== $site_home ) {
			$suggestions[] = $this->suggestion(
				SuggestionKind::SiteHome,
				$site_home
			);
		}

		$archived_copy = $this->archive_address->archived_copy_of( $link );

		if ( null !== $archived_copy ) {
			$suggestions[] = $this->suggestion(
				SuggestionKind::Archive,
				$archived_copy
			);
		}

		return $suggestions;
	}

	/** @return array{kind: string, url: string} */
	private function suggestion( SuggestionKind $kind, string $url ): array {
		return array(
			'kind' => $kind->value,
			'url'  => $url,
		);
	}
}