<?php
declare(strict_types=1);

namespace App\Service;

use Psr\Log\LoggerInterface;
use Symfony\Component\DependencyInjection\Attribute\Autowire;
use Symfony\Component\DependencyInjection\Attribute\Target;
use Symfony\Contracts\HttpClient\Exception\ExceptionInterface;
use Symfony\Contracts\HttpClient\HttpClientInterface;

/**
 * Downloads covers from LibraryThing (https://www.librarything.com/services/covers.php).
 */
class LibraryThingCovers {
	private const int MAX_BYTES = 10 * 1024 * 1024;

	public function __construct(
		#[Target('librarything.client')]
		private readonly HttpClientInterface $libraryThingClient,
		private readonly LoggerInterface     $logger,
		#[Autowire('%app.librarything_api_key%')]
		private readonly ?string             $apiKey,
	) {
	}

	public function isEnabled(): bool {
		return trim((string)$this->apiKey) !== '';
	}

	/**
	 * @return string|null the image data, or null when there is no cover or it could not be fetched
	 */
	public function download(string $isbn): ?string {
		if (!$this->isEnabled() || preg_match('/^[\dX]{10,13}$/', $isbn) !== 1) {
			return null;
		}

		try {
			$response = $this->libraryThingClient->request(
				'GET',
				\sprintf('/devkey/%s/large/isbn/%s', rawurlencode(trim((string)$this->apiKey)), $isbn),
			);

			if ($response->getStatusCode() !== 200) {
				$this->logger->warning('LibraryThing returned HTTP {status} for ISBN {isbn}.', [
					'status' => $response->getStatusCode(),
					'isbn' => $isbn,
				]);

				return null;
			}

			$data = $response->getContent();
		} catch (ExceptionInterface $exception) {
			// The message would contain the URL, and with it the key.
			$this->logger->warning('The LibraryThing cover for ISBN {isbn} could not be downloaded.', ['isbn' => $isbn]);

			return null;
		}

		if (\strlen($data) > self::MAX_BYTES) {
			return null;
		}

		$size = @getimagesizefromstring($data);

		return $size === false || $size[0] <= 1 || $size[1] <= 1 ? null : $data;
	}
}