<?php
/*
 * Copyright (c) 2020. The Nextcloud Bookmarks contributors.
 *
 * This file is licensed under the Affero General Public License version 3 or later. See the COPYING file.
 */

namespace OCA\Bookmarks\Service\Previewers;

use Exception;
use OCA\Bookmarks\Contract\IBookmarkPreviewer;
use OCA\Bookmarks\Contract\IImage;
use OCA\Bookmarks\Db\Bookmark;
use OCA\Bookmarks\Image;
use OCA\Bookmarks\Service\LinkExplorer;
use OCP\Http\Client\IClient;
use OCP\Http\Client\IClientService;
use Psr\Log\LoggerInterface;

class DefaultBookmarkPreviewer implements IBookmarkPreviewer {
	public const CACHE_PREFIX = 'bookmarks.DefaultPreviewService';
	public const HTTP_TIMEOUT = 10 * 1000;

	/** @var IClient */
	protected $client;

	/** @var LinkExplorer */
	protected $linkExplorer;

	/** @var LoggerInterface */
	private $logger;

	/**
	 * @param LinkExplorer $linkExplorer
	 * @param IClientService $clientService
	 * @param LoggerInterface $logger
	 */
	public function __construct(LinkExplorer $linkExplorer, IClientService $clientService, LoggerInterface $logger) {
		$this->linkExplorer = $linkExplorer;
		$this->client = $clientService->newClient();
		$this->logger = $logger;
	}

	/**
	 * @param Bookmark $bookmark
	 *
	 * @return Image|null
	 */
	public function getImage($bookmark): ?IImage {
		if (!isset($bookmark)) {
			return null;
		}
		$site = $this->scrapeUrl($bookmark->getUrl());
		$this->logger->debug('getImage for URL: ' . $bookmark->getUrl() . ' ' . var_export($site, true), ['app' => 'bookmarks']);
		if (isset($site['image']['small'])) {
			return $this->fetchImage($site['image']['small']);
		}
		if (isset($site['image']['large'])) {
			return $this->fetchImage($site['image']['large']);
		}
		return null;
	}

	public function scrapeUrl($url): array {
		return $this->linkExplorer->get($url);
	}

	/**
	 * @param $url
	 * @return Image|null
	 */
	protected function fetchImage($url): ?Image {
		try {
			$response = $this->client->get($url, ['timeout' => self::HTTP_TIMEOUT]);
		} catch (Exception $e) {
			$this->logger->debug($e->getMessage(), ['app' => 'bookmarks']);
			return null;
		}
		$body = $response->getBody();
		$contentType = $response->getHeader('Content-Type');

		// Some HTPP Error occured :/
		if (200 !== $response->getStatusCode()) {
			return null;
		}

		// It's not actually an image, doh.
		if (!isset($contentType) || stripos($contentType, 'image') !== 0) {
			return null;
		}

		return new Image($contentType, $body);
	}
}
