<?php
/**
 * @copyright Copyright (c) 2020 Matthias Heinisch <nextcloud@matthiasheinisch.de>
 *
 * @author Matthias Heinisch <nextcloud@matthiasheinisch.de>
 *
 * @license GNU AGPL version 3 or any later version
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *
 */

namespace OCA\Contacts\Service\Social;

use OCP\Http\Client\IClient;
use OCP\Http\Client\IClientService;

class MastodonProvider implements ISocialProvider {
	/** @var IClient */
	private $httpClient;

	/** @var string */
	public $name = 'mastodon';

	public function __construct(IClientService $httpClient) {
		$this->httpClient = $httpClient->newClient();
	}

	/**
	 * Returns if this provider supports this contact
	 *
	 * @param {array} contact info
	 *
	 * @return bool
	 */
	public function supportsContact(array $contact):bool {
		if (!array_key_exists('X-SOCIALPROFILE', $contact)) {
			return false;
		}
		$profiles = $this->getProfileIds($contact);
		return isset($profiles) && count($profiles) > 0;
	}

	/**
	 * Returns all possible profile-picture urls
	 *
	 * @param {array} contact information
	 *
	 * @return array
	 */
	public function getImageUrls(array $contact):array {
		$profileIds = $this->getProfileIds($contact);
		$urls = [];
		foreach ($profileIds as $profileId) {
			$url = $this->getImageUrl($profileId);
			if (isset($url)) {
				$urls[] = $url;
			}
		}
		return $urls;
	}

	/**
	 * Returns the profile-picture url
	 *
	 * @param {array} contact information
	 *
	 * @return string|null
	 */
	public function getImageUrl(string $profileUrl):?string {
		try {
			$result = $this->httpClient->get($profileUrl, ['headers' => ['Accept' => 'application/json']]);
			$jsonResult = json_decode($result->getBody(), true);
			return $jsonResult["icon"]["url"] ?? null;
		} catch (\Exception $e) {
			return null;
		}
	}

	/**
	 * Returns all possible profile URI for contact by searching the mastodon instance
	 *
	 * @param {array} contact information
	 *
	 * @return array of possible profileIds
	 */
	protected function getProfileIds($contact):array {
		$socialprofiles = $contact['X-SOCIALPROFILE'];
		$profileIds = [];
		if (isset($socialprofiles)) {
			foreach ($socialprofiles as $profile) {
				if (strtolower($profile['type']) == $this->name) {
					$masto_user_server = $this->cleanupId($profile['value']);
					if (isset($masto_user_server)) {
						try {
							[$masto_user, $masto_server] = $masto_user_server;
							# search for user webfinger
							$webfinger = $masto_server . '/.well-known/webfinger?resource=acct:' . $masto_user . '@' . parse_url($masto_server)["host"];
							$result = $this->httpClient->get($webfinger);
							$jsonResult = json_decode($result->getBody(), null, 512, JSON_THROW_ON_ERROR);
							# find account link
							foreach ($jsonResult->links as $link) {
								if (($link->rel == "self") and ($link->type == "application/activity+json")) {
									$profileId = $link->href;
									$profileIds[] = $profileId;
									break;
								}
							}
						} catch (\Exception $e) {
							continue;
						}
					}
				}
			}
		}
		return $profileIds;
	}

	/**
	 * Returns the profile-id
	 *
	 * @param {string} the value from the contact's x-socialprofile
	 *
	 * @return array username and server instance
	 */
	protected function cleanupId(string $candidate):?array {
		$candidate = preg_replace('/^' . preg_quote('x-apple:', '/') . '/', '', $candidate);
		try {
			$user_server = explode('@', $candidate);
			if (strpos($candidate, 'http') !== 0) {
				$masto_server = "https://" . array_pop($user_server);
				$masto_user = array_pop($user_server);
			} else {
				$masto_user = array_pop($user_server);
				$masto_server = array_pop($user_server);
			}
			if ((empty($masto_server)) || (empty($masto_user))) {
				return null;
			}
			$masto_user = trim($masto_user, '/');
			$masto_server = trim($masto_server, '/');
			return array($masto_user, $masto_server);
		} catch (\Exception $e) {
			return null;
		}
	}
}