<?php
/**
 * @copyright Copyright (C) 2010-2021, the Friendica project
 *
 * @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 <https://www.gnu.org/licenses/>.
 *
 */

namespace Friendica\Module\Diaspora;

use Friendica\BaseModule;
use Friendica\DI;
use Friendica\Model\User;
use Friendica\Network\HTTPException;
use Friendica\Protocol\Diaspora;
use Friendica\Util\Network;
use Psr\Log\LoggerInterface;

/**
 * This module is part of the Diaspora protocol.
 * It is used for receiving single posts either for public or for a specific user.
 */
class Receive extends BaseModule
{
	/** @var LoggerInterface */
	private static $logger;

	public static function init()
	{
		self::$logger = DI::logger();
	}

	public static function post()
	{
		$enabled = DI::config()->get('system', 'diaspora_enabled', false);
		if (!$enabled) {
			self::$logger->info('Diaspora disabled.');
			throw new HTTPException\ForbiddenException(DI::l10n()->t('Access denied.'));
		}

		if (static::$parameters['type'] === 'public') {
			self::receivePublic();
		} else if (static::$parameters['type'] === 'users') {
			self::receiveUser(static::$parameters['guid']);
		}
	}

	/**
	 * Receive a public Diaspora posting
	 *
	 * @throws HTTPException\InternalServerErrorException
	 * @throws \ImagickException
	 */
	private static function receivePublic()
	{
		self::$logger->info('Diaspora: Receiving post.');

		$msg = self::decodePost();

		self::$logger->info('Diaspora: Dispatching.');

		Diaspora::dispatchPublic($msg);
	}

	/**
	 * Receive a Diaspora posting for a user
	 *
	 * @param string $guid The GUID of the importer
	 *
	 * @throws HTTPException\InternalServerErrorException
	 * @throws \ImagickException
	 */
	private static function receiveUser(string $guid)
	{
		self::$logger->info('Diaspora: Receiving post.');

		$importer = User::getByGuid($guid);

		$msg = self::decodePost(false, $importer['prvkey'] ?? '');

		self::$logger->info('Diaspora: Dispatching.');

		if (Diaspora::dispatch($importer, $msg)) {
			throw new HTTPException\OKException();
		} else {
			// We couldn't process the content.
			// To avoid the remote system trying again we send the message that we accepted the content.
			throw new HTTPException\AcceptedException();
		}
	}

	/**
	 * Decodes a Diaspora message based on the posted data
	 *
	 * @param string $privKey The private key of the importer
	 * @param bool   $public  True, if the post is public
	 *
	 * @return array
	 * @throws HTTPException\InternalServerErrorException
	 * @throws \ImagickException
	 */
	private static function decodePost(bool $public = true, string $privKey = '')
	{
		if (empty($_POST['xml'])) {

			$postdata = Network::postdata();

			if (empty($postdata)) {
				throw new HTTPException\InternalServerErrorException('Missing postdata.');
			}

			self::$logger->info('Diaspora: Message is in the new format.');

			$msg = Diaspora::decodeRaw($postdata, $privKey);
		} else {

			$xml = urldecode($_POST['xml']);

			self::$logger->info('Diaspora: Decode message in the old format.');
			$msg = Diaspora::decode($xml, $privKey);

			if ($public && !$msg) {
				self::$logger->info('Diaspora: Decode message in the new format.');
				$msg = Diaspora::decodeRaw($xml, $privKey);
			}
		}

		self::$logger->info('Diaspora: Post decoded.');
		self::$logger->debug('Diaspora: Decoded message.', ['msg' => $msg]);

		if (!is_array($msg)) {
			throw new HTTPException\InternalServerErrorException('Message is not an array.');
		}

		return $msg;
	}
}