<?php

declare(strict_types=1);

/**
 * SPDX-FileCopyrightText: 2019-2024 Nextcloud GmbH and Nextcloud contributors
 * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
 * SPDX-License-Identifier: AGPL-3.0-only
 */

namespace OCA\Encryption\Crypto;

use OCA\Encryption\Exceptions\PrivateKeyMissingException;
use OCA\Encryption\KeyManager;
use OCA\Encryption\Session;
use OCA\Encryption\Util;
use Symfony\Component\Console\Helper\QuestionHelper;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\Question\ConfirmationQuestion;
use Symfony\Component\Console\Question\Question;

class DecryptAll {
	public function __construct(
		protected Util $util,
		protected KeyManager $keyManager,
		protected Crypt $crypt,
		protected Session $session,
		protected QuestionHelper $questionHelper,
	) {
	}

	/**
	 * prepare encryption module to decrypt all files
	 */
	public function prepare(InputInterface $input, OutputInterface $output, ?string $user): bool {
		$question = new Question('Please enter the recovery key password: ');

		if ($this->util->isMasterKeyEnabled()) {
			$output->writeln('Use master key to decrypt all files');
			$user = $this->keyManager->getMasterKeyId();
			$password = $this->keyManager->getMasterKeyPassword();
		} else {
			$recoveryKeyId = $this->keyManager->getRecoveryKeyId();
			if ($user !== null && $user !== '') {
				$output->writeln('You can only decrypt the users files if you know');
				$output->writeln('the users password or if they activated the recovery key.');
				$output->writeln('');
				$questionUseLoginPassword = new ConfirmationQuestion(
					'Do you want to use the users login password to decrypt all files? (y/n) ',
					false
				);
				$useLoginPassword = $this->questionHelper->ask($input, $output, $questionUseLoginPassword);
				if ($useLoginPassword) {
					$question = new Question('Please enter the user\'s login password: ');
				} elseif ($this->util->isRecoveryEnabledForUser($user) === false) {
					$output->writeln('No recovery key available for user ' . $user);
					return false;
				} else {
					$user = $recoveryKeyId;
				}
			} else {
				$output->writeln('You can only decrypt the files of all users if the');
				$output->writeln('recovery key is enabled by the admin and activated by the users.');
				$output->writeln('');
				$user = $recoveryKeyId;
			}

			$question->setHidden(true);
			$question->setHiddenFallback(false);
			$password = $this->questionHelper->ask($input, $output, $question);
		}

		$privateKey = $this->getPrivateKey($user, $password);
		if ($privateKey !== false) {
			$this->updateSession($user, $privateKey);
			return true;
		} else {
			$output->writeln('Could not decrypt private key, maybe you entered the wrong password?');
		}


		return false;
	}

	/**
	 * get the private key which will be used to decrypt all files
	 *
	 * @throws PrivateKeyMissingException
	 */
	protected function getPrivateKey(string $user, string $password): string|false {
		$recoveryKeyId = $this->keyManager->getRecoveryKeyId();
		$masterKeyId = $this->keyManager->getMasterKeyId();
		if ($user === $recoveryKeyId) {
			$recoveryKey = $this->keyManager->getSystemPrivateKey($recoveryKeyId);
			$privateKey = $this->crypt->decryptPrivateKey($recoveryKey, $password);
		} elseif ($user === $masterKeyId) {
			$masterKey = $this->keyManager->getSystemPrivateKey($masterKeyId);
			$privateKey = $this->crypt->decryptPrivateKey($masterKey, $password, $masterKeyId);
		} else {
			$userKey = $this->keyManager->getPrivateKey($user);
			$privateKey = $this->crypt->decryptPrivateKey($userKey, $password, $user);
		}

		return $privateKey;
	}

	protected function updateSession(string $user, string $privateKey): void {
		$this->session->prepareDecryptAll($user, $privateKey);
	}
}