<?php
/**
 * @copyright Copyright (c) 2016, ownCloud, Inc.
 *
 * @author Bjoern Schiessle <bjoern@schiessle.org>
 * @author Björn Schießle <bjoern@schiessle.org>
 * @author Christoph Wurst <christoph@winzerhof-wurst.at>
 * @author Kenneth Newwood <kenneth@newwood.name>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Roeland Jago Douma <roeland@famdouma.nl>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 *
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * 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, version 3,
 * along with this program. If not, see <http://www.gnu.org/licenses/>
 *
 */
namespace OCA\Encryption\Crypto;

use OC\Encryption\Exceptions\DecryptionFailedException;
use OC\Files\View;
use OCA\Encryption\KeyManager;
use OCA\Encryption\Users\Setup;
use OCA\Encryption\Util;
use OCP\IConfig;
use OCP\IL10N;
use OCP\IUser;
use OCP\IUserManager;
use OCP\L10N\IFactory;
use OCP\Mail\Headers\AutoSubmitted;
use OCP\Mail\IMailer;
use OCP\Security\ISecureRandom;
use Symfony\Component\Console\Helper\ProgressBar;
use Symfony\Component\Console\Helper\QuestionHelper;
use Symfony\Component\Console\Helper\Table;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\Question\ConfirmationQuestion;

class EncryptAll {

	/** @var Setup */
	protected $userSetup;

	/** @var IUserManager */
	protected $userManager;

	/** @var View */
	protected $rootView;

	/** @var KeyManager */
	protected $keyManager;

	/** @var Util */
	protected $util;

	/** @var array  */
	protected $userPasswords;

	/** @var  IConfig */
	protected $config;

	/** @var IMailer */
	protected $mailer;

	/** @var  IL10N */
	protected $l;

	/** @var  IFactory */
	protected $l10nFactory;

	/** @var  QuestionHelper */
	protected $questionHelper;

	/** @var  OutputInterface */
	protected $output;

	/** @var  InputInterface */
	protected $input;

	/** @var ISecureRandom */
	protected $secureRandom;

	public function __construct(
		Setup $userSetup,
		IUserManager $userManager,
		View $rootView,
		KeyManager $keyManager,
		Util $util,
		IConfig $config,
		IMailer $mailer,
		IL10N $l,
		IFactory $l10nFactory,
		QuestionHelper $questionHelper,
		ISecureRandom $secureRandom
	) {
		$this->userSetup = $userSetup;
		$this->userManager = $userManager;
		$this->rootView = $rootView;
		$this->keyManager = $keyManager;
		$this->util = $util;
		$this->config = $config;
		$this->mailer = $mailer;
		$this->l = $l;
		$this->l10nFactory = $l10nFactory;
		$this->questionHelper = $questionHelper;
		$this->secureRandom = $secureRandom;
		// store one time passwords for the users
		$this->userPasswords = [];
	}

	/**
	 * start to encrypt all files
	 *
	 * @param InputInterface $input
	 * @param OutputInterface $output
	 */
	public function encryptAll(InputInterface $input, OutputInterface $output) {
		$this->input = $input;
		$this->output = $output;

		$headline = 'Encrypt all files with the ' . Encryption::DISPLAY_NAME;
		$this->output->writeln("\n");
		$this->output->writeln($headline);
		$this->output->writeln(str_pad('', strlen($headline), '='));
		$this->output->writeln("\n");

		if ($this->util->isMasterKeyEnabled()) {
			$this->output->writeln('Use master key to encrypt all files.');
			$this->keyManager->validateMasterKey();
		} else {
			//create private/public keys for each user and store the private key password
			$this->output->writeln('Create key-pair for every user');
			$this->output->writeln('------------------------------');
			$this->output->writeln('');
			$this->output->writeln('This module will encrypt all files in the users files folder initially.');
			$this->output->writeln('Already existing versions and files in the trash bin will not be encrypted.');
			$this->output->writeln('');
			$this->createKeyPairs();
		}


		// output generated encryption key passwords
		if ($this->util->isMasterKeyEnabled() === false) {
			//send-out or display password list and write it to a file
			$this->output->writeln("\n");
			$this->output->writeln('Generated encryption key passwords');
			$this->output->writeln('----------------------------------');
			$this->output->writeln('');
			$this->outputPasswords();
		}

		//setup users file system and encrypt all files one by one (take should encrypt setting of storage into account)
		$this->output->writeln("\n");
		$this->output->writeln('Start to encrypt users files');
		$this->output->writeln('----------------------------');
		$this->output->writeln('');
		$this->encryptAllUsersFiles();
		$this->output->writeln("\n");
	}

	/**
	 * create key-pair for every user
	 */
	protected function createKeyPairs() {
		$this->output->writeln("\n");
		$progress = new ProgressBar($this->output);
		$progress->setFormat(" %message% \n [%bar%]");
		$progress->start();

		foreach ($this->userManager->getBackends() as $backend) {
			$limit = 500;
			$offset = 0;
			do {
				$users = $backend->getUsers('', $limit, $offset);
				foreach ($users as $user) {
					if ($this->keyManager->userHasKeys($user) === false) {
						$progress->setMessage('Create key-pair for ' . $user);
						$progress->advance();
						$this->setupUserFS($user);
						$password = $this->generateOneTimePassword($user);
						$this->userSetup->setupUser($user, $password);
					} else {
						// users which already have a key-pair will be stored with a
						// empty password and filtered out later
						$this->userPasswords[$user] = '';
					}
				}
				$offset += $limit;
			} while (count($users) >= $limit);
		}

		$progress->setMessage('Key-pair created for all users');
		$progress->finish();
	}

	/**
	 * iterate over all user and encrypt their files
	 */
	protected function encryptAllUsersFiles() {
		$this->output->writeln("\n");
		$progress = new ProgressBar($this->output);
		$progress->setFormat(" %message% \n [%bar%]");
		$progress->start();
		$numberOfUsers = count($this->userPasswords);
		$userNo = 1;
		if ($this->util->isMasterKeyEnabled()) {
			$this->encryptAllUserFilesWithMasterKey($progress);
		} else {
			foreach ($this->userPasswords as $uid => $password) {
				$userCount = "$uid ($userNo of $numberOfUsers)";
				$this->encryptUsersFiles($uid, $progress, $userCount);
				$userNo++;
			}
		}
		$progress->setMessage("all files encrypted");
		$progress->finish();
	}

	/**
	 * encrypt all user files with the master key
	 *
	 * @param ProgressBar $progress
	 */
	protected function encryptAllUserFilesWithMasterKey(ProgressBar $progress) {
		$userNo = 1;
		foreach ($this->userManager->getBackends() as $backend) {
			$limit = 500;
			$offset = 0;
			do {
				$users = $backend->getUsers('', $limit, $offset);
				foreach ($users as $user) {
					$userCount = "$user ($userNo)";
					$this->encryptUsersFiles($user, $progress, $userCount);
					$userNo++;
				}
				$offset += $limit;
			} while (count($users) >= $limit);
		}
	}

	/**
	 * encrypt files from the given user
	 *
	 * @param string $uid
	 * @param ProgressBar $progress
	 * @param string $userCount
	 */
	protected function encryptUsersFiles($uid, ProgressBar $progress, $userCount) {
		$this->setupUserFS($uid);
		$directories = [];
		$directories[] = '/' . $uid . '/files';

		while ($root = array_pop($directories)) {
			$content = $this->rootView->getDirectoryContent($root);
			foreach ($content as $file) {
				$path = $root . '/' . $file['name'];
				if ($this->rootView->is_dir($path)) {
					$directories[] = $path;
					continue;
				} else {
					$progress->setMessage("encrypt files for user $userCount: $path");
					$progress->advance();
					if ($this->encryptFile($path) === false) {
						$progress->setMessage("encrypt files for user $userCount: $path (already encrypted)");
						$progress->advance();
					}
				}
			}
		}
	}

	/**
	 * encrypt file
	 *
	 * @param string $path
	 * @return bool
	 */
	protected function encryptFile($path) {

		// skip already encrypted files
		$fileInfo = $this->rootView->getFileInfo($path);
		if ($fileInfo !== false && $fileInfo->isEncrypted()) {
			return true;
		}

		$source = $path;
		$target = $path . '.encrypted.' . time();

		try {
			$this->rootView->copy($source, $target);
			$this->rootView->rename($target, $source);
		} catch (DecryptionFailedException $e) {
			if ($this->rootView->file_exists($target)) {
				$this->rootView->unlink($target);
			}
			return false;
		}

		return true;
	}

	/**
	 * output one-time encryption passwords
	 */
	protected function outputPasswords() {
		$table = new Table($this->output);
		$table->setHeaders(['Username', 'Private key password']);

		//create rows
		$newPasswords = [];
		$unchangedPasswords = [];
		foreach ($this->userPasswords as $uid => $password) {
			if (empty($password)) {
				$unchangedPasswords[] = $uid;
			} else {
				$newPasswords[] = [$uid, $password];
			}
		}

		if (empty($newPasswords)) {
			$this->output->writeln("\nAll users already had a key-pair, no further action needed.\n");
			return;
		}

		$table->setRows($newPasswords);
		$table->render();

		if (!empty($unchangedPasswords)) {
			$this->output->writeln("\nThe following users already had a key-pair which was reused without setting a new password:\n");
			foreach ($unchangedPasswords as $uid) {
				$this->output->writeln("    $uid");
			}
		}

		$this->writePasswordsToFile($newPasswords);

		$this->output->writeln('');
		$question = new ConfirmationQuestion('Do you want to send the passwords directly to the users by mail? (y/n) ', false);
		if ($this->questionHelper->ask($this->input, $this->output, $question)) {
			$this->sendPasswordsByMail();
		}
	}

	/**
	 * write one-time encryption passwords to a csv file
	 *
	 * @param array $passwords
	 */
	protected function writePasswordsToFile(array $passwords) {
		$fp = $this->rootView->fopen('oneTimeEncryptionPasswords.csv', 'w');
		foreach ($passwords as $pwd) {
			fputcsv($fp, $pwd);
		}
		fclose($fp);
		$this->output->writeln("\n");
		$this->output->writeln('A list of all newly created passwords was written to data/oneTimeEncryptionPasswords.csv');
		$this->output->writeln('');
		$this->output->writeln('Each of these users need to login to the web interface, go to the');
		$this->output->writeln('personal settings section "basic encryption module" and');
		$this->output->writeln('update the private key password to match the login password again by');
		$this->output->writeln('entering the one-time password into the "old log-in password" field');
		$this->output->writeln('and their current login password');
	}

	/**
	 * setup user file system
	 *
	 * @param string $uid
	 */
	protected function setupUserFS($uid) {
		\OC_Util::tearDownFS();
		\OC_Util::setupFS($uid);
	}

	/**
	 * generate one time password for the user and store it in a array
	 *
	 * @param string $uid
	 * @return string password
	 */
	protected function generateOneTimePassword($uid) {
		$password = $this->secureRandom->generate(16, ISecureRandom::CHAR_HUMAN_READABLE);
		$this->userPasswords[$uid] = $password;
		return $password;
	}

	/**
	 * send encryption key passwords to the users by mail
	 */
	protected function sendPasswordsByMail() {
		$noMail = [];

		$this->output->writeln('');
		$progress = new ProgressBar($this->output, count($this->userPasswords));
		$progress->start();

		foreach ($this->userPasswords as $uid => $password) {
			$progress->advance();
			if (!empty($password)) {
				$recipient = $this->userManager->get($uid);
				if (!$recipient instanceof IUser) {
					continue;
				}

				$recipientDisplayName = $recipient->getDisplayName();
				$to = $recipient->getEMailAddress();

				if ($to === '' || $to === null) {
					$noMail[] = $uid;
					continue;
				}

				$l = $this->l10nFactory->get('encryption', $this->l10nFactory->getUserLanguage($recipient));

				$template = $this->mailer->createEMailTemplate('encryption.encryptAllPassword', [
					'user' => $recipient->getUID(),
					'password' => $password,
				]);

				$template->setSubject($l->t('one-time password for server-side-encryption'));
				// 'Hey there,<br><br>The administration enabled server-side-encryption. Your files were encrypted using the password <strong>%s</strong>.<br><br>
				// Please login to the web interface, go to the section "Basic encryption module" of your personal settings and update your encryption password by entering this password into the "Old log-in password" field and your current login-password.<br><br>'
				$template->addHeader();
				$template->addHeading($l->t('Encryption password'));
				$template->addBodyText(
					$l->t('The administration enabled server-side-encryption. Your files were encrypted using the password <strong>%s</strong>.', [htmlspecialchars($password)]),
					$l->t('The administration enabled server-side-encryption. Your files were encrypted using the password "%s".', $password)
				);
				$template->addBodyText(
					$l->t('Please login to the web interface, go to the "Security" section of your personal settings and update your encryption password by entering this password into the "Old login password" field and your current login password.')
				);
				$template->addFooter();

				// send it out now
				try {
					$message = $this->mailer->createMessage();
					$message->setTo([$to => $recipientDisplayName]);
					$message->useTemplate($template);
					$message->setAutoSubmitted(AutoSubmitted::VALUE_AUTO_GENERATED);
					$this->mailer->send($message);
				} catch (\Exception $e) {
					$noMail[] = $uid;
				}
			}
		}

		$progress->finish();

		if (empty($noMail)) {
			$this->output->writeln("\n\nPassword successfully send to all users");
		} else {
			$table = new Table($this->output);
			$table->setHeaders(['Username', 'Private key password']);
			$this->output->writeln("\n\nCould not send password to following users:\n");
			$rows = [];
			foreach ($noMail as $uid) {
				$rows[] = [$uid, $this->userPasswords[$uid]];
			}
			$table->setRows($rows);
			$table->render();
		}
	}
}