<?php

/**
 * ownCloud
 *
 * @author Florin Peter
 * @copyright 2013 Florin Peter <owncloud@florin-peter.de>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or any later version.
 *
 * This library 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 library.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

namespace OCA\Encryption;

	/**
	 * @brief Class to manage registration of hooks an various helper methods
	 */
/**
 * Class Helper
 * @package OCA\Encryption
 */
class Helper
{

	/**
	 * @brief register share related hooks
	 *
	 */
	public static function registerShareHooks() {

		\OCP\Util::connectHook( 'OCP\Share', 'pre_shared', 'OCA\Encryption\Hooks', 'preShared' );
		\OCP\Util::connectHook( 'OCP\Share', 'post_shared', 'OCA\Encryption\Hooks', 'postShared' );
		\OCP\Util::connectHook( 'OCP\Share', 'post_unshare', 'OCA\Encryption\Hooks', 'postUnshare' );
	}

	/**
	 * @brief register user related hooks
	 *
	 */
	public static function registerUserHooks() {

		\OCP\Util::connectHook( 'OC_User', 'post_login', 'OCA\Encryption\Hooks', 'login' );
		\OCP\Util::connectHook( 'OC_User', 'post_setPassword', 'OCA\Encryption\Hooks', 'setPassphrase' );
		\OCP\Util::connectHook( 'OC_User', 'post_createUser', 'OCA\Encryption\Hooks', 'postCreateUser' );
		\OCP\Util::connectHook( 'OC_User', 'post_deleteUser', 'OCA\Encryption\Hooks', 'postDeleteUser' );
	}

	/**
	 * @brief register filesystem related hooks
	 *
	 */
	public static function registerFilesystemHooks() {

		\OCP\Util::connectHook( 'OC_Filesystem', 'post_rename', 'OCA\Encryption\Hooks', 'postRename' );
	}

	/**
	 * @brief setup user for files_encryption
	 *
	 * @param Util $util
	 * @param string $password
	 * @return bool
	 */
	public static function setupUser( $util, $password ) {
		// Check files_encryption infrastructure is ready for action
		if ( !$util->ready() ) {

			\OC_Log::write( 'Encryption library', 'User account "' . $util->getUserId() . '" is not ready for encryption; configuration started', \OC_Log::DEBUG );

			if ( !$util->setupServerSide( $password ) ) {
				return false;
			}
		}

		return true;
	}

	/**
	 * @brief enable recovery
	 *
	 * @param $recoveryKeyId
	 * @param $recoveryPassword
	 * @internal param \OCA\Encryption\Util $util
	 * @internal param string $password
	 * @return bool
	 */
	public static function adminEnableRecovery( $recoveryKeyId, $recoveryPassword ) {
		$view = new \OC\Files\View( '/' );

		if ( $recoveryKeyId === null ) {
			$recoveryKeyId = 'recovery_' . substr( md5( time() ), 0, 8 );
			\OC_Appconfig::setValue( 'files_encryption', 'recoveryKeyId', $recoveryKeyId );
		}

		if ( !$view->is_dir( '/owncloud_private_key' ) ) {
			$view->mkdir( '/owncloud_private_key' );
		}

		if (
			( !$view->file_exists( "/public-keys/" . $recoveryKeyId . ".public.key" )
				|| !$view->file_exists( "/owncloud_private_key/" . $recoveryKeyId . ".private.key" ) )
		) {

			$keypair = \OCA\Encryption\Crypt::createKeypair();

			\OC_FileProxy::$enabled = false;

			// Save public key

			if ( !$view->is_dir( '/public-keys' ) ) {
				$view->mkdir( '/public-keys' );
			}

			$view->file_put_contents( '/public-keys/' . $recoveryKeyId . '.public.key', $keypair['publicKey'] );

			// Encrypt private key empthy passphrase
			$encryptedPrivateKey = \OCA\Encryption\Crypt::symmetricEncryptFileContent( $keypair['privateKey'], $recoveryPassword );

			// Save private key
			$view->file_put_contents( '/owncloud_private_key/' . $recoveryKeyId . '.private.key', $encryptedPrivateKey );

			// create control file which let us check later on if the entered password was correct.
			$encryptedControlData = \OCA\Encryption\Crypt::keyEncrypt( "ownCloud", $keypair['publicKey'] );
			if ( !$view->is_dir( '/control-file' ) ) {
				$view->mkdir( '/control-file' );
			}
			$view->file_put_contents( '/control-file/controlfile.enc', $encryptedControlData );

			\OC_FileProxy::$enabled = true;

			// Set recoveryAdmin as enabled
			\OC_Appconfig::setValue( 'files_encryption', 'recoveryAdminEnabled', 1 );

			$return = true;

		} else { // get recovery key and check the password
			$util = new \OCA\Encryption\Util( new \OC_FilesystemView( '/' ), \OCP\User::getUser() );
			$return = $util->checkRecoveryPassword( $recoveryPassword );
			if ( $return ) {
				\OC_Appconfig::setValue( 'files_encryption', 'recoveryAdminEnabled', 1 );
			}
		}

		return $return;
	}


	/**
	 * @brief disable recovery
	 *
	 * @param $recoveryPassword
	 * @return bool
	 */
	public static function adminDisableRecovery( $recoveryPassword ) {
		$util = new Util( new \OC_FilesystemView( '/' ), \OCP\User::getUser() );
		$return = $util->checkRecoveryPassword( $recoveryPassword );

		if ( $return ) {
			// Set recoveryAdmin as disabled
			\OC_Appconfig::setValue( 'files_encryption', 'recoveryAdminEnabled', 0 );
		}

		return $return;
	}


	/**
	 * @brief checks if access is public/anonymous user
	 * @return bool
	 */
	public static function isPublicAccess() {
		if (\OCP\USER::getUser() === false
			|| (isset($_GET['service']) && $_GET['service'] == 'files'
				&& isset($_GET['t']))
		) {
			return true;
		} else {
			return false;
		}
	}
}