<?php
  
  namespace OCA\Files_Sharing;
  
  use OC_Config;
  use PasswordHash;
  
  class Helper {
  
  	public static function registerHooks() {
  		\OCP\Util::connectHook('OC_Filesystem', 'setup', '\OC\Files\Storage\Shared', 'setup');
  		\OCP\Util::connectHook('OC_Filesystem', 'setup', '\OCA\Files_Sharing\External\Manager', 'setup');
  		\OCP\Util::connectHook('OC_Filesystem', 'post_write', '\OC\Files\Cache\Shared_Updater', 'writeHook');
  		\OCP\Util::connectHook('OC_Filesystem', 'post_delete', '\OC\Files\Cache\Shared_Updater', 'postDeleteHook');
  		\OCP\Util::connectHook('OC_Filesystem', 'delete', '\OC\Files\Cache\Shared_Updater', 'deleteHook');
  		\OCP\Util::connectHook('OC_Filesystem', 'post_rename', '\OC\Files\Cache\Shared_Updater', 'renameHook');
  		\OCP\Util::connectHook('OC_Appconfig', 'post_set_value', '\OCA\Files\Share\Maintainer', 'configChangeHook');
  
  		\OCP\Util::connectHook('OCP\Share', 'post_shared', '\OC\Files\Cache\Shared_Updater', 'postShareHook');
  		\OCP\Util::connectHook('OCP\Share', 'post_unshare', '\OC\Files\Cache\Shared_Updater', 'postUnshareHook');
  		\OCP\Util::connectHook('OCP\Share', 'post_unshareFromSelf', '\OC\Files\Cache\Shared_Updater', 'postUnshareFromSelfHook');
  	}
  
  	/**
  	 * Sets up the filesystem and user for public sharing
  	 * @param string $token string share token
  	 * @param string $relativePath optional path relative to the share
  	 * @param string $password optional password
  	 */
  	public static function setupFromToken($token, $relativePath = null, $password = null) {
  		\OC_User::setIncognitoMode(true);
  
  		$linkItem = \OCP\Share::getShareByToken($token, !$password);
  		if($linkItem === false || ($linkItem['item_type'] !== 'file' && $linkItem['item_type'] !== 'folder')) {
  			\OC_Response::setStatus(404);
  			\OC_Log::write('core-preview', 'Passed token parameter is not valid', \OC_Log::DEBUG);
  			exit;
  		}
  
  		if(!isset($linkItem['uid_owner']) || !isset($linkItem['file_source'])) {
  			\OC_Response::setStatus(500);
  			\OC_Log::write('core-preview', 'Passed token seems to be valid, but it does not contain all necessary information . ("' . $token . '")', \OC_Log::WARN);
  			exit;
  		}
  
  		$rootLinkItem = \OCP\Share::resolveReShare($linkItem);
  		$path = null;
  		if (isset($rootLinkItem['uid_owner'])) {
  			\OCP\JSON::checkUserExists($rootLinkItem['uid_owner']);
  			\OC_Util::tearDownFS();
  			\OC_Util::setupFS($rootLinkItem['uid_owner']);
  			$path = \OC\Files\Filesystem::getPath($linkItem['file_source']);
  		}
  
  		if ($path === null) {
  			\OCP\Util::writeLog('share', 'could not resolve linkItem', \OCP\Util::DEBUG);
  			\OC_Response::setStatus(404);
  			\OCP\JSON::error(array('success' => false));
  			exit();
  		}
  
  		if (!isset($linkItem['item_type'])) {
  			\OCP\Util::writeLog('share', 'No item type set for share id: ' . $linkItem['id'], \OCP\Util::ERROR);
  			\OC_Response::setStatus(404);
  			\OCP\JSON::error(array('success' => false));
  			exit();
  		}
  
  		if (isset($linkItem['share_with'])) {
  			if (!self::authenticate($linkItem, $password)) {
  				\OC_Response::setStatus(403);
  				\OCP\JSON::error(array('success' => false));
  				exit();
  			}
  		}
  
  		$basePath = $path;
  
  		if ($relativePath !== null && \OC\Files\Filesystem::isReadable($basePath . $relativePath)) {
  			$path .= \OC\Files\Filesystem::normalizePath($relativePath);
  		}
  
  		return array(
  			'linkItem' => $linkItem,
  			'basePath' => $basePath,
  			'realPath' => $path
  		);
  	}
  
  	/**
  	 * Authenticate link item with the given password
  	 * or with the session if no password was given.
  	 * @param array $linkItem link item array
  	 * @param string $password optional password
  	 *
  	 * @return boolean true if authorized, false otherwise
  	 */
  	public static function authenticate($linkItem, $password) {
  		if ($password !== null) {
  			if ($linkItem['share_type'] == \OCP\Share::SHARE_TYPE_LINK) {
  				// Check Password
  				$forcePortable = (CRYPT_BLOWFISH != 1);
  				$hasher = new PasswordHash(8, $forcePortable);
  				if (!($hasher->CheckPassword($password.OC_Config::getValue('passwordsalt', ''),
  											 $linkItem['share_with']))) {
  					return false;
  				} else {
  					// Save item id in session for future requests
  					\OC::$session->set('public_link_authenticated', $linkItem['id']);
  				}
  			} else {
  				\OCP\Util::writeLog('share', 'Unknown share type '.$linkItem['share_type']
  					.' for share id '.$linkItem['id'], \OCP\Util::ERROR);
  				return false;
  			}
  
  		}
  		else {
  			// not authenticated ?
  			if ( ! \OC::$session->exists('public_link_authenticated')
  				|| \OC::$session->get('public_link_authenticated') !== $linkItem['id']) {
  				return false;
  			}
  		}
  		return true;
  	}
  
  	public static function getSharesFromItem($target) {
  		$result = array();
  		$owner = \OC\Files\Filesystem::getOwner($target);
  		\OC\Files\Filesystem::initMountPoints($owner);
  		$info = \OC\Files\Filesystem::getFileInfo($target);
  		$ownerView = new \OC\Files\View('/'.$owner.'/files');
  		if ( $owner != \OCP\User::getUser() ) {
  			$path = $ownerView->getPath($info['fileid']);
  		} else {
  			$path = $target;
  		}
  
  
  		$ids = array();
  		while ($path !== dirname($path)) {
  			$info = $ownerView->getFileInfo($path);
  			if ($info instanceof \OC\Files\FileInfo) {
  				$ids[] = $info['fileid'];
  			} else {
  				\OCP\Util::writeLog('sharing', 'No fileinfo available for: ' . $path, \OCP\Util::WARN);
  			}
  			$path = dirname($path);
  		}
  
  		if (!empty($ids)) {
  
  			$idList = array_chunk($ids, 99, true);
  
  			foreach ($idList as $subList) {
  				$statement = "SELECT `share_with`, `share_type`, `file_target` FROM `*PREFIX*share` WHERE `file_source` IN (" . implode(',', $subList) . ") AND `share_type` IN (0, 1, 2)";
  				$query = \OCP\DB::prepare($statement);
  				$r = $query->execute();
  				$result = array_merge($result, $r->fetchAll());
  			}
  		}
  
  		return $result;
  	}
  
  	public static function getUidAndFilename($filename) {
  		$uid = \OC\Files\Filesystem::getOwner($filename);
  		\OC\Files\Filesystem::initMountPoints($uid);
  		if ( $uid != \OCP\User::getUser() ) {
  			$info = \OC\Files\Filesystem::getFileInfo($filename);
  			$ownerView = new \OC\Files\View('/'.$uid.'/files');
  			$filename = $ownerView->getPath($info['fileid']);
  		}
  		return array($uid, $filename);
  	}
  
  	/**
  	 * Format a path to be relative to the /user/files/ directory
  	 * @param string $path the absolute path
  	 * @return string e.g. turns '/admin/files/test.txt' into 'test.txt'
  	 */
  	public static function stripUserFilesPath($path) {
  		$trimmed = ltrim($path, '/');
  		$split = explode('/', $trimmed);
  
  		// it is not a file relative to data/user/files
  		if (count($split) < 3 || $split[1] !== 'files') {
  			return false;
  		}
  
  		$sliced = array_slice($split, 2);
  		$relPath = implode('/', $sliced);
  
  		return $relPath;
  	}
  
  	/**
  	 * check if file name already exists and generate unique target
  	 *
  	 * @param string $path
  	 * @param array $excludeList
  	 * @param \OC\Files\View $view
  	 * @return string $path
  	 */
  	public static function generateUniqueTarget($path, $excludeList, $view) {
  		$pathinfo = pathinfo($path);
  		$ext = (isset($pathinfo['extension'])) ? '.'.$pathinfo['extension'] : '';
  		$name = $pathinfo['filename'];
  		$dir = $pathinfo['dirname'];
  		$i = 2;
  		while ($view->file_exists($path) || in_array($path, $excludeList)) {
  			$path = \OC\Files\Filesystem::normalizePath($dir . '/' . $name . ' ('.$i.')' . $ext);
  			$i++;
  		}
  
  		return $path;
  	}
  
  	/**
  	 * allow users from other ownCloud instances to mount public links share by this instance
  	 * @return bool
  	 */
  	public static function isOutgoingServer2serverShareEnabled() {
  		$appConfig = \OC::$server->getAppConfig();
  		$result = $appConfig->getValue('files_sharing', 'outgoing_server2server_share_enabled', 'yes');
  		return ($result === 'yes') ? true : false;
  	}
  
  	/**
  	 * allow user to mount public links from onther ownClouds
  	 * @return bool
  	 */
  	public static function isIncomingServer2serverShareEnabled() {
  		$appConfig = \OC::$server->getAppConfig();
  		$result = $appConfig->getValue('files_sharing', 'incoming_server2server_share_enabled', 'yes');
  		return ($result === 'yes') ? true : false;
  	}
  
  }