<?php

  $installedVersion = OCP\Config::getAppValue('files_sharing', 'installed_version');

  
  if (version_compare($installedVersion, '0.5', '<')) {
  	updateFilePermissions();
  }
  
  if (version_compare($installedVersion, '0.4', '<')) {
  	removeSharedFolder();
  }
  
  // clean up oc_share table from files which are no longer exists
  if (version_compare($installedVersion, '0.3.5.6', '<')) {
  	\OC\Files\Cache\Shared_Updater::fixBrokenSharesOnAppUpdate();
  }
  
  
  /**
   * it is no longer possible to share single files with delete permissions. User
   * should only be able to unshare single files but never to delete them.
   */
  function updateFilePermissions($chunkSize = 99) {
  	$query = OCP\DB::prepare('SELECT * FROM `*PREFIX*share` WHERE `item_type` = ?');
  	$result = $query->execute(array('file'));
  
  	$updatedRows = array();
  
  	while ($row = $result->fetchRow()) {
  		if ($row['permissions'] & \OCP\PERMISSION_DELETE) {
  			$updatedRows[$row['id']] = (int)$row['permissions'] & ~\OCP\PERMISSION_DELETE;
  		}
  	}
  
  	$connection = \OC_DB::getConnection();
  	$chunkedPermissionList = array_chunk($updatedRows, $chunkSize, true);
  
  	foreach ($chunkedPermissionList as $subList) {
  		$statement = "UPDATE `*PREFIX*share` SET `permissions` = CASE `id` ";
  		//update share table
  		$ids = implode(',', array_keys($subList));
  		foreach ($subList as $id => $permission) {
  			$statement .= "WHEN " . $connection->quote($id, \PDO::PARAM_INT) . " THEN " . $permission . " ";
  		}
  		$statement .= ' END WHERE `id` IN (' . $ids . ')';
  
  		$query = OCP\DB::prepare($statement);
  		$query->execute();
  	}
  
  }
  
  /**
   * update script for the removal of the logical "Shared" folder, we create physical "Shared" folder and
   * update the users file_target so that it doesn't make any difference for the user
   * @note parameters are just for testing, please ignore them
   */
  function removeSharedFolder($mkdirs = true, $chunkSize = 99) {
  	$query = OCP\DB::prepare('SELECT * FROM `*PREFIX*share`');

  	$result = $query->execute();

  	$view = new \OC\Files\View('/');
  	$users = array();
  	$shares = array();
  	//we need to set up user backends

  	OC_User::useBackend(new OC_User_Database());
  	OC_Group::useBackend(new OC_Group_Database());
  	OC_App::loadApps(array('authentication'));

  	//we need to set up user backends, otherwise creating the shares will fail with "because user does not exist"

  	while ($row = $result->fetchRow()) {

  		//collect all user shares
  		if ((int)$row['share_type'] === 0 && ($row['item_type'] === 'file' || $row['item_type'] === 'folder')) {
  			$users[] = $row['share_with'];
  			$shares[$row['id']] = $row['file_target'];
  		} else if ((int)$row['share_type'] === 1 && ($row['item_type'] === 'file' || $row['item_type'] === 'folder')) {
  			//collect all group shares
  			$users = array_merge($users, \OC_group::usersInGroup($row['share_with']));
  			$shares[$row['id']] = $row['file_target'];
  		} else if ((int)$row['share_type'] === 2) {
  			$shares[$row['id']] = $row['file_target'];
  		}
  	}
  
  	$unique_users = array_unique($users);
  
  	if (!empty($unique_users) && !empty($shares)) {
  
  		// create folder Shared for each user
  
  		if ($mkdirs) {
  			foreach ($unique_users as $user) {
  				\OC\Files\Filesystem::initMountPoints($user);
  				if (!$view->file_exists('/' . $user . '/files/Shared')) {
  					$view->mkdir('/' . $user . '/files/Shared');

  				}

  			}

  		}

  		$chunkedShareList = array_chunk($shares, $chunkSize, true);
  		$connection = \OC_DB::getConnection();
  
  		foreach ($chunkedShareList as $subList) {

  			$statement = "UPDATE `*PREFIX*share` SET `file_target` = CASE `id` ";
  			//update share table
  			$ids = implode(',', array_keys($subList));
  			foreach ($subList as $id => $target) {
  				$statement .= "WHEN " . $connection->quote($id, \PDO::PARAM_INT) . " THEN " . $connection->quote('/Shared' . $target, \PDO::PARAM_STR);
  			}
  			$statement .= ' END WHERE `id` IN (' . $ids . ')';

  			$query = OCP\DB::prepare($statement);
  
  			$query->execute(array());

  		}

  		// set config to keep the Shared folder as the default location for new shares
  		\OCA\Files_Sharing\Helper::setShareFolder('/Shared');

  	}
  }