<?php
  
  /**
   * ownCloud - Documents App
   *
   * @author Victor Dubiniuk
   * @copyright 2013 Victor Dubiniuk victor.dubiniuk@gmail.com
   *
   * This file is licensed under the Affero General Public License version 3 or
   * later.
   */
  
  namespace OCA\Documents;
  
  /**
   *  Session management 
   */
  class Db_Session extends \OCA\Documents\Db {
  
  	/**
  	 * DB table
  	 */
  	const DB_TABLE = '`*PREFIX*documents_session`';
  	protected $tableName  = '`*PREFIX*documents_session`';
  
  	protected $insertStatement  = 'INSERT INTO `*PREFIX*documents_session` (`es_id`, `genesis_url`, `genesis_hash`, `owner`, `file_id`)
  			VALUES (?, ?, ?, ?, ?)';
  	
  	protected $loadStatement = 'SELECT * FROM `*PREFIX*documents_session` WHERE `es_id`= ?';
  
  	/**
  	 * Start a editing session or return an existing one
  	 * @param string $uid of the user starting a session
  	 * @param \OCA\Documents\File $file - file object
  	 * @return array
  	 * @throws \Exception
  	 */
  	public static function start($uid, $file){
  		// Create a directory to store genesis
  		$genesis = new Genesis($file);
  		
  		list($ownerView, $path) = $file->getOwnerViewAndPath();
  		$oldSession = new Db_Session();
  		$oldSession->loadBy('file_id', $file->getFileId());
  		
  		//If there is no existing session we need to start a new one
  		if (!$oldSession->hasData()){
  			$newSession = new Db_Session(array(
  				$genesis->getPath(),
  				$genesis->getHash(),
  				$file->getOwner(),
  				$file->getFileId()
  			));
  			
  			if (!$newSession->insert()){
  				throw new \Exception('Failed to add session into database');
  			}
  		}
  		
  		$sessionData = $oldSession
  					->loadBy('file_id', $file->getFileId())
  					->getData()
  		;
  		
  		$memberColor = Helper::getMemberColor($uid);
  		$member = new Db_Member(array(
  			$sessionData['es_id'], 
  			$uid,
  			$memberColor,
  			time(),
  			intval($file->isPublicShare()),
  			$file->getToken()
  		));
  		
  		if ($member->insert()){
  			// Do we have OC_Avatar in out disposal?
  			if (!class_exists('\OC_Avatar') || \OC_Config::getValue('enable_avatars', true) !== true){
  				$imageUrl = 'data:image/gif;base64,R0lGODlhAQABAIAAAAAAAAAAACH5BAAAAAAALAAAAAABAAEAAAICTAEAOw==';
  			} else {
  				$imageUrl = $uid;
  			}
  
  			$displayName = $file->isPublicShare() ? $uid . ' ' . Db_Member::getGuestPostfix() : \OCP\User::getDisplayName($uid);
  			
  			$sessionData['member_id'] = (string) $member->getLastInsertId();
  			$op = new Db_Op();
  			$op->addMember(
  					$sessionData['es_id'],
  					$sessionData['member_id'],
  					$displayName,
  					$memberColor,
  					$imageUrl
  			);
  		} else {
  			throw new \Exception('Failed to add member into database');
  		}
  		
  		$sessionData['title'] = basename($path);
  		$sessionData['permissions'] = $ownerView->getFilePermissions($path);
  		
  		return $sessionData;
  	}
  	
  	public static function cleanUp($esId){
  		$session = new Db_Session();
  		$session->deleteBy('es_id', $esId);
  		
  		$member = new Db_Member();
  		$member->deleteBy('es_id', $esId);
  		
  		$op= new Db_Op();
  		$op->deleteBy('es_id', $esId);
  	}
  	
  	public function insert(){
  		$esId = $this->getUniqueSessionId();
  		array_unshift($this->data, $esId);
  		return parent::insert($this->data);
  	}
  	
  	public function updateGenesisHash($esId, $genesisHash){
  		return $this->execute(
  			'UPDATE `*PREFIX*documents_session` SET `genesis_hash`=? WHERE `es_id`=?',
  			array(
  				$genesisHash, $esId
  			)
  		);
  	}
  
  	public function getInfo($esId){
  		$result = $this->execute('
  			SELECT `s`.*, COUNT(`m`.`member_id`) AS `users`
  			FROM ' . $this->tableName . ' AS `s`
  			LEFT JOIN `*PREFIX*documents_member` AS `m` ON `s`.`es_id`=`m`.`es_id`
  				AND `m`.`status`=' . Db_Member::MEMBER_STATUS_ACTIVE . '
  				AND `m`.`uid` != ?
  			WHERE `s`.`es_id` = ?
  			GROUP BY `m`.`es_id`
  			',
  			array(
  					\OCP\User::getUser(),
  					$esId
  			)
  		);
  
  		$info = $result->fetchRow();
  		if (!is_array($info)){
  			$info = array();
  		}
  		return $info;
  	}
  
  	public function getInfoByFileId($fileIds){
  		if (!is_array($fileIds)){
  			return array();
  		}
  
  		$stmt = $this->buildInQuery('file_id', $fileIds);
  
  		$result = $this->execute('
  			SELECT `s`.*, COUNT(`m`.`member_id`) AS `users`
  			FROM ' . $this->tableName . ' AS `s`
  			LEFT JOIN `*PREFIX*documents_member` AS `m` ON `s`.`es_id`=`m`.`es_id`
  				AND `m`.`status`=' . Db_Member::MEMBER_STATUS_ACTIVE . '
  			WHERE `s`.`file_id` ' . $stmt .'
  			GROUP BY `m`.`es_id`',
  			$fileIds
  		);
  
  		$info = $result->fetchAll();
  		if (!is_array($info)){
  			$info = array();
  		}
  		return $info;
  	}
  
  	protected function getUniqueSessionId(){
  		$testSession = new Db_Session();
  		do{
  			$id = \OC_Util::generateRandomBytes(30);
  		} while ($testSession->load($id)->hasData());
  
  		return $id;
  	}
  }