<?php
  /**

   * Copyright (c) 2014 Robin Appelman <icewind@owncloud.com>

   * This file is licensed under the Affero General Public License version 3 or
   * later.
   * See the COPYING-README file.
   */
  
  namespace OC\BackgroundJob;

  use OCP\BackgroundJob\IJobList;
  
  class JobList implements IJobList {
  	/**
  	 * @var \OCP\IDBConnection
  	 */
  	private $conn;
  
  	/**
  	 * @var \OCP\IConfig $config
  	 */
  	private $config;
  
  	/**
  	 * @param \OCP\IDBConnection $conn
  	 * @param \OCP\IConfig $config
  	 */
  	public function __construct($conn, $config) {
  		$this->conn = $conn;
  		$this->config = $config;
  	}

  	/**
  	 * @param Job|string $job
  	 * @param mixed $argument
  	 */
  	public function add($job, $argument = null) {
  		if (!$this->has($job, $argument)) {
  			if ($job instanceof Job) {
  				$class = get_class($job);
  			} else {
  				$class = $job;
  			}
  			$argument = json_encode($argument);

  			$query = $this->conn->prepare('INSERT INTO `*PREFIX*jobs`(`class`, `argument`, `last_run`) VALUES(?, ?, 0)');

  			$query->execute(array($class, $argument));
  		}
  	}
  
  	/**
  	 * @param Job|string $job
  	 * @param mixed $argument
  	 */
  	public function remove($job, $argument = null) {
  		if ($job instanceof Job) {
  			$class = get_class($job);
  		} else {
  			$class = $job;
  		}
  		if (!is_null($argument)) {
  			$argument = json_encode($argument);

  			$query = $this->conn->prepare('DELETE FROM `*PREFIX*jobs` WHERE `class` = ? AND `argument` = ?');

  			$query->execute(array($class, $argument));
  		} else {

  			$query = $this->conn->prepare('DELETE FROM `*PREFIX*jobs` WHERE `class` = ?');

  			$query->execute(array($class));
  		}
  	}
  
  	/**
  	 * check if a job is in the list
  	 *

  	 * @param Job|string $job

  	 * @param mixed $argument
  	 * @return bool
  	 */
  	public function has($job, $argument) {
  		if ($job instanceof Job) {
  			$class = get_class($job);
  		} else {
  			$class = $job;
  		}
  		$argument = json_encode($argument);

  		$query = $this->conn->prepare('SELECT `id` FROM `*PREFIX*jobs` WHERE `class` = ? AND `argument` = ?');
  		$query->execute(array($class, $argument));
  		return (bool)$query->fetch();

  	}
  
  	/**
  	 * get all jobs in the list
  	 *
  	 * @return Job[]
  	 */
  	public function getAll() {

  		$query = $this->conn->prepare('SELECT `id`, `class`, `last_run`, `argument` FROM `*PREFIX*jobs`');
  		$query->execute();

  		$jobs = array();

  		while ($row = $query->fetch()) {
  			$job = $this->buildJob($row);
  			if ($job) {
  				$jobs[] = $job;
  			}

  		}
  		return $jobs;
  	}
  
  	/**
  	 * get the next job in the list
  	 *
  	 * @return Job
  	 */
  	public function getNext() {
  		$lastId = $this->getLastJob();

  		$query = $this->conn->prepare('SELECT `id`, `class`, `last_run`, `argument` FROM `*PREFIX*jobs` WHERE `id` > ? ORDER BY `id` ASC', 1);
  		$query->execute(array($lastId));
  		if ($row = $query->fetch()) {

  			return $this->buildJob($row);
  		} else {
  			//begin at the start of the queue

  			$query = $this->conn->prepare('SELECT `id`, `class`, `last_run`, `argument` FROM `*PREFIX*jobs` ORDER BY `id` ASC', 1);
  			$query->execute();
  			if ($row = $query->fetch()) {

  				return $this->buildJob($row);
  			} else {
  				return null; //empty job list
  			}
  		}
  	}
  
  	/**
  	 * @param int $id

  	 * @return Job|null

  	 */
  	public function getById($id) {

  		$query = $this->conn->prepare('SELECT `id`, `class`, `last_run`, `argument` FROM `*PREFIX*jobs` WHERE `id` = ?');
  		$query->execute(array($id));
  		if ($row = $query->fetch()) {

  			return $this->buildJob($row);
  		} else {
  			return null;
  		}
  	}
  
  	/**
  	 * get the job object from a row in the db
  	 *
  	 * @param array $row
  	 * @return Job
  	 */
  	private function buildJob($row) {
  		$class = $row['class'];
  		/**
  		 * @var Job $job
  		 */

  		if ($class === 'OC_Cache_FileGlobalGC') {
  			$class = '\OC\Cache\FileGlobalGC';
  		}
  		if (!class_exists($class)) {
  			// job from disabled app or old version of an app, no need to do anything
  			return null;
  		}

  		$job = new $class();
  		$job->setId($row['id']);
  		$job->setLastRun($row['last_run']);
  		$job->setArgument(json_decode($row['argument'], true));
  		return $job;
  	}
  
  	/**
  	 * set the job that was last ran
  	 *
  	 * @param Job $job
  	 */
  	public function setLastJob($job) {

  		$this->config->setAppValue('backgroundjob', 'lastjob', $job->getId());

  	}
  
  	/**
  	 * get the id of the last ran job
  	 *

  	 * @return string

  	 */
  	public function getLastJob() {

  		return $this->config->getAppValue('backgroundjob', 'lastjob', 0);

  	}
  
  	/**
  	 * set the lastRun of $job to now
  	 *
  	 * @param Job $job
  	 */
  	public function setLastRun($job) {

  		$query = $this->conn->prepare('UPDATE `*PREFIX*jobs` SET `last_run` = ? WHERE `id` = ?');

  		$query->execute(array(time(), $job->getId()));
  	}
  }