<?php

/**
 * RocketWeb
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Open Software License (OSL 3.0)
 * that is bundled with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://opensource.org/licenses/osl-3.0.php
 *
 * @category   RocketWeb
 * @package    RocketWeb_GoogleBaseFeedGenerator
 * @copyright  Copyright (c) 2011 RocketWeb (http://rocketweb.com)
 * @license    http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 * @author     RocketWeb
 */

class RocketWeb_GoogleBaseFeedGenerator_Model_Batch extends Varien_Object
{
	protected $total_items;
	protected $offset = 0;
	protected $limit = 1000;
	protected $started_at = 0;
	protected $ended_at = 0;
	
	public function _construct()
	{
		parent::_construct();
		//$this->started_at = Mage::getSingleton('core/date')->timestamp(time());
		$this->started_at = time();
		$this->setData('cdate', $this->started_at);
	}
	
	public function aquireLock()
	{
		if (!file_exists($this->getLockPath()))
		{
			$f = @fopen($this->getLockPath(), "w");
			@fclose($f);
			if (!file_exists($this->getLockPath()))
				Mage::throwException(sprintf('Can\'t create file', $this->getLockPath()));
		}
		
		if (($this->_locked = $this->isLocked()) == true)
		{
			$this->log(sprintf('Can\'t aquire lock for script [%s]', $this->getScheduleId()));
			return false;
		}
		
		$this->lock();
		return true;
	}
	
	public function isLocked()
	{
		$locked = false;
		$lock_data = $this->readFile();
		// Locked if another script is running.
		if ($lock_data['id'] != $this->getScheduleId() && $lock_data['status'] == Mage_Cron_Model_Schedule::STATUS_RUNNING)
		{
			$this->log(sprintf('Script [%s] is already running', $lock_data['id']));
			// Aquire lock if expired (expires in almost 24 hours)
			if (!$this->isLockExpired($lock_data['queue_started_at']))
			{
				$locked = true;
			}
			else
			{
				$this->log(sprintf(
					'Lock of script [%s] has expired at %s, script [%s] will aquire lock (cdate is [%s])',
					$lock_data['id'],
					date('Y-m-d H:i:s', date('Y-m-d 23:59:59', $this->getCdate())),
					$this->getScheduleId(),
					date('Y-m-d H:i:s', $this->started_at)
				));
			}
		}
		
		// Fail safe - don't allow to run too many times even if cron missed or unknown error was triggered in the past.
		if ($lock_data['offset'] > 0 && $lock_data['fail_safe'] >= ceil($this->total_items / $this->limit) + max(ceil(ceil($this->total_items / $this->limit) / 2), 2))
		{
			$locked = true;
			if (!$this->isLockExpired($lock_data['queue_started_at']))
			{
				$locked = false;
				$this->log(sprintf('Script was executed too many times %d', $lock_data['fail_safe']));
			}
		}
		
		// Allow only 1 complete feed generation in a single day.
		if ($this->getQueueFinished($lock_data['offset'], $this->total_items) && !$this->isLockExpired($lock_data['queue_started_at']))
		{
			$locked = true;
			$this->log(sprintf('Script %s can\'t run. The feed was completly generated once today %s', $this->getScheduleId(), date('Y-m-d')));
		}
		
		return $locked;
	}
	
	public function isLockExpired($time)
	{
		$expired = true;
		$cdate = $this->getCdate();
		$cday_s = mktime(0, 0, 0, date('m', $cdate), date('d', $cdate), date('Y', $cdate));
		$cday_e = mktime(23, 59, 59, date('m', $cdate), date('d', $cdate), date('Y', $cdate));
		if ($time >= $cday_s && $time <= $cday_e)
			$expired = false;
		return $expired;
	}
	
	protected function lock()
	{
		$lock_data = $this->readFile();
		
		$this->setIsNew(false);
		if ($lock_data['offset'] == 0)
			$this->setIsNew(true);
			
		if ($this->getQueueFinished($lock_data['offset'], $this->total_items))
		{
			$lock_data = $this->resetLockData();
			$this->setIsNew(true);
		}
		
		$lock_data['id'] = $this->getScheduleId();
		// Declare as processed to prevent loops by incrementing offset from the begining.
		$this->offset = $this->getNextOffset($lock_data['offset'], $this->limit);
		$lock_data['offset'] = $this->offset;
		$lock_data['total'] = $this->total_items;
		$lock_data['limit'] = $this->limit;
		$lock_data['started_at'] = $this->started_at;
		$lock_data['ended_at'] = 0;
		$lock_data['status'] = Mage_Cron_Model_Schedule::STATUS_RUNNING;
		$lock_data['fail_safe'] += 1;
		
		$this->writeFile($lock_data);
		$this->log(sprintf('Script %d aquired lock', $this->getScheduleId()));
		return $this;
	}
	
	public function releaseLock()
	{
		$this->unlock();
		return true;
	}
	
	public function getQueueFinished($offset, $total)
	{
		if ($offset >= $total)
			return true;
		return false;
	}
	
	protected function unlock()
	{
		$lock_data = $this->readFile();
		$lock_data['ended_at'] = time();
		$lock_data['status'] = Mage_Cron_Model_Schedule::STATUS_SUCCESS;
		$this->writeFile($lock_data);
		$this->log(sprintf('Script %d released lock', $this->getScheduleId()));
		return $this;
	}
	
	protected function getNextOffset($offset, $limit) { return $offset + $limit; }
	
	public function getEstimateJobs($past_runs)
	{
		$estimate = ceil($this->total_items / $this->limit) - $past_runs;
		$estimate = min($estimate, ceil($this->total_items / $this->limit) - $this->offset / $this->limit);
		return $estimate;
	}
	
	public function writeFile($mixed)
	{
		$mixed['updated_at'] = time();
		if (!is_writable($this->getLockPath()))
			Mage::throwException(sprintf('Can\t write to %s', $this->getLockPath()));
		if (file_put_contents($this->getLockPath(), @serialize($mixed), LOCK_EX) === false)
			Mage::throwException(sprintf('Error writing to %s', $this->getLockPath()));
		return $mixed;
	}
	
	public function readFile()
	{
		
		$mixed = file_get_contents($this->getLockPath());
		if ($mixed === false)
			Mage::throwException(sprintf('Error reading from %s', $this->getLockPath()));
		$mixed = @unserialize($mixed);
		if (empty($mixed))
		{
			$mixed = $this->resetLockData();
			$mixed['created_at'] = time();
		}
		return $mixed;
	}
	
	protected function resetLockData()
	{
		return array(
			'id'	      => false,
			'offset'	  => 0,
			'total'	 	  => $this->total_items,
			'limit'	 	  => $this->limit,
			'status'	  => Mage_Cron_Model_Schedule::STATUS_PENDING,
			'started_at'  => 0,
			'ended_at'	  => 0,
			'updated_at'  => 0,
			'queue_started_at' => time(),
			'fail_safe'	  => 0);
	}
	
    public function getLockPath()
    {
    	$fpath = rtrim(dirname($this->getGenerator()->getFeedPath()), DS);
    	$fpath .= DS.sprintf($this->getConfigVar('lock_filename'), $this->getStoreCode());
    	return $fpath;
    }
    
    public function setTotalItems($value) { $this->total_items = (int) $value; }
    protected function setOffset($value) { $this->offset = (int) $value; }
    public function getOffset() { return $this->offset; }
    public function setLimit($value) { $this->limit = (int) $value; }
    public function getLimit() { return $this->limit; }
    
    public function getLocked() { return $this->_locked; }
    
    /**
     * @param string $key
     * @param string $section
     * @return mixed
     */
    public function getConfigVar($key, $section = 'settings')
    {
    	return $this->getGenerator()->getConfigVar($key, $section);
    }
    
    /**
     * @return RocketWeb_GoogleBaseFeedGenerator_Model_Config
     */
    public function getConfig()
    {
    	return $this->getGenerator()->getConfig();
    }
    
    public function log($msg, $level = null)
    {
    	$this->getGenerator()->log($msg, $level);
    }
    
    /**
     * @return RocketWeb_GoogleBaseFeedGenerator_Model_Generator
     */
    public function getGenerator()
    {
    	return $this->getData('generator');
    }
}