<?php
	/**************************************************************************\
	* eGroupWare API - Timed Asynchron Services for eGroupWare                 *
	* Written by Ralf Becker <RalfBecker@outdoor-training.de>                  *
	* Class for creating cron-job like timed calls of eGroupWare methods       *
	* -------------------------------------------------------------------------*
	* This library is part of the eGroupWare API                               *
	* http://www.eGroupWare.org                                                *
	* ------------------------------------------------------------------------ *
	*  This program is free software; you can redistribute it and/or modify it *
	*  under the terms of the GNU General Public License as published by the   *
	*  Free Software Foundation; either version 2 of the License, or (at your  *
	*  option) any later version.                                              *
	\**************************************************************************/

	/* $Id$ */

	/*!
	@class asyncservice
	@author Ralf Becker
	@copyright GPL - GNU General Public License
	@abstract The class implements a general eGW service to execute callbacks at a given time.
	@discussion see http://www.egroupware.org/wiki/TimedAsyncServices
	*/
	class asyncservice
	{
		var $public_functions = array(
			'set_timer' => True,
			'check_run' => True,
			'cancel_timer' => True,
			'read'      => True,
			'install'   => True,
			'installed' => True,
			'last_check_run' => True
		);
		var $php = '';
		var $crontab = '';
		var $db;
		var $db_table = 'phpgw_async';
		var $debug = 0;
		
		/*!
		@function asyncservice
		@abstract constructor of the class
		*/
		function asyncservice()
		{
			$this->db = is_object($GLOBALS['phpgw']->db) ? $GLOBALS['phpgw']->db : $GLOBALS['phpgw_setup']->db;
			$this->db->set_app('phpgwapi');
				
			$this->cronline = PHPGW_SERVER_ROOT . '/phpgwapi/cron/asyncservices.php '.$GLOBALS['phpgw_info']['user']['domain'];
			
			$this->only_fallback = substr(php_uname(), 0, 7) == "Windows";	// atm cron-jobs dont work on win
		}

		/*!
		@function set_timer
		@abstract calculates the next run of the timer and puts that with the rest of the data in the db for later execution.
		@syntax set_timer($times,$id,$method,$data,$account_id=False)
		@param $times unix timestamp or array('min','hour','dow','day','month','year') with execution time. 
			Repeated events are possible to shedule by setting the array only partly, eg. 
			array('day' => 1) for first day in each month 0am or array('min' => '* /5', 'hour' => '9-17') 
			for every 5mins in the time from 9am to 5pm.
		@param $id unique id to cancel the request later, if necessary. Should be in a form like 
			eg. '<app><id>X' where id is the internal id of app and X might indicate the action.
		@param $method Method to be called via ExecMethod($method,$data). $method has the form 
			'<app>.<class>.<public function>'.
		@param $data This data is passed back when the method is called. It might simply be an 
			integer id, but it can also be a complete array.
		@param $account_id account_id, under which the methode should be called or False for the actual user
		@result False if $id already exists, else True	
		*/
		function set_timer($times,$id,$method,$data,$account_id=False)
		{
			if (empty($id) || empty($method) || $this->read($id) || 
			    !($next = $this->next_run($times)))
			{
				return False;
			}
			if ($account_id === False)
			{
				$account_id = $GLOBALS['phpgw_info']['user']['account_id'];
			}
			$job = array(
				'id'     => $id,
				'next'   => $next,
				'times'  => $times,
				'method' => $method,
				'data'   => $data,
				'account_id' => $account_id
			);
			$this->write($job);
			
			return True;
		}

		/*!
		@function next_run
		@abstract calculates the next execution time for $times
		@syntax next_run($times)
		@param $times unix timestamp or array('year'=>$year,'month'=>$month,'dow'=>$dow,'day'=>$day,'hour'=>$hour,'min'=>$min)
			with execution time. Repeated execution is possible to shedule by setting the array only partly, 
			eg. array('day' => 1) for first day in each month 0am or array('min' => '/5', 'hour' => '9-17') 
			for every 5mins in the time from 9am to 5pm. All not set units before the smallest one set, 
			are taken into account as every possible value, all after as the smallest possible value. 
		@param $debug if True some debug-messages about syntax-errors in $times are echoed
		@result a unix timestamp of the next execution time or False if no more executions
		*/
		function next_run($times,$debug=False)
		{
			if ($this->debug)
			{
				echo "<p>next_run("; print_r($times); ",'$debug')</p>\n";
				$debug = True;	// enable syntax-error messages too
			}
			$now = time();
			
			// $times is unix timestamp => if it's not expired return it, else False
			//
			if (!is_array($times))	
			{
				$next = (int)$times;

				return $next > $now ? $next : False;
			}
			// If an array is given, we have to enumerate the possible times first
			//
			$units = array(
				'year'  => 'Y',
				'month' => 'm',
				'day'   => 'd',
				'dow'   => 'w',
				'hour'  => 'H',
				'min'   => 'i'
			);
			$max_unit = array(
				'min'   => 59,
				'hour'  => 23,
				'dow'   => 6,
				'day'   => 31,
				'month' => 12,
				'year'  => date('Y')+10	// else */[0-9] would never stop returning numbers
			);
			$min_unit = array(
				'min'   => 0,
				'hour'  => 0,
				'dow'   => 0,
				'day'   => 1,
				'month' => 1,
				'year'  => date('Y')
			);

			// get the number of the first and last pattern set in $times, 
			// as empty patterns get enumerated before the the last pattern and 
			// get set to the minimum after
			//
			$n = $first_set = $last_set = 0;
			foreach($units as $u => $date_pattern)
			{
				++$n;
				if (isset($times[$u]))
				{
					$last_set = $n;

					if (!$first_set)
					{
						$first_set = $n;
					}
				}
			}

			// now we go through all units and enumerate all patterns and not set patterns
			// (as descript above), enumerations are arrays with unit-values as keys
			//
			$n = 0;
			foreach($units as $u => $date_pattern)
			{
				++$n;
				if ($this->debug) { echo "<p>n=$n, $u: isset(times[$u]="; print_r($times[$u]); echo ")=".(isset($times[$u])?'True':'False')."</p>\n"; }
				if (isset($times[$u]))
				{
					$time = explode(',',$times[$u]);

					$times[$u] = array();

					foreach($time as $t)
					{
						if (strstr($t,'-') !== False && strstr($t,'/') === False)
						{
							list($min,$max) = $arr = explode('-',$t);
							
							if (count($arr) != 2 || !is_numeric($min) || !is_numeric($max) || $min > $max)
							{
								if ($debug) echo "<p>Syntax error in $u='$t', allowed is 'min-max', min <= max, min='$min', max='$max'</p>\n";

								return False;
							}
							for ($i = (int)$min; $i <= $max; ++$i)
							{
								$times[$u][$i] = True;
							}
						}
						else
						{
							if ($t == '*') $t = '*/1';

							list($one,$inc) = $arr = explode('/',$t);
							
							if (!(is_numeric($one) && count($arr) == 1 || 
							      count($arr) == 2 && is_numeric($inc)))
							{
								if ($debug) echo "<p>Syntax error in $u='$t', allowed is a number or '{*|range}/inc', inc='$inc'</p>\n";

								return False;
							}
							if (count($arr) == 1)
							{
								$times[$u][(int)$one] = True;
							}
							else
							{
								list($min,$max) = $arr = explode('-',$one);
								if (empty($one) || $one == '*')
								{
									$min = $min_unit[$u];
									$max = $max_unit[$u];
								}
								elseif (count($arr) != 2 || $min > $max)
								{
									if ($debug) echo "<p>Syntax error in $u='$t', allowed is '{*|min-max}/inc', min='$min',max='$max', inc='$inc'</p>\n";
									return False;
								}
								for ($i = $min; $i <= $max; $i += $inc)
								{
									$times[$u][$i] = True;
								}
							}
						}
					}
				}
				elseif ($n < $last_set || $u == 'dow')	// before last value set (or dow) => empty gets enumerated
				{
					for ($i = $min_unit[$u]; $i <= $max_unit[$u]; ++$i)
					{
						$times[$u][$i] = True;
					}
				}
				else	// => after last value set => empty is min-value
				{
					$times[$u][$min_unit[$u]] = True;
				}
			}
			if ($this->debug) { echo "enumerated times=<pre>"; print_r($times); echo "</pre>\n"; }
			
			// now we have the times enumerated, lets find the first not expired one
			//
			$found = array();
			while (!isset($found['min']))
			{
				$future = False;

				foreach($units as $u => $date_pattern)
				{
					$unit_now = $u != 'dow' ? (int)date($date_pattern) :
						(int)date($date_pattern,mktime(12,0,0,$found['month'],$found['day'],$found['year']));

					if (isset($found[$u]))
					{
						$future = $future || $found[$u] > $unit_now;
						if ($this->debug) echo "--> already have a $u = ".$found[$u].", future='$future'<br>\n";
						continue;	// already set
					}
					foreach($times[$u] as $unit_value => $nul)
					{
						switch($u)
						{
							case 'dow':
								$valid = $unit_value == $unit_now;
								break;
							case 'min':
								$valid = $future || $unit_value > $unit_now;
								break;
							default:
								$valid = $future || $unit_value >= $unit_now;
								break;
							
						}
						if ($valid && ($u != $next || $unit_value > $over))	 // valid and not over
						{
							$found[$u] = $unit_value;
							$future = $future || $unit_value > $unit_now;
							break;
						}
					}
					if (!isset($found[$u]))		// we have to try the next one, if it exists
					{
						$next = array_keys($units);
						if (!isset($next[count($found)-1]))
						{
							if ($this->debug) echo "<p>Nothing found, exiting !!!</p>\n";
							return False;							
						}
						$next = $next[count($found)-1];
						$over = $found[$next];
						unset($found[$next]);
						if ($this->debug) echo "<p>Have to try the next $next, $u's are over for $next=$over !!!</p>\n";
						break;
					}
				}
			}
			if ($this->debug) { echo "<p>next="; print_r($found); echo "</p>\n"; }

			return mktime($found['hour'],$found['min'],0,$found['month'],$found['day'],$found['year']);
		}

		/*!
		@function cancel_timer
		@abstract cancels a timer
		@syntax cancel_timer($id)
		@param $id has to be the one used to set it.
		@result True if the timer exists and is not expired.
		*/
		function cancel_timer($id)
		{
			return $this->delete($id);
		}

		/*!
		@function last_check_run
		@abstract checks when the last check_run was run or set the run-semaphore if $semaphore == True 
		@param $semaphore if False only check, if true try to set/release the semaphore
		@param $release if $semaphore == True, tells if we should set or release the semaphore
		@result if !$set array('start' => $start,'end' => $end) with timestamps of last check_run start and end,  \
			!$end means check_run is just running. If $set returns True if it was able to get the semaphore, else False
		*/
		function last_check_run($semaphore=False,$release=False,$run_by='')
		{
			//echo "<p>last_check_run(semaphore=".($semaphore?'True':'False').",release=".($release?'True':'False').")</p>\n";
			if ($semaphore)
			{
				$this->db->lock($this->db_table,'write');	// this will block til we get exclusive access to the table

				@set_time_limit(0);		// dont stop for an execution-time-limit
				ignore_user_abort(True);
			}
			if ($exists = $this->read('##last-check-run##'))
			{
				list(,$last_run) = each($exists);
			}
			//echo "last_run (from db)=<pre>"; print_r($last_run); echo "</pre>\n";

			if (!$semaphore)
			{
				return $last_run['data'];
			}
			elseif (!$release && !$last_run['data']['end'] && $last_run['data']['start'] > time()-600)
			{
				// already one instance running (started not more then 10min ago, else we ignore it)

				$this->db->unlock();	// unlock the table again

				//echo "<p>An other instance is running !!!</p>\n";
				return False;
			}
			// no other instance runs ==> we should run
			//
			if ($release)
			{
				$last_run['data']['end'] = time();
			}
			else
			{
				$last_run = array(
					'id'     => '##last-check-run##',
					'next'   => 0,
					'times'  => array(),
					'method' => 'none',
					'data'   => array(
						'run_by'=> $run_by,
						'start' => time(),
						'end'   => 0
					)
				);
			}
			//echo "last_run=<pre>"; print_r($last_run); echo "</pre>\n";
			$this->write($last_run,!!$exits);
			
			$this->db->unlock();

			return True;
		}

		/*!
		@function check_run
		@abstract checks if there are any jobs ready to run (timer expired) and executes them
		*/
		function check_run($run_by='')
		{
			flush();
			
			if (!$this->last_check_run(True,False,$run_by))
			{
				return False;	// cant obtain semaphore
			}
			if ($jobs = $this->read())
			{
				foreach($jobs as $id => $job)
				{
					// checking / setting up phpgw_info/user
					//
					if ($GLOBALS['phpgw_info']['user']['account_id'] != $job['account_id'])
					{
						$domain = $GLOBALS['phpgw_info']['user']['domain'];
						$lang   = $GLOBALS['phpgw_info']['user']['preferences']['common']['lang'];
						unset($GLOBALS['phpgw_info']['user']);

						if ($GLOBALS['phpgw']->session->account_id = $job['account_id'])
						{
							$GLOBALS['phpgw']->session->account_lid = $GLOBALS['phpgw']->accounts->id2name($job['account_id']);
							$GLOBALS['phpgw']->session->account_domain = $domain;
							$GLOBALS['phpgw']->session->read_repositories(False,False);
							$GLOBALS['phpgw_info']['user']  = $GLOBALS['phpgw']->session->user;
							
							if ($lang != $GLOBALS['phpgw_info']['user']['preferences']['common']['lang'])
							{
								unset($GLOBALS['lang']);
								$GLOBALS['phpgw']->translation->add_app('common');
							}
						}
						else
						{
							$GLOBALS['phpgw_info']['user']['domain'] = $domain;
						}
					}
					list($app) = explode('.',$job['method']);
					$GLOBALS['phpgw']->translation->add_app($app);

					ExecMethod($job['method'],$job['data']);
					
					// re-read job, in case it had been updated or even deleted in the method
					$updated = $this->read($id);
					if ($updated && isset($updated[$id]))
					{
						$job = $updated[$id];
						
						if ($job['next'] = $this->next_run($job['times']))
						{
							$this->write($job,True);
						}
						else	// no further runs
						{
							$this->delete($job['id']);
						}
					}
				}
			}
			$this->last_check_run(True,True,$run_by);	// release semaphore

			return $jobs ? count($jobs) : False;
		}

		/*!
		@function read
		@abstract reads all matching db-rows / jobs
		@syntax reay($id=0)
		@param $id =0 reads all expired rows / jobs ready to run\
			!= 0 reads all rows/jobs matching $id (sql-wildcards '%' and '_' can be used)
		@result db-rows / jobs as array or False if no matches
		*/
		function read($id=0)
		{
			if (strpos($id,'%') !== False || strpos($id,'_') !== False)
			{
				$id = $this->db->quote($id);
				$where = "async_id LIKE $id AND async_id != '##last-check-run##'";
			}
			elseif (!$id)
			{
				$where = 'async_next <= '.time()." AND async_id != '##last-check-run##'";
			}
			else
			{
				$where = array('async_id' => $id);
			}
			$this->db->select($this->db_table,'*',$where,__LINE__,__FILE__);

			$jobs = array();
			while ($this->db->next_record())
			{
				$id = $this->db->f('async_id');

				$jobs[$id] = array(
					'id'     => $id,
					'next'   => $this->db->f('async_next'),
					'times'  => unserialize($this->db->f('async_times')),
					'method' => $this->db->f('async_method'),
					'data'   => unserialize($this->db->f('async_data')),
					'account_id'   => $this->db->f('async_account_id')
				);
				//echo "job id='$id'<pre>"; print_r($jobs[$id]); echo "</pre>\n";
			}
			if (!count($jobs))
			{
				return False;
			}
			return $jobs;
		}
		
		/*!
		@function write
		@abstract write a job / db-row to the db
		@syntax write($job,$exists = False)
		@param $job db-row as array
		@param $exits if True, we do an update, else we check if update or insert necesary
		*/
		function write($job,$exists = False)
		{
			$data = array(
				'async_next'      => $job['next'],
				'async_times'     => serialize($job['times']),
				'async_method'    => $job['method'],
				'async_data'      => serialize($job['data']),
				'async_account_id'=> $job['account_id'],
			);
			if ($exists)
			{ 
				$this->db->update($this->db_table,$data,array('async_id' => $job['id']),__LINE__,__FILE__);
			}
			else
			{
				$this->db->insert($this->db_table,$data,array('async_id' => $job['id']),__LINE__,__FILE__);
			}
		}

		/*!
		@function delete
		@abstract delete db-row / job with $id
		@result False if $id not found else True
		*/
		function delete($id)
		{
			$this->db->delete($this->db_table,array('async_id' => $id),__LINE__,__FILE__);

			return $this->db->affected_rows();
		}
		
		function find_binarys()
		{
			static $run = False;
			if ($run)
			{
				return;
			}
			$run = True;

			if (substr(php_uname(), 0, 7) == "Windows") 
			{
				// ToDo: find php-cgi on windows
			}
			else
			{
				$binarys = array(
					'php'  => '/usr/bin/php',
					'php4' => '/usr/bin/php4',		// this is for debian
					'crontab' => '/usr/bin/crontab'
				);
				foreach ($binarys as $name => $path)
				{
					$this->$name = $path;	// a reasonable default for *nix

					if (!($Ok = @is_executable($this->$name)))
					{
						if (file_exists($this->$name))
						{
							echo '<p>'.lang('%1 is not executable by the webserver !!!',$this->$name)."</p>\n";
							$perms = fileperms($this->$name);
							if (!($perms & 0x0001) && ($perms & 0x0008))	// only executable by group
							{
								$group = posix_getgrgid(filegroup($this->$name));
								$webserver = posix_getpwuid(posix_getuid ());
								echo '<p>'.lang("You need to add the webserver user '%1' to the group '%2'.",$webserver['name'],$group['name'])."</p>\n";							}
						}
						if ($fd = popen('/bin/sh -c "type -p '.$name.'"','r'))
						{
							$this->$name = fgets($fd,256);
							@pclose($fd);
						}
						if ($pos = strpos($this->$name,"\n"))
						{
							$this->$name = substr($this->$name,0,$pos);
						}
					}
					if (!$Ok && !@is_executable($this->$name))
					{
						$this->$name = $name;	// hopefully its in the path
					}
					//echo "<p>$name = '".$this->$name."'</p>\n";
				}
				if ($this->php4[0] == '/')	// we found a php4 binary
				{
					$this->php = $this->php4;
				}
			}
		
		}
		
		/*!
		@function installed
		@abstract checks if phpgwapi/cron/asyncservices.php is installed as cron-job
		@syntax installed()
		@result the times asyncservices are run (normaly 'min'=>'* /5') or False if not installed or 0 if crontab not found
		@note Not implemented for Windows at the moment, always returns 0
		*/
		function installed()
		{
			if ($this->only_fallback) {
				return 0;
			}
			$this->find_binarys();
			
			if (!is_executable($this->crontab))
			{
				//echo "<p>Error: $this->crontab not found !!!</p>";
				return 0;
			}
			$times = False;
			$this->other_cronlines = array();
			if (($crontab = popen('/bin/sh -c "'.$this->crontab.' -l" 2>&1','r')) !== False)
			{
				while ($line = fgets($crontab,256))
				{
					if ($this->debug) echo 'line '.++$n.": $line<br>\n";
					$parts = split(' ',$line,6);

					if ($line[0] == '#' || count($parts) < 6 || ($parts[5][0] != '/' && substr($parts[5],0,3) != 'php')) 
					{
						// ignore comments
						if ($line[0] != '#')
						{
							$times['error'] .= $line;
						}
					} 
					elseif (strstr($line,$this->cronline) !== False)
					{
						$cron_units = array('min','hour','day','month','dow');
						foreach($cron_units as $n => $u)
						{
							$times[$u] = $parts[$n];
						}
						$times['cronline'] = $line;
					}
					else
					{
						$this->other_cronlines[] = $line;
					}
				}
				@pclose($crontab);
			}
			return $times;
		}
		
		/*!
		@function insall
		@abstract installs /phpgwapi/cron/asyncservices.php as cron-job
		@syntax install($times)
		@param $times array with keys 'min','hour','day','month','dow', not set is equal to '*'.
			False means de-install our own crontab line
		@result the times asyncservices are run, False if they are not installed,
			0 if crontab not found and ' ' if crontab is deinstalled
		@note Not implemented for Windows at the moment, always returns 0
		*/
		function install($times)
		{
			if ($this->only_fallback && $times !== False) {
				return 0;
			}
			$this->installed();	// find other installed cronlines

			if (($crontab = popen('/bin/sh -c "'.$this->crontab.' -" 2>&1','w')) !== False)
			{
				if (is_array($this->other_cronlines))
				{
					foreach ($this->other_cronlines as $cronline)
					{
						fwrite($crontab,$cronline);		// preserv the other lines on install
					}
				}
				if ($times !== False)
				{
					$cron_units = array('min','hour','day','month','dow');
					$cronline = '';
					foreach($cron_units as $cu)
					{
						$cronline .= (isset($times[$cu]) ? $times[$cu] : '*') . ' ';
					}
					$cronline .= $this->php.' -q '.$this->cronline."\n";
					//echo "<p>Installing: '$cronline'</p>\n";
					fwrite($crontab,$cronline);
				}
				@pclose($crontab);
			}
			return $times !== False ? $this->installed() : ' ';
		}
	}