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[0] in function chmod in /var/www/hopeinstoughton_www/wp-content/plugins/simple-universal-google-analytics/main.php on line 8
[1] in function include_once in /var/www/hopeinstoughton_www/wp-settings.php on line 560
[2] in function require_once in /var/www/hopeinstoughton_www/wp-config.php on line 85
[3] in function require_once in /var/www/hopeinstoughton_www/wp-load.php on line 50
[4] in function require_once in /var/www/hopeinstoughton_www/wp-blog-header.php on line 13
[5] in function require in /var/www/hopeinstoughton_www/index.php on line 17

<?php

class Cron_Model extends Database_Model {
    
	const CRONTAB = '/usr/bin/crontab';
	private $running = FALSE;

	private function _Createkey($entrypoint, $includeSite = FALSE) {
		$hash = $includeSite ? md5(__DIR__) . '/' : '';		// this essentially the site identifier
		if (is_string($entrypoint)) {
			return $hash . str_replace(['>', '<', ';', '|', '/'], '', strtolower($entrypoint));
		}
        if ($entrypoint[0] === NULL) {
            $classname = 'null';
        } else {
            $class = get_class($entrypoint[0]);
            if (is_a($entrypoint[0], 'moduleMain')) {
                $elements = explode('\\', $class);
                array_pop($elements);
                $class = array_pop($elements);
            }
            $classname = strtolower($class);
        }
		$ep = str_replace(['_', '>', '<', ';', '|', '/'], ['-', '', '', '', '', ''], strtolower($entrypoint[1]));
		return $hash . $classname . '/' . $ep;
	}
	
	// what version of php is being used, and where is the cli version?
	// assumes linux
	public function getExecutable() {
		$major = PHP_MAJOR_VERSION;
		$minor = PHP_MINOR_VERSION;
		$dir = PHP_BINDIR;
		$executable = "$dir/php{$major}.{$minor}";
		if (file_exists($executable)) return $executable;

		$executable = "$dir/php{$major}";
		if (file_exists($executable)) return $executable;
		
		$executable = '/etc/alternatives/php';		// default php
		if (is_link($executable)) {
			return readlink($executable);
		}
		return PHP_BINARY;
	}
	
    public function CreateCommandLine($entrypoint) {
		$key = $this->_Createkey($entrypoint, FALSE);
		$exe = $this->getExecutable();
		if (is_string($entrypoint) && file_exists($entrypoint)) {
			$command = $exe . ' -q ' . $entrypoint;
		} elseif (is_a($entrypoint[0], 'controller')) {
			$command = $exe . ' -q ' . HOME . '/public/index.php "uri=' . $key . '"';
		} elseif (is_a($entrypoint[0], 'moduleMain')) {
			$command = $exe . ' -q ' . HOME . '/public/index.php "uri=/~/' . $key . '"';
        } elseif (is_string($entrypoint)) {
			$command = $exe . ' -q ' . HOME . '/public/index.php "uri=' . $entrypoint . '"';
		} else {
			return '';
		}
		return $command;
	}
	
	private function _loadCron() {
		$command = self::CRONTAB . ' -l';
		$output = `export CRONTAB_NOHEADER=NO; $command`;
//		$output = `$command`;
		$lines = explode("\n", trim($output));
		// remove crontab lines if present
		$c = count($lines);
		if ($c >= 3) {
			if (strpos($lines[2], 'Cron version') !== FALSE) {
				unset($lines[2]);
				if (strpos($lines[1], 'installed on') !== FALSE) {
					unset($lines[1]);
				}
				if (strpos($lines[0], 'DO NOT EDIT THIS FILE') !== FALSE) {
					unset($lines[0]);
				}
			}
		}
		return $lines;
	}
	
	private function _saveCron($cron) {
		$tmp = tempnam(sys_get_temp_dir(), 'cron');
		$items = join("\n", $cron) . "\n";
		file_put_contents($tmp, $items);
		$command = self::CRONTAB . ' < ' . $tmp;
		$x = `$command 2>&1`;
		unlink($tmp);
		return $x;
	}

	public function AddCron($time, $entrypoint, $debug = FALSE) {
		$key = $this->_CreateKey($entrypoint, TRUE);
		$command = $this->CreateCommandLine($entrypoint);
		if ($debug) {
            $tmp = sys_get_temp_dir();
			$command .= ' >> ' . $tmp . '/' . str_replace('/', '-', $key) . '.log 2>&1';
		} else {
			$command .= ' > /dev/null 2>&1';
		}
		$key = '##' . $key;
		$cron = $this->_loadCron();
		$text = $time . ' ' . $command;
		
		$found = 0;
		foreach($cron as $index => $cron_item) {
			if ($cron_item == $key) {
				if ($cron[$index+1] == $text) return TRUE;		// unchanged - no need to update
				$found = 1;
				$cron[$index+1] = $text;
			}
		}
	
		if (!$found) {
			// if we have the command elsewhere in the cron, remove it
			$text = $time . ' ' . $command;
			if (($p = strpos($command, '>')) !== FALSE) {
				$basecommand = substr($command, 0, $p);
			} else {
				$basecommand = $command;
			}
			foreach($cron as $index => $cron_item) {
				if (strpos($cron_item, $basecommand) !== FALSE) {
					unset($cron[$index]);
				}
			}
			$cron[] = $key;
			$cron[] = $text;
		}
		return $this->_SaveCron($cron);
	}

	public function RemoveCron($entrypoint) {
		$key = '##' . $this->_CreateKey($entrypoint, TRUE);
		$cron = $this->_loadCron();
		foreach($cron as $index => $cron_item) {
			if ($cron_item == $key) {
				unset($cron[$index+1]);
				unset($cron[$index]);
				$this->_SaveCron($cron);
				return TRUE;
			}
		}
		return FALSE;
	}
    
	// keep track of running events - and when each one is scheduled to run next
	// is event set to run this time?  Lock it so that at next tick, it will not run. unlock when execution is eventually complete
    
    public function Tick($now = 0) {
		if (!$now) $now = time();
//		error_log(gmdate('Y-m-d H:i ', $now) . "Tick");
// 		echo gmdate('Y-m-d H:i ', $now) . "Tick\n";
		// get a list of scheduled events
		$events = hook_list('cron');

		//when should each one execute next?
        $next_event_time = [];
		if ($events !== NULL) {
			foreach($events as $priority => $hook_entries) {
				foreach($hook_entries as $event) {
                    $id = $event->ID();
                    $next_event_time[$id] = [
						'start_time' => 0, 
						'running' => false, 
						'event' => $event
					];
				}
			}
		}
		
        // get next run time for all events
        $records = array_keys($next_event_time);
        $this->query('select * from `events`')
				->whereOr($this->wherein('event_id', $records), $this->where('event_id like "%:%"') );
        $data = $this->get();
		$this->DbErr();
		
        foreach($data as $dataitem) {
            $id = $dataitem->event_id;
            $next_event_time[$id]['start_time'] = $dataitem->start_time;
            $next_event_time[$id]['running'] = !empty($dataitem->running);
			$next_event_time[$id]['data']	= $dataitem->AsArray();
        }
        
        $this->tablename('events');
        foreach($next_event_time as $id => &$param) {
            $update = FALSE;
			if (strpos($id, ':') !== FALSE) {												// this is a delayed custom event
				[ $event_type, $event_id ]  = explode(':', $id, 2);
				$param = hook_execute('custom.event.' . $event_type, $param);				// create an event object
				$update = $param['update'] ?? FALSE;
				$param['running'] = FALSE;
				
			} elseif ($param['start_time'] < $now - 30 && !$param['running'] && $param['start_time'] > 0) {           	// if not running, or last event expired
                $param['start_time'] = $param['event']->NextEvent($now);
                $update = TRUE;
            } elseif ($param['running'] && $param['start_time'] < $now - 3600)  {       	// if execution too long:
        // 2019/04 THIS IS THE CURRENT PROBLEM - Process is currently "running"
        //      timeout/error check: if running, and event start time was more than an hour, reset status, determine next event time
                $param['start_time'] = $param['event']->NextEvent($now);
				$param['running'] = FALSE;
                $update = TRUE;
            } elseif (!$param['start_time'] && !$param['running']) {						// never run before - create the first entry
                $param['start_time'] = $param['event']->NextEvent($now);
                $update = TRUE;
			}
            if ($update) {
				// get name of entrypoint
				$callback = $param['event']->Execute();
				if (is_array($callback)) {
					$callback = get_class($callback[0]) . '::' . $callback[1];
//					error_log(gmdate('Y-m-d H:i ', $now) . "- $callback");
				} else {
					$callback = NULL;
				}
				if (empty($param['start_time'])) $param['start_time'] = 0;					// this event does not have a specific cron-based start time
                $this->InsertOrUpdate([
                        'event_id' 		=> $param['event']->ID(),
                     ],[
                        'start_time' 	=> $param['start_time'],
						'running' 		=> $param['running'] ? 1 : 0,
						'cmt_date'		=> gmdate('Y-m-d H:i', $param['start_time']),
						'cmt_module'	=> $callback,
                     ]);
//                $this->DbErr();
            }
        }
        unset($param);
        
        foreach($next_event_time as $id => $param) {
/*            $x = $now + 30;
            $running = $param['running'] ? 'running' : 'not running';
            $fs = gmdate('Y-m-d H:i:s', $param['start_time']);
            $fx = gmdate('Y-m-d H:i:s', $x);
            echo "$id: {$param['start_time']} < {$x} - $running\n";
            echo "requested start time: {$fs} < current time: {$fx}\n"; */
            if ($param['start_time'] > 0 && $param['start_time'] < $now + 30 && !$param['running'] && is_object($param['event'])) {
				$fx = gmdate('Y-m-d H:i');
                echo "$fx - Launching process $id...\n";
				error_log("$fx - Launching process $id...");
				$this->Execute($param['event'], $now);	// spawn new process in background
            }
        }
   }
   
	public function IsRunning() {
		return $this->running;
	}
	
	public function Execute($event, $now = 0, $updateDatabase = TRUE ) {
		if (function_exists('pcntl_fork')) {		// from command command line (via crontab)
			$pid = pcntl_fork();
			if ($pid == -1) {
				 die('could not fork');
				 // execute synch?
			} else if ($pid) {		// are we the parent - do nothing
				 
			} else {				// we are the child
				$this->_executeEvent($event, $now, $updateDatabase);      // spawn new process
				exit;
			}
		} else {
			error_log(gmdate('Y-m-d H:i ', $now) . " - no pcntl_fork");
			// run from apache/web request
			$this->_executeEvent($event, $now, $updateDatabase);
		}
	}

	private function _executeEvent($event, $now = 0, $updateDatabase = TRUE) {
		try {
			$this->Database_Reopen(); 		// To fix "Database error: Error: MySQL server has gone away [2006]";
			if ($updateDatabase) {
				if (!$now) $now = time();
				$new_time = $event->NextEvent($now + 30);
				if ($new_time === FALSE) $new_time = 0;
				$this->TableName('events')
					->InsertOrUpdate([
						'event_id' => $event->ID(),
					],[
						'start_time' 		=> $new_time,
						'cmt_date'		=> gmdate('Y-m-d H:i', $new_time),
						'running' 		=> 1,
				]);
			}
			//       execute callback function
			$this->running = TRUE;
			$callback = $event->Execute();
			if (is_callable($callback)) {
				call_user_func($callback, $event);
			}
			$this->running = FALSE;

		} catch (\Exception $e) {
			echo "Exception: " . $e->getMessage() . "\n";
		// log exception?
		}
		if ($updateDatabase) {
			$this->TableName('events')
				->InsertOrUpdate([
					'event_id' => $event->ID(),
				],[
					'running' => 0,
			]);
			$this->DbErr();
		}
   }
   
}