<?php

/**
 * Interface to the external task manager.
 */
class Taskmanager
{
	
	private static $sock = false;
	
	private static function init()
	{
		if (self::$sock !== false) return;
		self::$sock = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
		socket_set_option(self::$sock, SOL_SOCKET, SO_RCVTIMEO, array('sec' => 0, 'usec' => 100000));
		socket_set_option(self::$sock, SOL_SOCKET, SO_SNDTIMEO, array('sec' => 0, 'usec' => 100000));
		socket_connect(self::$sock, '127.0.0.1', 9215);
	}

	public static function submit($task, $data, $async)
	{
		self::init();
		$seq = (string)mt_rand();
		$data = json_encode($data);
		$message = "$seq, $task, $data";
		$sent = socket_send(self::$sock, $message, strlen($message), 0);
		if ($async) return true;
		$reply = self::readReply($seq);
		if (!is_array($reply)) return false;
		return $reply;
	}

	public static function status($taskId)
	{
		self::init();
		$seq = (string)mt_rand();
		$message = "$seq, status, $taskId";
		$sent = socket_send(self::$sock, $message, strlen($message), 0);
		$reply = self::readReply($seq);
		if (!is_array($reply)) return false;
		return $reply;
	}
	
	public static function waitComplete($taskId)
	{
		for ($i = 0; $i < 10; ++$i) {
			$status = self::status($taskId);
			if (!isset($status['statusCode'])) break;
			if ($status['statusCode'] != TASK_PROCESSING && $status['statusCode'] != TASK_WAITING) break;
			usleep(150000);
		}
		return $status;
	}

	public static function release($taskId)
	{
		self::init();
		$seq = (string)mt_rand();
		$message = "$seq, release, $taskId";
		socket_send(self::$sock, $message, strlen($message), 0);
	}
	
	/**
	 * 
	 * @param type $seq
	 * @return mixed the decoded json data for that message as an array, or null on error
	 */
	private static function readReply($seq)
	{
		$tries = 0;
		while (($bytes = socket_recvfrom(self::$sock, $buf, 90000, 0, $bla1, $bla2)) !== false) {
			$parts = explode(',', $buf, 2);
			if (count($parts) == 2 && $parts[0] == $seq) {
				return json_decode($parts[1], true);
			}
			if (++$tries > 10) return false;
		}
		//error_log(socket_strerror(socket_last_error(self::$sock)));
		return false;
	}

}

foreach (array('TASK_FINISHED', 'TASK_ERROR', 'TASK_WAITING', 'NO_SUCH_TASK', 'TASK_PROCESSING') as $i) {
	define($i, $i);
}