<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4 foldmethod=marker: */
// +---------------------------------------------------------------------------
// | SWAN [ $_SWANBR_SLOGAN_$ ]
// +---------------------------------------------------------------------------
// | Copyright $_SWANBR_COPYRIGHT_$
// +---------------------------------------------------------------------------
// | Version  $_SWANBR_VERSION_$
// +---------------------------------------------------------------------------
// | Licensed ( $_SWANBR_LICENSED_URL_$ )
// +---------------------------------------------------------------------------
// | $_SWANBR_WEB_DOMAIN_$
// +---------------------------------------------------------------------------

namespace Kafka;

/**
 * +------------------------------------------------------------------------------
 * Kafka broker socket
 * +------------------------------------------------------------------------------
 *
 * @package
 * @version $_SWANBR_VERSION_$
 * @copyright Copyleft
 * @author $_SWANBR_AUTHOR_$
 * +------------------------------------------------------------------------------
 */
class Socket
{

	const READ_MAX_LEN = 5242880; // read socket max length 5MB
//	const READ_MAX_LEN = 2097152; // read socket max length 5MB

	/**
	 * max write socket buffer
	 * fixed:send of 8192 bytes failed with errno=11 Resource temporarily
	 * fixed:'fwrite(): send of ???? bytes failed with errno=35 Resource temporarily unavailable'
	 * unavailable error info
	 */
	const MAX_WRITE_BUFFER = 2048;

	/**
	 * Send timeout in seconds.
	 *
	 * @var float
	 * @access private
	 */
	private $sendTimeoutSec = 0;

	/**
	 * Send timeout in microseconds.
	 *
	 * @var float
	 * @access private
	 */
	private $sendTimeoutUsec = 100000;

	/**
	 * Recv timeout in seconds
	 *
	 * @var float
	 * @access private
	 */
	private $recvTimeoutSec = 0;

	/**
	 * Recv timeout in microseconds
	 *
	 * @var float
	 * @access private
	 */
	private $recvTimeoutUsec = 750000;

	/**
	 * Stream resource
	 *
	 * @var mixed
	 * @access private
	 */
	private $stream = null;

	/**
	 * Socket host
	 *
	 * @var mixed
	 * @access private
	 */
	private $host = null;

	/**
	 * Socket port
	 *
	 * @var mixed
	 * @access private
	 */
	private $port = -1;

	/**
	 * Max Write Attempts
	 * @var int
	 * @access private
	 */
	private $maxWriteAttempts = 3;

	/**
	 * Reader watcher
	 * @var int
	 * @access private
	 */
	private $readWatcher = 0;

	/**
	 * Write watcher
	 * @var int
	 * @access private
	 */
	private $writeWatcher = 0;

	/**
	 * Write watcher
	 * @var int
	 * @access private
	 */
	private $writeBuffer = '';

	/**
	 * Reader buffer
	 * @var int
	 * @access private
	 */
	private $readBuffer = '';

	/**
	 * Reader need buffer length
	 * @var int
	 * @access private
	 */
	private $readNeedLength = 0;

	/**
	 * __construct
	 *
	 * @access public
	 * @param $host
	 * @param $port
	 * @param int $recvTimeoutSec
	 * @param int $recvTimeoutUsec
	 * @param int $sendTimeoutSec
	 * @param int $sendTimeoutUsec
	 */
	public function __construct($host, $port, $recvTimeoutSec = 0, $recvTimeoutUsec = 750000, $sendTimeoutSec = 0, $sendTimeoutUsec = 100000)
	{
		$this->host = $host;
		$this->port = $port;
		$this->setRecvTimeoutSec($recvTimeoutSec);
		$this->setRecvTimeoutUsec($recvTimeoutUsec);
		$this->setSendTimeoutSec($sendTimeoutSec);
		$this->setSendTimeoutUsec($sendTimeoutUsec);
	}

	/**
	 * @param float $sendTimeoutSec
	 */
	public function setSendTimeoutSec(float $sendTimeoutSec)
	{
		$this->sendTimeoutSec = $sendTimeoutSec;
	}

	/**
	 * @param float $sendTimeoutUsec
	 */
	public function setSendTimeoutUsec(float $sendTimeoutUsec)
	{
		$this->sendTimeoutUsec = $sendTimeoutUsec;
	}

	/**
	 * @param float $recvTimeoutSec
	 */
	public function setRecvTimeoutSec(float $recvTimeoutSec)
	{
		$this->recvTimeoutSec = $recvTimeoutSec;
	}

	/**
	 * @param float $recvTimeoutUsec
	 */
	public function setRecvTimeoutUsec(float $recvTimeoutUsec)
	{
		$this->recvTimeoutUsec = $recvTimeoutUsec;
	}

	/**
	 * @param int $number
	 */
	public function setMaxWriteAttempts(int $number)
	{
		$this->maxWriteAttempts = $number;
	}


	/**
	 * Connects the socket
	 *
	 * @access public
	 * @return void
	 */
	public function connect()
	{
		if (!$this->isSocketDead()) {
			return;
		}

		if (empty($this->host)) {
			throw new \Kafka\Exception('Cannot open null host.');
		}
		if ($this->port <= 0) {
			throw new \Kafka\Exception('Cannot open without port.');
		}

		$this->stream = @fsockopen(
			$this->host,
			$this->port,
			$errno,
			$errstr,
			$this->sendTimeoutSec + ($this->sendTimeoutUsec / 1000000)
		);

		if ($this->stream == false) {
			$error = 'Could not connect to '
				. $this->host . ':' . $this->port
				. ' (' . $errstr . ' [' . $errno . '])';
			throw new \Kafka\Exception($error);
		}

		stream_set_blocking($this->stream, 0);
		stream_set_read_buffer($this->stream, 0);

		$this->readWatcher = \Amp\onReadable($this->stream, function () {
			do {
				if (!$this->isSocketDead()) {
					$newData = @fread($this->stream, self::READ_MAX_LEN);
				} else {
					$this->reconnect();
					return;
				}
				if ($newData) {
					$this->read($newData);
					$newData = true;
				}
			} while ($newData);
		});

		$this->writeWatcher = \Amp\onWritable($this->stream, function () {
			$this->write();
		}, array('enable' => false));
	}


	/**
	 * reconnect the socket
	 *
	 * @access public
	 * @return void
	 */
	public function reconnect()
	{
		$this->close();
		$this->connect();
	}


	/**
	 * get the socket
	 *
	 * @access public
	 * @return void
	 */
	public function getSocket()
	{
		return $this->stream;
	}


	public $onReadable;

	/**
	 * set on readable callback function
	 *
	 * @access public
	 * @param \Closure $read
	 * @return void
	 */
	public function SetOnReadable(\Closure $read)
	{
		$this->onReadable = $read;
	}


	/**
	 * close the socket
	 *
	 * @access public
	 * @return void
	 */
	public function close()
	{
		\Amp\cancel($this->readWatcher);
		\Amp\cancel($this->writeWatcher);
		if (is_resource($this->stream)) {
			fclose($this->stream);
		}
		$this->readBuffer = '';
		$this->writeBuffer = '';
		$this->readNeedLength = 0;
	}

	/**
	 * checks if the socket is a valid resource
	 *
	 * @access public
	 * @return boolean
	 */
	public function isResource()
	{
		return is_resource($this->stream);
	}


	/**
	 * Read from the socket at most $len bytes.
	 *
	 * This method will not wait for all the requested data, it will return as
	 * soon as any data is received.
	 *
	 * @param $data
	 */
	public function read($data)
	{
		$this->readBuffer .= $data;
		do {
			if ($this->readNeedLength == 0) {
				if (strlen($this->readBuffer) < 4) {
					return;
				}
				$dataLen = \Kafka\Protocol\Protocol::unpack(\Kafka\Protocol\Protocol::BIT_B32, substr($this->readBuffer, 0, 4));
				$this->readNeedLength = $dataLen;
				$this->readBuffer = substr($this->readBuffer, 4);
			}

			if (strlen($this->readBuffer) < $this->readNeedLength) {
				return;
			}
			$data = substr($this->readBuffer, 0, $this->readNeedLength);

			$this->readBuffer = substr($this->readBuffer, $this->readNeedLength);
			$this->readNeedLength = 0;
			call_user_func($this->onReadable, $data, (int)$this->stream);
		} while (strlen($this->readBuffer));
	}


	/**
	 * Write to the socket.
	 *
	 * @param null $data
	 */
	public function write($data = null)
	{
		if ($data != null) {
			$this->writeBuffer .= $data;
		}
		$bytesToWrite = strlen($this->writeBuffer);
		$bytesWritten = @fwrite($this->stream, $this->writeBuffer);

		if ($bytesToWrite === $bytesWritten) {
			\Amp\disable($this->writeWatcher);
		} elseif ($bytesWritten >= 0) {
			\Amp\enable($this->writeWatcher);
		} elseif ($this->isSocketDead()) {
			$this->reconnect();
		}
		$this->writeBuffer = substr($this->writeBuffer, $bytesWritten);
	}


	/**
	 * check the stream is close
	 *
	 * @return bool
	 */
	protected function isSocketDead()
	{
		return !is_resource($this->stream) || @feof($this->stream);
	}
}