<?php
namespace PhpAmqpLib\Wire\IO;

use PhpAmqpLib\Exception\AMQPIOException;
use PhpAmqpLib\Exception\AMQPRuntimeException;
use PhpAmqpLib\Exception\AMQPTimeoutException;
use PhpAmqpLib\Helper\MiscHelper;
use PhpAmqpLib\Wire\AMQPWriter;

class StreamIO extends AbstractIO
{
    /** @var  string */
    protected $host;

    /** @var int */
    protected $port;

    /** @var int */
    protected $connection_timeout;

    /** @var int */
    protected $read_write_timeout;

    /** @var resource */
    protected $context;

    /** @var bool */
    protected $keepalive;

    /** @var int */
    protected $heartbeat;

    /** @var float */
    protected $last_read;

    /** @var float */
    protected $last_write;

    /** @var resource */
    private $sock;

    /** @var bool */
    private $canDispatchPcntlSignal;

    /**
     * @param string $host
     * @param int $port
     * @param int $connection_timeout
     * @param int $read_write_timeout
     * @param null $context
     * @param bool $keepalive
     * @param int $heartbeat
     */
    public function __construct(
        $host,
        $port,
        $connection_timeout,
        $read_write_timeout,
        $context = null,
        $keepalive = false,
        $heartbeat = 0
    ) {
        $this->host = $host;
        $this->port = $port;
        $this->connection_timeout = $connection_timeout;
        $this->read_write_timeout = $read_write_timeout;
        $this->context = $context;
        $this->keepalive = $keepalive;
        $this->heartbeat = $heartbeat;
        $this->canDispatchPcntlSignal = extension_loaded('pcntl') && function_exists('pcntl_signal_dispatch')
            && (defined('AMQP_WITHOUT_SIGNALS') ? !AMQP_WITHOUT_SIGNALS : true);
    }

    /**
     * Sets up the stream connection
     *
     * @throws \PhpAmqpLib\Exception\AMQPRuntimeException
     * @throws \Exception
     */
    public function connect()
    {
        $errstr = $errno = null;

        if ($this->context) {
            $remote = sprintf('ssl://%s:%s', $this->host, $this->port);
            $this->sock = @stream_socket_client(
                $remote,
                $errno,
                $errstr,
                $this->connection_timeout,
                STREAM_CLIENT_CONNECT,
                $this->context
            );
        } else {
            $remote = sprintf('tcp://%s:%s', $this->host, $this->port);
            $this->sock = @stream_socket_client(
                $remote,
                $errno,
                $errstr,
                $this->connection_timeout,
                STREAM_CLIENT_CONNECT
            );
        }

        if (!$this->sock) {
            throw new AMQPRuntimeException(sprintf(
                'Error Connecting to server (%s): %s',
                $errno,
                $errstr
            ), $errno);
        }

        list($sec, $uSec) = MiscHelper::splitSecondsMicroseconds($this->read_write_timeout);
        if (!stream_set_timeout($this->sock, $sec, $uSec)) {
            throw new AMQPIOException('Timeout could not be set');
        }

        stream_set_blocking($this->sock, 1);

        if ($this->keepalive) {
            $this->enable_keepalive();
        }
    }

    /**
     * Reconnects the socket
     */
    public function reconnect()
    {
        $this->close();
        $this->connect();
    }

    /**
     * @param $n
     * @throws \PhpAmqpLib\Exception\AMQPIOException
     * @return mixed|string
     */
    public function read($n)
    {
        $res = '';
        $read = 0;

        while ($read < $n && !feof($this->sock) && (false !== ($buf = fread($this->sock, $n - $read)))) {
            $this->check_heartbeat();

            if ($buf === '') {
                if ($this->canDispatchPcntlSignal) {
                    pcntl_signal_dispatch();
                }
                continue;
            }

            $read += mb_strlen($buf, 'ASCII');
            $res .= $buf;

            $this->last_read = microtime(true);
        }

        if (mb_strlen($res, 'ASCII') != $n) {
            throw new AMQPIOException(sprintf(
                'Error reading data. Received %s instead of expected %s bytes',
                mb_strlen($res, 'ASCII'),
                $n
            ));
        }

        return $res;
    }

    /**
     * @param $data
     * @return mixed|void
     * @throws \PhpAmqpLib\Exception\AMQPRuntimeException
     * @throws \PhpAmqpLib\Exception\AMQPTimeoutException
     */
    public function write($data)
    {
        $len = mb_strlen($data, 'ASCII');
        while (true) {
            if (is_null($this->sock)) {
                throw new AMQPRuntimeException('Broken pipe or closed connection');
            }

            if (false === ($written = @fwrite($this->sock, $data))) {
                throw new AMQPRuntimeException('Error sending data');
            }

            if ($written === 0) {
                throw new AMQPRuntimeException('Broken pipe or closed connection');
            }

            if ($this->timed_out()) {
                throw new AMQPTimeoutException('Error sending data. Socket connection timed out');
            }

            $len = $len - $written;
            if ($len > 0) {
                $data = mb_substr($data, 0 - $len, 0 - $len, 'ASCII');
            } else {
                $this->last_write = microtime(true);
                break;
            }
        }
    }

    /**
     * Heartbeat logic: check connection health here
     */
    protected function check_heartbeat()
    {
        // ignore unless heartbeat interval is set
        if ($this->heartbeat !== 0 && $this->last_read && $this->last_write) {
            $t = microtime(true);
            $t_read = round($t - $this->last_read);
            $t_write = round($t - $this->last_write);

            // server has gone away
            if (($this->heartbeat * 2) < $t_read) {
                $this->reconnect();
            }

            // time for client to send a heartbeat
            if (($this->heartbeat / 2) < $t_write) {
                $this->write_heartbeat();
            }
        }
    }

    /**
     * Sends a heartbeat message
     */
    protected function write_heartbeat()
    {
        $pkt = new AMQPWriter();
        $pkt->write_octet(8);
        $pkt->write_short(0);
        $pkt->write_long(0);
        $pkt->write_octet(0xCE);
        $val = $pkt->getvalue();
        $this->write($pkt->getvalue());
    }

    public function close()
    {
        if (is_resource($this->sock)) {
            fclose($this->sock);
        }
        $this->sock = null;
    }

    /**
     * @return resource
     */
    public function get_socket()
    {
        return $this->sock;
    }

    /**
     * @return resource
     */
    public function getSocket()
    {
        return $this->get_socket();
    }

    /**
     * @param $sec
     * @param $usec
     * @return int|mixed
     */
    public function select($sec, $usec)
    {
        $read = array($this->sock);
        $write = null;
        $except = null;

        return stream_select($read, $write, $except, $sec, $usec);
    }

    /**
     * @return mixed
     */
    protected function timed_out()
    {
        // get status of socket to determine whether or not it has timed out
        $info = stream_get_meta_data($this->sock);

        return $info['timed_out'];
    }

    /**
     * @throws \PhpAmqpLib\Exception\AMQPIOException
     */
    protected function enable_keepalive()
    {
        if (!function_exists('socket_import_stream')) {
            throw new AMQPIOException('Can not enable keepalive: function socket_import_stream does not exist');
        }

        if (!defined('SOL_SOCKET') || !defined('SO_KEEPALIVE')) {
            throw new AMQPIOException('Can not enable keepalive: SOL_SOCKET or SO_KEEPALIVE is not defined');
        }

        $socket = socket_import_stream($this->sock);
        socket_set_option($socket, SOL_SOCKET, SO_KEEPALIVE, 1);
    }
}