<?php

namespace NoccyLabs\Ipc\Interop\Channel;

/**
 * Channel based on streams
 * 
 */
class StreamChannel implements ChannelInterface
{
    protected $stream;

    /**
     * Constructor
     *
     * @param resource|string $stream
     */
    public function __construct($stream)
    {
        if (!is_resource($stream)) {
            if (!is_string($stream)) {
                throw new \LogicException("Invalid stream");
            }
            $stream = stream_socket_client($stream, $errno, $errstr);
            if (!$stream) {
                throw new \RuntimeException(sprintf("%d %s", $errno, $errstr));
            }
        }
        
        $this->stream = $stream;

        stream_set_blocking($stream, false);
    }
    
    /**
     * {@inheritDoc}
     *
     * @param mixed $data
     * @return void
     */
    public function send($data)
    {
        fwrite($this->stream, json_encode($data)."\0");
    }

    /**
     * {@inheritDoc}
     *
     * @return mixed
     */
    public function receive()
    {
        $buf = fread($this->stream, 8192);
        if (!$buf) {
            return false;
        }

        return json_decode(rtrim($buf, "\0"), true);
    }

    /**
     * {@inheritDoc}
     *
     * @return boolean
     */
    public function isOpen(): bool
    {
        return is_resource($this->stream);
    }

    /**
     * Create a pair of connected StreamChannel instances
     *
     * @return StreamChannel[]
     */
    public static function createPair()
    {
        $fd = stream_socket_pair(STREAM_PF_UNIX, STREAM_SOCK_STREAM, STREAM_IPPROTO_IP);

        return [
            new StreamChannel($fd[0]),
            new StreamChannel($fd[1])
        ];
    }

}