<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\VarDumper\Server;

use Psr\Log\LoggerInterface;
use Symfony\Component\VarDumper\Cloner\Data;
use Symfony\Component\VarDumper\Cloner\Stub;

/**
 * A server collecting Data clones sent by a ServerDumper.
 *
 * @author Maxime Steinhausser <maxime.steinhausser@gmail.com>
 *
 * @final
 */
class DumpServer
{
    private $host;
    private $socket;
    private $logger;

    public function __construct(string $host, LoggerInterface $logger = null)
    {
        if (false === strpos($host, '://')) {
            $host = 'tcp://'.$host;
        }

        $this->host = $host;
        $this->logger = $logger;
    }

    public function start(): void
    {
        if (!$this->socket = stream_socket_server($this->host, $errno, $errstr)) {
            throw new \RuntimeException(sprintf('Server start failed on "%s": '.$errstr.' '.$errno, $this->host));
        }
    }

    public function listen(callable $callback): void
    {
        if (null === $this->socket) {
            $this->start();
        }

        foreach ($this->getMessages() as $clientId => $message) {
            $payload = @unserialize(base64_decode($message), ['allowed_classes' => [Data::class, Stub::class]]);

            // Impossible to decode the message, give up.
            if (false === $payload) {
                if ($this->logger) {
                    $this->logger->warning('Unable to decode a message from {clientId} client.', ['clientId' => $clientId]);
                }

                continue;
            }

            if (!\is_array($payload) || \count($payload) < 2 || !$payload[0] instanceof Data || !\is_array($payload[1])) {
                if ($this->logger) {
                    $this->logger->warning('Invalid payload from {clientId} client. Expected an array of two elements (Data $data, array $context)', ['clientId' => $clientId]);
                }

                continue;
            }

            list($data, $context) = $payload;

            $callback($data, $context, $clientId);
        }
    }

    public function getHost(): string
    {
        return $this->host;
    }

    private function getMessages(): iterable
    {
        $sockets = [(int) $this->socket => $this->socket];
        $write = [];

        while (true) {
            $read = $sockets;
            stream_select($read, $write, $write, null);

            foreach ($read as $stream) {
                if ($this->socket === $stream) {
                    $stream = stream_socket_accept($this->socket);
                    $sockets[(int) $stream] = $stream;
                } elseif (feof($stream)) {
                    unset($sockets[(int) $stream]);
                    fclose($stream);
                } else {
                    yield (int) $stream => fgets($stream);
                }
            }
        }
    }
}
