<?php
/**
 * Compact RCON client for Minecraft with improved read loop & timeouts.
 */
class Rcon {
    private $host;
    private $port;
    private $password;
    private $socket;
    private $req_id;
    private $timeout;

    const SERVERDATA_AUTH = 3;
    const SERVERDATA_EXECCOMMAND = 2;

    public function __construct($host, $port, $password, $timeout = 3) {
        $this->host = $host;
        $this->port = intval($port);
        $this->password = $password;
        $this->timeout = $timeout;
        $this->socket = null;
        $this->req_id = random_int(1, 0x7fffffff);
    }

    public function connect() {
        $this->socket = @fsockopen($this->host, $this->port, $errno, $errstr, $this->timeout);
        if (!$this->socket) return false;
        stream_set_timeout($this->socket, $this->timeout);
        stream_set_blocking($this->socket, true);

        $pkt = $this->buildPacket($this->req_id, self::SERVERDATA_AUTH, $this->password);
        fwrite($this->socket, $pkt);

        $resp = $this->readPacket();
        if ($resp === false) { $this->disconnect(); return false; }
        if (isset($resp['id']) && intval($resp['id']) == -1) { $this->disconnect(); return false; }
        return true;
    }

    public function disconnect() {
        if ($this->socket) { fclose($this->socket); $this->socket = null; }
    }

    public function sendCommand($command) {
        if (!$this->socket) return false;
        $this->req_id = ($this->req_id + 1) & 0x7fffffff;
        $pkt = $this->buildPacket($this->req_id, self::SERVERDATA_EXECCOMMAND, $command);
        fwrite($this->socket, $pkt);

        $out = '';
        $start = time();
        while (true) {
            $resp = $this->readPacket();
            if ($resp === false) break;
            if (isset($resp['body'])) $out .= $resp['body'];
            $meta = stream_get_meta_data($this->socket);
            if ($meta['timed_out']) break;
            if (time() - $start > $this->timeout) break;
            if (strlen($resp['body']) < 4096) break;
        }
        return $out;
    }

    private function buildPacket($id, $type, $body) {
        $payload = pack('V', $id) . pack('V', $type) . $body . "\x00\x00";
        $size = strlen($payload);
        return pack('V', $size) . $payload;
    }

    private function readPacket() {
        $sizeData = $this->fread_all(4);
        if ($sizeData === false) return false;
        $sizeArr = unpack('Vsize', $sizeData);
        $size = $sizeArr['size'];
        if ($size <= 0) return false;
        $payload = $this->fread_all($size);
        if ($payload === false) return false;
        $id = unpack('Vid', substr($payload, 0, 4))['id'] ?? 0;
        $type = unpack('Vtype', substr($payload, 4, 4))['type'] ?? 0;
        $body = substr($payload, 8, $size - 10);
        return ['id' => $id, 'type' => $type, 'body' => $body];
    }

    private function fread_all($len) {
        $data = '';
        $read = 0;
        $start = time();
        while ($read < $len) {
            $chunk = @fread($this->socket, $len - $read);
            if ($chunk === false) return false;
            if ($chunk === '') {
                $meta = stream_get_meta_data($this->socket);
                if ($meta['timed_out'] || (time() - $start) > $this->timeout) return false;
                usleep(10000);
                continue;
            }
            $data .= $chunk;
            $read += strlen($chunk);
        }
        return $data;
    }
}