<?php

declare(strict_types=1);

/**
 * @author Pavel Djundik
 *
 * @link https://xpaw.me
 * @link https://github.com/xPaw/PHP-Source-Query
 *
 * @license GNU Lesser General Public License, version 2.1
 *
 * @internal
 */

namespace xPaw\SourceQuery;

use xPaw\SourceQuery\Exception\AuthenticationException;
use xPaw\SourceQuery\Exception\InvalidPacketException;
use xPaw\SourceQuery\Exception\SocketException;

/**
 * Class SourceRcon
 *
 * @package xPaw\SourceQuery
 *
 * @uses AuthenticationException
 * @uses InvalidPacketException
 * @uses SocketException
 */
final class SourceRcon
{
    /**
     * Points to socket class
     */
    private BaseSocket $Socket;

    /** @var ?resource */
    private $RconSocket;
    private int $RconRequestId = 0;

    public function __construct(BaseSocket $Socket)
    {
        $this->Socket = $Socket;
    }

    public function Close(): void
    {
        if ($this->RconSocket) {
            fclose($this->RconSocket);

            $this->RconSocket = null;
        }

        $this->RconRequestId = 0;
    }

    public function Open(): void
    {
        if (!$this->RconSocket) {
            $RconSocket = @fsockopen($this->Socket->Address, $this->Socket->Port, $ErrNo, $ErrStr, $this->Socket->Timeout);

            if ($ErrNo || !$RconSocket) {
                throw new SocketException('Can\'t connect to RCON server: ' . $ErrStr, SocketException::CONNECTION_FAILED);
            }

            $this->RconSocket = $RconSocket;
            stream_set_timeout($this->RconSocket, $this->Socket->Timeout);
            stream_set_blocking($this->RconSocket, true);
        }
    }

    public function Write(int $Header, string $String = ''): bool
    {
        // Pack the packet together
        $Command = pack('VV', ++$this->RconRequestId, $Header) . $String . "\x00\x00";

        // Prepend packet length
        $Command = pack('V', strlen($Command)) . $Command;
        $Length  = strlen($Command);

        return $Length === fwrite($this->RconSocket, $Command, $Length);
    }

    public function Read(): Buffer
    {
        $Buffer = new Buffer();
        $Buffer->Set(fread($this->RconSocket, 4));

        if ($Buffer->Remaining() < 4) {
            throw new InvalidPacketException('Rcon read: Failed to read any data from socket', InvalidPacketException::BUFFER_EMPTY);
        }

        $PacketSize = $Buffer->GetLong();

        $Buffer->Set(fread($this->RconSocket, $PacketSize));

        $Data = $Buffer->Get();

        $Remaining = $PacketSize - strlen($Data);

        while ($Remaining > 0) {
            $Data2 = fread($this->RconSocket, $Remaining);

            $PacketSize = strlen($Data2);

            if ($PacketSize === 0) {
                throw new InvalidPacketException('Read ' . strlen($Data) . ' bytes from socket, ' . $Remaining . ' remaining', InvalidPacketException::BUFFER_EMPTY);
            }

            $Data .= $Data2;
            $Remaining -= $PacketSize;
        }

        $Buffer->Set($Data);

        return $Buffer;
    }

    public function Command(string $Command): string
    {
        $this->Write(SourceQuery::SERVERDATA_EXECCOMMAND, $Command);
        $Buffer = $this->Read();

        $Buffer->GetLong(); // RequestID

        $Type = $Buffer->GetLong();

        if ($Type === SourceQuery::SERVERDATA_AUTH_RESPONSE) {
            throw new AuthenticationException('Bad rcon_password.', AuthenticationException::BAD_PASSWORD);
        } elseif ($Type !== SourceQuery::SERVERDATA_RESPONSE_VALUE) {
            throw new InvalidPacketException('Invalid rcon response.', InvalidPacketException::PACKET_HEADER_MISMATCH);
        }

        $Data = $Buffer->Get();

        // We do this stupid hack to handle split packets
        // See https://developer.valvesoftware.com/wiki/Source_RCON_Protocol#Multiple-packet_Responses
        if (strlen($Data) >= 4000) {
            $this->Write(SourceQuery::SERVERDATA_REQUESTVALUE);

            do {
                $Buffer = $this->Read();

                $Buffer->GetLong(); // RequestID

                if ($Buffer->GetLong() !== SourceQuery::SERVERDATA_RESPONSE_VALUE) {
                    break;
                }

                $Data2 = $Buffer->Get();

                if ($Data2 === "\x00\x01\x00\x00\x00\x00") {
                    break;
                }

                $Data .= $Data2;
            } while (true);
        }

        return rtrim($Data, "\0");
    }

    public function Authorize(string $Password): void
    {
        $this->Write(SourceQuery::SERVERDATA_AUTH, $Password);
        $Buffer = $this->Read();

        $RequestID = $Buffer->GetLong();
        $Type      = $Buffer->GetLong();

        // If we receive SERVERDATA_RESPONSE_VALUE, then we need to read again
        // More info: https://developer.valvesoftware.com/wiki/Source_RCON_Protocol#Additional_Comments

        if ($Type === SourceQuery::SERVERDATA_RESPONSE_VALUE) {
            $Buffer = $this->Read();

            $RequestID = $Buffer->GetLong();
            $Type      = $Buffer->GetLong();
        }

        if ($RequestID === -1 || $Type !== SourceQuery::SERVERDATA_AUTH_RESPONSE) {
            throw new AuthenticationException('RCON authorization failed.', AuthenticationException::BAD_PASSWORD);
        }
    }
}